US20150202066A1 - Delivery system and method for self-centering a proximal end of a stent graft - Google Patents

Abstract

A method for implanting a prosthesis centrally within a curved lumen includes loading a prosthesis into a delivery sheath, advancing the sheath in a patient towards the curved lumen to place at least the proximal end of the prosthesis within the curved lumen, and centering the proximal end of the prosthesis and/or the distal end of the sheath within the curved lumen. In a first advancing step, the outer catheter containing the inner sheath is advanced together towards the curved lumen to a location proximal of the curved lumen and, in a second advancing step, the inner sheath containing the prosthesis is advanced into the curved lumen to place at least the proximal end within the curved lumen while the outer catheter substantially remains at the location. After centering, the proximal end of the prosthesis is deployed centered within the curved lumen.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS
• This application is a continuation of U.S. patent application Ser. No. 13/024,882, filed Feb. 10, 2011, which is a continuation of U.S. patent application Ser. No. 11/701,876, filed Feb. 1, 2007, now abandoned, which claims the benefit under 35 U.S.C. §119(e) of U.S. Provisional Application Nos. 60/851,282, filed Oct. 12, 2006, 60/833,533, filed Jul. 26, 2006, and 60/765,449, filed Feb. 3, 2006. U.S. application Ser. No. 11/701,876 is also a continuation-in-part of U.S. patent application Ser. No. 10/884,136, filed Jul. 2, 2004, now U.S. Pat. No. 7,763,063, which claims the benefit under 35 U.S.C. §119(e) of U.S. Provisional Applications Nos. 60/500,155, filed Sep. 4, 2003, and 60/499,652, filed Sep. 3, 2003; and is also a continuation-in-part of U.S. patent application Ser. No. 10/784,462, filed Feb. 23, 2004, now U.S. Pat. No. 8,292,943, which also claims the benefit under 35 U.S.C. §119(e) of U.S. Provisional Applications Nos. 60/500,155, filed Sep. 4, 2003, and 60/499,652, filed Sep. 3, 2003. The entire teachings of the above applications are incorporated herein by reference.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
• n/a
BACKGROUND OF THE INVENTION
• 1. Field of the Invention
• The invention lies in the field of endoluminal blood vessel repairs. The invention specifically relates to a delivery system and method for self-centering a proximal end of a stent graft, for example, for endoluminally repairing aneurysm and/or dissections of the thoracic transverse aortic arch, thoracic posterior aortic arch, and the descending thoracic portion of the aorta. The present invention lies in the field of prosthesis delivery systems, in particular, to a stent capture device for releasably holding a stent graft in an endovascular stent graft delivery system.
• 2. Description of the Related Art
• A stent graft is an implantable device made of a tube-shaped surgical graft covering and an expanding or self-expanding frame. The stent graft is placed inside a blood vessel to bridge, for example, an aneurismal, dissected, or other diseased segment of the blood vessel, and, thereby, exclude the hemodynamic pressures of blood flow from the diseased segment of the blood vessel.
• In selected patients, a stent graft advantageously eliminates the need to perform open thoracic or abdominal surgical procedures to treat diseases of the aorta and eliminates the need for total aortic reconstruction. Thus, the patient has less trauma and experiences a decrease in hospitalization and recovery times. The time needed to insert a stent graft is substantially less than the typical anesthesia time required for open aortic bypass surgical repair, for example.
• Use of surgical and/or endovascular grafts have widespread use throughout the world in vascular surgery. There are many different kinds of vascular graft configurations. Some have supporting framework over their entirety, some have only two stents as a supporting framework, and others simply have the tube-shaped graft material with no additional supporting framework, an example that is not relevant to the present invention.
• One of the most commonly known supporting stent graft frameworks is that disclosed in U.S. Pat. Nos. 5,282,824 and 5,507,771 to Gianturco (hereinafter collectively referred to as “Gianturco”). Gianturco describes a zig-zag-shaped, self-expanding stent commonly referred to as a z-stent. The stents are, preferably, made of nitinol, but also have been made from stainless steel and other biocompatible materials.
• There are various features characterizing a stent graft. The first significant feature is the tube of graft material. This tube is commonly referred to as the graft and forms the tubular shape that will, ultimately, take the place the diseased portion of the blood vessel. The graft is, preferably, made of a woven sheet (tube) of polyester or PTFE. The circumference of the graft tube is, typically, at least as large as the diameter and/or circumference of the vessel into which the graft will be inserted so that there is no possibility of blood flowing around the graft (also referred to as endoleak) to either displace the graft or to reapply hemodynamic pressure against the diseased portion of the blood vessel. Accordingly, to so hold the graft, self-expanding frameworks are attached typically to the graft material, whether on the interior or exterior thereof. Because blood flow within the lumen of the graft could be impaired if the framework was disposed on the interior wall of the graft, the framework is connected typically to the exterior wall of the graft. The ridges formed by such an exterior framework help to provide a better fit in the vessel by providing a sufficiently uneven outer surface that naturally grips the vessel where it contacts the vessel wall and also provides areas around which the vessel wall can endothelialize to further secure the stent graft in place.
• One of the significant dangers in endovascular graft technology is the possibility of the graft migrating from the desired position in which it is installed. Therefore, various devices have been created to assist in anchoring the graft to the vessel wall.
• One type of prior art prosthetic device is a stent graft made of a self-expanding metallic framework. For delivery, the stent graft is, first, radially compressed and loaded into an introducer system that will deliver the device to the target area. When the introducer system holding the stent graft positioned in an appropriate location in the vessel and allowed to open, the radial force imparted by the self-expanding framework is helpful, but, sometimes, not entirely sufficient, in endoluminally securing the stent graft within the vessel.
• U.S. Pat. No. 5,824,041 to Lenker et al. (hereinafter “Lenker”) discloses an example of a stent graft delivery system. Lenker discloses various embodiments in which a sheath is retractable proximally over a prosthesis to be released. With regard to FIGS. 7 and 8, Lenker names components 72 and 76, respectively, as “sheath” and “prosthesis-containment sheath.” However, the latter is merely the catheter in which the prosthesis 74 and the sheath 72 are held. With regard to FIGS. 9 and 10, the sheath 82 has inner and outer layers 91, 92 fluid-tightly connected to one another to form a ballooning structure around the prosthesis P. This ballooning structure inflates when liquid is inflated with a non-compressible fluid medium and flares radially outward when inflated. With regard to FIGS. 13 to 15, Lenker discloses the “sheath” 120, which is merely the delivery catheter, and an eversible membrane 126 that “folds back over itself (everts) as thesheath 120 is retracted so that there are always two layers of the membrane between the distal end of the sheath [120] and the prosthesis P.” Lenker at col. 9, lines 63 to 66. The eversion (peeling back) is caused by direct connection of the distal end 130 to thesheath 120. The Lenker delivery system shown in FIGS. 19A to 19D holds the prosthesis P at both ends 256, 258 while an outer catheter 254 is retracted over the prosthesis P and the inner sheath 260. The inner sheath 260 remains inside the outer catheter 254 before, during, and after retraction. Another structure for holding the prosthesis P at both ends is illustrated in FIGS. 23A and 23B. Therein, the proximal holder having resilient axial members 342 is connected to a proximal ring structure 346. FIGS. 24A to 24C also show an embodiment for holding the prosthesis at both ends inside thin-walled tube 362.
• To augment radial forces of stents, some prior art devices have added proximal and/or distal stents that are not entirely covered by the graft material. By not covering with graft material a portion of the proximal/distal ends of the stent, these stents have the ability to expand further radially than those stents that are entirely covered by the graft material. By expanding further, the proximal/distal stent ends better secure to the interior wall of the vessel and, in doing so, press the extreme cross-sectional surface of the graft ends into the vessel wall to create a fixated blood-tight seal.
• One example of such a prior art exposed stent can be found in United States Patent Publication US 2002/0198587 to Greenberg et al. The modular stent graft assembly therein has a three-part stent graft: a two-part graft having anaortic section 12 and an iliac section 14 (with four sizes for each) and a contralateral iliac occluder 80. FIGS. 1, 2, and 4 to 6 show theattachment stent 32. As illustrated in FIGS. 1, 2, and 4, theattachment stent 32, while rounded, is relatively sharp and, therefore, increases the probability of puncturing the vessel.
• A second example of a prior art exposed stent can be found in U.S. Patent Publication 2003/0074049 to Hoganson et al. (hereinafter “Hoganson”), which discloses a coveredstent 10 in which the elongated portions orsections 24 of the ends 20a and 20b extend beyond the marginal edges of thecover 22. See Hoganson at FIGS. 1, 3, 9, 11a, 11b, 12a, 12b, and 13. However, these extending exposed edges are triangular, with sharp apices pointing both upstream and downstream with regard to a graft placement location. Such a configuration of the exposed stent 20a, 20b increases the possibility of puncturing the vessel. In various embodiments shown in FIGS. 6a, 6b, 6c, 10, 14a, Hoganson teaches completely covering the extended stent and, therefore, the absence of a stent extending from thecover 22. It is noted that the Hoganson stent is implanted by inflation of a balloon catheter.
• Another example of a prior art exposed stent can be found in U.S. Pat. No. 6,565,596 to White et al. (hereinafter “White I”), which uses a proximally extending stent to prevent twisting or kinking and to maintain graft against longitudinal movement. The extending stent is expanded by a balloon and has a sinusoidal amplitude greater than the next adjacent one or two sinusoidal wires. White I indicates that it is desirable to space wires adjacent upstream end of graft as close together as is possible. The stent wires of White I are actually woven into graft body by piercing the graft body at various locations. See White I at FIGS. 6 and 7. Thus, the rips in the graft body can lead to the possibility of the exposed stent moving with respect to the graft and of the graft body ripping further. Between the portions of the extendingstent 17, the graft body has apertures.
• The stent configuration of U.S. Pat. No. 5,716,393 to Lindenberg et al. is similar to White I in that the outermost portion of the one-piece stent—made from a sheet that is cut/punched and then rolled into cylinder—has a front end with a greater amplitude than the remaining body of the stent.
• A further example of a prior art exposed stent can be found in U.S. Pat. No. 6,524,335 to Hartley et al. (hereinafter “Hartley”). FIGS. 1 and 2 of Hartley particularly disclose a proximal first stent 1 extending proximally from graft proximal end 4 with both the proximal and distal apices narrowing to pointed ends.
• Yet another example of a prior art exposed stent can be found in U.S. Pat. No. 6,355,056 to Pinheiro (hereinafter “Pinheiro 1”). Like the Hartley exposed stent, Pinheiro discloses exposed stents having triangular, sharp proximal apices.
• Still a further example of a prior art exposed stent can be found in U.S. Pat. No. 6,099,558 to White et al. (hereinafter “White II”). The White II exposed stent is similar to the exposed stent of White I and also uses a balloon to expand the stent.
• An added example of a prior art exposed stent can be found in U.S. Pat. No. 5,871,536 to Lazarus, which discloses two support members 68 longitudinally extending from proximal end to a rounded point. Such points, however, create a very significant possibility of piercing the vessel.
• An additional example of a prior art exposed stent can be found in U.S. Pat. No. 5,851,228 to Pinheiro (hereinafter “Pinheiro II”). The Pinheiro II exposed stents are similar to the exposed stents of Pinheiro I and, as such, have triangular, sharp, proximal apices.
• Still another example of a prior art exposed stent can be found in Lenker (U.S. Pat. No. 5,824,041), which shows a squared-off end of the proximal and distal exposedband members 14. A portion of the exposedmembers 14 that is attached to thegraft material 18, 20 is longitudinally larger than a portion of the exposedmembers 14 that is exposed and extends away from thegraft material 18, 20. Lenker et al. does not describe themembers 14 in any detail.
• Yet a further example of a prior art exposed stent can be found in U.S. Pat. No. 5,824,036 to Lauterjung, which, of all of the prior art embodiments described herein, shows the most pointed of exposed stents. Specifically, the proximal ends of the exposed stent are apices pointed like a minaret. The minaret points are so shaped intentionally to allow forks 300 (see Lauterjung at FIG. 5) external to the stent 154 to pull the stent 154 from the sheath 302, as opposed to being pushed.
• A final example of a prior art exposed stent can be found in U.S. Pat. No. 5,755,778 to Kleshinski. The Kleshinski exposed stents each have two different shaped portions, a triangular base portion and a looped end portion. The totality of each exposed cycle resembles a castellation. Even though the end-most portion of the stent is curved, because it is relatively narrow, it still creates the possibility of piercing the vessel wall.
• All of these prior art stents suffer from the disadvantageous characteristic that the relatively sharp proximal apices of the exposed stents have a shape that is likely to puncture the vessel wall.
• Devices other than exposed stents have been used to inhibit graft migration. A second of such devices is the placement of a relatively stiff longitudinal support member longitudinally extending along the entirety of the graft.
• The typical stent graft has a tubular body and a circumferential framework. This framework is not usually continuous. Rather, it typically takes the form of a series of rings along the tubular graft. Some stent grafts have only one or two of such rings at the proximal and/or distal ends and some have many stents tandemly placed along the entirety of the graft material. Thus, the overall stent graft has an “accordion” shape. During the systolic phase of each cardiac cycle, the hemodynamic pressure within the vessel is substantially parallel with the longitudinal plane of the stent graft. Therefore, a device having unsecured stents, could behave like an accordion, or concertina with each systolic pulsation, and may have a tendency to migrate downstream. (A downstream migration, to achieve forward motion, has a repetitive longitudinal compression and extension of its cylindrical body.) Such movement is entirely undesirable. Connecting the stents with support along the longitudinal extent of the device thereof can prevent such movement. To provide such support, a second anti-migration device can be embodied as a relatively stiff longitudinal bar connected to the framework.
• A clear example of a longitudinal support bar can be found in Pinheiro I (U.S. Pat. No. 6,355,056) and Pinheiro II (U.S. Pat. No. 5,851,228). Each of these references discloses a plurality of longitudinally extendingstruts 40 extending between and directly interconnecting the proximal and distal exposed stents 20a, 20b. These struts 40 are designed to extend generally parallel with the inner lumen 15 of thegraft 10, in other words, they are straight.
• Another example of a longitudinal support bar can be found in U.S. Pat. No. 6,464,719 to Jayaraman. The Jayaraman stent is formed from a graft tube 21 and a supporting sheet 1 made of nitinol. This sheet is best shown in FIG. 3. The end pieces 11, 13 of the sheet are directly connected to one another by wavy longitudinal connecting pieces 15 formed by cutting the sheet 1. To form the stent graft, the sheet 1 is coiled with or around the cylindrical tube 21. See FIGS. 1 and 4. Alternatively, a plurality of connecting pieces 53 with holes at each end thereof can be attached to a cylindrical fabric tube 51 by stitching or sutures 57, as shown in FIG. 8. Jayaraman requires more than one of these serpentine shaped connecting pieces 53 to provide longitudinal support.
• United States Patent Publication 2002/0016627 and U.S. Pat. No. 6,312,458 to Golds each disclose a variation of a coiled securingmember 20.
• A different kind of supporting member is disclosed in FIG. 8 of U.S. Pat. No. 6,053,943 to Edwin et al.
• Like Jayararnan, U.S. Pat. No. 5,871,536 to Lazarus discloses a plurality of straight, longitudinal support structures 38 attached to thecircumferential support structures 36, see FIGS. 1, 6, 7, 8, 10, 11, 12, 14. FIG. 8 of Lazarus illustrates the longitudinal support structures 38 attached to adistal structure 36 and extending almost all of the way to theproximal structure 36. The longitudinal structures 38, 84, 94 can be directly connected to thebody 22, 80 and can be telescopic 38, 64.
• United States Patent Publication 2003/0088305 to Van Schie et al. (hereinafter “Van Schie”) does not disclose a support bar. Rather, it discloses a curved stent graft using an elastic material 8 connected to stents at aproximal end 2 and at a distal end 3 (see FIGS. 1, 2) thereof to create a curved stent graft. Because Van Schie needs to create a flexible curved graft, the elastic material 8 is made of silicone rubber or another similar material. Thus, the material 8 cannot provide support in the longitudinal extent of the stent graft. Accordingly, an alternative to the elastic support material 8 is a suture material 25 shown in FIGS. 3 to 6.
SUMMARY OF THE INVENTION
• The invention provides a delivery system and method for self-centering a proximal end of a stent graft that overcome the hereinafore-mentioned disadvantages of the heretofore-known devices and methods of this general type and that provides a vessel repair device that implants/conforms more efficiently within the natural or diseased course of the aorta by aligning with the natural curve of the aorta, decreases the likelihood of vessel puncture, increases the blood-tight vascular connection, retains the intraluminal wall of the vessel position, is more resistant to migration, and delivers the stent graft into a curved vessel while minimizing intraluminal forces imparted during delivery and while minimizing the forces needed for a user to deliver the stent graft into a curved vessel.
• With the foregoing and other objects in view, there is provided, in accordance with the invention, a method for implanting a prosthesis centrally within a curved lumen, including the steps of loading a prosthesis into a delivery sheath, the prosthesis having a proximal end and the sheath having a distal end, advancing the sheath in a patient towards the curved lumen to place at least the proximal end within the curved lumen, and centering the proximal end of the prosthesis and/or the distal end of the sheath within the curved lumen.
• With the objects of the invention in view, there is also provided a method for centrally implanting a prosthesis, including the steps of placing at least a proximal end of a prosthesis in a curved lumen of a patient and centering the proximal end of the prosthesis within the curved lumen before implanting the prosthesis therein.
• With the objects of the invention in view, there is also provided a method for implanting a prosthesis centrally within a curved lumen, including the steps of loading a prosthesis into a delivery sheath, the prosthesis having a proximal end and the sheath having a distal end, in a first advancing step, advancing the outer catheter containing the inner sheath together towards the curved lumen to a location proximal of the curved lumen, and, in a second advancing step, advancing the inner sheath containing the prosthesis into the curved lumen to place at least the proximal end within the curved lumen while the outer catheter substantially remains at the location, centering the proximal end of the prosthesis and/or the distal end of the sheath within the curved lumen, and, after carrying out the centering step, deploying the proximal end of the prosthesis centered within the curved lumen.
• With the objects of the invention in view, there is also provided a method of implanting a prosthesis in a patient at a treatment site, including the steps of providing a prosthesis delivery system with a relatively flexible inner sheath and a relatively stiff outer sheath, loading a prosthesis inside the inner sheath, loading the inner sheath containing the prosthesis within the outer sheath, advancing the outer sheath in a patient towards the treatment site up to a given position at a distance from the treatment site. While the outer sheath is retained in the given position, the inner sheath is advanced out from the outer sheath to the treatment site to place at least a proximal end of inner sheath within the treatment site and the proximal end of the prosthesis and/or the distal end of the inner sheath is centered within the curved lumen. The inner sheath is retracted to at least partially implant the prosthesis at the treatment site, and, upon completion of prosthesis implantation, both of the inner and outer sheaths are retracted out from the patient.
• In accordance with another mode of the invention, after carrying out the centering step, the prosthesis is deployed centered within the curved lumen.
• In accordance with a further mode of the invention, the proximal end of the prosthesis has an orifice defining an inflow plane and a proximal end implantation site of the lumen defines an implant plane, and the centering step is carried out by substantially aligning the inflow plane with the implant plane.
• In accordance with an added mode of the invention, after carrying out the centering step, the prosthesis is deployed with the inflow plane substantially aligned with the implant plane.
• In accordance with an additional mode of the invention, the centering step is carried out by centering at least the distal end of the sheath within the curved lumen with a sheath centering device.
• In accordance with an additional mode of the invention, the loading step is carried out by partially collapsing the prosthesis to a size smaller than an interior of the sheath and inserting the partially collapsed prosthesis into the sheath and the deployment step is carried out by releasing the prosthesis centered within the curved lumen.
• In accordance with yet a further mode of the invention, the sheath is provided as a relatively flexible inner sheath and the inner sheath is slidably disposed inside a relatively stiff outer catheter.
• In accordance with yet an added mode of the invention, the advancing step is carried out by first advancing the outer catheter containing the inner sheath together towards the curved lumen to a location proximal of the curved lumen and subsequently advancing the inner sheath containing the prosthesis into the curved lumen while the outer catheter substantially remains at the location.
• In accordance with yet an additional mode of the invention, the centering step is carried out within a curved portion of an aorta.
• In accordance with again another mode of the invention, the prosthesis is provided with a tubular graft body defining an inflow plane and an exit plane and all portions of the stents on the graft body are disposed between the inflow plane and the exit plane.
