A stent graft having improved attachment within a body vessel

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DESCRIPTION

Stent graft with foldable graft member.

Field of the invention

The invention relates to percutaneously delivered stent grafts for repairing abdominal aortic aneurysms.

Background of the invention

An abdominal aortic aneurysm consists of a sac caused by an abdominal dilation of the wall of the aorta, a main artery in the body, as it passes through the abdomen. The abdomen is that portion of the body that extends between the thorax and the pelvis. It contains a cavity, known as the abdominal cavity, separated from the thoracic cavity by the diaphragm, and lined with a membrane, the peritoneum. The aorta is the main conduit, or artery, from which the systemic arterial system extends. It originates in the left ventricle of the heart, passes upward, curves in on itself, and passes downward through the chest and through the abdomen to approximately the level of the fourth lumbar vertebra, where it divides into the two common iliac arteries. .

The aneurysm frequently occurs in the infrarenal portion of the diseased aorta, for example, below the kidneys. When left untreated, the aneurysm could eventually cause the sac to rupture with a resulting fatal hemorrhage in a very short time. The high mortality associated with rupture has led to the current state of the art and to trans-abdominal surgical repair of abdominal aortic aneurysm. Surgery that includes the abdominal wall, however, is an important compromise with high associated risks. There is considerable mortality and morbidity associated with the magnitude of the surgical intervention, which in essence includes replacing the diseased and aneurysmal segment of the blood vessel with a prosthetic device that typically consists of a synthetic tube, or graft, normally manufactured with DACRON®, TEFLOLN ®, CORteX® or other suitable material.

The surgical procedure requires exposing the aorta through an abdominal incision that can extend from the rib cage to the pubis. The aorta must be squeezed transversely both above and below the aneurysm so that the aneurysm can then be opened, and the thrombus, or blood clot, and arteriosclerotic debris removed. The small arterial branches that start from the back wall of the aorta are ligated. The DACRON® tube, or graft, approximately the same size as the normal aorta, is sutured in place, thereby replacing the aneurysm. Blood flow through the graft is then restored. It is necessary to move the intestine in order to reach the back of the abdomen prior to ligation of the aorta.

If surgery is performed before ruptured abdominal aortic aneurysm, the survival rate of treated patients is significantly higher than if surgery is performed after ruptured aneurysms, although the mortality rate is still high. . Although abdominal aortic aneurysms can be detected from routine examinations, the patient may not experience any pain from the condition. Thus, if the patient is not undergoing routine examinations, the aneurysm may progress to the rupture phase.

The disadvantages associated with conventional prior art surgery, in addition to the high mortality rate, are: the long recovery period associated with the large surgical exposure in such open procedures; difficulties in suturing the graft, or tube, in the aorta; the loss of existing thrombosis to support and strengthen the graft; the inappropriateness of surgery for many patients with abdominal aortic aneurysms; and the problems associated with performing surgery on an emergency basis after the aneurysm has ruptured. In terms of recovery, a patient can expect to need between 1 to 2 weeks in hospital after surgery, most of which is spent in the intensive care unit, and a convalescence period at home of 2 to 3 months, particularly if the patient has another disease such as heart, lung, liver and / or kidney disease, in which case the hospital stay is also lengthened. Since the graft must be secured to, or sutured into, the remaining portion of the aorta, it is often difficult to carry out the suturing step due to thrombosis present in the remaining portion of the aorta, as that portion of the wall of the aorta can be brittle, or easily crumbly.

Since the thrombosis is completely removed in prior art surgery, the new graft does not have the benefit of the previously existing thrombosis in it, which could be used to support and reinforce the graft, should the graft be able to be inserted into the existing thrombosis. Since many patients who have abdominal aortic aneurysm have other chronic diseases, such as heart, lung, liver and / or kidney disease, associated with the fact that many of these patients are older, these patients are not ideal candidates. for that surgery, considered a major surgery. Such patients have difficulty surviving the operation. Finally, once the aneurysm has ruptured, it is difficult to perform conventional surgery on the facilitated bases, due to the extent of the surgery.

