CA2110276C - Retractable-wire catheter device and method - Google Patents

Abstract

2110276 9221400 PCTABS00017 Apparatus and method for placing a vaso-occlusion wire at a selected site in a vessel. The apparatus includes a catheter (12), and a pusher-and-wire assembly (22) in which a vaso-occlusion wire (20) is held in an axially clamped position until the wire (20) has been advanced beyond the end of the catheter (12). The assembly may be adapted for guiding the catheter to the site, either by flow-directed or wire-directed movement.

Description

WO92~214~0 PCT/US92i~U~1 , 2il~7S

RETRACTABLE-WIRE CATHETER DEVICE AND METHOD

l. Field of the Invention The present invQntion relates to ~ retractable-coil catheter devic~, a pusher-and-coil assembly, a : va~o-occ}usion coil, and to a method for placing a - vaso-occIusion coil at a sele~ted site in a vessel.
,. . . . -2. BackqE~und_of the Invention 15Vaso-occlusion wires are used in treating vascular conditions i~ which it i~ desired to occlude a region '^of:a vessel~or an~-aneurysm protruding fr~m-~ vessel.
~ r~ The wire ~introduced by firs~po~sitioningf~a catheter ~~ ~t~ at the selected'~ite to be o~cluded, then advancing the - 20 wire throu~h the^catheter and ~nto the site. The wire - -- itself:is typically a soft wire coil whic~ can assume ~ i a linear- ~ondition for advancement~-through the cathe--- ~` ` ter, ànd~rassuma a convoluted configuration designed to - ~fill" the`vessel cr ~neurys~ into which the coil is 25 : introduced, as described ~or example in U.5. Patent No.
4,g94,069-Commonly, the vaso-occlusion wire must be placed SUBSTI~ SH~ET

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at a remote, small-vessel site which ean be accessed only through a tortuous vessel path involving multiple vessel branches, sharp turns at a vessel branch point, and/or small-diameter vessels, e.g., less than 2-5 mm.
S Such sites can be accessed only with a flexible, ~mall-diameter catheter, e.g., a polyethylene~tube cath?ter ha~ing a distal-end inner diameter of 10-30 mils. Such a catheter is typically ?~uided through a tortuous ~es-sel by a guidewire having a bent tip whose direction can be controlled, to steer the catheter along a selec-ted path.
After the catheter has been placed at the intended site, the guidewire is r?~moved and the catheter is loaded with a vaso-occlusion wire, which i8 then advanced through the catheter with a push?2r. When the wire is ad~anced beyond the end of cathQter at the vaso-occlusion site, it assume~ its convoluted shape de?igned to fill the vessel space into which it is placed.
O~e lLmitation of the above vaso-occlusion method - just de?cribed -~is the-~difficulty in controlling the ?osientation and~position of-the wire in the~vessel, or aneurysm?~ aft,?~r it is ejected~-from~;the catheter. For example, ~he wire ~ay fail to ~nchor itself firmly in - 25 the vassel, and ~hus be earried by blood flow to a site downstream~ of . thej.intended ~aso-occlusion sik~. In - - addition, the wire may i~properly orient itself at the - site, producing incomplete vaso-occ~usion.- In either ~ case, the vaso-occlu5ion procedure may be only partial-ly effective.

3. Summarv of thel nvention SUBSTITUTE SHEET

WO92/21400~ PCT/US92/0~6~

It is a general object of the present invention to provide.an improv~d method and catheter apparatus for placing a vaso-occlusion coil at a selected vessel site.
5Th~ invention includes, in one aspect,- catheter apparatus having a catheter d~signed for placement at a ~elected vessel site, a vaso-occlusion wire which is ext~ndable from a relaxed condition capable o~ as~uming a convoluted shape, to an extended, linear condition in which the wire can be advanced through said lumen, and a pusher designed for advancing the wire through the catheter. Confronting ends of the pusher and wire are provided with clamping structure for holding the wire in clamped engagement with the pusher, as the wire is : 15 . advanced through.the,catheter lumen.- ~he cla~ped con--dition of .the~structure i~ released when a ~elected portion of the wire has been advanced beyond the aistal catheter end, to release the wire into the v~ssel site.
In one embodiment, the clamping ~tructure includes an radial,enl~rgement carried on the wire, and expand-~ble jaws as50ciated with pusherj ~or movement between ,. a closed condition produced by contact~o~ the ~aws with the catheter~lumen,~i.in.,which the jaws are effective to ,. hold the radial e~largement in clamped engagement, zn~
. . 25 an open condition produced by expansion of the jaws, to .,release~he radial enlargement in-the wire~
, ,'"!,''' The'catheter apparatus may be designed for flow-- .directed or wire-directed catheter guidance to the site. For flow-directed guidance, the wire additional-ly includes a distal-end segment which is expandable, when advanced beyond the distal end of the catheter, to enhance movement of the segment in the direction of SVB~T~ T

WO92/21~ PCT/US92 ~

211~27S

highest fluid flow. For wire-directed guidance, the wire additionally includes a distal-end segment which assumes a bent configuration when the end region is advanced beyond the distal end of the catheter. The S clamping structure in this embodiment is effective to transmit torque between the pusher and the wire, for orienting the bent wire tip during catheter placement.
In another. aspect, the invention includes a pusher-and-wire assembly for use with a catheter which can be placed at a selected vessel site. The assembly includes a vaso-occlusion wire extendable from a re-laxed condition capable of assuming a convoluted con-dition, to an extended, linear condition in which the .. -wire can be advanced through the lumen of the catheter, -.- 15- .and a pusher which is operable from the proximal cathe-ter end to advance ~he wire axially, with such in its extended condition, through the catheter by contact between confronting ends of the pusher and wire. Also - included in the invention is a vaso-occlusion wire device for use with a catheter and pusher of the types described above..
~ ; ln.another aspect, the invention includes a method r.~ for placing a vaso-occlusion wire at-a selected site in r ~ ~ a ves~el.. The method includes the steps of guiding the .- 25 distal.-.;end of ~ catheter to SUGh site, advancing through the catheter,~ and a~vaso-occlusion wire which is~-extendable.from a-relaxed condition capable to ~: assuming a convoluted condition, to an extended, linear -. condition. During wire advancing, the wire is main-tained in an axially clamped condition in which the coil can be moved axially in both directions within the catheter, until a selected portion of the wire has been SUBSTITUTE SHEET

WO92/~1400~ PCT/US92~ ~1 21i~27~

ad~anced beyond the distal end of the catheter, at which point the wire is released from its clamped condition.
The ~ethod may be adapted for use in guiding the catheter to the selected vaso-occlusion site through a branched vessel path by flow-directed or wire-directed movement of the catheter's distal end, employing one of the modified wires described above.
These and other objects and features of the invention will become more fully apparent when the following detailed description of the invention is read in conjunction with the accompanying drawings.

