METHODS AND APPARATUS FOR TREATING ANEURYSMS
Field Of The Invention The present invention relates generally to non-invasive techniques for repairing aneurysms occurring in hollow-body biological organs and vessels, for example, the aorta and iliac arteries, and arterio¬ venous fistulas. More particularly, the present invention relates to methods and apparatus for repairing aneurysms and fistulas using hardening agents that exclude the weakened tissue from a flow path.
Background Of The Invention
In recent years a number of non-invasive techniques have been developed to repair aneurysms occurring in hollow-body biological organs and vessels, for example, the aorta, using stent-graft techniques. These techniques generally seek to "re-line" the blood flow path through the organ, for example, by fixing a fabric material across the section of weakened tissue. The fabric is then held in place with one or more stents, which may be implanted, for example, using a balloon catheter. Such arrangementε are described, for example, in Parodi U.S. Patent 5,219,355 and European Application No. 0 461 791.
Such methods and apparatus are suitable for use in only a limited number of aneurysm situations, however. In particular, for such previously known methods to be effective, the portions of the organ proximal and distal to the aneurysm (i.e., the proximal neck and the distal cuff of the aneurysm) must be relatively straight to permit the stents and liner to
obtain sufficient apposition on the organ or vessel walls.
Moreover, for such previously known methods to be effective, it is important that the nondilated diameter of the aorta proximal to the aneurysm be the same (within a few millimeters) of the nondilated portion of the distal cuff. Otherwise, the stent or stents selected to fasten the ends of the liner to the proximal and distal regions of the nondilated aorta may be incapable of the range of diametral expansion needed to engage both the proximal and distal regions.
If either of the above-described conditions occur, i.e., either insufficient lengths of the proximal neck and/or distal cuff, or large diametral discrepancies between those regions, there may be leakage at either or both of the proximal and distal ends of the graft. Consequently, the aneurysm may remain subjected to flow-induced pressure, with concomitant risk of rupture. These drawbacks of previously known non-invasive stent graft techniques are described by T. Chuter et al. in Endoluminal Vascular Prostheses, Little Brown & Co. (1995) , Chapter 2 at pp. 23-33, which is incorporated herein by reference. As further described in the foregoing text, while complicated bifurcated endovascular grafts may be used in those cases where there the distal cuff is insufficiently long, use of such previously known grafts is limited to those situations where there is no aneurysm of the iliac arteries. See, for example,
Chapter 4 of the foregoing text, which is incorporated herein by reference, especially at pp. 57-59 discussing patient selection criteria. Moreover, the use of bifurcated grafts, while increasing the number of candidates for non-invasive procedures, raises additional issues of graft sizing.
In addition to the restriction of previously known methods and apparatus mostly to those cases where some nondilated length of the aorta and/or distal cuff remains, the occurrence of aneurysms in organs and vessels other than the aorta, for example, in the iliac arteries, is untreatable using previously known non¬ invasive techniques.
While certain techniques have been recently developed for defining a cavity within an aneurysm and then filling the cavity with a heat activated molding material, as described, for example, in International Application PCT/US94/09837, these techniques do not provide for continuity of the flow path during the treatment period. Techniques such as described in the foregoing International Application therefore do not appear suitable for use in vascular aneurysms or in other applications where the flow path mst remain uninterrupted.
In view of the foregoing, it would be desirable to provide non-invasive methods and apparatus suitable for repairing aneurysms that can be used in patientε having relatively short lengths of nondilated aorta above the aneurysm, with little or no distal cuff length. It further would be desirable to provide non-invasive methodε and apparatuε εuitable for repairing aneurysms having large changes in diameter in the nondilated aorta regionε proximal and diεtal to the aneurysm. It also would be desirable to provide non¬ invasive methods and apparatuε εuitable for repairing aneuryεms in hollow-body organs and vessels other than the aorta, for example, in the iliac arteries, and for repairing arterio-venous fiεtulaε. It would be yet further deεirable to provide non-invaεive methodε and apparatus suitable for
treating aneuryεmε in hollow-body organε and veεεelε εo aε to exclude the aneuryεm entirely from either the hemodynamic circuit in the vascular syεtem or other biological fluidε or materials flowing through hollow- body organs of a nonvascular nature, so as to prevent leakage flow to the weakened aneurysm tissue, and thereby reduce the risk of rupture.
