Surgical implant devices and methods for their manufacture and use

[0001] The present application claims is a divisional application of U.S. patent application Ser. No. 11/888,009 (Pub. No. 2009/0005760), now U.S. Pat. No. 8,252,036 filed Jul. 31, 2007 (which application claims priority of U.S. Provisional Patent Application Ser. No. 60/834,401, filed Jul. 31, 2006 and U.S. Provisional Patent Application Ser. No. 60/834,627, filed Aug. 1, 2006), the entire disclosures of which are hereby incorporated herein by reference in their entireties.

[0002] The present invention relates to the field of vascular surgery and the treatment of aneurysms or other luminal vascular defects. Specifically, the present invention relates to a novel design for sealable endovascular implants and to methods of use for such implants in endovascular procedures for aneurysms of the thoracic or abdominal aorta or other vascular structural defects.

[0003] Aneurysms of the thoracic and abdominal aorta represent a degenerative process of the aorta that is often attributed to atherosclerosis. Aneurysms are defined as a focal dilatation with at least a 50% increase over normal arterial diameter, usually associated with a degradation of the aortic media, or other structural defect in the aortic wall.

[0004] Medical research has suggested that these lesions are prone to occur in areas subjected to significant redirection of blood flow during diastole; however, the exact cause of such aneurysms is not known. A familial tendency to symptomatic aneurysms has been suggested. Degenerative aneurysms account for more than 90% of all infrarenal aneurysms of the abdominal aorta. Other potential causes include infection, cystic medial necrosis, arteritis, trauma, collagen vascular disorders, and anastomotic disruption.

[0005] Abdominal aortic aneurysms most commonly begin in the infrarenal aorta, and extend down to the iliac bifurcation. Aneurysms of the thoracic aorta are most commonly located in the descending thoracic aorta, beginning just distal to the origin of the left subclavian artery.

[0006] Aortic aneurysms generally affect elderly Caucasian men. Aortic aneurysms are less commonly reported among persona of African American, Asian, and Hispanic heritage. Abdominal aortic aneurysms are five times more common in men than in women. In men, the aneurysm process appears to begin at approximately age fifty years and reaches peak incidence at approximately age eighty years. Women appear to have a more delayed onset in which the aneurysm process appears to begin at approximately age 60 years. Smoking has been associated as a potential risk factor for the development of aortic aneurysms. Other risk factors include previous aneurysm repair or peripheral aneurysm (such as femoral or popliteal), coronary artery disease, and hypertension.

[0007] Although the reported findings from autopsy series vary widely, the incidence of aortic aneurysms probably exceeds 3-4% in individuals older than 65 years. Death from aneurysmal rupture remains one of the 15 leading causes of death in the United States. In addition, the overall prevalence of aortic aneurysms has increased significantly in the last 30 years. This is partly due to an increase in diagnosis based on the widespread use of imaging techniques. However, the prevalence of fatal and nonfatal rupture has also increased, suggesting a true increase in incidence. An aging population probably plays a significant role.

[0008] The surgical management of aortic aneurysms dates back to the early twentieth century, and has involved a variety of methods, including ligation, intraluminal wiring, cellophane wrapping, homografts, and grafts using nylon and polytetrafluoroethylene [PTFE] fabrics.

[0009] Prior to the development of endoaneurysmorrhaphy in 1962, postoperative surgical mortality rates were high (>25%). Endovascular repair techniques have reduced the operative mortality to 1.8-5%.

[0010] Existing techniques for endovascular treatment of aneurysms involve placement of a tubular graft with seals to normal aortic walls above and below the aneurysm to create a tubular bridge to carry flow across the aneurysm without allowing flow to fill the aneurismal sac. Using these techniques, grafts may be placed using percutaneous access to the femoral arteries, and delivery/implantation using vascular catheters and fluoroscopic visualization. The deficiencies associated with existing endograft technology relate to leakage at the graft/aortic interface and/or post-implantation migration of the endograft. Small post-implantation leaks may be repaired with the placement of one or more extension cuffs above the endograft proximally, or below the implant distally to attempt to obtain a better seal with the vessel. The required use of such cuffs may add significantly to the overall cost and morbidity of the procedure. Major failures with endograft repair generally require emergent open surgery to avert catastrophic rupture of the aneurysm. Also, current endovascular systems require accurate size matching of endograft implants, leaving a very small margin for error.

[0011] In order for a patient to be a candidate for existing endograft methods and technologies, a proximal neck of at least 15 mm. of normal aorta must exist between the origin of the most inferior renal artery and the origin of the aneurysm in the case of abdominal aneurysms or the left subclavian artery for thoracic aortic aneurysms in order to permit an adequate seal. Similarly, at least 15 mm. of normal vessel must exist distal to the distal extent of the aneurysm for an adequate seal to be achieved.

[0012] Migration of existing endografts has also been a significant clinical problem, potentially causing leakage and re-vascularization of aneurysms and/or compromising necessary vascular supplies to arteries such as the carotid, subclavian, renal, or internal iliac vessels. This problem has been partially addressed by some existing endograft designs, in which barbs or hooks have been incorporated to help retain the endograft at its intended site. However, these existing endograft designs are not removable and repositionable once they are deployed. Thus, once such an endograft has been placed, open surgery is necessary if there is failure due to leakage or undesired occlusion of other vascular structures.

