US20070112344A1 - Endoluminal implant with therapeutic and diagnostic capability - Google Patents
Endoluminal implant with therapeutic and diagnostic capability Download PDFInfo
- Publication number
- US20070112344A1 US20070112344A1 US11/551,673 US55167306A US2007112344A1 US 20070112344 A1 US20070112344 A1 US 20070112344A1 US 55167306 A US55167306 A US 55167306A US 2007112344 A1 US2007112344 A1 US 2007112344A1
- Authority
- US
- United States
- Prior art keywords
- transducer
- coupled
- stent
- therapeutic
- endoluminal implant
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Images
Classifications
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B8/00—Diagnosis using ultrasonic, sonic or infrasonic waves
- A61B8/06—Measuring blood flow
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/0002—Remote monitoring of patients using telemetry, e.g. transmission of vital signals via a communication network
- A61B5/0031—Implanted circuitry
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/68—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient
- A61B5/6846—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient specially adapted to be brought in contact with an internal body part, i.e. invasive
- A61B5/6847—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient specially adapted to be brought in contact with an internal body part, i.e. invasive mounted on an invasive device
- A61B5/6862—Stents
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/68—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient
- A61B5/6846—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient specially adapted to be brought in contact with an internal body part, i.e. invasive
- A61B5/6867—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient specially adapted to be brought in contact with an internal body part, i.e. invasive specially adapted to be attached or implanted in a specific body part
- A61B5/6876—Blood vessel
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B8/00—Diagnosis using ultrasonic, sonic or infrasonic waves
- A61B8/56—Details of data transmission or power supply
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
- A61M1/00—Suction or pumping devices for medical purposes; Devices for carrying-off, for treatment of, or for carrying-over, body-liquids; Drainage systems
- A61M1/36—Other treatment of blood in a by-pass of the natural circulatory system, e.g. temperature adaptation, irradiation ; Extra-corporeal blood circuits
- A61M1/3621—Extra-corporeal blood circuits
- A61M1/3653—Interfaces between patient blood circulation and extra-corporal blood circuit
- A61M1/3656—Monitoring patency or flow at connection sites; Detecting disconnections
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
- A61M37/00—Other apparatus for introducing media into the body; Percutany, i.e. introducing medicines into the body by diffusion through the skin
- A61M37/0092—Other apparatus for introducing media into the body; Percutany, i.e. introducing medicines into the body by diffusion through the skin using ultrasonic, sonic or infrasonic vibrations, e.g. phonophoresis
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B2560/00—Constructional details of operational features of apparatus; Accessories for medical measuring apparatus
- A61B2560/02—Operational features
- A61B2560/0204—Operational features of power management
- A61B2560/0214—Operational features of power management of power generation or supply
- A61B2560/0219—Operational features of power management of power generation or supply of externally powered implanted units
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/145—Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue
- A61B5/14532—Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue for measuring glucose, e.g. by tissue impedance measurement
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B8/00—Diagnosis using ultrasonic, sonic or infrasonic waves
- A61B8/04—Measuring blood pressure
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B8/00—Diagnosis using ultrasonic, sonic or infrasonic waves
- A61B8/12—Diagnosis using ultrasonic, sonic or infrasonic waves in body cavities or body tracts, e.g. by using catheters
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B8/00—Diagnosis using ultrasonic, sonic or infrasonic waves
- A61B8/44—Constructional features of the ultrasonic, sonic or infrasonic diagnostic device
- A61B8/4483—Constructional features of the ultrasonic, sonic or infrasonic diagnostic device characterised by features of the ultrasound transducer
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
- A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
- A61F2/02—Prostheses implantable into the body
- A61F2/04—Hollow or tubular parts of organs, e.g. bladders, tracheae, bronchi or bile ducts
- A61F2/06—Blood vessels
- A61F2/07—Stent-grafts
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
- A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
- A61F2/82—Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
- A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
- A61F2/02—Prostheses implantable into the body
- A61F2/04—Hollow or tubular parts of organs, e.g. bladders, tracheae, bronchi or bile ducts
- A61F2/06—Blood vessels
- A61F2/07—Stent-grafts
- A61F2002/072—Encapsulated stents, e.g. wire or whole stent embedded in lining
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
- A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
- A61F2/02—Prostheses implantable into the body
- A61F2/04—Hollow or tubular parts of organs, e.g. bladders, tracheae, bronchi or bile ducts
- A61F2/06—Blood vessels
- A61F2/07—Stent-grafts
- A61F2002/075—Stent-grafts the stent being loosely attached to the graft material, e.g. by stitching
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
- A61F2250/00—Special features of prostheses classified in groups A61F2/00 - A61F2/26 or A61F2/82 or A61F9/00 or A61F11/00 or subgroups thereof
- A61F2250/0001—Means for transferring electromagnetic energy to implants
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
- A61F2250/00—Special features of prostheses classified in groups A61F2/00 - A61F2/26 or A61F2/82 or A61F9/00 or A61F11/00 or subgroups thereof
- A61F2250/0001—Means for transferring electromagnetic energy to implants
- A61F2250/0002—Means for transferring electromagnetic energy to implants for data transfer
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
- A61N1/00—Electrotherapy; Circuits therefor
- A61N1/18—Applying electric currents by contact electrodes
- A61N1/20—Applying electric currents by contact electrodes continuous direct currents
- A61N1/30—Apparatus for iontophoresis, i.e. transfer of media in ionic state by an electromotoric force into the body, or cataphoresis
- A61N1/303—Constructional details
- A61N1/306—Arrangements where at least part of the apparatus is introduced into the body
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
- A61N1/00—Electrotherapy; Circuits therefor
- A61N1/18—Applying electric currents by contact electrodes
- A61N1/32—Applying electric currents by contact electrodes alternating or intermittent currents
- A61N1/325—Applying electric currents by contact electrodes alternating or intermittent currents for iontophoresis, i.e. transfer of media in ionic state by an electromotoric force into the body
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
- A61N5/00—Radiation therapy
- A61N5/06—Radiation therapy using light
- A61N5/0601—Apparatus for use inside the body
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
- A61N5/00—Radiation therapy
- A61N5/06—Radiation therapy using light
- A61N5/0613—Apparatus adapted for a specific treatment
- A61N5/062—Photodynamic therapy, i.e. excitation of an agent
Definitions
- the MUX 38 is used to select the specific transducer 44 - 46 for receiving the RF excitation signal produced by the XMTR 62 so that the transducer 44 - 46 produces an ultrasonic wave and then receives the echo from fluid flowing through the stent to produce a received data signal that is output through the RX MOD/XMTR 64 .
- the TX/RX switch 72 prevents the signal applied by the TX AMP 58 from overdriving the input to the RX AMP 60 , effectively isolating the RX AMP 60 during the time that the RF signal is applied to the transducer 44 - 46 to excite it so that it produces the ultrasonic wave.
- a housing 96 on the external coil 90 provides RF shielding against electromagnetic interference (EMI).
- the housing 96 for the external coil 90 is conductive, grounded and surrounds the external coil 90 except where the surfaces of the generally “C-shaped” core 94 are opposite the RF coupling coil 30 A.
- the RF shield comprising the housing 96 is attached to an internal braided shield 99 of the cable 98 . Inside the power supply and patient monitoring console (not shown in FIG. 7 ) to which the cable 98 is coupled, the shield 99 is connected to ground.
- the RF shield on the external coil 90 along with shields provided around transducers 44 - 46 on the stent 106 , minimizes external EMI radiation due to the use of the present invention within a patient's body.
- FIG. 9 An embodiment of a RF coupling coil 30 C comprising a stent 106 B is shown in FIG. 9 to illustrate the configuration discussed above.
- the RF coupling coil 30 C comprises a woven mesh 132 fabricated from insulated wire so that overlapping segments of the woven mesh 132 do not electrically connect in the center of the stent 106 B.
- the wires comprising the woven mesh 132 are electrically coupled together at nodes 134 , producing the RF coupling coil 30 C.
- the nodes 134 are insulated from contact with body fluids or other conductors.
- the rear electrode 196 and the front electrode 200 comprise multi-layer structures (although separate layers are not shown).
- the electrodes 196 and 200 will include a metallic layer that bonds well to the piezoelectric plastic layer 198 , for example, titanium, followed by a highly conductive layer, for example, copper, followed by an oxidation resistant layer, for example, gold, and includes other metallic barrier layers, where appropriate, to prevent reaction between these layers.
- Such multi-layer systems are conventional and are suited for use as the electrodes 196 and 200 in the conformal transducer arrays 174 A and 174 B.
Landscapes
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Heart & Thoracic Surgery (AREA)
- Veterinary Medicine (AREA)
- General Health & Medical Sciences (AREA)
- Biomedical Technology (AREA)
- Public Health (AREA)
- Animal Behavior & Ethology (AREA)
- Medical Informatics (AREA)
- Biophysics (AREA)
- Molecular Biology (AREA)
- Surgery (AREA)
- Pathology (AREA)
- Physics & Mathematics (AREA)
- Vascular Medicine (AREA)
- Hematology (AREA)
- Anesthesiology (AREA)
- Computer Networks & Wireless Communication (AREA)
- Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
- Radiology & Medical Imaging (AREA)
- Dermatology (AREA)
- Cardiology (AREA)
- Media Introduction/Drainage Providing Device (AREA)
- Prostheses (AREA)
Abstract
An apparatus includes an endoluminal implant, a RF coupling coil coupled to the endoluminal implant and a therapeutic transducer electrically coupled to the RF coupling coil and physically coupled to the endoluminal implant. The RF coupling coil supplies electrical power to the therapeutic transducer. The therapeutic transducer has a capability for delivering therapeutic energy to a lumen disposed within the endoluminal implant in response to signals coupled via the RF coupling coil.
Description
- This invention relates generally to implantable devices, and, more particularly, to implantable medical devices having therapeutic or diagnostic functions within a lumen of an endoluminal implant such as a stent or other type of endovascular conduit, and methods related to such implantable medical devices.
- In the 1970s, the technique of percutaneous transluminal coronary angioplasty (PTCA) was developed for the treatment of atherosclerosis. Atherosclerosis is the build-up of fatty deposits or plaque on the inner walls of a patient's arteries; these lesions decrease the effective size of the artery lumen and limit blood flow through the artery, prospectively causing a myocardial infarction or heart attack if the lesions occur in coronary arteries that supply oxygenated blood to the heart muscles. In the angioplasty procedure, a guide wire is inserted into the femoral artery and is passed through the aorta into the diseased coronary artery. A catheter having a balloon attached to its distal end is advanced along the guide wire to a point where the sclerotic lesions limit blood flow through the coronary artery. The balloon is then inflated, compressing the lesions radially outward against the wall of the artery and substantially increasing the size of its internal lumen, to improve blood circulation through the artery.
- Increasingly, stents are being used in place of or in addition to PTCA for treatment of atherosclerosis, with the intent of minimizing the need to repeatedly open an atherosclerotic artery. Although a number of different designs for stents exist in the prior art, all are generally configured as elongate cylindrical structures that are provided in a first state and can assume a second, different state, with the second state having a substantially greater diameter than the first state. A stent is implanted in a patient using an appropriate delivery system for the type of stent being implaced within the patient's arterial system. There are two basic types of stents—those that are expanded radially outward due to the force from an inflated angioplasty type balloon, such as the Palmaz-Schatz stent, the Gianturco-Roubin stent and the Strecker stent, and those that are self expanding, such as the Maass double helix spiral stent, the Nitinol stent (made of nickel titanium memory alloy), the Gianturco stent and the Wallstent. Problems with the Maass double helix spiral stent and the Nitinol stent have limited their use.
- Stents are sometimes used following a PTCA procedure if the artery is totally occluded or if the lesions have occluded a previously placed surgical graft. Typically, a stent constrained within an introducer sheath is advanced to a site within the patient's artery through a guide catheter. For the balloon expanded type, after the introducer sheath is retracted, a balloon disposed inside the stent is inflated to a pressure ranging from about six to ten atmospheres. The force produced by the inflated balloon expands the stent radially outward beyond its elastic limit, stretching the vessel and compressing the lesion to the inner wall of the vessel. A self expanding stent expands due to spring force following its implacement in the artery, after a restraining sheath is retracted from the compressed stent, or in the case of the Nitinol version, the stent assumes its expanded memory state after being warmed above the transition temperature of the Nitinol alloy (e.g., above 30° C.). Following the expansion process, when the balloon catheter is used, the balloon is removed from inside the stent and the catheter and other delivery apparatus is withdrawn. The lumen through the vessel is then substantially increased, improving blood flow.
- After a stent or other endoluminal device is implanted, a clinical examination and either an angiography or an ultrasonic morphological procedure is performed to evaluate the success of the stent emplacement procedure in opening the diseased artery or vessel. These tests are typically repeated periodically, e.g., at six-month intervals, since restenosis of the artery may occur. Due to the nature of the tests, the results of the procedure can only be determined qualitatively, but not quantitatively, with any degree of accuracy or precision. It would clearly be preferable to monitor the flow of blood through the stent after its implacement in a vessel, both immediately following the treatment for the stenosis and thereafter, either periodically or on a continuous basis. Measurements of volumetric rate and/or flow velocity of the blood through the stent would enable a medical practitioner to much more accurately assess the condition of the stent and of the artery in which the stent is implanted. Currently, no prior art mechanism is available that is implantable inside a blood vessel for monitoring blood flow conditions through a stent.
- Following stent implantation, it is difficult to monitor the condition of the affected area. Stents often fail after a period of time and for a variety of reasons. Several of the causal mechanisms are amenable to drug treatment. It is highly desirable in at least some of these cases to localize the drug treatment to the site of the graft or surgery. For example, when thrombus forms in a given area, thrombolytic drugs are capable of providing significant assistance in resolving the thrombosis, but may present problems such as hemorrhaging, if they also act in other portions of the patient's body.
- The present invention provides a capability for including a therapeutic transducer together with an endoluminal implant such as a stent or stent graft. Therapeutic transducers may include ultrasonic, magnetic, iontophoretic, heating or optical devices, which may permit localized drug delivery or localized drug activation. Provision is made for delivering energy to the implanted transducers and for coupling signals to or from the implanted transducers. The present invention also permits inclusion of diagnostic transducers together with the endoluminal implant and allows signals to be transmitted from the diagnostic transducers to an area outside of the patient's body.
- The present invention can allow steps that may be taken to restore full fluid flow through, e.g., a stent that is becoming restricted. In these cases, it is desirable to initiate treatment before the problem proceeds too far to be corrected without stent replacement or further PTCA treatment. Clearly, it would be preferable to be able to monitor the condition of a stent without resorting to invasive surgical procedures and without prescribing medication that may not be necessary, so that the useful life of the stent may be extended, problems associated stent failure avoided and so that medications are only prescribed when required by the known condition of the stent and associated vasculature.
- Other advantages that may be realized via embodiments of the present invention including monitoring of other parameters measurable within a stent or other type of endoluminal implant using one or more appropriate sensors or transducers according to embodiments of the present invention. For example, monitoring pressure at the distal and proximal ends of the lumen in the implant and determining the differential pressure can provide an indication of fluid velocity through the lumen. Temperature can also be used to monitor fluid flow by applying heat to the fluid within the lumen and monitoring the rate at which the temperature of the fluid decreases as the fluid flows through the lumen of the implant. Integrated circuit (IC) transducers are currently known and available for sensing the levels of many different types of biochemical substances, such as glucose, potassium, sodium, chloride ions and insulin. Any of these IC sensors could be provided in an endoluminal implant to monitor these parameters.
- Since it is impractical to pass a conductor through the wall of an artery or vessel for long periods of time, use of a conventional sensor that produces signals indicative of flow through a stent, which must be conveyed through a conductor that extends through the wall of the vessel and outside the patient's body, is not a practical solution to this problem. Also, any active flow indicative sensor must be energized with electrical power. Again, it is not practical to supply power to such a sensor through any conductor that perforates the vessel wall or that passes outside the patient's body.
- In addition to stents, the generic term endoluminal implant encompasses stent grafts, which are also sometimes referred to as “spring grafts.” A stent graft is a combination of a stent and a synthetic graft is endoluminally implanted at a desired point in a vessel. Helically coiled wires comprising the stent are attached to the ends of the synthetic graft and are used to hold the graft in position. Sometimes, hooks are provided on the stent to ensure that the graft remains in the desired position within the vessel. Clearly, it is advantageous to monitor the status of flow and other parameters through a stent graft, just as noted above in regard to a stent.
- Endoluminal implants are used in other body passages in addition to blood vessels. For example, they are sometimes used to maintain an open lumen through the urethra, or through the cervix. A stent placed adjacent to an enlarged prostate gland can prevent the prostate from blocking the flow of urine through the urethra. Tracheal and esophageal implants are further examples of endoluminal implants. In these and other uses of endoluminal implants, provision for monitoring parameters related to the status of flow and other conditions in the patient's body is desirable. Information provided by monitoring such parameters, and localized drug delivery or drug activation, can enable more effective medical treatment of a patient through use of embodiments of the present invention.
- Another advantage that may be realized through practice of embodiments of the present invention is to be able to activate a therapeutic device on the stent or stent graft that would allow the physician to activate drugs known to be effective in preventing further tissue growth within the stent or stent graft in situations where it is determined that tissue ingrowth is threatening the viability of a stent or stent graft. Again, the therapeutic device should be able to be supplied with electrical power from time to time from a location outside the patient's body.
- Yet another advantage that may be realized through practice of the present invention is the treatment of tumors or organs that are downstream of the blood vessel that includes a stent that is coupled to a transducer. The transducer may be remotely activated to facilitate localized drug delivery or to provide other therapeutic benefits.
- The foregoing aspects and many of the attendant advantages of this invention will become more readily appreciated as the same becomes better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein:
-
FIG. 1 is a block diagram according to the invention showing a first embodiment of an implantable electronic circuit for coupling electrical signals to or from a selected transducer of a plurality of transducers. -
FIG. 2 is a block diagram of a second embodiment of an implantable electronic circuit for coupling electrical signals to or from a transducer using separate multiplexers for transmit and receive functions. -
FIG. 3 is a block diagram of a third embodiment of an implantable electronic circuit for coupling electrical signals to or from a transducer using separate multiplexers and amplifiers for transmit and receive functions. -
FIG. 4 is a block diagram of a fourth embodiment of an implantable electronic circuit for coupling electrical signals to or from a transducer that employs a local transmitter to excite a selected transducer, and a modulator/transmitter for transmitting signals from the transducers. -
FIG. 5 is a block diagram of a fifth embodiment of an implantable electronic circuit for coupling electrical signals to or from a transducer, where one transducer is selected for transmitting and receiving, and a modulator/transmitter is used for transmitting the signal produced by the receiving transducer. -
FIG. 6 is a block diagram of a sixth embodiment of an implantable electronic circuit for monitoring the status of a stent or stent graft, wherein one of a plurality of transducers is selectively coupled to a modulator/transmitter or a receiver. -
FIG. 7 is a cross-sectional view of a radio frequency (RF) coupling coil in a stent that is implanted in a blood vessel, and an external coil that is electromagnetically coupled to the RF coupling coil. -
FIG. 8 is a cross-sectional view of a RF coupling coil in a stent implanted in a blood vessel, and includes a block that represents an implanted coil, which is electromagnetically coupled to the RF coupling coil. -
FIG. 9 is a side elevational view of a woven mesh RF coupling coil that comprises a wall of a stent. -
FIG. 10 is a cut-away side elevational view of a further embodiment of an external coil and a side elevational view of a blood vessel in which a stent is implanted that includes a saddle-shaped RF coupling coil integrated within the wall of the stent. -
FIG. 11A is a side elevational view (showing only the foreground) of a portion of a metal tube-type stent with nonconductive weld joints, illustrating a RF coupling coil wrapped around the stent in a pre-expansion configuration. -
FIG. 11B is a side elevational view (showing only the foreground) of a portion of a zigzag wire stent with non-conductive joints, illustrating a RF coupling coil wrapped around the stent in a pre-expansion configuration. -
FIG. 12 is a cut-away view of a portion of a limb showing a stent implanted at a substantial depth within a blood vessel, and an external coupling coil that encompasses the stent. -
FIG. 13 is a side elevational schematic view of a dual beam conformal array transducer on an expandable carrier band for use in a stent. -
FIG. 14 is an end elevational view of the conformal array transducer ofFIG. 13 , within a stent. -
FIG. 15 is a plan view of the conformal array transducer shown inFIGS. 13 and 14 , cut along a cut line to display the dual conformal arrays in a flat disposition. -
FIG. 16A is a cross-sectional side view of a portion of a stent in which are disposed transversely oriented transducers for monitoring flow using correlation measurements. -
FIG. 16B is a transverse cross-sectional view of the stent and transversely oriented transducers shown inFIG. 16A . -
FIG. 17 is an enlarged partial transverse cross-sectional view of the layers comprising the conformal array transducer disposed on a stent within a blood vessel. -
FIG. 18 is an enlarged partial cross-sectional side view of a tilted-element transducer array disposed within a stent. -
FIG. 19A is an isometric view of an integrated circuit (IC) transducer mounted on a tubular stent. -
FIG. 19B is an enlarged partial cross-sectional side view of the implantable IC transducer mounted on the tubular stent. -
FIG. 19C is an isometric view of the implantable IC transducer mounted on a woven mesh stent. -
FIG. 19D is an enlarged partial cross-sectional side view of the implantable IC transducer mounted on the woven mesh stent. -
FIG. 20 is a side elevational schematic view showing an IC strain sensor and sensing filaments disposed on a stent. -
FIG. 21A is side elevational schematic view of a stent outline showing a deposit and ingrowth IC sensor and sensing filament. -
FIG. 21B is a cross-sectional view of a lumen of the stent inFIG. 21A , illustrating fatty tissue ingrowth. -
FIG. 22 is side elevational view of a portion of a branching artery in which a stent graft that is used for providing therapeutic functions is implanted. -
FIG. 23 illustrates an ultrasonic transducer configuration integrated with a stent or stent graft. -
FIG. 24 illustrates an embodiment of a dual frequency ultrasonic transducer. -
FIG. 25 illustrates one embodiment of a coil integrated into a stent. -
FIG. 26 illustrates another embodiment of a coil integrated into a stent. -
FIG. 27 illustrates an embodiment of an iontophoretic system for local drug delivery. -
FIG. 28 illustrates an embodiment wherein light emitting transducers are coupled to a stent. - The present invention is employed for providing therapeutic functions proximate to an endoluminal implant. As used herein and in the claims that follow, the term endoluminal implant broadly encompasses stents, stent grafts (sometimes referred to as “spring grafts”) and other types of devices that are inserted into a lumen or body passage and moved to a desired site to provide a structural benefit to the lumen. To simplify the disclosure of the present invention, most of the following discussion is directed to embodiments comprising a stent.
- In one embodiment, parameters are monitored via implanted diagnostic transducers, where the monitored parameters are directed to determining the status of the fluid flow through the endoluminal implant, and therapeutic transducers may be activated in response to the data collected from the implanted diagnostic transducers. For example, the rate or velocity of fluid flow through a body passage in which the stent has been positioned can be monitored to determine the extent of tissue growth or fatty deposits in a blood vessel in which the stent has been implanted to treat atherosclerosis. By monitoring these parameters, which are indicative of blood flow through the lumen of the stent and the blood vessel in which it is implanted, a medical practitioner can evaluate the need for further treatment or determine whether restenosis has occurred, and can locally activate drugs to control restenosis when it is determined to have occurred. This may be possible without additional surgery and without some of the complications associated with systemic administration of drugs. Moreover, other physical and biological parameters can be monitored using one or more appropriate sensors attached to a stent.
- When implanted therapeutic transducers are to be activated for an extended period of time or following an extended delay, the stent will likely need to receive electrical power from an external source to energize the implantable electronic circuitry used to activate the implanted therapeutic transducers. Similarly, when the status of fluid flow through a stent that has been implanted in a patient's vascular system (or some other parameter that is sensed proximate the stent) is to be monitored for an extended period or following an extended delay, the implanted circuitry associated with the stent will likely need to receive electrical power from an external source. This power may also be needed to convey data indicating the status of fluid flow (or other parameter) from the implanted stent to a monitoring device that is disposed outside the patient's body. In many cases, it may be desirable to monitor one or more parameters at multiple stents or at multiple locations on a single stent, or to provide therapeutic functions at more than one stent or to multiple locations within or associated with one stent. Thus, the specific transducer employed to provide a therapeutic function or transducer or sensor employed to monitor a desired parameter must be selectable so that the data signal indicating the parameter can be transmitted outside the patient's body. However, in some cases, only a single transducer (which may be operable without any implanted control electronics) may be required to provide a therapeutic function or to monitor a parameter such as fluid volumetric flow or velocity, which is indicative of the internal condition of the stent and of the blood vessel in which it is implanted.
-
FIG. 1 illustrates a first embodiment of an implantable electronic circuit for providing one or more therapeutic functions or for monitoring one or more parameters, applicable to the situation in which n transducers 44-46 are included on one or more stents implanted in the patient's body. Variations of the implantable electronic circuit shown inFIG. 1 are discussed below to accommodate specific conditions. In addition, other embodiments of implantable electronic circuits are illustrated inFIGS. 2 through 6 . These embodiments, like that ofFIG. 1 , are useful for providing power to transducers that provide therapeutic functions, e.g., that activate drugs or that assist in localized drug delivery, or that monitor fluid flow or velocity through a stent and also for transmitting data signals from the transducers to locations outside a patient's body, e.g., to an external remote monitoring console. Some of these implantable electronic circuits are better suited for certain types of therapy or measurements than others, and again, variations in the implantable electronic circuits are discussed below, where appropriate, to explain these distinctions. Examples of implantable telemetry systems are discussed in A Telemetry-Instrumentation System For Monitoring Multiple Subcutaneously Implanted Glucose Sensors by M. C. Shults et al., IEEE Trans. Biomed. Eng., Vol. 41, No. 10, October 1994, pp. 937-942 and in Integrated Circuit Implantable Telemetry Systems by J. W. Knutti et al., Eng. in Med. and Bio. Magazine, March 1983, pp. 47-50. - Each of the implantable electronic circuits shown in
FIGS. 1 through 6 are intended to be implanted within the patient's body and left in place at least during the period in which a therapeutic function may be needed or the flow conditions through one or more stents or other parameters are monitored. Although separate functional blocks are illustrated for different components of the implantable electronic circuits in these Figures, any of the implantable electronic circuits can be implemented in one or more application specific integrated circuits (ASICs) to minimize size, which is particularly important when the implantable electronic circuits are integral with a stent. The implantable electronic circuits can be either included within the wall of a stent, or may be simply implanted adjacent to blood vessel(s) in which the stent(s) is/are disposed. However, if not integral with the stent, the implantable electronic circuits must be electromagnetically coupled to the transducers, since it is impractical to extend any conductor through a wall of the blood vessel in which a stent is implanted, to couple to circuitry disposed outside the blood vessel. Therefore, in some embodiments, the implantable electronic circuits are integral with the stent so that they are implanted, together with the stent, inside the blood vessel. - Each of the implantable electronic circuits shown in
FIGS. 1 through 6 includes aRF coupling coil 30, which is coupled vialines DC power supply 32. In one embodiment, theRF coupling coil 30 is part of the expandable structure of the stent body or may instead be added to a stent, for example, by threading an insulated wire through the expandable wall of a stent. In some embodiments, theRF coupling coil 30 comprises a helical coil or saddle-shaped coil, as explained in greater detail below. The RF-to-DC power supply 32 rectifies and filters a RF excitation signal supplied from an external source to theRF coupling coil 30, providing an appropriate voltage DC power signal for the other components of the implantable electronic circuits illustrated in these Figures. In the simplest case, the RF-to-DC power supply 32 would only require rectifiers and filters as appropriate to provide any needed positive and negative supply voltages, +VS and −VS. - However, it is also contemplated that the RF-to-
DC power supply 32 may provide for a DC-to-DC conversion capability in the event that the electromagnetic signal coupled into theRF coupling coil 30 is too weak to provide the required level of DC voltage for any component. This conversion capability would increase the lower voltage produced by the direct coupling of the external RF excitation signal received by theRF coupling coil 30, to a higher DC voltage. Details of the RF-to-DC power supply 32 are not shown, since such devices are conventional. It is also contemplated that it may be necessary to limit the maximum amplitude of the RF input signal to the RF-to-DC power supply 32 to protect it or so that excessive DC supply voltages are not provided to the other components. - Alternatively, each component that must be provided with a limited DC voltage supply may include a voltage limiting component, such as a zener diode or voltage regulator (neither shown). In another embodiment, the
RF coupling coil 30 and the RF-to-DC power supply 32 ofFIGS. 1 through 6 may be replaced by a hard-wired connection to supply DC or AC power in applications where the implant is needed for a relatively short duration, where the inconvenience of the cables supplying the power is tolerable and the risk of infection is manageable. An example of a hard-wired transcutaneous connection for chronic implants is described in Silicon Ribbon Cables For Chronically Implantable Microelectrode Arrays by J. F. Hetke et al., IEEE Trans. Biomed. Eng., Vol. 41, No. 4, April 1994, pp. 314-321. - The RF-to-
DC power supply 32 may include a battery or a capacitor for storing energy so that it need not be energized when providing a therapeutic function or monitoring the flow status, or at least, should include sufficient storage capability for at least one cycle of receiving energy and transmitting data relating to the parameter being monitored. Neither a battery nor power storage capacitor are illustrated in the Figures, since they are conventional also. - Implantable electronic systems using battery power may only require the ability to receive data and control signals and may include the ability to transmit signals. As a result, they do not necessarily require access to the skin, which access facilitates efficient coupling of power signals. A battery-powered system may result in a very compact implantable system. Alternatively, a battery-powered system that also is capable of recharging the battery via power signals coupled through an implanted coil can permit continuing treatment without requiring that a physician be present throughout the treatment or requiring the patient to be in the medical facility.