~; Brief Desçription of the ~rawina . ~Figure 1 shows a catheter apparatus conctructed according to a general embodiment of the invention;
Figure 2 is an enlarged, fragmentary view of a wire-and-puæher assembly taken gen rally along line 2-2 in Figure l;
Figure 3 is an~enlarged, fragmentary view of a second embodiment of..-a-wire-and-push~r asse~bly in the invention; ~.r~c-~
Figure 4 illustrates one mechanism of wire release i~ the apparatu8 of th~.~nvention;
Figure S illustrates- a second mechani~m of wire . release in another~embodiment of the inventio~;
Figure. 6- illustrates another embodiment of a ~pusher-and-wire a5semb1y in the invention;
- Figure 7 illustrates the mechanism of wire release in the ~igure-6 assembly;
Figures 8A and 8B illustrate the method of wire placement in a vessel, in accordance with the method of SUBSTI ~ IJTE SH~T

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the invention;
FigurDs 9A-9D illustrate steps in a method of wire retrieYal or repositioning, in accordance with a ~urther aspect of the method of the invention;
Figures lOA and lOB illustrate a vaso-occlusive wire constructed, according to another embodi~ent of ~he invention, for use in ~low-directed catheter placement, at retracted (lOA~ and extended (lOB) positions in a catheter;
~igure 11 illustrates the method of flow-directed guidance employing the Fi~ure-10 wire;
Figures 12A and 12B illustrate a vaso-occlusive wire constructed, according to another embodiment of the invention, for use in wire-directed c theter placement, at retracted (12A~ and extended (12B) -- - positionC in a cathster;
Figure 13 shows ~odified clamping structures for use in the wire construction shown in Figure 12;
Figure 14 is a cross-sectional view taken along line 14-14 in Figure 13; and : -~ Figure 15 illustrates *he method o wire-directed guidance employing the Figu~e-12 wire.~

De~ailed Des~rietion of ~he Invention .- 25 A.s Catheter A~ar~tus ; Figure:1 shows alvaso-occlusion catheter de~ice, or apparatUs 10 con~tructed according to the present invention. The device ~enerally includes a ~atheter 12 formed of an elongate tubular member 14 having proximal and distal ends 15, 15, respectively. The tubular mem-~2r is preferably between about 50-300 cm in length, typically be~ween a~out 100-200 cm in length. An inner SUBSTITUl-E SHEET

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lumen 18 (Figures 2 and 3) extends between the two ends.
The catheter is designed conventionzlly for accessing a ves~el site at which vaso occlusion is desired. Typically, the ~essel site is within a small-diameter vessel having 2-5 mm lumen diameter, and is accessible by way of a tortuous vessel path which may involve sh~rp vessel turns and multiple vessel branches. For accessing such vessel sites, the cathe-ter preferably has a small-diameter, flaxible-tube construction, with a lumen diameter of less than about mil, and preferably between about 12-30 mil.
Catheters of this type are commercially a~ail~ble, for example, for accessing deep brain vascular sites.
- 15Although- not ~hown in Figure 1, the catheter :` device~may include:a guidewire useable with the cathe~
ter to guide the distal catheter end toward the intend-ed vaso-occlusion site. Guidewires of this type are .c~mmercially available, ~nd generally include ~n elon-.- 20 gate wire having a tapered, wire-wound distal end region^-which~is-adapted;-~to be-threaded through a tor-tùous vessel path,~?wi^t~ the~'catheter being mo~ed axi-.r' -al-Iy;along the advanced~guidewlrei Once the catheter has~been guided to the selected vaso-occlusion site, ~; 25:~ the guidewire^ca~ ~e-r~moved~from ~he ~atheter.-~-?~Aleo^~included-in:the app~ratus is a vaso-occlusion r,.~wire 20 which~ ~extendable from a ralaxed, convoluted condition shown, for èxample, in Figures 8A and 8B, to an extended, linear condition, shown in Figure ~, in which the wire can be adYanced axially through the catheter lumen. The wire is moved through the catheter by a pusher 22 in the apparatus which is operable from SUBSTI~V ~ ~ SH~ET

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the proximal end of the catheter. The construction of the wire and pusher are detailed below.
According to one feature of the invention, the wire and pusher are held together in clamped engagement at their confronting ends in the catheter by clamping structure or means 24 associated with the wire and pusher, as will be detailed below. The clamping en-gagement of the wire and push~r are designed to be released, in accordance with the invention, by catheter struct~re or means adjacent the catheter's distal end.
The clamping and release structure are also detailed below.
Figure 2 is an enlarged view of the catheter ap-paratus, taken generally along tha region 2-2 in Figure 1, and sh~wing detail~ of clamping ~tructure 24 associ-- ated wi~h confronting ends 26, 28, of .pusher 22 and wire 20, respecti~ely. The clamping structure in the Figure-2 ~mbodi~ent includes a jaw-like clamp 30 form-ing the distal end portion of the pusher, and a radial enlargement 32 forming the proximal end portion of the - ~wire. ~The-clamp has.a;pair;:of opposed~jaws 34, 36 - ~ which.~areSexpandable i~etween a clo~ed condition pro-duced by contact of the jaws with the catheter lumen, as ~hown in Figure 2,... and~ an open condition in whlch the ~aw~ are in a relaxed, somewhat expa~ded condition, - shown in Figure~4.,~The radial enlargement in the wire - is dimensioned for positive-clamping by the jaws, wit~
- such in their closed condition-~Figu~e 2) and for - release from the jaws, in an axial ~irection, with the jaws in their open condition tFigure 4).
In one general em~odiment, the extendable portion of wire Z0 takes the form of a coil, such a~ indicated SUBSTITUTE SHEET