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Consequently, the prior art teaches various procedures and apparatus for repairing an abdominal aortic aneurysm, which is estimated to reduce the morbidity and mortality ratio by not requiring any abdominal incision or general anesthesia, nor requiring suturing of the graft in the aortic wall. remaining, and allowing the existing aortic wall and its thrombosis to be preserved to reinforce and support the aortic graft. An example of this type of procedure and apparatus is provided by US Patent Nos. 5,316,023, issued to Palmaz et al. On May 31, 1994; 5,360,443 issued to Barone et al. On November 1, 1994; 5,578,071 issued to Parodi on November 26, 1996; and 5,591,229 issued to Parodi on January 7, 1997.

Devices such as that shown in the Barone patent referenced above utilize an improved procedure to repair an abdominal aortic aneurysm in an aorta having two iliac arteries associated with it. The device includes first and second tubes, preferably made from a variety of materials such as DACRON® and other polyester materials, TEFLON® (polytetrafluoroethylene), TEFLON®-coated DACRON®, porous polyurethane, silicone, expanded polytetrafluoroethylene. , and expanded polyurethane. It is preferred that all of the above materials are porous to allow an intimate layer to form on the tubes. Each of the tubes is connected to expandable and deformable tubular members, or stents. These stents can be similar in structure to those described in US Pat. 4,733,665, issued March 29, 1988; in US Patent No. 4,739,762, issued April 26, 1988, and in US Patent No. 4,776,337, issued October 11, 1988, all of these prior patents being in the name of Julio C. Palmaz. Each of the tube / stent structures are then disposed at the end of a balloon catheter. Each of both tubes is inserted into the same femoral artery, or one of the tubes is inserted into a patient's femoral artery and the other tube is inserted into another patient's femoral artery. The tubes are then delivered intraluminally to the aorta, thereby placing at least a portion of each tube within the abdominal aortic aneurysm. The balloons at the distal ends of the catheters are then expanded, to expand and deform the tubular members, to force the tubular members radially outward into contact with the aorta and each other. This fixes the tubular members and at least a portion of each tube within the aorta, whereby the tubes provide a bilateral passage for fluid through the abdominal aortic aneurysm.

Although the aforementioned devices might appear to work well, there is a desire to improve the device. More particularly, there was a need to ensure that most of the blood flowing through the abdomen flows through the bilateral fluid passages and not around them, which could cause further damage. The stent precursor gasket described in the European patent application EP 0947179 transferred in accordance with the law, filed on March 29, 1999, the European patent application EP 1000590 (A1), filed on November 8, 1999, and the application European Patent EP 108 6665, limit the amount of blood that could be lost around bilateral fluid passages, and in the aneurysm. The precursor stent joint is positioned within the infrarenal neck, between an abdominal aortic aneurysm and the renal arteries, of a patient, to help repair the abdominal aortic aneurysm. The stent is designed to be attached to bilateral grafts to direct blood flow. The graft has a distal end for positioning distal to the aneurysm, and a proximal end for positioning proximal to the aneurysm. The precursor stent joint includes a substantially cylindrical expandable member, having a proximal end, a distal end, and an interior. The stent seal further includes a compressible seal member positioned within and attached to the expandable member. The compressible member is substantially impermeable to blood when in a compressed state and is attached to the graft. In this way, the attached device can direct blood flow through the graft, the joint member substantially preventing blood from flowing through the aneurysm.

Although the devices described above constitute great improvements over the prior art, there remains a need for improvements. There is a desire to have a device that is better for attaching graft material to grafts used in the devices described above. There is a desire for an improved stent seal member for better fixation of the stent seal member to the aortic wall. There is a desire for a mechanism that ensures that the stent joint member does not prematurely deploy. There is a desire to refine the design of stent grafts for better performance. Lastly, there is a desire to improve the grafts on the stent grafts themselves to make them perform better during deployment. EP-A-0 666 066 describes a stent graft for insertion into a body vessel of a patient. The stent graft comprises a proximal stent, a distal stent, and a graft member attached thereto. The graft member includes proximal and distal sections that overlap the proximal and distal stents, and that have a plurality of longitudinal folds disposed therein. Between the proximal and distal graft sections, there is a central section that includes a plurality of radial folds. The invention described below provides such an improved device.