- An element that is common to each of the implantable electronic circuits shown in
FIGS. 1 through 3 is aRF decode section 40, which is used for generating control signals that are responsive to information encoded in the external RF excitation signal received by theRF coupling coil 30. This information can be superimposed on the RF excitation signal, e.g., by amplitude or frequency modulating the signal. - In regard to the implantable electronic circuits shown in
FIGS. 1 through 3 , when used for monitoring fluid velocity or flow, the RF excitation frequency is the same as the frequency used to provide energy for therapeutic functions (e.g., localized drug activation) or to excite a selected ultrasonic transducer to produce an ultrasonic wave that propagates through a lumen of the stent being monitored and for conveying data from the transducer 44-46 that receives the ultrasonic waves. This approach generally simplifies the implantable electronic circuitry but may not provide optimal performance. - Therefore,
FIGS. 4 and 5 disclose implantable electronic circuitry in which the RF excitation frequency used to provide power to the RF-to-DC power supply 32 and to provide control signals to theRF decode section 40 is decoupled from the frequency that is used for exciting the transducers 44-46 and modulating any data that they provide for transmission to a point outside the patient's body. Although other types of transducers 44-46 may be employed that are energized with a RF excitation frequency, such as surface acoustic wave transducers that are used for sensing chemical substances, many transducers 44-46 only require a DC voltage to sense a desired parameter such as pressure or temperature or to provide a static magnetic field, heat or light for therapeutic purposes. - Implantable Electronic Circuits
- Referring now to
FIG. 1 , aline 36 from theRF coupling coil 30 is coupled to a multiplexer (MUX) 38 to convey signals from a selected one of a plurality of n transducers 44-46 (which are disposed at different points on a stent) that are coupled to theMUX 38. To select the transducer 44-46 that will provide a therapeutic function or a data signal related to a parameter at a specific location on a stent, theRF decode section 40 provides a control signal to theMUX 38 through MUX control lines 42. The control signal causes theMUX 38 to select a specific transducer 44-46 that is to be excited by the RF signal received by theRF coupling coil 30 and further, causes theMUX 38 to select the transducer 44-46 that will provide the data signal for transmission outside the patient's body (or at least outside the blood vessel in which the stent is disposed) via theRF coupling coil 30. - In addition to ultrasonic transducers 44-46, the implantable electronic circuit shown in
FIG. 1 can also be used in connection with pressure transducers 44-46. For ultrasonic transducers 44-46, the circuit is perhaps more applicable to the Doppler type for use in monitoring fluid velocity through a stent. If a single-vessel pulse Doppler transducer 44-46 is used, the same transducer 44-46 can be used for both transmission and reception of the ultrasonic wave, thereby eliminating the need for theMUX 38. In the event that the transducers 44-46 shown inFIG. 1 are used for transit time flow measurements, it will normally be necessary to use theMUX 38 to switch between the transducer 44-46 used for transmitting the ultrasonic wave and that used to receive the ultrasonic wave. - For a single-vessel transit time measurement, a pair of opposed transducers 44-46 that are disposed on opposite sides of the stent are typically used. In order to acquire bi-directional fluid flow data, the direction of the ultrasound wave propagation must be known, i.e., the direction in which the ultrasound wave propagates relative to the direction of fluid flow through the vessel. In this case, the
MUX 38 is required. However, for single-vessel applications in which the fluid flow is in a single known direction, the transducers 44-46 that are disposed on opposite sides of the stent can be electrically coupled in parallel or in series, eliminating any requirement for theMUX 38. The RF-to-DC power supply 32 and theRF decode section 40 could also then be eliminated, since the retarded and advanced transit time signals are superimposed on the same RF waveform transmitted by theRF coupling coil 30 to a location outside the patient's body (or outside the blood vessel in which the stent is disposed, if an internal coil is implanted adjacent the blood vessel near where the stent is implanted). Although this modification to the implantable electronic circuit shown inFIG. 1 would not permit the direction of fluid flow through a stent to be determined, the retarded and advanced transit time signals interfere over time, and their interference can be used to estimate the magnitude of fluid flow through the stent. - In some applications, a single transducer 44-46 or group of transducers 44-46 may be employed, in which case the implantable electronic circuit of
FIG. 1 may be simplified by coupling the transducer(s) 44-46 directly to theRF coupling coil 30 and eliminating theMUX 38. In this embodiment, theRF decode section 40 and the RF-to-DC power supply 32 are optional; when the transducer, for example, requires DC excitation or other excitation different than that which may be provided directly via theRF coupling coil 30, the RF-to-DC power supply 32 may be desirable. Similarly, some sensors may have more than one function and then theRF decode section 40 may also be desirable. Similarly, the implantable electronic circuits ofFIGS. 2 through 6 may be modified to provide the desired or required functionality. - In
FIG. 2 , an implantable electronic circuit is shown that uses a transmit multiplexer (TX MUX) 50 and a receive multiplexer (RX MUX) 54. In addition, a transmit (TX) switch 48 and a receive (RX) switch 52couple line 36 to theTX MUX 50 and theRX MUX 54, respectively. TheRF decode section 40 responds to instructions on the signal received from outside the patient's body by producing a corresponding MUX control signal that is conveyed to theTX MUX 50 and theRX MUX 54 overMUX control lines 56 to select the desired transducers 44-46. - When ultrasonic signals are being transmitted by one of the selected transducers 44-46, the TX switch 48 couples the RF excitation signal received by the
RF coupling coil 30 to the transducer 44-46 that is transmitting the ultrasonic signal, which is selected by theTX MUX 50. TheTX switch 48 is set up to pass excitation signals to the selected transducer 44-46 only if the signals are above a predetermined voltage level, for example, 0.7 volts. Signals below that predetermined voltage level are blocked by theTX switch 48. Similarly, the RX switch 52 couples the transducer 44-46 selected by theRX MUX 54 to theRF coupling coil 30 and passes only signals that are below the predetermined voltage level, blocking signals above that level. Accordingly, the RF signal used to excite a first transducer 44-46 selected by theTX MUX 50 passes through theTX switch 48 and the lower amplitude signal produced by a second transducer 44-46 selected by theRX MUX 54 in response to the ultrasonic signal transmitted through the stent is conveyed through theRX MUX 54 and theRX switch 52 and transmitted outside the patient's body through theRF coupling coil 30. - The implantable electronic circuit shown in
FIG. 3 is similar to that ofFIG. 2 , but it includes a transmit amplifier (TX AMP) 58 interposed between theTX switch 48 and theTX MUX 50, and a receive amplifier (RX AMP) 60 interposed between theRX MUX 54 and theRX switch 52. TheTX AMP 58 amplifies the excitation signal applied to the transducer 44-46 selected by theTX MUX 50 for producing the ultrasonic wave that is propagated through the interior lumen of a stent. Similarly, theRX AMP 60 amplifies the signal produced by the transducer 44-46 selected by theRX MUX 54 before providing the signal to theRX switch 52 for transmission outside the patient's body (or at least, outside the blood vessel in which the stent is implanted). Again, the implantable electronic circuit shown inFIG. 3 is most applicable to transit time flow measurements and employs the same frequency for both the RF excitation signal that supplies power to the RF-to-DC power supply 32 and the signal applied to a selected one of the transducers 44-46 to generate the ultrasonic wave propagating through the stent. - In contrast to the implantable electronic circuits shown in
FIGS. 1 through 3 , the implantable electronic circuit shown inFIGS. 4 through 6 enables the RF excitation frequency applied to the RF-to-DC power supply 32 to be decoupled from the frequency of the signal applied to excite any selected one of the transducers 44-46. Similarly, the signal produced by the transducer 44-46 receiving ultrasonic waves propagating through the stent is at a different frequency than the RF excitation frequency applied to the RF-to-DC power supply 32. InFIG. 4 , a transmitter (XMTR) 62 and a receive modulator/transmitter (RX MOD/XMTR) 64 are coupled to and controlled by a RF decode/control section 66. The RF decode/control section 66 determines when the excitation frequency is generated for application to a selected transmit transducer 44-46 and when the signal produced by the transducer selected to receive the ultrasonic wave is used for modulating the RF signal applied to theRF coupling coil 30. An advantage of this approach is that the RF power delivered to theRF coupling coil 30 is at an optimal frequency for penetration through the patient's body, thereby improving the efficacy with which the RF energy couples to a specific depth and location within the body. Another reason for using this approach is to enable selection of a particular frequency as necessary to comply with radio frequency allocation bands for medical equipment. Similarly, the frequency applied to any selected transducers 44-46 to stimulate their production of ultrasonic waves can be optimal for that purpose. Assuming that the two frequency bands, i.e., the RF excitation frequency band for the signal applied to the RF-to-DC power supply 32 and the frequency band of the signals applied to excite the transducers 44-46, are sufficiently separated, the RF power delivery can occur simultaneously with the excitation of a selected transducer 44-46 and the reception of the ultrasonic waves by another selected transducer 44-46. Accordingly, more RF power can be coupled into the system from the external source than in the implantable electronic circuits shown inFIGS. 1 through 3 . In some embodiments, including those where a battery is used, the RF decode/control section 66 may also include a RF oscillator for providing the RF signals to the transducers 44-46 or for coupling signals from the transducers 44-46 to external electronic apparatus. - The control signals that are supplied to the RF decode/
control section 66 via theRF coupling coil 30 can be conveyed using nearly any kind of modulation scheme, e.g., by modulating the RF excitation that powers the device, or by sending a control signal on a separate and distinct RF frequency. Also, the signals that are received from the transducer 44-46 in response to the ultrasonic wave that is propagated through the stent can be transmitted through theRF coupling coil 30 at a different frequency than the incoming excitation frequency, thereby reducing the likelihood of interference between the power supply and data signal transmission functions. - The implantable electronic circuit shown in
FIG. 4 is applicable to transit time flow measurements in which pairs of transducers 44-46 are selected for transmitting and receiving the ultrasonic wave that propagates through the one or more stents on which the transducers 44-46 are installed. The RF decode/control section 66 can be employed to control theTX MUX 50 and theRX MUX 68 to interchange the transducers 44-46 used for transmission and reception of the ultrasonic wave on successive pulses. Using this technique, the direction of the ultrasonic wave propagation through the stent is changed on alternating pulses of ultrasonic waves, enabling transit time difference information to be gathered without requiring further multiplexer programming information to be transmitted between successive ultrasonic wave pulses. This approach greatly improves the data gathering efficiency of the implantable electronic circuit shown inFIG. 4 compared to the previously described implantable electronic circuits ofFIGS. 1 through 3 . - To further improve the implantable electronic circuit shown in
FIG. 4 for use in sensing fluid velocity through a stent using a Doppler technique, the modification shown inFIG. 5 is made. InFIG. 5 , a TX/RX switch 72 is added so that the implantable electronic circuit transmits and receives through the same transducer 44-46. As a result, the separate transmit 50 and receive 54 multiplexers ofFIG. 4 are not required. Instead, theMUX 38 is used to select the specific transducer 44-46 for receiving the RF excitation signal produced by theXMTR 62 so that the transducer 44-46 produces an ultrasonic wave and then receives the echo from fluid flowing through the stent to produce a received data signal that is output through the RX MOD/XMTR 64. The TX/RX switch 72 prevents the signal applied by theTX AMP 58 from overdriving the input to theRX AMP 60, effectively isolating theRX AMP 60 during the time that the RF signal is applied to the transducer 44-46 to excite it so that it produces the ultrasonic wave. However, the echo signal received by the transducer 44-46 is allowed to reach theRX AMP 60 when the TX/RX switch 72 changes state (from transmit to receive). Generally, the implantable electronic circuit shown inFIG. 5 has the same benefits as described above in connection with the implantable electronic circuit shown inFIG. 4 . The RF decode/control section 66 responds to the information received from outside the patient's body that determines which one of the transducers 44-46 is selected at any given time by producing an appropriate MUX control signal that is supplied to theMUX 38 over the MUX control lines 56. - It is also contemplated that the RF decode/
control section 66 may cause theMUX 38 to select a different transducer 44-46 for producing/receiving the ultrasonic waves after a predefined number of transmit/receive cycles have elapsed. For example, a different transducer 44-46 may be selected after eight cycles have been implemented to transmit an ultrasonic wave into the stent and to receive back the echoes from the fluid flowing through the stent. By collecting data related to the status of flow through a stent in this manner, it becomes unnecessary to send programming information to the RF decode/control section 66 after each cycle of a transmission of the ultrasonic wave into the fluid in the stent and reception of the echo. Also, by carrying out a predefined number of transmit/receive cycles for the given transducer 44-46 that has been selected by theMUX 38 and averaging the results, a more accurate estimate of fluid velocity through the stent can be obtained than by using only a single transmission and reception of an ultrasonic wave. Since the signal required to instruct the RF decode/control section 66 to change to the next transducer 44-46 is only required after the predefined number of cycles has been completed, the data gathering efficiency of the implantable electronic circuit is improved. - As noted above, the transducers 44-46 shown in
FIGS. 1 through 5 need not be ultrasonic transducers;FIG. 6 illustrates an electronic circuit that is particularly applicable for use with transducers 44-46 comprising pressure sensors. Silicon pressure sensors designed to be installed on the radial artery are available from the Advanced Technologies Division of SRI of Palo Alto, Calif. Such pressure sensors could be disposed within the wall of a stent to sense the pressure of fluid flowing through the stent at one or more points. TheMUX 38 is used for selecting a specific pressure transducer to provide a data signal that is transmitted to the outside environment via theRF coupling coil 30. In the implantable electronic circuit shown inFIG. 6 , a modulator/transmitter (MOD/XMTR) 70 receives the signal from the transducer 44-46 selected by theMUX 38 in response to the MUX selection signal provided over theMUX control lines 56 from the RF decode/control section 66 and, using the signal, modulates a RF signal that is supplied to theRF coupling coil 30. The RF signal transmitted by theRF coupling coil 30 thus conveys the data signal indicating pressure sensed by the selected transducer 44-46. In many cases, it will be preferable to monitor the pressure at the upstream and downstream ends of a stent in order to enable the differential pressure between these ends to be determined. This differential pressure is indicative of the extent to which any blockage in the lumen of the stent is impeding fluid flowing through the lumen. In most cases, parameters such as fluid flow or velocity are better indicators of the status of flow through the stent. - RF Coupling Coil and External Coil Embodiments
-
FIGS. 7 through 12 illustrate details of several different embodiments for theRF coupling coil 30 that is part of the stent implanted within a patient's body. TheRF coupling coil 30 is for receiving RF energy to provide power for the implantable electronic circuits ofFIGS. 1 through 6 and for transmitting data relating to the condition of flow and/or other parameter(s) sensed by transducers coupled to one or more stents that have been installed within the patient's vascular system. Optimization of RF coupling between theRF coupling coil 30 on the stent and an external coil is partially dependent upon the propagation characteristics of the human body. Since body tissue is largely water, the relative dielectric constant of mammalian soft tissues is approximately equal to that of water, ie., about 80. Also, the permeability of body tissue is approximately equal to one, ie., about that of free space. The velocity of propagation of a RF signal through the body is proportional to the inverse square root of the dielectric constant and is therefore about 11% of the velocity of the signal in free space. This lower velocity reduces the wavelength of the RF signal by an equivalent factor. Accordingly, the wavelength of the RF signal transferred between the implanted RF coupling coil on a stent and the external coil would be a design consideration if the separation distance between the two is approximately equal to or greater than one-quarter wavelength. However, at the frequencies that are of greatest interest in the present invention, one-quarter wavelength of the RF coupling signal should be substantially greater than the separation distance between theRF coupling coil 30 on the stent and the external coil. - One method for optimizing coupling between an implanted coil and a coil that is external to the body is described in High-Efficiency Coupling-Insensitive Transcutaneous Power And Data Transmission Via An Inductive Link by C. M. Zierhofer and E. S. Hochmair, IEEE Trans. Biomed. Eng., Vol. 37, No. 7, July 1990, pp. 716-722. This approach allows the frequency of the signal linking the implanted and external coils to vary in response to the degree of coupling between the two coils. Other methods are suitable for coupling signals between the two coils as well.
- When the implantable electronic circuit includes the
RF coupling coil 30 and a transducer 44-46, but does not include active electronic circuitry, the external system (e.g., external power supply and patient monitoring console 100,FIG. 8 , below) senses a parameter related to the electrical input impedance of the external coil. When the external and internal coils are aligned, the inductance and the resistance of the external coil are maximized. The frequency of the signal that is used for adjusting the alignment may be different than the frequency that is used to provide electrical signals to the transducer. - The implantable electronic circuit may include an additional component to facilitate sensing of alignment between the two coils. For example, a metal disc in the implant may be detected and localized by inducing an eddy current in the disc. The external power supply and patient monitoring console may then detect the magnetic field generated by the eddy current in the disc, much as a metal detector operates. Using different frequencies for the location and therapeutic functions may avoid energy losses caused by the eddy currents.
- When the implantable electronic circuitry does include active electronic circuitry, a circuit may be included with the therapeutic transducer and RF coupling coil that measures the amplitude of the signal from the external power supply and patient monitoring console that is induced in the RF coupling coil. A signal is transmitted from the implantable electronic circuitry to the external power supply and patient monitoring console, where a display provides an indication of the coupling. The operator may adjust the position of the external coil to optimize coupling between the two coils.
- The penetration of RF fields in the human body has been studied extensively in conjunction with magnetic resonance imaging (MRI) systems. RF attenuation increases with frequency, but frequencies as high as 63 MHz are routinely used for whole-body imaging, although some attenuation is observed at the center of the torso at this upper frequency limit. In addition, MRI safety studies have also provided a basis for determining safe operating limits for the RF excitation that define the amplitude of excitation safely applied without harm to the patient.
- It is contemplated that for stent implants placed deep within the torso of a patient, RF excitation and frequencies used for communicating data related to the fluid flow through a stent and/or other parameters sensed proximate the stent can be up to about 40 MHz, although higher frequencies up to as much as 100 MHz may be feasible. At 40 MHz, the wavelength of the RF excitation signal in tissue is about 82 cm, which is just that point where wavelength considerations become an important consideration. For shallow implants, RF excitation at a much higher frequency may be feasible. For example, to provide energy to stents that are disposed within a blood vessel only a few millimeters below the epidermis and to receive data from transducers associated with such stents, excitation frequencies in the range of a few hundred MHz may be useful. The dielectric properties of tissue have been studied to at least 10 GHz by R. Pethig, Dielectric and Electronic Properties of Biological Materials, Wiley Press, Chichester, 1979 (Chapter 7). Based on this study, no penetration problems are anticipated in the frequency range of interest. The relative dielectric constant of tissue decreases to about 60 at a frequency of 100 MHz and is about 50 at 1 GHz, but this parameter has little effect on power/data signal coupling.
- An
external coil 90 and aRF coupling coil 30A shown inFIG. 7 represent one embodiment of each of these components that can be used for coupling electrical energy and conveying data signals across askin interface 102 for applications in which theRF coupling coil 30A is implanted relatively close to thesurface 102 of the skin. For example, theRF coupling coil 30A and theexternal coil 90 may provide, viamagnetic flux lines 112, the coupling required for a system used to monitor a stent implanted in an artery near theskin surface 102. A winding 92 is wrapped around acore 94 forming theexternal coil 90 and each end of the winding 92 is coupled to a power source through acable 98. - Although the
external coil 90 and theRF coupling coil 30A need not be identical in size, it is generally true that coupling will be optimal if the two devices are of approximately the same dimensions and if the longitudinal axis of theexternal coil 90 is generally adjacent and parallel to that of theRF coupling coil 30A. By observing the strength of the signal transmitted from theRF coupling coil 30A, it should be possible to position theexternal coil 90 in proper alignment with theRF coupling coil 30A so that the efficiency of the magnetic coupling between the two is optimized. - To function as the
core 94 for theexternal coil 90, the material used should have a relatively high magnetic permeability, at least greater than one. Although ferrite is commonly used for core materials, sintered powdered iron and other alloys can also be used. Since the magnetic characteristics of such materials are generally conventional, further details of theexternal coil 90 and the core 94 are not provided. - A
housing 96 on theexternal coil 90 provides RF shielding against electromagnetic interference (EMI). In one embodiment, thehousing 96 for theexternal coil 90 is conductive, grounded and surrounds theexternal coil 90 except where the surfaces of the generally “C-shaped”core 94 are opposite theRF coupling coil 30A. The RF shield comprising thehousing 96 is attached to aninternal braided shield 99 of thecable 98. Inside the power supply and patient monitoring console (not shown inFIG. 7 ) to which thecable 98 is coupled, theshield 99 is connected to ground. The RF shield on theexternal coil 90, along with shields provided around transducers 44-46 on thestent 106, minimizes external EMI radiation due to the use of the present invention within a patient's body. - For the embodiment shown in
FIG. 7 , theexternal coil 90 is magnetically coupled to a spiral winding 108 in thestent 106 that is implanted in ablood vessel 107. The spiral winding 108 comprises theRF coupling coil 30A for thestent 106 and the opposite ends of the spiral winding 108 are coupled to anelectronic circuit 110, which may comprise any of the implantable electronic circuits described above in connection withFIGS. 1 through 6 . Not shown inFIG. 7 are the one or more transducers 44-46 that are included within thestent 106 to monitor one or more parameters. - The
RF coupling coil 30A used in thestent 106 may be either an integral part of thestent 106, or it may instead comprise a separateRF coupling coil 30A that is wound around or through the structure comprising the wall of thestent 106. To function within the body of a patient, thestent 106 must be able to bend and flex with movement of the body, yet must have sufficient surface area and hoop strength to compress the atheriosclerotic material that is inside the blood vessel wall radially outward and to support the vessel wall, maintaining the lumen cross section. Several manufacturers offer stent designs, each fabricated from wire, bent back and forth in a periodically repeating “S” shape or zigzag configuration, forming a generally cylindrical tube. Such stents are considered ideal for use in practicing the present invention, since the wire comprising the wall of thestent 106 can be used for theRF coupling coil 30A. Examples of such stents are the ANGIOSTENT stent made by AngioDynamics, the stent sold by Cordis Corporation, the CARDIOCOIL stent produced by Instent and the WIKTOR stent from Medtronic Corporation. -
FIG. 8 illustrates another embodiment in which an implantedcoil 90A disposed outside theblood vessel 107 adjacent to an implantedstent 106A is electromagnetically coupled throughmagnetic flux lines 112 to thestent 106A using a plurality of electrically isolated and separatehelical windings stent 106A. Not shown are the implantable electronic circuitry and the transducers 44-46 that are coupled to the windings comprising aRF coupling coil 30B, however, it will be understood that any of the implantable electronic circuits shown inFIGS. 1 through 6 , discussed above, can be used for this purpose. However, by using electrically isolated andseparate windings 109A-E for theRF coupling coil 30B, it is possible to avoid multiplexing the signals from each different transducer 44-46 used in thestent 106A, since each transducer 44-46 (or sets of transducers 44-46) can transmit data over its own winding and separately receive an excitation signal from the implantedcoil 90A. This figure shows the implantedcoil 90A coupled to an external power source and monitor through acable 98A. Thecable 98A can either penetrate the dermal layer of the patient's body, passing to the outside environment, or alternatively, may itself be electromagnetically coupled to an external coil, such as theexternal coil 90 shown inFIG. 7 . When thecable 98A from the implantedcoil 90A penetrates thedermal layer 102, it is likely that the parameters being sensed by thestent 106A will only need to be monitored for a relatively short time, so that the implantedcoil 90A can be removed from the patient's body after the need to monitor the parameters is satisfied. An advantage of the embodiment shown inFIG. 8 is that when thestent 106A is implanted deep within the patient's body, it can be readily energized and the data that it provides can be more efficiently received outside the body by using the implantedcoil 90A as an interface, either directly coupled through theskin 102 or magnetically coupled through an external coil. - Stents comprising a woven mesh of fine helical wires are available from certain stent manufacturers. The woven mesh provides the required hoop strength needed to support the wall of a blood vessel after the stent is implanted and expanded or allowed to expand. To maintain the required flexibility for the stent, the wires comprising the woven mesh of such stents are not joined at the intersection points. An example is the WALLSTENT stent, which is sold by Medivent-Schneider. This configuration is also well suited for practicing the present invention. To be used as the
RF coupling coil 30B, the wires forming the body or wall of thestent 106A must be electrically insulated from the surrounding tissue of theblood vessel 107 and must be insulated from each other where they cross except at any node wherein the helical turns are linked to form one or more sets of coupled turns. The wire used for this configuration can be either round or flat. - An embodiment of a
RF coupling coil 30C comprising astent 106B is shown inFIG. 9 to illustrate the configuration discussed above. TheRF coupling coil 30C comprises awoven mesh 132 fabricated from insulated wire so that overlapping segments of the wovenmesh 132 do not electrically connect in the center of thestent 106B. At each end of theRF coupling coil 30C, the wires comprising the wovenmesh 132 are electrically coupled together atnodes 134, producing theRF coupling coil 30C. Thenodes 134 are insulated from contact with body fluids or other conductors. - The couplings at the
nodes 134 are preferably not made randomly or in a haphazard fashion between the various wires comprising the wovenmesh 132. A first wire comprising a helical coil having, e.g., a first configuration (which may be called a “right hand spiral” or RHS) has a first end coupled to a first end of a second wire comprising a helical coil having a second configuration (“left hand spiral” or LHS; i.e., a mirror image of the right hand spiral). The voltage induced in the two wires is equal, but opposite in sign, and the two wires are thus coupled in series and provide twice the voltage between their second ends than that produced between the first and second ends of either wire alone. Accordingly, the second ends of the first two wires cannot be coupled together at the other end of the wovenmesh 132 if these two wires are to contribute to the total electrical energy derived from the wovenmesh 132. Rather, the wires must be “daisy chained” in series (i.e., RHS-LHS-RHS-LHS etc.) to provide one embodiment of theRF coupling coil 30C. Alternatively, a first group of wires all having the right hand spiral may all be coupled in parallel (i.e., have the ends at a first end of the wovenmesh 132 coupled together, and the ends at a second end of the wovenmesh 132 coupled together), with wires having the left hand spiral being similarly treated but in a second group. The groups then may be combined in series or in parallel, or subsets of the wires may be grouped and combined. - When each wire comprising the woven
mesh 132 passes around the central axis of thestent 106B through m degrees, and if there are a total of n such wires, then the equivalent number of turns in theRF coupling coil 30C is equal to n×m÷360.Leads nodes 134, coupling the wovenmesh 132 to the implantableelectronic circuit 110, which may comprise any of the implantable electronic circuits ofFIGS. 1 through 6 . - The woven mesh structure of the implantable
RF coupling coil 30C is often used for stents. However, it should be noted that currently available woven mesh stents are not woven from insulated wire, nor are the nodes of the mesh at each end electrically connected in commercially available stents. In the WALLSTENT stent by Medivent-Schneider, the ends are instead free floating. It is also contemplated that an insulated electrical conductor could be woven into the structure of a commercially available mesh stent. Alternatively, theRF coupling coil 30C could be fabricated from a woven mesh or from a plurality of spiral turns of a conductor and then the mechanical characteristics required of the stent could be achieved by providing an interwoven wire within theRF coupling coil 30C. It is also noted that different implantable electronic circuits can be coupled to separate portions of the wovenmesh 132 comprising theRF coupling coil 30C so that the different portions of theRF coupling coil 30C and the implantable electronic circuits are electrically isolated from each other, or as a further alternative, the sections can be coupled in series. - In
FIG. 10 , aRF coupling coil 30D in a stent 106C is illustrated that comprises a plurality of generally saddle-shaped coils 114 disposed within (or comprising) the wall of the stent 106C. Again, theRF coupling coil 30D is coupled to the implantableelectronic circuit 110. Although only a single layer of saddle-shaped coils 114 is illustrated, it is contemplated that a plurality of such interconnected layers could be provided for the stent 106C. - For use in electromagnetically coupling with the
RF coupling coil 30D to energize the implantableelectronic circuit 110 and to provide signals to and receive data from the transducers 44-46 (not separately shown) on the stent 106C, anexternal coil 90B is provided that includes a plurality ofcoils 92B wrapped around a central portion of a generallyE-shaped core 94B. Lines ofelectromagnetic flux 112 are thus produced between the central leg and each of the end legs of the core 94B. It will therefore be apparent that this embodiment of theRF coupling coil 30D and of theexternal coil 90B achieves optimum coupling when the distance separating the two is minimal. Therefore, theRF coupling coil 30D and theexternal coil 90B are best used in applications where the stent 106C is disposed relatively close to thedermal layer 102 so thattissue 104 separating the stent 106C from theexternal coil 90B is only a few centimeters thick. Maximal coupling is achieved when the central axis of theexternal coil 90B is aligned with the central axis of the coil mounted on the stent 106C. -
FIG. 11A illustrates an embodiment of aRF coupling coil 121 that is helically coiled around the circumference of a stent fabricated by slotting ametal tube 116. The insulated conductor comprising theRF coupling coil 121 is kinked (or fan-folded) when wound around themetal tube 116 to accommodate expansion of themetal tube 116 once implanted in a blood vessel. The insulation on theRF coupling coil 121 prevents the turns from electrically shorting by contact with themetal tube 116 or with surrounding tissue. Although not shown, theRF coupling coil 121 will likely be adhesively attached to themetal tube 116 at several spaced-apart locations. The ends of theRF coupling coil 121 are coupled to one or more transducers or sensors 44-46 (not shown) through an implantable electronic circuit (also not shown) comprising any of the implantable electronic circuits shown inFIGS. 1 through 6 . - The
metal tube 116 includes a plurality of generally longitudinally extendingslots 117 at spaced-apart locations around the circumference of the stent. Theseslots 117 provide the expansibility and flexibility required of the stent. This design is similar to the Palmaz-Schatz stent made by Johnson & Johnson Corporation. To avoid providing a shorted turn with the body of themetal tube 116, the generally conventional design of the stent is modified to include abreak 118 extending along the entire length of themetal tube 116. The edges of themetal tube 116 are coupled atseveral joints 119 along thebreak 118 using a non-conductive material. - Metal-to-ceramic (or metal-to-glass) welded
joints 119 are commonly employed in medical implants and other electrical devices. To minimize thermal stress in the joint 119, the metal and the glass or ceramic must have similar thermal expansion coefficients. For example, KOVAR™ alloy, a nickel-iron alloy (29% Ni, 17% Co, 0.3% Mn and the balance Fe) is one material that can be used to form glass to metal seals that can be thermally cycled without damage. This material can be used to form portions of themetal tube 116 disposed along thebreak 118. Glass or ceramic bonds comprising thejoints 119 then will not experience much thermal stress when the temperature of the stent changes. This material is commonly used in lids that are bonded onto ceramic chip carriers in the integrated circuit industry and thus is readily available. - An alternative design for a stent formed from a
non-woven wire 145 about which theRF coupling coil 121 is coiled is illustrated inFIG. 11B . TheRF coupling coil 121 is again formed of an insulated conductor that is helically coiled about the circumference of the stent. The body of the stent comprises a plurality of zigzag shapes formed ofwire 145 that are joined by non-conductive (i.e., glass or ceramic) joints 146 at spaced-apart points that prevent thewires 145 from forming any shorted turns. This stent configuration is similar to that of the ACS RX MULTI-LINK stent made by Medtronic and the GFX (AVE) stent produced by Arterial Vascular Engineering. - In those cases where stents are implanted relatively deeply inside the patient's body, at some distance from the surface of the patient's skin, an alternative
external coil 154 can be employed, generally as shown inFIG. 12 . In this example, astent 144 comprising theRF coupling coil 30C (FIG. 9 ) is implanted within anartery 152, which is disposed within athigh 150 of the patient. Alternatively, thestent 144 may be implanted, for example, in the descending aorta, the iliac arteries or to provide therapy to a tumor that is deeply within the abdomen. To couple with theRF coupling coil 30C, theexternal coil 154 includes a plurality ofturns 156 sufficient in diameter to encompass thethigh 150. ARF shield 160 encloses the outer extent of theexternal coil 154, so theexternal coil 154 is insensitive to capacitively coupled noise. A lead 158 couples theexternal coil 154 to a power supply andmonitoring console 101. Theexternal coil 154 can be made sufficiently large to encompass the portion of the body in which the implantedstent 144 is disposed such as the torso, a limb of the patient, or the neck of the patient. Coupling is maximized between theexternal coil 154 and theRF coupling coil 30C (or other RF coupling coil) used on thestent 144 when the central axes of both theRF coupling coil 30C and theexternal coil 154 are coaxially aligned and when the implantedstent 144 is generally near the center of theexternal coil 154. Coupling between theRF coupling coil 30C and theexternal coil 154 decreases with increasing separation and begins to degrade significantly when the implantedstent 144 is more than oneexternal coil 154 radius away from the center point of theexternal coil 154. In addition, coupling is minimized when the central axis of theexternal coil 154 is perpendicular to the axis of theRF coupling coil 30C. - Description of the Diagnostic Applications of Transducers
- An ultrasonic transducer for monitoring flow or fluid velocity through a stent should be relatively compact and included in or mounted on the wall of a stent. Typical prior art ultrasonic transducers include a planar slab of a piezoelectric material having conductive electrodes disposed on opposite sides thereof. Since such elements are planar, they do not conform to the circular cross-sectional shape of a stent. Moreover, prior art transducers are not compatible for use with a stent that is implanted within a patient's body and which is intended to be left in place for an extended period of time. Also, it is apparent that conventional ultrasonic transducer elements will not readily yield to being deformed into a compact state for implacement within a blood vessel, followed by expansion of a stent body to apply radially outwardly directed force to compress the deposits within a blood vessel.