• In accordance with again a further mode of the invention, a guidewire is placed through an implantation site within the curved lumen, the advancing step is carried out by guiding the delivery sheath containing the prosthesis along the guidewire, and the centering step is carried out by moving the proximal end of the prosthesis and/or the distal end of the sheath in a direction away from the guidewire at the implantation site.
• In accordance with again an added mode of the invention, a tip is provided and the centering of the proximal end of the prosthesis is carried out with the tip.
• In accordance with again an additional mode of the invention, the tip is slidably disposed within the delivery sheath.
• In accordance with still a further mode of the invention, the tip is operatively connected to the delivery sheath to perform the centering step with the tip and the sheath.
• In accordance with still an added mode of the invention, a tip is slidably disposed within the delivery sheath to place the tip at the distal end of the sheath, a sheath centering device is connected to the tip through the sheath, and the centering step is carried out with the sheath centering device.
• In accordance with still an additional mode of the invention, a tip is provided with a sheath centering device, the tip is slidably disposed within the delivery sheath to place the tip at the distal end of the sheath, and the centering step is carried out by expanding the sheath centering device out from the tip.
• In accordance with another mode of the invention, a sheath centering device is provided at the proximal end of the sheath and the centering step is carried out with the sheath centering device.
• In accordance with still another mode of the invention, the centering step is carried out with a sheath centering device physically separate from the sheath.
• In accordance with yet another mode of the invention, before carrying out the centering step, a central axis of the sheath centering device is placed approximately orthogonal to a longitudinal axis of the sheath.
• In accordance with an additional mode of the invention, the centering step is carried out with a sheath centering device surrounding an exterior of the sheath.
• In accordance with again another mode of the invention, the centering step is carried out with a sheath centering device disposed between an exterior surface of the sheath and a wall of a lumen in which the sheath is present.
• In accordance with a concomitant mode of the invention, the centering step is carried out with a sheath centering device disposed within the sheath.
• Other features that are considered as characteristic for the invention are set forth in the appended claims.
• Although the invention is illustrated and described herein as embodied in a delivery system and method for self-centering a proximal end of a stent graft, it is, nevertheless, not intended to be limited to the details shown because various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
• The construction and method of operation of the invention, however, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
• The features of the present invention, which are believed to be novel, are set forth with particularity in the appended claims. The invention, together with further objects and advantages thereof, may best be understood by reference to the following description, taken in conjunction with the accompanying drawings, in the several figures of which like reference numerals identify like elements, and in which:
• FIG. 1 is a side elevational view of a stent graft according to the invention;
• FIG. 2 is a side elevational view of a stent of the stent graft ofFIG. 1;
• FIG. 3 is a cross-sectional view of the stent ofFIG. 2 with different embodiments of protrusions;
• FIG. 4 is a perspective view of a prior art round mandrel for forming prior art stents;
• FIG. 5 is a fragmentary, side elevational view of a prior art stent in a portion of a vessel;
• FIG. 6 is a perspective view of a dodecahedral-shaped mandrel for forming stents inFIGS. 1 to 3;
• FIG. 7 is a fragmentary, side elevational view of the stent ofFIGS. 1 to 3 in a portion of a vessel;
• FIG. 8 is a fragmentary, enlarged side elevational view of the proximal end of the stent graft ofFIG. 1 illustrating movement of a gimbaled end;
• FIG. 9 is a side elevational view of a two-part stent graft according to the invention;
• FIG. 10 is a fragmentary, side elevational view of a delivery system according to the invention with a locking ring in a neutral position;
• FIG. 11 is a fragmentary, side elevational view of the delivery system ofFIG. 10 with the locking ring in an advancement position and, as indicated by dashed lines, a distal handle and sheath assembly in an advanced position;
• FIG. 12 is a fragmentary, enlarged view of a sheath assembly of the delivery system ofFIG. 10;
• FIG. 13 is a fragmentary, enlarged view of an apex capture device of the delivery system ofFIG. 10 in a captured position;
• FIG. 14 is a fragmentary, enlarged view of the apex capture device ofFIG. 13 in a released position;
• FIG. 15 is a fragmentary, enlarged view of an apex release assembly of the delivery system ofFIG. 10 in the captured position;
• FIG. 16 is a fragmentary, enlarged view of the apex release assembly ofFIG. 15 in the captured position with an intermediate part removed;
• FIG. 17 is a fragmentary, enlarged view of the apex release assembly ofFIG. 16 in the released position;
• FIG. 18 is a fragmentary, side elevational view of the delivery system ofFIG. 11 showing how a user deploys the prosthesis;
• FIG. 19 is a fragmentary cross-sectional view of human arteries including the aorta with the assembly of the present invention in a first step of a method for inserting the prosthesis according to the invention;
• FIG. 20 is a fragmentary cross-sectional view of the arteries ofFIG. 19 with the assembly in a subsequent step of the method for inserting the prosthesis;
• FIG. 21 is a fragmentary cross-sectional view of the arteries ofFIG. 20 with the assembly in a subsequent step of the method for inserting the prosthesis;
• FIG. 22 is a fragmentary cross-sectional view of the arteries ofFIG. 21 with the assembly in a subsequent step of the method for inserting the prosthesis;
• FIG. 23 is a fragmentary cross-sectional view of the arteries ofFIG. 22 with the assembly15 in a subsequent step of the method for inserting the prosthesis;
• FIG. 24 is a fragmentary cross-sectional view of the arteries ofFIG. 23 with the assembly in a subsequent step of the method for inserting the prosthesis;
• FIG. 25 is a fragmentary, diagrammatic, perspective view of the coaxial relationship of delivery system lumen according to the invention;
• FIG. 26 is a fragmentary, cross-sectional view of the apex release assembly according to the invention;
• FIG. 27 is a fragmentary, side elevational view of the stent graft ofFIG. 1 with various orientations of radiopaque markers according to the invention;
• FIG. 28 is a fragmentary perspective view of the stent graft ofFIG. 1 with various orientations of radiopaque markers according to the invention;
• FIG. 29 is a perspective view of a distal apex head of the apex capture device ofFIG. 13;
• FIG. 30 is a fragmentary side elevational view of the distal apex head ofFIG. 29 and a proximal apex body of the apex capture device ofFIG. 13 with portions of a bare stent in the captured position;
• FIG. 31 is a fragmentary, side elevational view of the distal apex head and proximal apex body ofFIG. 30 with a portion of the proximal apex body cut away to illustrate the bare stent in the captured position;
• FIG. 32 is a fragmentary side elevational view of the distal apex head and proximal apex body ofFIG. 30 in the released position;
• FIG. 33 is a fragmentary, cross-sectional view of an embodiment of handle assemblies according to the invention;
• FIG. 34 is a cross-sectional view of a pusher clasp rotator of the handle assembly ofFIG. 33;
• FIG. 35 is a plan view of the pusher clasp rotator ofFIG. 34 viewed along line C-C;
• FIG. 36 is a plan and partially hidden view of the pusher clasp rotator ofFIG. 34 with a helix groove for a first embodiment of the handle assembly ofFIGS. 10,11, and18;
• FIG. 37 is a cross-sectional view of the pusher clasp rotator ofFIG. 36 along section line A-A;
• FIG. 38 is a plan and partially hidden view of the pusher clasp rotator ofFIG. 36;
• FIG. 39 is a cross-sectional view of the pusher clasp rotator ofFIG. 38 along section line B-B;
• FIG. 40 is a perspective view of a rotator body of the handle assembly ofFIG. 33;
• FIG. 41 is an elevational and partially hidden side view of the rotator body ofFIG. 40;
• FIG. 42 is a cross-sectional view of the rotator body ofFIG. 41 along section line A-A;
• FIG. 43 is an elevational and partially hidden side view of the rotator body ofFIG. 40;
• FIG. 44 is an elevational and partially hidden side view of a pusher clasp body of the handle assembly ofFIG. 33;
• FIG. 45 is a cross-sectional view of the pusher clasp body ofFIG. 44 along section line A-A;
• FIG. 46 is a cross-sectional view of the pusher clasp body ofFIG. 44 along section line B-B;
• FIG. 47 is a fragmentary, side elevational view of a portion of the handle assembly ofFIG. 33 with a sheath assembly according to the invention;
• FIG. 48 is an exploded side elevational view of a portion of the handle assembly ofFIG. 47;
• FIG. 49 is a fragmentary elevational and partially hidden side view of a handle body of15 the handle assembly ofFIG. 33;
• FIG. 50 is a fragmentary, exploded side elevational view of a portion of a second embodiment of the handle assembly according to the invention;
• FIG. 51 is a fragmentary, side elevational view of the portion ofFIG. 50 in a neutral position;
• FIG. 52 is an exploded view of a first portion of the second embodiment of the handle assembly;
• FIG. 53 is a fragmentary, exploded view of a larger portion of the second embodiment of the handle assembly as compared toFIG. 52 with the first portion and the sheath assembly;
• FIG. 54 is perspective view of a clasp body of the second embodiment of the handle assembly;
• FIG. 55 is an elevational side view of the clasp body ofFIG. 54;
• FIG. 56 is a cross-sectional view of the clasp body ofFIG. 55 along section line A-A;
• FIG. 57 is a plan view of the clasp body ofFIG. 54;
• FIG. 58 is a plan view of the clasp body ofFIG. 57 viewed from section line B-B;
• FIG. 59 is a fragmentary and partially hidden side elevational view of a clasp sleeve of the second embodiment of the handle assembly;
• FIG. 60 is a fragmentary, cross-sectional view of a portion the clasp sleeve ofFIG. 59 along section line A;
• FIG. 61 is a fragmentary, cross-sectional view of the clasp sleeve ofFIG. 59 along section line C-C;
• FIG. 62 is a fragmentary and partially hidden side elevational view of the clasp sleeve ofFIG. 59 rotated with respect toFIG. 59;
• FIG. 63 is a fragmentary, cross-sectional view of the nose cone and sheath assemblies ofFIG. 10;
• FIG. 64 is a fragmentary, perspective view of a portion of self-alignment configuration according to the invention;
• FIG. 65 is a diagrammatic, fragmentary, cross-sectional view of a distal portion of the delivery system with the self-alignment configuration according to the invention inside the descending thoracic aorta and with the self-alignment configuration in an orientation opposite a desired orientation;
• FIG. 66 is a diagrammatic, fragmentary, cross-sectional view of the distal portion of the delivery system ofFIG. 65 with the self-alignment configuration partially inside the descending thoracic aorta and partially inside the aortic arch and with the self-alignment configuration in an orientation closer to the desired orientation;
• FIG. 67 is a diagrammatic, fragmentary, cross-sectional view of the distal portion of the delivery system ofFIG. 65 with the self-alignment configuration primarily inside the aortic arch and with the self-alignment configuration substantially in the desired orientation;
• FIG. 68 is a fragmentary, enlarged, partially exploded perspective view of an alternative embodiment of a distal end of the graft push lumen ofFIG. 25;
• FIG. 69 is a photograph of a user bending a stent graft assembly around a curving device to impart a curve to a guidewire lumen therein;
• FIG. 70 is a side elevational view of a stent graft according to the invention;
• FIG. 71 is a side elevational view of an alternative embodiment of the stent graft with a clasping stent and a crown stent;
• FIG. 72 is a photograph depicting a side view of the stent graft ofFIG. 71;
• FIG. 73 is a photograph of a perspective view from a side of a proximal end of the stent graft ofFIGS. 1 and 70 with a bare stent protruding from the proximal end thereof;
• FIG. 74 is a photograph of an enlarged, perspective view from the interior of the proximal end of the stent graft ofFIG. 71;
• FIG. 75 is a photograph of a perspective view from a distal end of the stent graft ofFIG. 71 with an alternative embodiment of the crown stent where less of the stent is attached to the graft;
• FIG. 76 is a photograph of a side view of the stent graft ofFIG. 71 partially withdrawn from a flexible sheath of the delivery system according to the invention with some of the capture stent apices releasably held within the apex capture device of the delivery system.
• FIG. 77 is a photograph of a perspective view of the captured stent graft ofFIG. 76 from the proximal end thereof and with some of the capture stent apices releasably held within the apex capture device of the delivery system;
• FIG. 78 is a photograph of a perspective view from the proximal end of the stent graft ofFIGS. 1 and 70 deployed in an exemplary vessel;
• FIG. 79 is a photograph of a perspective view from the proximal end of the stent graft ofFIG. 71 deployed in an exemplary vessel;
• FIG. 80 is a cross-sectional view of the apex capture assembly ofFIGS. 13,14,29 to32, and63 along a plane orthogonal to the longitudinal axis of the delivery system according to the invention without the inner sheath;
• FIG. 81 is a fragmentary, cross-sectional view of the apex capture assembly ofFIG. 80 along a plane orthogonal to the view plane ofFIG. 80 and through the longitudinal axis of the delivery system according to the invention without the inner sheath;
• FIG. 82 is a fragmentary, side elevational view of a distal end of the delivery system according to the invention with the inner sheath in a curved orientation and having an alternative embodiment of a D-shaped marker thereon;
• FIG. 83 is a fragmentary, plan view of the distal end ofFIG. 82 viewed from above;
• FIG. 84 is a fragmentary, plan and partially hidden view of the distal end ofFIG. 82 viewed from below with the D-shaped marker on the opposite top side;
• FIG. 85 is a fragmentary, elevational view of the distal end ofFIG. 82 viewed from the top ofFIG. 82 and parallel to the longitudinal axis of the catheter of the delivery system;
• FIG. 86 is a side elevational view of the delivery system according to the invention with an alternative embodiment of a rotating distal handle;
• FIG. 87 is a fragmentary, cross-sectional view of the rotating distal handle ofFIG. 86;
• FIG. 88 is a is a fragmentary, cross-sectional view of an alternative embodiment of the rotating distal handle ofFIG. 86;
• FIG. 89 is a fragmentary, perspective view of the distal end of the delivery system ofFIG. 86;
• FIG. 90 is a perspective view from the distal side of another embodiment of the delivery system of the invention;
• FIG. 91 is a fragmentary, enlarged, exploded, side elevational view of the apex release assembly of the delivery system ofFIG. 90;
• FIG. 92 is a fragmentary, enlarged, partially exploded, side elevational view of the locking knob assembly of the delivery system ofFIG. 90;
• FIG. 93 is a perspective view of a clasp sleeve of a handle assembly of the delivery system ofFIG. 90;
• FIG. 94 is an exploded, perspective view of a clasp body assembly of the handle assembly ofFIG. 90;
• FIG. 95 is an exploded, perspective view of a rotator assembly of the handle assembly ofFIG. 90;
• FIG. 96 is a perspective view of the rotator assembly ofFIG. 95 in an assembled state;
• FIG. 97 is a fragmentary, exploded, side elevational view of a delivery sheath of the delivery system ofFIG. 90;
• FIG. 98 is a fragmentary, exploded, side elevational view of the delivery sheath ofFIG. 97 rotated approximately 90 degrees;
• FIG. 99 is an enlarged, side elevational view of a portion of the delivery sheath ofFIG. 98;
• FIG. 100 is a fragmentary, enlarged, side elevational view of the distal end of the delivery system ofFIG. 90;
• FIG. 101 is a fragmentary, partially hidden side elevational view and partially cross-sectional view of the proximal end of the handle assembly ofFIG. 90 with the sheath lumen removed;
• FIG. 102 is a fragmentary, cross-sectional view of the proximal end of the handle assembly ofFIG. 101;
• FIG. 103 is a fragmentary, enlarged, cross-sectional view of the actuation knob and clasp body assemblies of the handle assembly ofFIG. 102;
• FIG. 104 is a fragmentary, enlarged, cross-sectional view of the rotator assembly of the handle assembly ofFIG. 102;
• FIG. 105 is a fragmentary, further-enlarged, cross-sectional view of the rotator assembly of the handle assembly ofFIG. 104;
• FIG. 106 is a fragmentary, transverse cross-sectional view of the handle assembly of the delivery system ofFIG. 90;
• FIG. 107 is a fragmentary, transverse cross-sectional view of the handle assembly of the delivery system ofFIG. 90;
• FIG. 108 is a fragmentary, transverse cross-sectional view of the handle assembly of the delivery system ofFIG. 90;
• FIG. 109 is a fragmentary, transverse cross-sectional view of the handle assembly of the delivery system ofFIG. 90;
• FIG. 110 is a fragmentary, transverse cross-sectional view of the handle assembly of the delivery system ofFIG. 90;
• FIG. 111 is a fragmentary, enlarged, transverse cross-sectional view of the handle assembly ofFIG. 110;
• FIG. 112 is a fragmentary, transverse cross-sectional view of the handle assembly of the delivery system ofFIG. 90;
• FIG. 113 is a fragmentary, enlarged transverse cross-sectional view of the handle assembly ofFIG. 112;
• FIG. 114 is a fragmentary, transverse cross-sectional view of the handle assembly of the delivery system ofFIG. 90;
• FIG. 115 is a fragmentary, transverse cross-sectional view of the handle assembly of the delivery system ofFIG. 90;
• FIG. 116 is a fragmentary, transverse cross-sectional view of the handle assembly of the delivery system ofFIG. 90;
• FIG. 117 is a fragmentary, transverse cross-sectional view of the handle assembly of the delivery system ofFIG. 90;
• FIG. 118 is a fragmentary, transverse cross-sectional view of the handle assembly of the delivery system ofFIG. 90;
• FIG. 119 is a fragmentary, shaded, cross-sectional view of a distal portion of the handle assembly ofFIG. 90 without the proximal handle;
• FIG. 120 is a fragmentary, diagrammatic cross-sectional view of the thoracic aorta with a prior art stent graft having an inflow plane at an angle to an implant plane;
• FIG. 121 is a fragmentary, diagrammatic cross-sectional view of the thoracic aorta with a stent graft placed according to the invention with the inflow plane aligned with the implant plane;
• FIG. 122 is a diagrammatic, side elevational view of a first exemplary embodiment of a stent graft centering device according to the invention;
• FIG. 123 is a fragmentary, diagrammatic, cross-sectional view of the stent graft centering device ofFIG. 122 in an aorta;
• FIG. 124 is a fragmentary, diagrammatic, perspective view of a second exemplary embodiment of a stent graft centering device according to the invention;
• FIG. 125 is a fragmentary, diagrammatic, cross-sectional view of the stent graft centering device ofFIG. 124 with one balloon inflated in an aorta;
• FIG. 126 is a diagrammatic, plan view of the stent graft centering device ofFIG. 124 with three balloons inflated;
• FIG. 127 is a diagrammatic, hidden, perspective view of a fourth exemplary embodiment of a stent graft centering device according to the invention in a first position;
• FIG. 128 is a diagrammatic, hidden, perspective view of the stent graft centering device ofFIG. 127 in a second position;
• FIG. 129 is a fragmentary, diagrammatic, cross-sectional view of a fifth exemplary embodiment of a stent graft centering device according to the invention;
• FIG. 130 is a fragmentary, diagrammatic, cross-sectional illustration forces acting upon the stent graft centering device ofFIG. 129;
• FIG. 131 is a fragmentary, diagrammatic, cross-sectional view of a sixth exemplary20 embodiment of a stent graft centering device according to the invention in a first position;
• FIG. 132 is a fragmentary, diagrammatic, cross-sectional view of the stent graft centering device ofFIG. 131 in a second position;
• FIG. 133 is a fragmentary, diagrammatic, perspective view of a seventh exemplary embodiment of a stent graft centering device according to the invention in a closed position;
• FIG. 134 is a fragmentary, diagrammatic, perspective view of the stent graft centering device ofFIG. 133 in an open position;
• FIG. 135 is a fragmentary, diagrammatic, perspective view of the stent graft centering device ofFIG. 133 in captured state;
• FIG. 136 is a fragmentary, diagrammatic, side elevational view of an eighth exemplary embodiment of a stent graft centering device according to the invention;
• FIG. 137 is a fragmentary, diagrammatic, side elevational view of the stent graft centering device ofFIG. 136 in an extended state;
• FIGS. 138 and 140 is a fragmentary, diagrammatic, exploded view the stent graft centering device ofFIG. 136;
• FIG. 139 is a fragmentary, diagrammatic, side elevational view the stent graft centering device ofFIG. 136 in a retracted state with a stent captured;
• FIG. 141 is a fragmentary, diagrammatic, side elevational view the stent graft centering device ofFIG. 136 in an extended centering state with a stent captured;
• FIG. 142 is a fragmentary, diagrammatic, side elevational view the stent graft centering device ofFIG. 136 in an extended centering state with a stent released;
• FIG. 143 is a fragmentary, diagrammatic, cross-sectional view of an ninth exemplary embodiment of a stent graft centering device according to the invention in an aorta;
• FIG. 144 is a fragmentary, diagrammatic, side elevational view of a tenth exemplary embodiment of a stent graft centering device according to the invention in a straight orientation;
• FIG. 145 is a fragmentary, diagrammatic, side elevational view of the stent graft centering device ofFIG. 144 in a crooked orientation;
• FIG. 146 is a fragmentary, diagrammatic, side elevational view of the stent graft centering device ofFIG. 144 in a bent orientation;
• FIG. 147 is a fragmentary, diagrammatic, cross-sectional view of an eleventh exemplary embodiment of a stent graft centering device according to the invention in a centered orientation;
• FIG. 148 is a fragmentary, diagrammatic, cross-sectional view of the stent graft centering device ofFIG. 147 with a delivery system therein and a stent graft closed;
• FIG. 149 is a fragmentary, diagrammatic, cross-sectional view of the stent graft centering device ofFIG. 147 with a delivery system therein and a stent graft open;
• FIGS. 150 and 150A are fragmentary, diagrammatic, perspective views of the stent graft centering device ofFIG. 147 with balloons inflated.