Summary of the invention

In accordance with the present invention, there is provided a stent graft for insertion into a vessel in the body of a patient, the stent graft including a radially expandable, substantially cylindrical single hollow stent having a body, two open ends and a longitudinal axis between the two. The stent body is made from a plurality of interconnected struts. The stent graft further includes a graft member attached to the single stent body, wherein the graft member has a plurality of substantially longitudinally directed folds disposed thereon and a plurality of radially oriented fold interruptions, arranged on it. The graft member and the single stent are substantially the same length.

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Brief description of the drawings

The foregoing and other aspects of the present invention may be better appreciated with reference to the detailed description of the invention together with the accompanying drawings, in which:

Figure 1 is a perspective view of a precursor stent (shown without a gasket, in an expanded state);

Figure 2 is a view similar to Figure 1, but including a gasket member;

Figure 3 is a cross-sectional view of the precursor stent of Figure 2, taken along section line 3-3 of Figure 2;

Figure 4 is a side elevation view of the endograft stent prior to application of graft material, and in an expanded state;

Figure 5 is a side elevation view of a longitudinally folded graft, to be used in conjunction with the stent of Figure 4, in which the pleats are discontinuous;

Figure 6 is a partial side elevation view of another embodiment of the graft, in which the longitudinal folds are interrupted by circumferential folds;

Figure 7 is an end elevational view of the graft, taken along line 7-7 of Figure 5, with the dashed line embodiment depicting the graft in a compressed state;

Figure 8 is a side elevational view of a complete stent-graft assembly, shown in the deployed state;

Figure 9 is an enlarged partial plan view of a fixation tab at the cranial end of the stent as shown in the area of ​​Figure 4 circled;

Figure 10 is an exploded partial cross-sectional view of the fixation tab taken along line 10-10 of Figure 9, and includes a staple and a portion of the graft material prior to fixation. of the graft in the stent;

Figure 11 is a partial cross-sectional view of the clamping means after crimping the staple;

Figure 12 is an enlarged partial plan view of an attachment node to the caudal end of the stent, as shown in the area of ​​Figure 4 circled;

Figure 13 is an exploded partial cross-sectional view of the clamping node taken along section line 13-13 of Figure 12, and including a staple and a portion of the graft material prior to placement. fixation of the graft in the stent;

Figure 14 is a partial cross-sectional view of the clamping means after crimping the staple;

Figure 15 is a partial, exploded perspective view of the caudal end of a stent, or endograft joint, and of a portion of a delivery system, after release from the delivery system;

Figures 16, 17 and 18 are sequential, schematic perspective views showing the procedure for positioning and deployment of stent grafts, or endo-grafts, after the precursor stent has already been deployed;

Figure 19 is an elevational view of a fully deployed abdominal aortic repair system;

Figure 20 is a top plan view of the precursor stent as viewed along line of sight 20-20 of Figure 19;

Figure 21 is a micro-photograph of gasket material prior to substantial internal cell growth, taken along section line 21-21 of Figure 3;

Figure 22 is a micro-photograph of the gasket material after substantial internal cell growth, or biofusion, has taken place, taken along line 22-22 of Figure 19;

Figure 23 is an elevational view of a delivery system for a stent joint in which the delivery system is inserted into an abdominal aortic aneurysm;

Figure 24 is a view similar to Figure 23, but showing the stent gasket partially deployed from its delivery system, and

Figure 25 is a view similar to Figure 24, but showing the stent joint fully deployed from its delivery system.

Detailed description of the invention

A preferred use of the present invention is in treating abdominal aortic aneurysms. A better understanding of the present device and its use in the treatment of abdominal aortic aneurysms will be gained from reading the description that follows, in conjunction with the references incorporated above. Additionally, the terms cranial and distal will refer to the direction towards the head of the patient, and the terms caudal or proximal will refer to the direction from the head of the patient.