[0013] Because of the limitations imposed by existing vascular endograft devices and endovascular techniques, approximately eighty percent of abdominal and thoracic aneurysms repaired in the U.S. are still managed though open vascular surgery, instead of the lower morbidity of the endovascular approach.

[0014] The present invention is directed towards a novel design for endovascular implant grafts, and methods for their use for the treatment of aortic aneurysms and other structural vascular defects. A sealable, repositionable endograft system for placement in a blood vessel is disclosed, in which an endograft implant comprises a non-elastic tubular implant body with an elastic proximal end(s) and an elastic distal end(s). Both the elastic proximal and distal ends in an implant according to the present invention further comprise one or more circumferential sealable collars and one or more variable sealing device, capable of controllably varying the expanded diameter of said collar upon deployment to achieve the desired seal between the collar and the vessel's inner wall. An endovascular implant according to the present invention further comprises a central lumen and one or more control leads extending distally from releasable connections with each variable sealing device. Embodiments of endovascular implants according to the present invention may further be provided with retractable retention tines or other retention devices allowing an implant to be repositioned before final deployment. An endograft system according to the present invention further comprises a delivery catheter with an operable tubular sheath, capable of housing a folded or compressed endograft implant prior to deployment and capable of retracting or otherwise opening in at least its proximal end to allow implant deployment, said sheath sized and configured to allow its placement via a peripheral arteriotomy site, and of appropriate length to allow its advancement into the thoracic or abdominal aorta, as required for a specific application.

[0015] In use of an embodiment according to the present invention, an operator prepares an arteriotomy site in a patient in a suitable peripheral location, such as the femoral arteries. Upon incision into the artery, a guide wire is placed, and extended under radiographic visualization into the aorta. A catheter sheath is inserted, housing a collapsed endovascular graft. An injector cannula is inserted, with its proximal tip extending beyond the catheter sheath. Under radiographic visualization, radio-opaque or other contrast dye is injected into the injector cannula, and the contrast dye-enhanced view is used to position the proximal edge of the cannula above the beginning of the aneurysm sac. The catheter sheath is then partially retracted to expose the proximal portion of the endovascular implant. Through action initiated by the operator on the control leads, the variable sealing device for the proximal seal is activated, expanding the elastic circumferential sealable collar until firm contact is made with the vessel wall. At this point, additional radio-opaque or other contrast dye is injected, and the seal is assessed. If there are leaks, the variable sealing device is again activated to expand the diameter of the circumferential sealable collar for a firmer contact. The seal is reassessed and adjusted until there no contrast dye leaks are seen. If the radio-opaque or other contrast dye indicates that the device is placed too proximally and threatens or covers the renal or subclavian junctions, then it is loosened and moved distally.

[0016] Once the proximal circumferential sealable collar has been suitably sealed, the catheter sheath is then retracted beyond the distal extent of the aneurysm exposing the remainder of the graft. The variable sealing device for the distal seal is similarly activated, expanding the elastic circumferential sealable collar until firm contact is made with the vessel wall. At this point, additional radio-or other contrast dye is injected, and the distal seal is assessed. If there are leaks, the distal variable sealing device is again activated to expand the diameter of the distal circumferential sealable collar for a firmer contact. The seal is reassessed and adjusted until there no contrast dye leaks are seen.

[0017] For an implant for an abdominal aortic aneurysm according to the present invention, an endograft implant comprises a non-elastic tubular body with an elastic proximal and distal ends and a non-elastic contralateral cuff. An operator deploys and seals the proximal and distal ends of the implant as described above, with the distal end deployed and sealed in the iliac artery on the side of the initial arteriotomy. Then, a second arteriotomy is made on the opposite side. Radio-or other contrast dye injection is again used to allow visualization of the non-elastic contralateral cuff, and a second guide wire is placed from the second arteriotomy site through the non-elastic contralateral cuff. A contralateral delivery catheter is then introduced over the second guide wire. The contralateral delivery catheter comprises a slidable or removable sheath housing a folded or compressed endograft segmental implant which further comprises a non-elastic tubular body with an elastic proximal and distal ends. Both the elastic proximal and distal ends in an endograft segmental implant according to the present invention further comprise one or more circumferential sealable collars and one or more variable sealing device, capable of controllable varying the expanded diameter of said collar upon deployment to achieve the desired seal between the collar and the non elastic contralateral cuff proximally and between the collar and the vessel's inner wall distally. An endograft segmental implant according to the present invention further comprises a central lumen and one or more control leads extending distally from releasable connections with each variable sealing device.

