CA2127713C

CA2127713C - Ultrasoft embolism devices and process for using them

Info

Publication number: CA2127713C
Application number: CA002127713A
Authority: CA
Inventors: Alejandro Berenstein; Ivan Sepetka; U. Hiram Chee; Wendy Zenzen
Original assignee: Target Therapeutics Inc; New York University NYU
Current assignee: Target Therapeutics Inc; New York University NYU
Priority date: 1992-11-18
Filing date: 1993-10-15
Publication date: 2000-02-22
Anticipated expiration: 2013-10-15
Also published as: DE69318540D1; EP0623012A1; DK0623012T3; CA2127713A1; US6458119B1; US5826587A; US5718711A; DE69332915D1; AU665291B2; EP0824011A1; ATE165965T1; IL107337A0; ES2116472T3; AU5362894A; DE69332915T2; EP0623012B1; ATE238001T1; DE69318540T2; EP0623012A4; ES2193311T3

Abstract

This invention is an exceptionally flexible, ultrasoft vaso-occlusive or embolism forming device. It is made of radiopaque material which maybe a braid (200), coil (100); or chain (600) which forms a long, thin thread-like device having little rigidity or column strength. The diameter of the device may be less than about 0.010 inches. The filamentary material making up the device used to form the coil (100), braid (200), or chain (600) is typically of a diameter less than about 0.002 inches. The device is sufficiently flexible and small that it maybe hydraulically delivered to a site within the vasculature of the human body using an injected drug or fluid flush through a catheter (512). In some configurations, the device may be delivered using pushers (504, 512) to mechanically deliver the device through the catheter lumen. Various mechanical connections may be used to sever the coil by a simple connection of a dissimilar metal to allow electrolytic separation upon application of small voltage is desirable (Figs 5A, 5B).

Description

'N6~~ 94/10936 ~ ~ ~ ~ l ~ ~ 1PC1'/LJS93/~9914 -1_ ._ ..
PJL'i'RASOF'~' EIVISOL1SI~1 ~EVICES A(VD PROCESS FOR USING
ao Field of the 7Cnvention This invention is an exceptionally flexible, ultrasoft vaso-occlusive or embolism forming device. ~t is made of a radiopae~ue material which may be a braid, l 1~ a long, thin threadlike device coil, or chain which f~rms havimg little rigidity or column s~r~ngth. The diameter of the device may be less than about ~.Olo inches. The filamentary material making up the device used to form tie ~~i3., braid, or chain is typically of a diameter less ~o .fan abut ~.0~2 anch~s~ The device is sufficiently flexible and small $:hat it gay be hydraulically delivered t~ a ~xte ~it~in the vasculature of the human body using an ~.n' ~c~eddru~ ~r f lu~d f lush thr~u~h a catheter s ~n srrm~ c~n~ig~.arati~~s; the device may ~~ dez~.~r~rea using 25 gushers t~ ~echaraica7.ly d~exivW r tine dev~i~ce through the ~,a~.,ter.~um~s~w ~ara.~us,me~rhan~calc~e~.lcna~lmay be used to ~'a.IPr~V~.r the c~3,.1 bLlt a s~mp~.e coIll3ectlon of a dissimilar metal t~ allow elects~lartic ~s~paratioaa upon ~ppyidat~:~n ~f a small' voltage is desir~b~.e. The device 30 assumes a rend~m mass ~f threadlike materiel after being ~~ected from the catheter tip at the chosen vascular Slt~. ~flell the dev3.CE is 3 CC3.1, the COll may be a singJ.~ or of multiple helices. The ~dwi~e ~wrhether coil o r braid ~r chain] gay be used alone,o~ in conjunction 35 r~ith larger coils or braids to achieve a denser occlusion s.
f V610 94d10936 s ~ ,,~ r~ . 1~ PCT/~)593/09914 .. ~ ..i. ~ ~
...
or with fibrous thrombotic attachments or as a substrate to localize the subsequent infusion of tissue adhesives, particulate embolization devices, or chemotherapeutic agents in abnormal blood vessels and tissues. The device ' may be used for the temporary occlusion of blood_vessels during types of diminished blood flow testing. The invention also includes processes for introducing the devices iwto the human body.
BAOKGROUND OF THE INVEIJTION
Endovascular therapy has been used in treating a variety of different conditions, including control of internal bleeding, occlusion of blood supply to tumors, and relief o~ vessel wall pressure in the region of aneurysm. A variety of different embolic agents are known as arguably suitable for such therapy. .
One kn~wn embolic agent includes in~ectable fluids or susp~nsa~ns, such as ~aicrofibrillar collagen, various pol~nreric bead, and pol~rv3nyl alcohol foam. The polymeric agents may be additionally crosslinked, se~metimes ira vivo, to extend the persistence of the agent ~at the desa.red vascular side. These agents are often introduced into the v~schlature through a catheter.
after such intr~ducti.on, materials there form a solid 25~ space-filliragr mass. filth~ugh they provide good shogt~
.~~verso-occlusion, they are ultimately reabsorbed in the process of vessel recanalization.
po~;ymer resins, typically cyanoacrylates, are also employed as injec~able verso-occlusive materials. The 3~ resihs are typically mixed with a radio-opaque contrast material or made radiopaque by the addition of tanta3:um powdsr. Their use is fraught with problems in that placement of the mixture is quite difficult. Inadvertent ~~nbolisxns in normal vasculature (due to the inability of 3~ controlling tlhe destinati~n of the pre-gelled resins is WO 94! 1 ~936 ; ; ~, ~ ~ ~ ~ ~ ~; , . . . '"~1~~~3109914 _g-not altogether uncommon. The material is also difficult or impossible to retrieve once it has been placed in the vasculature. Such resins have not been F1DA approved, and a waiver must be reguested in each instance where the materials are applied during human operative procedures.
A number of mechanical vaso-occlusive devices are widely used. One such device is a balloon which may be carried to the vessel site at the end of the catheter and there inflated with a suitable fluid, typically a polymeri~able resin, and released from the end of the catheter. The balloon device has the advantai~e that it effectively fills the cross-section of the occluded vessel. However, when using intravascular balloon emboli~ation of intracranial berry aneurysms, inflation of a balloon into the aneurysm carries some risk of aneurysm rupture due to possible "overfilling°' of portions of the sac and due to the traction produced when detaching the ball~~n from the end of the catheter.