-
FIGS. 13 through 15 show an embodiment of an extremely low profile ultrasonic transducer comprisingconformal transducer arrays stent 168. While theconformal transducer arrays conformal transducer arrays stent 168 are not illustrated. Instead, only a portion of itsoutline 170 is shown. Ideally, eachconformal transducer array stent 168 when thestent 168 is inserted through the patient's vascular system and to flex as thestent 168 is expanded within a blood vessel. - When used for transit time measurements, as shown in
FIGS. 13 and 14 , theconformal transducer arrays stent 168 and encompass much of the inner circumference of thestent 168. However, when a pulsed Doppler measurement is made using theconformal array transducer 174A, only a single suchconformal array transducer 174A is required, since theconformal array transducer 174A first produces an ultrasonic wave that is transmitted into the lumen of thestent 168 and then receives an echo reflected back from the fluid flowing through thestent 168. If used for continuous wave (CW) Doppler measurements, the pair ofconformal transducer arrays stent 168 are again needed, oneconformal transducer array conformal transducer array - The
conformal transducer arrays FIGS. 13 through 15 produceultrasonic beams 178 that are tilted relative to the transverse direction across thestent 168 in substantially equal but opposite angles with respect to the longitudinal axis of thestent 168. Since dual beam transit time measurements are implemented by theconformal transducer arrays conformal transducer arrays stent 168 may be imperfect. For transit time measurements made onstents 168 wherein the alignment of theconformal transducer arrays stent 168 remains accurately known, an opposed pair ofconformal transducer arrays stent 168 is sufficient so that the added complexity of the dual beam transducer geometry is not required for self compensation. - In the case of pulsed Doppler velocity measurements, a single
conformal transducer array 174A would again likely be adequate so long as the alignment of theconformal transducer array 174A to thestent 168 is accurately controlled. If the alignment of theconformal array transducer 174A is not controlled or not well known, a second suchconformal transducer array 174B can be used to gather velocity data along a second beam axis using pulsed Doppler velocity measurements. Assuming that the second axis is tilted in an equal but opposite direction as the first axis, the Doppler measurements made by the twoconformal transducer arrays conformal transducer array 174B could be mounted on the same or on an opposite side of the stent from that where the firstconformal transducer array 174A is mounted to implement the Doppler measurements. - For CW or pseudo-CW Doppler velocity measurements (in which a relatively long duration pulse of ultrasonic waves is produced), the transit signal is applied for a sufficiently long period so that a second
conformal transducer array 174B is needed to receive the echo signals. In this case, a single set of diametrically opposedconformal transducer arrays - As perhaps best illustrated in
FIG. 14 , theconformal transducer arrays stent 168. In the illustrated embodiment, theconformal transducer arrays circular stent 168 as shown inFIG. 14 ). This geometry produces a measurement zone through whichultrasonic beams 178 propagate that is nominally equal to about 50% of the outer diameter of thestent 168. If used for Doppler velocity measurements, it is contemplated that theconformal transducer array 174A need cover only a central portion of thestent 168. As a result, the span of theconformal transducer arrays - To produce a wide, uniform ultrasonic beam such as that needed for transit time measurements of flow, the
conformal transducer arrays FIG. 13 , lateral projections through each of a plurality of transducer elements comprising theconformal transducer arrays straight lines 176. Thesestraight lines 176 indicate the centers of the transducer elements and are perpendicular to the axis of propagation of waves 178 (represented by bi-directional arrows directed along the axes of propagation of the ultrasonic waves). In one embodiment, the spacing between the element centers, i.e., between thestraight lines 176, is approximately equal to a phase angle of 90° at the excitation frequency of theconformal transducer arrays FIG. 13 and working downwardly, transducer elements disposed along each of the displayedstraight lines 176 produce acoustic waves that are successively delayed by 90°, or one-quarter wavelength in the fluid medium through which the ultrasonic waves propagate. For tissue, a sound velocity of 1,540 meters/second is normally assumed, so that the physical spacing of the projected straight lines would typically be defined by the following:
Projected Spacing in millimeters=1.54/(4*F 0),
where F0 is equal to the center frequency in MHz. If zero degrees is assigned to the top-most element of theconformal transducer array 174A, the next element would operate at −90° relative to the top element, followed by an element operating at −180°, and then one operating at −270°, and finally by an element operating at 0° relative to the top electrode. Thus, theconformal transducer array 174A produces a succession of ultrasonic waves spaced apart by a 90° phase shift, thereby achieving a desired phase uniformity across theconformal transducer array 174A. - While the discussion herein is in terms of phase shifts of 90°, it will be appreciated that other types of transducer element spacings or relative displacements may require different phase shifts. For example, three phase transducers are known that employ a phase shift of 120° between adjacent elements. Additionally, physical displacements of the transducer elements in the direction of propagation of the acoustic waves may require different or additional phase shifts between the electrical signals coupled to the elements. It is possible to phase shift these signals to provide a uniform phase front in the propagating acoustic wave using conventional techniques.
- Amplitude uniformity can be achieved in the ultrasonic wave front by apodization or “shaving” of the elements of the
conformal transducer arrays - In one embodiment, the
conformal transducer arrays band 172 made from the piezoelectric plastic material used for the element substrate, which is sized to fit snugly around an outer surface of thestent 168 or inserted into the lumen of the stent 168 (as shown inFIG. 14 ). Theband 172 is intended to position theconformal transducer arrays stent 168, when theband 172 is wrapped around thestent 168, or to maintain theconformal transducer arrays stent 168, when theband 172 is inserted into the lumen of thestent 168. Contact of theband 172 around the outer surface of thestent 168 assures that the ultrasonic waves produced by the elements of theconformal transducer arrays band 172 is fabricated from a material such as polyvinylidene fluoride (PVDF), poly(vinyl cyanide-vinyl acetate) copolymer (P(VCN/VAc), or poly(vinylidene fluoride-trifluoroethylene) copolymer (P(VDF-TrFE)), available from AMP Sensors of Valley Forge, Pa. In one embodiment, P(VDF-TrFE) is used because of its high piezoelectric coupling and relatively low losses. - Referring now to
FIG. 15 , further details of theconformal transducer arrays conformal transducer arrays FIG. 15 , acut line 175 intersects the lateral center of theconformal transducer array 174B. In practice, any cut would more likely extend through theband 172 at a point approximately midway between theconformal transducer array 174A and theconformal transducer array 174B. Electrodes comprising each element of theconformal transducer arrays band 172. Alternatively, the elements can be formed on a non-piezoelectric material comprising theband 172, and then the material with the elements formed thereon can be bonded to a piezoelectric substrate in each area where a conformal array transducer element is disposed. In this latter embodiment, it is contemplated that a flexible circuit material such as a polyimide could be employed for theband 172 and that conventional photolithographic processing methods might be used to fabricate the conformal array transducer circuitry on theband 172. Further, the centers of alternating conformal array elements are coupled together electrically via conductors 180 (shown as dashed lines) inFIG. 15 . Not shown inFIGS. 13 through 15 are the leads that extend from an implantable electronic circuit used to drive theconformal transducer arrays FIGS. 1 through 6 could be used for the implantable electronic circuits. - The pattern of elements comprising each of the
conformal transducer arrays conformal transducer array FIG. 15 ), define sinusoidal segments. The period of the sine wave from which these sinusoidal segments are derived is approximately equal to the circumference of theband 172. Further, the amplitude of that sine wave generally depends on the desired beam angle relative to the longitudinal axis of the stent. For the sinusoidal segment employed for each electrode, the amplitude is defmed by:
Amplitude=D*tan Θ. - Similarly, the amplitude of the sinusoidal segment defining the boundary of each
conformal array
Amplitude=D/(tan Θ),
where Θ is equal to the angle between the longitudinal axis of the stent 168 (seeFIG. 13 ) and theultrasound beam axis 178 and D is equal to the external diameter of thestent 168. Accordingly, it should be apparent that one sinusoidal template could be used to draw all of the transducer elements and a second sinusoidal template (differing only in amplitude from the first) could be used to draw the boundary of eachconformal array transducer FIG. 13 . In addition, the actual physical electrode pattern and placement of the elements on theband 172 can be determined by finding intersection loci between theband 172 as wrapped around (or within the inner circumference of) thestent 168 and equally-spaced planes. The spacing between these planes is defined by the equation noted above for the projected spacing. - The
conductors 180 that couple to adjacent transducer elements differ in phase by 90°. There are two ways to achieve the 90° phase variation between the ultrasonic waves produced by successive electrodes in theconformal transducer arrays FIG. 15 ). Each of these two groups is then coupled to provide an in phase and a quadrature phase transceiving system, so that ultrasonic waves are produced by adjacent elements in each group have a relative phase relationship of 0° and 90°. In the first approach, a multi-layer interconnect pattern is required to couple to all traces for each of the transducer elements in the four groups. In addition, a more complex four-phase electronic driving system that includes a phase shifter is required. Specifically, the signal applied to each of the four groups must differ by 90° between successive elements to achieve the 0°, 90°, 180° and 270° driving signals. The phase shifter, e.g., may be included in the modulator that drives theconformal transducer arrays RF decode section 40 ofFIGS. 1 through 3 or the RF decode/control section 66 ofFIGS. 4 through 6 ), and provides the phase shifted excitation signals applied to each successive element of theconformal transducer arrays - In the second approach, which may be preferred in some embodiments because it may simplify the electronic package required and because it may facilitate use of a simpler, double-sided electrode pattern, the piezoelectric plastic material must be locally poled in a specific direction, depending upon the desired phase of the electrode at that location. A poling direction reversal provides a 180° phase shift, eliminating the need for 180° and 270° phase-shifted signals. Thus, the zones of the substrate designated as 0° and 90° would be connected to the in-phase and quadrature signal sources with the elements poled in one direction, while zones for elements designated to provide a relative phase shift of 180° and 270° would be connected to the in-phase and quadrature signal sources with the elements poled in the opposite direction. The elements producing ultrasonic waves with a relative phase relationship of 0° and 180° would comprise one group (e.g., in-phase) and the elements producing ultrasonic waves with a relative phase relationship of 90° and 270° would comprise a second group (e.g., quadrature). Poling the different groups of elements in local regions in opposite directions is achieved by heating the material above the Curie temperature, applying electric fields of the desired polarities to each of those areas and then cooling the material below the Curie temperature while maintaining the electric fields. This occurs during manufacture of the
conformal transducer arrays conformal transducer arrays vessel 170 would preclude applying electric fields in opposite polarity. Accordingly, the required poling relationship would have to be performed using either temporary electrodes or by providing temporary breaks in the actual electrode pattern employed in the finalconformal transducer arrays - In one embodiment, to achieve a desired frequency of operation, it is contemplated that the electrode mass would be increased to a point well beyond that required for making electrical connections. This added mass would act together with the piezoelectric plastic material to form a physically resonant system at a desired frequency. In this manner, a relatively thinner and more flexible piezoelectric plastic material can be used for the substrate comprising the
band 172. Use of mass loading is conventional in the art of ultrasonic transducer design. - While the fluids within the
vessel 170 may provide an effective ground plane, in one embodiment, a conductive layer 177 (seeFIG. 14 ) is included. Theconductive layer 177 may be disposed on the inside of theband 172 as illustrated (between theconformal array transducer 174A and the band 172). In one embodiment, theconformal array transducer 174A comprises a sandwich of two layers of piezoelectric plastic, with the driven electrodes disposed between the two layers of piezoelectric plastic, and ground planes disposed to either outside surface of theconformal array transducer 174A. The transducer then comprises a ground plane, a layer of piezoelectric plastic, a layer of driven electrodes, a layer of piezoelectric plastic and the other ground plane. This embodiment has the advantage that theconformal array transducer 174A is well shielded and further is electrically isolated from body fluids. Other arrangements will also be apparent to those of skill in the art. When theconformal transducer arrays conductive layer 177 may be floating (a “virtual ground”) or may be coupled to a ground or common circuit (e.g., 34,FIGS. 1 through 6 ). When theconformal transducer arrays conductive layer 177 should be coupled to a common circuit or ground to reduce noise and EMI. - In
FIGS. 16A and 16B , an alternative approach for monitoring the velocity of a fluid through an interior 250 of astent 240 is illustrated. A pair ofultrasonic transducers FIGS. 13 through 15 , or may be realized in other forms, and may find application as therapeutic transducers in addition to being useful as diagnostic transducers. - In the embodiment illustrated in
FIGS. 16A and 16B , the pair ofultrasonic transducers wall 244 of thestent 240. Alternatively, theultrasonic transducers ultrasonic transducers interior 250 of thestent 240, the echoes being scattered from the fluid flowing therein. In this embodiment, the signal received from theultrasonic transducer 242A in response to the echo is correlated with a similar signal from theultrasonic transducer 242B, resulting in a time delay estimate. The velocity of the fluid is then computed by dividing a distance between the center of theultrasonic transducer 242A and the center of theultrasonic transducer 242B by the time delay that was determined from the correlation analysis. This is explained in more detail as follows. - The interaction of the blood with the ultrasound, even when it is moving at constant velocity, gives rise to a moving acoustic “speckle” pattern. The term speckle, as used herein, has a similar meaning in ultrasonics as in optics. It results any time that narrow-band illumination is used. Optical speckle is visible when a laser (e.g., a pointer) illuminates a plain white wall. When illuminated with wideband illumination, the wall appears white and smooth. When illuminated with laser light, the wall appears to have bright and dark spots, hence the term speckle. Acoustic speckle is visible in medical ultrasound images, when the system is used to image homogeneous soft tissues such as the liver. As in optics, the acoustic speckle pattern is stationary and constant unless the tisse or flood is moving with respect to the imaging system. The same phenomenon is exploited in Doppler systems. When the echo return from moving blood is constant, there is no observable Doppler shift in the echo signal.
- The blood consists of thousands of scatterers, and the ultrasound reflects from ensembles of these scatterers. The amplitude and phase of the echo, at a given range, depends on the local distribution of scatterers, which is random. The random signal of echo amplitude and phase at a given depth repeats as the blood flows past the second
ultrasonic transducer 242B, if the spacing between the twoultrasonic transducers ultrasonic transducers ultrasonic transducers - In other words, the first
ultrasonic transducer 242A receives an echo signal that provides a speckle “image”—where the distance from theultrasonic transducer 242A is along the vertical dimension inFIGS. 16A and 16B , and the successive echo returns are along the horizontal dimension. The two “images” from the twoultrasonic transducers - The sampling aperture for this system is much shorter than the time required for a heartbeat. Accordingly, a series of measurements, which may be taken during the interval between two successive heartbeats, may be processed or compared to determine peak, minimum and average blood velocity when these data are desired.
- Unlike a Doppler system, the echoes in a correlation type transducer system like that shown in
FIGS. 16A and 16B are not frequency shifted. Instead, the velocity signal is extracted by correlating the echo amplitude versus time signals for a pair of range bins. The velocity versus time is independently determined for each range bin, resulting in a time dependent velocity profile across the diameter of thestent 240. - The
conformal transducer arrays FIGS. 13 through 15 can be formed on theband 172, but alternatively, can be included within the structure of a stent, i.e., within its wall.FIG. 17 illustrates a portion of a cross-sectional view of theconformal array transducer 174A ofFIGS. 13 through 15 fabricated in astent wall 190. The entireconformal array transducer 174A is fitted within thestent wall 190. Details of thestent wall 190 are not illustrated, since it is contemplated that many different types of stent configurations are suitable for carrying theconformal transducer arrays stent wall 190 is shown inside ablood vessel wall 204. A biocompatibleouter coating 192 comprises the next layer, protecting theconformal transducer arrays outer coating 192 comprises PARYLENE™ material, available from Specialty Coating Systems of Indianapolis, Ind.Outer coatings 192 comprising PARYLENE™ material may be grown to a desired thickness via vapor coating. In one embodiment, theouter coating 192 is grown to a thickness of between 0.0001″ to 0.0002″ (2.5 to 5 microns). Below theouter coating 192 is anacoustic backing 194 comprising a conventional, or a syntactic foam, i.e., a polymer loaded with hollow microspheres, that serves both for acoustic isolation and dampening and to minimize capacitive loading. - In one embodiment, the
acoustic backing 194 comprises one volume of EPOTEK 377 or 301-2 epoxy glue available from Epoxy Technology of Billerica, Mass. mixed, e.g., with two or more volumes of microballoons available from PQ Corp. of Parsippany, N.J. Microbubbles such as PM6545 acrylic balloons having an average diameter of 100 microns are employed in one embodiment, with the acoustic backing being 10 to 20 microballoons thick (one to two mm). Theacoustic backing 194 has a relatively low dielectric constant (e.g., <10), thereby minimizing capacitive loading between the electrodes and surrounding tissue. Theacoustic backing 194 thus insulates the transducer elements from the surrounding fluid and tissue in a capacitive sense and also in an acoustic sense. The next layer comprises arear electrode 196. Afront electrode 200 is spaced apart from the rear electrode by apiezoelectric plastic layer 198. In one embodiment, thefront electrode 200 is also theconductive layer 177 ofFIG. 14 . As noted above, in the embodiment illustrated inFIGS. 13 through 15 , thepiezoelectric plastic layer 198 ofFIG. 17 comprises theband 172 ofFIGS. 13 through 15 . The piezoelectric layer 198 (or the band 172) has a relatively low dielectric constant, e.g., from about six to eight, compared to tissue (approximately 80). - In one embodiment, the
rear electrode 196 and thefront electrode 200 comprise multi-layer structures (although separate layers are not shown). For example, theelectrodes piezoelectric plastic layer 198, for example, titanium, followed by a highly conductive layer, for example, copper, followed by an oxidation resistant layer, for example, gold, and includes other metallic barrier layers, where appropriate, to prevent reaction between these layers. Such multi-layer systems are conventional and are suited for use as theelectrodes conformal transducer arrays - In one embodiment, the
front electrode 200 is the “common electrode” for the transducer elements and serves as a RF shield. Afront coating 202 serves as an acoustic coupling between theconformal transducer arrays front coating layer 202 serves as a biocompatible layer, providing a barrier to fluid ingress into theconformal array transducers - In both the
conformal array transducers FIGS. 13 through 15 ) and theconformal array transducer 174A included within the structure of thestent wall 190, as illustrated inFIG. 17 , it is contemplated that adhesive layers (not shown) may be used between the various layers. However, certain layers such as the front andrear electrodes piezoelectric layer 198 if photolithographically formed on thepiezoelectric layer 198. Other layers may not require an adhesive to couple to adjacent layers, e.g., if formed of a thermoset material that self bonds to an adjacent layer when set. - As noted above, one of the advantages of the
conformal transducer arrays element transducer 210 coupled to astent 203 that is useful as a diagnostic transducer or as a therapeutic transducer is illustrated inFIG. 18 . Each element comprising the tiltedelement transducer 210 includes therear electrode 196 and thefront electrode 200 disposed on opposite sides of thepiezoelectric material 198. Conventional prior art transducers for producing an ultrasonic waves use a single such element that has a substantially greater width that is often too great for inclusion within a stent assembly. In contrast, the tiltedelement transducer 210 includes a plurality of elements like those shown inFIG. 18 that minimize the radial height (or thickness) of the tiltedelement transducer 210. - An
outer coating 195 again serves the function of providing a biocompatible layer to protect the transducer components contained therein from exposure to bodily fluids. When theouter coating 195 comprises PARYLENE alone, anRF shield 193 extends over the tilted elements, immediately inside theouter coating 195. When theouter coating 195 comprises a container (as illustrated), it includes an outer coating of a material such as PARYLENE. When theouter coating 195 comprises a conductive material, a separate RF shield such as theRF shield 193 may not be required. Theacoustic backing 194 is disposed below theRF shield 193 or theouter coating 195. - An
acoustic filler material 212 is disposed between thefront electrode 200 and thefront coating 202, on the interior surface of thestent 203, and is used to fill in the cavities in front of the transducer elements. Theacoustic filler material 212 is characterized by a relatively low ultrasonic attenuation, so that it readily conveys the ultrasonic waves produced by the transducer elements into the lumen of thestent 203. In one embodiment, in order to minimize reverberations of the ultrasonic waves in thisacoustic filler material 212, its acoustic impedance, which is related to sound velocity times density, is approximately equal to that of the fluid in the vessel. The velocity of sound in theacoustic filler material 212 should also be close to that of the fluid flowing through thestent 203 so that the sound beam is not significantly deflected by theacoustic filler material 212. In another embodiment, theacoustic filler material 212 has a relatively low sound velocity compared to the fluid. In this embodiment, theacoustic filler material 212 acts as an acoustic lens that deflects the sound being produced by the elements of the tiltedelement transducer 210. For example, materials such as silicones or fluorosilicones typically having sound velocities about 1000 meters per second (compared to a sound velocity of approximately 1540 meters per second for blood) may be used. Low velocity lenses are conventional. A benefit of using a low velocityacoustic filler material 212 is that the elements of the tiltedelement transducer 210 can be tilted about 30% less than would be required otherwise. As a result, the overall height of the tiltedelement transducer 210 portion of thestent 203 can be made about 30% thinner than would be possible without the low velocityacoustic filler material 212. In combination, the plurality of tilted elements of the tiltedelement transducer 210 produce anultrasonic wave 214 that propagates at an angle relative to the longitudinal axis of the stent, which is represented by acenter line 216 inFIG. 18 . -
FIG. 19A is an isometric view of an implantable integrated circuit (IC)transducer 220 mounted on atubular stent 222, which may comprise a stent similar to that described in conjunction withFIG. 11A above. Wires form aRF coupling coil 223 coupled to theimplantable IC sensor 220 viawires 225. The wires comprising theRF coupling coil 223 are formed in a zigzag shape to allow for expansion of thetubular stent 222 when it is installed. Theimplantable IC sensor 220 may include diagnostic or therapeutic transducers. In one embodiment, the sensing apparatus of theimplantable IC sensor 220 faces the interior of thetubular stent 222, as is described more fully with respect toFIG. 19B below. -
FIG. 19B illustrates theimplantable IC sensor 220 mounted on thetubular stent 222, so that theimplantable IC sensor 220 overlies asensor window opening 224 in thetubular stent 222. Conductive adhesive orsolder 228 couples theimplantable IC sensor 220 contacts to the tubular stent 222 (or to conductors that are coupled to one of the implantable electronic circuits shown inFIGS. 1 through 6 ). A biocompatible coating 226 (analogous to thebiocompatible coating 192 ofFIG. 17 ) encloses theimplantable IC sensor 220, except in the area of thesensor window opening 224 through which theimplantable IC sensor 220 is in contact with the fluid flowing through the lumen of thetubular stent 222. The portion of thetubular stent 222 on which theimplantable IC transducer 220 is mounted may be made rigid, e.g., by thickening it, to prevent damage to theimplantable IC transducer 220 during the installation of thetubular stent 222. Optionally, a circuit board (not illustrated inFIG. 19B ) may be included between theimplantable IC transducer 220 and thetubular stent 222 to facilitate making electrical interconnections to theRF coupling coil 223. -
FIG. 19C illustrates an embodiment wherein theimplantable IC transducer 220 is coupled to awoven mesh stent 222A. The wovenmesh stent 222A comprises wires woven to form a mesh comprising aRF coupling coil 223A as described in conjunction withFIGS. 8 and 9 above.Wires 225A couple theRF coupling coil 223A to theimplantable IC transducer 220. Theimplantable IC sensor 220 may include diagnostic transducers, and the wovenmesh stent 222A may include therapeutic transducers (not illustrated). In one embodiment, the sensing apparatus of theimplantable IC transducer 220 is held in place via anencapsulant 226A to face the interior of the wovenmesh stent 222A, as is described more fully with respect toFIG. 19D below. -
FIG. 19D is an enlarged partial cross-sectional side view of theimplantable IC transducer 220 mounted on the wovenmesh stent 222A of FIG. 19C. Theimplantable IC transducer 220 is coupled to the wires comprising the body of the wovenmesh stent 222A by theencapsulant 226A which may also serve as a biocompatible fluid barrier and as an insulator. This keeps theimplantable IC transducer 220 from contacting body fluids except at the sensing interface which is mounted within anopening 224A in the wall of the wovenmesh stent 222A. Aflexible circuit substrate 227 optionally is employed to provide mechanical attachment and electrical coupling to theimplantable IC transducer 220 via solder bumps 228 or other conductive and mechanically robust interconnection. In the embodiments ofFIGS. 19A through 19D , theimplantable IC transducer 220 may comprise the implantable electronic circuits of any ofFIGS. 1 through 6 and thestents - It is contemplated that the
implantable IC transducer 220 might be used for measuring parameters such as pressure, temperature, blood gas concentration and insulin level or the levels of other metabolite such as glucose or sodium in the blood stream of a patient in which a stent that includes theIC sensor 220 is implanted. As explained above, theimplantable IC sensor 220 is electrically energized with electrical power that is electromagnetically coupled to theRF coupling coil 223A that comprises thestent body 222A or which is incorporated as one or more separate insulated windings within the stent wall structure. Signals produced by theIC sensor 220 are converted to data signals, which are electromagnetically coupled to a monitor outside the patient's body, also as explained above. In certain applications ofimplantable IC sensors 220, it may be advantageous to perform a differential measurement between two spaced-apart locations on thestent body stent stent stent - If an external source of heat is applied to heat the blood or other fluid flowing through the lumen of a
stent IC sensors 220 that are responsive to that parameter. An external source of RF energy electromagnetically coupled into thestent stent stent - Other methods can be employed to determine flow based on temperature measurements. For example, by modulating the RF power used to heat the
stent stent - Several types of
IC sensors 220 that might be incorporated within a stent in accord with the present invention are disclosed in previously issued U.S. patents. For example, U.S. Pat. No. 4,020,830 (and re-examination certificate U.S. Pat. No. 4,020,830B1) entitled Selective Chemical Sensitive FET Transducers and U.S. Pat. No. 4,218,298 entitled Selective Chemical Sensitive FET Transducer describe chemical field effect transistor (FET) transducers that are sensitive to specific chemical substances or to their properties. U.S. Pat. No. 4,935,345 entitled Implantable Microelectronic Biochemical Sensor Incorporating Thin Film Thermopile discloses an implantable microelectronic biochemical sensor that incorporates a thin film thermopile for use in monitoring concentrations of glucose or other chemicals present in the blood stream. Various types of pressure sensing devices appropriate for incorporation in the wall of a graft are readily available from a number of different commercial sources, including SRI Center for Medical Technology of Palo Alto, Calif. - Other prior art devices are potential candidates for use as
IC sensors 220 onstents such IC sensors 220 are well known in the art and are generally available or readily fabricated for use onstents - In the embodiments of
FIGS. 19A through 19D , theimplantable sensor IC 220 senses the concentration of a particular substance or another parameter that was determined to require monitoring prior to implanting theimplantable sensor IC 220 or that is selected from a plurality of sensing capabilities provided on theimplantable sensor IC 220 in response to control signals coupled via theRF coupling coil FIGS. 13 through 15 , 17, 18, 20, 21 and 23 through 28. - A stent may include other types of sensors beside the ultrasonic transducers and the
IC sensor 220 noted above.FIG. 20 illustrates an outline of astent 232 that includes a strain sensor comprisingstrain sensing filaments 230 mounted on thestent 232. In the disclosed embodiment,strain sensing filaments 230 are wound around thestent 232 to measure displacement that is converted to a signal for transmission outside the body by animplantable IC 220A. Thefilaments 230 exhibit a change in electrical resistance with strain and are therefore usable to sense the strain experienced by thestent 232 when it is expanded inside a blood vessel. It is contemplated that thestrain sensing filaments 230 be used only for strain sensing, so that their dimension, disposition and metallurgy can be optimized for that function. Alternatively, thestrain sensing filaments 230 can comprise part of the structural body of thestent 232 so that they also provide a mechanical function related to the conventional function of thestent 232. It is also contemplated that strain gauges (not separately shown) can be used instead of thestrain sensing filaments 230. The strain gauges can be mounted to thestent 232 at selected spaced-apart locations to measure displacement. Metallized polyimide substrate strain gauges are suited to this application, by wrapping the substrates around the body of thestent 232 and attaching the substrates to the body of thestent 232 at selected spaced-apart points. By monitoring the size ofstent 232 as it is expanded, strain gauges or other strain measuring sensors can determine when a desired expansion of thestent 232 has been achieved. Alternatively, the strain data can be employed to assess the elasticity of thestent 232 and blood vessel structure by monitoring the dynamic strain over cardiac cycles, ie., with successive systolic and diastolic pressure levels. - Referring to
FIG. 21A , animplantable IC sensor 220B that detects fatty deposits and tissue growth inside the lumen of thestent 232 is illustrated as being disposed within the body of thestent 232, coupled to a pair ofdielectric sensing filaments 234. Theimplantable IC sensor 220B detects fatty deposits and tissue ingrowth within the lumen of the stent by measuring the dielectric and/or resistive properties of any material in contact with thesensing filaments 234, which are, e.g., helically coiled around the inner surface of thestent 232, from about one end of thestent 232 to its opposite longitudinal end. Alternatively, thesensing filaments 234 can be incorporated into the body or wall of thestent 232 itself. For example, when thestent 232 is fabricated with a woven mesh, a portion of the mesh can be utilized for making the dielectric and/or resistive measurement, while the remainder is used for a RF coupling coil. - In another embodiment, the
sensing filaments 234 may be spatially more limited to allow assessment of where blockage is occurring within thestent 232. A plurality oflocalized sensing filaments 234 may permit assessment of more than one area within thestent 232, by taking a series of measurements and communicating the results of the series of measurements to the attending physician. This may provide data relevant to determining what form of treatment is appropriate. - For measuring the dielectric properties, the
implantable IC sensor 220B is energized with power electromagnetically coupled from an external source into the RF coupling coil (not illustrated inFIG. 21A ) of thestent 232 and produces signals indicative of tissue ingrowth that are electromagnetically coupled to the external monitoring system through the RF coupling coil of thestent 232. In one embodiment, an RF signal at a frequency of from 10 to 100 MHz is applied to thesensing filaments 234. At such frequencies, tissue has the properties shown in the following Table 1.FIG. 21B illustrates an exemplary cross section of alumen 235 within thestent 232, showing the ingrowth offatty tissue 236, which is in contact with thesensing filaments 234.TABLE 1 Tissue Type Relative Permittivity Resistivity (Ohm-cm) Fat 6 to 20 2000 to 3000 Blood 80 to 160 80 to 90 Muscle 60 to 130 100 to 150 - The permittivity of tissue is closely related to its water content. Water has a relative permittivity of about 80. Since fat and fatty deposits of the type found inside blood vessels contain much less water than other tissue types, the permittivity of fat is much lower than that of muscle or blood. The wall of a blood vessel is muscular and highly perfused and will therefore have a much higher permittivity than a fatty deposit. Similarly, fatty deposits have a much higher resistivity than either blood or muscle. Therefore, a measurement of the dielectric and/or resistive properties of tissue inside the
stent 232 can differentiate fatty deposits from either blood or muscular tissue ingrowth into the lumen. The measurement can include a determination of capacitance, resistance or a combination of the two. - Further information can be obtained from the frequency dependence of the capacitance and resistance measured inside a stent lumen. For example, blood has a relatively flat resistivity vs. frequency characteristic curve, compared to that of muscle.