Referring now to the drawings, in which like numbers indicate the same element throughout the views, a precursor stent 10 is shown in Figure 1, shown in Figure 1. As will be discussed below, stent 10 is to be deployed within the infrarenal neck, between an abdominal aortic aneurysm and the renal arteries of a patient, to help repair the abdominal aortic aneurysm. The stent has been designed to be coupled with one or more stent grafts to direct blood flow through the aneurysm. The stent includes a substantially cylindrical self-expanding member 12, made from a plurality of interconnected struts. Member 12 has two open ends, a proximal end 14, a distal end 16, and a longitudinal axis extending between the two, and an interior 18. The precursor stent further includes at least two, preferably 8 as shown in Figure 1, spaced longitudinal legs 20, having proximal and distal ends 24 and 26, respectively. Preferably, there is a leg extending from each vertex 11 of the diamonds 13 (such diamonds being formed by the struts). The distal ends 26 of the legs are attached to the proximal end 14 of the member 12, the legs extending proximally out of the member. At least one, but preferably each, of the legs includes a flange 28 adjacent its proximal end which, as will be described in greater detail below, allows the stent to be retrieved into its delivery system after delivery. full or partial deployment of member 12 so that it can be rotated or otherwise repositioned for proper alignment.

The self-expanding stents described herein are preferably manufactured from super-elastic Nickel-Titanium (Nitinol) alloys. Descriptions of medical devices using such alloys can be found in US Patent 4,665,906 issued to Jervis on May 19, 1987, and in European Patent Application EP 0928606 filed on January 8, 1999. Stent 10 is preferably laser cut from a Nickel Titanium Alloy tubular piece, and then treated to exhibit superelastic properties at body temperature. Stent 10 is shown in the Figures as a diamond patterned stent, having approximately 8 diamonds, and when the stent is fully expanded the diamonds will have 45-55 degree angles at its distal and proximal ends. However, the stent 10 can take on many different designs or configurations.

In one embodiment of precursor stent 10, shown in most of the Figures but removed from the Figure for clarity, the precursor stent 10 further includes a gasket member 30 (thereby forming a stent gasket or stent graft). ). This feature can be better understood by referring to Figures 2 and 3. As seen in those Figures, the precursor stent 10 further includes a gasket member 30. The joint member 30 surrounds the member 12 and can be located along the inside of the member 12, the outside of the member 12, or both. The gasket member helps prevent any attempts for blood to flow around the stent grafts, described below, after they have been inserted (as shown in Figure 19), and to flow around the stent itself. precursor. In this embodiment, the joint member 30 consists of a compressible member located along the interior and exterior of the expandable member 12.

The joint member 30 can be made from any number of materials known to those skilled in the art. Preferably, the gasket member 30 is made of open-cell polyurethane foam, although other flexible foams, such as polyethylene, polytetrafluoroethylene, could nevertheless be used, and various other polymeric materials that are woven or woven may also be used to provide a structure. flexible such as Dacron, polyurethane, polypropylene, polyetrafluoroethylene. Preferably, the polyurethane foam has a cell size of 20-39 pores per cm (50-100 pores per inch), and the density of the foam is 24-56 kg / m³(1.5-3.5 pounds per cubic foot). Foams that have these qualities absorb blood like sponges, contributing to stagnation of blood that leads to thrombosis. Additionally, it provides a lattice for cellular infiltration, and eventually the incorporation of scaffolds for the tissue. This helps to better anchor the device within the body, thereby preventing migration of the stent. An example of such a foam is shown in the photograph in Figure 21. Figure 21 shows an electron microscope scan of an open cell polyurethane foam having approximately 200-500 pores per micron.

This ability of the arterial wall tissue to incorporate the open pore foam structure has been referred to by the assignee as "Biofusion". This effect of tissue incorporation can be better appreciated with reference to photographs 21 and 22. Figure 22 shows histological photographs of infiltration and healing of connective tissue in the joint member 30 after 1 month of having implanted a device in a vessel. target. This ability of the tissue to cure in the foam creates a long-term stable biological interface that, after about six weeks after implantation, cannot be separated from the tissue without tearing the foam material. The “Biofusion” effect has many advantages. This has the potential to bypass subsequent endo-losses by preventing unorganized clot zones from being displaced or re-channeled. It is also believed that "Biofusion" creates a necklace.

