Endovascular aneurysm repair systemThis application claims priority to provisional application No. 60/333,937 in esthetic countries filed on day 11, month 28, 2001.
Technical Field
The present invention relates generally to the attachment of vascular prostheses to natural blood vessels, and in particular to methods and apparatus systems for repairing diseased and/or damaged vessel segments.
Technical Field
Weakening of the vessel wall by injury or morbidity can result in expansion of the vessel and formation of a hemangioma. If left untreated, hemangiomas can grow in size and will eventually rupture.
For example, aortic aneurysms occur primarily in the abdominal artery region, generally in the infrarenal region between the renal arteries and the aortic bifurcation. Aneurysms may also occur in the thoracic region between the aortic arch and the renal arteries. Rupture of an aortic aneurysm can cause major bleeding and is highly lethal.
Open surgical replacement of diseased or damaged vessel segments can reduce the risk of vessel rupture. In this procedure, a diseased or damaged vessel segment is excised and a prosthetic graft, either fabricated in a straight or weighted configuration, is installed and then permanently attached and sealed to the end of the native vessel with sutures. These surgical prosthetic grafts are generally unsupported woven tubes and are typically made of polymer, ePTFE, or other suitable material. The grafts are longitudinally unsupported so that they can accommodate changes in the morphology of hemangiomas and native vessels. However, these procedures require large surgical incisions and are high in morbidity and mortality. In addition, many patients are not suitable for this type of major surgery due to other comorbidities.
Endovascular aneurysm repair has been introduced to overcome the problems associated with open surgical repair. Aneurysms are bridged by vascular prostheses placed endoluminally. Typically, these aneurysm prosthetic grafts are delivered deflated via a catheter through the femoral artery. These grafts are typically designed with a fibrous material attached to a metallic stent (stent) structure that is expanded or expanded to contact the inner diameter of the vessel. Unlike open surgical aneurysm repair, intraluminal deployment of a graft does not suture to the native vessel, but relies on barbs extending from the stent that penetrate into the native vessel during deployment, or the radial expansion force of the stent itself to hold the graft in place. These graft attachment means do not provide the same attachment strength when compared to sutures, and may damage the native vessel when deployed.
There is therefore a need for an endovascular aneurysm repair system that firstly provides a prosthetic graft that can adapt to the morphological changes of the aneurysm and can be deployed without damaging the native vessel, and secondly provides a separate endovascular attachment system that permanently attaches the graft to the vessel wall.
Disclosure of Invention
Methods and devices for implanting a radially expandable prosthesis in a body lumen are described. In particular, the present invention provides improved methods and systems for vascular stents and stent grafts implanted into blood vessels, including both arteries and veins. In an exemplary embodiment, the stent graft is placed in a blood vessel to reinforce an aneurysm, particularly an abdominal aortic aneurysm.
In a first aspect of the invention, at least one prosthetic stent is expanded by first expanding the stent at or near the implantation site within the body lumen, for example at or near the vascular structure on the side of a hemangioma. After expanding the stent of the prosthesis, a plurality of anchors are introduced through the prosthesis into the stent region to anchor the stent in place. The stent may be elastic, typically comprising a shape memory alloy elastic stainless steel or the like. For elastic stents, expansion typically involves releasing the stent from constraint to allow the stent to self-expand at the implantation site. The constraint may be a radial constraint, i.e., a tubular catheter, delivery sheath, or the like is placed over the stent to maintain the stent in a radially reduced configuration. Expansion is achieved by pulling back on the catheter sheath to allow the stent to return to its larger diameter configuration. In addition, the stent may be constrained to an axially elongated configuration, such as by attaching either end of the stent to an inner tube, rod, catheter or the like, to maintain the stent in an elongated, reduced diameter configuration. The stent is then released from such axial length constraint to allow it to self-expand.
Alternatively, the stent may be made of malleable material, such as malleable stainless steel or other metal. Expansion may then involve applying a radially expansive force within the stent to cause expansion, such as by inflating a stent delivery catheter within one side of the stent to cause expansion.