-
FIG. 22 illustrates a stent graft (or spring graft) 260 that includes embodiments of the present invention. Thestent graft 260 differs from a conventional synthetic graft in the method of delivery. Conventional grafts are installed surgically, whilestent grafts 260 are installed using an endovascular delivery system. Theentire stent graft 260 must be collapsible onto a delivery catheter (not shown). At a minimum, thestent graft 260 comprises a synthetic graft section 264 with anexpandable stent stents stent grafts 260 havestents - The
stent graft 260 is of a type that is used to repair arteries near a bifurcation of the artery into twosmall branches stent graft 260. The term “spring graft” is used with this type ofstent graft 260 because thestent portions stents Nitinol stents 262. Although a Nitinol stent is normally self-expanding, a balloon (not shown) may be included in the delivery system to perform one or more functions, including expansion of thestent 262, placement at the desired location, flow occlusion and straightening blood vessels to aid advancement of the assembly to the desired location. Electrically insulatingceramic joints 276 couple sections of eachstent insulated wire 272 is wound around the outside of the graft 264 and, in one embodiment, is formed of kinked or zigzag wire to enable expansion of the graft 264. Thewire 272 is coupled to a sensor/electronic circuit 274. Stent grafts suitable for use in the embodiment shown inFIG. 22 are made by Sulzer Vascutek and W. L. Gore. The ANEURX stent graft from Medtronic, and the WALLGRAFT stent graft from Medivent-Schneider, which includes a woven mesh stent within its wall, are also suitable for this embodiment. - Description of Therapeutic Transducers
- A variety of therapeutic transducers may be implanted that are responsive to and/or powered by the signals coupled into the implantable electronic circuits of
FIGS. 1 through 6 . One class of therapeutic transducers 44-46 provide utility by enabling localized delivery or activation of specific drugs for specific purposes. Two distinct applications where therapeutic transducers implanted within endoluminal implants provide therapeutic advantages are as adjunctive therapy and as primary therapy. - In adjunctive therapy, the therapeutic transducer is intended to realize localized drug activation and delivery in the vicinity of the stent or stent graft. This could be to maintain flow capability through the lumen by reducing restenosis due to new deposits of atherosclerotic material or to inhibit tissue ingrowth. Alternatively, in at least some cases, the same therapeutic transducer may aid in reducing thrombosis that is causing lumen blockage by activating appropriate drugs.
- In primary therapy, the stent with the therapeutic transducer is implanted specifically to provide local drug activation and delivery to tissue in the vicinity of and downstream from the stent. For example, a stent could be implanted in an artery that feeds blood to a tumor site. Systemically administered chemotherapeutic agents that are not toxic until activated may be activated during passage through the stent by energy provided by the therapeutic transducer. The blood containing the activated drug then proceeds downstream to the tumor site to locally administer the activated drug. This approach can provide significantly greater drug concentrations at the tumor site than are obtained systemically. Similarly, other drugs used to treat a variety of diseases may be locally activated at the region of interest. In some cases, modified genetic material may be locally concentrated in response to therapeutic transducer activation.
- One advantage to localized activation or delivery of drugs is that the side effects associated with the drugs may be reduced by only providing the drug at the site requiring treatment. This is advantageous in many situations, including chemotherapy, where the drugs are toxic or may have other potentially detrimental side effects.
- For example, drug activation phenomena have been reported using ultrasound to break precursor substances down into drug molecules and other by-products. In this case, one or more of the transducers 44-46 of
FIGS. 1 through 6 are ultrasonic transducers, several of which are described with respect toFIGS. 13 through 18 . Sonochemical activation of hematoporphyrin for tumor treatment is described by S. I. Umemura et al. in Sonodynamic Activation of Hematoporphyrin: A Potential Modality For Tumor Treatment, published in the 1989 IEEE Ultrasonics Symposium Proceedings, IEEE cat. no. 0090-5607/89/0000-0955, pp. 955-960. Ultrasonic potentiation of adriamycin using pulsed ultrasound is described by G. H. Harrison et al. in Effect Of Ultrasonic Exposure Time And Burst Frequency On The Enhancement Of Chemotherapy By Low-Level Ultrasound, published in the 1992 IEEE Ultrasonics Symposium Proceedings, IEEE cat. no. 1051-0117/92/0000-1245, pp. 1245-1248. Similarly, increased toxicity of dimethlyformamide has been reported in conjunction with ultrasound by R. J. Jeffers et al. in Enhanced Cytotoxicity Of Dimethylformamide By Ultrasound In Vitro, published in the 1992 IEEE Ultrasonics Symposium Proceedings, IEEE cat. no. 1051-0117/92/0000-1241, pp. 1241-1244. - Sonodynamic activation at one or more specific body sites to provide local drug delivery is possible when one or more of the transducers 44-46 of
FIGS. 1 through 6 are designed to provide suitable ultrasonic signals and are implanted at the locations where drug activation provides therapeutic benefits. Sonodynamic effects are nonlinear effects associated with the peak compression and expansion portions of the wave cycle; at lower frequencies, the time that the peak portions of the wave have to act is greater. For this reason, lower frequencies are preferred in some embodiments. Other embodiments increase peak forces by combining two or more ultrasonic waves. Several such transducers are described in connection withFIGS. 23 and 24 below. -
FIG. 23 illustrates anultrasonic transducer configuration 278 integrated with astent 279. Theultrasonic transducer configuration 278 is specifically designed to provide sonodynamic therapy via standing waves providing sonochemical activation of blood-borne drug precursors. This occurs in response to control signals coupled from the implantable electronic circuitry ofFIGS. 1 through 6 bylines 281. Theultrasonic transducer configuration 278 is useful where local drug activation is desired in order to deliver the drug to the vessel having thestent 279 therein. Theultrasonic transducer configuration 278 is also useful when the downstream vasculature or an organ or tumor that is supplied blood via the downstream vasculature is the intended target for the activated drug. - The
stent 279 includes an implantableultrasonic transducer 280 on a first surface and adevice 282 on a second surface. Thedevice 282 may be either another ultrasonic transducer similar to thetransducer 280 or an acoustic reflector. Theultrasonic transducer 280 may be coupled to implantable electronic circuits using any of the approaches described in connection withFIGS. 1 through 6 . In one embodiment, the layer structure described in connection withFIG. 17 is applicable to thetransducer 280. The standing acoustic wave, represented by the dashed parallel lines inFIG. 23 , that is realized between thetransducer 280 and thedevice 282 results in greater peak acoustic field strength for a given input energy level, which increases the rate of sonochemical drug activation and reduces the power levels required for sonochemical drug activation. Peak acoustic pressure increases of three- to five-fold are likely in most clinical settings. - The piezoelectric material forming the
transducer 280 may comprise piezoelectric plastic materials such as PVDF, P(VCN/VAc) or P(VDF-TrFE), available from AMP Sensors of Valley Forge, Pa., or any of the piezoelectric ceramics, e.g., lead zirconium titanate. In one embodiment, PZT-4 material available from Morgan-Matroc of Bedford, Ohio provides high electroacoustic coupling and low acoustic losses. In another embodiment, the piezoelectric plastic P(VDF-TrFE) provides high electroacoustic coupling and low acoustic losses. - The transducer 280 (and, when the
device 282 is a transducer, the device 282) may be of the type described, for example, with respect toFIGS. 13 through 18 , or may be a slab type ultrasonic transducer, or may be similar to that shown and described in connection withFIG. 24 , described below. In this application, the alignment between thetransducer 280 and thedevice 282 must be maintained in order to preserve parallelism of the surface oftransducer 280 that surfaces thedevice 282 and the surface of thedevice 282 that faces thetransducer 280. It is also important to keep these surfaces opposed to each other, i.e., relative lateral motion of thetransducer 280 and thedevice 282 must be inhibited. The result of maintaining this alignment is to form an acoustic cavity analogous to an optical Fabry-Perot resonator. -
FIG. 23 also showsbiocompatible coatings 284 surrounding both thetransducer 280 and thedevice 282. Thebiocompatible coatings 284 are analogous to the biocompatibleouter coating 192 ofFIG. 17 . Thetransducer 280 may also include an acoustic backing analogous to theacoustic backing 194 ofFIG. 17 , disposed on thetransducer 280 as described in conjunction withFIG. 17 . When an acoustic backing is employed with the transducer 280 (or in the device 282), it is important that the surface oftransducer 280 that faces the device 282 (and the surface of thedevice 282 that faces the transducer 280) not be coated with the acoustic backing material. - When the
device 282 is chosen to be an acoustic reflector, either a low impedance reflector (i.e., providing an acoustic reflection coefficient approaching −1) or a high impedance reflector (i.e., providing an acoustic reflection coefficient approaching +1) may be employed. Low-density foams (e.g., analogous to theacoustic backing material 194 ofFIG. 17 ) or aerogels provide low acoustic impedances suitable for use in acoustic reflectors, while rigid bodies such as metals or ceramics provide high acoustic impedances suitable for use in acoustic reflectors. Setting the thickness TR of the acoustic reflector to be an odd multiple of one quarter of an acoustic wavelength, as measured in the acoustic reflector material, increases the reflection coefficient of the acoustic reflector. - Alternatively, methods for localized delivery of medication include encapsulation of medications in delivery vehicles such as microbubbles, microspheres or microballoons, which may be ruptured to locally release the medications via localized energy provided by implanted transducers. In some embodiments, the delivery vehicles may include magnetic material, permitting the delivery vehicles to be localized via an applied magnetic field, as described in U.S. Pat. No. 4,331,654 entitled Magnetically-Localizable, Biodegradable Lipid Microspheres.
- In one embodiment, the
device 282 is formed from a magnetic ceramic or a magnetic metal alloy, and is also capable of acting as an efficient acoustic reflector. This embodiment allows localization of magnetic delivery vehicles via the static magnetic field associated with thedevice 282, followed by insonification of the delivery vehicles when appropriate via ultrasound emitted by thetransducer 280 in response to signals from any of the implantable electronic circuits shown inFIGS. 1 through 6 . As used herein, the term “insonify” means “expose to sound” or “expose to ultrasound”; “insonification” is used to mean exposure to sound or ultrasound. Insonification of delivery vehicles can provide localized heating, can rupture microbubbles to locally release drugs or drug precursors contained in the delivery vehicles or can trigger sonodynamic activation of drug precursors that are blood-borne or that are released when the delivery vehicles rupture. Microbubbles containing antistenotic agents are described, for example, by R. L. Wilensky et al. in Microspheres, Semin. Intervent. Cardiol., 1: 48-50, 1996. Microbubbles of various compositions and filled with various drugs are developed and manufactured by ImaRx Pharmaceutical Corp. of Tucson Ariz. An advantage that is provided by use of an implanted permanent magnet for localization of magnetic delivery vehicles in this embodiment and others is that permanent magnets do not require a rechargeable energy source in order to function. In some embodiments, this can provide a way of reducing power needs from the RF-to-DC power supply 32 ofFIGS. 1 through 6 . - The frequency of the ultrasound from the therapeutic transducer can be varied to enhance or to reduce cavitation resulting from the ultrasound emitted from the transducer. Suppression of cavitation via frequency modulation is described in U.S. Pat. No. 5,694,936 entitled “Ultrasonic Apparatus For Thermotherapy With Variable Frequency For Suppressing Cavitation.” Methods for suppression or enhancement of cavitation are described in U.S. Pat. No. 4,689,986 entitled “Variable Frequency Gas-Bubble-Manipulating Apparatus And Method.” Enhancing cavitation to enhance sonodynamic activation, rupture of microspheres, microballoons or microbubbles, to locally heat tissue or to destroy tissue is possible by causing the frequency of the emitted ultrasound to decrease with time. On the other hand, cavitation may be decreased by causing the frequency of the emitted ultrasound to increase with time. This may be used to limit tissue damage while still supplying sufficient ultrasound to accomplish, e.g., a diagnostic purpose.
- Sonodynamic activation of drugs or sonically-induced delivery vehicles rupture may occur at reduced power levels when properly-phased collinear acoustic signals at two different frequencies are provided. This effect has been shown to be particularly advantageous when one signal is at a frequency that is the second harmonic of the other signal and the two signals have an appropriate phase relationship. Increased tissue damage for a given intensity of ultrasound has also been reported by S. I. Umemura in Effect Of Second-Harmonic Phase On Producing Sonodynamic Tissue Damage, published in the 1996 IEEE Ultrasonics Symposium Proceedings, IEEE cat. no. 0-7803-3615-1/96, pp. 1313-1318. Sonochemical activation of a gallium-deuteroporphyrin complex (ATX-70) at reduced total power density by use of properly phased signals comprising a first signal and a second signal at twice the frequency of the first signal is described by S. I. Umemura et al. in Sonodynamic Approach To Tumor Treatment, published in the 1992 IEEE Ultrasonics Symposium Proceedings, IEEE cat. no. 1051-0117/92/0000-1231, pp. 1231-1240. An example of a transducer that is designed to provide for transduction of two ultrasonic signals, one of which may be the second harmonic of the other, is now described with reference to
FIG. 24 . -
FIG. 24 illustrates an embodiment of a dual frequencyultrasonic transducer 290. Thedual frequency transducer 290 is designed to provide two different frequencies of collinearly propagating ultrasound, where one of the frequencies may be the second harmonic of the fundamental transducer frequency, when supplied with suitable electrical signals. The phases of the two signals may be adjusted by the implantable electronic circuit ofFIGS. 4 through 6 and this may be in response to signals from the power supply andpatient monitoring console 101 ofFIG. 12 . Thedual frequency transducer 290 comprises adisc 292 of piezoelectric material, poled, for example, as indicated bydirection arrow 298. Thedisc 292 has a diameter D and a thickness TX. Electrode 294 andelectrode 296 are formed on opposed surfaces of thedisc 292 as described in conjunction with the rear andfront electrodes FIG. 17 above. - In one embodiment, the diameter D is chosen to provide the desired fundamental transducer frequency via radial mode coupling, while the thickness TX is chosen to provide the second harmonic of the fundamental transducer frequency via thickness mode coupling. In this case, the diameter to thickness ratio D/TX may be approximately 2:1. Conventional mode charts provide more precise ratios for a variety of materials. The radial mode comprises radial particle motion primarily into and out from the center of the disc, i.e., perpendicular to the
direction arrow 298, and symmetric about a cylindrical axis of thedisc 292. The surfaces of thedisc 292 exhibit longitudinal motion (i.e., parallel to the direction arrow 298) in response to the radial mode oscillation because of the Poisson's ratio of the material. The thickness mode comprises particle motion parallel to thedirection arrow 298. As a result, acoustic energy propagating in the same direction at both frequencies may be coupled out of thedisc 292 via the surfaces on which theelectrodes electrode - In another embodiment, the radial mode providing ultrasound at the fundamental transducer frequency may be chosen to be a harmonic of the lowest radial mode of the
transducer 290. Thetransducer 290 may then be designed to have a larger diameter D than is possible when the lowest radial mode corresponds to the fundamental transducer frequency. This allows a larger area to be insonified by both ultrasonic signals than is otherwise feasible. - In one embodiment, frequencies of 500 kHz and 1 MHz are chosen as the two output frequencies for the
dual frequency transducer 290. When thedisc 292 comprises lead zirconium titanate (PZT), the diameter D is about 4 mm and the thickness TX is about 2 mm. The resultingdual frequency transducer 290 is small enough to be incorporated in an implantable device and yet also large enough to insonify a significant portion of the lumen of many blood vessels or stents. - In an alternative embodiment, a rectangular slab may be substituted for the
disc 292. In one embodiment, a lateral mode may then be used instead of the radial mode associated with thedisc 292 to provide the resonance at the fundamental frequency, with the thickness mode providing the resonance at the second harmonic. Conventional mode charts are used to select the ratios of the relevant dimensions. - Coating a cylindrical sidewall of the
disc 292 and one of theelectrodes acoustic backing 194 ofFIG. 17 ) allows the other of theelectrodes acoustic isolator 300 to have a low relative dielectric constant reduces capacitive loading of thedual frequency transducer 290 by the patient's body, which, as noted above, has a high relative dielectric constant (approaching 80) and which also includes conductive solutions. Coating theacoustic isolator 300 with a groundedconductor 302, selecting theelectrode 296 to be a grounded electrode and selecting theelectrode 294 to be a driven electrode reduces unwanted radiation of electromagnetic signals from thetransducer 292. A thin biocompatible coating 304 (analogous to theouter coating 192 ofFIG. 17 ) protects thedual frequency transducer 290 from exposure to biological matter without preventing radiation of ultrasound from the surface bearing theelectrode 296. - Other types of localized therapy include coupling a thermally-activated medication to carrier molecules that have affinity to tumor tissue. Localized heating of the tumor tissue enables selective activation of the medication in the tumor tissue, as described in U.S. Pat. No. 5,490,840 entitled Targeted Thermal Release Of Drug-Polymer Conjugates. Localized heating may be effected through ultrasound via an ultrasonic transducer, e.g., transducers 44-46 (
FIGS. 1 through 6 ) implanted to allow insonification of the affected area. Higher acoustic frequencies provide shorter penetration depths, ie., provide greater control over where the ultrasound and therefore the resultant heat is delivered. Additionally, heating is increased by ultrasonic cavitation in the presence of microbubbles, microspheres or microballoons. Other methods for providing localized magnetic forces or heating include electromagnetic or resistive heating transducers 44-46 comprising coils. -
FIG. 25 illustrates acoil 312 integrated into astent 310. Thecoil 312 comprises saddle-shapedwires 313 integrated into thestent 310. Thecoil 312 may be an electromagnetic transducer used to magnetically capture delivery vehicles bearing drugs.Leads 314 couple thecoil 312 to animplantable control IC 315, which may comprise the implantable electronic circuits of any ofFIGS. 1 through 6 . The implantable electronic circuits ofFIGS. 4 through 6 may provide advantages in this situation because the frequency of the signal providing power to the implantable electronic circuits may be different from the frequency of the signals to the transducers 44-46, such as thecoil 312. This may avoid a situation where the signals providing power to the implantable electronic circuits also result in release of drugs in the vicinity of theRF coupling coil 30 that is receiving the electrical power. - When a suitable current, either AC or DC, is supplied via the
leads 314, a magnetic field represented byflux lines 316 is generated. The magnetic field captures magnetic delivery vehicles that have been introduced into the patient's bloodstream. The increased concentration of delivery vehicles in the target vicinity can be used to provide local increases in delivery of drugs contained in the delivery vehicles. - Microbubbles including medication may be localized via a magnetic field and ruptured via an oscillating magnetic field as described in U.S. Pat. No. 4,652,257 entitled Magnetically-Localizable, Polymerized Lipid Vesicles And Method Of Disrupting Same. Suitable magnetic fields may be provided via application of RF or RF and DC electrical energy to the
coil 312. In these embodiments, one or more of the transducers 44-46 ofFIGS. 1 through 6 comprise thecoil structure 312. In response to signals coupled to the implantable electronic circuit, the transducer 44-46 that is selected is activated and is supplied with current to either trap the magnetic delivery vehicles so that they can be ruptured via signals provided from another selected transducer 44-46 (e.g., an ultrasonic transducer that ruptures microbubbles, microspheres or microballoons via cavitation), or an oscillating magnetic field may be superposed on the magnetic fields generated by thecoil 312 used to trap the delivery vehicles. - Referring again to
FIG. 25 , in another embodiment, apermanent magnet 311 may be included on or in thestent 310 to provide a static magnetic field for localization of magnetic delivery vehicles. An oscillating magnetic field may then be provided via signals supplied to thecoil 312 to rupture the delivery vehicles under the control of the implantable electronic circuit of any ofFIGS. 1 through 6 , where thecoil 312 acts as one of the transducers 44-46. These embodiments may reduce power requirements for theimplantable control IC 315 while retaining external control over when the drug or drug precursor is released via signals from the power supply andpatient monitoring console 101 of FIG. 12. Other types of coils, e.g., analogous to the RF coupling coils 30B, 30C or 30D ofFIGS. 7 through 10 , or 121 ofFIGS. 11A and 11B , may also be used instead of theRF coupling coil 312. -
FIG. 26 illustrates another embodiment of acoil 312A integrated into astent 310A. Thecoil 312A is analogous to thecoil 312 ofFIG. 25 , but is shaped as a cylindrical coil rather than as a saddle-shaped spiral. Leads314 A couple wires 313A comprising thecoil 312A to an implantable control IC 315A, which is analogous to theimplantable control IC 315 ofFIG. 25 . When a suitable current, either AC or DC, is supplied via theleads 314A, a magnetic field represented byflux lines 316A is generated. Thecoil 312A may be used to capture magnetic delivery vehicles that have been introduced into the patient's bloodstream. - In other embodiments, the
coils coils coils stent 310A may form a resistive heating transducer that is heated via magnetically-induced currents. - Stents are typically fashioned from metals that are biocompatible, such as titanium alloys (e.g., Nitinol, a nickel titanium alloy), stainless steel (e.g., 316L), platinum/iridium alloys or tantalum. All of these materials are suitable for fashioning a stent that is to be directly heated by RF-induced eddy currents (such stents would not include slots such as
slot 118,FIG. 11A , or insulating couplings such as 119,FIG. 11A , or 146,FIG. 11B ), however, titanium and Nitinol have the highest electrical resistivity, while platinum/iridium and tantalum have the lowest electrical resistivity. When a stent body is to be directly heated by induced eddy currents, titanium or Nitinol may present advantages. - When a RF coupling coil is to be fashioned from these materials, those applications with higher power requirements may favor the materials with the lower resistivities.
- When a current is passed through coils analogous to RF coupling coils 312 or 312A but comprising resistive material, or through a stent body as eddy currents, a local temperature rise is produced. This local temperature rise may be employed to rupture microbubbles having a melting point slightly above normal human body temperatures. One system using microbubbles having a controlled melting point to facilitate rupture of the microbubbles at predetermined localized areas within a patient's body is described, for example, in U.S. Pat. No. 4,558,690 entitled Method Of Administration Of Chemotherapy To Tumors. The localized heating may be provided by a structure similar to the cylindrical
RF coupling coil 30A ofFIG. 7 , the woven mesh coils 30B and 30C ofFIGS. 8 and 9 , the saddleRF coupling coil 30D ofFIG. 10 , theRF coupling coil 121 ofFIGS. 11A and 11B , thecoil 312 ofFIG. 25 or thecoil 312A ofFIG. 26 , with the conductors of the coils comprising a suitably resistive material such as nichrome wire. The heating may be supplied directly by RF excitation of thecoils 30A through 30D or 121, or it may be effected via the implantable electronic circuits ofFIGS. 1 through 6 . This may be in response to signals from the power supply andpatient monitoring console 101 ofFIG. 12 . Additionally, delivery vehicles such as microbubbles, microspheres or microballoons can increase localized heating of tissue via rupture of the delivery vehicles caused by localized application of ultrasound, as discussed, for example, in Technical Report: Drug And Gene Delivery, Jul. 2, 1997, ImaRx Pharmaceutical Corp. - Transducers may be employed to facilitate drug penetration through the wall of a stent or stent graft and into the surrounding vasculature via sonophoresis, i.e., ultrasound enhancement of drug penetration into body tissues, or via iontophoresis, i.e., electrical field enhancement of drug penetration into body tissues, when suitable transducers are included in the stent or stent graft.
- Methods and apparatus for localized drug delivery via sonophoresis or phonophoresis are described in U.S. Pat. No. 4,484,569 entitled Ultrasonic Diagnostic And Therapeutic Transducer Assembly And Method For Using, U.S. Pat. No. 5,016,615 entitled Local Application Of Medication With Ultrasound and U.S. Pat. No. 5,267,985 entitled Drug Delivery By Multiple Frequency Phonophoresis. These patents generally discuss transdermal delivery of medication to an affected area and note that use of more than one frequency of ultrasonic energy is beneficial in some situations.
- An iontophoretic catheter for drug delivery is described in Iontophoretic Drug Delivery System, by R. G. Welsh et al., Semin. Intervent. Cardiol., No. 1, pp. 40-42 (1996). The system uses a microporous membrane enclosing a drug solution and a drug delivery electrode. A reference electrode is coupled to the biological tissue at a site that is separate from the drug delivery electrode. The reference and drug delivery electrodes are coupled to a power supply that provides an electrical potential between the two electrodes. Cationic drugs move from the anode towards the cathode, while anionic drugs move from the cathode towards the anode, with the rate being generally proportional to the current. Control over localized drug delivery is effected via control of the current and the duration of the current from the drug delivery electrode. One application is for delivery of antirestenotic agents.
- Other uses of iontophoresis are described in U.S. Pat. No. 4,383,529 entitled lontophoretic Electrode Device, Method and Gel Insert and U.S. Pat. No. 4,416,274 entitled Ion Mobility Limiting lontophoretic Bioelectrode. These generally describe iontophoretic apparatus for localized transdermal drug delivery. Catheters adapted to provide localized iontophoretic drug delivery are described in U.S. Pat. No. 4,411,648 entitled lontophoretic Catheter Device, and U.S. Pat. No. 5,499,971 entitled Method for Iontophoretically Delivering Drug Adjacent To A Heart. These discuss specific problems that are most readily addressed via localized drug delivery, including treatment of vascular regions to reduce restenosis following PTCA, drug delivery to tumor sites and techniques for iontophoretically delivering drugs in the vicinity of the heart without inducing arrhythmia due to electrical stimulation of heart muscles and nerves. In one embodiment, this is effected together with provision of electrical fields effective in providing drug transport by chopping a DC potential difference at a rate of between 5 and 15 kHz or by providing an asymmetric AC waveform that is in this frequency range. These techniques are necessary because the current being used for iontophoresis travels through a significant and somewhat unpredictable amount of body tissue that may well include muscles and nerves associated with the heart.