• FIG. 151 is a fragmentary, diagrammatic, perspective view of the stent graft centering device ofFIG. 147 with balloons deflated;
• FIG. 152 is a fragmentary, diagrammatic, cross-sectional view of a twelfth exemplary embodiment of a stent graft centering device according to the invention in an aorta;
• FIG. 153 is a fragmentary, diagrammatic, cross-sectional view of the stent graft centering device ofFIG. 152 centering a stent graft delivery device with the stent graft closed;
• FIG. 154 is a fragmentary, diagrammatic, cross-sectional view of the stent graft centering device ofFIG. 152 centering a stent graft delivery device with the stent graft open;
• FIG. 155 is a fragmentary, diagrammatic, cross-sectional view of the stent graft centering device ofFIG. 152;
• FIG. 156 is a fragmentary, diagrammatic, side elevational view of a thirteenth exemplary embodiment of a stent graft centering device according to the invention;
• FIG. 157 is a fragmentary, diagrammatic, side elevational view of a prior art stent graft in an aorta having the inflow plane at an angle to the implant plane;
• FIG. 158 is a fragmentary, diagrammatic, side elevational view of the stent graft centering device ofFIG. 156 in an aorta having the inflow plane aligned with the implant plane;
• FIG. 159 is a fragmentary, diagrammatic, perspective view of a fourteenth exemplary embodiment of a stent graft centering device according to the invention;
• FIG. 160 is a fragmentary, diagrammatic, perspective view of a fifteenth exemplary embodiment of a stent graft centering device according to the invention;
• FIG. 161 is a fragmentary, diagrammatic, perspective view of a control assembly of the stent graft centering device ofFIG. 160;
• FIG. 162 is a fragmentary, diagrammatic, perspective view of a sixteenth exemplary embodiment of a stent graft centering device according to the invention in a first configuration;
• FIG. 163 is a fragmentary, diagrammatic, perspective view of the stent graft centering device ofFIG. 162 in a second configuration;
• FIG. 164 is a fragmentary, diagrammatic, side elevational view of a seventeenth exemplary embodiment of a stent graft centering device according to the invention in an expanded orientation;
• FIG. 165 is a fragmentary, diagrammatic, side elevational view of the stent graft centering device ofFIG. 164 in a further expanded orientation;
• FIG. 166 is a fragmentary, diagrammatic, side elevational view of the stent graft centering device ofFIG. 164 in a contracted orientation;
• FIG. 167 is a fragmentary, diagrammatic, side elevational view of the stent graft centering device ofFIG. 164 in an open position;
• FIG. 167A is a fragmentary, diagrammatic, enlarged side elevational view of a portion of the stent graft centering device ofFIG. 167 in the open position;
• FIG. 168 is a fragmentary, diagrammatic, enlarged, side elevational view of a portion of the stent graft centering device ofFIG. 164 in a captured position;
• FIG. 169 is a fragmentary, diagrammatic, side elevational view of the stent graft centering device ofFIG. 167 in a captured position of a stent;
• FIG. 170 is a fragmentary, diagrammatic, perspective view of an eighteenth exemplary embodiment of a stent graft centering device according to the invention in a closed orientation;
• FIG. 171 is a fragmentary, diagrammatic, perspective view of the stent graft centering device ofFIG. 110 through a stent graft;
• FIG. 172 is a fragmentary, diagrammatic, perspective view of the stent graft centering device ofFIG. 171 in an open orientation without the stent graft;
• FIG. 173 is a fragmentary, diagrammatic, side elevational view of a nineteenth exemplary embodiment of a stent graft centering device according to the invention in a closed orientation;
• FIG. 174 is a fragmentary, diagrammatic, side elevational view of the stent graft centering device ofFIG. 173 in an open orientation;
• FIG. 175 is a fragmentary, diagrammatic, side elevational view of the stent graft centering device ofFIG. 174 through a stent graft; and
• FIG. 176 is a fragmentary, diagrammatic, side elevational view of a twentieth exemplary embodiment of a stent graft centering device according to the invention.
DESCRIPTION OF EXEMPLARY EMBODIMENTS
• While the specification concludes with claims defining the features of the invention that are regarded as novel, it is believed that the invention will be better understood from a consideration of the following description in conjunction with the drawing figures, in which like reference numerals are carried forward.
• The present invention provides a stent graft, delivery system, and method for implanting a prosthesis with a two-part expanding delivery system that treats, in particular, thoracic aortic defects from the brachiocephalic level of the aortic arch distally to a level just superior to the celiac axis and provides an endovascular foundation for an anastomosis with the thoracic aorta, while providing an alternative method for partial/total thoracic aortic repair by excluding the vessel defect and making surgical repair of the aorta unnecessary. The stent graft of the present invention, however, is not limited to use in the aorta. It can be endoluminally inserted in any accessible artery that could accommodate the stent graft's dimensions.
Stent Graft
• The stent graft according to the present invention provides various features that, heretofore, have not been applied in the art and, thereby, provide a vessel repair device that implants/conforms more efficiently within the natural or diseased course of the aorta, decreases the likelihood of vessel puncture, and increases the blood-tight vascular connection, and decreases the probability of graft mobility.
• The stent graft is implanted endovascularly before or during or in place of an open repair of the vessel (i.e., an arch, in particular, the ascending and/or descending portion of the aorta) through a delivery system described in detail below. The typical defects treated by the stent graft are aortic aneurysms, aortic dissections, and other diseases such as penetrating aortic ulcer, coarctation, and patent ductus arteriosus, related to the aorta. When endovascularly placed in the aorta, the stent graft forms a seal in the vessel and automatically affixes itself to the vessel with resultant effacement of the pathological lesion.
• Referring now to the figures of the drawings in detail and first, particularly toFIG. 1 thereof, there is shown an improved stent graft1 having agraft sleeve10 and a number ofstents20. Thesestents20 are, preferably, made of nitinol, an alloy having particularly special properties allowing it to rebound to a set configuration after compression, the rebounding property being based upon the temperature at which the alloy exists. For a detailed explanation of nitinol and its application with regard to stents, see, e.g., U.S. Pat. Nos. 4,665,906, 5,067,957, and 5,597,378 to Jervis and to Gianturco.
• Thegraft sleeve10 is cylindrical in shape and is made of a woven graft material along its entire length. The graft material is, preferably, polyester, in particular, polyester referred to under the name DACRON® or other material types like Expanded Polytetrafluoroethylene (“EPTFE”), or other polymeric based coverings. Thetubular graft sleeve10 has a framework of individual lumen-supporting wires each referred to in the art as astent20. Connection of eachstent20 is, preferably, performed by sewing a polymeric (nylon, polyester) thread around an entirety of thestent20 and through thegraft sleeve10. The stitch spacings are sufficiently close to prevent any edge of thestent20 from extending substantially further from the outer circumference of thegraft sleeve10 than the diameter of the wire itself. Preferably, the stitches have a 0.5 mm to 5 mm spacing.
• Thestents20 are sewn either to the exterior or interior surfaces of thegraft sleeve10.FIG. 1 illustrates allstents20,30 on the exterior surface16 of thegraft sleeve10. In an exemplary non-illustrated embodiment, the most proximal23 and distal stents and abare stent30 are connected to the interior surface of thegraft sleeve10 and the remainder of thestents20 are connected to the exterior surface16. Another possible non-illustrated embodiment alternates connection of thestents20,30 to thegraft sleeve10 from the graft exterior surface to the graft interior surface, the alternation having any periodic sequence.
• Astent20, when connected to thegraft sleeve10, radially forces thegraft sleeve10 open to a predetermined diameter D. The released radial force creates a seal with the vessel wall and affixes the graft to the vessel wall when the graft is implanted in the vessel and is allowed to expand.
• Typically, thestents20 are sized to fully expand to the diameter D of the fully expandedgraft sleeve10. However, a characteristic of the present invention is that each of thestents20 and30 has a diameter larger than the diameter D of the fully expandedgraft sleeve10. Thus, when the stent graft1 is fully expanded and resting on the internal surface of the vessel where it has been placed, eachstent20 is imparting independently a radially directed force to thegraft sleeve10. Such pre-compression, as it is referred to herein, is applied (1) to ensure that the graft covering is fully extended, (2) to ensure sufficient stent radial force to make sure sealing occurs, (3) to affix the stent graft and prevent it from kinking, and (4) to affix the stent graft and prevent migration.
• Preferably, each of thestents20 is formed with a single nitinol wire. Of course other biocompatible materials can be used, for example, stainless steel, biopolymers, cobalt chrome, and titanium alloys.
• An exemplary shape of eachstent20 corresponds to what is referred in the art as a Z-stent, see, e.g., Gianturco (although the shape of thestents20 can be in any form that satisfies the functions of a self-expanding stent). Thus, the wire forming thestent20 is a ring having a wavy or sinusoidal shape. In particular, an elevational view orthogonal to the center axis21 of thestent20 reveals a shape somewhere between a triangular wave and a sinusoidal wave as shown inFIG. 2. In other words, the view ofFIG. 2 shows that thestents20 each have alternating proximal22 and distal24 apices. Preferably, the apices have a radius r that does not present too great of a point towards a vessel wall to prevent any possibility of puncturing the vessel, regardless of the complete circumferential connection to thegraft sleeve10. In particular, the radius r of curvature of the proximal22 and distal24 apices of thestent20 are, preferably, equal. The radius of curvature r is between approximately 0.1 mm and approximately 3.0 mm, in particular, approximately 0.5 rom.
• Another advantageous feature of a stent lies in extending the longitudinal profile along which the stent contacts the inner wall of a vessel. This longitudinal profile can be explained with reference toFIGS. 3 to 7.
• Prior art stents and stents according to the present invention are formed on mandrels29,29′ by winding the wire around the mandrel29,29′ and forming theapexes22,24,32,34 by wrapping the wire over non-illustrated pins that protrude perpendicular from the axis of the mandrel. Such pins, if illustrated, would be located in the holes illustrated in the mandrels29,29′ ofFIGS. 4 and 6. Prior art stents are formed on a round mandrel29 (also referred to as a bar). Astent20′ formed on a round mandrel29 has a profile that is rounded (seeFIG. 5). Because of the rounded profile, thestent20′ does not conform evenly against the inner wall of thevessel2 in which it is inserted. This disadvantage is critical in the area of stent graft1 seal zones—areas where the ends of thegraft10 need to be laid against the inner wall of thevessel2. Clinical experience reveals thatstents20′ formed with the round mandrel29 do not lie against thevessel2; instead, only a mid-section of thestent20′ rests against thevessel2, as shown inFIG. 5. Accordingly, when such astent20′ is present at either of the proximal12 or distal14 ends of the stent graft1, the graft material flares away from the wall of thevessel2 into the lumen—a condition that is to be avoided. An example of this flaring can be seen by comparing the upper and lower portions of the curved longitudinal profile of thestent20′ inFIG. 5 with the linear longitudinal profile of thevessel2.
• To remedy this problem and ensure co-columnar apposition of the stent and vessel,stents20 of the present invention are formed on a multiple-sided mandrel. In particular, thestents20 are formed on a polygonal-shaped mandrel29′. The mandrel29′ does not have sharp edges. Instead, it has flat sections and rounded edge portions between the respective flat sections. Thus, a stent formed on the mandrel29′ will have a cross-section that is somewhat round but polygonal, as shown inFIG. 3. The cross-sectional view orthogonal to the center axis21 of such astent20 will have beveled or rounded edges31 (corresponding to the rounded edge portions of the mandrel29′) disposed between flat sides or struts33 (corresponding to the flat sections of the mandrel29′).
• To manufacture thestent20, apexes of thestents20 are formed by winding the wire over non-illustrated pins located on the rounded portions of the mandrel29′. Thus, thestruts33 lying between theapexes22,24,32,34 of thestents20 lie flat against the flat sides of the mandrel29′. When so formed on the inventive mandrel29′, the longitudinal profile is substantially less rounded than the profile ofstent20′ and, in practice, is substantially linear.
• Forstents20 having six proximal22 and six distal24 apices, thestents20 are formed on a dodecahedron-shaped mandrel29′ (a mandrel having twelve sides), which mandrel29′ is shown inFIG. 6. Astent20 formed on such a mandrel29′ will have the cross-section illustrated inFIG. 3.
• The fourteen-apex stent20 shown inFIG. 7 illustrates astent20 that has been formed on a fourteen-sided mandrel. Thestent20 inFIG. 7 is polygonal in cross-section (having fourteen sides) and, as shown inFIG. 7, has a substantially linear longitudinal profile. Clinically, the linear longitudinal profile improves the stent's20 ability to conform to thevessel2 and press thegraft sleeve10 outward in the sealing zones at the extremities of theindividual stent20.
• Another way to improve the performance of the stent graft1 is to provide the distal-most stent25 on the graft10 (i.e., downstream) with additional apices and to give it a longer longitudinal length (i.e., greater amplitude) and/or a longer circumferential length. When a stent25 having a longer circumferential length is sewn to a graft, the stent graft1 will perform better clinically. The improvement, in part, is due to a need for the distal portion of thegraft material10 to be pressed firmly against the wall of the vessel. The additional apices result in additional points of contact between the stent graft1 and vessel wall, thus ensuring better apposition to the wall of the vessel and better sealing of thegraft material10 to the vessel. The increased apposition and sealing substantially improves the axial alignment of thedistal end14 of the stent graft1 to the vessel. As set forth above, each of thestents20 and30 has a diameter larger than the diameter D of the fully expandedgraft sleeve10. Thus, if the distal stent25 also has a diameter larger than the diameter D, it will impart a greater radial bias on all 360 degrees of the corresponding section of the graft than stents not having such an oversized configuration.
• A typical implanted stent graft1 typically does not experience a lifting off at straight portions of a vessel because the radial bias of the stents acting upon the graft sleeve give adequate pressure to align the stent and graft sleeve with the vessel wall. However, when a typical stent graft is implanted in a curved vessel (such as the aorta), the distal end of the stent graft1 does experience a lift off from the vessel wall. The increased apposition and sealing of the stent graft1 according to the present invention substantially decreases the probability of lift off because the added height and additional apices enhance the alignment of the stent graft perpendicular to the vessel wall as compared to prior art stent grafts (no lift off occurs).
• The number of total apices of a stent is dependent upon the diameter of the vessel in which the stent graft1 is to be implanted. Vessels having a smaller diameter have a smaller total number of apices than a stent to be implanted in a vessel having a larger diameter. Table 1 below indicates exemplary stent embodiments for vessels having different diameters. For example, if a vessel has a 26 or 27 mm diameter, then an exemplary diameter of thegraft sleeve10 is 30 mm. For a 30 mm diameter graft sleeve, theintermediate stents20 will have 5 apices on each side (proximal and distal) for a total of 10 apices. In other words, the stent defines 5 periodic “waves.” The distal-most stent25, in comparison, defines 6 periodic “waves” and, therefore, has 12 total apices. It is noted that the distal-most stent25 inFIG. 1 does not have the additional apex. While Table 1 indicates exemplary embodiments, these configurations can be adjusted or changed as needed.

• TABLE 1
  Vessel Diameter	Graft Diameter	Stent Apices/Side
  (mm)	(mm)	(Distal-most Stent #)
  19	22	5(5)
  20-21	24	5(5)
  22-23	26	5(5)
  24-25	28	5(6)
  26-27	30	5(6)
  28-29	32	6(7)
  30-31	34	6(7)
  32-33	36	6(7)
  34	38	6(7)
  35-36	40	7(8)
  37-38	42	7(8)
  39-40	44	7(8)
  41-42	46	7(8)

• To increase the security of the stent graft1 in a vessel, an exposed orbare stent30 is provided on the stent graft1, preferably, only at theproximal end12 of thegraft sleeve10—proximal meaning that it is attached to the portion of thegraft sleeve10 from which the blood flows into the sleeve, i.e., blood flows from thebare stent30 and through thesleeve10 to the left ofFIG. 1. Thebare stent30 is not limited to being attached at theproximal end12. Another non-illustrated bare stent can be attached similarly to thedistal end14 of thegraft sleeve10.
• Significantly, thebare stent30 is only partially attached to thegraft sleeve10. Specifically, thebare stent30 is fixed to thegraft sleeve10 only at thedistal apices34 of thebare stent30. Thus, thebare stent30 is partially free to extend theproximal apices32 away from the proximal end of thegraft sleeve10.
• Thebare stent30 has various properties, the primary one being to improve the apposition of the graft material to the contour of the vessel wall and to align the proximal portion of the graft covering in the lumen of the arch and provide a blood-tight closure of theproximal end12 of thegraft sleeve10 so that blood does not pass between the vascular inside wall and outer surface16 of the sleeve10 (endoleak).
• An exemplary configuration for the radius of curvature a of thedistal apices34 is substantially equal to the radius r of the proximal22 and distal24 apices of thestent20, in particular, it is equal at least to the radius of curvature r of the proximal apices of thestent20 directly adjacent thebare stent30. Thus, as shown inFIG. 8, a distance between theproximal apices22 of the mostproximal stent23 and crossing points of the exposed portions of thebare stent30 are substantially at a same distance from one another all the way around the circumference of theproximal end12 of thegraft sleeve10. Preferably, this distance varies based upon the graft diameter. Accordingly, the sinusoidal portion of thedistal apices34 connected to thegraft sleeve10 traverse substantially the same path as that of thestent23 closest to thebare stent30. Thus, the distance d between thestent22 and all portions of thebare stent30 connected to thegraft sleeve10 remain constant. Such a configuration is advantageous because it maintains the symmetry of radial force of the device about the circumference of the vessel and also aids in the synchronous, simultaneous expansion of the device, thus increasing apposition of the graft material to the vessel wall to induce a proximal seal—and substantially improve the proximal seal—due to increasing outward force members in contact with the vessel wall.
• Inter-positioning thestents23,30 in phase with one another, creates an overlap, i.e., theapices34 of thebare stent30 are positioned within the troughs of thestent23. A further advantage of such a configuration is that the overlap provides twice as many points of contact between the proximal opening of thegraft10 and the vessel in which the stent graft1 is implanted. The additional apposition points keep the proximal opening of thegraft sleeve10 open against the vessel wall, which substantially reduces the potential for endoleaks. In addition, the overlap of thestents23,30 increases the radial load or resistance to compression, which functionally increases fixation and reduces the potential for device migration.
• In contrast to thedistal apices34 of thebare stent30, the radius of curvature β of the proximal apices32 (those apices that are not sewn into the graft sleeve10) is significantly larger than the radius of curvature a of thedistal apices34. An exemplary configuration for the bare stent apices has a radius approximately equal to 1.5 mm for theproximal apices32 and approximately equal to 0.5 mm for thedistal apices34. Such a configuration substantially prevents perforation of the blood vessel by theproximal apices32, or, at a minimum, makes is much less likely for thebare stent30 to perforate the vessel because of the less-sharp curvature of theproximal apices32.
• Thebare stent30 also has an amplitude greater than theother stents20. Preferably, the peak-to-peak amplitude of thestents20 is approximately 1.3 cm to 1.5 cm, whereas the peak-to-peak amplitude of thebare stent30 is approximately 2.5 cm to 4.0 cm. Accordingly, the force exerted by thebare stent30 on the inner wall of the aorta (due to thebare stent30 expanding to its native position) is spread over a larger surface area. Thus, thebare stent30 of the present invention presents a less traumatic radial stress to the interior of the vessel wall—a characteristic that, while less per square mm than an individual one of thestents20 would be, is sufficient, nonetheless, to retain theproximal end12 in position. Simultaneously, the taller configuration of thebare stent30 guides the proximal opening of the stent graft in a more “squared-off” manner. Thus, the proximal opening of the stent graft is more aligned with the natural curvature of the vessel in the area of the proximal opening.