[0018] Again, under radiographic control, radio-opaque or other contrast dye is injected into the injector cannula, and the contrast dye-enhanced view is used to position the proximal edge of the contralateral delivery catheter within the lumen of the non-elastic contralateral cuff. The contralateral delivery catheter sheath is then partially retracted to expose the proximal portion of the endograft segmental implant. Through action initiated by the operator on the control leads, the variable sealing device for the proximal seal is activated, expanding the elastic circumferential sealable collar until firm contact is made between the sealable collar and the non elastic cuff. At this point, additional radio-opaque or other contrast dye is injected, and the seal is assessed. If there are leaks, the variable sealing device is again activated to expand the diameter of the circumferential sealable collar for a firmer contact. The seal is reassessed and adjusted until there no contrast dye leaks are seen.

[0019] Finally, once the proximal circumferential sealable collar of the endograft segmental implant has been suitably sealed, the catheter sheath is then retracted beyond the distal extent of the aneurysm, exposing the remainder of the graft. The variable sealing device for the distal seal is similarly activated, expanding the elastic circumferential sealable collar until firm contact is made with the vessel wall. At this point, additional radio-opaque or other contrast dye is injected, and the distal seal is assessed. If there are leaks, the distal variable sealing device is again activated to expand the diameter of the distal circumferential sealable collar for a firmer contact. The seal is reassessed and adjusted until there no contrast dye leaks are seen. At this point, the operator may remove the injector cannula and detach the control leads from the variable sealing devices, and remove the control leads and guide wires from their arteriotomy sites and close the wounds.

[0020] The preceding description is presented only as an exemplary application of the devices and methods according to the present invention.

[0056] The present invention may be understood more readily by reference to the following detailed description of the preferred embodiments of the invention and the examples included herein. However, before the preferred embodiments of the devices and methods according to the present invention are disclosed and described, it is to be understood that this invention is not limited to the exemplary embodiments described within this disclosure, and the numerous modifications and variations therein that will be apparent to those skilled in the art remain within the scope of the invention disclosed herein. It is also to be understood that the terminology used herein is for the purpose of describing specific embodiments only and is not intended to be limiting.

[0057] Unless otherwise noted, the terms used herein are to be understood according to conventional usage by those of ordinary skill in the relevant art. In addition to the definitions of terms provided below, it is to be understood that as used in the specification and in the claims, “a” or “an” can mean one or more, depending upon the context in which it is used.

[0058] The present invention is directed towards novel designs for sealable and repositionable endovascular implant grafts, and methods for their use for the treatment of aortic aneurysms and other structural vascular defects.

[0059] In an exemplary embodiment according to the present invention, a sealable vascular endograft system for placement in a vascular defect is provided, comprising an elongated main implant delivery catheter with an external end and an internal end for placement in a blood vessel with internal walls. In such an exemplary embodiment, the main implant delivery catheter further comprises a main implant delivery catheter sheath which may be openable or removable at said internal end and a main implant delivery catheter lumen containing within a compressed or folded endovascular implant. Further in such an exemplary embodiment, an endovascular implant comprises a non-elastic tubular implant body with an elastic proximal end terminating in a proximal sealable circumferential collar controlled by a proximal variable sealing device which is operated by a proximal control lead that traverses said main implant delivery catheter and exits at said external end for interface by an operator, such that said proximal sealable circumferential collar may be expanded or contracted by said operator to achieve a fluid-tight seal between said proximal sealable circumferential collar and the internal walls of said blood vessel proximal to said vascular defect. Moreover, in such an exemplary embodiment, an endovascular implant further comprises a non-elastic tubular implant body with an elastic distal end terminating in a distal sealable circumferential collar controlled by a distal variable sealing device which is operated by a distal control lead that exits said main implant delivery catheter at said external end for interface by an operator, such that said distal sealable circumferential collar may be expanded or contracted by said operator to achieve a fluid-tight seal between said distal sealable circumferential collar and the internal walls of said blood vessel distal to the vascular defect.

[0060] Referring now in more detail to the drawings, in which like numerals indicate like elements throughout the several views, FIG. 1A shows a side perspective view of the proximal tip of a main implant delivery catheter 100 with a main implant delivery catheter lumen 102 containing a disclosed embodiment of compressed or folded endovascular implant 200 housed within a main implant delivery catheter sheath 104. The endovascular implant 200 in the embodiment shown in FIG. 1A includes a non-elastic tubular implant body 106 with an elastic proximal end 108 and an elastic distal end 110. The elastic proximal end 108 terminates in a proximal sealable circumferential collar 112, controlled by a proximal variable sealing device 116 which is operated by a proximal control lead 120 that traverses the main implant delivery catheter 100 and exits distally for interface with an operator (not shown in FIG. 1A). The elastic distal end 110 terminates in a distal sealable circumferential collar 114, controlled by a distal variable sealing device 118 which is operated by a distal control lead 122 that exits the main implant delivery catheter 100 distally for interface with an operator (not shown in FIG. 1A).

[0061] The embodiment of an endovascular implant 200 of FIG. 1A is further shown in FIG. 1B removed from the main implant delivery catheter 100 and in a semi- or partially expanded or non-folded state. In addition to the elements described in FIG. 1A, the endovascular implant 200 in the embodiment shown in FIG. 1B may also include a contralateral non-elastic cuff 126.