- These concepts become more powerful when combined with the implantable transducers 44-46 of
FIGS. 4 through 6 for providing the energy to locally deliver or locally activate the medications. An example of an iontophoretic transducer is described in conjunction withFIG. 27 below. -
FIG. 27 illustrates an embodiment of aniontophoretic system 320 for local drug delivery in the vicinity of an implantedstent 322. Theiontophoretic system 320 includes animplantable control IC 324, which may be coupled to thestent 322. Theimplantable control IC 324 is coupled viawires 326 to afirst electrode 328 and to asecond electrode 330. The first 328 and second 330 electrodes are insulated from thestent 322 when thestent 322 comprises conductive material, unless thestent 322 comprises one of theelectrodes stent 322, or may be disposed such that one is inside thestent 322 and the other is external to thestent 322. - A potential difference is established between the first 328 and second 330 electrodes by the
implantable control IC 324 in response to signals coupled from outside the patient's body, via a RF coupling coil (not illustrated) as discussed above. The potential difference causes some types of drugs to migrate from one of theelectrodes stent 322 is implanted. For example, systemically-administered drugs may be selectively transported from the blood into the vasculature surrounding astent 322 to provide increased local concentrations of antistenotic agents. - One advantage of this technique is that the currents produced by the
iontophoretic system 320 are extremely localized, i.e., are substantially confined to the area between theelectrodes iontophoretic system 320 may employ a DC voltage to effect iontophoretic drug delivery to parts of the body that cannot safely be treated via a catheterized system using DC for iontophoretic drug delivery. This is advantageous in improving the efficiency of drug delivery and in reducing exposure of other portions of the body to the electrical currents being employed for iontophoresis. One area where this may provide advantages, depending on stent placement and other factors, is in treating restenosis of cardiac blood vessels following stent insertion as a part of a PTCA treatment. Astent 322 intended for this purpose may also include sensors providing signals indicative of blood flow through the stent and therefore capable of providing data indicative of blockage as it develops. Additionally, thestent 322 includingiontophoretic electrodes stent 322 or that are included in the vasculature upstream of thestent 322. - Another method for localized drug activation uses light supplied by an optical transducer, where the light is of the appropriate wavelength and intensity to break precursor molecules down into drugs. U.S. Pat. No. 5,445,608 entitled Method And Apparatus For Providing Light-Activated Therapy, describes a photodynamic therapy achieved by photoactivation of suitable optically active drugs. As described in this patent, the drugs are activated via catheterized light emitters inserted at the site to be treated and providing light at the wavelength required in order to activate the drugs and at the location where the activated drugs are needed for therapeutic purposes. Examples of precursor substances that can be optically activated by being broken down into drug molecules include long-chain cyanine dyes, dimers of phthalocyanine dyes and porphyrin compounds. A wide selection of solid state light sources including laser diodes and light emitting diodes is commercially available from a variety of vendors, including Motorola of Phoenix, Ariz. Laser diodes or light emitting diodes may be employed as transducers 44-46 in any of the systems shown in
FIGS. 1 through 6 to provide light for photoactivation of drugs within a patient's body via signals from the implantable electronic circuit in response to signals transmitted from the power supply andpatient monitoring console 101 ofFIG. 12 . -
FIG. 28 illustrates an embodiment wherein light emitting oroptical transducers 338 are coupled to astent 336. Thelight emitting transducers 338 may comprise light emitting diodes having an appropriate wavelength or may comprise diode lasers. Thelight emitting transducers 338 may be coupled in series vialines 340, as shown inFIG. 28 , or may be coupled in parallel. When thelight emitting transducers 338 are coupled in series, one disadvantage is that catastrophic failure of one of thelight emitting transducers 338 that causes the failedlight emitting transducer 338 to fail to pass enough current for light emission may also prevent the remainder of thelight emitting transducers 338 from operating. - The
light emitting transducers 338 are coupled vialines 342 to animplantable control IC 344, which is in turn coupled to a RF coupling coil (not illustrated inFIG. 28 ) that provides energy and control signals. Thelight emitting transducers 338 may be disposed on the outside of thestent 336, as shown, or on the inside of thestent 336 or both as required for a given application. - The transducers 44-46 of
FIGS. 1 through 6 may concentrate or activate medications by supplying heat, via resistive processes or insonification, or may employ light, magnetic fields or electrical fields for localized drug delivery or activation. Theultrasonic transducer 290 ofFIG. 24 is, among other ultrasonic transducers, also suited to increasing drug penetration of drugs via sonophoresis into, e.g., tumors or vascular walls via an implantable electronic circuit such as any of those shown inFIGS. 4 through 6 . - An example of an application for the systems described above occurs in the situation where a stent is implanted to correct a stenosis or to repair an aneurysm in a blood vessel. Over time, tissue ingrowth at the ends of the stent can lead to stenosis, which can lead to thrombus formation. Thrombosis threatens the viability of the stent, and may require aggressive intervention using surgery or drugs. It is very undesirable to have to surgically resolve this situation if there is a viable alternative approach for relieving the blockage. One approach is to infuse the patient with thrombolytic drugs. This may lead to hemorrhagic consequences in other parts of the body, especially if the patient has, for example, recently had surgery. One approach to reducing the amount of thrombolytic drugs required to resolve thromboses in vitro is described in Prototype Therapeutic Ultrasound Emitting Catheter For Accelerating Thrombolysis, J. Ultrasound Med. 16, pp. 529-535 (1997). In this study, urokinase alone as a fibrinolytic agent was compared to urokinase in the presence of ultrasonic energy, with the latter showing marked improvement in the degree of fibrinolysis of artificial blood clots in glass tubes.
- When, however, the stent includes a transducer, such as an ultrasonic transducer, coupled to the implantable electronic circuit of any of
FIGS. 1 through 6 , the introduction of a thrombolytic drug into the bloodstream of the patient can be followed by generation of ultrasound within the stent via the transducer and under the control of an attending physician. This allows the thrombolytic drug, e.g., urokinase, streptokinase or tissue plasminogen activator, to be activated at the site of the thrombus and under the control of the attending physician, reducing the probability of hemorrhagic consequences at portions of the patient's body remote from the site being treated. It also enables rapid onset of treatment, which can be critical in some situations, e.g., in the event of heart attack or stroke induced via thrombolysis, and may obviate invasive surgery in the event that the therapeutic transducer has already been implanted in a prior procedure. - Additionally, when flow or pressure sensors such as are described with respect to
FIGS. 13 through 16 or 18 are also included with the stent when the stent is implanted and these are also coupled to the implantable electronic circuits of any ofFIGS. 2 through 6 , the attending physician may be able to obtain information that is indicative of graft condition. This can allow the physician to more readily determine if the condition is treatable without resorting to invasive evaluation and intervention. Monitoring during non-invasive treatment, e.g., local drug activation, accomplished through use of an implanted blood velocity or blood pressure transducer, may allow assessment of the progress of thrombolysis that may, in turn, permit successful noninvasive treatment without incurring undue risk to the patient. - Further, when stents are implanted to relieve stenosis, restenosis due to tissue ingrowth tends to occur within the first 6 months following angioplasty, with the greatest loss of luminal diameter occurring between the first and third month. Detection of tissue growth can be determined via pressure sensors as described above or via incorporation of the
dielectric sensing filaments 234 and theimplantable IC sensor 220B ofFIGS. 21A and 21B . When the ultrasonic transducers, such as those of any ofFIGS. 13-18 , 23 or 24, are included in the upstream side of an implanted stent, precursor drugs activated sonodynamically may locally provide antistenotic agents such as colchicine, heparin, methotrexate, angiopeptin or hirudin to relieve or reduce restenosis without requiring systemic administration of the drugs. Alternatively, delivery vehicles ruptured via ultrasound may provide localized delivery of antistenotic agents. This provides a way of controlling restenosis on an as-needed basis as determined via the benefit of diagnostic data, under the control of a physician, and without requiring anesthesia or surgery. An advantage associated with at least some of the therapeutic transducers described herein is that they are not necessarily specific to one drug or condition. For example, ultrasonically activated therapy provides advantages in treatment of both restenosis and thromboses, either of which may threaten viability of an implanted stent. - From the foregoing it will be appreciated that, although specific embodiments of the invention have been described herein for purposes of illustration, various modifications may be made without deviating from the spirit and scope of the invention. Accordingly, the invention is to be understood broadly and is not limited except as by the appended claims.
Claims (63)
1. An apparatus comprising:
an endoluminal implant; and
a transducer coupled to said endoluminal implant.
2. The apparatus of claim 1 wherein said transducer comprises a therapeutic transducer.
3. The apparatus of claim 1 wherein said transducer comprises a therapeutic transducer chosen from a group comprising an electromagnetic transducer, an optical transducer, an ultrasonic transducer, a resistive heater transducer and an iontophoretic transducer.
4. The apparatus of claim 1 , further comprising a RF coupling coil having an output coupled to said transducer.
5. The apparatus of claim 4 , further comprising a RF-to-DC power supply electrically coupled to said output of said RF coupling coil and having an output coupled to a signal source that is in turn coupled to said transducer, said signal source activating said transducer in response to signals from said RF coupling coil.
6. The apparatus of claim 1 wherein said endoluminal implant is chosen from a group comprising: a stent and a stent graft.
7. The apparatus of claim 2 wherein said therapeutic transducer is coupled to a saddle-shaped coil integrated into a wall of said endoluminal implant.
8. The apparatus of claim 2 wherein said therapeutic transducer is coupled to a helical coil integrated into a wall of said endoluminal implant.
9. The apparatus of claim 4 wherein:
said endoluminal implant comprises a stent; and
said RF coupling coil comprises a woven mesh of wire integrated into a wall of said stent.
10. The apparatus of claim 9 wherein said woven mesh of wire comprises:
a first set of coils of insulated wire each forming a right-handed spiral; and
a second set of coils of insulated wire each forming a left-handed spiral, said second set of coils interwoven with said first set of coils, wherein said first set of coils and said second set of coils are electrically coupled in series in a daisy-chain configuration.
11. The apparatus of claim 9 wherein said woven mesh of wire comprises:
a first set of coils of insulated wire each forming a right-handed spiral, each of said coils of said first set of coils having a first end and a second end, wherein said first ends are electrically coupled to each other and said second ends are coupled to each other; and
a second set of coils of insulated wire each forming a left-handed spiral, said first and second sets of coils interwoven with each other to form said woven mesh, each of said coils of said second set of coils having a first end and a second end, wherein said first ends of said second set of coils are electrically coupled to each other and said second ends of said second set of coils are coupled to each other, said first and second sets of coils being electrically coupled to each other and to said transducer.
12. The apparatus of claim 2 wherein said therapeutic transducer includes a regular solid comprising piezoelectric material, wherein a first resonance frequency is determined by a first dimension of said regular solid and a second resonance frequency is determined by a second dimension of said regular solid, said regular solid including a first electrode coupled to a first surface of said regular solid and a second electrode coupled to a second surface of said regular solid.
13. The apparatus of claim 12 , further comprising an acoustic isolator disposed on said first electrode and on a sidewall of said regular solid and wherein said first dimension is approximately twice said second dimension.
14. The apparatus of claim 2 wherein said therapeutic transducer comprises:
an ultrasonic transducer having an acoustic radiating surface, wherein a first electrode and a second electrode are coupled to said ultrasonic transducer, said ultrasonic transducer coupled to a first wall of said endoluminal implant; and
an acoustic reflector coupled to a second wall of said endoluminal implant, said acoustic reflector being maintained in alignment with and facing said acoustic radiating surface of said ultrasonic transducer by said endoluminal implant.
15. The apparatus of claim 14 wherein said acoustic reflector comprises a magnet.
16. The apparatus of claim 2 wherein said therapeutic transducer comprises:
a first ultrasonic transducer having an acoustic radiating surface, wherein a first electrode and a second electrode are coupled to said first ultrasonic transducer, said first ultrasonic transducer coupled to a first wall of said endoluminal implant; and
a second ultrasonic transducer having an acoustic radiating surface, wherein a first electrode and a second electrode are coupled to said second ultrasonic transducer, said second ultrasonic transducer being coupled to a second wall of said endoluminal implant such that said acoustic radiating surface of said first ultrasonic transducer is aligned with and facing said acoustic radiating surface of said second ultrasonic transducer.
17. The apparatus of claim 2 , further comprising:
a RF coupling coil integrated into a wall of said endoluminal implant;
an implantable electronic circuit, said implantable electronic circuit including a RF-to-DC power supply circuit coupled to said RF coupling coil, whereby RF energy coupled into said RF coupling coil may be converted to DC power, and whereby RF coded information may be exchanged between said RF coupling coil and said implantable electronic circuit; and
18. The apparatus of claim 17 , wherein said implantable electronic circuit also includes:
RF decoding circuitry and a multiplexer, said RF decoding circuitry coupled to said RF coupling coil, whereby said multiplexer may supply signals from said implantable electronic circuit to said therapeutic transducer; and
a second transducer coupled to said endoluminal implant wherein said first and second transducers are coupled to said implantable electronic circuit and comprise ultrasonic transducers configured to provide first and second acoustic waves in a space between said first and second transducers in response to signals from said implantable electronic circuit.
19. The apparatus of claim 2 , further comprising a diagnostic transducer coupled to said endoluminal implant
20. The apparatus of claim 19 , wherein said diagnostic transducer provides signals indicative of a parameter describing a fluid flowing through said endoluminal implant, wherein said parameter is chosen from a list comprising: fluid flow, pressure, temperature and biochemical properties.
21. The apparatus of claim 4 wherein said therapeutic transducer includes a therapeutic transducer chosen from a group comprising: ultrasonic transducer, optical transducer, magnetic transducer, resistive heating transducers and iontophoretic transducers.
22. An apparatus comprising:
an endoluminal implant;
a RF coupling coil coupled to said endoluminal implant;
an implantable electronic circuit electrically coupled to said RF coupling coil and physically coupled to said endoluminal implant, said RF coupling coil for supplying electrical power to said implantable electronic circuit and for coupling control and data signals to and from said implantable electronic circuit; and
a therapeutic transducer electrically coupled to said implantable electronic circuit, said therapeutic transducer for delivering therapeutic energy to a lumen disposed within said endoluminal implant in response to said control signals.
23. The apparatus of claim 22 wherein said RF coupling coil is disposed on said endoluminal implant and comprises a RF coupling coil chosen from a group comprising: a saddle-shaped coil, a helical coil and a woven mesh coil.
24. The apparatus of claim 22 further comprising a diagnostic transducer coupled to said endoluminal implant, said diagnostic transducer electrically coupled to said implantable electronic circuit to provide diagnostic signals thereto.
25. The apparatus of claim 24 wherein said diagnostic transducer comprises a pressure transducer arranged to measure a pressure of a fluid in a lumen of said endoluminal implant.
26. The apparatus of claim 22 wherein said therapeutic transducer comprises means for insonifying a lumen disposed in said endoluminal implant.
27. The apparatus of claim 22 wherein said therapeutic transducer comprises means for insonifying a lumen disposed in said endoluminal implant with one or more acoustic waves.
28. The apparatus of claim 22 , further comprising a diagnostic transducer coupled to said endoluminal implant, said diagnostic transducer including an electrical coupling to said implantable electronic circuit for exchanging data between said diagnostic transducer and said implantable electronic circuit.
29. The apparatus of claim 28 wherein said diagnostic transducer comprises a conformal transducer array coupled to said endoluminal implant to measure fluid velocity through a lumen extending through said endoluminal implant.
30. The apparatus of claim 28 wherein said diagnostic transducer comprises a first electrode and a second electrode, said first and second electrodes disposed in a fixed, spaced-apart relationship within a lumen of said endoluminal implant and adjacent a wall thereof, whereby capacitance or resistance measurements between said first and second electrodes characterize those bodily elements immediately surrounding said first and second electrodes.
31. The apparatus of claim 28 wherein said diagnostic transducer comprises a first pressure transducer disposed at an inlet whereby fluid enters said endoluminal implant.
32. The apparatus of claim 31 wherein said diagnostic transducer further comprises a second pressure transducer disposed at an outlet whereby fluid exits said endoluminal implant.
33. The apparatus of claim 22 wherein said therapeutic transducer includes one or more light sources.
34. The apparatus of claim 22 wherein said therapeutic transducer comprises an iontophoretic transducer.
35. The apparatus of claim 22 wherein said therapeutic transducer comprises an electromagnetic transducer.
36. The apparatus of claim 22 wherein said therapeutic transducer comprises a resistive heating transducer.
37. The apparatus of claim 22 wherein said therapeutic transducer comprises:
a first ultrasonic transducer having an acoustic radiating surface, a first electrode and a second electrode each coupled to said first ultrasonic transducer, said first ultrasonic transducer coupled to a first wall of said endoluminal implant; and
a second ultrasonic transducer having an acoustic radiating surface, a first electrode and a second electrode each coupled to said second ultrasonic transducer, said second ultrasonic transducer being coupled to a second wall of said endoluminal implant such that said acoustic radiating surface of said first ultrasonic transducer is aligned with and facing said acoustic radiating surface of said second ultrasonic transducer.
38. The apparatus of claim 22 wherein said therapeutic transducer comprises:
an ultrasonic transducer having an acoustic radiating surface, a first electrode and a second electrode each coupled to said ultrasonic transducer, said ultrasonic transducer coupled to a first wall of said endoluminal implant; and
an acoustic reflector coupled to a second wall of said endoluminal implant, said acoustic reflector being maintained in alignment with and facing said acoustic radiating surface of said ultrasonic transducer.
39. The apparatus of claim 38 wherein said acoustic reflector comprises a magnet.
40. The apparatus of claim 22 wherein said therapeutic transducer comprises an ultrasonic transducer capable of providing collinear acoustic waves at a first frequency and a second frequency.
41. An apparatus comprising:
an endoluminal implant; and
a RF coupling coil integrated in a wall of said endoluminal implant.
42. An apparatus as claimed in claim 41 , wherein said RF coupling coil comprises a RF coupling coil chosen from a group comprising: a saddle coil, a helical coil and a woven mesh coil.
43. An apparatus as claimed in claim 41 , further comprising a therapeutic transducer electrically coupled to said RF coupling coil.
44. An apparatus as claimed in claim 41 , further comprising:
an implantable electronic circuit coupled to said RF coupling coil, said implantable electronic circuit exchanging data, power and control signals with said RF coupling coil; and
a therapeutic transducer electrically coupled to said implantable electronic circuit and mechanically coupled to said endoluminal implant, said therapeutic transducer supplying energy to a lumen of said endoluminal implant in response to signals from said implantable electronic circuit.
45. The apparatus of claim 44 , further comprising an implantable IC sensor physically coupled to said endoluminal implant and electrically coupled to said implantable electronic circuit.
46. The apparatus of claim 45 , wherein said implantable IC sensor provides electrical signals to said implantable electronic circuit that are indicative of a diagnostic parameter associated with a fluid flowing through said lumen, wherein said diagnostic parameter is chosen from a group comprising: fluid flow, pressure, temperature and biochemical information.
47. A method comprising:
coupling, via a magnetic signal, a signal to a therapeutic transducer contained in an endoluminal implant; and
activating said therapeutic transducer in response to said magnetic signal.
48. The method of claim 47 wherein activating said therapeutic transducer includes ultrasonically activating a drug.
49. The method of claim 47 wherein activating said therapeutic transducer includes rupturing delivery vehicles to locally deliver a drug.
50. The method of claim 47 , further including:
coupling a diagnostic signal from a diagnostic transducer contained in said endoluminal implant to an implantable electronic circuit that is coupled to said endoluminal implant;
transmitting said diagnostic signal from a RF coupling coil that is electronically coupled to said implantable electronic circuit; and
receiving said diagnostic signal at a location outside of a patient's body within which said endoluminal implant is implanted.
51. The method of claim 50 wherein activating said therapeutic transducer includes activating said therapeutic transducer in response to said diagnostic signal.
52. The method of claim 47 wherein activating said therapeutic transducer includes activating an ultrasonic transducer to insonify a lumen of said endoluminal implant with a first ultrasonic signal having a first frequency and a second ultrasonic signal having a second frequency.
53. The method of claim 47 wherein activating said therapeutic transducer includes activating an ultrasonic transducer to insonify a lumen of said endoluminal implant with a first ultrasonic signal having a frequency and a second ultrasonic signal having a second frequency, wherein said first and second ultrasonic signals are collinear.
54. The method of claim 47 wherein activating said therapeutic transducer includes activating a light source.
55. The method of claim 47 wherein activating said therapeutic transducer includes activating an iontophoretic transducer.
56. The method of claim 47 wherein activating said therapeutic transducer includes activating an electromagnetic transducer.
57. A method comprising:
receiving, at a location outside a patient's body, a diagnostic signal from a diagnostic transducer coupled to an endoluminal implant disposed within a patient's body;
transmitting, from said location outside said patient's body, a therapeutic signal in response to receiving said diagnostic signal; and activating a therapeutic transducer that is coupled to said endoluminal implant in response to said therapeutic signal.
58. The method of claim 57 wherein receiving a diagnostic signal includes receiving a diagnostic signal describing fluid flow through a lumen of said endoluminal implant.
59. The method of claim 58 wherein activating a therapeutic transducer includes providing, within said lumen, energy for activating a drug precursor.
60. The method of claim 57 , further comprising:
transmitting, from said location outside said patient's body, a power signal for providing electrical power to implantable electronic circuitry coupled to said endoluminal implant; and
receiving said power signal by a RF coupling coil disposed within said patient's body and electrically coupled to said implantable electronic circuitry.
61. The method of claim 57 , further comprising transmitting, from said location outside said patient's body, a power signal via a hardwired connection extending from said location outside said patient's body to said implantable electronic circuitry, said power signal for providing electrical power to implantable electronic circuitry coupled to said endoluminal implant.
62. The method of claim 60 wherein:
receiving a diagnostic signal includes receiving a diagnostic signal at a first frequency;
transmitting a therapeutic signal includes transmitting a therapeutic signal at said first frequency; and
receiving a power signal includes receiving a power signal at a second frequency different than said first frequency.
63. The method of claim 57 wherein receiving a diagnostic signal includes:
receiving a first diagnostic signal describing fluid pressure at a first end of a lumen of said endoluminal implant; and
receiving a second diagnostic signal describing fluid pressure at a second end of said lumen of said endoluminal implant.
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US11/551,673 US20070112344A1 (en) | 1997-10-14 | 2006-10-20 | Endoluminal implant with therapeutic and diagnostic capability |
US12/204,470 US20090005859A1 (en) | 1997-10-14 | 2008-09-04 | Endoluminal implant with therapeutic and diagnostic capability |
Applications Claiming Priority (5)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US08/949,413 US5807258A (en) | 1997-10-14 | 1997-10-14 | Ultrasonic sensors for monitoring the condition of a vascular graft |
US08/978,038 US5967986A (en) | 1997-11-25 | 1997-11-25 | Endoluminal implant with fluid flow sensing capability |