2~oreover, a vascular balloon is difficult to retrieve after the resin within the balloon sets up, and the balloon cannot be easily visualised using radiographic techniques unless it ~s fZlled wZth c~ntrast materxale balloons have also been known to rupture during filling, or release prea~atur~ly dura.ng filling, or leak monomeric resin into the vas~ulature during the period before the monomer sets up unto polymeric form.
Another type ~f mechanical vaso~occlusive device is a raise coil or braid which can be introduced through a datheter;in stretched linear form and assumes an irregular shape upon discharge of the device from the end of the esthetes. A variety ~f vaso-occlusive coils $nd braids arm knbwn. For instance, U.se Fatent ~,gg~,069, to Ritchart et al., shows a flexible, preferably coil~c~, wire for use in small vessel vaso-occlusi~n. Unlike verso-occlusive coils previously, ~J6~0 9411 X0936 . _ , P ~'/ US93>Qy914 s. ~~ ~.~ ,. _4_ . .
._ Ritchart et al. teaches a coil which is fairly soft and is delivered to the site using a pusher within a catheter lumen. The Ritchart et al. coils are typically pushed into the desired vascular site in a linear configuration.
Upon discharge from the catheter, the coil may.undertake any of a number of random or regular configurations designed to fill the site. The coils are used for small vessel sites, e.g., 0.5-6 mm in diameter. The coils themselves are said to be between 0.010 and 0.030 inches in diameter. The length of the coiled wire is typically 15-20 times the diameter of the vessel to be occluded.
The wire used to make up the coils may be 0.002 to 0.00 inches in diameter. Tungsten, platinum, and gold threads or wires art said to be preferred. These coils have a variety of benefits, including the fact that they are relatively permanent, they can be easily imaged radiographically, they may be located at a well-defined vessel site, and they can be retrieved.
A variation of the mechanical endovascular coil is the elects~lytically detached endovascular coil described in U:S: Patent 5,1220132, to Guglielmi et al.
~ugl.ielmi's coils are ~ypiGally used in intracranial aneurysms because of their effectiveness in quickly forming controlled emboli. The disclosed coils are sima.7:ar to those ~f 'Ritcha~rt et' al: in size and in composition. However, the ~aethod of introducing the coil to the vascular site is somewhat different. Rather than mechanically.thrusting the coil into the chosen site, the coil is'placed a% the~site and a small voltage is applied to the guidewir~ supporting the coil so that the coil is ~lectrolytically detached from the distal tip of the guidewire. The step of electrolytically detaching the doll has the aclc3ed benefit of forming a thrombus as the coif is detached: ~rgain, as noted above, the Guglielmi coils may be stainless steel or platinum or the like, and W~ 9110936 ~ ~ ~ ~~ r~ ~. '~ ~ . . ,. _ ~ ~'C'I'lIJ~93109914 _5_ are typically 0.010 to 0.020 inches in diameter and are made using wire having approximate diameters of 0.001 to 0.005 inches. The coils in this service are typically between 9l and 50 centimeters in length.
~Yone of this background shows embolism-forming coils, braids, or chains having diameters less than about 0.010 inches in diameter, nor their placement by fluid delivery through a catheter.
~.~ SUI~IARY 4F TgIE INZ7ENTION
This invention is an exceptionally.flexi,ble, ultrasoft verso-occlusive or embolism device. It may be a braid, coil; or chain and is made of a radiopaque material forming a 7.ong, thin threadlike device having little rigidity or column strength. The diameter of the device may be less than about 0.010 inches, preferably less than about 0.00'5 inches in diameter. The wire making up the device is typically of a diameter less than ab~ut 0.002 inches. The device is sufficiently flexible z0 and small that it~a~ay be hydraulically delivered to a site within the vasculature of the human body using a da~h~tera The device gay b~ mechanically delivered using a pushes wire. The devises may be severed from the gusher wire usiiag s mechanical dr electrolytic connection. '~~cause o~ their flexibility and size, there is little ~pportunity for friction to develop with the catheter lien .
These devices may be used with guide wire -directed cathetersand with flow directed catheters, even 30 those which are very flexible in, their distal regions.
Th~.s invention provides opportunities for placement of e~tbolis~n-f~a-r~ing devices in vascular regions otherwise not routinely accessible due to th~~:x remote nature.
The d~trice typically assumes a loose, random 35 mass after being ejected from the catheter tip at the W~ 9~1/1d193b ~~ ~ PC'I'/~JS93/09914 s 'y,~: ~ ~ ._ .. "~' .
selected vascular site. When introduced into a high flow region, the mass ciuickly compacts into a significantly denser mass. The device, whether call, braid, or chain, a may be used in conjunction with larger coils, braids, or chains to achieve a denser occlusion or as a szabstrate to localise the subsequent infusion of tissue adhesives, particulate embolization devices, or chemotherapeutic ' agents in abnormal blood vessels andytissues, or for the temporary occlusion of blood vessels during types of diminished blood flow testing. The device may be coated with thrombotic or therapeutic materials or used in conjunction with fibrous embolic additions to the device.
The invention also include processes for introducing the devices into the human body.
~.5 ~ This invention' is also a method for first introducing a larger vaso-occlusive device, such as a .
coil, to the vascular site desired by the attending physician, followed by the introduction of the inventive device so as to fill the interstices left by the larger c~ils and thereby form a denser c~ccl.usi.on. The devices array also be introduced by themselves, if so desired.
ERIEF T3E~CR~PTI~gT f9~ TTrIE DRAWINGS
Figure ~.~ shows an enlarged side view of a~coil made according to this invention Figure iB shows an enlarged side view of a dbuble helix c~il made accor~d3ng to the invention.
F'a.gure ~ showss an enlarged side view of a braid made according to this invention~
~0 Figure 3 shows an enlarged side view of a combination coi3 and braid made according~to this ~.nvent:lon a Figure 4 is a close-up .drawing of a variation of the Figure 3 device in which a braided material is woven on the outside of the coil.