ES 2 298 201 T3 of connective tissue around the joint that could prevent the aortic neck from dilating over time. Limiting neck dilation avoids endo-loss and implant migration trajectories that could be caused by insufficient coupling with the aorta. The use of such foams described above on stent grafts is not limited to the repair of an abdominal aortic aneurysm, but could be applied in many applications such as other aneurysm repair and malformation and occlusion of vessels. .

The foams described above are preferably highly compressible, in order to maintain the low wavy profile for better delivery. Furthermore, it is preferred that the seal member is substantially impermeable to the flow of blood, at least when in a partially compressed state. When used in the present invention, materials that are substantially impervious to the flow of blood include materials that become substantially impervious to the flow of blood after being saturated with blood. When the stent tubes and graft members, which are described below, are inserted and expanded within the gasket 30, the gasket 30 will be compressed. In that state, the gasket will be substantially impermeable to blood so that blood is prevented from flowing through the interior 18 of the member 12 and into the aneurysm. The joint 30 may be attached to the expandable member 12 by any number of means including a polyurethane glue, a plurality of conventional polypropylene sutures, DACRON^®, or any other suitable material attached to it. Other methods of attaching gasket 30 to the expandable member include adhesives, ultrasonic welding, mechanical interference coupling, and staples.

As seen from Figure 2, stent 10 preferably includes a number of radiopaque markers. As shown, the markers 15 are coils of radiopaque metal, wound around the struts of the stent. The markers are positioned along the stent so that the clinician can better understand the exact position of the stent during deployment when viewed under fluoroscopy. Markers 15 are preferably made from 2.54 pm (0.010 ") diameter tantalum wire (Ta) wrapped tightly around the struts. Three members are used: two near the distal end of the device, and one proximal to it. The two distals are 180 ° apart, and the proximal one is evenly spaced between the two distals when viewed in rotation when the top two are as far apart as possible. The proximal marker then assists in proper rotational positioning of the device. Specifically, one of the distal markers is 5mm in length and is adjacent to the gasket opening 34; the other is 2mm long and is adjacent to hole 36. Since hole 36 should be positioned adjacent to the right side of the aneurysm, as shown in Figure 19, the small distal marker should be placed on the right side; the proximal marker (also 2 mm long) should appear fluoroscopically in an intermediate position between the two upper markers.

As seen in Figures 2 and 3, the precursor stent includes an occlusive member 32 attached to member 12. The occlusive member covers at least a portion of the interior of the expandable member. The occlusive member covers the interior of member 12 such that a lumen 5 of the expandable member providing the passage from its proximal to distal end 4 is at least partially blocked. Occlusive member 32 further includes two openings 34 and 36 extending therethrough. The aperture 34 is relatively small and has been designed to receive a guidewire, wherein the guidewire helps to hold the stent 10 in place. Opening 36 is relatively large, and has been designed to receive another guidewire loaded with a stent graft proximal thereto. As will be explained in the following, the occlusive member helps to secure the proper side by lateral placement of the two stent grafts.

The precursor stent 10 acts as a temporary scaffold for the joint member within the body, until the stent grafts are deployed (see Figure 19). Shown in Figure 4 is a preferred embodiment of a stent 40 for use in a stent graft in accordance with the present invention. Stent 40 is made of a plurality of interconnected struts 44, and has an inner surface 41 and an outer surface 43 (shown in Figure 15). Figure 4 shows stent 40 in its fully deployed, non-corrugated state. As those skilled in the art will appreciate, stent 40 must be curved to a smaller diameter prior to insertion into a patient. Stent 40 is preferably made of super-elastic Nitinol, and has sufficient outward force to remain within the body, without the use of precursor stent 10. Stent 40 is preferably made from a single Nitinol tube, having the following characteristics, laser cut therein. Stent 40 has a number of rings 42 comprising a number of struts 44 that form a diamond-shaped configuration, with each ring preferably having 9 diamonds. Stent 40 further includes a number of sinusoidal rings 50 for connection of adjacent rings to one another. The sinusoidal rings are made from a number of alternate struts 52, where each ring preferably has 54 struts. As will be explained in detail below, in connection with the discussion of Figures 4-9, the stent 40 includes a distal clamping means 54 and a proximal clamping means 56.