Summarv Of The Invention
In view of the foregoing, it is an object of thiε invention to provide non-invaεive methodε and apparatuε εuitable for repairing aneuryεms in hollow- body organs and vesεelε defining a flow path that can be uεed in patientε having relatively εhort lengthε of nondilated organ above the aneuryεm neck, and little or no diεtal cuff length, while retaining continuity of the flow path.
It iε a further object of the present invention to provide non-invasive methods and apparatus suitable for repairing aneurysmε in hollow-body organε and veεεelε having large changeε in diameter in the nondilated organ or veεεel regionε proximal and diεtal to the aneuryεm.
It iε another object of this invention to provide non-invasive methodε and apparatus suitable for repairing aneuryεmε in hollow-body organε and vessels other the aorta, for example, in the iliac arteries, and for repairing arterio-venous fiεtulaε. The methodε and apparatuε of the preεent invention alεo find applicability in gaεtro-intestinal, reεpiratory, reproductive organ, urethral applicationε and elεewhere where iε deεirable to "reline" a hollow-body organ and veεεels.
It iε yet another object of thiε invention to provide non-invaεive methodε and apparatus suitable for treating aneurysms in hollow-body organs and vessels so
as to exclude the aneuryεm entirely from, for example, the hemodynamic circuit, εo as to prevent leakage flow to the weakened aneurysm tisεue, and thereby reduce the risk of rupture. These and other objects of the invention are accompliεhed in accordance with the principleε of the invention by providing methods and apparatus for temporarily excluding an aneurysm from a flow path, for example, the blood flow path in the vascular εystem, while maintaining continuity of the flow path. A subεtance, εuch aε a molding material or a hardening agent, iε then injected into the aneuryεm cavity. The injected εubεtance cauεeε, for example, thromboεiε of the blood located within the cavity, or solidifies in response to exposure to an aqueous solution (e.g., blood) present in the cavity or in responεe to the application of heat.
In accordance with the invention, a hollow balloon catheter εtructure or other meanε of temporarily excluding flow from the aneuryεm cavity, while providing uninterrupted flow through a main lumen, iε tranεlu inally diεpoεed within the aneuryεm εo that itε proximal and diεtal endε extend paεt the aneurysm. The balloon catheter structure iε dimenεioned to iεolate the aneuryεm cavity from the blood flow path, while permitting blood flow to pass through a lumen in the structure uninterrupted. A suitable molding material, for example, a hydrogel or polymer of a resorbable or permanent nature, a blood hardening agent, for example, fibrin or a tiεεue material, for example, collagen, iε then injected into the aneuryεm cavity, either by a catheter, laparoεcopically, or by invasive surgical meanε.
Once the molding material haε hardened, for example, either by inducing thromboεiε of blood captured within the cavity or by body-temperature
activation of the injected subεtance itεelf or other meanε for activation of the injected substance, the balloon catheter structure is deflated and removed. The hardened mass of thrombus or polymer thus formε the new lining of the organ, and relieveε the weakened tiεsue of the aneurysm from further fluid flow stress.
In accordance with alternative embodiments of the preεent invention, aneurysmε in the iliac arterieε may also be treated using a combination of hollow balloon catheter and conventional catheter which are abutted against one another to form a mold for the new inner lining of the organ. That new inner liner is again formed by introducing a molding material or hardening agent into the cavity, defined by the walls of the aneurysm, the hollow balloon catheter and the conventional balloon catheter, to produce a coherent thro bsiε or molded maεε.
In yet further alternative embodiments, a wire mesh member may be dispoεed on the exterior εurface of the hollow balloon catheter εtructure to εerve aε a framework for retaining the coherency of the thro buε formed by introduction of the hardening agent or molding material.
Further features of the invention, its nature and various advantages will be more apparent from the accompanying drawings and the following detailed description of the preferred embodiments.