[0062] An alternate embodiment of a sealable endovascular implant according to the present invention is shown in FIG. 2A. The proximal tip of a main implant delivery catheter 100 with a main implant delivery catheter lumen 102 containing a disclosed embodiment of compressed or folded straight endovascular implant 202 housed within a main implant delivery catheter sheath 104. The endovascular implant 202 in the embodiment shown in FIG. 2A includes a non-elastic tubular implant body 106 with an elastic proximal end 108 and an elastic distal end 110. The elastic proximal end 108 terminates in a proximal sealable circumferential collar 112, controlled by a proximal variable sealing device 116 which is operated by a proximal control lead 120 that traverses the main implant delivery catheter 100 and exits distally for interface with an operator (not shown in FIG. 2A). The elastic distal end 110 terminates in a distal sealable circumferential collar 114, controlled by a distal variable sealing device 118 which is operated by a distal control lead 122 that exits the main implant delivery catheter 100 distally for interface with an operator (not shown in FIG. 2A).

[0063] The embodiment of an endovascular implant 202 of FIG. 2A is further shown in FIG. 2B removed from the main implant delivery catheter 100 and in an semi- or partially expanded or non-folded state. A straight endovascular implant 202 according to the embodiment shown in FIGS. 2A and 2B provides a non-branching conduit between the proximal sealable circumferential collar 112 and the distal sealable circumferential collar 114.

[0064] An embodiment of an endograft segmental implant according to the present invention is shown in FIG. 3. An endograft segmental implant 306 sealably interfaces to provide a conduit between a non-elastic vascular graft and a distal blood vessel. As shown in FIG. 3, an endograft segmental implant 306 includes a non-elastic tubular segmental implant body 308 with an elastic proximal segmental end 310 and an elastic distal segmental end 312. The elastic proximal segmental end 310 terminates in a proximal segmental sealable circumferential collar 314, controlled by a proximal segmental variable sealing device 318 which is operated by a proximal segmental control lead 322 that traverses a segmental implant delivery catheter (not shown in FIG. 3) and exits distally for interface with an operator (not shown in FIG. 3). The elastic distal segmental end 312 terminates in a distal sealable segmental circumferential collar 316, controlled by a distal segmental variable sealing device 320 which is operated by a distal segmental control lead 324 that exits a segmental implant delivery catheter distally for interface with an operator (not shown in FIG. 3).

[0065] In various embodiments according to the present invention, endovascular implants 200 may be constructed of solid, woven, non-woven, or mesh materials such as, but not limited to, natural or synthetic rubbers, nylon, Goretex, elastomers, polyisoprenes, polyphosphazenes, polyurethanes, vinyl plastisols, acrylic polyesters, polyvinylpyrrolidone-polyurethane interpolymers, butadiene rubbers, styrene-butadiene rubbers, rubber lattices, Dacron, PTFE, malleable metals, other biologically compatible materials or a combination of such biologically compatible materials in a molded, woven, or non-woven configuration, coated, non-coated, and other polymers or materials with suitable resilience and pliability qualities. In certain preferred embodiments according to the present invention, it is desirable for the non-elastic tubular implant body 106 and corresponding structures to be pliable to allow for folding or compressibility without allowing elasticity. In certain preferred embodiments according to the present invention, it is desirable for the elastic proximal end 108 and the elastic distal end 110 and corresponding structures to be both elastic and compressible or foldable. In any given preferred embodiment, the non-elastic tubular implant body 106, the elastic proximal end 108, the elastic distal end 110 and corresponding structures may be constructed of the same material of varying elasticity, or these structures may be constructed of different, but compatible materials.

[0066] FIGS. 4-9 illustrate an exemplary embodiment of sealable endovascular implants and an illustrative method of their use according to the present invention for the treatment of an infrarenal abdominal aortic aneurysm with vascular access through bilateral femoral arteriotomy sites.

[0067] In FIG. 4 a main implant delivery catheter 100 has been placed in a first side through a femoral artery (not shown in FIG. 4) and positioned in an abdominal aorta 402 in a location distal to the renal arteries 408, but above the origin of an abdominal aortic aneurysm 410.

[0068] FIG. 5 is a continuation of the disclosed embodiment of the present invention of FIG. 4 in which an injector cannula 404 with one or more injection ports 406 has been introduced through a main implant delivery lumen 102 of the main implant delivery catheter 100, and protrudes proximal to the tip of the implant delivery catheter 100 to fully expose the injector ports 406 for real-time visualization contrast dye injection therethrough. Such contrast dye injection may be performed using radio-opaque or other contrast dyes for fluoroscopy, computerized tomography, or other radiographic techniques. In alternate embodiments according to the present invention, other real-time visualization techniques may be used, including but not limited to, ultrasound or nuclear magnetic resonance techniques using appropriate contrast dye materials for injection. Such contrast dye injection allows an operator to assess the distance between the origins of the renal arteries 408, and the origin of the aortic aneurysmal sac 410 for proper implant placement.