Stent 40 has a proximal ring 48 and a distal ring 46, also referred to as anchors. The proximal ring is flared, and is exposed once the graft has been attached to it. The diamond design for the anchors, as well as for the other rings, gives the rings radial and longitudinal rigidity. Longitudinal strength provides better mechanical fixation of stent 40 to a graft (described below). Radial resistance provides distal ring 46 with better clamping and sealing with stent gasket 10, and provides proximal ring 48 with better fixation and sealing with the arterial wall. In a preferred embodiment, the proximal and distal rings have greater radial and longitudinal strength than the rings between the two. This creates a stent graft that has stiff ends for anchoring, but a more flexible body for navigation through the vasculature. The stiffer ends can be made by changing the dimensions of the struts on the rings

ES 2 298 201 T3 extreme, or by varying the heat treatment of the extreme rings during manufacture. The rings allow the stent to bend more easily, and generally provide more flexibility when the stent is being delivered through a tortuous vessel. When a non-elastic graft is attached to stent 40, the strength of the diamond rings provides scaffolding to any graft that kinks into the blood flow lumen, while maintaining a tight kink radius.

As discussed above, stent 40 has a graft member attached thereto. The graft member covers at least a portion of the interior or exterior of stent 40, and more preferably substantially covers the entire exterior of stent 40. An embodiment of a tubular graft 60 for use with the present invention. The graft member 60 can be made from any number of materials known to those skilled in the art, including woven polyester, Dacron (Trade Mark), Teflon (Trade Mark), or polyurethane. Graft 60 has a proximal end 64, a distal end 62, and a longitudinal axis 66 extending between the two. As seen in Figure 5, graft 60 has a plurality of longitudinal folds 68 that extend along its surface, and are generally parallel to its longitudinal axis 66. As seen from Figure 7, when graft 60 is folded around its center, as much as it would be when delivered to a patient, the graft folds are together in the form of a series of radially oriented regular folds that are efficiently crowd each other, minimizing roughness and other geometric irregularities. Upon subsequent expansion, the graft 60 assumes its natural cylindrical shape, and the folds or folds open evenly and symmetrically.

The pleats provide a more uniform crimp of graft 60, which helps crimp the assembled stent graft (stent 40 attached to graft 60, as will be discussed later), in a relatively low profile delivery system, and provides its deployment in a controlled and uniform manner. In addition, the folds 68 help to facilitate the fabrication of the stent graft, because they indicate the direction parallel to the longitudinal axis, allowing the graft to be attached to the stent along these lines, and thereby preventing accidental twisting of the stent. graft with respect to the stent after fixation. The force required to push the stent-graft out of the delivery system can also be reduced, because only the pleated edges of the graft can frictionally contact the inner surface of the delivery system. An additional advantage of the pleats is that blood tends to coagulate generally uniformly in the passageways of the pleats, opposing the formation of an asymmetric or large clot on the surface of the stent, thereby reducing the risk of embolism.

In a preferred embodiment, the depth of the pleats 68 is in the range of 1.52 mm (0.06 inches) to 1.78 mm (0.07 inches) for a graft having an internal crimp diameter of 2 .03 mm (0.08 inches), and an outer diameter of crimp that is in the range of 3.32 mm (0.131 inches) to 3.94 mm (0.155 inches). This combination of fold depth and internal and external diameters results in fold frequencies that generally avoid the existence of an excessive number of radial graft flaps throughout the diameter range of the device.

As best seen in Figure 6, graft 60 includes a plurality of radially oriented fold interruptions 70. The fold interruptions are substantially circular and are oriented perpendicular to the longitudinal axis 66. While the aforementioned pleats 68 provide uniform undulation of graft 60, they may tend to increase the propensity for kinking because they run perpendicular to the natural folding tendencies of the graft when curved along its axis. The fold interruptions 70 allow the graft to curve better at selected points. This design provides a graft that has good crimpability and improved kink resistance.