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211~276 at 38 in Figures 2 and 4, formed by wrappings or wind-ings of a fine wire thread 40, prefera~ly 0.002 mils to 0.006 mil~ platinum, tungsten, or gold thread which is available, for example, fr~m California Fine Wire Com-pany (Grover City, Calif.). The windings ar~ prefera-bly made by wrapping the thread on a ~pinning mandrel, according to known wire-manufacturing methods. The wire advance on a mandrel is adjusted to produce a single layer wire with a minimum helical pitch, i.e., in which the windings are close packed. Typically, the mandrel has a diameter of between 5-Z5 mils (1/1000 inch), yielding a wire whose outer diameter is between a~out 10-30 mil~. The soft, flexible wire produced on the mandrel is cut to desired lengths after removal --~S,- from the mandrel. For wires intended for use in ves-. sels with diameters of about 2 ~m and smaller, the wirehas a preferred langth o~ about 3-6 cm. For vessels in the 2 6 mm range, wire lengths of b2tween about 5-10 cm - are preferred.
... 20 In the embodiment ~h~wn,.:the wire as~ume~ a convo-luted:~hape in its relaxed~tate. The relaxed, convo--:`f.~ luted shape ! of the ,r, coili~ -a~hie~ed:by shaping the ~ wire,- i~e~, by wrapping the-wire about a larger-diame-'`'.f''' 1 ^'': ter: ~andrel to form a.helical shape, e,g., having a 7 25 i. helical diameter between 2-6 mm, re~pectively.. The j","~ w~re ~ay be further deformed-to contain irregularities in the helical winding, guch-that the: wire adopts a ~ -- folded,-convoluted conformation in a relaxed condition, -- - as illustrated in FI~ 6B. Th~ irregularities are pre-ferably made by de$orming, as ~y twisting, the wire in~he region of desired bends with the wire on the heli-cal winding mandrel.

SUBSTITUTE SHEET

WO92/21400- PCT/US92~

2110~'7~

- ' - After shaping, the coil is treated at about 800F
for 24 hours for memory retention after it is shaped.
The memory in the coil is effective to return the wire from a stretched, linear condition in which it is advanced through a catheter to a randomly oriented, spaced-filling relaxed condition as the wire i8 re-leased from the catheter. The high memory in the wire is achieved, in part, by the overall length of the thread used in forming the coil, i.e., the high ratio of thread length change in wire shape. In an alterna-tive embodiment, the coil is not preformed in a convo-luted shape, but is sufficiently flexible to assume ~uch a convoluted state as it is forced into a vessel at the..vaso-occ~usion ~ite.
- 15 . Alternati~ely, the extendable portio~ of the vaso-occlusion wire may be formed from a flexible, preshaped polymer tube or rod. The convoluted shape of the wire may be ~chieved by a combination of a helical winding and/or irregularities which are imparted during heat ~reatment, or.by shaping the wire as it is extrudP.d, . : . before..~cooling, or.:by injection molding. Suitable polymer~.for~nse~-in preparing thisltype of~wire include . any biocompatible poly~er such as polyethylene, poly-urethane,.~polypropylene, and the li~e, which are cap-able (by their inherent memory) of substantially rever-.; siblel-.shape-retention between extended and preformed, - ~- relaxed conditions. ~- .
- ~ .With cont~nued reference to Figure 2, ~he proximal - end of the-wire (the end confronting the pusher in the catheter) includes a stem 42 which connects the coiled portion of the wire to radial enlargement 32. The stem and radial enlargement may be fo~med b~ extrusion or SUBST~TlJTE SHEET

.: ., } ~

~WO92/21400~ PCTiUS92/04~1 2110~7~

molding a ~uitable biocompatible polymer material. The stem is attached to the coil by an adhesi~e or solder.
Alternatively, where the extendable portion of the wire is formed of a polymer tube or rod, the stem and radial enlargement can be formed as a single extruded piece.
Pusher 22 shown in Figure 2 is formed of a conven-tional guidewire 44 which is designed for axial move-ment within the catheter, by manipulation of the guide-wire's proximal end at the proximal end of the cathe-ter. The guidewire has a typical diameter of betweenabout 8-18 mils, for use with a catheter having a lumen diameter of between about 15-30 mils, respectively.
Although not shown here, the guidewire may have a more - ~ flexible distal end'region formed of a reduced diameter ' ' 15 --: taper in the distal region of'the guidewire, and this tapered region may be-~r`einforced, for`greater column strength, by a wire wrapping,' according to known guidewire construction.
The clamp in the pusher wire may be formed from a 20 - metal or polymeric rod having suitable shape-retention and resilienc~lproperti'es'.''';"~Po}ymer rods suitable for ~s~ forming the~'clamp~iinclùdé p`olyethylene, Teflon~, ~F~ polypropylenè, and`'polyurethane`'.~-The rod typically has a diameter approximately that of'~he guidewire, e.g.~, '- 25 ~;-between 8-18, and a`-le`ngth between a~out 0.5-2 cm. To ;~ ;}~form the clamp,- the rod''î~ cùt;axially through a center '-'''~`' ''^';:'~ ~plane along a major portion;`of't~ë~`rod length. This ~ 'cut forms two'hemicylindricaI rod sections which will - form the jaws of th'e clamp.~- These jaws are formed by shaping the rod sect~ons about a shaping member having a cross-sectional shape similar to that of the region between the jaws in Figure 4. Shaping of the rod sec-SVBSTI ~ UTE SH~T

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tions over the shaping member may be accomplished by forcing the rod sections over the shaping member, in the case of metal jaw members, or by heat-shaping the rod sections over the shaping member, in the case of a heat-shapable polymer material. The shaping is prefer ably carried out to form the jaws in their open posi-tions, such as illustrated in Figure 4, requiring a . slight compressive force on the jaws to place the clamp in its closed condition. The clamp is attached to the distal end of the guidewire by a solder or adhesive attachment 45, to form the pusher~
It will be appreciated that the clamp may have three of more jaws which are movable toward and away from the axis of-the clamp, between a relaxed, open - lS condition, and a .-compressed cla~ping condition. A
multi-jaw clamp of thi~ type can be formed as above, where a suitable rod i8 cut axially into three of more rod sections, and the ~ections are shaped to form the jaws of the clamp. A multi-jaw clamp has an advantage 20 . over the two-jaw-clamp shown in Figures 2 and 4, in -. . .that the stem.-carrying-the radial enlar~ement in the rl wire ~ positively~-oriented în. an axial direction - . durin~axial movement~of. the wire through and b~yond the distal end of the wire.
. ~ ~ The pusher and wire described above with reference ..... ~ to Figures 1~? and.2~.. form, collectively, a pusher-and-- wire ass~mbly ~46 which forms another aspect of the invention. The assembly is designed ~or use with a . catheter, such as catheter 12, in placing a vaso-occlusion wire at a selected vascular site, and at aselected configuration at the site.
~igure 3 illustrates a clamping structure S0 simi-SU~STITUTE SHEET