Vascular prostheses may have a variety of conventional configurations. In the preferred placement of a vascular stent graft, the prosthesis typically contains a semi-permeable flexible barrier to blood, such as fibers, supported by the stent, which is typically in the configuration of a stent. The stent may have any conventional stent configuration, such as a zig-zag, S-shape, expanded diamond shape, or combinations thereof. The stent structure may extend the entire length of the graft, and in some cases may be longer than the fibrous component of the graft. Alternatively, the stent will cover only a small portion of the prosthesis, occurring at 1, 2 or 3 ends. Where the stent graft is to be deployed for treatment of a weighted vascular region, such as for treatment of an abdominal aortic aneurysm, into the common iliac artery, the stent may have three or more ends. In some cases, the stents may be spaced along the entire length of the stent graft, or at least throughout a substantial portion of its entire length, where the individual stent structures are not directly connected to each other, but rather to the fibrous or other flexible component of the graft.
The introduction of the fixator is typically performed after the initial placement of the prosthesis. This initial placement is performed by self-expansion or balloon expansion, after which the prosthesis is fixed or anchored in place by introducing a plurality of individual anchors, preferably helical anchors that are rotated so as to "screw" into the prosthesis and the vessel wall. The anchors may be placed only through the fibers, i.e. avoiding the scaffold structure. Alternatively, the fasteners may be introduced into and through portions of the stent structure, optionally through a socket or slot that has been specially configured to receive the fastener. In some cases, of course, the holdfast will be introduced both through the fibers and over the scaffold structure.
In an exemplary embodiment, the fasteners are helical fasteners that are introduced individually, i.e., one at a time, in a circumferentially spaced pattern on the inner wall of the prosthesis. Typically, the fasteners are introduced using a fastener applicator carrying a single fastener. A fastener applicator carrying a single fastener has a lower profile and may be more efficient and less traumatic than a fastener applicator carrying multiple fasteners. However, it is contemplated that in certain embodiments the fastener applier may also carry a plurality of fasteners. Moreover, the fastener applier can deploy multiple fasteners simultaneously in the preferred annularly spaced spatial pattern described above. Typically, 2-12 fasteners are applied to each end of the prosthesis to be anchored. The 2-12 fasteners will typically be applied in a single, circularly spaced row, and the fasteners may be applied in more than one row, with the individual fasteners being axially aligned or circularly staggered. In a preferred embodiment, the endoluminal fastener applier of the invention comprises a guide member, e.g., a tubular body having a deflectable distal tip, and, optionally, stabilizers for maintaining the deflectable tip against position in the implant to which the fastener is to be applied. The applicator member may be inserted through the cavity of the guide member and carry at least one single helical or other fastener. A rotation means is provided for rotating and advancing the helical anchor so that it penetrates the graft and underlying vessel wall to securely anchor the graft in place.
The invention further relates to an endoluminal fastener applier comprising a tubular body with a deflectable distal tip; a stabilizer configured to engage a wall of the blood vessel to hold the distal end of the tubular body in place; a control handle at the proximal end of the tubular body having controls to independently deflect the distal end and deploy a stabilizer that holds the deflected distal end in place; and a anchor advancing means for advancing the anchor from the distal end into the vessel wall engaged by the distal end. In a preferred embodiment, the fastener advancing means comprises fastener dispensing means which can be introduced through the tubular body and which carry at least one fastener. In another preferred embodiment, the fastener dispensing apparatus comprises a flexible rod carrying a single helical fastener at its distal end, and means for rotating and advancing the helical fastener through tissue. In another preferred embodiment, the flexible rod has a helical track carrying a helical fastener, and a rotator wire engaging and rotating the helical fastener to cause advancement from the distal end of the body.
Drawings
The invention will be understood from the following detailed description of embodiments of the invention with reference to the accompanying drawings. In the drawings:
FIG. 1 is a perspective view of one embodiment of an endovascular graft delivery device, shown deployed within an abdominal arterial aneurysm;
FIG. 2 is a perspective view of one embodiment of deploying an endovascular graft within the aneurysm of FIG. 1;
FIG. 3 is a perspective view of the straight endovascular graft of FIG. 2 fully deployed;
FIG. 4 is a perspective view of a fully deployed weighted endovascular graft, cut away to show the stent anchored at one end.