[0069] FIG. 6 is a continuation of the disclosed embodiment of the present invention of FIG. 5 in which the main implant delivery catheter sheath 104 of the main implant delivery catheter 100 has been retracted or partially opened to allow the endovascular implant 200 therein to partially open or unfold from its initially compressed or folded position. Additional contrast dye injection through the injector cannula 404 may be performed by the operator at this point to verify the level of the proximal circumferential sealable collar 112 with respect to the level of the renal arteries 408. FIG. 7 is a continuation of the disclosed embodiment of the present invention of FIG. 6 in which the level of the proximal circumferential sealable collar 112 has been adjusted by the operator with respect to the level of the renal arteries 408 for optimal deployment.

[0070] FIG. 8 is a continuation of the disclosed embodiment of the present invention of FIG. 7 in which operator action on one or more proximal control leads 120 connected to one or more proximal variable sealing devices 116 has caused the proximal circumferential sealable collar 112 of the elastic proximal end 108 of the endovascular implant 200 to firmly and fully contact the aortic inner wall 124, effecting a vascular seal therein.

[0071] FIG. 9 is a continuation of the disclosed embodiment of the present invention of FIG. 8 in which operator action has fully retracted or opened and removed the main implant delivery sheath 104 of the main implant delivery catheter 100 allowing the endovascular implant 200 therein to fully decompress or unfold, thus exposing a distal elastic implant end 110 and a non-elastic contralateral cuff 126. At this point in a deployment procedure, additional contrast dye injection would likely again be performed to ascertain that there is a complete seal at the level of the proximal circumferential sealable collar 112. If leakage is still visualized, additional operator action on the proximal control lead (s) 120 may be used to further expand the proximal circumferential sealable collar 112 to secure an acceptable seal. Alternately, operator action may reduce the expanded proximal circumferential sealable collar 112 to allow its reposition and redeployment, again under real-time radiographic or other visualized control.

[0072] FIG. 10 is a continuation of the disclosed embodiment of the present invention of FIG. 9 once a suitable proximal seal has been achieved. Operator action on one or more distal control leads 122 connected to one or more distal variable sealing devices 118 has caused the extended distal circumferential sealable collar 114 of the endovascular implant's 200 elastic distal end 110 to firmly and fully contact the inner wall of the common iliac artery 412 above the origin of the internal iliac artery 414, effecting a vascular seal therein and preserving flow through the internal iliac artery 414. Additional contrast dye injection through the injector cannula 404 would be used by the operator to confirm adequate seals both proximally and distally at this point.

[0073] FIG. 11 is a continuation of the disclosed embodiment of the present invention of FIG. 10 in which operator action has placed a second guide wire 302 provided with an engagement tip 328 to grasp and stabilize the non-elastic contralateral cuff 126 under radiographic or other imaging control through an access via a second side through a femoral arteriotomy (not shown in FIG. 11).

[0074] FIG. 12 is a continuation of the disclosed embodiment of the present invention of FIG. 11 in which operator action has placed a contralateral delivery catheter 300 over the second guide wire 302. The contralateral delivery catheter 300 includes a contralateral delivery catheter lumen 304 and a contralateral delivery catheter sheath 340 which may be operably opened or retracted by operator action.

[0075] FIG. 13 is a continuation of the disclosed embodiment of the present invention of FIG. 12 in which operator action has removed the contralateral delivery catheter sheath 340 of the contralateral delivery catheter 300 allowing the endograft segmental implant 344 therein to fully decompress or unfold to expose a proximal segmental elastic implant end 348, a distal segmental elastic implant end 356, and the full length of a non-elastic segmental tubular implant body 346 connecting said ends 348 and 356.

[0076] FIG. 14 is a continuation of the disclosed embodiment of the present invention of FIG. 13 in which operator action on one or more proximal segmental control leads 354 connected to one or more proximal segmental variable sealing devices 352 has caused the expansion of proximal segmental circumferential sealable collar 350 of the endograft segmental implant's 344 elastic proximal segmental implant end 348 to firmly and fully contact the inner walls of the non-elastic contralateral cuff 126 effecting a proximal seal, and then similarly caused the distal segmental circumferential sealable collar 358 of the endograft segmental implant's 344 elastic distal segmental implant end 356 to expand to firmly and fully contact the inner wall of the common iliac artery 416 on the second side above the origin of the internal iliac artery 418, effecting a vascular seal therein and preserving flow through the internal iliac artery 418. Once sealed, the aortic aneurysmal sac 410 is devascularized and collapses.

[0077] FIG. 15 shows a diagrammatic view of a patient 500 in a dorsal supine position, with a disclosed embodiment of an endovascular implant 200 according to the present invention in sealed position in the patient's abdominal aorta 402 proximally and distally, and with arteriotomy incisions 332, 336 in both femoral arteries with an injector cannula 404 for radiographic contrast dye injection and proximal 120 and distal 122 control leads for operator manipulation in place in the patient's right arteriotomy site 332 and a second guide wire 302 in place in the patient's left arteriotomy site 336, corresponding to the procedural stage shown in FIG. 11.