Brief Description Of The Drawings
FIG. 1 is a elevation view, partly in section, of an abdominal aorta having implanted within it a previously known stent graft. FIG. 2 is an elevation sectional view illuεtrating a firεt embodiment of the methodε and apparatuε of the preεent invention.
FIG. 3 iε an elevational sectional view of a molded masε forming the relined inner εurface of an aneuryεm.
FIG. 4 iε an elevation view, partly in section, of an alternative embodiment of the apparatus of the present invention for excluding an aneurysm that extends into the right branch of the iliac artery. FIG. 5 iε a perspective view of the aneurysm excluεion/injection portion of an alternative embodiment of an apparatus constructed in accordance with the present invention.
FIG. 6 is a perspective view of an alternative embodiment of the apparatus of FIG. 5.
FIG. 7 is an elevational view of a mesh member diεpoεed on the apparatuε of FIG. 2.
FIG. 8 iε a εectional view εimilar to that of FIG. 3, εhowing the meεh member of FIG. 7 integrated with the molded mass formed within the aneurysm.
Detailed Deεcription Of The Preferred Embodimentε
The present invention provides entirely new methods and apparatus for treatment of aneurysmε occurring in hollow-body organε or veεεelε that overcome the limitationε of previously known non- invaεive methodε. In particular, the methodε and apparatuε of the preεent invention permit an aneurysm to be isolated from flow-induced streεε or other preεεure by forming a εolid maεε of thrombuε or molding material that εerveε aε a new lining for the organ or
veεεel, while relieving flow-induced εtreεεeε in the weakened tiεεue of the aneurysm. During treatment, flow path across the aneurysm remains uninterrupted.
Referring to FIG. 1, a previously known stent graft arrangement, such as described in Parodi U.S. Patent 5,219,355 and European Application No. 0 461 791, is described. As illustratively shown in FIG. 1, stent graft 10 iε diεpoεed acroεε the region of the aneuryεm 101 in aorta 100, which iε located between renal arteries 102 and iliac arterieε 103. Aneuryεm 101 includeε a proximal nondilated region of aorta 100 above the aneuryεm referred to aε "proximal neck" 104, and a diεtal region juεt above the bifurcation for iliac arterieε 103 referred to aε "diεtal cuff" 105. Stent graft 10 generally includeε a knitted graft liner 11, conεtructed for example, of Dacron®, that iε integrated with εtentε 12 and 13 at either end. Stent graft 10 is generally threaded through a femoral artery using a delivery syεtem that is per se known. Once stent graft 10 iε positioned acrosε aneuryεm 101, as determined, for example, by radiography, stentε 12 and 13 at the endε of the graft are deployed to anchor εtent graft 10 to the nondilated portionε of the aorta at proximal neck 104 and diεtal cuff 105. Aε deεcribed briefly hereinabove, and in greater detail by T. Chuter et al. in Endolu inal Vascular Prostheεeε. Little Brown & Co. (1995) , Chapter 2 at pp. 23-33, which is incorporated herein by reference, stent graft 10 is suitable for uεe only in those patientε in which the nondilated portions of proximal neck 104 and distal cuff 105 are sufficiently long to permit stentε 12 and 13 to be adequately deployed. In addition, variationε in the aorta diameter above and below the aneuryεm may exceed the capability of previously known stent grafts to properly
engage the nondilated tiεεue at both the proximal and diεtal endε of the aneuryεm.