FIG. 5 is a perspective view similar to FIG. 5 showing an alternative support structure;
FIG. 6 is a perspective view showing one embodiment of a device for guiding a fastener applier;
figure 7 is a perspective view showing the device of figure 6 after insertion of the deployed endovascular graft of figure 3, with both the graft and the stent broken away.
FIG. 8 is a perspective view of the device of FIG. 6, showing activation of one embodiment of a stabilization device attached to the guide;
fig. 9 is a perspective view of the control assembly of fig. 8 hinged to the guide means of fig. 6.
FIG. 10 is a perspective view of an alternative embodiment of the stabilization device shown in FIG. 8;
FIG. 11 is a perspective view illustrating activation of the alternative stabilization device of FIG. 10;
FIG. 12 is a perspective view illustrating another embodiment of the stabilization device shown in FIG. 8;
FIG. 13 is a perspective view illustrating activation of the stabilization device of FIG. 12;
FIG. 14 is one embodiment of a fastener applier;
FIG. 15 is a perspective view of the fastener applier of FIG. 14 disposed within the guide device of FIG. 6;
FIG. 16 is an enlarged cross-sectional view of one embodiment of the fastener applier of FIG. 14;
FIG. 17 is an enlarged cross-sectional view of the attachment applier showing one embodiment of the proximal end of the helical fastener and the drive mechanism;
FIG. 18 is an enlarged perspective view of one embodiment of the helical fastener shown in FIG. 16;
FIG. 19 is an enlarged view of the attachment applicator showing one embodiment of a control assembly for actuating the fastener applier;
FIG. 20 is an enlarged view of the attachment applied with the actuation of the stent implanted into the graft and vessel wall;
FIG. 21 shows an enlarged view of the completed attachment of the proximal graft to the vessel wall with the fastener of FIG. 3;
fig. 22 is a perspective view of the graft shown in fig. 4 fully attached to a blood vessel.
Detailed Description
Figure 1 depicts an endovascular graft delivery catheter 10 with a guide wire 12 placed within an abdominal aortic aneurysm 11. Fig. 2 depicts an initial stage of deployment of a graft within a vessel. The delivery catheter 10 has a removable cover 13 over the graft. When the cover is pulled proximally, the graft 14 expands to contact the inner wall of the vessel. The graft may conceivably be self-expanding or use an expansion member such as a balloon or a mechanical expansion body. The graft deployment procedure continues until the graft is fully deployed into the vessel. Grafts are contemplated that are straight or may be weighted. Fig. 3 shows a fully deployed straight graft 14, while fig. 4 depicts a fully deployed weighted graft 15. The guide wire 12 is used to deliver and position the graft, remaining within the vessel for access to the fastener attachment system. One embodiment of a graft stent 16 (stent) is shown in partial cross-section in fig. 4. The stent is described in the form of a simple zig-zag pattern, however the design of the stent may conceivably involve a more complex pattern 17 as shown in figure 5. Although only one stent structure within the graft is shown in fig. 4 and 5, it is contemplated that multiple separate stent structures may be incorporated into the graft.