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lar to structure 24 shown in Figure 2, but in which aclamp 52 forms the proximal end of a vaso-occlusive wire 54, and a radial enlargement S6 captured in the clamp is formed at the distal end of a pusher 58. The clamp may be formed as de~crib~d above, for attachment to one end of a coil. As shown the radial enlargement is preferably formed at the end of a rod ~egment 60 having a reduced-diameter stem 62 and a base 64 at-tached, at a solder or adhesive atta.hment 65, to the distal end of a guidewire 66. The clamp structure shown in Figure 3 functions substantially identically to the structure shown in Figure 2, as will be seen.
The pusher and wire in this embodiment form a pusher--- . and-wire assembly 68 for.use with a catheter, such as :-.. 15 -,catheter 67, for placement of a vaso-occiusion wire at ~ .a~salected vascular site. . ! ~ `` - .
- Figure 4 illustrates the distal end region of ca-theter 12 shown in Figures 1, and 2, illustrating the clamping structure in the apparatus in a release condi-20 ~. tion. In this embodiment, clamp.30 is..retained in its clamped condition by.contact with the.inner lumen of ca ~ eter 12,~and allowed;to expand to-its-open, release condition when~the pusher:.is moved:axially to a posi-tion in which ~ e clamp jaws are ~ust beyond the distal `. -25..;. catheter end. As seen and des~ribed above, jaw~ 34, 36 .s~-,r~ in`the.clamp are spread sufficiently in the open clamp .condition to allow radial enlar~ement.32 to escape, in -a~axial direction, from the.clamp, thus releasing the - . .- .wire from the pusher.
In this embodiment, the distal end of the catheter acts as means for releasing the clamped engagement of the of the wire to the pusher, as the clamp has been SIJBSTITUT' SH~ET

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advanced beyond the dictal catheter end. The ca~heter distal end plays a ~imilar role in releasing the clamped engagement of wire and pusher in the Figure-3 2mbodiment, when the clamp associated with the wire is S advanced beyond the distal end of the cathe~er.
Figure S illustrates clamp release means i~ a ca-theter apparatus 70 like that described above, but hav-ing a catheter 72 whose distal end region contains a radially enlarged segment 74. The greater lumen wall diameter in segment 74 is designed to allow expansion of jaws 76, 78 in a pusher clamp 80, as indicated, to allow axial release of ~ radial enlargement 82 forming one end of a wire 84, for wire release. The pusher and wire are constructed as described above with respect to Figure 2.. In this embodiment, the enlarged catheter segment ~erves as ~he release means in the apparat~s for releasing the clamped engagement of the pusher to the wire. It is noted that the clamping structure shown in Figure 3 would not be suitable for use in the Figure 5 pre~en~ release means, since the wire in the -- ~ Figure-3 embodiment~would be released from the pusher, : - f ~ bu~not~from the~catheter-by positioning the clamp in - : the enlarged catheter segme~t. -t F~gures 6 and 7 illustrat~ a se~ond general type :- 25 o~-clamp struc~ure-for clamping ~ vaso-occlusive wire - axially to the confronti~g end of pusher in a catheter.
- The figures show ~he distal end region of a pusher 86 - and the confronting, proximal end of a vaso-occlusive wire 88 which i~ clamped to the pusher.i The pusher in thi~ embodiment has a coiled-loop clamp 89 formed by a helically looped segment 90. The loop is constructed to assume, in a relaxed condition, the expanded loop SUBSI ITUTE SHEET

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configuration shown in Figure 7 in which the center region 92 of the segment loop is large enough to allow axial escape of a radial enlargement 94 forming the confronting end of wire 88. When the loop i disposed within a catheter, such as the on~ indicated at 93, its more tightly coiled configuration serves to capture the wire's radial enlargement as shown in Figure 6.
Wire 88 in the just-described clamping structure may have substantially the same construction as de-scribed for wire 20 in apparatus lO. Pusher 86 isformed by joining segment 90 to a standard guidewire 96, at a solder adhesive attachment 97. The segment may be formed from a polymer rod who~e coiled region is - :. reduced ~n diameter and shapad by heating, or which is formed by extrusion with a reduced-diameter end~region and shaped in the desired helical loop under heated - conditionsO The pusher and wire ~orm a pusher and-wire ass ~ ly 99.
- Although not shown he~e, the clamping structure 20 shown in Figures 6 and 7 can be modified æo that the -c~ coiled-loop;.clamp is ~carried on the vaso-occlusive ~ wirs, and~-the radial~ enlargement i ~ carried on the - :- .. pu~her,~nalogous to the~confiyurationv~hown in Figure -- . 3. In thi8 embodiment, ~ e wire may be formPd from a - 25 polymer~rod or tube, with the e~tendable portion of the .r~ wire~having the desired-convolutions~in-the ~elaxed tate,-and a proximal end segment of the wire having a ~- -.- coiled loop which is expandable be~ween a reduced-- - diameter, clamping condition, within the catheter, and a relaxed, release condition outside the lumen of the catheter.