Generally, if either of the above-deεcribed conditionε occur more invaεive εurgical techniqueε muεt be employed to treat the aneuryεm. If εtent graft 10 were to be employed where either the proximal neck waε too short (e.g. under 10 mm) or the distal cuff were too short or non-existent, proximal leakage path 106 and retrograde leakage path 107 would arise. Because flow paths 106 and 107 would continue to exert flow- induced presεure on the wallε of aneuryεm 101, riεk of rupture of aneurysm 101 and the catastrophic consequenceε attending εuch a rupture would remain unabated by stent graft 10. Referring now to FIG. 2, a first embodiment of the methodε and apparatuε of the preεent invention are deεcribed, in which like portions of aorta 100 are designated by like reference numerals. Apparatuε conεtructed in accordance with the preεent invention iε εhown disposed across aneurysm 101 comprising hollow balloon catheter structure 20 dispoεed on guidewire 30. Catheter εtructure 20 includeε interior wall 21 forming central paεεageway 22, exterior wall 23, and lumen 24 for preεεurizing cavity 25 formed by interior wall 21 and exterior wall 23. Catheter εtructure 20 may be formed of a εuitably elaεtic material, such as polyeεter, polyethylene or polyvinyl chloride, and iε delivered tranεluminally to the εite of the aneuryεm in a collapεed εtate under fluoroεcopic guidance, aε iε typical for balloon catheterε. Catheter εtructure 20 may include bandε of suitable material to provide fluoroscopic contraεt to aεεiεt in guiding the catheter εtructure to a deεired location.
Aε will of courεe be underεtood by one of skill in the art of angioplasty catheter design, catheter structure 20 alternatively may have a
mechanical εtructure formed of a tight woven metallic or polymeric structure, and thus include a mechanically expansible, rather than balloon inflated, deployed mechaniεm. When deployed in aorta 100, blood flowε freely through central paεεage 22 of catheter εtructure 20 to iliac arterieε 103, while blood-filled cavity 108 is created between the walls of the aneurysm and the exterior wall 23 of catheter structure 20. Catheter structure 20 may have a uniform outer diameter when inflated via lumen 24, or may include additional volumes of expandable material at the proximal and distal ends to form cuffε 26 and 27 aε εhown in FIG. 2. Cuffε 26 and 27 may be uεed to improve the εeal between catheter structure 20 and proximal neck 104 and distal cuff 105 of aneuryεm 101, reεpectively, so as to minimize communication between blood paεεing through central paεεage 22 and the volume captured in cavity 108. Catheter εtructure 20 may be conεtructed with exterior wall 23 of a compliant material εo aε to conform to the anatomy of the proximal neck and diεtal cuff, and a leεε compliant, but pliable material along interior wall 22, for example, by controlling the density of the material used to construct catheter structure 20 during the manufacturing proceεε.
Still referring to FIG. 2, injection device 40 includeε needle 41 that enterε cavity 108 of aneuryεm 101 either εurgically or under laparoεcopic guidance. If inεerted laparoεcopically, needle 41 may thuε be introduced to the region of aneuryεm 101 via a conventional trocar tube. In accordance with the preεent invention, injection device 40 deliverε into cavity 108 εubεtance 45, for example, a hardening agent or molding material (deεcribed below) , that εolidifieε,
or cauεeε the blood captured in cavity 108 to εolidify, into a coherent mass 110, as shown in FIG. 3.
Substance 45 may comprise a biological hardening agent, such aε fibrin, that induceε the blood captured in cavity 108 to form a coherent maεε, or it may comprise a tisεue material, such as collagen, which expands to fill the cavity. If fibrin iε employed, it may be separated out of a sample of the patient's blood prior to the procedure to treat the aneurysm, and then injected into cavity 108 to cause thrombosis. On the other hand, collagen-based productε, such aε are available from Collatec, Inc., Plainεboro, New Jersey, may be uεed either to trigger thromboεiε of the volume of blood in cavity 108, or for non-vaεcular organε or vessels, to fill cavity 108.
Alternatively, subεtance 45 may compriεe a εynthetic molding material, εuch aε a εtarch-baεed poly ethylene glycol hydrogel or a polymer, εuch aε poly- capro-lactone, that iε heat hardenable or hydrophilic. In a preferred embodiment of the invention, a εtarch- baεed poly ethylene glycol hydrogel iε uεed that εwellε when exposed to an aqueouε εolution. Hydrogelε εuitable for uεe with the preεent invention may be obtained, for example, from Gel Med, Inc. , Bedford, Maεεachuεettε. Hydrogelε or poly erε may alεo be εelected to harden, for example, upon exposure to body temperature or blood pH. In addition, catheter εtructure 20 may further include a reεiεtively heated winding diεpoεed on its outer εurface (not εhown) to activate hardening of subεtance 45.
As yet a still further alternative, εubεtance 45 may compriεe a composite of helical polyester and platinum fiber coils, such as available from Target Therapeutics, Inc., Fremont, California, that induce thromboεiε of the blood within cavity 108.
Referring εtill to FIG. 2, εubεtance 45 iε injected into cavity 108 between aneuryεm 101 and exterior wall 23 of catheter εtructure 20 εo aε to induce the blood captured in cavity 108 to form a coherent thrombotic maεε, or in the case of synthetic molding materialε, to entirely fill the cavity and form a εolid maεε. It iε expected that, depending upon the type or hardening agent or molding material uεed, εolidification of the content of cavity 108 of aneuryεm 101 may take about ten minuteε or leεε. The balloon of catheter structure 20 is then deflated, and the hollow balloon catheter structure 20 and guidewire 30 are withdrawn.
As shown in FIG. 3, the solidified mass formed in cavity 108 resulting from the addition of the hardening agent or molding material creates mass 110 having pasεageway 111. Paεεageway 111 becomeε incorporated in the blood flow path upon removal of catheter εtructure 20. To facilitate removal of catheter εtructure 20 from εolidified maεε 110, exterior wall 23 of catheter εtructure 20 may be coated with a εuitable adherent (i.e., non-εtick) coating, for example. Teflon®, a registered trademark of the E.I. duPont de Nemours Company, Wilmington, Delaware (polytetrafluorethylene) , or other suitable biocompatible material, such aε Parylene®, available from Paratech, Inc., Aliεo Viejo, California.
Referring now to FIG. 4, an alternative embodiment of the methodε and apparatuε of the present invention is described for use in situationε where one or both external iliac arterieε include aneuryεmε. In the embodiment of FIG. 4, like partε of the apparatuε are again referenced with like numberε. Thuε, apparatuε 50 of the embodiment of FIG. 4 includeε hollow balloon catheter εtructure 20, guidewire 30 and conventional balloon catheter 60 diεpoεed in the right
branch of the iliac artery and urged in abutment againεt the lower portion of catheter εtructure 20. Catheter εtructure 20 includeε an elaεtic outer membrane forming exterior wall 23 and includeε a inner wall 21 forming passageway 22. Catheter structure 20 is mounted for deployment along guidewire 30 from a collapsed εtate in which it iε delivered to the εite of the aneuryεm via a femoral artery. Unlike the hollow balloon catheter εtructure of FIG. 2, catheter structure 20 of FIG. 4 includeε tapered lower portion 26 that extendε into the left iliac artery.
Balloon catheter 60 may be of conventional balloon catheter conεtruction and iε delivered tranεluminally in a collapεed εtate into the right iliac artery via the correεponding femoral artery. In accordance with the preεent invention, balloon catheter 60 iε delivered under fluoroscopic guidance to a location at which itε proximal end abutε againεt catheter εtructure 20. So long as completion of the treatment (i.e., injection and hardening of the cavity volume) iε completed within about ten minuteε or leεε, temporary blockage of blood flow in the iliac artery containing the conventional balloon catheter iε not expected to cause any adverse effects. Injection device 40 may then be positioned laparoscopically to inject subεtance 45 into cavity 108 defined by the wallε of aneurysm 101 and the exterior walls of catheter structure 20 and balloon catheter 60. Substance 45, which again may be a hardening agent or molding material aε deεcribed hereinabove, iε then injected into cavity 108 to εolidify the blood captured in cavity 108 into a coherent maεε. Catheter εtructure 20 and balloon catheter 60 are then deflated and withdrawn, reεtoring blood flow to the iliac bifurcation via the new paεεageε created in the solidified masε 110, εimilar to maεε 110 of FIG. 3.
Alternatively, or in addition to injection device 40, catheter 65, which may be a multi-lumen catheter, may be employed aε εhown in FIG. 4. Catheter 65 iε poεitioned with itε proximal end located in cavity 108 prior to inflation of balloon catheter 60, and may be uεed to inject εubεtance 45 into cavity 108 instead of injection device 40 and needle 41. Catheter 65 may also be used to aspirate part of the volume of cavity 108, and to replace a controlled amount of the aεpirated material with an appropriate hardening agent or molding material, thereby reducing the εize of the aneurysm from its untreated condition.
If catheter 65 iε uεed in the above-deεcribed manner to aεpirate cavity 108 of aneuryεm 101 prior to εolidification of the contentε of cavity 108, the exceεε tiεεue of the εhrunken aneuryεm may then be laparoεcopically or εurgically εtapled, thuε permanently reducing the εize of the aneuryεm and relieving preεsure from the aneuryεm on adjacent organε.
Aε will of courεe be apparent to one of εkill in the art from the foregoing deεcription, catheter 65 may be uεed with equal eaεe and to produce εimilar reεultε with the embodiment of FIG. 2, either alternatively or in addition to injection device 40. With reεpect to FIGS. 5 and 6, the proximal endε of two further alternative embodimentε of the apparatuε of the preεent invention are deεcribed. Only the balloon catheter elementε of the apparatuε are illuεtrated in FIGS. 5 and 6, εince the diεtal endε of the catheterε, including the εtop-cock and guidewire arrangementε, are well-known to thoεe of εkill in the art of balloon angioplaεty and catheter deεign. Referring to FIG. 5, an alternative configuration to hollow balloon catheter εtructure 20 of FIG. 2 is described. Balloon apparatus 70 includes
rolled εheet 71 having overlapping edgeε 72, and εpiral porouε balloon 73 wrapped along the length of rolled εheet 71. Cuff mechaniεmε 74 and 75, which may be inflatable, are diεpoεed at the proximal and diεtal endε of balloon apparatus 70, and may be inflated by a non-porous lumen of spiral balloon 73 specifically connected to cuffε 74 and 75.
Aε deεcribed below, balloon apparatuε performε the functionε of not only catheter εtructure 20 of FIG. 2 (by providing a mold for εolidification of the aneurysm cavity) , but also provides the functions of injection device 40 (or catheter 65) , as deεcribed hereinabove. Rolled εheet 71 may compriεe a polyurethane material, while cuff mechanisms 74 and 75 may comprise a suitable elastic material, for example, poly vinyl chloride. Alternatively, cuff mechaniεmε 74 and 75 may employ a εuitable mechanically expansible (non-inflatable) arrangement, and appropriate means for actuating such an arrangement. In operation, balloon apparatus 70 iε tranεluminally delivered to the εite of the aneuryεm under fluoroεcopic guidance in a collapsed state. In itε collapεed εtate, rolled εheet 71 iε wound εnugly againεt the delivery catheter, and εpiral porouε balloon 73 and cuff mechaniεmε 74 and 75 are likewiεe collapsed against the rolled sheet 71. Once located in position within the aneurysm, εo that cuff mechanisms 74 and 75 are dispoεed adjacent to the proximal neck and distal cuff (or iliac bifurcation) , respectively, cuffs 74 and 75 are actuated to exclude the aneurysm from communication with central pasεage 76 within rolled εheet 71.
Aε will of courεe be underεtood, actuation of cuff mechaniεmε 74 and 75 will cauεe rolled εheet to unroll εlightly and attain a larger internal diameter, while overlapping edgeε 72 prevent blood captured in
the cavity (defined by the exterior of balloon apparatuε 70 and the wallε of the excluded aneurysm) from communicating with blood flowing through central pasεage 76. Once apparatuε 70 is diεposed acrosε the aneuryεm and cuff mechaniεmε 74 and 75 deployed, the hardening agent or molding material, aε deεcribed hereinabove, iε injected into the cavity between the aneuryεm and the outer εurface of rolled sheet 71 via spiral porouε balloon 73. When the maεε of blood or molding material haε εolidified into a coherent maεε, cuffε 74 and 75, and porouε spiral balloon 73 are deflated and withdrawn. To facilitate deflation and withdrawal of apparatus 70 from the solidified mass formed in the aneurysm, the outer surfaceε of apparatuε 70 may be coated with Teflon® or other suitable biologically compatible non-stick material.