W~ 94f 10936 ~ ~ ~, ~,~ ;~ .~ ~ , ~ ~ . . PCTfdJS93l09914 ~ '. ~ ~ a ._ Figures 5A and 5B are close-up views of ends of coils made to use electrolytic separation from a wire pusher.
Figure ~A shows an enlarged side view of a chain made according to this invention and Figures GB and sC show an inventive chain having attached fibrous material.
Figure ? is a clinical set-up which may be used hydraulically to introduce the coils into the vasculature. , Figure 8 shows a method for mechanically introducing one ~r more of the inventive,devices into the vasculature.
Figure 9 is a graph comparing deflection versus extension for three coil; one coil made according to this invention and two commercially available embolism coils made ~ener~ll.y according to the prior art.
DESCRIPTION OF THE IN~7ENTION
Figure 1~ shovrs a coil (100) made according to this invention. It is a fairly straightforward device typica~.ly formed b~ wrapping or grinding a fine filament or wire ( x.02 ) , preferably having' a di~~neter ( 104 ) less ~ha~ about ~. 0025 iniOlaes, preferably 0. ~0045 to about ~:00225 inches, ~nor~ preferably about 0:0~05 to 0.002 inches, most preferably ~b~ut 0.001 to 0.002 inches, about a spinning mandrel using well-known coil-maraufacturing t~chni~aes . .~ separate end cap ( 108 ) or termiaaation piece may be included at the end of the coil.
~he terminator (108) may be a separate pied or a fused, portion of the coil or a bit of a filled material such as an epo~cy. The major function of the end piece is to prevent the coil from catching on the interior of the catheter lumen or vessel: However, it is acceptable for WO 94lA0936 _ . ~'CT/US93/09914 ~~~ ;a . - , ~' : ~ . .
_8_ devices of this size to simply cut the coil ends and not use a terminator (108).
In producing the coil, the coih-manufacturing method is adjusted to produce a single~layer coil typically with a minimum helical pitch, that i~ to say, the windings are fairly closely packed. Typically, the mandrel will be of such a diameter that the outside coil diameter (106) will be less than 0.010 inches, preferably 0.0014 to 0.0095 inches, more preferably between 0.004 1o and 0.0095 inches, and most preferably between 0.004 and 0.0075 inches. The soft, flexible coil thus produced is cut to desired lengths after removal from the mandrel.
We have f~und that the device is especially suitable fox the noted service when the device (coil, braid, or combinatian) deflects more than about 20° (preferably more than about 35°) under its own weight over the first , centimeter of length, When supported at a single end.
The length of the coil may be between 2 mm and 120 cm, typically between 30 cm and x.20 cm.
2Q Instead of the filament shown in Figures lA and 1B, the coil may be pxoduced from a ribbon whose ma~Or axis is between 0'.001 and 0.002 inches and whose minor ax~.s is 0p0004 end Os001 inches: C~ils produced from gibbons are often modex°ately stiffer than those produced '25 frflm similar~:y sized filaments. Smaller diameter coils are often more readily produced:
The regularity of winding shown in Figure lA is not ~andatoxlt; th~ windings may be rTregular or of varying pitch: The coil (100) shown in Figure lA and ~B
30 (and the variations of the invention which are described below) may be 'produced from any ~f ~ number of dif f event ~ateriels. Some portion of the material must be ~.ad~.opaque s~ that the coil aa~d its positi~n may I~e readily monitored within-the human vasculature. Suitable 35 materials include bioGOmpatible metals, polymers, and ' dWWI.D 94/20936 ~: ~.'~°'"~ °~ ~ , , " .~ ~; ;. . PCf/US93/09914 L' .Ji. :~~i 4 ~ ~ ' .
~9~
alloys. For instance, biocompatible, radiopaque metals include silver, gold, palladium, platinum, tungsten, iridium, and various stainless steels. Other alloys such as platinum and tungsten (preferably 92% platinum and 8%
tungsten) are suitable and, indeed, are often,m4st preferred. The platinum-tungsten alloys desirably have a tensile strength of at least about 180 kpsi and, for a wire of a nominal 0.001" diameter, have a breaking load of 0.17 lb with a minimum elongation of 2% measured at a speed of 1.0 in/min. Various biocompatible polymers including polyethylene, polyurethane, polyprcipylene, and the like are suitable for use in these devices, but, because of their lack of radiopacity, must usually be teamed with a radiopaque marker or filled with a radiopac~ue filler to allow proper positioning of the coil within the body. Similarly, other inorganic materials such as fibrous carbon are suitable and may be used in the inventi~n.
After formation of the coil, its interior may be filled wa.th a drug material such as a drug concentrate and its ends partially sealed for slow drug release from the c~il in an in vivo squeous environment. The ends of the c~il may be sealed by a water-soluble plug for storage~ if so desireri: The coil may also ( or ?5 alternatively) be coated with a thrombotic or medicinal mater~.a~ o Fa.c,~are 1~ shows ~ double helix coil made according to the invention. In this va~fation, a first coil (110) is wound along with a second coil (112). ~ne of the coils xs a fine wire, the second coil may also be a ware or it may be a partially hardened fibrous aonaterial, e.g., a material or synthetic fiber, such as y~$cron ox silk or other thrombotic material. The double helix metallic wire coils made acc~rding to this variation of the invention are made using the procedure PC'd'/iJS93/09914 9aV~ 94/1Q936 , ~ ~4~