• As set forth above, because the vessel moves constantly, and due to the constantly changing pressure imparted by blood flow, any stent graft placed in the vessel has the natural tendency to migrate downstream. This is especially true when the stent graft1 hasgraft sleeve segments18 with lengths defined by the separation of the stents on either end of thesegment18, giving the stent graft1 an accordion, concertina, or caterpillar-like shape. When such a shape is pulsating with the vessel and while hemodynamic pressure is imparted in a pulsating manner along the stent graft from theproximal end12 to the downstreamdistal end14, the stent graft1 has a tendency to migrate downstream in the vessel. It is desired to have such motion be entirely prohibited.
• Support along a longitudinal extent of thegraft sleeve10 assists in preventing such movement. Accordingly, as set forth above, prior art stent grafts have provided longitudinal15 rods extending in a straight line from one stent to another.
• The present invention, however, provides a longitudinal, spiraling/helical support member40 that, while extending relatively parallel to the longitudinal axis11 of thegraft sleeve10, is not aligned substantially parallel to a longitudinal extent of the entirety of the stent graft1 as done in the prior art. “Relatively parallel” is referred to herein as an extent that is more along the longitudinal axis11 of the stent graft1 than along an axis perpendicular thereto.
• Specifically, thelongitudinal support member40 has a somewhat S-turn shape, in that, a proximal portion42 is relatively parallel to the axis11 of thegraft sleeve10 at a first degree41 (being defined as a degree of the 360 degrees of the circumference of the graft sleeve10), and a distal portion44 is, also, relatively parallel to the axis11 of the tube graft, but at a different second degree43 on the circumference of thegraft sleeve10. The difference between the first and second degrees41,43 is dependent upon the length L of thegraft sleeve10. For an approximately 20 cm (approx. 8″) graft sleeve, for example, the second degree43 is between 80 and 110 degrees away from the first degree41, in particular, approximately 90 degrees away. In comparison, for an approximately 9 cm (approx. 3.5″) graft sleeve, the second degree43 is between 30 and 60 degrees away from the first degree41, in particular, approximately 45 degrees away. As set forth below, the distance between the first and second degrees41,43 is also dependent upon the curvature and the kind of curvature that the stent graft1 will be exposed to when in vivo.
• Thelongitudinal support member40 has a curved intermediate portion46 between the proximal and distal portions42,44. By using the word “portion” it is not intended to mean that the rod is in three separate parts (of course, in a particular configuration, a multi-part embodiment is possible). An exemplary embodiment of thelongitudinal support member40 is a single, one-piece rod made of stainless steel, cobalt chrome, nitinol, or polymeric material that is shaped as a fully curved helix42,44,46 without any straight portion. In an alternative stent graft embodiment, the proximal and distal portions42,44 can be substantially parallel to the axis11 of the stent graft1 and the central portion46 can be helically curved.
• One way to describe an exemplary curvature embodiment of thelongitudinal support member40 can be using an analogy of asymptotes. If there are two asymptotes extending parallel to the longitudinal axis11 of thegraft sleeve10 at the first and second degrees41,43 on thegraft sleeve10, then the proximal portion42 can be on the first degree41 or extend approximately asymptotically to the first degree41 and the distal portion44 can be on the second degree43 or extend approximately asymptotically to the second degree43. Because thelongitudinal support member40 is one piece in an exemplary embodiment, the curved portion46 follows the natural curve formed by placing the proximal and distal portions42,44 as set forth herein.
• In such a position, the curvedlongitudinal support member40 has a centerline45 (parallel to the longitudinal axis11 of thegraft sleeve10 halfway between the first and second degrees41,43 on the graft sleeve10). In this embodiment, therefore, the curved portion intersects thecenterline45 at approximately 20 to 40 degrees in magnitude, preferably at approximately 30 to 35 degrees.
• Another way to describe the curvature of the longitudinal support member can be with respect to thecenterline45. The portion of thelongitudinal support member40 between the first degree41 and thecenterline45 is approximately a mirror image of the portion of thelongitudinal support member40 between the second degree43 and thecenterline45, but rotated one-hundred eighty degrees (180°) around an axis orthogonal to thecenterline45. Such symmetry can be referred to herein as “reverse-mirror symmetrical.”
• Thelongitudinal support member40 is, preferably, sewn to thegraft sleeve10 in the same way as thestents20. However, thelongitudinal support member40 is not sewn directly to any of thestents20 in the proximal portions of the graft. In other words, thelongitudinal support member40 is independent of the proximal skeleton formed by thestents20. Such a configuration is advantageous because an independent proximal end creates a gimbal that endows the stent graft with additional flexibility. Specifically, the gimbaled proximal end allows the proximal end to align better to the proximal point of apposition, thus reducing the chance for endoleak. The additional independence from the longitudinal support member allows the proximal fixation point to be independent from the distal section that is undergoing related motion due to the physiological motion of pulsutile flow of blood. Also in an exemplary embodiment, thelongitudinal support member40 is pre-formed in the desired spiral/helical shape (counter-clockwise from proximal to distal), before being attached to thegraft sleeve10.
• Because vessels receiving the stent graft1 are not typically straight (especially the aortic arch), the final implanted position of the stent graft1 will, most likely, be curved in some way. In prior art stent grafts (which only provide longitudinally parallel support rods), there exist, inherently, a force that urges the rod, and, thereby, the entire stent graft, to the straightened, natural shape of the rod. This force is disadvantageous for stent grafts that are to be installed in an at least partly curved manner.
• The curved shape of thelongitudinal support member40 according to the present invention eliminates at least a majority, or substantially all, of this disadvantage because the longitudinal support member's40 natural shape is curved. Therefore, thesupport member40 imparts less of a force, or none at all, to straighten thelongitudinal support member40, and, thereby, move the implanted stent graft in an undesirable way. At the same time, the curvedlongitudinal support member40 negates the effect of the latent kinetic force residing in the aortic wall that is generated by the propagation of the pulse wave and systolic blood pressure in the cardiac cycle, which is, then, released during diastole. As set forth in more detail below, the delivery system of the present invention automatically aligns the stent graft1 to the most optimal position while traversing the curved vessel in which it is to be implanted, specifically, thelongitudinal support member40 is placed substantially at the superior longitudinal surface line of the curved aorta (with respect to anatomical position).
• In an exemplary embodiment, thelongitudinal support member40 can be curved in a patient-customized way to accommodate the anticipated curve of the actual vessel in which the graft will be implanted. Thus, the distance between the first and second degrees41,43 will be dependent upon the curvature and the kind of curvature that the stent graft1 will be exposed to when in vivo. As such, when implanted, the curvedlongitudinal support member40 will, actually, exhibit an opposite force against any environment that would alter its conformance to the shape of its resident vessel's existing course(es).
• Preferably, thesupport member40 is sewn, in a similar manner as thestents20, on the 5 outside surface16 of thegraft sleeve10.
• In prior art support rods, the ends thereof are merely a terminating end of a steel or nitinol rod and are, therefore, sharp. Even though these ends are sewn to the tube graft in the prior art, the possibility of tearing the vessel wall still exists. It is, therefore, desirable to not provide the support rod with sharp ends that could puncture the vessel in which the stent graft is placed.
• The two ends of thelongitudinal support member40 of the present invention do not end abruptly. Instead, each end of the longitudinalsupport member loops47 back upon itself such that the end of the longitudinal support member along the axis of the stent graft is not sharp and, instead, presents an exterior of a circular or oval shape when viewed from theends12,14 of thegraft sleeve10. Such a configuration substantially prevents the possibility of tearing the vessel wall and also provides additional longitudinal support at the oval shape by having two longitudinally extending sides of the oval47.
• In addition, in another embodiment, the end of the longitudinal support member may be connected to the secondproximal stent28 and to the most distal stent. This configuration would allow the longitudinal support member to be affixed to stent28 (seeFIG. 1) and the most distal stent for support while still allowing for the gimbaled feature of the proximal end of the stent graft to be maintained.
• A significant feature of thelongitudinal support member40 is that the ends of thelongitudinal support member40 may not extend all the way to the two ends12,14 of thegraft sleeve10. Instead, thelongitudinal support member40 terminates at or prior to the second-to-last stent28 at theproximal end12, and, if desired, prior to the second-to-last stent28′ at thedistal end14 of thegraft sleeve10. Such an ending configuration (whether proximal only or both proximal and distal) is chosen for a particular reason—when thelongitudinal support member40 ends before either of the planes defined bycross-sectional lines52,52′, thesleeve10 and thestents20 connected thereto respectively formgimbaled portions50,50′. In other words, when a grasping force acting upon the gimbaled ends50,50′ moves or pivots the cross-sectional plane defining each end opening of thegraft sleeve10 about the longitudinal axis11 starting from the planes defined by thecross-sectional lines52,52′, then the movingportions50,50′ can be oriented at any angle γ about the center of the circular opening in all directions (360 degrees), as shown inFIG. 8. The natural gimbal, thus, allows the ends50,50′ to be inclined in any radial direction away from the longitudinal axis11.
• Among other things, the gimbaled ends50,50′ allow each end opening to dynamically align naturally to the curve of the vessel in which it is implanted. A significant advantage of the gimbaled ends50,50′ is that they limit propagation of the forces acting upon the separate parts. Specifically, a force that, previously, would act upon the entirety of the stent graft1, in other words, both theend portions50,50′ and the middle portion of the stent graft1 (i.e., betweenplanes52,52′), now principally acts upon the portion in which the force occurs. For example, a force that acts only upon one of theend portions50,50′ substantially does not propagate into the middle portion of the stent graft1 (i.e., betweenplanes52,52′). More significantly, however, when a force acts upon the middle portion of the stent graft1 (whether moving longitudinally, axially (dilation), or in a torqued manner), the ends50,50′, because they are gimbaled, remain relatively completely aligned with the natural contours of the vessel surrounding therespective end50,′50′ and have virtually none of the force transferred thereto, which force could potentially cause the ends to grate, rub, or shift from their desired fixed position in the vessel. Accordingly, the stent graft ends50,50′ remain fixed in the implanted position and extend the seating life of the stent graft1.
• Another advantage of thelongitudinal support member40 is that it increases the columnar strength of the graft stent1. Specifically, the material of the graft sleeve can be compressed easily along the longitudinal axis11, a property that remains true even with the presence of thestents20 so long as thestents20 are attached to thegraft sleeve10 with a spacing between thedistal apices24 of onestent20 and theproximal apices22 of the nextadjacent stent20. This is especially true for the amount of force imparted by the flow of blood along the extent of the longitudinal axis11. However, with thelongitudinal support member40 attached according to the present invention, longitudinal strength of the stent graft1 increases to overcome the longitudinal forces imparted by blood flow.
• Another benefit imparted by having such increased longitudinal strength is that the stent graft1 is further prevented from migrating in the vessel because the tube graft is not compressing and expanding in an accordion-like manner—movement that would, inherently, cause graft migration.
• A further measure for preventing migration of the stent graft1 is to equip at least one of any of theindividual stents20,30 or thelongitudinal support member40 withprotuberances60, such as barbs or hooks (FIG. 3). See, e.g., United States Patent Publication 2002/0052660 to Greenhalgh. In an exemplary embodiment of the present invention, thestents20,30 are secured to the outer circumferential surface16 of thegraft sleeve10. Accordingly, if the stents20 (or connected portions of stent30) haveprotuberances60 protruding outwardly, then such features would catch the interior wall of the vessel and add to the prevention of stent graft1 migration. Such an embodiment can be preferred for aneurysms but is not preferred for the fragile characteristics of dissections becausesuch protuberances60 can excoriate the inner layer(s) of the vessel and cause leaks between layers, for example.
• As shown inFIG. 9, the stent graft1 is not limited to asingle graft sleeve10. Instead, the entire stent graft can be afirst stent graft100 having all of the features of the stent graft1 described above and asecond stent graft200 that, instead of having a circular extremeproximal end12, as set forth above, has aproximal end212 with a shape following the contour of the mostproximal stent220 and is slightly larger in circumference than the distal circumference of thefirst stent graft100. Therefore, an insertion of theproximal end212 of thesecond stent graft200 into thedistal end114 of thefirst stent graft100 results, in total, in a two-part stent graft. Because blood flows from the proximal end112 of thefirst stent graft100 to thedistal end214 of thesecond stent graft200, it is preferable to have thefirst stent graft100 fit inside thesecond stent graft200 to prevent blood from leaking out therebetween. This configuration can be achieved by implanting the devices in reverse order (first implant graft200 and, then,implant graft100. Each of thestent grafts100,200 can have its ownlongitudinal support member40 as needed.
• It is not significant if the stent apices of the distal-most stent of thefirst stent graft100 are not aligned with the stent apices of theproximal-most stent220 of thesecond stent graft200. What is important is the amount of junctional overlap between the twografts100,200.
Delivery System
• As set forth above, the prior art includes many different systems for endoluminally delivering a prosthesis, in particular, a stent graft, to a vessel. Many of the delivery systems have similar parts and most are guided along a guidewire that is inserted, typically, through an insertion into the femoral artery near a patient's groin prior to use of the delivery system. To prevent puncture of the arteries leading to and including the aorta, the delivery system is coaxially connected to the guidewire and tracks the course of the guidewire up to the aorta. The parts of the delivery system that will track over the wire are, therefore, sized to have an outside diameter smaller than the inside diameter of the femoral artery of the patient. The delivery system components that track over the guidewire include the stent graft and are made of a series of coaxial lumens referred to as catheters and sheaths. The stent graft is constrained, typically, by an outer catheter, requiring the stent graft to be compressed to fit inside the outer catheter. Doing so makes the portion of the delivery system that constrains the stent graft very stiff, which, therefore, reduces that portion's flexibility and makes it difficult for the delivery system to track over the guidewire, especially along curved vessels such as the aortic arch. In addition, because the stent graft exerts very high radial forces on the constraining catheter due to the amount that it must be compressed to fit inside the catheter, the process of deploying the stent graft by sliding the constraining catheter off of the stent graft requires a very high amount of force, typically referred to as a deployment force. Also, the catheter has to be strong enough to constrain the graft, requiring it to be made of a rigid material. If the rigid material is bent, such as when tracking into the aortic arch, the rigid material tends to kink, making it difficult if not impossible to deploy the stent graft.
• Common features of vascular prosthesis delivery systems include a tapered nose cone fixedly connected to a guidewire lumen, which has an inner diameter substantially corresponding to an outer diameter of the guidewire such that the guidewire lumen slides easily over and along the guidewire. A removable, hollow catheter covers and holds a compressed prosthesis in its hollow and the catheter is fixedly connected to the guidewire lumen. Thus, when the prosthesis is in a correct position for implantation, the physician withdraws the hollow catheter to gradually expose the self-expanding prosthesis from its proximal end towards its distal end. When the catheter has withdrawn a sufficient distance from each portion of the expanding framework of the prosthesis, the framework can expand to its native position, preferably, a position that has a diameter at least as great as the inner diameter of the vessel wall to, thereby, tightly affix the prosthesis in the vessel When the catheter is entirely withdrawn from the prosthesis and, thereby, allows the prosthesis to expand to the diameter of the vessel, the prosthesis is fully expanded and connected endoluminally to the vessel along the entire extent of the prosthesis, e.g., to treat a dissection. When treating an aneurysm, for example, the prosthesis is in contact with the vessel's proximal and distal landing zones when completely released from the catheter. At such a point in the delivery, the delivery system can be withdrawn from the patient. The prosthesis, however, cannot be reloaded in the catheter if implantation is not optimal.
• The aorta usually has a relatively straight portion in the abdominal region and in a lower part of the thoracic region. However, in the upper part of the thoracic region, the aorta is curved substantially, traversing an upside-down U-shape from the back of the heart over to the front of the heart. As explained above, prior art delivery systems are relatively hard and inflexible (the guidewire/catheter portion of the prior art delivery systems). Therefore, if the guidewire/catheter must traverse the curved portion of the aorta, it will kink as it is curved or it will press against the top portion of the aortic curve, possibly puncturing the aorta if the diseased portion is located where the guidewire/catheter is exerting its force. Such a situation must be avoided at all costs because the likelihood of patient mortality is high. The prior art does not provide any way for substantially reducing the stress on the curved portion of the aorta or for making the guidewire/catheter sufficiently flexible to traverse the curved portion without causing damage to the vessel.
• The present invention, however, provides significant features not found in the prior art that assist in placing a stent graft in a curved portion of the aorta in a way that substantially reduces the stress on the curved portion of the aorta and substantially reduces the insertion forces needed to have the compressed graft traverse the curved portion of the aorta. As set forth above, thelongitudinal support member40 is pre-formed in a desired spiral/helical shape before being attached to thegraft sleeve10 and, in an exemplary embodiment, is curved in a patient-customized way to accommodate the anticipated curve of the actual vessel in which the graft will be implanted. As such, optimal positioning of the stent graft1 occurs when thelongitudinal support member40 is placed substantially at the superior longitudinal surface line of the curved aorta (with respect to anatomical position). Such placement can be effected in two ways. First, the stent graft1, thesupport member40, or any portion of the delivery system that is near the target site can be provided with radiopaque markers that are monitored by the physician and used to manually align thesupport member40 in what is perceived as an optimal position. The success of this alignment technique, however, is dependent upon the skill of the physician. Second, the delivery system can be made to automatically align thesupport member40 at the optimal position. No such system existed in the prior art. However, the delivery system of the present invention provides such an alignment device, thereby, eliminating the need for physician guesswork as to the three-dimensional rotational position of the implanted stent graft1. This alignment device is explained in further detail below with respect toFIGS. 64 to 67.
• The delivery system of the present invention also has a very simple to use handle assembly. The handle assembly takes advantage of the fact that the inside diameter of the aorta is substantially larger that the inside diameter of the femoral arteries. The present invention, accordingly, uses a two-stage approach in which, after the device is inserted in through the femoral artery and tracks up into the abdominal area of the aorta (having a larger diameter (seeFIG. 19) than the femoral artery), a second stage is deployed (seeFIG. 20) allowing a small amount of expansion of the stent graft while still constrained in a sheath; but this sheath, made of fabric/woven polymer or similar flexible material, is very flexible. Such a configuration gives the delivery system greater flexibility for tracking, reduces deployment forces because of the larger sheath diameter, and easily overcome kinks because the sheath is made of fabric.
• To describe the delivery system of the present invention, the method for operating thedelivery assembly600 will be described first in association withFIGS. 10,11, and12. Thereafter, the individual components will be described to allow a better understanding of how each step in the process is effected for delivering the stent graft1 to any portion of the aorta700 (seeFIGS. 19 to 24), in particular, thecurved portion710 of the aorta.
• Initially, thedistal end14 of the stent graft1 is compressed and placed into a hollow, cup-shaped, or tubular-shaped graft holding device, in particular, the distal sleeve644 (see, e.g.,FIG. 25). At this point, it is noted that the convention for indicating direction with respect to delivery systems is opposite that of the convention for indicating direction with respect to stent grafts. Therefore, the proximal direction of the delivery system is that portion closest to the user/physician employing the system and the distal direction corresponds to the portion farthest away from the user/physician, i.e., towards thedistal-most nose cone632.
• Thedistal sleeve644 is fixedly connected to the distal end of thegraft push lumen642, which lumen642 provides an end face for thedistal end14 of the stent graft1. Alternatively, thedistal sleeve644 can be removed entirely. In such a configuration, as shown inFIG. 12, for example, the proximal taper of theinner sheath652 can provide the measures for longitudinally holding the compressed distal end of the graft1. If thesleeve644 is removed, it is important to prevent thedistal end14 of the stent graft1 from entering the space between the interior surface of thehollow sheath lumen654 and the exterior surface of thegraft push lumen642 slidably disposed in thesheath lumen654. Selecting a radial thickness of the space to be less than the diameter of the wire making up thestent20,30 (in particular, no greater than half a diameter thereof) insures reliable movement of thedistal end14 of the stent graft1. In another alternative configuration shown inFIG. 68, thedistal sleeve644 can be a disk-shapedbuttress644 present at the distal end of thegraft push lumen642. An example configuration can provide the buttress644 with a hollowproximal insertion peg6442, a hollowdistal stiffening tube6444, and an intermediate buttresswall6446. Thebuttress644 is concentric to the center axis of thedelivery system600 and allows theco-axial guidewire lumen620 andapex release lumen640 to pass therethrough. Thepeg6442 allows for easy connection to the graft push lumen643. The stiffening tube64 creates a transition in stiffness from thegraft push lumen642 to theapex release lumen620 andguidewire lumen640 and provides support to thelumen620,640 located therein. Such a transition in stiffness reduces any possibility of kinking at the distal end of thegraft push lumen642 and aids in transferring force from thegraft push lumen642 to the lumen therein620,640 when all are in a curved orientation. The buttresswall6446 provides a flat surface that will contact the distal-end-facing side of the stent graft1 and can be used to push the stent graft distally when thegraft push lumen642 is moved distally. The alternative configuration of thebuttress644 insures that the stent graft1 does not become impinged within thegraft push lumen642 and the lumen therein620,640 when these components are moved relative to each other.