Referring now to FIG. 6, a further alternative embodiment of balloon apparatus 70 of FIG. 5 iε deεcribed. Balloon apparatuε 80 compriεeε a hollow balloon catheter εtructure aε deεcribed with reεpect to FIG. 2 on which a εpiral porouε balloon iε mounted, aε for the embodiment of FIG. 5. In particular, balloon apparatuε 80 includeε interior paεεage 81, preεεurizing lumen 82 and inflatable exterior surface 83 (which may have a uniform outer diameter or include proximal and distal cuffs 84 and 85) , and εpiral porous balloon 86 through which the hardening agent or molding material is injected into the excluded aneurysm.
Operation of balloon apparatus of FIG. 6 iε εimilar to that described above with respect to the embodiment of FIG. 5. Specifically, balloon apparatus 80 iε firεt delivered tranεluminally to the εite of the aneuryεm under fluoroεcopic guidance in a collapsed state. Balloon apparatus 80 is then presεurized via
lumen 82 to exclude the aneuryεm from the blood flow path while permitting continued flow through paεεage 81. A εuitable hardening agent or molding material iε then introduced into the cavity in the aneuryεm via porouε εpiral balloon. Once the maεε in the aneuryεm iε solidified, balloon apparatus 80 is then deflated and withdrawn, again leaving a "relined" aneurysm pasεage εimilar to that εhown in FIG. 3.
With reεpect to FIGS. 7 and 8, an exemplary configuration of meεh 90 for use with the catheter structure of FIG. 2 is described. Mesh 90 compriseε a thin wire or polymeric net or mesh disposed around the exterior wall 23 of hollow balloon catheter εtructure 20. Mesh 90 is placed around catheter εtructure 20 prior to delivery of catheter εtructure 20 tranεluminally to the aneurysm site, and may be εelf- expanding or expanded by inflation of catheter εtructure 20.
When the molding material or hardening agent iε introduced into cavity 108 of aneurysm 101, mesh 90 becomes incorporated into the solidifying masε 110 (εee FIG. 8) , and iε expected to reduce embolization of the molding material or hardening agent, and thuε reduce the risk of thrombosis downstream from masε 110. Upon completion of the hardening of the volume of cavity
108, hollow balloon catheter εtructure 20 iε deflated, and meεh 90 iε left in poεition within the aneurysm, where it formε part of the relined paεεage of the aorta. It will of courεe be underεtood by thoεe εkilled in the relevant artε that the exemplary embodimentε of the invention deεcribed hereinabove in no way limit the intended uεe of the methodε and apparatuε of the present invention, and that the methods of the present invention could be implemented using catheter structureε having other configurationε.
In addition, while the methodε and apparatuε of the preεent invention have been described with reference to excluding aneurysmε occurring in the abdominal aorta, the methodε and apparatuε of the preεent invention are equally applicable to gaεtro- inteεtinal, respiratory, reproductive organ, urethral applications and elεewhere where is deεirable to "reline" a hollow-body organ or veεsel.
Thus, for example, the methods and apparatuε of the preεent invention may be uεed to treat arterio- venouε fiεtulaε in a manner similar to that described above for the aorta. Application of the preεent invention in εuch treatment iε conεiεtent with the uεe of previouεly-known εtent-graft techniqueε in treatment of εuch fiεtulas, as described, for example, in the above-mentioned T. Chuter et al. text, Endoluminal Vascular Prostheεeε. at Chapter 10 at pp. 217-235, which is incorporated herein by reference. The methods and apparatus of the preεent invention are expected to provide even greater flexibility in the treatment of εuch abnormalitieε.
While preferred illuεtrative embodimentε of the present invention are described above, it will be obvious to one skilled in the art that various changes and modifications may be made therein without departing from the invention and it is intended in the appended claims to cover all such changeε and modificationε which fall within the true εpirit and εcope of the invention.