US09/028,154 US6231516B1 (en) | 1997-10-14 | 1998-02-23 | Endoluminal implant with therapeutic and diagnostic capability |
US09/695,748 US7427265B1 (en) | 1998-02-23 | 2000-10-24 | Endoluminal implant with therapeutic and diagnostic capability |
US11/551,673 US20070112344A1 (en) | 1997-10-14 | 2006-10-20 | Endoluminal implant with therapeutic and diagnostic capability |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US09/695,748 Division US7427265B1 (en) | 1997-10-14 | 2000-10-24 | Endoluminal implant with therapeutic and diagnostic capability |
Related Child Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US12/204,470 Continuation US20090005859A1 (en) | 1997-10-14 | 2008-09-04 | Endoluminal implant with therapeutic and diagnostic capability |
Publications (1)
Publication Number | Publication Date |
---|---|
US20070112344A1 true US20070112344A1 (en) | 2007-05-17 |
Family
ID=21841871
Family Applications (4)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US09/028,154 Expired - Lifetime US6231516B1 (en) | 1997-10-14 | 1998-02-23 | Endoluminal implant with therapeutic and diagnostic capability |
US09/695,748 Expired - Fee Related US7427265B1 (en) | 1997-10-14 | 2000-10-24 | Endoluminal implant with therapeutic and diagnostic capability |
US11/551,673 Abandoned US20070112344A1 (en) | 1997-10-14 | 2006-10-20 | Endoluminal implant with therapeutic and diagnostic capability |
US12/204,470 Abandoned US20090005859A1 (en) | 1997-10-14 | 2008-09-04 | Endoluminal implant with therapeutic and diagnostic capability |
Family Applications Before (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US09/028,154 Expired - Lifetime US6231516B1 (en) | 1997-10-14 | 1998-02-23 | Endoluminal implant with therapeutic and diagnostic capability |
US09/695,748 Expired - Fee Related US7427265B1 (en) | 1997-10-14 | 2000-10-24 | Endoluminal implant with therapeutic and diagnostic capability |
Family Applications After (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US12/204,470 Abandoned US20090005859A1 (en) | 1997-10-14 | 2008-09-04 | Endoluminal implant with therapeutic and diagnostic capability |
Country Status (4)
Country | Link |
---|---|
US (4) | US6231516B1 (en) |
EP (1) | EP1056514A4 (en) |
AU (1) | AU2655599A (en) |
WO (1) | WO1999042176A1 (en) |
Cited By (44)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20060122683A1 (en) * | 2004-12-07 | 2006-06-08 | Scimed Life Systems, Inc. | Medical device that signals lumen loss |
US20070036771A1 (en) * | 2005-08-12 | 2007-02-15 | Cardiac Pacemakers, Inc. | Biologic device for regulation of gene expression and method therefor |
US20080058905A1 (en) * | 2006-09-01 | 2008-03-06 | Wagner Darrell O | Method and apparatus utilizing light as therapy for fungal infection |
US20080058881A1 (en) * | 2006-09-01 | 2008-03-06 | Cardiac Pacemakers, Inc | Method and system for treating post-mi patients |
US20080076836A1 (en) * | 2006-09-01 | 2008-03-27 | Cardiac Pacemakers, Inc | Method and apparatus for using light to enhance cell growth and survival |
US20080281305A1 (en) * | 2007-05-10 | 2008-11-13 | Cardiac Pacemakers, Inc. | Method and apparatus for relieving angina symptoms using light |
US20080307668A1 (en) * | 2007-06-15 | 2008-12-18 | Sidney Watterodt | Methods and devices for drying coated stents |
US20090124881A1 (en) * | 2007-11-12 | 2009-05-14 | Polar Electro Oy | Electrode Structure |
WO2009131612A1 (en) * | 2008-03-21 | 2009-10-29 | William Joseph Drasler | Expandable introducer sheath |
US20090276035A1 (en) * | 2003-08-11 | 2009-11-05 | Igor Waysbeyn | Anastomosis method |
US20100063575A1 (en) * | 2007-03-05 | 2010-03-11 | Alon Shalev | Multi-component expandable supportive bifurcated endoluminal grafts and methods for using same |
US20100070019A1 (en) * | 2006-10-29 | 2010-03-18 | Aneuwrap Ltd. | extra-vascular wrapping for treating aneurysmatic aorta and methods thereof |
US20100070007A1 (en) * | 2008-09-17 | 2010-03-18 | National Ict Australia Limited | Knitted electrode assembly and integrated connector for an active implantable medical device |
US20100171394A1 (en) * | 2008-07-06 | 2010-07-08 | Glenn Richard A | Energy harvesting for implanted medical devices |
US20110160582A1 (en) * | 2008-04-29 | 2011-06-30 | Yongping Zheng | Wireless ultrasonic scanning system |
WO2011095979A1 (en) * | 2010-02-08 | 2011-08-11 | Endospan Ltd. | Thermal energy application for prevention and management of endoleaks in stent-grafts |
US8003157B2 (en) | 2007-06-15 | 2011-08-23 | Abbott Cardiovascular Systems Inc. | System and method for coating a stent |
US20110301668A1 (en) * | 2008-11-21 | 2011-12-08 | Milux Holding Sa | System, method and apparatus for supplying energy to an implantable medical device |
US20130150695A1 (en) * | 2011-12-08 | 2013-06-13 | Biotronik Se & Co. Kg | Medical Implant and Medical Arrangement |
US8486131B2 (en) | 2007-12-15 | 2013-07-16 | Endospan Ltd. | Extra-vascular wrapping for treating aneurysmatic aorta in conjunction with endovascular stent-graft and methods thereof |
US8574287B2 (en) | 2011-06-14 | 2013-11-05 | Endospan Ltd. | Stents incorporating a plurality of strain-distribution locations |
US20140187960A1 (en) * | 2012-12-28 | 2014-07-03 | Volcano Corporation | Intravascular Ultrasound Imaging Apparatus, Interface, Architecture, and Method of Manufacturing |
US8870938B2 (en) | 2009-06-23 | 2014-10-28 | Endospan Ltd. | Vascular prostheses for treating aneurysms |
US8945203B2 (en) | 2009-11-30 | 2015-02-03 | Endospan Ltd. | Multi-component stent-graft system for implantation in a blood vessel with multiple branches |
US8951298B2 (en) | 2011-06-21 | 2015-02-10 | Endospan Ltd. | Endovascular system with circumferentially-overlapping stent-grafts |
US8956397B2 (en) | 2009-12-31 | 2015-02-17 | Endospan Ltd. | Endovascular flow direction indicator |
US8979892B2 (en) | 2009-07-09 | 2015-03-17 | Endospan Ltd. | Apparatus for closure of a lumen and methods of using the same |
US9101457B2 (en) | 2009-12-08 | 2015-08-11 | Endospan Ltd. | Endovascular stent-graft system with fenestrated and crossing stent-grafts |
US9254209B2 (en) | 2011-07-07 | 2016-02-09 | Endospan Ltd. | Stent fixation with reduced plastic deformation |
US9427339B2 (en) | 2011-10-30 | 2016-08-30 | Endospan Ltd. | Triple-collar stent-graft |
US9486341B2 (en) | 2011-03-02 | 2016-11-08 | Endospan Ltd. | Reduced-strain extra-vascular ring for treating aortic aneurysm |
US9526638B2 (en) | 2011-02-03 | 2016-12-27 | Endospan Ltd. | Implantable medical devices constructed of shape memory material |
US9597204B2 (en) | 2011-12-04 | 2017-03-21 | Endospan Ltd. | Branched stent-graft system |
US9668892B2 (en) | 2013-03-11 | 2017-06-06 | Endospan Ltd. | Multi-component stent-graft system for aortic dissections |
US9770350B2 (en) | 2012-05-15 | 2017-09-26 | Endospan Ltd. | Stent-graft with fixation elements that are radially confined for delivery |
US9839510B2 (en) | 2011-08-28 | 2017-12-12 | Endospan Ltd. | Stent-grafts with post-deployment variable radial displacement |
US9855046B2 (en) | 2011-02-17 | 2018-01-02 | Endospan Ltd. | Vascular bands and delivery systems therefor |
US9993360B2 (en) | 2013-01-08 | 2018-06-12 | Endospan Ltd. | Minimization of stent-graft migration during implantation |
USRE47403E1 (en) * | 2004-01-27 | 2019-05-28 | Roche Diabetes Care, Inc. | Calibration of sensors or measuring systems |
US10485684B2 (en) | 2014-12-18 | 2019-11-26 | Endospan Ltd. | Endovascular stent-graft with fatigue-resistant lateral tube |
US10603197B2 (en) | 2013-11-19 | 2020-03-31 | Endospan Ltd. | Stent system with radial-expansion locking |
US11272840B2 (en) * | 2016-05-16 | 2022-03-15 | University of Pittsburgh—of the Commonwealth System of Higher Education | Touch probe passively powered wireless stent antenna for implanted sensor powering and interrogation |
WO2022032283A3 (en) * | 2020-08-07 | 2022-04-07 | Alpheus Medical, Inc. | Ultrasound arrays for enhanced sonodynamic therapy for treating cancer |
US11865372B2 (en) | 2019-02-13 | 2024-01-09 | Alpheus Medical, Inc. | Methods of treating tumors with drugs |
Families Citing this family (453)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6302875B1 (en) | 1996-10-11 | 2001-10-16 | Transvascular, Inc. | Catheters and related devices for forming passageways between blood vessels or other anatomical structures |
US6723063B1 (en) | 1998-06-29 | 2004-04-20 | Ekos Corporation | Sheath for use with an ultrasound element |
US6409674B1 (en) * | 1998-09-24 | 2002-06-25 | Data Sciences International, Inc. | Implantable sensor with wireless communication |
US6231516B1 (en) * | 1997-10-14 | 2001-05-15 | Vacusense, Inc. | Endoluminal implant with therapeutic and diagnostic capability |
US6358212B1 (en) * | 1998-04-20 | 2002-03-19 | Matsushita Electric Industrial Co., Ltd. | Noninvasive continuous blood pressure measuring apparatus and a method of noninvasively measuring continuous blood pressure |
GB9816011D0 (en) * | 1998-07-22 | 1998-09-23 | Habib Nagy A | Monitoring treatment using implantable telemetric sensors |
GB9816012D0 (en) * | 1998-07-22 | 1998-09-23 | Habib Nagy A | Treatment using implantable devices |
US6042597A (en) | 1998-10-23 | 2000-03-28 | Scimed Life Systems, Inc. | Helical stent design |
US6206835B1 (en) | 1999-03-24 | 2001-03-27 | The B. F. Goodrich Company | Remotely interrogated diagnostic implant device with electrically passive sensor |
US6317615B1 (en) | 1999-04-19 | 2001-11-13 | Cardiac Pacemakers, Inc. | Method and system for reducing arterial restenosis in the presence of an intravascular stent |
US6887199B2 (en) | 1999-09-23 | 2005-05-03 | Active Signal Technologies, Inc. | Brain assessment monitor |
US6481268B1 (en) * | 1999-10-12 | 2002-11-19 | Baker Hughes, Inc. | Particle measurement by acoustic speckle |
US6727197B1 (en) | 1999-11-18 | 2004-04-27 | Foster-Miller, Inc. | Wearable transmission device |
US8241274B2 (en) | 2000-01-19 | 2012-08-14 | Medtronic, Inc. | Method for guiding a medical device |
US7181261B2 (en) * | 2000-05-15 | 2007-02-20 | Silver James H | Implantable, retrievable, thrombus minimizing sensors |
US7006858B2 (en) * | 2000-05-15 | 2006-02-28 | Silver James H | Implantable, retrievable sensors and immunosensors |
US6442413B1 (en) | 2000-05-15 | 2002-08-27 | James H. Silver | Implantable sensor |
US7769420B2 (en) * | 2000-05-15 | 2010-08-03 | Silver James H | Sensors for detecting substances indicative of stroke, ischemia, or myocardial infarction |
US7553280B2 (en) * | 2000-06-29 | 2009-06-30 | Sensors For Medicine And Science, Inc. | Implanted sensor processing system and method |
US7616997B2 (en) | 2000-09-27 | 2009-11-10 | Kieval Robert S | Devices and methods for cardiovascular reflex control via coupled electrodes |
US8086314B1 (en) * | 2000-09-27 | 2011-12-27 | Cvrx, Inc. | Devices and methods for cardiovascular reflex control |
US20080167699A1 (en) * | 2000-09-27 | 2008-07-10 | Cvrx, Inc. | Method and Apparatus for Providing Complex Tissue Stimulation Parameters |
US7623926B2 (en) | 2000-09-27 | 2009-11-24 | Cvrx, Inc. | Stimulus regimens for cardiovascular reflex control |
US7499742B2 (en) | 2001-09-26 | 2009-03-03 | Cvrx, Inc. | Electrode structures and methods for their use in cardiovascular reflex control |
US20080177365A1 (en) * | 2000-09-27 | 2008-07-24 | Cvrx, Inc. | Method and apparatus for electronically switching electrode configuration |
US7840271B2 (en) | 2000-09-27 | 2010-11-23 | Cvrx, Inc. | Stimulus regimens for cardiovascular reflex control |
US7158832B2 (en) * | 2000-09-27 | 2007-01-02 | Cvrx, Inc. | Electrode designs and methods of use for cardiovascular reflex control devices |
US6522926B1 (en) | 2000-09-27 | 2003-02-18 | Cvrx, Inc. | Devices and methods for cardiovascular reflex control |
ATE494763T1 (en) * | 2000-10-16 | 2011-01-15 | Foster Miller Inc | METHOD FOR PRODUCING A FABRIC ARTICLE WITH ELECTRONIC CIRCUIT AND FABRIC ARTICLE |
US7369890B2 (en) * | 2000-11-02 | 2008-05-06 | Cardiac Pacemakers, Inc. | Technique for discriminating between coordinated and uncoordinated cardiac rhythms |
US9107605B2 (en) * | 2000-11-17 | 2015-08-18 | Advanced Bio Prosthetic Surfaces, Ltd., A Wholly Owned Subsidiary Of Palmaz Scientific, Inc. | Device for in vivo delivery of bioactive agents and method of manufacture thereof |
US8372139B2 (en) | 2001-02-14 | 2013-02-12 | Advanced Bio Prosthetic Surfaces, Ltd. | In vivo sensor and method of making same |
US20040092186A1 (en) * | 2000-11-17 | 2004-05-13 | Patricia Wilson-Nguyen | Textile electronic connection system |
US6689117B2 (en) * | 2000-12-18 | 2004-02-10 | Cardiac Pacemakers, Inc. | Drug delivery system for implantable medical device |
US6641520B2 (en) * | 2001-01-29 | 2003-11-04 | Electro Magnetic Resources Corp. | Magnetic field generator for therapeutic applications |
US6767360B1 (en) | 2001-02-08 | 2004-07-27 | Inflow Dynamics Inc. | Vascular stent with composite structure for magnetic reasonance imaging capabilities |
US6949929B2 (en) * | 2003-06-24 | 2005-09-27 | Biophan Technologies, Inc. | Magnetic resonance imaging interference immune device |
US20050283167A1 (en) * | 2003-08-25 | 2005-12-22 | Biophan Technologies, Inc. | Medical device with an electrically conductive anti-antenna member |
US20050288753A1 (en) * | 2003-08-25 | 2005-12-29 | Biophan Technologies, Inc. | Medical device with an electrically conductive anti-antenna member |
US20070168006A1 (en) * | 2001-02-20 | 2007-07-19 | Biophan Technologies, Inc. | Medical device with an electrically conductive anti-antenna member |
US20070173911A1 (en) * | 2001-02-20 | 2007-07-26 | Biophan Technologies, Inc. | Medical device with an electrically conductive anti-antenna member |
US20070168005A1 (en) * | 2001-02-20 | 2007-07-19 | Biophan Technologies, Inc. | Medical device with an electrically conductive anti-antenna member |
US20050288750A1 (en) * | 2003-08-25 | 2005-12-29 | Biophan Technologies, Inc. | Medical device with an electrically conductive anti-antenna member |
US20050283214A1 (en) * | 2003-08-25 | 2005-12-22 | Biophan Technologies, Inc. | Medical device with an electrically conductive anti-antenna member |
WO2002071923A2 (en) * | 2001-03-12 | 2002-09-19 | Active Signal Technologies | Brain assessment monitor |
DE10113659B4 (en) * | 2001-03-21 | 2006-10-26 | Triton BioSystems Inc., Chelmsford | Metallic medical stent |
US7232460B2 (en) * | 2001-04-25 | 2007-06-19 | Xillus, Inc. | Nanodevices, microdevices and sensors on in-vivo structures and method for the same |
US20020169480A1 (en) | 2001-05-10 | 2002-11-14 | Qingsheng Zhu | Method and device for preventing plaque formation in coronary arteries |
AUPR520301A0 (en) | 2001-05-23 | 2001-06-14 | Cochlear Limited | Transceiver coil for auditory prosthesis |
US6712844B2 (en) | 2001-06-06 | 2004-03-30 | Advanced Cardiovascular Systems, Inc. | MRI compatible stent |
US7493162B2 (en) * | 2001-06-15 | 2009-02-17 | Cardiac Pacemakers, Inc. | Pulmonary vein stent for treating atrial fibrillation |
US7209783B2 (en) * | 2001-06-15 | 2007-04-24 | Cardiac Pacemakers, Inc. | Ablation stent for treating atrial fibrillation |
US6702847B2 (en) * | 2001-06-29 | 2004-03-09 | Scimed Life Systems, Inc. | Endoluminal device with indicator member for remote detection of endoleaks and/or changes in device morphology |
US7340303B2 (en) * | 2001-09-25 | 2008-03-04 | Cardiac Pacemakers, Inc. | Evoked response sensing for ischemia detection |
AU2002359576A1 (en) * | 2001-12-03 | 2003-06-17 | Ekos Corporation | Catheter with multiple ultrasound radiating members |
US20030147812A1 (en) * | 2001-12-11 | 2003-08-07 | Friedrich Ueberle | Device and methods for initiating chemical reactions and for the targeted delivery of drugs or other agents |
US6979293B2 (en) | 2001-12-14 | 2005-12-27 | Ekos Corporation | Blood flow reestablishment determination |
AU2003209287A1 (en) | 2002-01-15 | 2003-07-30 | The Regents Of The University Of California | System and method providing directional ultrasound therapy to skeletal joints |
US20030135262A1 (en) * | 2002-01-15 | 2003-07-17 | Dretler Stephen P. | Apparatus for piezo-electric reduction of concretions |
US20060030913A1 (en) * | 2002-01-18 | 2006-02-09 | Apsara Medical Corporation | System, method and apparatus for evaluating tissue temperature |
US7048756B2 (en) * | 2002-01-18 | 2006-05-23 | Apasara Medical Corporation | System, method and apparatus for evaluating tissue temperature |
US6850804B2 (en) * | 2002-01-18 | 2005-02-01 | Calfacior Corporation | System method and apparatus for localized heating of tissue |
US7819826B2 (en) | 2002-01-23 | 2010-10-26 | The Regents Of The University Of California | Implantable thermal treatment method and apparatus |
US7236821B2 (en) * | 2002-02-19 | 2007-06-26 | Cardiac Pacemakers, Inc. | Chronically-implanted device for sensing and therapy |
GB0206061D0 (en) * | 2002-03-14 | 2002-04-24 | Angiomed Ag | Metal structure compatible with MRI imaging, and method of manufacturing such a structure |
WO2003082403A2 (en) * | 2002-03-27 | 2003-10-09 | Cvrx, Inc. | Devices and methods for cardiovascular reflex control via coupled electrodes |
US7163655B2 (en) * | 2002-03-28 | 2007-01-16 | Scimed Life Systems, Inc. | Method and apparatus for extruding polymers employing microwave energy |
WO2003082547A1 (en) * | 2002-03-28 | 2003-10-09 | Scimed Life Systems, Inc. | Polymer welding using ferromagnetic particles |
US6979420B2 (en) * | 2002-03-28 | 2005-12-27 | Scimed Life Systems, Inc. | Method of molding balloon catheters employing microwave energy |
US8226629B1 (en) | 2002-04-01 | 2012-07-24 | Ekos Corporation | Ultrasonic catheter power control |
US7617005B2 (en) | 2002-04-08 | 2009-11-10 | Ardian, Inc. | Methods and apparatus for thermally-induced renal neuromodulation |
US20070135875A1 (en) | 2002-04-08 | 2007-06-14 | Ardian, Inc. | Methods and apparatus for thermally-induced renal neuromodulation |
US20070129761A1 (en) | 2002-04-08 | 2007-06-07 | Ardian, Inc. | Methods for treating heart arrhythmia |
US8150519B2 (en) | 2002-04-08 | 2012-04-03 | Ardian, Inc. | Methods and apparatus for bilateral renal neuromodulation |
US9636174B2 (en) | 2002-04-08 | 2017-05-02 | Medtronic Ardian Luxembourg S.A.R.L. | Methods for therapeutic renal neuromodulation |
US20080213331A1 (en) | 2002-04-08 | 2008-09-04 | Ardian, Inc. | Methods and devices for renal nerve blocking |
US8086296B2 (en) * | 2002-04-30 | 2011-12-27 | Brainsonix Corporation | Methods for modifying electrical currents in neuronal circuits |
US9592409B2 (en) * | 2002-04-30 | 2017-03-14 | The Regents Of The University Of California | Methods for modifying electrical currents in neuronal circuits |
DE10223196B4 (en) | 2002-05-24 | 2004-05-13 | Dornier Medtech Systems Gmbh | Method and device for transferring molecules into cells |
US7175611B2 (en) * | 2002-06-05 | 2007-02-13 | Mark Alan Mitchnick | Antimicrobial release system |
US7261733B1 (en) * | 2002-06-07 | 2007-08-28 | Endovascular Technologies, Inc. | Endovascular graft with sensors design and attachment methods |
US7025778B2 (en) * | 2002-06-07 | 2006-04-11 | Endovascular Technologies, Inc. | Endovascular graft with pressure, temperature, flow and voltage sensors |
US7488345B2 (en) * | 2002-06-07 | 2009-02-10 | Endovascular Technologies, Inc. | Endovascular graft with pressor and attachment methods |
CA2494989A1 (en) * | 2002-08-07 | 2004-02-19 | Cardiomems, Inc. | Implantable wireless sensor for blood pressure measurement within an artery |
US7702395B2 (en) | 2002-08-19 | 2010-04-20 | Arizona Board Of Regents, A Body Corporate, Acting For And On Behalf Of Arizona State University | Neurostimulator |
US6907884B2 (en) | 2002-09-30 | 2005-06-21 | Depay Acromed, Inc. | Method of straddling an intraosseous nerve |
US8361067B2 (en) | 2002-09-30 | 2013-01-29 | Relievant Medsystems, Inc. | Methods of therapeutically heating a vertebral body to treat back pain |
US7258690B2 (en) | 2003-03-28 | 2007-08-21 | Relievant Medsystems, Inc. | Windowed thermal ablation probe |
US7615010B1 (en) * | 2002-10-03 | 2009-11-10 | Integrated Sensing Systems, Inc. | System for monitoring the physiologic parameters of patients with congestive heart failure |
WO2004034900A1 (en) * | 2002-10-15 | 2004-04-29 | Janssen Pharmaceutica N.V. | Animal model to evaluate visceral pain perception |
US20040082867A1 (en) * | 2002-10-29 | 2004-04-29 | Pearl Technology Holdings, Llc | Vascular graft with integrated sensor |
US7072711B2 (en) * | 2002-11-12 | 2006-07-04 | Cardiac Pacemakers, Inc. | Implantable device for delivering cardiac drug therapy |
AU2003279515A1 (en) * | 2002-11-14 | 2004-06-03 | Brainsgate Ltd. | Stimulation circuitry and control of electronic medical device |
US8862204B2 (en) | 2002-11-18 | 2014-10-14 | Mediguide Ltd. | Reducing mechanical stress on conductors and connection points in a position determinable interventional medical device |
US7881769B2 (en) * | 2002-11-18 | 2011-02-01 | Mediguide Ltd. | Method and system for mounting an MPS sensor on a catheter |
AU2003276673A1 (en) * | 2002-11-18 | 2004-06-15 | Mediguide Ltd. | Method and system for mounting an mps sensor on a catheter |
NL1021969C2 (en) * | 2002-11-21 | 2004-05-26 | Eugene Christian Olgers | Device for introduction into a human body. |
US6918869B2 (en) * | 2002-12-02 | 2005-07-19 | Scimed Life Systems | System for administering a combination of therapies to a body lumen |
WO2004058105A2 (en) * | 2002-12-16 | 2004-07-15 | The Regents Of The University Of Michigan | Assembly and planar structure for use therein which is expandable into a 3-d structure such as a stent and device for making the planar structure |
US7452334B2 (en) * | 2002-12-16 | 2008-11-18 | The Regents Of The University Of Michigan | Antenna stent device for wireless, intraluminal monitoring |
EP1583569A4 (en) * | 2003-01-03 | 2009-05-06 | Ekos Corp | Ultrasonic catheter with axial energy field |
US7972371B2 (en) * | 2003-01-31 | 2011-07-05 | Koninklijke Philips Electronics N.V. | Magnetic resonance compatible stent |
US7172624B2 (en) * | 2003-02-06 | 2007-02-06 | Boston Scientific Scimed, Inc. | Medical device with magnetic resonance visibility enhancing structure |
US7618435B2 (en) * | 2003-03-04 | 2009-11-17 | Nmt Medical, Inc. | Magnetic attachment systems |
US8862203B2 (en) * | 2003-03-27 | 2014-10-14 | Boston Scientific Scimed Inc. | Medical device with temperature modulator for use in magnetic resonance imaging |
US20060111626A1 (en) * | 2003-03-27 | 2006-05-25 | Cvrx, Inc. | Electrode structures having anti-inflammatory properties and methods of use |
US8239045B2 (en) | 2003-06-04 | 2012-08-07 | Synecor Llc | Device and method for retaining a medical device within a vessel |
US7617007B2 (en) * | 2003-06-04 | 2009-11-10 | Synecor Llc | Method and apparatus for retaining medical implants within body vessels |
US7529589B2 (en) * | 2003-06-04 | 2009-05-05 | Synecor Llc | Intravascular electrophysiological system and methods |
US7082336B2 (en) * | 2003-06-04 | 2006-07-25 | Synecor, Llc | Implantable intravascular device for defibrillation and/or pacing |
US7388378B2 (en) * | 2003-06-24 | 2008-06-17 | Medtronic, Inc. | Magnetic resonance imaging interference immune device |
US7839146B2 (en) | 2003-06-24 | 2010-11-23 | Medtronic, Inc. | Magnetic resonance imaging interference immune device |
US20050027175A1 (en) * | 2003-07-31 | 2005-02-03 | Zhongping Yang | Implantable biosensor |
US7882750B2 (en) * | 2003-08-01 | 2011-02-08 | Cidra Corporate Services, Inc. | Method and apparatus for measuring parameters of a fluid flowing within a pipe using a configurable array of sensors |
WO2005012843A2 (en) * | 2003-08-01 | 2005-02-10 | Cidra Corporation | Method and apparatus for measuring parameters of a fluid flowing within a pipe using a configurable array of sensors |
US7479157B2 (en) * | 2003-08-07 | 2009-01-20 | Boston Scientific Scimed, Inc. | Stent designs which enable the visibility of the inside of the stent during MRI |
US20050038497A1 (en) * | 2003-08-11 | 2005-02-17 | Scimed Life Systems, Inc. | Deformation medical device without material deformation |
US20050038331A1 (en) * | 2003-08-14 | 2005-02-17 | Grayson Silaski | Insertable sensor assembly having a coupled inductor communicative system |
US20050050042A1 (en) * | 2003-08-20 | 2005-03-03 | Marvin Elder | Natural language database querying |
US7320675B2 (en) | 2003-08-21 | 2008-01-22 | Cardiac Pacemakers, Inc. | Method and apparatus for modulating cellular metabolism during post-ischemia or heart failure |
US7559902B2 (en) * | 2003-08-22 | 2009-07-14 | Foster-Miller, Inc. | Physiological monitoring garment |
US20050288756A1 (en) * | 2003-08-25 | 2005-12-29 | Biophan Technologies, Inc. | Medical device with an electrically conductive anti-antenna member |
US20050288755A1 (en) * | 2003-08-25 | 2005-12-29 | Biophan Technologies, Inc. | Medical device with an electrically conductive anti-antenna member |
US20050288751A1 (en) * | 2003-08-25 | 2005-12-29 | Biophan Technologies, Inc. | Medical device with an electrically conductive anti-antenna member |
US20050049481A1 (en) * | 2003-08-25 | 2005-03-03 | Biophan Technologies, Inc. | Electromagnetic radiation transparent device and method of making thereof |
US20050283213A1 (en) * | 2003-08-25 | 2005-12-22 | Biophan Technologies, Inc. | Medical device with an electrically conductive anti-antenna member |
US20050288752A1 (en) * | 2003-08-25 | 2005-12-29 | Biophan Technologies, Inc. | Medical device with an electrically conductive anti-antenna member |
US20050288754A1 (en) * | 2003-08-25 | 2005-12-29 | Biophan Technologies, Inc. | Medical device with an electrically conductive anti-antenna member |
US8868212B2 (en) * | 2003-08-25 | 2014-10-21 | Medtronic, Inc. | Medical device with an electrically conductive anti-antenna member |
US7630747B2 (en) * | 2003-09-09 | 2009-12-08 | Keimar, Inc. | Apparatus for ascertaining blood characteristics and probe for use therewith |
EP3045136B1 (en) * | 2003-09-12 | 2021-02-24 | Vessix Vascular, Inc. | Selectable eccentric remodeling and/or ablation of atherosclerotic material |
US20060287590A1 (en) * | 2003-09-18 | 2006-12-21 | Mceowen Edwin L | Noninvasive vital sign measurement device |
US20050065437A1 (en) * | 2003-09-24 | 2005-03-24 | Scimed Life Systems, Inc. | Medical device with markers for magnetic resonance visibility |
WO2005031909A1 (en) * | 2003-09-30 | 2005-04-07 | Koninklijke Philips Electronics, N.V. | Electroacoustic cable for magnetic resonance applications |
US20050085895A1 (en) * | 2003-10-15 | 2005-04-21 | Scimed Life Systems, Inc. | RF-based markers for MRI visualization of medical devices |
US7480532B2 (en) | 2003-10-22 | 2009-01-20 | Cvrx, Inc. | Baroreflex activation for pain control, sedation and sleep |
DE10357334A1 (en) * | 2003-12-05 | 2005-07-07 | Grönemeyer, Dietrich H. W., Prof. Dr.med. | MR compatible medical implant |
EP1701766A2 (en) * | 2003-12-12 | 2006-09-20 | Synecor, LLC | Implantable medical device having pre-implant exoskeleton |
US7004965B2 (en) * | 2003-12-17 | 2006-02-28 | Yosef Gross | Implant and delivery tool therefor |
US8060207B2 (en) | 2003-12-22 | 2011-11-15 | Boston Scientific Scimed, Inc. | Method of intravascularly delivering stimulation leads into direct contact with tissue |
US20050137646A1 (en) * | 2003-12-22 | 2005-06-23 | Scimed Life Systems, Inc. | Method of intravascularly delivering stimulation leads into brain |
WO2005067817A1 (en) * | 2004-01-13 | 2005-07-28 | Remon Medical Technologies Ltd | Devices for fixing a sensor in a body lumen |
US20050209578A1 (en) * | 2004-01-29 | 2005-09-22 | Christian Evans Edward A | Ultrasonic catheter with segmented fluid delivery |
EP1713537A4 (en) * | 2004-01-29 | 2009-04-29 | Ekos Corp | Method and apparatus for detecting vascular conditions with a catheter |
US7201737B2 (en) * | 2004-01-29 | 2007-04-10 | Ekos Corporation | Treatment of vascular occlusions using elevated temperatures |
WO2005077450A2 (en) * | 2004-02-10 | 2005-08-25 | Synecor, Llc | Intravascular delivery system for therapeutic agents |
CN1942140A (en) * | 2004-02-11 | 2007-04-04 | 伊西康公司 | System and method for urodynamic evaluation utilizing micro-electronic mechanical system |
US8751003B2 (en) * | 2004-02-11 | 2014-06-10 | Ethicon, Inc. | Conductive mesh for neurostimulation |
US7647112B2 (en) * | 2004-02-11 | 2010-01-12 | Ethicon, Inc. | System and method for selectively stimulating different body parts |
US7979137B2 (en) | 2004-02-11 | 2011-07-12 | Ethicon, Inc. | System and method for nerve stimulation |