SUBS~ T- S~-~T

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2.ll~7b In either configuration, the distal end 95 of catheter 93 provides means for releasing the clamped engagement of the of the wire to the pusher, as the clamp is advanced beyond the distal catheter end.
B. Wire-Placement Method The operation of the apparatus, for use in placing a vaso-occlusion wir~ at a æelected sit~ in the vascu-lar system, will be described with reference to Figures 8 and 9. In a typical operation, the vaso-occlusion site is accessible by a tortuous, small-vessel path which may include multiple vessel turns or bends, and one or more vessel branches. The catheter is guided to .. .. such a site, conventionally, by the use of a catheter .- 15 and guidewire, where.the guidewire i~ used for steering - - - --- along the path, and the cathetex is periodically ad-~anced along the guidewire~ The vaso-occlusion site may be an aneurysm which is to be blocked, or a r~gion in a small vessel whi~h it is desired to occlude.
.. 20. after the cathetes has been guided to the selected site, and the guidewire removed,.the-extended vaso-- -occlusion wir~and.pushe~are inserted into-the pxoxi-. mal end of.~-the cathetes,~with the-wire~clamped to the -- pusher's clamping structure~-. In;th~ embodiment shown .~.. 25 :.in Figure 2,~the extended wire is fir~t inserted into . f ~i .the.catheter with only.the radial~enlargement at the .. -- wire's-`proximal.end-~5howing. -~he pusher- clamp is placed over the enlargement and the clamp and enlarge-ment are then pushed into the catheter, compressing the clamp jaws to their clamping condition. The pusher is now advanced axially along the catheter, pushing the SUBSTITUTE SHEET

~WO92/21 ~ .q PCT/llS92/~ ~1 211~276 extending vaso-occlusion wire toward the selected vascular site.
Figures 8A and 8B show the distal end of a ca~he-ter 100 placed adjacent a selected occlusion site 102 within a small-diameter vessel 104. Figuré 8A shows the configuration of a wire 106 as it is advanced out of the catheter into the vessel, illustrat~g the convoluted, relaxed state which the wire assumes as it is released from the catheter. When the extended portion of the wire has been released, but before the wire is unclamped from the pusher, the user can view the position and confi~ ration of the wire in the vessel, e.g., by angiography. If wire placeme~t is not correct,~or the wire has not assu~ed a desired space filling configuration, the user- can ad~u~t the wire ~ position-by movement~of the catheter-in one direction -~ or another. --~
When the desired position and orientation of ~he- wire have been achieved, the user n~w advances a pusher -108--slightly-to a clamp-release position,.to release .f i~ ~the~Wire~Jfrom the catheter~and pusher- cla~p 110, as illustrated~inrFigure 8B..The~cathete~and:pusher can now be ~retracted: from~the~ ite,-~leaving the vaso-~ occlùsion wire in place~ ~:
:- 25 ~ c~ Figures 9A-9D illustrate howithe-app~ratus illus-~rated in Figures 8A~and 8B can be used!to:adjust the - -^ -position ior orientatio~ ~of va~o-occlusio~ wire 106, ~: after deposition of-wire at a vaso-occlusion site 114 - - in a ve~sel 116, or to retrieve a wire from a vessel site. In Figure 9A, the wire is shown in a relaxed convoluted configuration, but where the lower portion of the vessel is substantially unblocked by the wire, SUBSTITVT~- S~

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with the wire wedged between opposite ~ide walls of the vessel~ As a first step in the operation, the catheter and pusher, with the jaws in an open condition, are advanced to place the jaws over a section of the wire, as indicated in Figure 9B.
In ~he second ~tep, the pu~her is retracted into the catheter, to close the jaws of the clamp, and th-ereby clamp a portion of the wire to the pusher. The catheter and pusher can now be moved as a unit, either to adjust the position and orientation of th~ wire, as shown in Figure 9C, or to retract the wire from the site. Finally, when a selected coil position and orientation are achieved, the pusher is advanced to an . open-clamp position, releasing the wire from the 15.: catheter, illustrated in Figure 9D~
-;'1'~ ` : Although the operation of ~he apparatus, in a wire-placement procedurs! has been described with respect to the apparatus described with respect to Figures 1, 2, and 4, it will be appreciated how the ;~:20 ~.~procedure can be carried out in a similar fashion by ,7alternative embodi~ents of the apparatus,-such as those u~.illustrated in~Figures ~ and-5-7..- -~--- ~, c C.- Catheter~Guida~ce Wir.e-and Method ~
In the procedure outlined in Section B, the 25~ catheter w~s first placed at a selected vaso-occlusion ,çsite .by use;~.of.~.a~guidewire to guide the catheter d.'''-' through~a tor~uous -vessel path to the æite. In the '~ ' '- ,.r' '. embodiments of the in~ention described in this section, -~ the vaso-occlusion wire is itself adapted for use in guiding the catheter to the selected site. As will be seen, this approach is made possible by the ability to advance the extended vaso-occlusion wire both distally SUBSTITUTE SHEET

WO92/21400~- PCT/~S92/~U~l ~

2~10,'~76 and proximally within the catheter, by means of the clamping structure in the apparatus, described above.
The ad~antage of the approach is that the steps of first positioning the catheter with a guidewire, then removing the guidewire, and replacing the guidewire with a pusher-and-wire assembly are combined into a single step.
The embodiment of the invention i~lustrated in Figures 10 and 11 is intended for catheter guidance by flow-directed movement of a catheter in the direction of highest fluid flow. Figures lOA and lOB show a distal end region of a catheter apparatus 120 designed for such flow directed movement through and within a ve~sel 122. The apparatus includes a cathater 124, a pusher 126, and a vaso-occlusion wire 128. .~he pusher - - and wire are sacured in a clamped condition-in ~he wire by clamping structure 128 such as de~cribed above with re~pect to Figure 2. Apparatus 120 differ~ from that ~hown in Figures 1 and 2 only in the construction of wire 128,~.a~.follow~
r~ Wi~re 128~ri~ ~formed of:a coil~winding 129, like wire~?~20,,l~:but..~include~ -a central ~- ~ ead~130 which .c~connects-~opposed ends of~ the -wire.~ he~"purpose of . ~thread 130 is to allow the wire to-be retract~d within 25 ~ the.oathe~ter~by pulling the pusher proximally within he catheter~ AWithout thread 130,c~uch pusher movement would be accommodated primarily by~the-stretching in the wire coil, rather than retr~ction of the entire wire a~ a unit. The wire may ~e formed as above, but with the inclusion of a central thread during the coil-winding process. After the coil is formed and cut, the central thread is attached, as by soldering to the S(J~STIT~J~E S~EFT