[0078] FIG. 16 shows an anatomic view of a disclosed embodiment of a thoracic endovascular implant 600 according to the present invention in sealed position proximally and distally in a patient's descending thoracic aorta 612, traversing a devascularized thoracic aortic aneurysm 614. In a patient, the ascending aorta 604 arises from the heart 602 and gives rise to the innominate artery 606, the left common carotid artery 608, and the left subclavian artery 610 before continuing as the descending thoracic aorta 612. The thoracic endovascular implant 600 includes a non-elastic tubular thoracic implant body 616 with an elastic proximal thoracic end 618 and an elastic distal thoracic end 626. The elastic proximal thoracic end 618 terminates in a proximal thoracic sealable circumferential collar 620, controlled by a proximal thoracic variable sealing device 622 which is operated by a proximal thoracic control lead 624 that traverses a thoracic implant delivery catheter (not shown in FIG. 16) and exits distally for interface with an operator (not shown in FIG. 16). The elastic distal thoracic end 626 terminates in a distal sealable thoracic circumferential collar 628, controlled by a distal thoracic variable sealing device 630 which is operated by a distal thoracic control lead 632 that exits a thoracic implant delivery catheter distally for interface with an operator (not shown in FIG. 6).

[0079] FIG. 17 provides an anatomic view showing an alternate disclosed embodiment of a thoracic endovascular implant 700 in a patient's descending thoracic aorta 612 according to the present invention in which a first thoracic endovascular implant 718 includes a non-elastic distal cuff 730, a proximal first thoracic circumferential sealable collar 724, a proximal first thoracic variable sealing device 726, and a proximal first thoracic control lead 728. As shown in FIG. 17, the first thoracic endovascular implant 718 has been sealed in position proximally by operator action on the proximal first thoracic variable sealing device 726 using the proximal first thoracic control lead 728, expanding the proximal first thoracic circumferential sealable collar 724 to achieve a proximal seal within the descending thoracic aorta 612, and effectively devascularizing a thoracic aneurysm 614 therein.

[0080] As further shown in FIG. 17, the first thoracic endovascular implant 718 has been joined distally by a second thoracic endovascular implant 732, which includes an elastic proximal second thoracic implant end 736, a non-elastic tubular second thoracic implant body 734, and an elastic distal second thoracic implant end 746. The elastic proximal second thoracic implant end 736 includes a proximal second thoracic circumferential sealable collar 738, a proximal second thoracic variable sealing device 740, and a proximal second thoracic control lead 742, and the elastic distal second thoracic implant end 746 includes a distal second thoracic circumferential sealable collar 748, a distal second thoracic variable sealing device 750, and a distal second thoracic control lead 752.

[0081] In an exemplary application according to the present invention as shown in FIG. 17, an operator would first secure a seal in the proximal descending thoracic aorta using the first thoracic endovascular implant 718, and then seal the proximal and distal aspects, respectively, of the second thoracic endovascular implant 732, using real-time radiographic or other visualization techniques with injected contrast dye as previously described in this disclosure.

[0082] FIGS. 18A and 18B show an embodiment of an endovascular implant according to the present invention similar to the disclosure of FIG. 1B, with the additional inclusion of one of more retention tines 136 attached to the proximal circumferential sealable collar 112 and distal circumferential sealable collar 114.

[0083] In a preferred embodiment according to the present invention, a plurality of retention tines 136 is used. In a preferred embodiment according to the present invention, the retention tines 136 are oriented to extend radially outward from the proximal circumferential sealable collar 112 and distal circumferential sealable collar 114. In various preferred embodiment according to the present invention, the retention tines 136 may be oriented to extend perpendicularly or at any other desired angle outward from the proximal circumferential sealable collar 112 and distal circumferential sealable collar 114.

[0084] In various preferred embodiment according to the present invention, the retention tines 136 may be constructed of any biocompatible material including, but not limited to, metals, plastics, or ceramics.

[0085] As further shown in FIG. 18B the retention tines 136 of the proximal circumferential sealable collar 112 and distal circumferential sealable collar 114 covered by a compressible foam sheathing 134 in a pre-deployment position. In various preferred embodiment according to the present invention, the compressible foam sheathing 134 may be constructed of any biocompatible material of suitable compressibility to allow the foam to be substantially compressed by the pressure of the proximal circumferential sealable collar 112 and distal circumferential sealable collar 114 against the inner wall of a target artery, upon operator deployment. The compressible foam sheathing 134 may also be constructed of material of suitable memory characteristics to allow the foam to substantially decompress to its pre-deployment position, covering the retention tines 136, if pressure against the arterial wall is removed, thus allowing repositioning or removal of an endovascular implant according to the present invention at the operator's discretion.

[0086] Compressible foam sheathing 134 may be any biocompatible foam material of either an open or closed cell structure with sufficient compressibility and resilience to allow rapid recovery in a non-compressed state. In various preferred embodiments according to the present invention, such foam materials may be viscoelastic foam with a compressible cellular material that has both elastic (spring-like) and viscous (time-dependent) properties. Viscoelastic foam differs from regular foam by having time-dependent behaviors such as creep, stress relaxation, and hysteresis.

[0087] FIGS. 19A and 19B show the exemplary endovascular implant of FIGS. 18A and 18B in the anatomic context of an endovascular implant 200 being deployed and sealed proximally in an abdominal aorta 402 containing an aneurysm 410, with complete expansion and seal at the level of the proximal circumferential sealable implant collar 112 against the aortic inner wall 124, but incomplete expansion and no seal against the arterial inner wall 144 at the level of the distal circumferential sealable implant collar 114 at this stage of the procedure. As shown in the cross-sectional view of FIG. 19B, the retention tines 136 of the proximal circumferential sealable collar 112 and distal circumferential sealable collar 114 are covered by a compressible foam sheathing 134 in a pre-deployment position.

[0088] FIGS. 20A and 20B further show the exemplary endovascular implant of FIGS. 18A and 18B in the anatomic context of an endovascular implant 200 being deployed and sealed proximally in an abdominal aorta 402 containing an aneurysm 410, now with complete expansion of the distal circumferential sealable implant collar 114 and complete seal against the arterial inner wall 144 at this stage of the procedure. As shown in the cross-sectional view of FIG. 20B, compressible foam sheathing 134 is compressed between the distal circumferential sealable collar 114 and the arterial inner wall 144, allowing the retention tines 136 to engage the arterial inner wall 144 in their deployed position, thereby serving to retain the deployed position of the endovascular implant 200.

[0089] In given various preferred embodiments according to the present invention, retention tines 136 and the compressible foam sheathing 134 as described above may be used in conjunction with any or all circumferentially sealable elements in this disclosure, including but not limited to, proximal circumferential sealable collars 112, distal circumferential sealable collars 114, proximal segmental circumferential sealable collars 314, distal segmental circumferential sealable collars 316, proximal thoracic circumferential sealable collars 620, distal thoracic circumferential sealable collars 628, proximal first thoracic circumferential sealable collars 724, proximal second thoracic circumferential sealable collars 738, and distal second thoracic circumferential sealable collars 748.

[0090] FIGS. 21A-D illustrate details of an embodiment of a variable sealing device according to the present invention. A variable sealing mechanism assembly 2100 comprises a sealing device housing 2102 attached to a sealer belt 2104 with a sealer belt fixed end 2108 attached to said housing 2102 and with a sealer belt moveable end 2110 operably passing through said housing and collecting in a concentric belt receiver channel 2130 as said sealer belt moveable end 2110 exits said housing 2102. The sealer belt moveable end 2110 contains a plurality of uniformly distributed belt engagement slots 2106. The belt engagement slots 2106 may be round, oval, square, rectangular, triangular, or any other shape, but are sized, spaced, and configured on said sealer belt moveable end 2110 to engage with sealer gear teeth 2116 of a sealer gear 2114 rotatably located within a housing gear recess 2112 contained within said housing 2102. The sealer gear teeth 2116 are oriented to present on the outer circumference of said sealer gear 2114. On the inner circumference of said sealer gear 2114, a plurality of uniformly distributed sealer gear retainment slots 2118 are configured to receive a locking member 2120. The locking member 2120, in various embodiments according to the present invention may be a simple strip or bar as shown in FIGS. 21A-D, or it may be triangular, cross-shaped, stellate or other geometric shapes that would allow the sealer gear retainment slots 2118 to receive the ends of said locking member 2120. The locking member 2120 is fabricated of a metal or plastic with resilient spring-like properties, such that, when depressed or pulled in a perpendicular vector with respect to the sealer gear 2114, the ends of said locking member 2120 are withdrawn from the sealer gear retainment slots 2118, thus allowing the sealer gear 2114 to rotate within said housing gear recess 2112, as shown in FIGS. 21B and C. The locking member 2120 is further provided with one or more sealer gear drive pins 2126, which are received in gear drive pin slots 2128 of said sealer gear 2114 when the locking member 2120 is depressed, as shown in FIG. 21C. In various preferred embodiments according to the present invention, the gear drive pins 2126 and the gear drive pin slots 2128 may be tapered, straight, or otherwise shaped to facilitate their secure engagement and release. The locking member 2120 is depressed by action of a control lead shaft 2124, which is removably attached to the locking member 2120 at a control lead attachment 2122. In an exemplary embodiment of the present invention, as shown in FIG. 21C, while the locking member 2120 is released from the gear drive pin slots 2128 by a depressing action of the control lead shaft 2124, rotation of the control lead shaft 2124 will permit the sealer gear drive pins 2126 to transmit a rotational force to the sealer gear 2114, engaging the belt engagement slots 2106 in the movable end of the sealer belt 2110, and causing the movable end of the sealer belt 2110 to move in or out of the concentric belt receiver channel 2130. This motion has the effect of increasing or decreasing the surface area of the sealer belt 2104.