Figure 9 shows a top view of a distal clamping means 54 of stent 40. The distal ring 46 of stent 40 has a plurality of attachment tabs 82 extending therefrom, which are formed by joining two struts together. 44 (a) and 44 (b). Fixation means 54 comprises two apertures 84 (first aperture) and 86 (second aperture) extending therethrough. As seen in Figure 10, graft 60 also preferably includes two openings 74 and 76 (which may be created initially during the fixation process), which are coextensive with openings 84 and 86 when graft 60 is placed over stent 40 for fixation. Finally, the stent-graft 80 includes a staple 90 having a crown 92 and clamping legs 94 (first leg) and 96 (second leg) extending therefrom. The clamping leg 96 extends through the openings 76, and then through the opening 86. Simultaneously, the leg 94 curves around the notch 85, but does not penetrate the graft like the leg 96. Thereafter, the legs Fixation legs 94 and 96 curve back through openings 84 and 74, and toward crown 92, in order to secure the distal end of the graft to the distal end of the stent as shown in Figure 11. Legs 94 and 96 contact crown 92 after clamping. Preferably, there are six staples at the distal end.

Figure 12 shows a view of the proximal fastener 56 of the stent 40. The proximal ring 48 of the stent 40 has a plurality of members 110 that occur at the junction of four struts 44 (c) -44 (f). The fastening means 56 comprises three openings 112 (first opening), 114 (intermediate opening) and 116 (second opening) extending therethrough. As seen in Figure 13, graft 60 also preferably includes three openings 121, 123, and 125 (which may initially be made during the clamping process by punching through with a staple), which are co-extensive with the openings. 112, 114 and 116 when graft 60 is disposed on stent 40 for attachment. Finally, the stent-graft 80 includes a staple 120 having a crown 122 and legs 124 (first leg) and 126 (second leg) extending therefrom. Legs 124 and 126 extend through openings 112 and

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116, and then through apertures 121 and 125, respectively. Legs 124 and 126 are then bent back through openings 124 and 114, and into crown 122, in order to hold the proximal end of the graft at the proximal end of the stent as shown in Figure 14. Legs 124 and 126 contact crown 122 upon clamping. Preferably, there are three staples at the proximal end.

The foregoing staple opening design has many advantages for attaching a stent to a graft. Since the legs of the staple curve around and embed within a cavity or the like, the risk of puncturing an inflation balloon is minimized. In addition, it is estimated that the structural integrity of the stent-graft is increased because these staples will be able to more securely hold the graft with the stent compared to prior art designs that use sutures or adhesives to secure the graft to the stent. Staples 90 and 120 can be made from any number of materials known in the art, including tantalum alloys, platinum alloys, or stainless steel, such as 316 LVM stainless steel. The staples may take other shapes and configurations, and may be coated for lubricity purposes. Making the staples from a radiopaque material helps the physician to precisely deploy the device.

Another feature of stent-graft 80 can be better understood with reference to its delivery apparatus 130 shown in Figure 15. Apparatus 130 is very similar to another self-expanding delivery apparatus described in the references identified above. Apparatus 130 includes an outer sheath 132 that is essentially an elongated tubular member, similar to ordinary guiding catheters well known to those of skill in the art. An example of a particularly preferred outer sleeve is described in US Pat. 6,019,778 transferred pursuant to law, granted Feb. 1, 2000. Sheath 132 has a distal end 134 and a proximal end (not shown). The apparatus 130 also includes an internal shaft 140 located coaxially within the external sleeve 132 prior to deployment. The inner shaft has a distal end 142 and a proximal end (not shown). The distal end 142 of the shaft has at least two grooves 144 disposed therein. Stent 40 preferably has a number of flanges 41 disposed at its proximal end. The tabs of the stent are disposed within the grooves of the inner shaft, thereby releasably holding the stent with the inner shaft. The delivery system for the precursor stent 10 is also similar, having an outer sheath and an internal shaft, in which the shaft has grooves to receive flanges 28 from the precursor stent 10.

The advantages of the flanges 41 of the stent 40 and of the flanges 28 of the precursor stent 10 and of the grooves of the internal shafts of their delivery system, are that these can allow the partial deployment of the stents and their re-capture in inside the delivery apparatus in case the clinician is not satisfied with the position of the stent. The present invention allows the clinician to partially deploy one of the stents (10 or 80) while the tabs remain within the sheath. The flange and groove combination allows the clinician to “pull” the stent back toward the delivery device in the event that placement is not optimal.