:WO92/21400l~ P ~iUS~2/04 ~

21~276 opposite coil ends, and the coil is given its convolut-ed, relaxed shape, as above.
Wire 120 is also modi~ied to include a sail or parachute 130 attached to the distal end of the coil.
S The parachute is formed of an expanse 132 of flexible material, such as thin polyethylene film, which is tie~
to the coil end by tie lines, such as line~ 1:34. As shown in Fi~ure lOB, the parachute can be fully with-dr~wn into the catheter, by pulling the clamped wire proximally with the pusher. When the pusher is ad-vanced distally, as in Figure lOB, the parachute is advanced beyond the distal end of the catheter, and can "open" in blood flow past the parachute (indicated by - -- arrowC 136 in the figure). That is, the parachute, ~- : 15:- which is also-referred to herein as flexible distal-end tructure, is open to provide increased are~ of contact -` with blood flowing through the vessel in a left-to~
right direction in the figure.l44 :In this condition, the distal end of the catheter is carriad in the direction of-greatest blood flow.
The operation -of ~apparatus 120 in a cath~ter ~5~ ? t~ _ guidance method is iiilu~tratedi~in ITigure 11, which ~: ~ S~ hows the:distaI end ofSthe-c`atheter~in a Yessel 138, - just upstream of a-vessel branch 140 at which the 25 - vessel bifurcates into larger and:~maller vessels 142, nx~ respe~tively. It is assumed that`the desired dire~tion ~ of movement of the:c~theter is`~into vessel 142 having - ` ; the greater volume-flow rate. When the vessel branch : is reached, the user advances the pusher to move the D di~tal end of wire 128 from its position shown in Figure 8A to that shown in Figure 8B, where the para-chute is open and carried in the direction of greater SUBSTITUTE SHEET

WO92/21~ PCT/~S92/ ~ 1 2~L13276 blood flow, i.e., toward vessel 142, ~s indicated. ~
catheter is now advanced as a unit, with blood flow tending to carry the catheter end into vessel 142.
After the catheter end is within vessel 142, the pusher S may be retracted to draw the parachute into ~he distal catheter end. The parachute is maintained in its with-drawn position (Figure 8A) when a vessel branch is encountered, and it is desired to follow the smaller of the two vessel branches. Thus, catheter guidance along a series of vessel branchec may be accomplished ~y alternately extending the parachute, when t~e larger of two vessel branches is to be followed, and retracting the parachute when the smaller o~ two branches is to be followed.
15 - When the des~red vaso-occlusion site i~ reached, the wire is -advanced into the vessel 8ite, and posi-tioned and oriented as a~ove, before being released from it~ clamped position.
~ he e~bodiment of the inven~ion illustrated in Figure~ 12-14 is i~tended for cathet~r guidance by wire-directed ~ovement of a catheter in the direction of~wire ~end. ~Figures 12A and 12B show ~ distal end , ~-7-regio~i~of a catheter appar~tus 140 designed for ~uch wire-directed mo~ement through and within a vessel 142.
~25 ~The~apparatus~includes a catheter 144, a pusher 146, - - iand a~Yaso-occlusion-wire 148~ The pusher and wire are - ` ~ec~red in a cl~mped condition-in the wire by cl~mping ~tructure lS0 8UCh` -as described above with respect to Figure 2. Catheter 144 differs from that shown in Figures 1 and 2 only in the construction of wire 148, as follows.

SU~Tt ~'J, ~ S~EET

.WO 92/214Y)O ` Pcl~/usg2/o46~L~

2 7 ~

Wire 148 is formed of a coil winding 149~ like wire 20, but includes a central torqueable wire band 152 which connects opposed ends of the wire~ Band 152 serves three purposes: First, it provides a substan-tially inelastic connection between opposite ends ofthe coil winding, to allow the wire to be retracted in the catheter. Secondly, it provid~is torquea~le struc-ture which allows wire 148 to be torqued during cathe-ter guidance. Finally, the band provides a bent tip 154, as seen in Figure 12B, which can be oriented for catheter guidance, as described below.
The wire also includes a modified radial enlarge-ment 156 designed to allow transmissio~ of torque from the guidewire to the wire. With reference to Figures 13 and 14, the enlargement includes a pair of radial ~- - posts, such as 158, extending from opposite sides of a - spherical structure 160 which is captured in pusher clamp 152 within the catheter. As can be appreciated from Figure 14, the posts serve to engage the sides of the clamp jaws 164~ 166, w~en the clamp is rotated, to ~: ~.. rotate the radial enlargement,~and with it, the vaso-~occlusion wire. Thus,.~torque applied to the pusher is ~io~ effecti~ely transmitted to the wire band, to rotate the vaso-occlusion wire within the catheter.
-~ 25 Figures 15 and 16 illustrate two alternative embo diments of wire-clamping structure-which provide posi-~- tive-torque transmission-between a pusher and wire in the invention, i.e., clamping structure w~ich could be used in apparatus 140. Shown in Figures 15A and lSB is a clamping structure 170 which includes-confronting end regions of a pusher ~72 and a vaso-occlusion wire 174.
A clamp 176 in pusher 172 has a pair of expandable jaws SUBSl l~UTE SHEET

~0~92/214~ 7~ PCT/US92/04~1 21ii~276 176, 178, similar to clamp 30 shown in Figure 2, but where each jaw includes an inwardly projecting pin, such as pin 180. The jaws are expandable between a closed position in which the jaws are constrained by co~tact with the lumen walls of a catheter 182, as ~hown in Figure 15A, and an open condition in which the jaws are positioned beyond the distal end of the cathe ter, shown in Figure l5B.
A radial enlargement 184 in wire 174 has a spheri-cal shape, as in the Figure-2 embodiment, but includes a central bore 86 dimensioned for receiving the clamp pins in the opposite ends of the bore, as shown in Figure 15A. The locking action of the pins in the bore, in the clamp's closed condition, provide posi-~15 tive tcrgue transmission betwe~n the pusher and wir~,as can be appreciated.
When the pusher is advanced to move the clamp beyond the distal end of the catheter, as shown in Figure 15B, the clamps open to their relaxed condition, : freeing the radial:enlargem~nt for movement out of the ~-. - jaws, as indicated. ~
,rThe -clamping~tructure shown in~Figures 16A and - 16B, and indicated generally at l90, includes a clamp 192 forming the distal end of a pusher 192, and a :.~ 2S planar loop 194 forming .the proximal end of a:vaso-occlusion wire 196.~i Clamp 192 has a pair of expandable jaws 198, 200, similar to clamp 30 sho~n in Figure 2, but where each jaw includes an inwardly pro~ectin~ pads 202, 204, respectively which haYe flat confronting surfaces for contacting the wire loop, when the clamp is in a closed condition. As above, the jaws are expandable between a closed position in which the jaws S~s~t~3~ b.~T

WO92121400 PCT/US92/ ~ ~

~ 11 0~7~

~re constrained by contact with the lumen walls o~ a catheter 205, as shown in Figure lSA, and an open condition in which the jaw~ are positioned beyond the distal end of the catheter, shown in Figure 15B.
A channel 206 formed in pa~ 204 is adapted for receiving a pin 208 in pad 202 when the clamp is in a closed condition. The pin pr~vent~ the wire loop from escaping from the clamp, with such in a closed condi-tion, but readily allow the loop to be released from the clamp when the clamp opens, as shown in Figure 16B.