• As set forth in more detail below, each apex32 of thebare stent30 is, then, loaded into theapex capture device634 so that the stent graft1 is held at both its proximal and distal ends. The loadeddistal end14, along with thedistal sleeve644 and thegraft push lumen642, are, in turn, loaded into theinner sheath652, thus, further compressing the entirety of the stent graft1. The capturedbare stent30, along with the nose cone assembly630 (including the apex capture device634), is loaded until the proximal end of thenose cone632 rests on the distal end of theinner sheath652. The entirenose cone assembly630 andsheath assembly650 is, then, loaded proximally into the rigidouter catheter660, further compressing the stent graft1 (resting inside the inner sheath652) to its fully compressed position for later insertion into a patient. SeeFIG. 63.
• The stent graft1 is, therefore, held both at its proximal and distal ends and, thereby, is both pushed and pulled when moving from a first position (shown inFIG. 19 and described below) to a second position (shown inFIG. 21 and described below). Specifically, pushing is accomplished by the non-illustrated interior end face of the hollow distal sleeve644 (or thetaper653 of the inner sheath652) and pulling is accomplished by the hold that theapex capture device634 has on theapices32 of thebare stent30.
• Theassembly600 according to the present invention tracks along aguidewire610 already inserted in the patient and extending through the aorta and up to, but not into, the left ventricle of theheart720. Therefore, aguidewire610 is inserted through theguidewire lumen620 starting from thenose cone assembly630, through thesheath assembly650, through the handle assembly670, and through theapex release assembly690. Theguidewire610 extends out the proximal-most end of theassembly600. Theguidewire lumen620 is coaxial with thenose cone assembly630, thesheath assembly650, the handle assembly670, and theapex release assembly690 and is the innermost lumen of theassembly600 immediately surrounding theguidewire610.
• Before using thedelivery system assembly600, all air must be purged from inside theassembly600. Therefore, a liquid, such as sterile U.S.P. saline, is injected through a non-illustrated tapered luer fitting to flush the guidewire lumen at a non-illustrated purge port located near a proximal end of the guidewire lumen. Second, saline is also injected through the luer fitting612 of the lateral purge-port (seeFIG. 11), which liquid fills the entire internal co-axial space of thedelivery system assembly600. It may be necessary to manipulate the system to facilitate movement of the air to be purged to the highest point of the system.
• After purging all air, the system can be threaded onto the guidewire and inserted into the patient. Because theouter catheter660 has a predetermined length, the fixed front handle672 can be disposed relatively close to the entry port of the femoral artery. It is noted, however, that the length of theouter catheter660 is sized such that it will not have the fixedproximal handle672 directly contact the entry port of the femoral artery in a patient who has the longest distance between the entry port and the thoracic/abdominal junction742,732 of the aorta expected in a patient (this distance is predetermined). Thus, thedelivery assembly600 of the present invention can be used with typical anatomy of the patient. Of course, theassembly600 can be sized to any usable length.
• Thenose cone assembly630 is inserted into a patient's femoral artery and follows theguidewire610 until thenose cone632 reaches the first position at least to a level of the celiac axis and possibly further but not into the intended stent graft deployment site, which would prevent deployment of at least the downstream end of the stent graft. The first position is shown inFIG. 19. Thenose cone assembly630 is radiopaque, whether wholly or partially, to enable the physician to determine fluoroscopically, for example, that thenose cone assembly630 is in the first position. For example, thenose cone632 can have aradiopaque marker631 anywhere thereon or thenose cone632 can be entirely radiopaque.
• FIGS. 19 to 24 illustrate thecatheter660 extending approximately up to the renal arteries. However, thecatheter660 of the present invention is configured to travel up to at least the celiac axis (not shown inFIGS. 19 to 24). As used herein, the celiac axis is to be defined according to common medical terms. In a simplistic definition, the celiac axis is a plane that intersects and is parallel to a central axis of a patient's celiac at the intersection of the celiac and the aorta and, therefore, this plane is approximately orthogonal to the longitudinal axis of the abdominal/thoracic aorta at the point where the celiac intersects the aorta. Therefore, with respect to extension of thecatheter660 into the aorta, it is extended into the aorta up to but not past the intended downstream end of the implant. After arriving at this distal-most position, the distal end of thecatheter660 remains substantially steady along the longitudinal axis of the aorta until after the stent graft1 is implanted (seeFIG. 24) and the entire delivery system is to be removed from the patient. While the delivery system of the present invention can be retracted in the orientation shown inFIG. 24 except for one difference (thebare stent32 is open and theapex release device634 is released from compressing the bare stent32), the preferred embodiment for removal of thecatheter660 from the aorta after implantation of the stent graft1 occurs with reference to the condition shown In FIG.19—where all of theinterior lumens620,640,642,654 are retracted inside thecatheter660 and thenose cone631 is in contact with the distal end of thecatheter660.
• After thenose cone assembly630 is in the first position shown inFIG. 19, the locking knob orring676 is placed from its neutral position into its advancement position. As will be described below, placing the lockingknob676 into its advancement position A allows both thenose cone assembly630 and theinternal sheath assembly650 to move as one when theproximal handle678 is moved in either the proximal or distal directions because the lockingknob676 radially locks thegraft push lumen642 to the lumens of the apex release assembly690 (including theguidewire lumen620 and an apex release lumen640). The lockingknob676 is fixedly connected to asheath lumen654.
• Before describing how various embodiments of the handle assembly670 function, a summary of the multi-lumen connectivity relationships, throughout the neutral, advancement, and deployment positions, is described.
• When the locking ring is in the neutral position, thepusher clasp spring298 shown inFIG. 48 and the distalclasp body spring606 shown inFIG. 52 are both disengaged. This allows free movement of thegraft push lumen642 with theguidewire lumen620 and theapex release lumen640 within thehandle body674.
• When the lockingknob676 is moved into the advancement position, thepusher clasp spring298 shown inFIG. 48 is engaged and the distalclasp body spring606 shown inFIG. 52 is disengaged. The sheath lumen654 (fixedly attached to the inner sheath652) is, thereby, locked to the graft push lumen642 (fixedly attached to the distal sleeve644) so that, when theproximal handle678 is moved toward thedistal handle672, both thesheath lumen654 and thegraft push lumen642 move as one. At this point, thegraft push lumen642 is also locked to both theguidewire lumen620 and the apex release lumen640 (which are locked to one another through theapex release assembly690 as set forth in more detail below). Accordingly, as theproximal handle678 is moved to the second position, shown with dashed lines inFIG. 11, thesheath assembly650 and thenose cone assembly630 progress distally out of theouter catheter660 as shown inFIGS. 20 and 21 and with dashed lines inFIG. 11.
• At this point, thesheath lumen654 needs to be withdrawn from the stent graft1 to, thereby, expose the stent graft1 from itsproximal end12 to itsdistal end14 and, ultimately, entirely off of itsdistal end14. Therefore, movement of the lockingknob676 into the deployment position D will engage the distalclasp body spring606 shown inFIG. 52 and disengage thepusher clasp spring298 shown inFIG. 48. Accordingly, thegraft push lumen642 along with theguidewire lumen620 and theapex release lumen640 are locked to thehandle body674 so as not to move with respect to thehandle body674. Thesheath lumen654 is unlocked from thegraft push lumen642. Movement of thedistal handle678 back to the third position (proximally), therefore, pulls thesheath lumen654 proximally, thus, proximally withdrawing theinner sheath652 from the stent graft1.
• At this point, thedelivery assembly600 only holds thebare stent30 of the stent graft1. Therefore, final release of the stent graft1 occurs by releasing thebare stent30 from thenose cone assembly630, which is accomplished using theapex release assembly690 as set forth below.
• In order to explain how the locking and releasing of the lumen occur as set forth above, reference is made toFIGS. 33 to 62.
• FIG. 33 is a cross-sectional view of theproximal handle678 and the lockingknob676. Apusher clasp rotator292 is disposed between aclasp sleeve614 and thegraft push lumen642. A specific embodiment of thepusher clasp rotator292 is illustrated inFIGS. 34 through 39. Also disposed between theclasp rotator292 and thegraft push lumen642 is arotator body294, which is directly adjacent thegraft push lumen642. A specific embodiment of therotator body294 is illustrated inFIGS. 40 through 43. Disposed between therotator body294 and thesheath lumen654 is apusher clasp body296, which is fixedly connected to therotator body294 and to the lockingknob676. A specific embodiment of thepusher clasp body296 is illustrated inFIGS. 44 through 46. Apusher clasp spring298 operatively connects thepusher clasp rotator292 to the rotator body294 (and, thereby, the pusher clasp body296).
• An exploded view of these components is presented inFIG. 48, where an O-ring293 is disposed between therotator body294 and thepusher clasp body296. As shown in the plan view ofFIG. 47, acrimp ring295 connects thesheath lumen654 to thedistal projection297 of thepusher clasp body296. A hollow handle body674 (seeFIGS. 10,11, and33), on which theproximal handle678 and the lockingknob676 are slidably mounted, holds thepusher clasp rotator292, therotator body294, thepusher clasp body296, and thepusher clasp spring298 therein. This entire assembly is rotationally mounted to thedistal handle672 for rotating the stent graft1 into position (seeFIGS. 23 and 24 and the explanations thereof below). A specific embodiment of thehandle body674 is illustrated inFIG. 49.
• A setscrew679 extends from theproximal handle678 to contact a longitudinally helixed groove in the pusher clasp rotator292 (shown inFIGS. 36 and 38). Thus, when moving theproximal handle678 proximally or distally, thepusher clasp rotator292 rotates clockwise or counter-clockwise.
• An alternative embodiment of the lockingknob676 is shown inFIG. 50 et seq. in which, instead of applying a longitudinal movement to rotate thepusher clasp spring298 through the cam/follower feature of theproximal handle678 andpusher clasp rotator292, arotating locking knob582 is located at the proximal end of thehandle body674. Theknob582 has three positions that are clearly shown inFIG. 51: a neutral position N, an advancement position A, and a deployment position D. The functions of these positions N, A, D correspond to the positions N, A, D of the lockingknob676 and theproximal handle678 as set forth above.
• In the alternative embodiment, a setscrew or pin584 is threaded into theclasp sleeve614 through aslot675 in thehandle body674 and through aslot583 in theknob582 to engage the lockingknob582. The depth of thepin584 in theclasp sleeve614 is small because of the relatively small thickness of theclasp sleeve614. To provide additional support to thepin584 and prevent it from coming out of theclasp sleeve614, an outer ring6144 is disposed on the exterior surface of the proximal end of theclasp sleeve614. Because of the x-axis orientation of theslot583 in theknob582 and the y-axis orientation of theslot675 in thehandle body674, when theknob582 is slid over the end of thehandle body674 and thesetscrew584 is screwed into theclasp sleeve614, theknob582 is connected fixedly to thehandle body674. When the lockingknob582 is, thereafter, rotated between the neutral N, advancement A, and deployment D positions, theclasp sleeve614 rotates to actuate the spring lock (seeFIGS. 48 and 52).
• Asetscrew586, shown inFIG. 53, engages agroove605 in theproximal clasp assembly604 to connect theproximal clasp assembly604 to theclasp sleeve614 but allows theclasp sleeve614 to rotate around theclasp body602. Theclasp sleeve614 is shown inFIGS. 50 and 53 and, in particular, inFIGS. 59 to 62. Theproximal clasp assembly604 ofFIG. 53 is more clearly shown in the exploded view ofFIG. 52. Theproximal clasp assembly604 is made of the components including a distalclasp body spring606, a lockingwasher608, a fastener603 (in particular, a screw fitting into internal threads of the proximal clasp body602), and aproximal clasp body602. Theproximal clasp body602 is shown, in particular, inFIGS. 54 through 58. Theproximal clasp assembly604 is connected fixedly to thehandle body674, preferably, with ascrew585 shown inFIG. 50 and hidden from view inFIG. 51 underknob582.
• Thehandle body674 has aposition pin592 for engaging in position openings at the distal end of the lockingknob582. Theposition pin592 can be a setscrew that only engages thehandle body674. When the lockingknob582 is pulled slightly proximally, therefore, the knob can be rotated clockwise or counter-clockwise to place thepin592 into the position openings corresponding to the advancement A, neutral N, and deployment D positions.
• As shown inFIG. 18, to begin deployment of the stent graft1, the user/physician grasps both thedistal handle672 and theproximal handle678 and slides theproximal handle678 towards thedistal handle672 in the direction indicated by arrow A. This movement, as shown inFIGS. 19 to 21, causes the flexibleinner sheath652, holding the compressed stent graft1 therein, to emerge progressively from inside theouter catheter660. Such a process allows the stent graft1, while constrained by theinner sheath652, to expand to a larger diameter shown inFIG. 12, this diameter being substantially larger than the inner diameter of theouter catheter660 but smaller than the inner diameter of the vessel in which it is to be inserted. Preferably, theouter catheter660 is made of a polymer (co-extrusions or teflons) and theinner sheath652 is made of a material, such as a fabric/woven polymer or other similar material. Therefore, theinner sheath652 is substantially more flexible than theouter catheter660.
• It is noted, at this point, that theinner sheath652 contains ataper653 at its proximal end, distal to the sheath's652 connection to the sheath lumen654 (at which connection theinner sheath652 has a similar diameter to thedistal sleeve644 and works in conjunction with thedistal sleeve644 to capture thedistal end14 of the stent graft1. Thetaper653 provides a transition that substantially prevents any kinking of theouter catheter660 when the stent graft1 is loaded into the delivery assembly600 (as in the position illustrated inFIGS. 10 and 11) and, also, when theouter catheter660 is navigating through the femoral and iliac vessels. One specific embodiment of thesheath lumen654 has a length between approximately 30 and approximately 40 inches, in particular, 36 inches, an outer diameter of between approximately 0.20 and approximately 0.25 inches, in particular 0.238 inches, and an inner diameter between approximately 0.18 and approximately 0.22 inches, in particular, 0.206 inches.
• When theproximal handle678 is moved towards its distal position, shown by the dashed lines inFIG. 11, thenose cone assembly630 and thesheath assembly650 move towards a second position where thesheath assembly650 is entirely out of theouter catheter660 as shown inFIGS. 20 and 21. As can be seen most particularly inFIGS. 20 and 21, as thenose cone assembly630 and thesheath assembly650 are emerging out of theouter catheter660, they are traversing thecurved portion710 of the descending aorta. The tracking is accomplished visually by viewing radiopaque markers on various portions of the delivery system and/or the stent graft1 with fluoroscopic measures. Such markers will be described in further detail below. The delivery system can be made visible, for example, by thenose cone630 being radiopaque or containing radiopaque materials.
• It is noted that if the harderouter catheter660 was to have been moved through thecurved portion710 of theaorta700, there is a great risk of puncturing theaorta700, and, particularly, adiseased portion744 of the proximal descendingaorta710 because theouter catheter660 is not as flexible as theinner sheath652. But, because theinner sheath652 is so flexible, thenose cone assembly630 and thesheath assembly650 can be extended easily into thecurved portion710 of theaorta700 with much less force on the handle than previously needed with prior art systems while, at the same time, imparting harmless forces to the intraluminal surface of thecurved aorta710 due to the flexibility of theinner sheath652.
• At the second position shown inFIG. 21, the user/physician, using fluoroscopic tracking of radiopaque markers (e.g., marker631) on any portion of the nose cone or on the stent graft1 and/orsheath assemblies630,650, for example, makes sure that the proximal end112 of the stent graft1 is in the correct longitudinal position proximal to thediseased portion744 of theaorta700. Because the entire insertedassembly630,650 in theaorta700 is still rotationally connected to the portion of the handle assembly670 except for the distal handle672 (distal handle672 is connected with theouter sheath660 and rotates independently of the remainder of the handle assembly670), the physician can rotate the entire insertedassembly630,650 clockwise or counterclockwise (indicated inFIG. 20 by arrow B) merely by rotating theproximal handle678 in the desired direction. Such a feature is extremely advantageous because the non-rotation of theouter catheter660 while theinner sheath652 is rotating eliminates stress on the femoral and iliac arteries when the rotation of theinner sheath652 is needed and performed.
• Accordingly, the stent graft1 can be pre-aligned by the physician to place the stent graft1 in the optimal circumferential position.FIG. 23 illustrates thelongitudinal support member40 not in the correct superior position andFIG. 24 illustrates thelongitudinal support member40 in the correct superior position. The optimal superior surface position is, preferably, near the longest superior longitudinal line along the circumference of the curved portion of the aorta as shown inFIGS. 23 and 24. As set forth above, when thelongitudinal support member40 extends along the superior longitudinal line of the curved aorta, thelongitudinal support member40 substantially eliminates any possibility of forming a kink in the inferior radial curve of the stent graft1 during use and also allows transmission of longitudinal forces exerted along the inside lumen of the stent graft1 to the entire longitudinal extent of the stent graft1, thereby allowing the entire outer surface of the stent graft1 to resist longitudinal migration. Because of the predefined curvature of thesupport member40, thesupport member40 cannot align exactly and entirely along the superior longitudinal line of the curved aorta. Accordingly, an optimal superior surface position of thesupport member40 places as much of the central portion of the support member40 (between the two ends47 thereof) as possible close to the superior longitudinal line of the curved aorta. A particularly desirable implantation position has the superior longitudinal line of the curved aorta intersecting the proximal half of thesupport member40—the proximal half being defined as that portion of thesupport member40 located between the centerline45 and the proximalsupport member loop47. However, for adequate implantation purposes, thecenterline45 of thesupport member40 can be as much as seventy circumferential degrees away from either side of the superior longitudinal line of the curved aorta. Adequate implantation can mean that the stent graft1 is at least approximately aligned. When implantation occurs with the stent graft1 being less than seventy degrees, for example, less than forty degrees, away from either side of the superior longitudinal line of the curved aorta, then it is substantially aligned.
• In prior art stent grafts and stent graft delivery systems, the stent graft is, typically, provided with symmetrically-shaped radiopaque markers along one longitudinal line and at least one other symmetrically-shaped radiopaque marker disposed along another longitudinal line on the opposite side (one-hundred eighty degrees (180°)) of the stent graft. Thus, using two-dimensional fluoroscopic techniques, the only way to determine if the stent graft is in the correct rotational position is by having the user/physician rotate the stent graft in both directions until it is determined that the first longitudinal line is superior and the other longitudinal line is anterior. Such a procedure requires more work by the physician and is, therefore, undesirable.
• According to an exemplary embodiment of the invention illustrated inFIGS. 27 and 28, uniqueradiopaque markers232,234 are positioned on the stent graft1 to assist the user/physician in correctly positioning thelongitudinal support member40 in the correct aortic superior surface position with only one directional rotation, which corresponds to the minimal rotation needed to place the stent graft1 in the rotationally correct position.
• Specifically, the stent graft1 is provided with a pair of symmetrically shaped but diametricallyopposed markers232,234 indicating to the user/physician which direction the stent graft1 needs to be rotated to align thelongitudinal support member40 to the superior longitudinal line of the curved aorta (with respect to anatomical position). Preferably, themarkers232,234 are placed at theproximate end12 of thegraft sleeve10 on opposite sides (one-hundred eighty degrees (180°)) of thegraft sleeve10.
• The angular position of themarkers232,234 on thegraft sleeve10 is determined by the position of thelongitudinal support member40. In an exemplary embodiment, thesupport member40 is between the twomarkers232,234. To explain such a position, if themarker232 is at a 0 degree position on thegraft sleeve10 and themarker234 is at a one-hundred eighty degree) (180° position, then thecenterline45 of thesupport member40 is at a ninety degree position. However, an alternative position of the markers can place themarker234 ninety degrees away from the first degree41 (seeFIG. 1). Such a positioning is dependent somewhat upon the way in which the implantation is to be viewed by the user/physician and can be varied based on other factors. Thus, the position can be rotated in any beneficial way.