US8165695B2 (en) * | 2004-02-11 | 2012-04-24 | Ethicon, Inc. | System and method for selectively stimulating different body parts |
US20050182474A1 (en) * | 2004-02-13 | 2005-08-18 | Medtronic Vascular, Inc. | Coated stent having protruding crowns and elongated struts |
US7295875B2 (en) * | 2004-02-20 | 2007-11-13 | Boston Scientific Scimed, Inc. | Method of stimulating/sensing brain with combination of intravascularly and non-vascularly delivered leads |
US7840263B2 (en) | 2004-02-27 | 2010-11-23 | Cardiac Pacemakers, Inc. | Method and apparatus for device controlled gene expression |
US7590454B2 (en) | 2004-03-12 | 2009-09-15 | Boston Scientific Neuromodulation Corporation | Modular stimulation lead network |
US7177702B2 (en) | 2004-03-12 | 2007-02-13 | Scimed Life Systems, Inc. | Collapsible/expandable electrode leads |
US20050203600A1 (en) | 2004-03-12 | 2005-09-15 | Scimed Life Systems, Inc. | Collapsible/expandable tubular electrode leads |
US7231260B2 (en) * | 2004-05-06 | 2007-06-12 | Boston Scientific Scimed, Inc. | Intravascular self-anchoring electrode body with arcuate springs, spring loops, or arms |
DE102004023527A1 (en) * | 2004-05-13 | 2005-12-08 | Osypka, Peter, Dr.-Ing. | measuring device |
US7892191B2 (en) * | 2004-05-18 | 2011-02-22 | Jona Zumeris | Nanovibration coating process for medical devices using multi vibration modes of a thin piezo element |
US7764995B2 (en) | 2004-06-07 | 2010-07-27 | Cardiac Pacemakers, Inc. | Method and apparatus to modulate cellular regeneration post myocardial infarct |
EP1753340A1 (en) * | 2004-06-07 | 2007-02-21 | Radi Medical Systems Ab | Powering a guide wire mounted sensor for intra-vascular measurements of physiological variables by means of inductive coupling |
US20050278017A1 (en) * | 2004-06-09 | 2005-12-15 | Scimed Life Systems, Inc. | Overlapped stents for scaffolding, flexibility and MRI compatibility |
US20050277839A1 (en) * | 2004-06-10 | 2005-12-15 | Honeywell International, Inc. | Wireless flow measurement in arterial stent |
US7361190B2 (en) * | 2004-06-29 | 2008-04-22 | Micardia Corporation | Adjustable cardiac valve implant with coupling mechanism |
US20060004417A1 (en) * | 2004-06-30 | 2006-01-05 | Cvrx, Inc. | Baroreflex activation for arrhythmia treatment |
US7286879B2 (en) | 2004-07-16 | 2007-10-23 | Boston Scientific Scimed, Inc. | Method of stimulating fastigium nucleus to treat neurological disorders |
US8278799B1 (en) * | 2004-07-27 | 2012-10-02 | Vincent Lupien | System and method for optimizing the design of an ultrasonic transducer |
US7828711B2 (en) * | 2004-08-16 | 2010-11-09 | Cardiac Pacemakers, Inc. | Method and apparatus for modulating cellular growth and regeneration using ventricular assist device |
US20070299325A1 (en) * | 2004-08-20 | 2007-12-27 | Brian Farrell | Physiological status monitoring system |
US7567841B2 (en) * | 2004-08-20 | 2009-07-28 | Cardiac Pacemakers, Inc. | Method and apparatus for delivering combined electrical and drug therapies |
WO2006024038A2 (en) * | 2004-08-27 | 2006-03-02 | Codman & Shurtleff | Light-based implant for treating alzheimer’s disease |
US9713730B2 (en) | 2004-09-10 | 2017-07-25 | Boston Scientific Scimed, Inc. | Apparatus and method for treatment of in-stent restenosis |
US8920414B2 (en) | 2004-09-10 | 2014-12-30 | Vessix Vascular, Inc. | Tuned RF energy and electrical tissue characterization for selective treatment of target tissues |
US8396548B2 (en) | 2008-11-14 | 2013-03-12 | Vessix Vascular, Inc. | Selective drug delivery in a lumen |
US7918800B1 (en) * | 2004-10-08 | 2011-04-05 | Endovascular Technologies, Inc. | Aneurysm sensing devices and delivery systems |
EP1811894A2 (en) * | 2004-11-04 | 2007-08-01 | L & P 100 Limited | Medical devices |
US20060184070A1 (en) * | 2004-11-12 | 2006-08-17 | Hansmann Douglas R | External ultrasonic therapy |
US20060122522A1 (en) * | 2004-12-03 | 2006-06-08 | Abhi Chavan | Devices and methods for positioning and anchoring implantable sensor devices |
EP1819304B1 (en) | 2004-12-09 | 2023-01-25 | Twelve, Inc. | Aortic valve repair |
US7937160B2 (en) * | 2004-12-10 | 2011-05-03 | Boston Scientific Neuromodulation Corporation | Methods for delivering cortical electrode leads into patient's head |
US20060173387A1 (en) * | 2004-12-10 | 2006-08-03 | Douglas Hansmann | Externally enhanced ultrasonic therapy |
JP4804906B2 (en) | 2004-12-15 | 2011-11-02 | ドルニエル メドテック システムズ ゲーエムベーハー | Shock wave improved methods of cell therapy and tissue regeneration in patients with cardiovascular and neurological diseases |
US8060219B2 (en) | 2004-12-20 | 2011-11-15 | Cardiac Pacemakers, Inc. | Epicardial patch including isolated extracellular matrix with pacing electrodes |
US7981065B2 (en) | 2004-12-20 | 2011-07-19 | Cardiac Pacemakers, Inc. | Lead electrode incorporating extracellular matrix |
US7318838B2 (en) * | 2004-12-31 | 2008-01-15 | Boston Scientific Scimed, Inc. | Smart textile vascular graft |
US7295874B2 (en) | 2005-01-06 | 2007-11-13 | Cardiac Pacemakers, Inc. | Intermittent stress augmentation pacing for cardioprotective effect |
US10390714B2 (en) * | 2005-01-12 | 2019-08-27 | Remon Medical Technologies, Ltd. | Devices for fixing a sensor in a lumen |
US8066759B2 (en) * | 2005-02-04 | 2011-11-29 | Boston Scientific Scimed, Inc. | Resonator for medical device |
US8267954B2 (en) * | 2005-02-04 | 2012-09-18 | C. R. Bard, Inc. | Vascular filter with sensing capability |
USRE47266E1 (en) | 2005-03-14 | 2019-03-05 | DePuy Synthes Products, Inc. | Light-based implants for treating Alzheimer's disease |
US7288108B2 (en) * | 2005-03-14 | 2007-10-30 | Codman & Shurtleff, Inc. | Red light implant for treating Parkinson's disease |
CN101511292B (en) * | 2005-03-28 | 2011-04-06 | 明诺医学有限公司 | Intraluminal electrical tissue characterization and tuned RF energy for selective treatment of atheroma and other target tissues |
TWI319565B (en) * | 2005-04-01 | 2010-01-11 | Qualcomm Inc | Methods, and apparatus for generating highband excitation signal |
US7499748B2 (en) * | 2005-04-11 | 2009-03-03 | Cardiac Pacemakers, Inc. | Transvascular neural stimulation device |
US20060235349A1 (en) * | 2005-04-14 | 2006-10-19 | Brett Osborn | Implantable anti-clogging device for maintenance of cerebrospinal fluid shunt patency |
US20060253026A1 (en) * | 2005-05-04 | 2006-11-09 | Siemens Medical Solutions Usa, Inc. | Transducer for multi-purpose ultrasound |
US20060259088A1 (en) * | 2005-05-13 | 2006-11-16 | Pastore Joseph M | Method and apparatus for delivering pacing pulses using a coronary stent |
US7617003B2 (en) * | 2005-05-16 | 2009-11-10 | Cardiac Pacemakers, Inc. | System for selective activation of a nerve trunk using a transvascular reshaping lead |
US20070010896A1 (en) * | 2005-05-19 | 2007-01-11 | Biophan Technologies, Inc. | Electromagnetic resonant circuit sleeve for implantable medical device |
US7595469B2 (en) * | 2005-05-24 | 2009-09-29 | Boston Scientific Scimed, Inc. | Resonator for medical device |
EP1887925A2 (en) * | 2005-05-27 | 2008-02-20 | The Cleveland Clinic Foundation | Method and apparatus for eddy current compensation in a radio frequency probe |
US8588930B2 (en) * | 2005-06-07 | 2013-11-19 | Ethicon, Inc. | Piezoelectric stimulation device |
US7351253B2 (en) * | 2005-06-16 | 2008-04-01 | Codman & Shurtleff, Inc. | Intranasal red light probe for treating Alzheimer's disease |
US7295879B2 (en) * | 2005-06-24 | 2007-11-13 | Kenergy, Inc. | Double helical antenna assembly for a wireless intravascular medical device |
US20110118773A1 (en) * | 2005-07-25 | 2011-05-19 | Rainbow Medical Ltd. | Elliptical device for treating afterload |
WO2007013065A2 (en) | 2005-07-25 | 2007-02-01 | Rainbow Medical Ltd. | Electrical stimulation of blood vessels |
US7279664B2 (en) * | 2005-07-26 | 2007-10-09 | Boston Scientific Scimed, Inc. | Resonator for medical device |
DE202005012982U1 (en) * | 2005-08-17 | 2005-10-27 | Odu-Steckverbindungssysteme Gmbh & Co. Kg | In line electrical connector has a plug with spring arm formed lugs that latch into holes in socket body to secure |
US7304277B2 (en) * | 2005-08-23 | 2007-12-04 | Boston Scientific Scimed, Inc | Resonator with adjustable capacitor for medical device |
US7524282B2 (en) * | 2005-08-29 | 2009-04-28 | Boston Scientific Scimed, Inc. | Cardiac sleeve apparatus, system and method of use |
WO2007030433A2 (en) * | 2005-09-06 | 2007-03-15 | Nmt Medical, Inc. | Removable intracardiac rf device |
US9259267B2 (en) | 2005-09-06 | 2016-02-16 | W.L. Gore & Associates, Inc. | Devices and methods for treating cardiac tissue |
US7616990B2 (en) | 2005-10-24 | 2009-11-10 | Cardiac Pacemakers, Inc. | Implantable and rechargeable neural stimulator |
US7423496B2 (en) * | 2005-11-09 | 2008-09-09 | Boston Scientific Scimed, Inc. | Resonator with adjustable capacitance for medical device |
US9028415B2 (en) * | 2005-11-16 | 2015-05-12 | Cook Medical Technologies Llc | Blood flow monitor with visual display |
US8108034B2 (en) | 2005-11-28 | 2012-01-31 | Cardiac Pacemakers, Inc. | Systems and methods for valvular regurgitation detection |
WO2007066343A2 (en) * | 2005-12-08 | 2007-06-14 | Dan Furman | Implantable biosensor assembly and health monitoring system |
IL185609A0 (en) * | 2007-08-30 | 2008-01-06 | Dan Furman | Multi function senssor |
WO2007075593A1 (en) * | 2005-12-20 | 2007-07-05 | The Cleveland Clinic Foundation | Apparatus and method for modulating the baroreflex system |
US7885710B2 (en) * | 2005-12-23 | 2011-02-08 | Cardiac Pacemakers, Inc. | Method and apparatus for tissue protection against ischemia using remote conditioning |
US8060214B2 (en) * | 2006-01-05 | 2011-11-15 | Cardiac Pacemakers, Inc. | Implantable medical device with inductive coil configurable for mechanical fixation |
US8109879B2 (en) * | 2006-01-10 | 2012-02-07 | Cardiac Pacemakers, Inc. | Assessing autonomic activity using baroreflex analysis |
WO2007092330A1 (en) * | 2006-02-03 | 2007-08-16 | Synecor, Llc | Intravascular device for neuromodulation |
US8019435B2 (en) | 2006-05-02 | 2011-09-13 | Boston Scientific Scimed, Inc. | Control of arterial smooth muscle tone |
US20080039746A1 (en) | 2006-05-25 | 2008-02-14 | Medtronic, Inc. | Methods of using high intensity focused ultrasound to form an ablated tissue area containing a plurality of lesions |
WO2007140389A2 (en) * | 2006-05-30 | 2007-12-06 | Biophan Technologies, Inc. | Magnetic resonance imaging stent having inter-luminal compatibility with magnetic resonance imaging |
US8968204B2 (en) * | 2006-06-12 | 2015-03-03 | Transonic Systems, Inc. | System and method of perivascular pressure and flow measurement |
CN101588826A (en) * | 2006-08-02 | 2009-11-25 | 英孚拉玛特公司 | Lumen-supporting devices and methods of making and using |
WO2008016712A2 (en) * | 2006-08-02 | 2008-02-07 | Inframat Corporation | Medical devices and methods of making and using |
US20080071248A1 (en) * | 2006-09-15 | 2008-03-20 | Cardiac Pacemakers, Inc. | Delivery stystem for an implantable physiologic sensor |
US8676349B2 (en) * | 2006-09-15 | 2014-03-18 | Cardiac Pacemakers, Inc. | Mechanism for releasably engaging an implantable medical device for implantation |
JP5156749B2 (en) * | 2006-09-15 | 2013-03-06 | カーディアック ペースメイカーズ, インコーポレイテッド | Implantable sensor anchor |
EP2992850A1 (en) | 2006-10-18 | 2016-03-09 | Vessix Vascular, Inc. | Inducing desirable temperature effects on body tissue |
EP2076194B1 (en) | 2006-10-18 | 2013-04-24 | Vessix Vascular, Inc. | System for inducing desirable temperature effects on body tissue |
EP2076170B1 (en) * | 2006-10-20 | 2015-04-01 | CardioMems, Inc. | Apparatus for measuring pressure inside a fluid system |
US8192363B2 (en) | 2006-10-27 | 2012-06-05 | Ekos Corporation | Catheter with multiple ultrasound radiating members |
WO2008057478A2 (en) * | 2006-11-03 | 2008-05-15 | The Regents Of The University Of Michigan | Method and system for determining volume flow in a blood conduit |
WO2008070189A2 (en) | 2006-12-06 | 2008-06-12 | The Cleveland Clinic Foundation | Method and system for treating acute heart failure by neuromodulation |
US8768486B2 (en) * | 2006-12-11 | 2014-07-01 | Medtronic, Inc. | Medical leads with frequency independent magnetic resonance imaging protection |
US10182833B2 (en) | 2007-01-08 | 2019-01-22 | Ekos Corporation | Power parameters for ultrasonic catheter |
WO2008089282A2 (en) | 2007-01-16 | 2008-07-24 | Silver James H | Sensors for detecting subtances indicative of stroke, ischemia, infection or inflammation |
PT2167194T (en) * | 2007-03-06 | 2017-06-15 | Novocure Ltd | Treating cancer using electromagnetic fields in combination with photodynamic therapy |
US8249705B1 (en) | 2007-03-20 | 2012-08-21 | Cvrx, Inc. | Devices, systems, and methods for improving left ventricular structure and function using baroreflex activation therapy |
US8496653B2 (en) | 2007-04-23 | 2013-07-30 | Boston Scientific Scimed, Inc. | Thrombus removal |
US8204599B2 (en) | 2007-05-02 | 2012-06-19 | Cardiac Pacemakers, Inc. | System for anchoring an implantable sensor in a vessel |
JP2010525901A (en) * | 2007-05-04 | 2010-07-29 | アリゾナ ボード オブ リージェンツ フォー アンド オン ビハーフ オブ アリゾナ ステイト ユニバーシティ | System and method for wireless transmission of biopotentials |
US20080281163A1 (en) * | 2007-05-10 | 2008-11-13 | General Electric Company | Apparatus and method for acquiring medical data |
US20090132002A1 (en) * | 2007-05-11 | 2009-05-21 | Cvrx, Inc. | Baroreflex activation therapy with conditional shut off |
US20080283066A1 (en) * | 2007-05-17 | 2008-11-20 | Cardiac Pacemakers, Inc. | Delivery device for implantable sensors |
US20100130815A1 (en) * | 2007-05-18 | 2010-05-27 | Prostaplant Ltd. | Intraurethral and extraurethral apparatus |
CA2687876A1 (en) * | 2007-05-23 | 2009-03-05 | Oscillon Ltd. | Apparatus and method for guided chronic total occlusion penetration |
US9162073B2 (en) * | 2007-05-30 | 2015-10-20 | The Cleveland Clinic Foundation | Method for treating erectile dysfunction |
WO2008156981A2 (en) | 2007-06-14 | 2008-12-24 | Cardiac Pacemakers, Inc. | Multi-element acoustic recharging system |
EP2494932B1 (en) | 2007-06-22 | 2020-05-20 | Ekos Corporation | Apparatus for treatment of intracranial hemorrhages |
US20090025459A1 (en) * | 2007-07-23 | 2009-01-29 | Cardiac Pacemakers, Inc. | Implantable viscosity monitoring device and method therefor |
US8594794B2 (en) | 2007-07-24 | 2013-11-26 | Cvrx, Inc. | Baroreflex activation therapy with incrementally changing intensity |
US7979108B2 (en) * | 2007-08-27 | 2011-07-12 | William Harrison Zurn | Automated vessel repair system, devices and methods |
US20090062724A1 (en) * | 2007-08-31 | 2009-03-05 | Rixen Chen | System and apparatus for sonodynamic therapy |
US8352026B2 (en) * | 2007-10-03 | 2013-01-08 | Ethicon, Inc. | Implantable pulse generators and methods for selective nerve stimulation |
EP2254660A1 (en) * | 2008-01-29 | 2010-12-01 | Cardiac Pacemakers, Inc. | Configurable intermittent pacing therapy |
US8538535B2 (en) | 2010-08-05 | 2013-09-17 | Rainbow Medical Ltd. | Enhancing perfusion by contraction |
US9005106B2 (en) | 2008-01-31 | 2015-04-14 | Enopace Biomedical Ltd | Intra-aortic electrical counterpulsation |
US9320914B2 (en) * | 2008-03-03 | 2016-04-26 | DePuy Synthes Products, Inc. | Endoscopic delivery of red/NIR light to the subventricular zone |
US7925352B2 (en) | 2008-03-27 | 2011-04-12 | Synecor Llc | System and method for transvascularly stimulating contents of the carotid sheath |
US8239037B2 (en) * | 2008-07-06 | 2012-08-07 | Synecor Llc | Intravascular implant anchors having remote communication and/or battery recharging capabilities |
US20100010328A1 (en) * | 2008-07-11 | 2010-01-14 | Nguyen Harry D | Probes and sensors for ascertaining blood characteristics and methods and devices for use therewith |
JP5362828B2 (en) * | 2008-07-15 | 2013-12-11 | カーディアック ペースメイカーズ, インコーポレイテッド | Implant assist for an acoustically enabled implantable medical device |
US20100057046A1 (en) * | 2008-09-03 | 2010-03-04 | Keimar, Inc | Systems for characterizing physiologic parameters and methods for use therewith |
US10028753B2 (en) | 2008-09-26 | 2018-07-24 | Relievant Medsystems, Inc. | Spine treatment kits |
EP2339972B1 (en) | 2008-09-26 | 2018-04-11 | Relievant Medsystems, Inc. | Systems for navigating an instrument through bone |
CA2741206C (en) * | 2008-11-03 | 2016-01-12 | G.I. View Ltd | Remote pressure sensing system and method thereof |
US9795442B2 (en) | 2008-11-11 | 2017-10-24 | Shifamed Holdings, Llc | Ablation catheters |
CA2743992A1 (en) | 2008-11-17 | 2010-05-20 | Minnow Medical, Inc. | Selective accumulation of energy with or without knowledge of tissue topography |
US9759202B2 (en) | 2008-12-04 | 2017-09-12 | Deep Science, Llc | Method for generation of power from intraluminal pressure changes |
US9567983B2 (en) | 2008-12-04 | 2017-02-14 | Deep Science, Llc | Method for generation of power from intraluminal pressure changes |
US9526418B2 (en) | 2008-12-04 | 2016-12-27 | Deep Science, Llc | Device for storage of intraluminally generated power |
US9631610B2 (en) | 2008-12-04 | 2017-04-25 | Deep Science, Llc | System for powering devices from intraluminal pressure changes |
US9353733B2 (en) | 2008-12-04 | 2016-05-31 | Deep Science, Llc | Device and system for generation of power from intraluminal pressure changes |
US20100160906A1 (en) * | 2008-12-23 | 2010-06-24 | Asthmatx, Inc. | Expandable energy delivery devices having flexible conductive elements and associated systems and methods |
US20100198316A1 (en) * | 2009-02-04 | 2010-08-05 | Richard Toselli | Intracranial Red Light Treatment Device For Chronic Pain |
WO2010093489A2 (en) * | 2009-02-13 | 2010-08-19 | Cardiac Pacemakers, Inc. | Deployable sensor platform on the lead system of an implantable device |
US8551096B2 (en) | 2009-05-13 | 2013-10-08 | Boston Scientific Scimed, Inc. | Directional delivery of energy and bioactives |
US20100317978A1 (en) * | 2009-06-10 | 2010-12-16 | Maile Keith R | Implantable medical device housing modified for piezoelectric energy harvesting |
US8506495B2 (en) * | 2009-06-10 | 2013-08-13 | Cardiac Pacemakers, Inc. | Implantable medical devices with piezoelectric anchoring member |
US8777863B2 (en) * | 2009-06-10 | 2014-07-15 | Cardiac Pacemakers, Inc. | Implantable medical device with internal piezoelectric energy harvesting |
US8690749B1 (en) | 2009-11-02 | 2014-04-08 | Anthony Nunez | Wireless compressible heart pump |
US8696740B2 (en) | 2010-01-05 | 2014-04-15 | The Johns Hopkins University | Implantable pressure-actuated drug delivery systems and methods of manufacture and use |
US8475525B2 (en) | 2010-01-22 | 2013-07-02 | 4Tech Inc. | Tricuspid valve repair using tension |
US9307980B2 (en) | 2010-01-22 | 2016-04-12 | 4Tech Inc. | Tricuspid valve repair using tension |
US10058323B2 (en) | 2010-01-22 | 2018-08-28 | 4 Tech Inc. | Tricuspid valve repair using tension |
CN103068330B (en) | 2010-04-09 | 2016-06-29 | Vessix血管股份有限公司 | Power for treating tissue occurs and controls device |
US9192790B2 (en) | 2010-04-14 | 2015-11-24 | Boston Scientific Scimed, Inc. | Focused ultrasonic renal denervation |
US9211085B2 (en) | 2010-05-03 | 2015-12-15 | Foster-Miller, Inc. | Respiration sensing system |
EP2568905A4 (en) | 2010-05-12 | 2017-07-26 | Shifamed Holdings, LLC | Low profile electrode assembly |
US9655677B2 (en) | 2010-05-12 | 2017-05-23 | Shifamed Holdings, Llc | Ablation catheters including a balloon and electrodes |
US8771201B2 (en) * | 2010-06-02 | 2014-07-08 | Vital Herd, Inc. | Health monitoring bolus |
US8473067B2 (en) | 2010-06-11 | 2013-06-25 | Boston Scientific Scimed, Inc. | Renal denervation and stimulation employing wireless vascular energy transfer arrangement |
EP2409664B1 (en) * | 2010-07-22 | 2013-10-30 | W & H Dentalwerk Bürmoos GmbH | Medicinal treatment device and method for regulating same |
US9028404B2 (en) | 2010-07-28 | 2015-05-12 | Foster-Miller, Inc. | Physiological status monitoring system |
US9463062B2 (en) | 2010-07-30 | 2016-10-11 | Boston Scientific Scimed, Inc. | Cooled conductive balloon RF catheter for renal nerve ablation |
US9358365B2 (en) | 2010-07-30 | 2016-06-07 | Boston Scientific Scimed, Inc. | Precision electrode movement control for renal nerve ablation |
US9408661B2 (en) | 2010-07-30 | 2016-08-09 | Patrick A. Haverkost | RF electrodes on multiple flexible wires for renal nerve ablation |
US9155589B2 (en) | 2010-07-30 | 2015-10-13 | Boston Scientific Scimed, Inc. | Sequential activation RF electrode set for renal nerve ablation |
US9084609B2 (en) | 2010-07-30 | 2015-07-21 | Boston Scientific Scime, Inc. | Spiral balloon catheter for renal nerve ablation |
WO2012149511A2 (en) | 2011-04-28 | 2012-11-01 | Synecor Llc | Neuromodulation systems and methods for treating acute heart failure syndromes |
US10022566B2 (en) | 2010-08-31 | 2018-07-17 | Arizona Board Of Regents On Behalf Of Arizona State University | Apparatus, systems, and methods for current monitoring in ultrasound powered neurostimulation |
US8585606B2 (en) | 2010-09-23 | 2013-11-19 | QinetiQ North America, Inc. | Physiological status monitoring system |
CA2813306C (en) * | 2010-10-05 | 2022-09-27 | Andrei Ghila | Image guided radiation therapy system and shielded radiofrequency detector coil for use therein |
US8974451B2 (en) | 2010-10-25 | 2015-03-10 | Boston Scientific Scimed, Inc. | Renal nerve ablation using conductive fluid jet and RF energy |
US9220558B2 (en) | 2010-10-27 | 2015-12-29 | Boston Scientific Scimed, Inc. | RF renal denervation catheter with multiple independent electrodes |
US9028485B2 (en) | 2010-11-15 | 2015-05-12 | Boston Scientific Scimed, Inc. | Self-expanding cooling electrode for renal nerve ablation |
US9089350B2 (en) | 2010-11-16 | 2015-07-28 | Boston Scientific Scimed, Inc. | Renal denervation catheter with RF electrode and integral contrast dye injection arrangement |
US9668811B2 (en) | 2010-11-16 | 2017-06-06 | Boston Scientific Scimed, Inc. | Minimally invasive access for renal nerve ablation |
US9326751B2 (en) | 2010-11-17 | 2016-05-03 | Boston Scientific Scimed, Inc. | Catheter guidance of external energy for renal denervation |
US9060761B2 (en) | 2010-11-18 | 2015-06-23 | Boston Scientific Scime, Inc. | Catheter-focused magnetic field induced renal nerve ablation |
US9023034B2 (en) | 2010-11-22 | 2015-05-05 | Boston Scientific Scimed, Inc. | Renal ablation electrode with force-activatable conduction apparatus |
US9192435B2 (en) | 2010-11-22 | 2015-11-24 | Boston Scientific Scimed, Inc. | Renal denervation catheter with cooled RF electrode |
US20120157993A1 (en) | 2010-12-15 | 2012-06-21 | Jenson Mark L | Bipolar Off-Wall Electrode Device for Renal Nerve Ablation |
US9220561B2 (en) | 2011-01-19 | 2015-12-29 | Boston Scientific Scimed, Inc. | Guide-compatible large-electrode catheter for renal nerve ablation with reduced arterial injury |
DE102011009020B4 (en) * | 2011-01-20 | 2022-03-17 | Acandis Gmbh | Hearing prosthesis and method for producing such a hearing prosthesis |
CA2832311A1 (en) | 2011-04-08 | 2012-11-29 | Covidien Lp | Iontophoresis drug delivery system and method for denervation of the renal sympathetic nerve and iontophoretic drug delivery |
US11458290B2 (en) | 2011-05-11 | 2022-10-04 | Ekos Corporation | Ultrasound system |
US9446240B2 (en) | 2011-07-11 | 2016-09-20 | Interventional Autonomics Corporation | System and method for neuromodulation |
EP2731671B1 (en) | 2011-07-11 | 2019-04-03 | Interventional Autonomics Corporation | Catheter system for acute neuromodulation |
US20130072995A1 (en) | 2011-07-11 | 2013-03-21 | Terrance Ransbury | Catheter system for acute neuromodulation |
CN103813745B (en) | 2011-07-20 | 2016-06-29 | 波士顿科学西美德公司 | In order to visualize, be directed at and to melt transcutaneous device and the method for nerve |
WO2013011502A2 (en) | 2011-07-21 | 2013-01-24 | 4Tech Inc. | Method and apparatus for tricuspid valve repair using tension |
CN103813829B (en) | 2011-07-22 | 2016-05-18 | 波士顿科学西美德公司 | There is the neuromodulation system of the neuromodulation element that can be positioned in spiral guiding piece |
EP2872070B1 (en) | 2011-09-09 | 2018-02-07 | Enopace Biomedical Ltd. | Wireless endovascular stent-based electrodes |
US8855783B2 (en) | 2011-09-09 | 2014-10-07 | Enopace Biomedical Ltd. | Detector-based arterial stimulation |
WO2013055826A1 (en) | 2011-10-10 | 2013-04-18 | Boston Scientific Scimed, Inc. | Medical devices including ablation electrodes |
US9420955B2 (en) | 2011-10-11 | 2016-08-23 | Boston Scientific Scimed, Inc. | Intravascular temperature monitoring system and method |
US10085799B2 (en) | 2011-10-11 | 2018-10-02 | Boston Scientific Scimed, Inc. | Off-wall electrode device and methods for nerve modulation |
US9364284B2 (en) | 2011-10-12 | 2016-06-14 | Boston Scientific Scimed, Inc. | Method of making an off-wall spacer cage |
EP2768568B1 (en) | 2011-10-18 | 2020-05-06 | Boston Scientific Scimed, Inc. | Integrated crossing balloon catheter |
EP2768563B1 (en) | 2011-10-18 | 2016-11-09 | Boston Scientific Scimed, Inc. | Deflectable medical devices |
CN108095821B (en) | 2011-11-08 | 2021-05-25 | 波士顿科学西美德公司 | Orifice renal nerve ablation |
WO2013071290A1 (en) | 2011-11-13 | 2013-05-16 | Arizona Board Of Regents For And On Behalf Of Arizona State University | Controlled stimulation delivery from neurostimulator |
US9119600B2 (en) | 2011-11-15 | 2015-09-01 | Boston Scientific Scimed, Inc. | Device and methods for renal nerve modulation monitoring |
US9119632B2 (en) | 2011-11-21 | 2015-09-01 | Boston Scientific Scimed, Inc. | Deflectable renal nerve ablation catheter |
US9265969B2 (en) | 2011-12-21 | 2016-02-23 | Cardiac Pacemakers, Inc. | Methods for modulating cell function |
EP2793724B1 (en) | 2011-12-23 | 2016-10-12 | Vessix Vascular, Inc. | Apparatuses for remodeling tissue of or adjacent to a body passage |
CN104135958B (en) | 2011-12-28 | 2017-05-03 | 波士顿科学西美德公司 | By the apparatus and method that have the new ablation catheter modulation nerve of polymer ablation |
US9050106B2 (en) | 2011-12-29 | 2015-06-09 | Boston Scientific Scimed, Inc. | Off-wall electrode device and methods for nerve modulation |
WO2013101772A1 (en) | 2011-12-30 | 2013-07-04 | Relievant Medsystems, Inc. | Systems and methods for treating back pain |
US8663209B2 (en) | 2012-01-24 | 2014-03-04 | William Harrison Zurn | Vessel clearing apparatus, devices and methods |
US9386991B2 (en) | 2012-02-02 | 2016-07-12 | Rainbow Medical Ltd. | Pressure-enhanced blood flow treatment |
WO2013164829A1 (en) * | 2012-05-02 | 2013-11-07 | Enopace Biomedical Ltd. | Wireless endovascular stent-based electrodes |
WO2013169927A1 (en) | 2012-05-08 | 2013-11-14 | Boston Scientific Scimed, Inc. | Renal nerve modulation devices |
US8961594B2 (en) | 2012-05-31 | 2015-02-24 | 4Tech Inc. | Heart valve repair system |
US9772317B2 (en) | 2012-07-26 | 2017-09-26 | Sensirion Ag | Method for operating a portable electronic device |
US9833207B2 (en) | 2012-08-08 | 2017-12-05 | William Harrison Zurn | Analysis and clearing module, system and method |
CN104540465A (en) | 2012-08-24 | 2015-04-22 | 波士顿科学西美德公司 | Intravascular catheter with a balloon comprising separate microporous regions |
US10588691B2 (en) | 2012-09-12 | 2020-03-17 | Relievant Medsystems, Inc. | Radiofrequency ablation of tissue within a vertebral body |
CN104780859B (en) | 2012-09-17 | 2017-07-25 | 波士顿科学西美德公司 | Self-positioning electrode system and method for renal regulation |
US10549127B2 (en) | 2012-09-21 | 2020-02-04 | Boston Scientific Scimed, Inc. | Self-cooling ultrasound ablation catheter |
WO2014047411A1 (en) | 2012-09-21 | 2014-03-27 | Boston Scientific Scimed, Inc. | System for nerve modulation and innocuous thermal gradient nerve block |
US10835305B2 (en) | 2012-10-10 | 2020-11-17 | Boston Scientific Scimed, Inc. | Renal nerve modulation devices and methods |
US9801721B2 (en) * | 2012-10-12 | 2017-10-31 | St. Jude Medical, Cardiology Division, Inc. | Sizing device and method of positioning a prosthetic heart valve |
US20140121750A1 (en) * | 2012-10-31 | 2014-05-01 | Cook Medical Technologies Llc | Fixation Process For Nesting Stents |
EP3598952A3 (en) | 2012-11-05 | 2020-04-15 | Relievant Medsystems, Inc. | Systems and methods for creating curved paths through bone and modulating nerves within the bone |
WO2014076620A2 (en) | 2012-11-14 | 2014-05-22 | Vectorious Medical Technologies Ltd. | Drift compensation for implanted capacitance-based pressure transducer |
US9061133B2 (en) | 2012-12-27 | 2015-06-23 | Brainsonix Corporation | Focused ultrasonic transducer navigation system |