The operation of apparatus 140 in a catheter guid-ance method is illustrated in Figure 15, which shows - the di~tal and of the catheter in a vessel 158, just -15 upstream of a v~ssell branch 160 at which the vessel bifurcates into larger and smaller-ves~ls 162, 164, respectively. It is assumed that the d~sir~d direction of movement of the catheter is into vessel 164 having the lower volume-flow rate. When the vessel branch is reached, the user advances the pusher to extend wire tip 154 beyond the distal end of the o theter, as shown inr~Figuré 12B. The-pusher-i~-then torgued to rotate -the~*ip in the direction of~thelvessel pathway, e.g., . toward vessel 164,~as 8hown in Figure lS. The catheter ---25 ~ then advanced along the vessel pathway, with the wire tip guiding the~oathet~r into the selected vessel branch.
Catheter guidance along a series of vessel branch--:es is thus achieved by employing the vaso-occlusion wire 2S a bent-tip guide wire, for guiding the catheter along a tortuous path to a selected vaso-occlusion site. When the site is reached, the wire is the ad-SUBSTI~UTE SHEET

~WO92/21400 ~ PCT/US92/04~1 2~ lC276 vanced into the vessel site, and positioned and orient-ed as above, before being released from its clamped position.
From the foregoing, it will be appreciated how various objects and features of the invention are met.
First, in the catheter operation of placing a vaso-occlusion wire at a vascular site, the present inven-tion allows the wire to be moved within the site, under positive clamping to a pusher, until the wire is pro-perly positioned and oriented within the site, to op-timize its intended vaso-occlusion function. Secondly, even after the wire is released from the pusher, the wire can be reclamped for further orienting changes in the vessel or to retrieve ~he wire from ~he ~ite.
:; 15~he construction of the app~ratus requires rela-tively~simple modifications of confrnn~ing ends of a conventional puæher and wire, for use with a conven-tional catheter.
Finally, the wire in the apparatus can ~e readily - ~ 2~ adapted, as descri~ed-in Section C, for use both in guiding a:small-diamèter-"catheter through a tortuous vessel~'path,;'and~-as ra vaso-ocelusivê wire, once the ~ lected:occlusion~s~té'is reached. The wire may be : : de~igned either. for ~flow-directed or wire-directed movement along the vessel pathway.
Although the invention has been described with ~ ~' respect to particular embodiments ànd methods, it will ~be appreciated that various changes and modifications may be made without departing ~rom the invention.

!

SUBS T iT~ T

Claims (29)

It is claimed:

1. Apparatus for use in producing vaso-occlusion at a selected site in a body vessel comprising a catheter having proximal and distal ends and an interior lumen extending therebetween, and adapted for placement of its distal end adjacent such selected site, a vaso-occlusion wire extendable from a relaxed condition capable of assuming a convoluted condition, to an extended, linear condition in which the wire can be advanced through said lumen, a pusher which is controllable from the proximal catheter end to advance said wire, with such in its extended condition, through said catheter by contact between confronting ends of the pusher and wire, a radial enlargement carried on one of such confronting ends, and expandable clamping structure associated with the other of such confronting ends for movement between a closed condition produced by contact of the structure with the catheter lumen, in which the clamping structure is effective to hold the radial enlargement in clamped engagement, and an open condition in which the clamping structure is expanded to release the radial enlargement, and release means in said catheter, adjacent its distal end, for releasing the clamping structure from its closed to its open condition when a selected portion of the wire has been advanced beyond the distal catheter end.

2. The apparatus of claim 1, wherein said radial enlargement is carried on said wire, and said clamping structure is associated with said pusher.

3. The apparatus of claim 1, wherein said clamping structure is an expandable coil for expansion between a closed, more coiled condition produced by contact of the coil with the catheter lumen, in which the coil is effective to hold the radial enlargement in clamped engagement, and an open, less coiled condition produced by interaction of the jaws with said release means, in which said coil is expanded to release the axial enlargement.

4. The apparatus of claim 3, where in said radial enlargement is carried on said wire, and said coil is associated with said pusher.

5. The apparatus of claim 3, wherein said radial enlargement is carried on said pusher, and said coil is associated with said wire.

6. The apparatus of claim 1, wherein said release means is defined by the distal-end of said catheter.

7. The apparatus of claim 1, wherein said release means includes a radially enlarged segment in said catheter lumen, adjacent the catheter's distal end.

8. The apparatus of claim 1, wherein said wire includes an elongate coil whose opposite ends are connected by a substantially inelastic thread.

9. The apparatus of claim 1, for use in guiding the catheter through a branched vessel path by flow-directed movement of the catheter's distal end, wherein said wire includes flexible distal-end structure which, when advanced beyond the distal end of the catheter, is adapted to open to provide increased area of contact with blood flowing in a vessel.

10. The apparatus of claim 9, wherein said wire includes an elongate coil whose opposite ends are connected by a substantially inelastic thread.

11. The apparatus of claim 1, for use in guiding the catheter through a branched vessel path by wire-directed movement of the catheter's distal end, wherein said wire is torqueable and includes a distal end region which assumes a bent configuration when the end region is advanced beyond the distal end of the catheter, and said clamping structure is effective to transmit torque between said pusher and said wire, with such in the catheter lumen.

12. The apparatus of claim 11, wherein said wire includes an elongate coil whose opposite ends are connected by a torqueable, substantially inelastic band.