• Exemplary ancillary equipment in endovascular placement of the stent graft1 is a fluoroscope with a high-resolution image intensifier mounted on a freely angled C-arm. The C-arm can be portable, ceiling, or pedestal mounted. It is important that the C-arm have a complete range of motion to achieve AP to lateral projections without moving the patient or contaminating the sterile field. Capabilities of the C-arm should include: Digital Subtraction Angiography, High-resolution Angiography, and Roadmapping.
• For introduction of the delivery system into the groin access arteries, the patient is, first, placed in a sterile field in a supine position. To determine the exact target area for placement of the stent graft1, the C-arm is rotated to project the patient image into a left anterior oblique projection, which opens the radial curve of the thoracic aortic arch for optimal visualization without superimposition of structures. The degree of patient rotation will vary, but is usually 40 to 50 degrees. At this point, the C-arm is placed over the patient with the central ray of the fluoroscopic beam exactly perpendicular to the target area. Such placement allows for themarkers232,234 to be positioned for correct placement of the stent graft1. Failure to have the central ray of the fluoroscopic beam perpendicular to the target area can result in parallax, leading to visual distortion to the patient anatomy due to the divergence of the fluoroscopic x-ray beam, with a resultant misplacement of the stent graft1. An angiogram is performed and the proposed stent graft landing zones are marked on the visual monitor. Once marked, neither the patient, the patient table, nor the fluoroscopic C-arm can be moved, otherwise, the reference markers become invalid. The stent graft1 is, then, placed at the marked landing zones.
• In an exemplary embodiment, themarkers232,234 are hemispherical, in other words, they have the approximate shape of a “D”. This shape is chosen because it provides special, easy-to-read indicators that instantly direct the user/physician to the correct placement position for thelongitudinal support member40.FIG. 27, for example, illustrates a plan view of themarkers232,234 when they are placed in the upper-most superior longitudinal line of the curved aorta. The correct position is indicated clearly because the two hemispheres have the flat diameters aligned on top of or immediately adjacent to one another such that a substantially complete circle is formed by the two hemispherically rounded portions of themarkers232,234. This position is also indicated in the perspective view ofFIG. 28.
• Each ofFIGS. 27 and 28 have been provided with examples where themarkers232,234 are not aligned and, therefore, the stent graft1 is not in the correct insertion position. For example, inFIG. 27, twomarkers232′,234′ indicate a misaligned counter-clockwise-rotated stent graft1 when viewed from theplane236 at the right end of the stent graft1 ofFIG. 23 looking toward the left end thereof and down the axis11. Thus, to align themarkers232′,234′ in the most efficient way possible (the shortest rotation), the user/physician sees that the distance between the two flat diameters is closer than the distance between the highest points of the hemispherical curves. Therefore, it is known that the two flat diameters must be joined together by rotating the stent graft1 clockwise.
• FIG. 28 has also been provided with twomarkers232″,234″ indicating a misaligned clockwise-rotated stent graft1 when viewed from theplane236 at the right end of the stent graft1 ofFIG. 27 looking toward the left end thereof and down the axis11. Thus, to align themarkers232″,234″ in the most efficient way possible (the shortest rotation), the user/physician sees that the distance between the highest points of the hemispherical curves is smaller than the distance between the two flat diameters. Therefore, it is known that the two flat diameters must be joined together by rotating the stent graft1 in the direction that the highest points of the hemispherical curves point; in other words, the stent graft1 must be rotated counter-clockwise.
• A significant advantage provided by the diametrically opposedsymmetric markers232,234 is that they can be used for migration diagnosis throughout the remaining life of a patient after the stent graft1 has been placed inside the patient's body. If fluoroscopic or radiographic techniques are used any time after the stent graft1 is inserted in the patient's body, and if the stent graft1 is viewed from the same angle as it was viewed when placed therein, then the markers'232,234 relative positions observed should give the examining individual a very clear and instantaneous determination as to whether or not the stent graft1 has migrated in a rotational manner.
• The hemispherical shape of themarkers232,234 are only provided as an example shape. Themarkers232,234 can be any shape that allows a user/physician to distinguish alignment and direction of rotation for alignment. For example, themarkers232,234 can be triangular, in particular, an isosceles triangle having the single side be visibly longer or shorter than the two equal sides.
• As set forth above, alignment to the optimal implantation position is dependent upon the skill of the physician(s) performing the implantation. The present invention improves upon the embodiments having longitudinal and rotationalradiopaque markers232,234 and substantially eliminates the need for rotational markers. Specifically, it is noted that theguidewire610 travels through a curve through the aortic arch towards theheart720. It is, therefore, desirable to pre-shape the delivery system to match the aorta of the patient.
• Theguidewire lumen620 is formed from a metal, preferably, stainless steel. Thus, theguidewire lumen620 can be deformed plastically into any given shape. In contrast, theapex release lumen640 is formed from a polymer, which tends to retain its original shape and cannot plastically deform without an external force, e.g., the use of heat. Therefore, to effect the pre-shaping of thedelivery assembly600, theguidewire lumen620, as shown inFIG. 64, is pre-shaped with a curve at adistal-most area622 of thelumen620. The pre-shape can be determined, for example, using the fluoroscopic pre-operative techniques described above, in which theguidewire lumen620 can be customized to the individual patient's aortic shape. Alternatively, theguidewire lumen620 can be pre-shaped in a standard manner that is intended to fit an average patient. Another alternative is to provide a kit that can be used to pre-shape theguidewire lumen620 in a way that is somewhat tailored to the patient, for example, by providing a set ofdelivery systems600 or a set of differentguidewire lumens620 that have different radii of curvature.
• With thepre-curved guidewire lumen620, when thenose cone632 andinner sheath652 exit theouter catheter660 and begin to travel along thecurved guidewire610, the natural tendency of thepre-curved guidewire lumen620 will be to move in a way that will best align the two curves to one another (seeFIGS. 20 and 21). The primary factor preventing theguidewire lumen620 from rotating itself to cause such an alignment is the torque generated by rotating theguidewire lumen620 around theguidewire610. The friction between the aorta and the device also resists rotational motion. Thedelivery system600, however, is configured naturally to minimize such torque. As set forth above with respect toFIGS. 15 to 17, theguidewire lumen620 freely rotates within theapex release lumen640 and is only connected to theapex release lumen640 at the proximal-most area of bothlumen620,640. While theinner sheath652 advances through the aortic arch, the twolumen620,640 are rotationally connected only at theapex release assembly690. This means that rotation of theguidewire lumen620 about theguidewire610 and within theapex release lumen640 occurs along the entire length of theguidewire lumen620. Because themetallic guidewire lumen620 is relatively rotationally elastic along its length, rotation of the distal-most portion (near the nose cone assembly630) with respect to the proximal-most portion (near the apex release assembly690) requires very little force. In other words, the torque resisting rotation of the distal-most portion to conform to the curve of theguidewire610 is negligible. Specifically, the torque is so low that the force resisting the alignment of theguidewire lumen620 to theguidewire610 causes little, negligible, or no damage to the inside of the aorta, especially to a dissecting inner wall of a diseased aorta.
• Due to the configuration of thedelivery system600 of the present invention, when theguidewire lumen620 is extended from the outer catheter660 (along with theapex release lumen640, the stent graft1, theinner sheath652 as shown inFIGS. 20 and 21, for example), the pre-shape of theguidewire lumen620 causes automatic and natural rotation of the entire distal assembly—including the stent graft1—along its longitudinal axis. This means that the length and connectivity of theguidewire lumen620, and the material from of which theguidewire lumen620 is made, allow the entire distal assembly (1,620,630,640,650) to naturally rotate and align thepre-curved guidewire lumen620 with the curve of theguidewire610—this is true even if theguidewire lumen620 is inserted into the aorta entirely opposite the curve of the aorta (one-hundred eighty degrees (180°)). In all circumstances, thecurved guidewire lumen620 will cause rotation of the stent graft1 into an optimal implantation position, that is, aligning the desired portion of thesupport member40 within ±70 degrees of the superior longitudinal line of the curved aorta. Further, the torque forces acting against rotation of theguidewire lumen620 will not be too high to cause damage to the aorta while carrying out the rotation.
• The self-aligning feature of the invention begins with a strategic loading of the stent graft1 in theinner sleeve652. To describe the placement of the supportingmember40 of the stent graft1 relative to thecurve622 of theguidewire lumen620, an X-Y coordinate curve plane is defined and shown inFIG. 64. In particular, theguidewire lumen620 is curved and thatcurve622 defines thecurve plane624.
• To insure optimal implantation, when loading the stent graft1 into theinner sheath652, a desired point on the supportingmember40 between thecenterline45 of the stent graft1 and the proximalsupport member loop47 is aligned to intersect thecurve plane624. An exemplary, but not required, location of the desired point on the supportingmember40 is located forty-five (45) degrees around the circumference of the stent graft1 shown inFIG. 1 beginning from the first degree41 in line with the proximalsupport member loop47. When the stent graft1 is loaded in an exemplary orientation, it is ready for insertion into theinner sleeve652. During the loading process, the stent graft1 and theguidewire lumen620 are held constant rotationally. After such loading, theinner sleeve652 is retracted into theouter catheter660 and thedelivery system600 is ready for purging with saline and use with a patient.
• FIGS. 65 to 67 illustrate self-alignment of thedistal assembly620,630,640,650 after it is pushed out from the distal end of the outer catheter660 (seeFIGS. 20 and 21).FIG. 65 shows anaorta700 and the distal assembly after it has traversed theiliac arteries802 and enters the descendingthoracic portion804 of the aorta. Thenose cone assembly630 is positioned just before theaortic arch806 and the stent graft1 is contained within theinner sheath652. Areference line820 is placed on the stent graft1 at a longitudinal line of the stent graft1 that is intended to align with the superior longitudinal line808 (indicated with dashes) of theaortic arch806. InFIG. 65, thereference line820 also lies on thecurved plane624 defined by thepre-curved guidewire lumen620. As can be clearly seen fromFIG. 65, thereference line820 is positioned almost on or on the inferior longitudinal line of the curved aorta—thus, the stent graft1 is one-hundred eighty degrees (180°) out of alignment.FIG. 66 shows thenose cone assembly630 fully in theaortic arch806 and theinner sleeve652 at the entrance of theaortic arch806. With the self-aligning configuration of thepre-curved guidewire lumen620, movement of the distal assembly from the position shown inFIG. 65 to the position shown inFIG. 66 causes a rotation of thereference line820 almost ninety degrees (90°) clockwise (with respect to a view looking upward within the descending aorta) towards the superiorlongitudinal line808. InFIG. 67, thenose cone assembly630 has reached, approximately, the leftsubclavian artery810. Rotational movement of the distal assembly is, now, complete, with thereference line820 almost aligned with the superiorlongitudinal line808 of theaortic arch806. From the views ofFIGS. 65 to 67, also shown is the fact that thepre-curved guidewire lumen620 has not caused any portion of theinner sleeve652 to push against the inner surface of theaortic arch806 with force—force that might exacerbate an aortic dissection.
• It is noted that theguidewire lumen620 need not be rotationally fixedly connected to theapex release lumen640 when theapex release assembly690 is in the locked position shown inFIGS. 15 and 16. Instead, a non-illustrated, freely rotatable coupling can be interposed anywhere along the guidewire lumen620 (but, preferably, closer to the apex release assembly690). This coupling would have a proximal portion rotationally fixedly connected to the to theapex release lumen640 when theapex release assembly690 is in the locked position shown inFIGS. 15 and 16 and a freely-rotatable distal portion that is fixedly connected to all of theguidewire lumen620 disposed distal thereto. Thus, theguidewire lumen620 near thesheath assembly650 will always be freely rotatable and, thereby, allow easy and torque-free rotation of theguidewire lumen620 about theguidewire610.
• It is also noted that thepre-curved section622 of the guidewire lumen need not be made at the manufacturer. As shown inFIG. 69, a curving device can be provided with thedelivery system600 to allow the physician performing the implantation procedure to tailor-fit thecurve622 to the actual curve of the vessel in which the stent graft1 is to be implanted. Because different patients can have different aortic arch curves, a plurality of these curving devices can be provided with thedelivery system600, each of the curving devices having a different curved shape. Each device can also have two sides with each side having a different curved shape, thus, reducing the number of devices if a large number of curves are required. Further, the curving devices can all be rotationally connected on a common axle or spindle for each of transport, storage, and use.
• For tailoring the curve to the patient's curved vessel, the physician can, for example, fluoroscopically view the vessel (e.g., aortic arch) and determine therefrom the needed curve by, for example, holding up the curving device to the display. Any kind of curving device can be used to impart a bend to theguidewire lumen620 when theguidewire lumen620 is bent around the circumference.
• Because of the predefined curvature of thesupport member40, thesupport member40 cannot align exactly and entirely along the superior longitudinal line of the curved aorta. Accordingly, an optimal superior surface position of thesupport member40 places as much of the central portion of the support member40 (between the two ends47 thereof) as possible close to the superiorlongitudinal line808 of the curved aorta. A particularly desirable implantation position has the superiorlongitudinal line808 of the curved aorta intersecting the proximal half of thesupport member40—the proximal half being defined as that portion of thesupport member40 located between the centerline45 and the proximalsupport member loop47. However, for adequate implantation purposes, thecenterline45 of thesupport member40 can be as much as seventy circumferential degrees away from either side of the superior longitudinal line of the curved aorta.
• When the stent graft1 is in place both longitudinally and circumferentially (FIG. 21), the stent graft1 is ready to be removed from theinner sheath652 and implanted in thevessel700. Because relative movement of the stent graft1 with respect to the vessel is no longer desired, theinner sheath652 needs to be retracted while the stent graft1 remains in place, i.e., no longitudinal or circumferential movement. Such immovability of the stent graft1 is insured by, first, theapex capture device634 of thenose cone assembly630 holding the front of the stent graft1 by its bare stent30 (seeFIGS. 13,22, and23) and, second, by unlocking the lockingknob676/placing the locking ring/knob in the D position—which allows thesheath lumen654 to move independently from theguidewire lumen620,apex release lumen640, andgraft push lumen642. Theapex capture device634, as shown inFIGS. 13,14,30 and311 (and as will be described in more detail below), is holding each individualdistal apex32 of thebare stent30 in a secure manner—both rotationally and longitudinally.
• Thenose cone assembly630, along with theapex capture device634, is securely attached to the guidewire lumen620 (and theapex release lumen640 at least until apex release occurs). Theinner sheath652 is securely attached to asheath lumen654, which is coaxially disposed around theguidewire lumen620 and fixedly attached to theproximal handle678. The stent graft1 is also supported at its distal end by thegraft push lumen642 and thedistal sleeve644 or, thetaper653 of theinner sheath652. (The entire coaxial relationship of thevarious lumens610,620,640,642,654, and660 is illustrated for exemplary purposes only inFIG. 25, and a portion of which can also be seen in the exploded view of the handle assembly inFIG. 50) Therefore, when theproximal handle678 is moved proximally with the lockingknob676 in the deployment position D, thesheath lumen654 moves proximally as shown inFIGS. 13,22, and23, taking thesheath652 proximally along with it while theguidewire lumen620, theapex release lumen640, thegraft push lumen642, and thedistal sleeve644 remain substantially motionless and, therefore, the stent graft1 remains both rotationally and longitudinally steady.
• The stent graft1 is, now, ready to be finally affixed to theaorta700. To perform the implantation, thebare stent30 must be released from theapex capture device634. As will be described in more detail below, theapex capture device634 shown inFIGS. 13,14, and29 to32, holds theproximal apices32 of thebare stent30 between thedistal apex head636 and the proximalapex body638. Thedistal apex head636 is fixedly connected to theguidewire lumen620. The proximalapex body638, however, is fixedly connected to theapex release lumen640, which is coaxial with both theguidewire lumen620 and thesheath lumen654 and disposed therebetween, as illustrated diagrammatically inFIG. 25. (As will be described in more detail below, thegraft push lumen642 is also fixedly connected to theapex release lumen640.) Therefore, relative movement of theapex release lumen640 and theguidewire lumen620 separates thedistal apex head636 and a proximalapex body638 from one another.
• To cause such relative movement, theapex release assembly690 has, in an exemplary embodiment, three parts, adistal release part692, aproximal release part694, and an intermediate part696 (which is shown in the form of a clip inFIGS. 16 and 26). To insure that thedistal apex head636 and the proximalapex body638 always remain fixed with respect to one another until thebare stent30 is ready to be released, theproximal release part694 is formed with adistal surface695, thedistal release part692 is formed with aproximal surface693, and theintermediate part696 has proximal and distal surfaces corresponding to thesurfaces695,693 such that, when theintermediate part696 is inserted removably between thedistal surface695 and theproximal surface693, theintermediate part696 fastens thedistal release part692 and theproximal release part694 with respect to one another in a form-locking connection. A form-locking connection is one that connects two elements together due to the shape of the elements themselves, as opposed to a force-locking connection, which locks the elements together by force external to the elements. Specifically, as shown inFIG. 26, theclip696 surrounds adistal plunger699 of theproximal release part694 that is inserted slidably within a hollow698 of thedistal release part692. Theplunger699 of theproximal release part694 can slide within the hollow698, but astop697 inside the hollow698 prevents thedistal plunger699 from withdrawing from the hollow698 more than the longitudinal span of theclip696.
• To allow relative movement between thedistal apex head636 and the proximalapex body638, theintermediate part696 is removed easily with one hand and, as shown from the position inFIG. 16 to the position inFIG. 17, thedistal release part692 and theproximal release part694 are moved axially towards one another (preferably, the former is moved towards the latter). Such movement separates thedistal apex head636 and the proximalapex body638 as shown inFIG. 14. Accordingly, thedistal apices32 of thebare stent30 are free to expand to their natural position in which thebare stent30 is released against thevessel700.
• Of course, theapex release assembly690 can be formed with any kind of connector that moves theapex release lumen640 and theguidewire lumen620 relative to one another. In an exemplary alternative embodiment, for example, theintermediate part696 can be a selectable lever that is fixedly connected to either one of thedistal release part692 or theproximal release part694 and has a length equal to the width of theclip696 shown inFIG. 26. Thus, when engaged by pivoting the lever between thedistal release part692 and theproximal release part694, for example, theparts692,694 cannot move with respect to one another and, when disengaged by pivoting the lever out from between theparts692,694, thedistal release part692 and theproximal release part694 are free to move towards one another.
• Theapex capture device634 is unique to the present invention in that it incorporates features that allow the longitudinal forces subjected on the stent graft1 to be fully supported, through thebare stent30, by both theguidewire lumen620 andapex release lumen640. Support occurs by providing thedistal apex head636 with adistal surface639—which surface639 supports theproximal apices32 of the bare stent30 (shown in the enlarged perspective view of thedistal apex head636 inFIG. 29). When captured, eachproximal apex32 of thebare stent30 separately rests on adistal surface639, as more clearly shown inFIGS. 30 and 31. The proximal spokes of thedistal apex head636 slide within the fingers of the proximalapex body638 as these parts moves towards one another. A slight space, therefore, exists between the fingers and the outer circumferential surfaces of the spokes. To insure that thebare stent30 does not enter this space (which would prevent a proper release of thebare stent30 from theapex capture device634, a radial thickness of the space must be less than the diameter of the wire making up thebare stent30. Preferably, the space is no greater than half a diameter of the wire.
• Having thedistal surface639 be the load-bearing surface of theproximal apices32 ensures expansion of each and every one of thedistal apices32 from theapex release assembly690. Theproximal surface641 of the distal apex head636 (seeFIG. 30) meets with the interior surfaces of the proximalapex body638 to help carry the apex load because the apices of thebare stent30 are captured therebetween when theapex capture device634 is closed. Complete capture of thebare stent30, therefore, fully transmits any longitudinal forces acting on thebare stent30 to both theguidewire lumen620 andapex release lumen640, making the assembly much stronger. Such capture can be clearly seen in the cut-away view of the proximalapex body638 inFIG. 31. For release of theapices32 of thebare stent30, the proximalapex body638 moves leftward with respect toFIGS. 30 to 33 (compareFIGS. 30 and 31 withFIG. 32). Because friction exists between theapices32 and the “teeth” of the proximalapex body638 when theapices32 are captured, theapices32 will also try to move to the left along with the proximalapex body638 and, if allowed to do so, possibly would never clear the “teeth” to allow each apex32 to expand. However, as the proximalapex body638 disengages (moves in the direction of arrow C inFIG. 31), direct contact with thedistal surface639 entirely prevents theapices32 from sliding in the direction of arrow C along with the proximalapex body638 to ensure automatic release of every capturedapex32 of thebare stent30. Because the proximalapex body638 continues to move in the direction of arrow C, eventually the “teeth” will clear their respective capture of theapices32 and thebare stent30 will expand entirely. The release position of thedistal apex head636 and the proximalapex body638 is shown inFIGS. 14 and 32, and corresponds to the position of theapex release assembly690 inFIG. 17. As can be seen, tapers on the distal outer surfaces of the proximalapex body638 further assist in the prevention of catching theproximal apices32 of thebare stent30 on any part of theapex capture device634. In this configuration, thedistal surfaces639 bear all the load upon thebare stent30 and the fingers of the proximalapex body638.