~ i x discussed elsewhere in this document. The double hel coils in which the second coil is a material or synthetic fiber, typically requires some modest heat treatment after winding to set the fiber in the forma of its ' metallic spring colleague. For ~Dacron or sill,.this may be done by steaming the wound spring at reasonably low temperatures, ~.g.,~ 300F ar so, to form the fiber without fusing it.

Figure 2 shows a braided (or otherwise) woven to vaso-occlusive device (200) made according to the invention. The braided occlusive deva.ce (200) is tubular and produced by weaving fibers or wires over a mandrel much in the same way the coil of Figure 1 was made.

Woven braids of this size are not common but are made according to known techniques. The wire or fibers in this variation of tha invention may be any of the rad3opa~ue or polymeric materials noted above, and additionally the bxaid may be made of a combination of those materials exth.er alone ox in comb~.nation with other 2~ suitable polymeric or filamentary materials such as Oacr~n, cotton, or other materials. organic fibers such as silk; ~acron; or cotton provid~.a reedy substrate for clot formati~n in the interior region of a vessel. Often the radiopeque portion of the coil pro~3des only a way to anchor the'coil ~nto the vessel wall at the site of release.

The Figure 2 braid ~r woven device (Z00) is of a diameter (204) similar to the coil (106) in Figure 1.

The braid gay have a termination-piece or section (204) 3~ similar in constitution to the analogous portion shown in Figure 1. above. The. length of the braid' may sa.mila~ly be 2 mm to l~f cue:

1i~re 3 shows a side view of a combination coil/braid vases-occlusive device according to the inventi~ns This combination is a sequence of coils (302) ~J' ~ ~ t, ; ~ PGT/~J'S93/099~4 CVO 94/10936 ~, J n and braids (304) similar in make-up and sire as the devices shown in Figures 1 and 2. Zengths of various coils (302) and braids (304), each often 2 mm to 20 cm in length, are joined together at their respective ends to form the combination device. The overall length.of the device, as with those above, may be 2 mm to 120 cm. The device may also have caps or termination pieces (306) on the ends of the device.
Figure 4 shows another variation of a coilgbraid combination (400). In this variation, however, as is shown by the cutaway insert, the substrate coil is identical to the coil shown in Figure 1 herein.
The braid is woven on the exterior of the coil. In this instance, the braid is more desirably a fibrous material such as Dacron, or cotton. The braid may, however, be a radiopaque material such as the metals and alloys and polymers discussed above. The braid may be joined by welding, melting, or by adhesion t~o the underlying coil (~02) .
Figures 5~ and 5~ show in partial cutaway, side views of soils which ~aay be delivered using a pusher such as a guide ~rire and array be detaclxed electrolytically using a proced~xre, such as that found in Guglie~.mi et al.
as d~~cussed. aboveA
Fa:gure 5A is a very enharged side view of one embodiment of this invention in which the guide ware (504) aa~d a~porti~n of the coil of (506) are shown in a ~~ial cross sectional view. A guide wire (504) which may be coated w~.th ~EfILDN or other suitable insulating 3~, material, which coating, is not shown, may be placed within a catheter l.u~en such as is shown in Gug7.ielmi et al. or as is discussed elsewhere in this document. The guide wire (504) typically has a diameter of 0.010 to Oa020 inches diameter in the portion m~re proximal of the portion shown in the drawing. In the Figure 5A portion, W~ 94!10936 r ' . ' . '~ PC,Tl1JS93l09914 ._ . .
guide wire (504) is tapered at its distal end to a point (508) within coil (506). Guide wire (504) may be joined at one or more locations, e.g., joint (510) at the distal end or joint (512) proximal of the distal end. These joints (510) and (512) may be made by soldering or the like.
Figure 5B shows a similar coil guide ware assembly (502) in which a similar guide wire (516) is introduced actually axially within coil ('506). The guide wire (516), in this variation, tapers ~cyuicklY to a very fine wire portion of (51.8). The most distal portion of a fine wire (518) is joined with coil (506) at junction of (520. Preferably a second joint (522) is made at the proximal end of fine wire (518). This variation of the invention permits substantially greater flexibility than the variation shown in Figure 5A, at least for the region, distal of joint (522). However, the safety factor inherent in having two joints fixing the guide ware or core wire (516) ~em~in in existence.
Because of the significant lack of column strength the coils used and portrayed in Figures SA and 5B, it may be de~ir~ble in some instances to introduce the coil not ~n~ly using respectively guide wires (504) in Figure 5A 'end guide wire (5i6) in Figure 5B as pushers, but also t~ ~ndve these.Coils along through the lumen of the c~t3ieter using an ancillary saline hgdraulic push.
the Boils of (506) ire detached from the respective guide wires (504) and (516) by imposition of a direct current to the c$uide wires from a power supply exterior to the body. The current flow from the coils of (506) within, the vasculature site causes a thrombus to'form by electr~thromb~osis: Typically, ~ DG electric current of aPProximat~ly 0.01 to 2 milliamps at 0.1 to 12 volts as .
applied to the gusde wire. The thrombus forms often ~5 within three to five minutes after the imposition of such ' W~L9 9411 X936 ~ ~ ~ j ~ ~ ., .. ,' PC d°/1JS93/m9914 a voltage. The voltage flows down the guide wire through the insertion means, e.g., the respective conductive joints (e.g., (510) and 1522) in Figure 5A and (520) and (522) in Figure 5B) and through the blood or thrombus.
The circuit is completed by a negative pole placed in contact with the skin. The coil is detached from the guide wire by electrolytic decomposition of either the joints or some section of the guide wire. For a coil as small as or involved in these inventive devices, the dissolution by electrolytic action normally will take place in less than four minutes. The time of~
disintegration may obviously be varied by altering the size of the various portions of the guide wire and the area of the guide wire exposed beyond the insulation.
The current level may be altered or the flow of conductive fluids such as saline solution may be introduced to enhance the electrolysis rate.
Figure 6A shows a side view of a chain made according to 'the invention. Chain (6~Q) is produced using typical chain-making techniques. Chains of this size hre not common but are easily made according to known techniques. the ware or fibers in this variation of the nvention may be any of the radiopaque or polymeric materials n~ted above. Additionally the chain may be made of a combination of those materials either alone~or in combination with other suitable polymeric or fi3.amentary materials such as Dacron; cotton, or other ~naterials~ Organic fibers such as silk, Dacron, or cotton provide a ready substrate for clot formation in ,3 ~ the, inter 1. or regl~nof a- vessel s The F.~gure 6A chain deviee (600) is of~a diameter similar to the coil (1~6) ~;n Figure 1. The length of the chain may similarly be 2 mm t~ 120 cue:
~,i~f.e 6~ shows a side view of a chain (600) as shop in Figure 6A but having suitable polymeric 9aV0 9410936 PC,"T1U~931~3991~
..
filaments (602) such as Dacron, cotton, or other materials tied to the chain. Organic fibers such as silk, Dacron, or cotton provide a ready substrate for clot formation in the interior region of a vessel. The ' ~ Figure 6B fibers ( 602 ) are looped from spot to, spot on the chain.
Figure 6C shows a side view of a chain (600) as shown in Figure 61~ but having polymeric filaments (604) such as discussed above tied to the chain in a brush-like fashion.
Each of the variations discussed above, when provided in the proper size range and materials, is an extremely soft and flexible device, whether the device be coil or braid or chain. These devices exert little if Z5 any radial force on the blood vessels into which they are placed. They are sufficiently flexible and small that they may be carried by blood flow after ejection from the distal tip ~f the catheter by which they are introduced to a narrowing region in the vascular lumen where the device ~rerlges or r~lls upon itself and wedges within the bl~od vessel. The fluid-like pr~p~rt~.es of the device enab~.es it to donfor~ to the complex geometry of certain fragile, abnormal blood vessels, and in so doing, minimize the risk of causing trad~a to or even perforation of th~se blood vessels. Such flow properties alse~ enable p7.aceanent of the inventive device at sites in the vasculataare currently unreachable by catheteri2ation, much as those withi~a an arteriovenous malformation (lsr~TNdj .
l~lthough the device is very flexible in all of its c~nfigurations, it may be produced having a modest, amount of '°prefora~. °° By °°prefor7m~ is assent the practice Bound in Ritchart et al. discussed above, where the coil ~.~ bent or cramped in such a way that it assumes a n~nlin~ar shape anly after it eacits the catheter,lumen but passes througlh the lumen with ease. Such a treatment 'WO 94/10936 '~CT/US93I09914 ! n,p r i.r~ v ~. !d d provides some additional randomness when the coil is placed at its intended site within the vasculature.
Figure ~ shows a setup for hydraulically delivering the devices of this invention to a vascular site. In this instance, the devices -- coils are' depicted -- are held in an introducer sheath (702) and delivered through a catheter (712) to the desired site motivated by a syringe (704), containing a suitable fluid. ~'he proximal end (706) of the introducer sheath (702) is connected to the fluid-containing syringe. The distal end (708) of the introducer sheath (702) is introduced to the catheter sidearm accessory (710). The lumen in catheter assembly (712) has been previously cleared of guidewires and other interior constrictions.
The plunger on syringe (704) is simply pushed down, and the dwice within introducer sheath (702) is carried down through catheter (712) to the, injection site. After the device is injected to the desired site, additional devices may be injected by swapping another introducer sheath (702) with its re~.ated device.
This procedure may be carried out after the catheter has been used to introduce coals of larger size to a particu~.ar site. The later introduction of the devices of this invention wild. enhance the throa~nbotic potential of ~the earlier-intr~duced coil in that the inventive devices will tend to fill the interstices left by the larger c~ils and achieve a more densely packed occlusion s~.te.
Figure 8 shows a set-up for delivering coils (820) to a vascular site using a guide wire (822) as a pusher . Th3:s ~rrarage~ent uses a catheter ' ( 812 ) optionally in ce~njunction with a syringe (804) containing a suitable motivating fluid such as saline solution. At the proximal emd in this variatie~n, the optional syringe is attached directly to the catheter hub (810). The 'Vd~J 941aD936 , 1PCT/LJS93/09914 _~6-guide wire (822) in this variation is shor~inn both extending distally out of the catheter (812} and proximally out of the catheter fitting. A torque device (824} for steering the guide wire or core wire (822} may ' also be seen. Core wire (822) is in turn attached to pawer supply (826} at its positive terminal. The negative terminal of power supply (826) is in turn attached to a pad (828} which is applied to the skin to provide a complete circuit to the power supply. The current flows through guide wire (822} to the junction between guide wire (822) and coil (820} (explained in more detail with regards to Figures 5A and 5B above) through the thrombus or blood, through the skin back to the pad (828}, and then to the power supply. This is used both to create thrombi and to electrolytically sever coil (820) from core wire (822}.
Additionally, these processes may include the step of intrcaducing polymer resins, such as cyanoacrylate resins (particularly n-butylcyanoaerylate} to the intended side after.the inventive coils, braids, and chains are in place. Said another way, the inventive devices form a substrate for these tissue adhesives, or particulate embolization materia7.s such as microparticles of polyvinyl'alcohol foam, or various ch,emotherapeutic agents: The~catheters suitable for use'in introducing these devices are discussed in significant detail in U.S.
Patent 4,994,069, to Ritchart et al., as was discussed 8~~vee EXAMPLE
This example demonstrates the significant difference between a preferred embodiment of this inventive coal and-.similar commercial coils of the type WO 94/1936 , ~ PCT/~JS93/099141 ;~,~~fidt~~~e~ , discussed in Ritchart et al. The example shows how much more flexible is the inventive coil than the other coils.
Three coils were measured. Coil A was a coil made according to the invention. Coils B and C are commercially available from .Target Therapeutic$ ..
Incorporated for a variety of uses. The coils' physical descriptions are as follows.
~~BI~ I

~ COIL ! COIL O.D. L WIRE Dia. ~ PITCH

0.007 0.001 0.001 B1 0 : 010 0 . 002' 0 . 002 ' B2 0.010' 0.002 0.002+~

C O.OIS, 0.003 0.003' _ "__ _~.__.~.,.w..a ~"e~~",-".....v ~,..~.:.r.

~~Jll.Yw'9ilsaiig w.r~wrv.rvw~ rsrv~~ ~.~
An introduc~r, a tapered length of tubing having an inside diameter of'0.010 inches, was taped to 2~ an angle template taken fr~m an optica7l comparator. The respective coils were pl ced within the introduces and , allowed' to extend from the tip of the introduces at .
various lengths. The coif were extended to 1.0 cm and beyond. The introduces was held level and tha angle between the tip c~f the.introducer-and the end of the coil was measured as a function of the hngth of the coil extending fr~~ the intr~ducer. The results of the tests are shown in Table II below and in Figure 6.

'6~V0 94!10936 PCT/US93/~9914 ._ . .
TABLE II

COIL ~ A B1 B2 C
ext~ n~s~
on 0 0 ~o~ ~o~

1 0.75 ~

2 4.0 2 0 ' -3 5 . a 2 p 4 10.0 2 p 5 18.5 2 1 -24.5 2 2 _-7 33. 2 3.5 -g 42 s 5 3 ~ -9 45 3 7 -a 10 5~ 3 13 2t7 69 ~2~ 26.5 -..

2 0 n 3H ~~.... 51 47 4~ ~4 The depicted data for the inventive Coil A and the Coil C are averages of a number of measurements of similar coils The re~.a~i~nship between the e~ctension of the c~i,ls and ttaeir resulting deflection in degrees is shown 3~ in Figure 6. It is readily observed that, at a 10 mm e~tensiora, the angle of deflecti~n for the inventive: coil is about 50° For the other coils, the deflection is typically ~nly ab~ut lob of that value. Consequently, it may be understood that the bending radius of the incentive coil is much smaller, the force needed to bend ~V~ 94/10336 PC1'/US93/t19914 ~s r~ r' .r m the coil is significantly smaller, and consequently the coil will move through tortuous pathways both in the vasculature and in the catheter with significantly more ease than would be observed by the other coils.
a ..
Many alterations and modifications may be made by those of ordinary skill in the art without departing from the spirit and scope of the invention. The illustrated embodiments have been shown only for purposes 1a of clarity and examples, and should not be taken as limiting the invention as defined by the following claims, which include all equivalents, whether now or later devised.
25 '

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A flexible, vaso-occlusive device comprising a coil having an outside diameter less than about 0.010 inches, which is sufficiently flexible that a one centimeter length of the coil supported horizontally at one end will deflect more than about 20° under its own weight.

2. The device of claim 1 comprising silver, gold, palladium, platinum, tungsten, iridium, stainless steel, or alloys thereof.

3. The device of claim 2 comprising an alloy of platinum and tungsten.

4. The device of claim 1 comprising a biocompatible polymer.

5. The device of claim 4 where the biocompatible polymer is filled with a radiopaque material.

6. The device of claim 4 additionally comprising a radiopaque marker.

7. The device of claim 1 where the coil is regularly wound.

8. The device of claim 1 where the coil is not regularly wound.

9. The device of claim 1 where the outside diameter is between 0.0014 inches but less than about 0.0095 inches.

10. The device of claim 9 where the outside diameter is between 0.004 inches but less than about 0.0095 inches.

11. The device of claim 10 where the outside diameter is between 0.004 and 0.0075 inches.

12. The device of claim 1 where the coil comprises'a filament having a filament with a diameter of less than about 0.0025 inches.

13. The device of claim 12 where the coil comprises a filament having a diameter of between 0.00045 and less than 0.00225 inches.

14. The device of claim 13 where the coil comprises a filament having a diameter of between 0.0005 and 0.002 inches.

15. The device of claim 14 where the coil comprises a filament having a diameter of between 0.001 and 0.002 inches.

16. The device of claim 2 where coil comprises ribbon having a major.axis of 0.001 to 0.002 inches and a minor axis of 0.0005 to 0.001 inches.

17. The device of claim 1 where the device deflects more than about 35° under its own weight when a one centimeter length of the coil is supported horizontally at one end.

18. The device of claim 1 where the length of the device is between 2 mm and 120 cm.

19. The device of claim 13 where the length of the device is between 30 cm and 120 cm.

20. The device of claim 1 having a preformed shape.

21. The device of claim 2 additionally comprising means for electrolytically detaching the device from insertion means.

22. A radiopaque, flexible, vaso-occlusive device comprising a platinum braid having an outside diameter less than about 0.010 inches.

23. The device of claim 22 where the device comprises an alloy of platinum and tungsten.

24. The device of claim 22 where the outside diameter is 0.0014 inches to about 0.0095 inches.

25. The device of claim 24 where the outside diameter is 0.004 inches to about 0.0095 inches.

26. The device of claim 25 where the outside diameter is 0.004 to about 0.0075 inches.

27. The device of claim 22 where the braid comprises wire having a diameter of less than about 0.0025 inches.

28. The device of claim 27 where the braid comprises wire having a diameter between 0.00045 and less than 0.00225 inches.

29. The device of claim 28 where the braid comprises wire having a diameter of between 0.0005 and 0.002 inches.

30. The device of claim 29 where the braid comprises wire having a diameter of about 0.001 inches.

31. The device of claim 22 comprising both a braid and a coil.

32. The device of claim 22 where the braid comprises ribbon having a major axis between 0.001 and 0.002 inches and a minor axis is 0.0005 and 0.001 inches.

33. The device of claim 22 where the device bends more than about 20° when one cm of the device is held in a horizontal position.

34. The device of claim 33 where the device bends more than about 35° when one cm of the device is held in a horizontal position.

35. The device of claim 22 where the length of the device is between 2 mm and 120 cm.

36. The device of claim 35 where the length of the device is between 30 cm and 120 cm.

37. A flexible, vaso-occlusive device comprising a chain having an outside diameter less than about 0.010 inches.

38. The device of claim 37 comprising silver, gold, palladium, platinum, tungsten, iridium, stainless steel, or alloys thereof.

39. The device of claim 38 comprising an alloy of platinum and tungsten.

40. The device of claim 37 comprising a biocompatible polymer.

41. The device of claim 40 where the biocompatible polymer is filled with a radiopaque material.

42. The device of claim 40 additionally comprising a radiopaque marker.

43. The device of claim 1 where the outside diameter is between 0.0014 inches but less than about 0.0095 inches.

44. The device of claim 43 where the outside diameter is between 0.004 inches but less than about 0.0095 inches.

45. The device of claim 44 where the outside diameter is between 0.004 and 0.0075 inches.

46. The device of claim 43 where the chain comprises a filament having a filament with a diameter of less than about 0.0025 inches.

47. The device of claim 46 where the chain comprises a filament having a diameter of between 0.00045 and lees than 0.00225 inches.

48. The device of claim 47 where the chain comprises a filament having a diameter of between 0.0005 and 0.002 inches.

49. The device of claim 48 where the chain comprises a filament having a diameter of between 0.0005 and 0.002 inches.

50. The device of claim 44 where the chain comprises ribbon having a major axis of 0.001 to 0.002 inches and a minor axis of 0.0005 to 0.001 inches.

51. The device of claim 43 where the device deflects more than about 20° under its own weight when a one centimeter length of the device is supported horizontally at one end.

52. The device of claim 43 where the length of the device is between 2 mm and 120 cm.

53. The device of claim 52 where the length of the device is between 30 cm and 120 cm.

54. The use of a flexible, vaso-occlusive device comprising a coil, braid, or chain having an outside diameter less than about 0.010 inches to access a selected vascular site.

55. The use of claim 54 wherein the device comprises a coil, a braided tube, a combination braid and coil, or a chain.

56. The use of claim 55 wherein the device is a regularly wound coil.

57. The use of claim 55 wherein the device is a coil which is not regularly wound.

58. The use of claim 55 wherein the devices have outer surfaces and additionally comprise filamentary material attached to the outer surfaces.

59. The use of claim 54 wherein the device outside diameter is between 0.0014 inches but less than about 0.0095 inches.

60. The use of claim 59 wherein the device outside diameter is between 0.004 and 0.0075 inches.

61. The use of claim 54 wherein the device comprises a filament having a diameter of less than about 0.0025 inches.

62. The use of claim 61 wherein the device comprises a filament having a diameter between 0.00045 and less than 0.00225 inches.

63. The use of claim 62 wherein the device comprises filament having a diameter of between 0.0005 and 0.002 inches.

64. The use of claim 63 wherein the device comprises filament having a diameter of between 0.001 and 0.002 inches.

65. The use of claim 54 wherein the device comprises ribbon having a major axis between 0.001 and 0.002 inches and a minor axis is 0.0005 and 0.001 inches.

66. The use of claim 54 wherein the device bends more than about 20° under its own weight when one cm of the device is held in a horizontal position.

67. The use of claim 66 wherein the device bends more than about 35° under its own weight when one cm of the device is held in a horizontal position.

68. The use of claim 54 wherein the length of the device is between 2 mm and 120 cm.

69. The use of claim 68 wherein the length of the device is between 30 cm and 120 cm.