13. A pusher-and-wire assembly for use with a catheter having proximal and distal ends and an interior lumen extending therebetween and which is adapted for placement at a selected vessel site, comprising a vaso-occlusion wire extendable from a relaxed condition capable of assuming a convoluted shape, to an extended, linear condition in which the wire can be advanced through the lumen of such catheter, a pusher which is operable from the proximal catheter end to advance said wire axially, with such in its extended condition, through said catheter by contact between confronting ends of the wire and pusher, a radial enlargement carried on one of such confronting ends, and expandable clamping structure associated with the other of such confronting ends adapted for movement between a closed condition produced by contact of the clamping structure with the catheter lumen, in which the structure is effective to hold the radial enlargement in clamped engagement, and an open condition produced by expansion of the structure, in which the enlargement is axially releasable from the structure.

14. The assembly of claim 13, wherein said clamping structure includes expandable jaws adapted for movement between a relaxed, open condition and a closed condition produced by contact of the jaws with the catheter lumen.

15. The assembly of claim 14, wherein said radial enlargement is carried on said wire, and said jaws are associated with said pusher.

16. The assembly of claim 14, wherein said claiming structure includes an expandable coil adapted for expansion between a closed, more coiled condition produced by contact of the coil with the catheter lumen, and an open, less coiled condition, in which said coil is expanded to release the radial enlargement.

17. The assembly of claim 16, wherein said radial enlargement is carried on said wire, and said coil is associated with said pusher.

18. The assembly of claim 16, wherein said radial enlargement is carried on said pusher, and said coil is associated with said wire.

19. The assembly of claim 13, wherein said wire includes and elongate coil whose opposite ends are connected by a substantially inelastic thread.

20. The assembly of claim 13, for use in guiding a catheter through a branched vessel path by flow-directed movement of the catheter's distal end, wherein said wire includes flexible distal-end structure which, when advanced beyond the distal end of the catheter, is adapted to open to provide increased area of contact with blood flowing in a vessel.

21. The assembly of claim 20, wherein said wire includes an elongate coil whose opposite ends are connected by a substantially inelastic thread.

22. The assembly of claim 13, for use in guiding the catheter through a branched vessel path by wire-directed movement of the catheter's distal end, wherein said wire is torqueable and includes a distal end region which assumes a bent configuration when the end region is advanced beyond the distal end of the catheter, and said clamping structure is effective to transmit torque between said pusher and said wire, with such in the catheter lumen.

23. The assembly of claim 22, wherein said wire includes an elongate coil whose opposite ends are connected by a torqueable, substantially inelastic band.

24. A vaso-occlusion wire for use with a catheter having proximal and distal ends and an interior lumen extending therebetween and which is adapted for placement at a selected vessel site, and a pusher which is operable from the proximal catheter end for radial movement through the catheter lumen to a release position, said pusher including a clamping structure, comprising an extendable, torqueable wire portion which is extendable from a relaxed, convoluted condition, to an extended, linear condition in which the wire can be advanced through the lumen of such catheter, and a radial enlargement carried at one end of the wire portion for torqueable clamping engagement with and release from the clamping structure in the pusher.

25. A method for placing a vaso-occlusion wire at a selected site in a vessel, where the catheter is guided through a branched vessel path by flow-directed movement of the catheter's distal end, comprising guiding the distal end of a catheter to such site, by advancing within the catheter by means of a pusher a vaso-occlusion wire which is extendable from a relaxed, convoluted condition, to an extended, linear condition, where said wire includes a flexible distal-end structure which, when advanced beyond the distal end of the catheter, is adapted to open to provide increased area of contact with blood flowing in a vessel, and said advancing includes (a) advancing the wire distally, to advance said structure beyond the distal end of the catheter, when it is desired to guide the catheter into a vessel branch having greater fluid flow at a branch point, and (b) retracting the wire proximally, to draw said structure within the distal end of the catheter, when it desired to guide the catheter away from a vessel branch having greater fluid flow at a branch point, and during said advancing, maintaining the wire in a clamped condition to said pusher in which the wire can be moved axially in both directions within the catheter, until a selected portion of the wire has been advanced beyond the distal end of the catheter, at which point the wire is released from its clamped condition.

26. A vaso-occlusion wire for use with a catheter having proximal and distal ends and an interior lumen extending therebetween and which is adapted for placement at a selected vessel site, and a pusher which is operable from the proximal catheter end for radial movement through the catheter lumen to a release position, said pusher including a clamp structure, comprising an extendable, wire portion which is extendable from a relaxed, convoluted condition, to an extended, linear condition in which the wire can be advanced through the lumen of such catheter, said extendable portion including an elongate segment whose opposite ends are connected by a substantially inelastic member, and a radial enlargement carried at one end of the wire portion for clamping engagement with and release from the clamping structure in the pusher.

27. The wire of claim 26, wherein said member is a torqueable band adapted to transmit torque from said radial enlargement along the length of the extendable portion.

28. A vaso-occlusion wire for use with a catheter having proximal and distal ends and an interior lumen extending therebetween and which is adapted for placement at a selected vessel site, and a pusher which is operable from the proximal catheter end for radial movement through the catheter lumen to a release position, said pusher including a clamp structure, comprising an extendable, wire portion which is extendable from a relaxed, convoluted condition, to an extended, linear condition in which the wire can be advanced through the lumen of such catheter, said wire including flexible, distal-end structure which, when advanced beyond the distal end of the catheter, is adapted to open to provide increased area of contact with blood flowing through a vessel, and a radial enlargement carried at one end of the wire portion for clamping engagement with and release from the clamping structure in the pusher.

29. A method for placing a vaso-occlusion wire at a selected site in a vessel, where the catheter is to be guided through a branched vessel path by wire-directed movement of the catheter's distal end, comprising guiding the distal end of a catheter to such site, by advancing within the catheter a vaso-occlusion wire which is extendable from a relaxed, convoluted condition, to an extended, linear condition, where said wire includes a distal-end segment which assumes a bent configuration when the end region is advanced beyond the distal end of the catheter, and said wire can be torqued remotely as it is advanced within the catheter, and said advancing includes (a) advancing the wire distally, to advance said segment beyond distal end of the catheter, when it is desired to guide the catheter into one of two vessels at a branch point, (b) torquing the wire to orient the bent segment of the wire in the direction of the one vessel at the branch point, and (c) advancing the wire distally to guide the catheter into the one vessel, and during said advancing, maintaining the wire in an axially clamped condition in which the wire can be moved axially in both directions within the catheter, until a selected portion of the wire has been advanced beyond the distal end of the catheter, at which point the wire is released from its clamped condition.