• Simply put, theapex capture device634 provides support for load placed on the stent graft1 during advancement A of theinner sheath652 and during withdrawal of the inner sheath652 (i.e., during deployment D). Such a configuration benefits the apposition of thebare stent30 by releasing thebare stent30 after theentire graft sleeve10 has been deployed, thus reducing the potential for vessel perforation at the point of initial deployment.
• When the stent graft1 is entirely free from theinner sheath652 as shown inFIG. 24, theproximal handle678 is, then, substantially at or near the third position (deployment position) shown inFIG. 10.
• The stent graft1 is, now, securely placed within thevessel700 and theentire portion630,650,660 of theassembly600 may be removed from the patient.
• FIGS. 70 and 71 illustrate alternative configurations of the stent graft1 ofFIG. 1. Thestent graft1000 ofFIG. 70 is similar to the stent graft1 ofFIG. 1. Thestent graft1000 has agraft1010 and a number ofstents1020. Thestents1020 are attached either to the exterior or interior surfaces of thegraft sleeve1010. Preferably, thestents1020 are sewn to thegraft1010. Thestent graft1000 shown inFIG. 70 has been discussed above with respect toFIG. 1, for example, and, therefore, the discussion relevant to features already discussed will not be repeated for the sake of brevity.
• FIG. 70 shows an exemplary embodiment of the curved ends1047 of the connectingrod1040. In particular, therod1040 forms a loop (whether, polygonal, ovular, or circular) and has anend portion1048 that continues back parallel and next to therod1040 for a short distance. Thisend portion1048, along with the adjacent portion of therod1040 allows, for example, connective stitching to cover two lengths of therod1040 and better secures theend portion1048 to thegraft sleeve1010. In such configuration, there is limited or even no chance of a sharp end of therod1040 to be exposed to harm thegraft sleeve1010 or the vessel wall in which thestent graft1000 is placed.
• An alternative embodiment of thestent graft1000 is shown asstent graft1100 inFIG. 71. Thisstent graft1100 contains agraft sleeve1110 that completely covers thebare stent30 shown inFIGS. 1 and 70 and is hereinafter referred to with respect toFIGS. 71 to 78 as aclasping stent1130. As shown particularly well inFIGS. 72 and 74, theclasping stent1130 is entirely covered by thegraft1110 but is not attached to the material of thegraft1110 along its entirety.
• At least some of theproximal apices1132, preferably, at least three or four, are left unconnected to permit a releasable connection with the fingers of the proximalapex body638 when the fingers are extended through theapex openings1134. Of course, in certain applications, it may be beneficial to only leave one apex1132 unconnected. The unconnected portion of each theapices1132 has a minimal longitudinal length of about 10 percent of the longitudinal length of the stent and a maximum longitudinal length of up to approximately 90 percent of the length of the stent. Preferably, the longitudinal length of the unconnected portion is between approximately 30 to 40 percent as shown inFIGS. 72 and 74, which show theclasping stent1130 sewn to the interior of thegraft1110. For ease of comparison,FIG. 73 illustrating the proximal end of the stent graft ofFIGS. 1 and 70 is included next toFIG. 74. The unconnected portions ofapices1132 need not have the same longitudinal lengths. Depending on the application, one or some of the unconnected portions ofapices1132 can have a longitudinal length different from other ones of the unconnected portions ofapices1132.FIG. 75, for example, illustrates an embodiment near the maximum longitudinal length of the unconnected portion of theclasping stent1130.
• FIGS. 76 and 77 illustrate a proximal end of thestent graft1100 ofFIG. 71 partially deployed from the flexibleinner sheath652. As can be seen inFIG. 76, the entire capturing assemblies of theapex capture device634 reside inside thestent graft1100 when the apices are captured. Only the distal-most portion of thedistal apex head636 extends out from the interior of thestent graft1100. With regard to the view ofFIG. 77, it can be seen that only a few of theapices1132 of theclasping stent1130 are actually held by theapex capture device634.
• It is noted at this point that implantation of thestent graft1,1000,1100 of the present invention occurs while blood is flowing from the heart of the patient. Accordingly, thestent graft1100 cannot occlude the vessel in which it is to be implanted and, in order to do so, there must exist a lumen for passing blood throughout the time after thestent graft1100 has partially or fully expanded within the vessel. If all of theapices1132 of theclasping stent1130 were held within theapex capture device634, then there is a possibility of occluding the vessel if the unattached portion of theapices1132 are too short to provide such a lumen. To avoid this condition, if only someapices1132 of theclasping stent1130 are captured, as illustrated inFIG. 77, then a sufficiently large lumen exists to allow blood flow through the vessel in which the stent graft is to be implanted. Alternatively, if a large percentage of theapices1132 are left unconnected, as shown, for example, inFIG. 75, then all of theapices1132 can be releasably held by theapex capture device634 while thegraft sleeve1110 remains entirely open to allow blood flow through thestent graft1100 during thestent graft1100 implantation process.
• There exists a drawback to placing theclasping stent1130 as the proximal stent of thestent graft1100 because material of thegraft1110 is proximal of theclasping stent1130. If unsupported, this material could move disadvantageously toward the interior of thestent graft1100 after implantation and decrease or occlude blood flow. To prevent such movement, thestent graft1100 also includes acrown stent1140. Like theclasping stent1130, thecrown stent1140 is shown inFIGS. 71,72,74 to76, and78 as being attached to the inside of the graft1120 and, in this exemplary embodiment, is sewn to the material of the graft using the same polyester suture as the other stents. Of course, thecrown stent1140 can be attached to the exterior of thegraft1010. In such a configuration, thecrown stent1140 augments the rigidity of the material of the graft1120 to reduce enfolding thereof at the proximal end of thestent graft1100.
• Alternatively and/or additionally, a non-illustrated distal crown stent can be attached to the inside or outside of the graft1120 at the opposite distal end of thestent graft1100. In such a configuration, thisdistal crown stent1140 augments the rigidity of the material at the distal end of the graft1120 to reduce enfolding thereof.
• The material of the graft1120 can extend and bridge the entire distance between twoproximal crown apices1122. It is noted, however, that, alternatively or additionally, the material of the graft1120 may be partially cut out betweencrown apices1122 of thecrown stent1140 to define a plurality of a radiallydistensible flange portions1124 at the proximal end of thestent graft1100, as shown inFIG. 74.
• There are various advantages provided by thestent graft1100 over the prior art. First, the clasping andcrown stents1130,1140 improve the apposition of the material of the graft to the intima of the vessel in which thestent graft1100 is placed, in particular, in the aorta. Second, by better aligning the proximal portion of thestent graft1110 in the lumen of the arch, the clasping andcrown stents1130,1140 provide an improved blood-tight closure of the proximal end of thestent graft1110 so that blood does not pass between the intima of the vasculature and the outer surface of thestent graft1110.
• As set forth above, if theapex capture device634 captures less than all of the apices of theclasping stent1130. The resulting openings allow blood flow during implantation. It is illustrated particularly well inFIGS. 1,13,14, and70 that the material of thegraft10 ofstent graft1,1000 begins only distal of the center of thebare stent32. In comparison, as shown inFIGS. 71 and 73, the material of the graft1120 begins well proximal of the proximal-most apices of theclasping stent1130. Thus, this embodiment allows the material of the graft1120 to extend much further into a vessel (i.e., further into the curved arch of the aorta). Therefore, a physician can repair a vessel further upstream in the aorta than the embodiment of thestent graft1,1000 ofFIGS. 1 and 70.
• In the prosthesis embodiment ofFIGS. 1 and 70, there is direct contact between the metal of thebare stent32 and the intima of the blood vessel. In contrast thereto, the configuration of thestent graft1100 with theclasping stent1130 places material of the graft1120 between the metal of theclasping stent1130 and the intima. Such a configuration provides a more atraumatic connection between the vessel and the proximal end of thestent graft1100 than the configuration ofFIGS. 1 and 70. This advantage is especially important for treating dissections—where the intima is in a weakened condition.
• FIG. 63 illustrates interaction between thecatheter660, theinner sheath652, and the nose cone assembly630 (including thenose cone632, thedistal apex head636, and the proximal apex body638). In this illustration, first, thecatheter660 is in a proximal position that does not cover theinner sheath652 in any way. For example, this position of thecatheter660 occurs when theinner sheath652 has extended out of thecatheter660 as shown inFIGS. 20 and 21.
• Next, theinner sheath652 is clearly shown in its expanded state (caused by the non-illustrated prosthesis disposed therein and expanding outward). The distal-most end of theinner sheath652 is disposed between thedistal apex head636 and thenose cone632. In such an orientation, theinner sheath652 is in the position that occurs during extension out of thecatheter660 as shown for example, inFIGS. 20 and 21. Because thenose cone632 screws onto the distal end of thedistal apex head636, the distal-most end of theinner sheath652 is releasably captured between the twoparts632,636 until it is removed. Retraction of thesheath lumen654 proximally pulls the distal-most captured end of theinner sheath652 out from the capturing interface.
• Finally, the proximalapex body638 is in a refracted position proximal of thedistal apex head636. This orientation is for illustrative purposes only to show the interaction of thedistal apex head636 and the proximalapex body638 because the separation would not occur in use until, as set forth above, theinner sheath652 is fully retracted from over the stent graft1 and theproximal apices32 of thestent30 have been released as shown inFIG. 14.
• FIG. 80 is a cross-section through thecatheter660, the fingers of the proximalapex body638, the distalapex body636, theapex release lumen640, and theguidewire620.FIG. 81 is a cross-section of the distal end of the delivery system along the longitudinal axis of the delivery system. These two figures illustrate thespace662 that exists between thecatheter660 and both of the proximalapex body638 and the distalapex body636 to make room for theinner sheath652 to surround theparts636,638 and pass between thenose cone632 and thedistal apex head636 and enter thepass664 that allows theinner sheath652 to be releasably held there as shown inFIG. 63 until it is desired to remove theinner sheath652 therefrom.
• FIG. 82 shows a distal end of the delivery system according to the invention in the orientation ofFIGS. 20 and 21, for example. Theinner sheath652 is curved and has an alternative embodiment of a D-shapedmarker234 thereon. In contrast to the configuration of twomarkers234 on the stent graft1 as shown inFIGS. 27 and 28, there is only onemarker234 on theinner sheath652. As illustrated in the orientations ofFIGS. 83,84, and85, themarker234 allows the user to see how theinner sheath652 should be oriented prior to implantation.
• FIGS. 86,87,88, and89 illustrate an alternative embodiment of thefront handle672 that is rotatably attached to thehandle674 and rotatably fixed to thecatheter660.
• FIGS. 90 to 119 depict another exemplary embodiment of various features of thedelivery assembly600.
• FIG. 90 shows theentire delivery assembly600 with a portion ofnose cone assembly630 removed to reveal thedistal apex head636.
• On the proximal end of thedelivery assembly600, the enlarged view ofFIG. 91 depicts an alternative embodiment of theapex release assembly690. InFIG. 91, a proximalpusher support tube645 surrounds two coaxial lumens, theguidewire lumen620 and theapex release lumen640. The proximalpusher support tube645 is longitudinally fixed to the proximal end of thegraft push lumen642 and has substantially the same diameter as thegraft push lumen642. Because the proximalpusher support tube645 is used for pushing/pulling thecombination lumen642,645, and due to the fact that the proximalpusher support tube645 only resides within the handle body or proximal thereof, the proximalpusher support tube645 can be made of a relatively stiff material, such as stainless steel, for example. In contrast, thegraft push lumen642 needs to flex and bend when extending out of theouter catheter660 and into vasculature. Thus, thegraft push lumen642 is made from a relatively flexible material, such as a plastic. InFIG. 91, the proximal portion of the proximalpusher support tube645 is cut away to reveal the features therein, including theguidewire lumen620 and theapex release lumen640.
• Theapex release lumen640 is axially fixed to the proximalapex body638. Theguidewire lumen620, on the other hand, is axially fixed to thedistal apex head636. Thus, distal movement of theapex release lumen640 with respect to theguidewire lumen620 separates the tines of the proximalapex body638 extending over the spokes of thedistal apex head636. To effect this relative movement, proximal and distal crimpingdevices621 and641 are respectively attached to theguidewire620 and theapex release lumen640. Thedistal release part692 is connected, through a non-illustrated set screw, to the distal crimpingdevice641. Theproximal release part694 is connected, also through a non-illustrated set screw, to the proximal crimping device621. Finally, aproximal luer connector800 is connected to the proximal-most end of the proximalpusher support tube645 so that all of thelumen620,640,645 can be filled and/or drained with a liquid, such as saline.
• FIG. 92 is an enlarged view of the alternative embodiment of the lockingknob582 first shown inFIGS. 50 and 51. To better explain the features ofFIG. 92, reference is made to the separatedclasp sleeve614 ofFIG. 93, which was first depicted inFIGS. 50,53, and59 to62. Thisclasp sleeve614 is longitudinally fixedly and rotationally freely connected to thehandle body674 through thesetscrew584 that protrudes into theslot675 of thehandle body674. Thesetscrew584 is screwed into but not through the proximal end of the clasp sleeve as shown inFIG. 93, for example. Thissetscrew584 protrudes into theslot675 in thehandle body674. When so connected, theclasp sleeve614 cannot move longitudinally with respect to thehandle body674 but can rotationally move along the are defined by the length of theslot675. Thesetscrew584 protrudes from the outer circumference of thehandle body674 because it enters into thelongitudinal slot583 in the lockingknob582. Thus, thesetscrew584 also controls the longitudinal movement distance of the lockingknob582. When theknob582 is at rest, thesetscrew584 resides in the distal end of theslot583 because of the bias caused by spring607 (seeFIG. 94).
• The second setscrew592 (also referred to as a position pin) starts from thehandle body674 but does not extend inside thehandle body674. Thesetscrew592 does, however, protrude out from thehandle body674 and into the three-position slot587 of the lockingknob582. Thus, thesetscrew592 controls the rotation of theknob582 within the three positions.
• Thethird setscrew585 is screwed through a threaded hole in thehandle body674 and into a co-axial threadedhole6021 of theclasp body602 until thesetscrew585 is even with the exterior surface of thehandle body674. Thus, thesetscrew585 does not protrude from the outer circumference of thehandle body674.
• Theproximal clasp assembly604 was first illustrated inFIG. 52. InFIG. 94, theproximal clasp assembly604 is illustrated with different detail. Theclasp body602 has a distalinterior cavity6023 shaped to receive therein the distalclasp body spring606, which is a torsion spring in this exemplary embodiment. The lockingwasher608 is connected to the distal end of theclasp body602 by a non-illustrated setscrew that, for example, runs through the bore illustrated at the 12 o'clock position on the lockingwasher608 inFIG. 94. To keep the clasp body assembly pressed into theclasp sleeve614, as shown inFIGS. 101 and 102 for example, adistal spring washer605 and aproximal compression spring607 are inserted into a proximalinterior cavity6024. Placement of the lockingknob676 onto thehandle body674, as shown inFIG. 92 for example, compresses thecompression spring607 between the lockingknob676 and the proximal surface of thespring washer605 residing inside the proximalinterior cavity6023 of theclasp body602. This compression forces theknob676 proximally to keep thespring592 inside the three-position slot675. Thespring washer605 is present to prevent thespring607 from binding when the lockingknob676 is rotated between the three rotational positions. The smooth surface of thewasher605 does not catch the distal end of thecompression spring607 when thespring607 rotates.
• The rotator assembly includes thepusher clasp rotator292, thepusher clasp spring298, and therotator body294. These parts are first depicted inFIGS. 34 to 43 and47 to48 and are next depicted inFIGS. 95 and 96. InFIG. 95, the rotator assembly is illustrated in an exploded, unassembled state andFIG. 96 shows the assembly in an assembled state. When assembled, the two protruding ends of thepusher clasp spring298 are respectively inserted into thelongitudinal slots2942 and2922 of each of therotator body294 and thepusher clasp rotator292. Because the distal end of therotator body294 is smaller in diameter than the cavity of thepusher clasp rotator292, the end of the spring that fits inside theslot2922 must be longer than the end of thespring298 that fits inside theslot2942 of therotator body294.
• Therotator body294 is secured inside thepusher clasp rotator292 by twodowels2926 that are press fit through a first orifice in theclasp rotator292 after therotator body294 is inside theclasp rotator292. Thesedowels2926, then, pass through acircumferential groove2944 substantially without touching the walls of thegroove2944 and, then, through a second orifice in theclasp rotator292 directly opposite the first orifice. In such a configuration, therotator body294 is longitudinally fixed but rotationally free inside theclasp rotator292. The first and second orifices and thegroove2944 are clearly shown inFIG. 113 (with thedowels2926 removed for clarity).
• FIGS. 44 to 48 illustrated thepusher clasp body296 and its relationship with thesheath lumen654.FIGS. 97 and 98 further illustrate two views of thepusher clasp body296 and itsdistal projection297. The proximal end of thesheath lumen654 passes through thecrimp ring295 and over thedistal projection297. Then, to secure thesheath lumen654 to thepusher clasp body296, thecrimp ring295 is compressed/crimped. Such a connection both longitudinally and rotationally stabilizes thesheath lumen654 with respect to thepusher clasp body296. Two pins2962 hold thepusher clasp body296 to theproximal handle678 so that longitudinal movement of theproximal handle678 translates into a corresponding longitudinal movement of thepusher clasp body296 within thehandle body674. These pins2962 pass through a plug2964, shown in FIG.114, and then into thepusher clasp body296. The length of the pins that exist through the plug2964 and also through thepusher clasp body296 gives enough support to prevent movement of thehandle678 from breaking the pins2962, which might occur if the plug2964 were not present.
• It is noted that the conical expansion of the proximal end of theinner sheath652 is different inFIGS. 97 and 98. This is because the embodiment shown inFIGS. 97 and 98 illustrates an expansion portion of theinner sheath652 that is sutured on only one side thereof. Accordingly, when viewed along the suture line (as inFIG. 98), the cone has one flat side. In contrast, when viewed in an elevation 90 degrees turned from that suture line (as inFIG. 97), the expansion portion has a conical elevational view.
• Also shown inFIG. 98 on theinner sheath652 is a D-shapedradiopaque marker232. Thismarker232 is enlarged inFIG. 99 and can be, for example, secured to theinner sheath652 by three sutures, diagrammatically indicated with an “X.”
• FIG. 100 is an enlarged view of the distal end of the handle assembly670 shown inFIG. 90. This embodiment of thedistal apex head636 shows an alternative embodiment of the proximal portion that was first shown inFIG. 29. As can be seen in the drawing, the proximal side of thedistal apex head636 is tapered. This tapered shape allows thedistal apex head636 to enter further into the interior cavity between the prongs of the proximalapex body638 than thedistal apex head636 shown inFIG. 29. It is noted that the portion of the delivery system at the distal end is to be flexible so that this portion can traverse curved vessels. Thus, it is desirable for the length of thedistal apex head636 and the proximal apex body638 (semi-rigid parts) to be as short as possible. By allowing thedistal apex head636 to travel further into the proximalapex body638, the longitudinal length of the twoparts636 can be shorter.
• Now that the various parts of the handle assembly670 have been shown and described separately, the interactions and orientations when assembled can now be further understood with reference to the following description and toFIGS. 101 to 105.
• FIGS. 101 to 102 show the proximal half of the handle assembly670 from just proximal of the lockingknob676 to just distal of the distal end of the proximal handle678 (when thehandle678 is in a proximal position). The hidden lines shown inFIG. 101 aid in the understanding of this portion. It is noted that thesheath lumen654 is not illustrated inFIG. 101 for clarity.