US10974078B2 (en) | 2012-12-27 | 2021-04-13 | Brainsonix Corporation | Treating degenerative dementia with low intensity focused ultrasound pulsation (LIFUP) device |
US10512794B2 (en) | 2016-12-16 | 2019-12-24 | Brainsonix Corporation | Stereotactic frame |
US9788948B2 (en) | 2013-01-09 | 2017-10-17 | 4 Tech Inc. | Soft tissue anchors and implantation techniques |
US9962533B2 (en) | 2013-02-14 | 2018-05-08 | William Harrison Zurn | Module for treatment of medical conditions; system for making module and methods of making module |
US9693821B2 (en) | 2013-03-11 | 2017-07-04 | Boston Scientific Scimed, Inc. | Medical devices for modulating nerves |
WO2014163987A1 (en) | 2013-03-11 | 2014-10-09 | Boston Scientific Scimed, Inc. | Medical devices for modulating nerves |
US9808311B2 (en) | 2013-03-13 | 2017-11-07 | Boston Scientific Scimed, Inc. | Deflectable medical devices |
US9297845B2 (en) | 2013-03-15 | 2016-03-29 | Boston Scientific Scimed, Inc. | Medical devices and methods for treatment of hypertension that utilize impedance compensation |
JP6220044B2 (en) | 2013-03-15 | 2017-10-25 | ボストン サイエンティフィック サイムド,インコーポレイテッドBoston Scientific Scimed,Inc. | Medical device for renal nerve ablation |
US9233247B2 (en) * | 2013-03-15 | 2016-01-12 | Boston Scientific Neuromodulation Corporation | Neuromodulation of renal nerve for treatment of hypertension |
US10265122B2 (en) | 2013-03-15 | 2019-04-23 | Boston Scientific Scimed, Inc. | Nerve ablation devices and related methods of use |
CA2908517A1 (en) | 2013-04-08 | 2014-10-16 | Apama Medical, Inc. | Cardiac ablation catheters and methods of use thereof |
US10349824B2 (en) | 2013-04-08 | 2019-07-16 | Apama Medical, Inc. | Tissue mapping and visualization systems |
DE102013103494A1 (en) * | 2013-04-08 | 2014-10-09 | Pro-Micron Gmbh & Co. Kg | Strain gauge sensor |
US10098694B2 (en) | 2013-04-08 | 2018-10-16 | Apama Medical, Inc. | Tissue ablation and monitoring thereof |
WO2014170771A1 (en) | 2013-04-18 | 2014-10-23 | Vectorious Medical Technologies Ltd. | Remotely powered sensory implant |
US10205488B2 (en) | 2013-04-18 | 2019-02-12 | Vectorious Medical Technologies Ltd. | Low-power high-accuracy clock harvesting in inductive coupling systems |
US10022182B2 (en) | 2013-06-21 | 2018-07-17 | Boston Scientific Scimed, Inc. | Medical devices for renal nerve ablation having rotatable shafts |
JP2016523147A (en) | 2013-06-21 | 2016-08-08 | ボストン サイエンティフィック サイムド,インコーポレイテッドBoston Scientific Scimed,Inc. | Renal denervation balloon catheter with a riding-type electrode support |
US9707036B2 (en) | 2013-06-25 | 2017-07-18 | Boston Scientific Scimed, Inc. | Devices and methods for nerve modulation using localized indifferent electrodes |
WO2015002787A1 (en) | 2013-07-01 | 2015-01-08 | Boston Scientific Scimed, Inc. | Medical devices for renal nerve ablation |
EP3019105B1 (en) | 2013-07-11 | 2017-09-13 | Boston Scientific Scimed, Inc. | Devices for nerve modulation |
US10413357B2 (en) | 2013-07-11 | 2019-09-17 | Boston Scientific Scimed, Inc. | Medical device with stretchable electrode assemblies |
CN105682594B (en) | 2013-07-19 | 2018-06-22 | 波士顿科学国际有限公司 | Helical bipolar electrodes renal denervation dominates air bag |
EP3024406B1 (en) | 2013-07-22 | 2019-06-19 | Boston Scientific Scimed, Inc. | Medical devices for renal nerve ablation |
EP3024405A1 (en) | 2013-07-22 | 2016-06-01 | Boston Scientific Scimed, Inc. | Renal nerve ablation catheter having twist balloon |
US9724151B2 (en) | 2013-08-08 | 2017-08-08 | Relievant Medsystems, Inc. | Modulating nerves within bone using bone fasteners |
WO2015027096A1 (en) | 2013-08-22 | 2015-02-26 | Boston Scientific Scimed, Inc. | Flexible circuit having improved adhesion to a renal nerve modulation balloon |
US9895194B2 (en) | 2013-09-04 | 2018-02-20 | Boston Scientific Scimed, Inc. | Radio frequency (RF) balloon catheter having flushing and cooling capability |
EP3043733A1 (en) | 2013-09-13 | 2016-07-20 | Boston Scientific Scimed, Inc. | Ablation balloon with vapor deposited cover layer |
US9687166B2 (en) | 2013-10-14 | 2017-06-27 | Boston Scientific Scimed, Inc. | High resolution cardiac mapping electrode array catheter |
US11246654B2 (en) | 2013-10-14 | 2022-02-15 | Boston Scientific Scimed, Inc. | Flexible renal nerve ablation devices and related methods of use and manufacture |
US9962223B2 (en) | 2013-10-15 | 2018-05-08 | Boston Scientific Scimed, Inc. | Medical device balloon |
US9770606B2 (en) | 2013-10-15 | 2017-09-26 | Boston Scientific Scimed, Inc. | Ultrasound ablation catheter with cooling infusion and centering basket |
EP3057521B1 (en) | 2013-10-18 | 2020-03-25 | Boston Scientific Scimed, Inc. | Balloon catheters with flexible conducting wires |
US10271898B2 (en) | 2013-10-25 | 2019-04-30 | Boston Scientific Scimed, Inc. | Embedded thermocouple in denervation flex circuit |
US10052095B2 (en) | 2013-10-30 | 2018-08-21 | 4Tech Inc. | Multiple anchoring-point tension system |
US10779965B2 (en) | 2013-11-06 | 2020-09-22 | Enopace Biomedical Ltd. | Posts with compliant junctions |
EP3091922B1 (en) | 2014-01-06 | 2018-10-17 | Boston Scientific Scimed, Inc. | Tear resistant flex circuit assembly |
US11000679B2 (en) | 2014-02-04 | 2021-05-11 | Boston Scientific Scimed, Inc. | Balloon protection and rewrapping devices and related methods of use |
EP3424453A1 (en) | 2014-02-04 | 2019-01-09 | Boston Scientific Scimed, Inc. | Alternative placement of thermal sensors on bipolar electrode |
CN106659874B (en) * | 2014-03-26 | 2021-01-05 | 文科罗斯公司 | Treatment of venous diseases |
WO2015179634A2 (en) | 2014-05-22 | 2015-11-26 | CARDIONOMIC, Inc. | Catheter and catheter system for electrical neuromodulation |
US20170202691A1 (en) * | 2014-05-29 | 2017-07-20 | Arizona Board Of Regents On Behalf Of Arizona State University | Sensor-stents |
EP3157607B1 (en) | 2014-06-19 | 2019-08-07 | 4Tech Inc. | Cardiac tissue cinching |
EP3194017A1 (en) | 2014-09-08 | 2017-07-26 | Cardionomic, Inc. | Methods for electrical neuromodulation of the heart |
AU2015315658B2 (en) | 2014-09-08 | 2019-05-23 | CARDIONOMIC, Inc. | Catheter and electrode systems for electrical neuromodulation |
US10092742B2 (en) | 2014-09-22 | 2018-10-09 | Ekos Corporation | Catheter system |
FR3026631B1 (en) * | 2014-10-03 | 2016-12-09 | Ecole Polytech | IMPLANTABLE MEDICAL DEVICE WITH SENSORS |
EP3284412A1 (en) | 2014-12-02 | 2018-02-21 | 4Tech Inc. | Off-center tissue anchors |
EP3242717B1 (en) | 2015-01-05 | 2019-06-12 | Cardionomic, Inc. | Cardiac modulation facilitation systems |
GB2563155A (en) | 2015-02-12 | 2018-12-05 | Foundry Innovation & Res 1 Ltd | Implantable devices and related methods for heart failure monitoring |
US10874349B2 (en) | 2015-05-07 | 2020-12-29 | Vectorious Medical Technologies Ltd. | Deploying and fixating an implant across an organ wall |
EP3307388B1 (en) | 2015-06-10 | 2022-06-22 | Ekos Corporation | Ultrasound catheter |
EP3317617B1 (en) * | 2015-06-30 | 2020-06-17 | Micro Motion Inc. | Magnetic flowmeter with automatic in-situ self-cleaning |
US11039813B2 (en) | 2015-08-03 | 2021-06-22 | Foundry Innovation & Research 1, Ltd. | Devices and methods for measurement of Vena Cava dimensions, pressure and oxygen saturation |
FR3042873A1 (en) | 2015-10-23 | 2017-04-28 | Ecole Polytech | METHOD AND SYSTEM FOR DISCRIMINATING CELLS |
EP4302713A3 (en) | 2015-11-16 | 2024-03-13 | Boston Scientific Scimed, Inc. | Energy delivery devices |
US11206988B2 (en) | 2015-12-30 | 2021-12-28 | Vectorious Medical Technologies Ltd. | Power-efficient pressure-sensor implant |
EP3426338A4 (en) | 2016-03-09 | 2019-10-30 | Cardionomic, Inc. | Cardiac contractility neurostimulation systems and methods |
FR3049843A1 (en) | 2016-04-06 | 2017-10-13 | Instent | MEDICAL DEVICE PROVIDED WITH SENSORS |
US11206992B2 (en) | 2016-08-11 | 2021-12-28 | Foundry Innovation & Research 1, Ltd. | Wireless resonant circuit and variable inductance vascular monitoring implants and anchoring structures therefore |
EP3496606A1 (en) | 2016-08-11 | 2019-06-19 | Foundry Innovation & Research 1, Ltd. | Systems and methods for patient fluid management |
US11701018B2 (en) | 2016-08-11 | 2023-07-18 | Foundry Innovation & Research 1, Ltd. | Wireless resonant circuit and variable inductance vascular monitoring implants and anchoring structures therefore |
US11284840B1 (en) | 2016-08-26 | 2022-03-29 | W. L. Gore & Associates, Inc. | Calibrating passive LC sensor |
US10240994B1 (en) * | 2016-08-26 | 2019-03-26 | W. L. Gore & Associates, Inc. | Wireless cylindrical shell passive LC sensor |
CN110199358B (en) | 2016-11-21 | 2023-10-24 | 森索姆公司 | Characterization and identification of biological structures |
EP3725214A1 (en) | 2016-11-29 | 2020-10-21 | Foundry Innovation & Research 1, Ltd. | Wireless resonant circuit and variable inductance vascular implants for monitoring patient vasculature system |
US11944495B2 (en) * | 2017-05-31 | 2024-04-02 | Foundry Innovation & Research 1, Ltd. | Implantable ultrasonic vascular sensor |
US11779238B2 (en) | 2017-05-31 | 2023-10-10 | Foundry Innovation & Research 1, Ltd. | Implantable sensors for vascular monitoring |
EP3664703A4 (en) | 2017-09-13 | 2021-05-12 | Cardionomic, Inc. | Neurostimulation systems and methods for affecting cardiac contractility |
US11116561B2 (en) | 2018-01-24 | 2021-09-14 | Medtronic Ardian Luxembourg S.A.R.L. | Devices, agents, and associated methods for selective modulation of renal nerves |
US10874774B2 (en) * | 2018-02-14 | 2020-12-29 | Cook Medical Technologies Llc | Active implantable medical device and method of using an active implantable medical device |
CA3107959A1 (en) | 2018-08-13 | 2020-02-20 | CARDIONOMIC, Inc. | Systems and methods for affecting cardiac contractility and/or relaxation |
EP3840830A4 (en) * | 2018-08-25 | 2022-05-18 | ZetrOZ Systems LLC | Fleixble and wearable long duration ultrasound device |
CN109432584A (en) * | 2018-10-23 | 2019-03-08 | 广州丰得利实业公司 | Ultrasonic-intermediate Frequency drug introducing apparatus |
EP3946556A1 (en) | 2019-03-29 | 2022-02-09 | Cardiac Pacemakers, Inc. | Systems and methods for treating cardiac arrhythmias |
EP3946568A1 (en) | 2019-03-29 | 2022-02-09 | Cardiac Pacemakers, Inc. | Systems and methods for treating cardiac arrhythmias |
CA3137307A1 (en) | 2019-05-06 | 2020-11-12 | CARDIONOMIC, Inc. | Systems and methods for denoising physiological signals during electrical neuromodulation |
EP3753524B1 (en) * | 2019-06-20 | 2024-03-20 | AURA Health Technologies GmbH | Ultrasound marker, ultrasound marker system and method of operating an ultrasound marker system |
WO2021050685A1 (en) | 2019-09-11 | 2021-03-18 | Cardiac Pacemakers, Inc. | Tools and systems for implanting and/or retrieving a leadless cardiac pacing device with helix fixation |
JP2022547306A (en) | 2019-09-11 | 2022-11-11 | カーディアック ペースメイカーズ, インコーポレイテッド | Devices and systems for implanting and/or withdrawing leadless cardiac pacing devices using helical fixation |
CA3150339A1 (en) | 2019-09-12 | 2021-03-18 | Brian W. Donovan | Systems and methods for tissue modulation |
AU2020371599A1 (en) * | 2019-10-21 | 2022-06-09 | Incando Therapeutics Pte. Ltd. | Methods and apparatus for phototherapy |
US11540776B2 (en) | 2020-03-20 | 2023-01-03 | Xenter, Inc. | Catheter for imaging and measurement of pressure and other physiologic parameters |
US11759661B2 (en) | 2020-05-20 | 2023-09-19 | Brainsonix Corporation | Ultrasonic transducer treatment device |
GB2602669B (en) * | 2021-01-12 | 2023-04-12 | Hofmeir Magnetics Ltd | Pulsed electromagnetic field system |
EP4333776A1 (en) * | 2021-05-05 | 2024-03-13 | Boston Scientific Scimed Inc. | Medical device with sensing capabilities |
US11400299B1 (en) | 2021-09-14 | 2022-08-02 | Rainbow Medical Ltd. | Flexible antenna for stimulator |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4681111A (en) * | 1985-04-05 | 1987-07-21 | Siemens-Pacesetter, Inc. | Analog and digital telemetry system for an implantable device |
US4990155A (en) * | 1989-05-19 | 1991-02-05 | Wilkoff Howard M | Surgical stent method and apparatus |
US5749914A (en) * | 1989-01-06 | 1998-05-12 | Advanced Coronary Intervention | Catheter for obstructed stent |
US6053873A (en) * | 1997-01-03 | 2000-04-25 | Biosense, Inc. | Pressure-sensing stent |
Family Cites Families (34)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4020830A (en) | 1975-03-12 | 1977-05-03 | The University Of Utah | Selective chemical sensitive FET transducers |
JPS5466194A (en) | 1977-11-04 | 1979-05-28 | Kuraray Co | Fet sensor |
US4331654A (en) | 1980-06-13 | 1982-05-25 | Eli Lilly And Company | Magnetically-localizable, biodegradable lipid microspheres |
US4383529A (en) | 1980-11-03 | 1983-05-17 | Wescor, Inc. | Iontophoretic electrode device, method and gel insert |
US4416274A (en) | 1981-02-23 | 1983-11-22 | Motion Control, Inc. | Ion mobility limiting iontophoretic bioelectrode |
US4484569A (en) | 1981-03-13 | 1984-11-27 | Riverside Research Institute | Ultrasonic diagnostic and therapeutic transducer assembly and method for using |
US4411648A (en) | 1981-06-11 | 1983-10-25 | Board Of Regents, The University Of Texas System | Iontophoretic catheter device |
US4558690A (en) | 1982-01-26 | 1985-12-17 | University Of Scranton | Method of administration of chemotherapy to tumors |
US4799479A (en) * | 1984-10-24 | 1989-01-24 | The Beth Israel Hospital Association | Method and apparatus for angioplasty |
US4689986A (en) | 1985-03-13 | 1987-09-01 | The University Of Michigan | Variable frequency gas-bubble-manipulating apparatus and method |
US4652257A (en) | 1985-03-21 | 1987-03-24 | The United States Of America As Represented By The Secretary Of The Navy | Magnetically-localizable, polymerized lipid vesicles and method of disrupting same |
US4935345A (en) | 1987-04-07 | 1990-06-19 | Arizona Board Of Regents | Implantable microelectronic biochemical sensor incorporating thin film thermopile |
US5016615A (en) | 1990-02-20 | 1991-05-21 | Riverside Research Institute | Local application of medication with ultrasound |
US5078736A (en) * | 1990-05-04 | 1992-01-07 | Interventional Thermodynamics, Inc. | Method and apparatus for maintaining patency in the body passages |
US5499971A (en) * | 1990-06-15 | 1996-03-19 | Cortrak Medical, Inc. | Method for iontophoretically delivering drug adjacent to a heart |
US5178618A (en) * | 1991-01-16 | 1993-01-12 | Brigham And Womens Hospital | Method and device for recanalization of a body passageway |
US5277191A (en) | 1991-06-19 | 1994-01-11 | Abbott Laboratories | Heated catheter for monitoring cardiac output |
US5500013A (en) * | 1991-10-04 | 1996-03-19 | Scimed Life Systems, Inc. | Biodegradable drug delivery vascular stent |
WO1994006380A1 (en) * | 1992-09-16 | 1994-03-31 | Hitachi, Ltd. | Ultrasonic irradiation apparatus and processor using the same |
US5267985A (en) | 1993-02-11 | 1993-12-07 | Trancell, Inc. | Drug delivery by multiple frequency phonophoresis |
US5445608A (en) | 1993-08-16 | 1995-08-29 | James C. Chen | Method and apparatus for providing light-activated therapy |
US5487760A (en) * | 1994-03-08 | 1996-01-30 | Ats Medical, Inc. | Heart valve prosthesis incorporating electronic sensing, monitoring and/or pacing circuitry |
US5694936A (en) | 1994-09-17 | 1997-12-09 | Kabushiki Kaisha Toshiba | Ultrasonic apparatus for thermotherapy with variable frequency for suppressing cavitation |
US5490840A (en) | 1994-09-26 | 1996-02-13 | General Electric Company | Targeted thermal release of drug-polymer conjugates |
US5603731A (en) * | 1994-11-21 | 1997-02-18 | Whitney; Douglass G. | Method and apparatus for thwarting thrombosis |
US5833603A (en) * | 1996-03-13 | 1998-11-10 | Lipomatrix, Inc. | Implantable biosensing transponder |
US5749890A (en) * | 1996-12-03 | 1998-05-12 | Shaknovich; Alexander | Method and system for stent placement in ostial lesions |
US5810871A (en) * | 1997-04-29 | 1998-09-22 | Medtronic, Inc. | Stent delivery system |
US6093141A (en) * | 1997-07-17 | 2000-07-25 | Hadasit Medical Research And Development Company Ltd. | Stereotactic radiotreatment and prevention |
US5967986A (en) * | 1997-11-25 | 1999-10-19 | Vascusense, Inc. | Endoluminal implant with fluid flow sensing capability |
US6231516B1 (en) * | 1997-10-14 | 2001-05-15 | Vacusense, Inc. | Endoluminal implant with therapeutic and diagnostic capability |
US5807258A (en) * | 1997-10-14 | 1998-09-15 | Cimochowski; George E. | Ultrasonic sensors for monitoring the condition of a vascular graft |
SE514944C2 (en) * | 1997-12-30 | 2001-05-21 | Lars Sunnanvaeder | Apparatus for the therapeutic treatment of a blood vessel |
EP1043949A2 (en) * | 1997-12-31 | 2000-10-18 | Pharmasonics, Inc. | Methods and systems for the inhibition of vascular hyperplasia |
-
1998
- 1998-02-23 US US09/028,154 patent/US6231516B1/en not_active Expired - Lifetime
-
1999
- 1999-02-03 AU AU26555/99A patent/AU2655599A/en not_active Abandoned
- 1999-02-03 EP EP99906709A patent/EP1056514A4/en not_active Ceased
- 1999-02-03 WO PCT/US1999/002272 patent/WO1999042176A1/en active Application Filing
-
2000
- 2000-10-24 US US09/695,748 patent/US7427265B1/en not_active Expired - Fee Related
-
2006
- 2006-10-20 US US11/551,673 patent/US20070112344A1/en not_active Abandoned
-
2008
- 2008-09-04 US US12/204,470 patent/US20090005859A1/en not_active Abandoned
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4681111A (en) * | 1985-04-05 | 1987-07-21 | Siemens-Pacesetter, Inc. | Analog and digital telemetry system for an implantable device |
US5749914A (en) * | 1989-01-06 | 1998-05-12 | Advanced Coronary Intervention | Catheter for obstructed stent |
US4990155A (en) * | 1989-05-19 | 1991-02-05 | Wilkoff Howard M | Surgical stent method and apparatus |
US6053873A (en) * | 1997-01-03 | 2000-04-25 | Biosense, Inc. | Pressure-sensing stent |
Cited By (69)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US8147501B2 (en) * | 2003-08-11 | 2012-04-03 | Hdh Medical Ltd. | Anastomosis method |
US20090276035A1 (en) * | 2003-08-11 | 2009-11-05 | Igor Waysbeyn | Anastomosis method |
USRE47403E1 (en) * | 2004-01-27 | 2019-05-28 | Roche Diabetes Care, Inc. | Calibration of sensors or measuring systems |
US8048141B2 (en) * | 2004-12-07 | 2011-11-01 | Boston Scientific Scimed, Inc. | Medical device that signals lumen loss |
US20060122683A1 (en) * | 2004-12-07 | 2006-06-08 | Scimed Life Systems, Inc. | Medical device that signals lumen loss |
US9031792B2 (en) | 2005-08-12 | 2015-05-12 | Cardiac Pacemakers, Inc. | Method of using a lead to regulate protein expression |
US20070036771A1 (en) * | 2005-08-12 | 2007-02-15 | Cardiac Pacemakers, Inc. | Biologic device for regulation of gene expression and method therefor |
US20070036770A1 (en) * | 2005-08-12 | 2007-02-15 | Wagner Darrell O | Biologic device for regulation of gene expression and method therefor |
US20080058905A1 (en) * | 2006-09-01 | 2008-03-06 | Wagner Darrell O | Method and apparatus utilizing light as therapy for fungal infection |
US20080058881A1 (en) * | 2006-09-01 | 2008-03-06 | Cardiac Pacemakers, Inc | Method and system for treating post-mi patients |
US20080076836A1 (en) * | 2006-09-01 | 2008-03-27 | Cardiac Pacemakers, Inc | Method and apparatus for using light to enhance cell growth and survival |
US20100070019A1 (en) * | 2006-10-29 | 2010-03-18 | Aneuwrap Ltd. | extra-vascular wrapping for treating aneurysmatic aorta and methods thereof |
US20100063575A1 (en) * | 2007-03-05 | 2010-03-11 | Alon Shalev | Multi-component expandable supportive bifurcated endoluminal grafts and methods for using same |
US8317856B2 (en) | 2007-03-05 | 2012-11-27 | Endospan Ltd. | Multi-component expandable supportive bifurcated endoluminal grafts and methods for using same |
US8709068B2 (en) | 2007-03-05 | 2014-04-29 | Endospan Ltd. | Multi-component bifurcated stent-graft systems |
US20110137385A1 (en) * | 2007-05-10 | 2011-06-09 | Tamara Colette Baynham | Method and apparatus for relieving angina symptoms using light |
US20080281305A1 (en) * | 2007-05-10 | 2008-11-13 | Cardiac Pacemakers, Inc. | Method and apparatus for relieving angina symptoms using light |
US20080307668A1 (en) * | 2007-06-15 | 2008-12-18 | Sidney Watterodt | Methods and devices for drying coated stents |
US8003157B2 (en) | 2007-06-15 | 2011-08-23 | Abbott Cardiovascular Systems Inc. | System and method for coating a stent |
US8677650B2 (en) * | 2007-06-15 | 2014-03-25 | Abbott Cardiovascular Systems Inc. | Methods and devices for drying coated stents |
US8190230B2 (en) * | 2007-11-12 | 2012-05-29 | Polar Electro Oy | Electrode structure |
US20090124881A1 (en) * | 2007-11-12 | 2009-05-14 | Polar Electro Oy | Electrode Structure |
US8486131B2 (en) | 2007-12-15 | 2013-07-16 | Endospan Ltd. | Extra-vascular wrapping for treating aneurysmatic aorta in conjunction with endovascular stent-graft and methods thereof |
WO2009131612A1 (en) * | 2008-03-21 | 2009-10-29 | William Joseph Drasler | Expandable introducer sheath |
US20110160582A1 (en) * | 2008-04-29 | 2011-06-30 | Yongping Zheng | Wireless ultrasonic scanning system |
US20100171394A1 (en) * | 2008-07-06 | 2010-07-08 | Glenn Richard A | Energy harvesting for implanted medical devices |
US9283373B2 (en) * | 2008-09-17 | 2016-03-15 | Saluda Medical Pty Limited | Knitted implantable electrode assembly and active implantable medical device |
US20100070007A1 (en) * | 2008-09-17 | 2010-03-18 | National Ict Australia Limited | Knitted electrode assembly and integrated connector for an active implantable medical device |
US20150057729A1 (en) * | 2008-09-17 | 2015-02-26 | Saluda Medical Pty Limited | Knitted implantable electrode assembly and active implantable medical device |
US8897888B2 (en) * | 2008-09-17 | 2014-11-25 | Saluda Medical Pty Limited | Knitted electrode assembly and integrated connector for an active implantable medical device |
US20110301668A1 (en) * | 2008-11-21 | 2011-12-08 | Milux Holding Sa | System, method and apparatus for supplying energy to an implantable medical device |
US8862241B2 (en) * | 2008-11-21 | 2014-10-14 | Peter Forsell | System for supplying energy to an implantable medical device |
US8870938B2 (en) | 2009-06-23 | 2014-10-28 | Endospan Ltd. | Vascular prostheses for treating aneurysms |
US9918825B2 (en) | 2009-06-23 | 2018-03-20 | Endospan Ltd. | Vascular prosthesis for treating aneurysms |
US11090148B2 (en) | 2009-06-23 | 2021-08-17 | Endospan Ltd. | Vascular prosthesis for treating aneurysms |
US8979892B2 (en) | 2009-07-09 | 2015-03-17 | Endospan Ltd. | Apparatus for closure of a lumen and methods of using the same |
US8945203B2 (en) | 2009-11-30 | 2015-02-03 | Endospan Ltd. | Multi-component stent-graft system for implantation in a blood vessel with multiple branches |
US10201413B2 (en) | 2009-11-30 | 2019-02-12 | Endospan Ltd. | Multi-component stent-graft system for implantation in a blood vessel with multiple branches |
US10888413B2 (en) | 2009-11-30 | 2021-01-12 | Endospan Ltd. | Multi-component stent-graft system for implantation in a blood vessel with multiple branches |
US9101457B2 (en) | 2009-12-08 | 2015-08-11 | Endospan Ltd. | Endovascular stent-graft system with fenestrated and crossing stent-grafts |
US8956397B2 (en) | 2009-12-31 | 2015-02-17 | Endospan Ltd. | Endovascular flow direction indicator |
WO2011095979A1 (en) * | 2010-02-08 | 2011-08-11 | Endospan Ltd. | Thermal energy application for prevention and management of endoleaks in stent-grafts |
US9468517B2 (en) | 2010-02-08 | 2016-10-18 | Endospan Ltd. | Thermal energy application for prevention and management of endoleaks in stent-grafts |
US9526638B2 (en) | 2011-02-03 | 2016-12-27 | Endospan Ltd. | Implantable medical devices constructed of shape memory material |
US9855046B2 (en) | 2011-02-17 | 2018-01-02 | Endospan Ltd. | Vascular bands and delivery systems therefor |
US9486341B2 (en) | 2011-03-02 | 2016-11-08 | Endospan Ltd. | Reduced-strain extra-vascular ring for treating aortic aneurysm |
US8574287B2 (en) | 2011-06-14 | 2013-11-05 | Endospan Ltd. | Stents incorporating a plurality of strain-distribution locations |
US8951298B2 (en) | 2011-06-21 | 2015-02-10 | Endospan Ltd. | Endovascular system with circumferentially-overlapping stent-grafts |
US9254209B2 (en) | 2011-07-07 | 2016-02-09 | Endospan Ltd. | Stent fixation with reduced plastic deformation |
US9839510B2 (en) | 2011-08-28 | 2017-12-12 | Endospan Ltd. | Stent-grafts with post-deployment variable radial displacement |
US9427339B2 (en) | 2011-10-30 | 2016-08-30 | Endospan Ltd. | Triple-collar stent-graft |
US9597204B2 (en) | 2011-12-04 | 2017-03-21 | Endospan Ltd. | Branched stent-graft system |
US20130150695A1 (en) * | 2011-12-08 | 2013-06-13 | Biotronik Se & Co. Kg | Medical Implant and Medical Arrangement |
US9770350B2 (en) | 2012-05-15 | 2017-09-26 | Endospan Ltd. | Stent-graft with fixation elements that are radially confined for delivery |
US20140187960A1 (en) * | 2012-12-28 | 2014-07-03 | Volcano Corporation | Intravascular Ultrasound Imaging Apparatus, Interface, Architecture, and Method of Manufacturing |
US20170265841A1 (en) * | 2012-12-28 | 2017-09-21 | Volcano Corporation | Intravascular ultrasound imaging apparatus, interface architecture, and method of manufacturing |
US11759169B2 (en) | 2012-12-28 | 2023-09-19 | Philips Image Guided Therapy Corporation | Intravascular ultrasound imaging apparatus, interface architecture, and method of manufacturing |
US10555720B2 (en) * | 2012-12-28 | 2020-02-11 | Volcano Corporation | Intravascular ultrasound imaging apparatus, interface, architecture, and method of manufacturing |
US10575815B2 (en) * | 2012-12-28 | 2020-03-03 | Philips Image Guided Therapy Corporation | Intravascular ultrasound imaging apparatus, interface architecture, and method of manufacturing |
US10674996B2 (en) * | 2012-12-28 | 2020-06-09 | Philips Image Guided Therapy Corporation | Intravascular ultrasound imaging apparatus, interface architecture, and method of manufacturing |
US9993360B2 (en) | 2013-01-08 | 2018-06-12 | Endospan Ltd. | Minimization of stent-graft migration during implantation |
US9668892B2 (en) | 2013-03-11 | 2017-06-06 | Endospan Ltd. | Multi-component stent-graft system for aortic dissections |
US10603197B2 (en) | 2013-11-19 | 2020-03-31 | Endospan Ltd. | Stent system with radial-expansion locking |
US11419742B2 (en) | 2014-12-18 | 2022-08-23 | Endospan Ltd. | Endovascular stent-graft with fatigue-resistant lateral tube |
US10485684B2 (en) | 2014-12-18 | 2019-11-26 | Endospan Ltd. | Endovascular stent-graft with fatigue-resistant lateral tube |
US11272840B2 (en) * | 2016-05-16 | 2022-03-15 | University of Pittsburgh—of the Commonwealth System of Higher Education | Touch probe passively powered wireless stent antenna for implanted sensor powering and interrogation |
US20220151493A1 (en) * | 2016-05-16 | 2022-05-19 | University Of Pittsburgh-Of The Commonwealth System Of Higher Education | Touch probe passively powered wireless stent antenna for implanted sensor powering and interrogation |
US11865372B2 (en) | 2019-02-13 | 2024-01-09 | Alpheus Medical, Inc. | Methods of treating tumors with drugs |
WO2022032283A3 (en) * | 2020-08-07 | 2022-04-07 | Alpheus Medical, Inc. | Ultrasound arrays for enhanced sonodynamic therapy for treating cancer |
Also Published As
Publication number | Publication date |
---|---|
US20090005859A1 (en) | 2009-01-01 |
AU2655599A (en) | 1999-09-06 |
EP1056514A4 (en) | 2008-01-16 |
US7427265B1 (en) | 2008-09-23 |
US6231516B1 (en) | 2001-05-15 |
EP1056514A1 (en) | 2000-12-06 |
WO1999042176A1 (en) | 1999-08-26 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US6231516B1 (en) | Endoluminal implant with therapeutic and diagnostic capability | |
US6585763B1 (en) | Implantable therapeutic device and method | |
US5967986A (en) | Endoluminal implant with fluid flow sensing capability | |
EP1026984B1 (en) | Ultrasonic sensors for monitoring the condition of a vascular graft | |
US20210178140A1 (en) | Catheter with multiple ultrasound radiating members | |
US11534187B2 (en) | Acoustic therapy device | |
JP4011631B2 (en) | Pressure sensitive stent | |
US6398734B1 (en) | Ultrasonic sensors for monitoring the condition of flow through a cardiac valve | |
EP1811894A2 (en) | Medical devices | |
WO1998034564A1 (en) | Medical ultrasound apparatus |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: CARDIOMETRIX, INC.,WASHINGTON Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:KEILMAN, GEORGE W.;REEL/FRAME:018819/0080 Effective date: 20070126 |
|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |