i, ~I2 i s I r C I ee 6g 0 -1-
AUSTRALIA
PATENTS ACT 1990 DIVISIONAL APPLICATION NAME OF APPLICANT(S): Meadox Medicals, Inc.
ADDRESS FOR SERVICE: DAVIES COLLISON CAVE Patent Attorneys 1 Little Collins Street Melbourne, 3000.
INVENTION TITLE: A METHOD OF REPOSITIONING AN IMPLANTED RADIALLY SELF-EXPANDING INTRALUMINAL DEVICE AND SUBSTANTIALLY REPAIRING A DAMAGED
VESSEL
The following statement is a full description of this invention, including the best method of performing it known to us: S 4 Q TPH 1617-93DV- 19,N7 2-* P:\OPER\A D l890620.SPE 511198
A-
A METHOD OF REPOSITIONING AN IMPLANTED RADIALLY SELF- EXPANDING INTRALUMINAL DEVICE AND SUBSTANTIALLY REPAIRING A DAMAGED VESSEL BACKGROUND OF THE INVENTION The present invention relates to a method of repositioning an implanted intraluminal intraluminal device which is useful for repairing or serving as a conduit for blood vessels narrowed or occluded by disease or for use in other body passageways requiring reinforcement or the like.
Intraluminal devices or, more specifically, endovascular prosthesis, are known for treating stenosis, stricture, aneurysm conditions and the like. These devices, which include stents and grafts, are generally implanted by a mechanical transluminal procedure. Stents are devices designed to hold open a constricting vessel and generally are not designed as conduits or bypass devices. Intraluminal or endoprosthetic graphs, on the other hand, are designed as internal bypass devices which relieve stress from the surrounding vessel wall. Often, a device of this type is percutaneously implanted within the vascular system to reinforce collapsing, partially occluded, weakened or abnormally dilated localized sections of a blood vessel. Advantages of this method over conventional vascular surgery include obviating the :need for surgically exposing, incising, removing, replacing, or bypassing the defective blood vessel. Stents are often used in combination with other endoprosthesis, such as intraluminal grafts. In some cases a stent is positioned at each end of the graft, thus allowing the graft to serve as a conduit or internal support to relieve stress from the vessel wall. The stents on each end serve to keep the lumen open and to anchor the graft in place. Attachment of the graft to the stent can be accomplished with hooks or sutures. In some instances, the stent is attached to only one end of the
ASN
VA EI D -2intraluminal graft. In this case the graft is allowed to "float" in the downstream direction of tile vessel.
Structures which have previously been used as stents have included coiled stainless steel springs; helicallywound coiled springs manufactured from an expandable heatsensitive material; expanding stainless steel stents formed of stainless steel wire in a zig-zag pattern; cagelike devices made from malleable metal; and flexible tubes having a plurality of separate expandable ring-like scaffold members which permit radial expansion of the tube. Each of these devices is designed to be radially compressible and expandable so that they will easily pass through a blood vessel in a collapsed state and can j: .radially expand to an implanted size after the problem area has been reached. None of these devices is designed retain fluid.
1V..
Each of the foregoing structures suffer from a number of disadvantages. To begin with, current stents are not designed to be contractible once deployed and therefore a great deal of care must be taken to properly position and expand the device to the appropriate size. over expansion j of a stent places unnecessary stress on an already damaged vessel. Under expansion of the stent may result in inadequate contact with the inner wall of the vessel and migration of the stent may occur.
Because the structures are designed to be delivered in a collapsed state within a blood vessel, it is difficult to ensure that the device, once deployed, will radially expand to the proper dimensions. For example, the expansion of a particular coiled spring-type stent is predetermined by the spring constant and modulus of elasticity of the particular material used to manufacture the coiled spring structure. These same factors predetermine the amount of expansion of collapsed stents -cl~YI~ i 5 i110 15 20 25
I"
j 1 1 -3formed of stainless steel wire in a zig-zag pattern.
Likewise, prostheses formed from heat sensitive material which expands upon heating have a predetermined amount of expansion based upon the alloy utilized in their manufacture.
Another type of endovascular prosthesis consists of a thin wall textile radially fixed graft, which is folded up to fit inside an introducer sheath. The graft is manufactured to a predetermined diameter. If the qraft is oversized, when displaced in the artery and subsequently expanded, the graft may not fully open leaving a fold or a crease in the graft which ry further constrict an already narrowed or occluded blood vessel. On the other hand, if the graft is too small in diameter, it will slide around in the vessel and disrupt blood flow.
As previously mentioned, intraluminal grafts are often used in combination with stents. Another disadvantage of the foregoing types of intraluminal devices is that once the device is deployed within the lumen, it is permanently and fully expanded and cannot be contracted for repositioning. It is advantageous to be able to realign an intraluminal graft which has been misdeployed through catheter malfunction or any other problem which may arise during the implantation procedure.
Generally, the present intraluminal devices once fully expanded cannot be easily moved within the lumen without surgery.
When repairing blood vessels narrowed or occluded by disease, or repairing other body passageways, the device used in repairing or supporting the passageway must be flexible enough to negotiate the curves or bends of the body passageway. Most conventional endovascular prostheses do not have the requisite ability to bend so as to be advantageously placed within the vascular system.
P:%OPERNAXDA89OW620.SPE 5/11198 -4- Accordingly, it would be desirable to develop a new and improved intralumninal device and, in particular, an intraluminal vascular graft that can be expanded to a variable size to accommodate the size of the diseased portion of the vessel and prevent migration of the graft away from the desired location and provide support functions similar to conventional stents.
Such a device is described in Australian Patent No. 674352 by the present applicant, and also herein. It would also be desirable to develop a method of repositioning an implanted radially expanding intraluminal devise or a method for substantially repairing a damaged vessel involving repositioning and/or adjusting such an implanted device.
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SUMMARY OF THE INYEN'TiQ In accordance with one aspect of the present invention there is provided a method of repositioning an implanted radially self-expanding intraluminal hollow tubular braid comprising the step of: introducing a guide wire having on its distal end at least one finger-like memnber for grasping the braid so that the braid may be repositioned within a lumen.
In accordance with another aspect of the invention there is provided a method for substantially repairing a damaged vessel comprising: providing an implantable radially self-expanding intraluminal hollow tubular braid; applying a radially inward force to said prosthesis whereby its diameter decreases to facilitate entry of said prosthesis into said vessel; delivering said prosthesis intraluminally to a site of damage in said vessel; expanding said prosthesis radially until its diameter substantially conforms to the diameter of said vessel whereby said prosthesis is substantially anchored in position; introducing a guide wire having on it distal end of least one finger-like member; grasping the prosthesis with the finger-like member; applying a radially inward force to said prosthesis whereby it diameter decreases to facilitate its being moved within the vessel; repositioning the prosthesis at a location within the vessel; and releasing the prosthesis from the finger-like member so that said prosthesis expands PIkOPER\AXD%1890620.SPE -5111193 radially until its diameter substantially conforms to the diameter of said vessel whereby said prosthesis is substantially anchored in position.
The following discussion will be directed at the two aspects of the invention described above, and also to a preferred form of the radially self-expanding intraluminal hollow tubular braid used in the methods of the invention.
The device is preferably used as an endovascular prosthesis in which the device relieves the stress of weakened blood vessel, although it may be used in a variety of body passageways to provide reinforcement of a supporting passageway or the like. The implantable intraluininai device is advantageously both radially and longitudinally flexible or bendable. When the tubular braid is elongated in the longitudinal direction, the diameter of the device is decreased so that it may be percutaneously implanted within a body passageway.
Once the device has been properly positioned within the body passageway, it is permitted to radially self-expand or self-deploy to come in intimate contact with the interior surface of the 0000w body passageway.
004 The hollow tubular braid may be formed from a number of natural and synthetic materials, including collagen, thermoplastics and metals. More specifically, thermoplastics 1 0 which are useful include polyesters, polypropylenes, polyethylenes, polyurethanes, or polytetrafluoroethylenes and combinations and mixtures thereof. Useful metallic substances include stainless steel, titanium and nickel-chromium alloys, among others. The hollow 0.80. tubular braid is formed to be radially self-expanding by heat-conditioning the thermoplastic or metal fibers from which the device is made at a sufficient time and temperature to effectuate memory. The braid is heat-conditioned in a radially expanded or longitudinally compressed position to provide the radially self-expanding feature of the device. For example, if the thermoplastic chosen for making a tubular braid is polyester, the tubular braid is preferably heat conditioned at a temperature from about 200'F to about 700*F for approximately five to thirty minutes and subsequently cooled while being maintained in a radially expanded position, thereby effectuating memory within the braided device.
PAOPERMAXD\89062OSPE.-5111/98 -6- The type of braid used to form the tubular device may be varied. More specifically, the intralumninal device may be formed from a simple three yarn tubular braid (twodimensional braid) or may be formed from a three-dimnensional braid. The braid may also include a yarn which is used to stiffen the tubular braided structure and provide a greater radially expanding force. The expanding radial force is preferably designed so that the intraluminal device will open up to be in intimate contact with the interior surface of the body passageway in which it is inserted and anchor itself thereto.
Generally, the fibers used to form the braid have a denier in the range of 20 to 500 denier, although deniers outside this range may have utility for specific applications. The force exerted by the device is non-rupturing, ie., sufficient to open the device without causing damage to the vessel wall. The braid may be formed with a braid angle between 150 and about 90' and preferably about 54.50 to about 750 with respect to the longitudinal axis of the braided structure. The braid angle is measured from the longitudinal axis of the braided 15 device.
Once inserted into the body passageway, the intraluminal device will be permitted to radially self-expand and substantially conform to the shape and inner surface of the body passageway. The intraluininal device need not be perfectly sized to the vessel or passageway 20 into which the device is inserted since the diameter of the device is infinitely variable in the ranges between its minimum diameter and its maximum diameter.
Advantageously, the radially self-expanding implantable intraluminal device once inserted and permitted to self-expand, may still be repositioned or realigned if not properly positioned within the lumen. In particular, by pulling on one end of the intraluminal device, the device will elongate in the longitudinal dircction causing a decrease in diameter of the device such that it is free to move within the vessel, thereby permitting the device to be easily repositioned. Once in the repositioned location and no longer longitudinally elongated, the device will once again radially self-expand to came into intimate contact with the inner of the lumen.
P:\OPER\AXD\1890620.SPE 5/11/98 -7- One method of producing a radially self-expanding implantable intraluininal device includes radially expanding a hollow tubular braid and subjecting the radially expanded braid to conditions of time and temperature sufficient to set the material in the radially expanded position. As a consequence of radial expansion, the device is shortened in length due to changes in the angle of the yarns with respect to the longitudinal axis. The braid is then permitted to cool while maintaining the braid in the radially expanded position. The heat source for heat conditioning the thermoplastic braid includes a convection oven, a heated mandrel, an infra-red light source or immersing the device in a hot liquid medium. The thermoplastic braid is preferably heated at a temperature of about 200'F to about 700'F for a time period of about five to thirty minutes. However, the heat parameters will vary depending upon the thermoplastic selected for forming the tubular braid. The heat a conditioning of the thermoplastic yarns of the braid provides the intraluminal device with memory to return the device to a radially expanded position following a reduction in diameter 15 due to longitudinal expansion so that the device may be intraluminally inserted into a body passageway.
4.
4 4 O: The intraluminal device may also include a means for attaching the device to the inner surface of the lumen to provide additional anchoring of the device. Such attaching means S 20 may include small hooks which are integrally formed on the outside or extraluminal surface of the device during the braiding process. Preferably, the hooks are integrally formed in at least one end of the device, although, depending upon the procedure being performed, both ends may include hooks. Anchoring means may also be added as a separate component if desired.
A preferred form of the intraluminal device, as well as other embodiments, features and advantages of this invention will be apparent from the following detailed description of illustrative embodiments thereof, which is to be read in connection with the accompanying drawings.
L d C L lIr I I I d iI .1 c~-r 7 I P:\OPER\AXD\ 890620.SPE-5/1/98 BRIEF DESCRIPTION OF THE DRAWINGS Fig.1 is a side elevational view of an intraluminal device shown in a radially expanded position; Fig.2 is a side elevational view of an intraluminal device shown in a longitudinally expanded, radially collapsed insertion position; Fig.3 is a side elevational view of an embodiment showing anchors positioned at one end of the intraluminal device; Fig.4 is a side perspective partial cutaway view of an implanted intraluminal device and a guide wire for repositioning the intraluminal device in accordance with an embodiment of the invention; Fig.5a is a cross-sectional view of a prior art stent-graft combination in an unexpanded 0 So0 a asi o o me D o a(: a" state; Fig.5b is a cross-sectional view of a prior art stent-graft combination in an expanded state within a lumen; and Fig.6 is a side elevational view of stent-graft combination.
SDETAILED DESCRIPTION OF THE INVENTION Figs.1 and 2 illustrate a radially self-expanding implantable intraluminal device formed from a hollow tubular thermoplastic braid. For purposes of describing the present invention, the terms "intraluminal device" and "radially self-expanding prosthesis" are interchangeably used in describing the methods, apparatus and structures used in accordance with the present invention. The intraluminal device may be used not only as an intraluminal vascular graft for supporting a diseased or damaged vessel, but its radially self-expanding capabilities give it a stent-like feature for expanding partially occluded segments of a blood vessel or body P:\OPER\AXD\1890620.SPE 5/11/98 -9passageway. Many other procedures which require a radially expandable prosthesis for a variety of body passageways are contemplated.
The intraluminal device especially be used in the following procedures: supportive graft placement within blocked blood vessels opened by transluminal recanalization, but which are likely to collapse in the absence of an internal support; a supporting graft structure following passage of a catheter through vessels occluded by inoperable cancers; supportive graft placement of narrowing of the esophagus, the intestine and the urethra; and supportive graft reinforcement of reopened and previously obstructed bile ducts. Accordingly, the terms "prosthesis" and "intraluminal device" encompass the foregoing usages within various body passageways or lumens. Further in this regard, the e term "body passageway" encompasses any duct within the human body, such as those 0 a 0 00 previously described, as well as any vein, artery or blood vessel within the human vascular 0 system.
00o Figures 5a and 5b illustrate a prior art graft-stent combination used to open constricted lumens as well as provide support for a weakened lumen. Referring to Figure 5a, an unexpanded stent 52 is illustrated positioned within a graft 54. The graft 54 is attached to the stent 52 by means of sutures 56. As illustrated in Figure 5b, this stent-graft combination may S 20 be inserted into a body lumen and once correctly positioned, the stent 52 is radially expanded to bring the stent-graft combination into contact with the inner wall of the lumen 58. The graft 54 is pressed against the inner wall of the lumen 58 by the expansion of the stent 52.
The diameter of the graft shown in Figure 5b was oversized and upon expansion by the stent, folds or creases 55 were formed in the graft because the graft could not be fully expanded.
The folds 55 may further weaken an already weakened lumen by placing excessive force on the lumen in the areas of contact. Accordingly, it would be advantageous to be able to properly size the stent-graft combination to form a more exact fit within the lumen.
Fig. illustrates a preferred embodiment of a self-expanding intraluminal device for ,3 use in accordance with the present invention. The device is in its radially expanded position.
1 if s..l P:\OPER\AXD\1890620.SPE- 5/11/98 The intraluminal device is in the form of a hollow tubular braid. The tubular braid may be any type of braid, for example either a simple, conventional braid, ie., a two-dimensional braid, or a three-dimensional braid. A braided structure is ideally suited for making tubular structures which can radially expand and contract, thereby forming a structure with an infinitely variable diameter within certain minimum and maximum values.
The tubular braid is preferably a simple, conventional two-dimensional braid formed from two sets of yarns spiralling in opposing directions about a longitudinal axis of the tube being formed. The braid angle (helix angle) of the tubular braid is the angle in relation to the t 10 longitudinal axis of the tube being formed and may vary from about 15° to 70°. The tubular braid is formed so that the yarn components 20 can scissor throigh severe angle changes *thereby altering the diameter of the tubular structure. In this regard, a tubular braid can be C formed which can be radially collapsed or longitudinally extended or elongated to form a K small diameter for implanting intraluminally into a body passageway. Following insertion 1 15 and positioning within the lumen, the device of the present invention will radially self-expand or longitudinally compress to form a relatively large diameter tube by causing the yarns to scissor to the larger diameter. This type of braided structure maintains structural integrity even when undergoing these geometric changes because the two opposing yarn systems are 0 interwoven. The yarns 20 are sufficiently spaced to allow them to move freely in place. As 20 can be seen comparing a radially collapsed tubular braid shown in Fig.2 with a radially i expanded tubular braid shown in Fig. 1, the space between the yarns will decrease as the f diameter increases.
For example, Fig. 1 illustrates a tubular braid in its radially expanded state 10 and Fig.2 illustrates the same tubular hr:iu in its radially collapsed state 30. In the radially collapsed state, the tubular braid may have a diameter of 6 millimeters whereas in the radially expanded state the diameter may be 18 millimeters. In this example, the diameter increase is three fold, and therefore, the ratio of the sine of the helix angle for the radially exp ,xded tubular braid should be three times that for the radially collapsed tubular braid. If the helix angle is 150 when the diameter of the tube is 6 millimeters, then the helix angle when the '>1 4 4' P:\OPER\AXD\1890620.SPE 5/I II9~ I P:\OPER\AXD\1890620.SPE- 5111198 I -11diameter is increased will be about 51'. This is mathematically proven by taking the sine of which is 0.2588, multiplying this value by three to yield 0.7764 and taking the inverse sine to arrive at a helix angle of about 51° and a diameter of 18mm.
Another characteristic of the tubular braided structure which makes it highly desirable j for use as an endovascular prosthesis is the flexibility of the structure. In a diseased or occluded blood vessel, the blood flow may be distorted or disturbed due to irregularities on the inner surface of .he blood vessel as well as the bends or curves of the vessel. The tubular braided structure is highly flexible and bendable both in the radial and longitudinal directions, can negotiate any curves or bends formed in the blood vessel and can conform to inner surface conditions found within the blood vessel. The tubular braid can be bent to angles approaching 1800 and still maintain an open lumen through the bend. The yarns 20 used to produce the flexible tubular braid preferably have a denier in the range of 20 to 500 denier whereby the smaller the yarn denier, the finer or thinner the yarn.
1 The selection of the yarn denier, type of yarn and braid angle and the number of carriers will also determine the porosity of the structure. These factors also dictate the S: strength and diameter of the device. The intraluminal device is most likely to be used to S support a weakened body passageway or maintain an opening in an occluded body I 20 passageway. Accordingly, the porosity of the device should be sufficient to allow ingrowth of surrounding tissue into the structure to encourage assimilation and anchorage of the device within the body passageway.
The yarns 20 used to form the tubular braid are preferably thermoplastics and metallic material. Suitable thermoplastic materials for forming the braid of the intraluminal device include but are not limited to polyester, polypropylene, polyethylene, polyurethane and polytetraflouroethylene. Suitable metallic materials for forming the braid of the intraluminal device inclue but are not limited to stainless steel, titanium and a nickel-chromium alloys, among others. A thermoplastic yar is preferably used so that, upon heat conditioning in the 30 O radially expanded state the braid becomes heat set with elastomeric memory and a natural lot- P:\OPER\AXD\1890620.SPE -5/11/98 -12tendency to return to this position. Thus, the braided device is radially self-expanding when restraining forces are removed. The braid may be formed on a mandrel having the diameter equal to the maximum expanded diameter of the braid. Alternatively, the tubular braid can be braided at a smaller diameter and heat set at a larger diameter. Thus, when the intralumival device is in an unstressed condition, the tubular braid will be in the radially expanded state. The heat conditioning of the thermoplastic braid effectuates memory. More specifically, the tubular braid contracts in diameter when placed under longitudinal stress, or i in other words, radially compresses. When the longitudinal stress is removed, tie tubular braid radially self-expands or returns to its original position or diameter, ie., approximately the diameter at which the device was heat conditioned or the diameter of the vessel in which 1it is contained. The tubular braid may also include a stiffening component, such as polymeric Sor metallic wires, to add a greater degree of stiffness, rigidity and resiliency to the structure.
The stiffening component could also provide the intraluminal device with a greater self- i" Q expanding or spring-like force. Additionally, the tubular braid may include axial yarns which 15 are braided into the structure to limit or control the amount of expansion of the device when in an unstressed state.
The method for making the intraluminal device includes forming a tubular braid from a yarn and preferably thermoplastic yarn. The tubular braid is preferably formed having a 20 small diameter and is thereafter placed in a radially expanded state for heat conditioning. A S.preferred method for heat conditioning includes placing the tubular braid on a mandrel so that S a".the biaid is radially expanded. The radially expanded thermoplastic braid is then heatconditioned or heat set at a sufficient time and temperature to effectuate memory. The heating time and temperature is dependent upon the yarn material chosen to form the braid.
Upon completion of the heating process, the tubular braid is cooled while maintaining the braid in the radially expanded position.
For example, if the thermoplastic chosen is polyester, the radially expanded tubular braid is preferably heat conditioned at a temperature between 300°F and 400'F for approximately ten to thirty minutes. The heating process may be accomplished by a variety a !i P:\OPER\AXD\1890620.SPE 511/98 -13of heating methods. The heating methods include but are not limited to the use of a convection oven, an infra-red light source, immersing the tubular braid in a hot liquid medium or by heating the mandrel on which the tubular braid is radially expanded.
Following heat conditioning, the tube is maintained in the radially expanded position and cooled to ambient temperature. An additional step in the procss optionally includes a cleaning or scouring process of the tubular braid prior to or following heat conditioning in order to remove any residuals which may be present on the tube from the braiding process.
i The cleaning is preferably performed using water or compatible solvents and cleaning agents.
The advantage of using the thermoplastic yarn and heat treating the tubular braid is that the intraluminal device f -rmed by this process is radially self-expanding. Thus, the intraluminal device does not require expansion in-vivo by a balloon catheter, such as the majority of mechanical stents available for use as an endovascular prosthesis. The SI intraluminal braided device is radially self-expanding and has the stent feature inherently 15 incorporated into the device.
The devices herein described may also be effectively used in combination with other prosthetic devices such as stents as illustrated in Fig.6. This embodiment of a stent-graft combination includes at least one stent 62, coupled to an intraluminal device 66. The stent I 20 62 is secured to the end of the intraluminal device 66 by means of hooks or sutures 68. The l.l C stent 62 serves to keep the lumen open and to enhance anchoring the intraluminal device 66 I in position. The intraluminal device 66 is radially self-expanding and, therefore radially expands along with the expansion of the stent. The intraluminal device 66 may be used to support a weakened or diseased vessel.
As previously mentioned, tubular endoprosthesis devices, ie., intraluminal grafts, have been used in combination with stents which were not self-expanding or radially adjustable.
Also these tubular endoprosthetic devices were fixed in diameter and were therefore not capable of being radially adjustable. Thus, this conventional combination use of stent and 30 tubular endoprosthetic device required special attention to the diameter size of the C P:\OPER\AXD\1890620.SPE 5/11/98 -14- 7i endoprosthesis such that it was large enough to allow for full expansion of the stent which was placed within it. Undersizing of the intraluminal graft would result in failure of the prosthesis to come into sufficient contact with the inside wall of the lumen to anchor the graft in place. The above described device advantageously allows the stent to be attached within the device such that expansion of the stent simultaneously controls the expansion of the graft, without the concerns addressed above.
The radially self-expanding intraluminal device may be deployed into a body passageway or lumen by conventional means. More specifically, the device may be inserted intraluminally by means of a catheter having a guide wire and an introducer sheath. The tubular braid is placed within the introducer sheath in a radially collapsed state. Once the sheath and tubular braid are properly positioned within the lumen, the introducer sheath is removed, and the tubular braid radially self-expands to come into intimate contact with the inner surface of the lumen. As previously described, the tubular braid is flexible and easily manipulated into proper position. Also, the intraluminal device has an infnitely variable and adjustable diameter in the ranges between the minimum and maximum diameter in the ranges between the minimum and maximum diameter of the device. Thus, the inner diameter of the lumen in which the device is inserted need not be exactly known or predetermined. The radial expansion of the braided intraluminal device will expand and conform to the shape and 20 contours of the lumen in which it is inserted without substantial wrinkles or creases typically formed by fixed diameter intraluminal devices. The braided tube is designed to radially selfexpand with a force sufficient enough to anchor the device within the lumen, without placing disruptive force on the walls of the lumen.
The intraluminal device also has the advantage of being repositionable within the lumen in which it is placed even after being permitted to radially self-expand. The prior art intraluminal prosthetic devices can not be repositioned once expanded without the use of surgery because these devices are not radially collapsible after being expanded. An intraluminal prosthesis may be misdeployed due to catheter malfunction or other difficulties 30 encountered during this type of procedure. Since the intraluminal device of the present i 1 :;ii PAOPER\AXD\I890620.SPE 5/11/98 7 invention is in the form of a tubular braid having a diameter which decreases when longitudinally elongated, the device may be repositioned by using a guide wire having grasping means such as a finger-like member at its distal end. Fig.4 is a side perspective partial cutaway view which illustrates a diseased blood vessel 40 showing an implanted intraluminal graft 10 and a guide wire 50 as previously described for repositioning the graft.
The guide wire preferably has at least one finger-like member 60 at its distal and perpendicular to the longitudinal axis of the guide wire. The finger is used to grasp the end of graft 10 closest to the direction in which the graft is to be moved. For example, in Fig.4, if the graft 10 is to be repositioned to the right of its present location, the finger will be used to grasp the end of the graft closest to the guide wire 50 as shown in Fig.4. When the graft is pulled by the guide wire 50, the braid yarns 20 will scissor and longitudinally expand (radially collapse), making it relatively easy to reposition the graft within the vessel.
F In an alternative embodiment, the intraluminal device may include a means for S 15 anchoring the device within the lumen in which it is inserted. An example of this embodiment is illustrated in Fig.3. The tubular braid 10 has hooks 70 integrally formed in 1: at least one end of the braid. Upon radial expansion, the hooks 70 slightly impinge the inner surface of the lumen or blood vessel to anchor the intraluminal device in position. In a blood i vessel, the hooks 70 might only be necessary at one end of the device since the flow of blood S: 20 will further serve to keep the graft in the expanded state, thereby providing sufficient contact with the lumen wall to stabilize against unwanted movement. In other body pasoageways, it may be advantageous to have hooks 70 at both ends to securely anchor the device in position.
In yet another embodiment, the ir. ralumrninal device may also be formed on a shaped mandrel in order to form a braid more closely resembling the length of lumen in which it is to be inserted. Additionally, in a braided structure, it is possible to form bifurcations, trifurcations or multiple tubular structures. This may be accomplished in a continuous process as the braided device is being formed, or by joining at least two braided tubes previously formed by sewing or other appropriate means for connecting the braided structures S 30 together to form a desired formation. Thus, a braided structure is more versatile in design P:\OPER\AXD\l890620.SPE /l 1/98 -16than conventional stents and grafts.
Thus, while there have been disclosed what are presently believed to be the preferred embodiments of the present invention, other and further manifestations of the invention will become apparent to those skilled in the art. It is intended to claim all such changes and modifications which come within the true score and spirit of the present invention.
Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", will be understood to imply the inclusion of a stated integer or group of integers or steps but not I: the exclusion of any other integer or group of integers or steps.
i p *o t o ot *0