Fig. 6 depicts one embodiment of the guide 18 with an obturator 19 disposed within the lumen of the guide and extending past the distal tip of the guide. The obturator has a lumen to allow it to be dispensed through a guidewire. Figure 7 shows the guiding device positioned inside the deployed endovascular graft over a guide wire 12. The guide device has incorporated stabilizing means 20 to help maintain the position of the guide device within the vessel. In one embodiment, the stabilization device 20 is spring loaded and positioned for use in removing an obturator in a guide device, see fig. 8. The guide means are actuated by a control assembly 21 as shown in figure 8. In one embodiment, the control assembly 21 features a movable wheel or lever 22, which movable wheel or lever 22 deflects the distal tip 23 of the guide 18 to a desired position, as shown in fig. 9. The present invention contemplates that the control assembly of the guide device may be actuated mechanically, electrically, hydraulically, or pneumatically. The control assembly has a lumen therethrough to allow passage of the occluding member and the fastener applier. Fig. 10 depicts another embodiment of the stabilization device as a movable post assembly 24. The movable strut assembly is actuated via a lever 25 on the control assembly shown in figure 11. In both embodiments (fig. 7 and 10), the stabilization device is at the distal end of the guide device. In another embodiment, the stabilization device may be in the form of an expandable member adjacent the distal tip of the guide, see fig. 12. In one embodiment, expandable member 26 is shown actuated via lever 25 on the control assembly, see fig. 13. However, it is also contemplated that such a stabilization device may feel inflated. In all embodiments, the stabilization device may be used to stabilize the guide member, whether concentric or eccentric within the vessel.
In another embodiment of the invention, a separate tubular device may be used in conjunction with the guide device to access the blood vessel. Such a separate tubular device may incorporate stabilizing means above the guide means.
FIG. 14 depicts one embodiment of the fastener applier 27. FIG. 14A is a detailed view of the distal end of the fastener applier. FIG. 15 depicts the fastener applier positioned where the fastener is to be installed via the cavity of the guide.
FIG. 16 shows an enlarged cross-sectional view of the fastener applier 27 and the guide device 18. In one embodiment of the fastener applier, the helical fastener 28 is rotated via a fastener driver 29 by a drive rod 30 connected to a control assembly 31. Drive rod 30 may be made of any material that allows it to both flex and rotate. The drive rod is connected to a fastener driver 29 which engages the threaded fastener and transmits torque thereto. FIG. 16 shows the coils of the helical fastener 28 engaged with the internal groove 32 in the fastener applier. It is envisaged that the groove is located along the entire length of the holdfast or within a portion of the length thereof. Fig. 17 is an enlarged sectional view of the fastener applier 27, showing one embodiment of the engagement between the fastener driver and the helical fastener 28 in a section of the fastener driver 29. In this embodiment, the proximal coil of the helical anchor is formed to create a diagonal member 33 spanning the diameter of the helical anchor. Similar helical fasteners are described in us patent 5,964,772; 5,824,008, respectively; 5,582,616 and 6,296,656, the disclosures of which are incorporated herein by reference in their entirety.
FIG. 18 depicts one embodiment of the helical fixation device 28, showing the diagonal members 33. FIG. 19 depicts one embodiment of the fastener applier 27 during actuation of the fastener applier control assembly. Actuation of the control assembly rotates the drive rod, the fastener driver and the helical fastener. This rotation causes the helical fastener 28 to travel in the inner groove 32 of the fastener applier and into the graft 14 and vessel wall 34, see FIG. 20. The control assembly of the fastener applier is contemplated to be actuated mechanically, electrically, hydraulically or pneumatically.
Fig. 21 shows the completed helical fastener 28 attaching the graft 14 to the vessel wall 34. It is contemplated that one or more anchors may be provided to securely attach the graft to the vessel wall.
Fig. 22 shows a perspective view of a graft prosthesis with both proximal and distal ends attached to the vessel wall. The present invention contemplates graft attachment for straight and weighted grafts 15 within the aorta and other branch vessels.
It will be understood that the components and/or features of the preferred embodiments described herein may be used together or separately and that the methods and apparatus described may be combined or modified in whole or in part. It is contemplated that the guide, the fastener applier and the helical fastener may be alternately oriented relative to each other, such as offset, bi-axial, etc. Moreover, it should be understood that various embodiments other than the other procedures not described herein may be used, such as vascular trauma, arteriotomy, prosthetic heart valve attachment, and attachment of other prostheses within the vascular system and, more generally, within the body.
The foregoing detailed description of the embodiments of the invention has been presented for purposes of illustration and description. Other modifications, which are within the scope and spirit of the disclosure, may be suggested to one of ordinary skill in the art.