The advantages of the flanges 28 of the stent 10 and the internal shaft grooves of its delivery system can best be described with reference to Figures 23-25. Figure 23 shows delivery apparatus 300 for a stent joint 10. Apparatus 300 is very similar to other self-expanding delivery apparatus described in the above incorporated references. Apparatus 300 includes an outer sheath 332 that is essentially an elongated tubular member, similar to ordinary guiding catheters that are well known to those of skill in the art. An example of a particularly preferred outer sleeve is described in US Pat. 6,019,778 transferred in accordance with the law, granted on February 1, 2000. The apparatus 300 also includes an internal shaft 340 located coaxially within the external sleeve 332 prior to deployment. The inner sheath 334 includes a number of slots 334. As seen in Figure 24, this arrangement allows for partial deployment of stent 10 and its re-capture within the delivery apparatus if the clinician is not satisfied with the initial position. of the stent. The present invention allows the clinician to partially deploy stent 10 while the tabs remain within the sheath. The flange and groove combination allows the clinician to "pull" the stent back toward the delivery device in the event that placement is not optimal.

In order to prevent the physician from fully deploying the stent 10 prematurely, a releasable stop 350 is preferably disposed on the inner shaft. The stop could be a ring having a diameter greater than that of the sheath, such that as the sheath is pulled proximally along the internal axis, the sheath strikes against the stop, and prevents full deployment of the stent 10 in its entirety. whole. The stopper is preferably releasably attached to the inner member, so that it can be released from engagement with the inner shaft, to allow the outer member to slide back enough to fully deploy the stent 10 in its entirety on the inside. of the body.

Figures 16-18 generally show how the above-described invention unfolds within the body. Prior to what is shown in Figure 16, the physician should first insert the precursor stent 10, with the joint member attached thereto, into the body with the aid of a guide wire 200 that remains in place. the body after deployment. The stent joint is delivered through one of the patient's femoral arteries, and into the first iliac artery 1, and is deployed into the infra-renal neck 3. Next, the delivery device for the precursor stent is removed, without removing the guidewire 200, and another guidewire 202 is inserted through the other femoral artery and into the other iliac artery 2. Since the size of the opening 36 of the occlusive member 32 is relatively large, the physician can only maneuver the guidewire 202 through it. Next, the stent-graft delivery apparatuses 132 (a) and 132 (b) are inserted into femoral arteries 1 and 2 by sliding them over guide wires 200 and 202, and delivering them precisely

ES 2 298 201 T3 to the desired location. Next, both stent grafts 80 (a) and 80 (b) are deployed separately, or simultaneously, into the body. Finally, the distal ends of the grafts reside level with each other, just below the renal arteries, and some distance above the distal end of the stent joint. The stent graft bodies pass through the stent joint and through the aneurysm sac.

Upon proper delivery, the precursor stent 10 and stent grafts 80 (a) and 80 (b) should appear as they do in Figure 19. The precursor stent 10, along with its attached joint member 30, are firmly secured. inside the neck 300 infra-renal. The outward force of the stent grafts 80 on the precursor stent 10 helps to secure the device within the body. The proximal ends of the stent grafts are firmly attached to the 1st and 2nd iliac arteries. Next, blood will flow from abdominal aorta 302 downward to and through stent grafts 80 (1) and 80 (b) and into iliac arteries 1 and 2, thereby bypassing aneurysm sac 304. If all components are precisely positioned, the distal end of the device should appear as it does in Figure 20.

In order to prevent the clinician from fully deploying the stent 10 prematurely, a releasable stop is preferably provided on the inner shaft. The stop could consist of a ring having a diameter greater than the outer member, such that as the outer member is pulled proximally along the inner axis, it collides with the stop, and prevents full deployment of the stent 10 as a whole. . The stopper is preferably releasably attached to the inner member, by means of threads, by snap coupling, or the like, so that it can be released from engagement with the inner shaft to allow the outer member to slide rearward. enough to fully deploy the stent 10 in its entirety within the body.

Although particular embodiments of the present invention have been shown and described, modifications may be made to the device without departing from the scope of the present invention. The terms used in the description of the invention are used in their descriptive sense and not in limiting terms.