[0091] FIG. 21D shows an exemplary embodiment according to the present invention, in which a sealable collar 2140 contains a variable sealing mechanism assembly 2100 comprising a sealing device housing 2102 attached to a sealer belt 2104 with a sealer belt fixed end 2108 attached to said housing 2102 and with a sealer belt moveable end 2110 operably passing through said housing and collecting in a concentric belt receiver channel 2130 as said sealer belt moveable end 2110 exits said housing 2102. The sealable collar 2140 is constructed of a tubular elastic body in a closed loop defining a central collar lumen 2142. The sealer belt 2104 may pass circumferentially through substantially all of the sealable collar 2140, as shown in FIG. 21D, but in alternate embodiments may pass through only some of the circumference of the sealable collar 2140. As the variable sealing mechanism assembly 2100 is operated, the length of the sealer belt 2104 may enlarge or constrict, with similar action on the sealable collar 2140, thus allowing a variable seal to be achieved between the sealable collar 2140 and the inner lumen of a vessel wall (not shown in FIG. 21D) containing the sealable collar 2140.

[0092] Within certain embodiments of the present invention, an endograft may also incorporate radio-opaque, echogenic materials and magnetic resonance imaging (MRI) responsive materials (i.e., MRI contrast agents) to aid in visualization of the device under x-ray, ultrasound, fluoroscopy MRI or other imaging modalities. In addition, various embodiments according to the present invention may incorporate markers comprising various radio-opaque, echogenic materials and magnetic resonance imaging (MRI) responsive materials that may be placed on the walls of an aneurysm sac or on other anatomic sites for improved postoperative visualization to monitor for aneurysmal revascularization.

[0093] As shown in FIGS. 22A-22F, various embodiments according to the present invention may also be provided with one or more endograft monitoring devices to facilitate diagnosis of postoperative graft failure and aneurysm revascularization. In some embodiments according to the present invention, endograft monitoring devices may be pressure sensors positioned to demonstrate positive pressure within the former aneurysmal sac in some manner that may be identifiable by electronic, radiographic, or other visual or electronic communications. FIGS. 22A-F illustrate yet other embodiments of endograft monitoring devices according to the present invention.

[0094] FIGS. 22A-22B show an embodiment of a sealable vascular endograft system 2200 which incorporates an endograft monitoring device comprising an radio-opaque graft attachment member 2205 joined at a monitoring pivot 2210 to a radio-opaque aneurysmal attachment 2220 which is affixed by an operator at the time of endograft placement to the inner wall of the aneurysmal sac 2215, which is shown in a collapsed, nonvascularized state in FIG. 22A, but in an expanded, revascularized state in FIG. 22B. As further shown in FIG. 22B, the expansion of the aneurysmal sac 2215, has the further effect of increasing the angle between the radio-opaque graft attachment member 2205 and the radio-opaque aneurysmal attachment 2220. In such an embodiment, plain radiographs or other visualization means could be employed to evaluate the angle between the attachment members of an endograft monitoring device to detect endograft failure and revascularization of the aneurysm without requiring more invasive and expensive diagnostic studies.

[0095] FIGS. 22C and 22D illustrate yet another embodiment of an embodiment of a sealable vascular endograft system 2200 which incorporates an endograft monitoring device comprising an radio-opaque graft attachment 2202 pivotably joined by two or more radio-opaque graft frame members 2212 which are in turn joined frame pivots 2204 to radio-opaque aneurysmal frame members 2214 which are joined at an aneurysmal attachment 2216 which is affixed by an operator at the time of endograft placement to the inner wall of the aneurysmal sac 2215, which is shown in a collapsed, nonvascularized state in FIG. 22C, but in an expanded, revascularized state in FIG. 22D. As further shown in FIG. 22D, the expansion of the aneurysmal sac 2215, has the further effect of increasing the angles between the radio-opaque graft frame member 2212 and the radio-opaque aneurysmal frame members 2214 to create a square or polygonal shape visible on radiographs. In such an embodiment, plain radiographs or other visualization means could again be employed to evaluate the angles between the attachment members of an endograft monitoring device to detect endograft failure and revascularization of the aneurysm without requiring more invasive and expensive diagnostic studies.

[0096] FIGS. 22E and 22F illustrate still another embodiment of an embodiment of a sealable vascular endograft system 2200 which incorporates an endograft monitoring device comprising two or more radio-opaque graft attachment 2202 pivotably joined by two or more radio-opaque graft frame members 2212 which are in turn joined frame pivots 2204 to radio-opaque aneurysmal frame members 2214 which are joined at two or more aneurysmal attachments 2216 which are affixed by an operator at the time of endograft placement to the inner wall of the aneurysmal sac 2215, which is shown in a collapsed, nonvascularized state in FIG. 22E, but in an expanded, revascularized state in FIG. 22F. As further shown in FIG. 22F, the expansion of the aneurysmal sac 2215, has the further effect of increasing the angles between the radio-opaque graft frame member 2212 and the radio-opaque aneurysmal frame members 2214 to create a square or polygonal shape visible on radiographs. In such an embodiment, three-dimensional, cage-like structures could be formed by the various frame members described, further enhancing the clinical visibility of an indication of aneurysmal revascularization.

[0097] Although the foregoing embodiments of the present invention have been described in some detail by way of illustration and example for purposes of clarity and understanding, it will be apparent to those skilled in the art that certain changes and modifications may be practiced within the spirit and scope of the present invention. Therefore, the description and examples presented herein should not be construed to limit the scope of the present invention, the essential features of which are set forth in the appended claims.