• FIG. 102 clearly shows the components that are involved in the proximal half of the handle assembly670. Thehandle body674 is surrounded by thedistal handle678 and a portion of the lockingknob676. Inside the proximal end of thehandle body674 is theclasp body602, which is surrounded by the proximal end of theclasp sleeve614. The lockingwasher608 is positioned inside theclasp sleeve614 at the distal end of theclasp body602.
• Separated at a distance from the distal end of the lockingwasher608 is the rotator assembly, which, as set forth above, is longitudinally fixed to theproximal handle678. The rotator assembly includes thepusher clasp rotator292 surrounding thepusher clasp spring298 and therotator body294. Thepusher clasp body296 is disposed on the distal end of therotator body294 and thecrimp ring295 secures thesheath lumen654 on thedistal projection297 of thepusher clasp body296.
• FIG. 103 is an enlarged view of the proximal portion ofFIG. 102 by the lockingknob676. These figures show the alignment of the bores in theclasp body602 and the lockingwasher608 so that the non-illustrated setscrew can fasten the two parts to one another. Also shown inFIG. 103 is the alignment between thegroove605 for receiving therein the setscrew586 (seeFIGS. 53 and 93) and connecting theproximal clasp assembly604 to theclasp sleeve614 so that theclasp sleeve614 can still rotate around theclasp body602. Also visible in the enlarged view ofFIG. 103 is the threecoaxial lumen620,640,645 that pass through theclasp body602.
• LikeFIG. 103,FIG. 104 is an enlarged view of the distal portion of the handle assembly670 around thepusher clasp rotator292. This view not only shows the orientations of therotator body294 and thepusher clasp body296 with respect to thepusher clasp rotator292, but the three coaxial lumen passing therethrough are also evident. Thegroove2944 for receiving thenon-illustrated dowels2926 therein is also visible in this view. As can be seen, theguidewire lumen620 and theapex release lumen640 each pass entirely through thepusher clasp body296 but the proximalpusher support tube645 ends just after the distal end of therotator body294 for homeostasis purposes. It is at this end point that the proximalpusher support tube645 is connected to thegraft push lumen642. This two-part structure of the proximalpusher support tube645 and thegraft push lumen642 is, in an exemplary embodiment, a bonding of a proximalstainless steel lumen645 and aplastic lumen642, for example, a polyurethane-based extrusion. As set forth above, arigid lumen645 in the handle portion keeps rigidity there and aflexible lumen642 distal of thedistal handle672 allows the lumen to flex as needed. The distal end of therotator body294 is also fluidically sealed off from the interior of the distal interior of the delivery system with a hemostasis o-ring293.FIG. 105 is still a further enlarged view around thepusher clasp spring298.
• A transverse cross-sectional view through the handle assembly670 is illustrative of the interaction between and relationship of various components of this assembly670. The cross-sections shown inFIGS. 106 to 118 progress from proximal to distal.
• A first transverse cross-section through thelongitudinal slot583 of the lockingknob676 is illustrated inFIG. 106. In this cross-sectional plane, theclasp body602 is shown as filling up most of the interior of theclasp sleeve614. The anchoring bore in theclasp sleeve614 for thesetscrew585 is shown aligned with theslot583.
• A second transverse cross-section through the three-position slot587 of the lockingknob676 is illustrated inFIG. 107. In this cross-sectional plane, theclasp body602 still is shown as filling up most of the interior of theclasp sleeve614. Theslot6022 of theclasp body602 for receiving one end of thetorsion spring606 is also depicted inFIG. 107.
• A third transverse cross-section through theclasp body602 before the lockingwasher608 is illustrated inFIG. 108. In this cross-sectional plane, theslot6022 of theclasp body602 is aligned with aslot6143 inside the proximal end of theclasp sleeve614 that is not visible inFIG. 93 but is visible through the cutout inFIGS. 59 and 60. This alignment is merely shown inFIG. 108 for understanding the different depths of theseslots6022,6143. Like thepusher clasp spring298, the distalclasp body spring606 has ends with different lengths. The first, shorter, end is inserted into theinner slot6022 of theclasp body602 and the second, longer end is inserted into theslot6143 of theclasp sleeve614.
• The fourth transverse cross-section between theproximal clasp assembly604 and the rotator assembly shows, inFIG. 109, the spatial separation of these two assemblies that is depicted, for example, inFIGS. 101 to 102. Visible in these figures is thelongitudinal slot6141 that, as shown in11 in the cross-sections ofFIGS. 110 to 111, guides the movement of thepusher clasp rotator292 by delimiting a space that corresponds to the width of theboss2924 that extends out from the outer circumferences of thepusher clasp rotator292. Thisslot6141 allows thepusher clasp rotator292 to move longitudinally freely with respect to theclasp sleeve614; simultaneously, this connection prevents any rotation of thepusher clasp rotator292 that is independent from rotation of theclasp sleeve614. Accordingly, as theclasp sleeve614 rotates about its longitudinal axis, thepusher clasp rotator292 will rotate as well. The further enlarged view of the center of the configuration illustrated inFIG. 110 is depicted inFIG. 111. Here, the rotator assembly portions are clearly shown with thepusher clasp spring298 therebetween.
• The sixth cross-section ofFIG. 112, and the enlarged view of the sixth cross-section inFIG. 113, illustrate the longitudinally fixed but rotationally free connection between thepusher clasp rotator292 and therotator body294. The two bores in thepusher clasp rotator292 for receiving the dowels2926 (not illustrated here) are clearly shown to intersect the open space in thegroove2944 of therotator body294.
• A seventh cross-section inFIG. 114 shows the connection of thepusher clasp body296 and theproximal handle678 through the plug2964. This view also depicts the fluid communication between the interior of the handle assembly670 and theluer fitting612. When theluer612 is connected to a fluid supply, the flushing liquid enters the interior cavity distal of therotator body294 and sealed off by the o-ring293 and purges all air therein at the distal end of the delivery system.FIG. 114 also shows thegraft push lumen642 extending through thehandle body674 beginning after the distal side of the o-ring293.
• The eighth cross-section ofFIG. 115 illustrates thedistal projection297 at which thecrimp ring295 holds thesheath lumen654 onto thepusher clasp body296. This figure also illustrates the open radial space between theclasp sleeve614 and thegraft push lumen642. To keep the relatively long extent of the flexibleinner lumen620,640,642 passing through the open interior of thehandle body674 from moving out of a centered orientation (i.e., from bending out from the longitudinal axis of thehandle body674, slidingspacers6142 are periodically provided along theclasp sleeve614 as shown inFIGS. 93 and 116 to118. Thesespacers6142 are only needed while theproximal handle678 is moving the rotator assembly and thepusher clasp body296 in a distal direction to prevent bending of the interiorflexible lumen620,640,642. Accordingly, thespacers6142 can slide within thegroove6141 of theclasp sleeve614 up to and over the distal end of the clasp sleeve614 (the right side of thesleeve614 as viewed inFIG. 93; see alsoFIG. 117). Each of thesespacers6142 is self secured in a slidable manner to theclasp sleeve614.
• FIG. 117 depicts a ninth cross-section through a distal end of theclasp sleeve614 within thedistal handle672. Thedistal handle672 freely rotates about thehandle body674 in an exemplary embodiment. In such an embodiment, theouter catheter660 will also freely rotate about all of thelumen620,640,642 therein because of the fixation between theouter catheter660 and thedistal handle672. SeeFIG. 118.
• The shaded parts inFIG. 119 are provided to show portions of the features around theclasp body602. In this view, the rotator assembly is removed.
• The following text describes the four movements for implanting a prosthesis with the delivery system and the relative connections between relevant lumens when in the three different settings of the lockingknob676.
• The first movement will be referred to as the advancement stage and utilizes position1 of the lockingknob676. When in position1, thedistal spring298 is engaged around and holds the pusher support tube645 (and, therefore, graft push lumen642) to therotator assembly292,294. Thisassembly292,294 is fixed at the distal end of therotator body294 inside the pusher clasp body296 (through a non-illustrated setscrew passing through the threadedbore2966 shown inFIG. 98). As set forth above, thepusher clasp body296 is fixed to theproximal handle678 and, therefore, the pusher support tube245 moves with theproximal handle678 in position1.
• In this first movement, the entire distal assembly is advanced up to the implantation site using theproximal handle678. Thus, when thehandle678 moves distally, all of the lumen, including theguidewire lumen620, theapex release lumen640, thegraft push lumen642/proximalpusher support tube645, and thesheath lumen654, are locked together and move distally with a corresponding movement of theproximal handle678. As theouter catheter660 is longitudinally fixed to thedistal handle672, it remains longitudinally fixed during the first movement. The lumen displacement in the advancement stage is depicted inFIGS. 19 to 21.
• The second movement will be referred to as the primary deployment stage and utilizesposition2 of the lockingknob676. When inposition2, thedistal spring298 is disengaged from thepusher support tube645 and theproximal spring606 becomes engaged around thepusher support tube645 to anchor only the push rod642 (withoutlumen620,640) to theproximal handle678 and allow retraction of sheath lumen654 (and, thereby, the inner sheath652) while all other lumens are disengaged and remain stationary.
• In this second movement, theinner sheath654 needs to be moved in the proximal direction, as shown inFIGS. 22 to 24. Accordingly, when thehandle678 moves distally, only thesheath lumen654 moves with thehandle678. Thus, inposition2 of the lockingknob676, thesheath lumen654 is locked to theproximal handle678 and moves proximally with a corresponding movement of theproximal handle678; all of the other lumen, including theguidewire lumen620, theapex release lumen640, and thegraft push lumen642/proximalpusher support tube645, are unlocked and remain in the distally deployed position. SeeFIGS. 22 to 24.
• The third movement will be referred to as the final deployment stage because, in this movement, theapex capture device634 completely releases the distal end of the prosthesis as shown inFIG. 14. Here, theapex release lumen640 is unlocked (using the release mechanism ofFIG. 91) with respect to theguidewire lumen620 and thegraft push lumen642/645.
• The fourth movement will be referred to as the extraction stage and utilizes position4 of the locking knob (the third of the three positions in theslot587 of the locking knob676). When in position4, both thedistal spring298 and theproximal spring606 are disengaged from thepusher support tube645 to allow the user to pull the proximal end of thepusher support tube645 and withdraw it from the implantation site. The entireinner lumen assembly620 and640 travels with the proximal movement of thepusher support tube645 because the release mechanism (seeFIG. 91) is pulled with thesupport tube645 as it moves proximally.
Self-Centering Tip
• As set forth above, thebare stent30 provides an outward, expanding force at theproximal end12. Thebare stent30 and theproximal stent23 are in a compressed state when attached to thegraft sleeve10 and also provide an outward, expanding force to thegraft sleeve10. Therefore, when implanted, these forces center the proximal end of the stent graft1 in the vessel and press thegraft sleeve10 against the vessel wall to prevent leaks that might occur between thegraft sleeve10 and the vessel wall. Such leaks at theproximal end12 are to be avoided in stent graft implantation.
• Because some physicians are concerned that the bare stent could damage the aortic wall, especially in the case of aortic dissection, they prefer to use a stent graft without a bare stent, such as thestent graft1100 shown inFIGS. 72 and 74 to77. In this configuration, theproximal end12 can travel further upstream in the aorta and, in doing so, place thegraft sleeve10 closer to the heart. Such an implantation has various advantages, such as the removal of the possibility of bare stent puncture or damage to the vessel and the ability to treat diseased portions of the aorta closer to the heart.
• However, if thebare stent30 is removed, the ability to center theproximal end12 is affected. One deficiency of thoracic grafts not having a bare stent is a misalignment of the proximal end of the prosthesis with the aortic curvature, which leads to improper apposition of the proximal end of the graft with the aortic arch inner curvature. Proper apposition is a desirable characteristic.
• Stent grafts, by their nature of replacing the through-conduit of a damaged tubular vessel, have aproximal opening12 for receiving therein the incoming fluid previously carried by the damaged vessel. See, e.g.,FIG. 1. It is desirable to directly contact the entire perimeter of this opening to the inside surface of the vessel in which the stent graft is to be placed because an opening between the proximal end of the stent graft and the vessel wall would allow a secondary flow outside and around the stent graft. This bypassing secondary flow is to be avoided when implanting stent grafts in a vessel and is particularly undesirable when implanting a stent graft in the aorta. The present invention provides a device, system and method for reducing and/or eliminating the possibility of such a bypassing flow by placing theproximal end12 in a desired position within the vessel.
• For the purposes of discussion, a few terms will be defined. The plane intersecting the proximal end opening of a stent graft is referred to herein as the inflow plane. The ring of tissue inside the vessel at which the proximal end opening is to be implanted is referred to herein as an upstream implant ring. The plane in which the upstream implant ring resides in the vessel is referred to herein as the implant plane. A longitudinal tangent is referred to herein as a line that is orthogonal to the implant plane at a point on the upstream implant ring.
• A most-desirable implantation of the stent graft occurs when the inflow plane and the implant plane are co-planar. In this orientation, the longitudinal tangent of each point along the upstream implant plane is orthogonal to the inflow plane. This means that the outward force imparted by the proximal end of the stent graft is along a line that is co-planar with the implant plane, thereby insuring that the fluid-sealing force of the proximal end is maximized at the upstream implant ring.
• When a stent graft is implanted in a longitudinally straight vessel, the inflow plane and the implant plane are virtually co-planar. In this orientation, a maximum outward sealing force is established at each point on the upstream implant ring, thereby maximizing the possibility of creating a permanent fluid-tight seal along the entire perimeter of the upstream implant ring.
• When a stent graft is to be placed in a longitudinally curved vessel, as shown inFIGS. 19 to 24 and65 to67, for example, co-planar alignment of the implant plane and the inflow plane does not occur naturally. In fact, prior art stent grafts and delivery systems could not establish this co-planar alignment of the implant plane and the inflow plane when the stent graft was placed in a curved vessel. As such, when the stent graft was implanted in the curved vessel, the inflow plane was left at an angle to the implant plane, which, in turn, created a gap at the inferior side of the curved vessel. In some instances, this gap allowed fluid to flow impermissibly around the implanted stent graft.
• One of the primary reasons for this misalignment is due to the behavior of the guidewire within the curved portion of the vessel. Theguidewire610 does not remain centered within the vessel throughout the curved portion of the vessel—as illustrated diagrammatically inFIGS. 19 to 24 and65 to67. Instead, in practice, theguidewire610 tracks toward the superior (outside) curve from approximately the center axis of the vessel until it actually contacts the interior of the superior curve at least at one point within the curved vessel. The curved guidewire, therefore, not only guides the stent graft towards the superior curve, it does so while imparting an outwardly directed force to the stent graft—a force that naturally moves the stent graft off center in the curved vessel.
• This non-axial tracking of theguidewire610 is diagrammatically shown inFIG. 120. Here, theinflow plane300 and theimplant plane400 are at an angle α to one another. Because the diameter of theupstream implant ring12 has a maximum length that is defined by the opening of the graft material, an inferior gap appears between the inferior curved vessel wall and theupstream implant ring12. The present invention provides devices and methods for automatically centering thestent graft1100 within the vessel and, thereby, substantially align theimplant plane400 with theinflow plane300 as shown inFIG. 121. As used herein, substantial alignment of theimplant plane400 and theinflow plane300 is an angular difference of less than 15 degrees between the two planes.
• A first exemplary embodiment of the device that improves proximal end apposition when it is placed in the aortic lumen prior to deployment in curved anatomy is illustrated inFIGS. 122 and 123. The previously describedtip632 is altered as shown inFIG. 122. Thenew tip632′ has an overall length that is greater as compared to thetip632. Thedistal section6322′ is tapered similarly totip632. Theproximal section6324′ is straight and, hence, not bendable while tracking over theguidewire610. This stiffproximal section6324′, along with the stiff distal and proximal clasps, produces an elongated stiff region in thenose cone assembly630 of thedelivery system600. This stiff region does not accommodate the superior curvature of the aorta and pushes the distal end of the delivery system down towards the inferior curvature when tracking in curved anatomies.
• FIG. 123 illustrates how a modified tip pushes the proximal end of the stent graft down (as viewed inFIG. 123) towards the inferior curve of the curved aortic lumen. If theproximal end12 of thestent graft1100 is deployed while centered as shown, theproximal end12 will have proper apposition with the aortic wall at the inferior curvature.
• A second exemplary embodiment of the proximal end apposition improvement device is illustrated inFIGS. 124 to 126. In this embodiment, thetip632″ contains therein a set ofballoons6322″ that, when inflated independently, exit and extend from arespective slit6324″. The number of balloons can be 1, 2, 3, 4, or more. In the exemplary embodiments shown, there are three balloons spaced 120 degrees apart from one another. Which balloon(s) that are inflated after thetip632″ is positioned in the curved vessel will depend upon the position of theslits6324″. As shown inFIG. 125, oneballoon6322″ can be inflated to center thetip632″ or, as shown inFIG. 126, all threeballoons6322″ can be inflated.
• A third exemplary embodiment of the proximal end apposition improvement device takes its genesis from thebare stent30. In all of the embodiments for improving apposition, thebare stent30 is removed. Because some physicians are concerned that a bare stent can damage an aortic wall, especially in the case of aortic dissection, the invention proposes creating a bio-absorbable bare stent. Such abare stent30 dissolves over time but ensures proper alignment of the proximal end of the graft during deployment. Because the bare stent is absorbed, any potential for damaging the aortic wall is eliminated.
• A fourth exemplary embodiment of the proximal end apposition improvement device is illustrated inFIGS. 127 and 128. A dual-cone410 device centers thenose cone assembly630 of thedelivery system600 within the lumen. Centering the nose cone assembly within the aortic lumen, in turn, will ensure that the proximal end of thestent graft1100 is properly aligned with the aorta. The dual-cone device can be made of silicone. The bases of the two opposing conical parts are adjacent one another. When the ends of the conical parts are pressed towards one another, the diameter of the conical base increases. As the base increases in diameter, its circular expansion comes in contact with the superior curve of the aortic wall to force thenose cone assembly630 towards the center of the aortic lumen. When fully expanded, the proximal end13 of thestent graft1100 is in a desired centered position and is, therefore, ready for deployment. It is noted that the shape of the conical components can be modified to allow greater expansion of the conical base at specific locations.
• A fifth exemplary embodiment of the proximal end apposition improvement device is illustrated inFIGS. 129 and 130. This centering system uses a pull-wire420 that can center the tip end of the delivery system within the aortic lumen. The pull-wire420 resides inside the delivery system between thestent graft1100 andinner sheath652. One end of the pull-wire420 can be attached to thenose cone assembly630, for example, the proximalapex body638 and the other end of the continuous wire is attached to a mechanism at the proximal portion of thedelivery system600, whether at the proximal end of the handle assembly670 or at theapex release assembly690. This mechanism, when operated, pulls the wire proximally to produce a force P having two resultant forces P′ and P″ shown inFIG. 130. even though P′ is the smaller of the two resultant forces, if force P is large enough, P′ will pull the tip towards the inferior curve of the aorta.FIG. 129 illustrates the distal end of the delivery system being centered by pulling on the wire520 to create centered apposition of theproximal end12 of thestent graft1100.
• A sixth exemplary embodiment of the proximal end apposition improvement device is illustrated inFIGS. 131 and 132. Theapex clasp device636,638 is formed in two halves or three thirds. In this configuration, the split clasp mechanism allows angular adjustment of the proximal end of the graft within the aortic lumen to insure optimum apposition with the aortic wall as shown in the comparison ofFIGS. 131 and 132. The split clasp allows the user to move forward and backward some specific apices along the proximal circumference of thestent graft1100 which, in turn, changes the angle of theinflow plane300 with respect to theimplant plane400. By using this process and system, the physician can adjust the orientation of theproximal end12 to ensure proper apposition against the aortic arch inner curvature.
• A seventh exemplary embodiment of the proximal end apposition improvement device is illustrated inFIGS. 133 to 135. As set forth above, theapex clasp device636,638 uses a set of distally projecting fork tines and an internal castellated portion to create openings in which theproximal apices32 of thebare stent30 or theproximal apices1132 of theclasping stent1130 are held releasably. Instead of theapex clasp device636,638, each of theapices32,1132 are individually held with an apex capture mechanism that is shown inFIGS. 133 to 135. Pushing the wire in one of the apex capture mechanisms causes theproximal end12 of thestent graft1100 to move. A combination of such pushing forces on one or more of these apex capture mechanisms will cause theproximal end12 to move into a desired apposition of theinflow plane300 and theimplant plane400. When the wires are pulled, they move proximally and release the capture of therespective stent apex32,1132.
• An eighth exemplary embodiment of the proximal end apposition improvement device is illustrated inFIGS. 136 to 142. Here, thetip632 has slots through which extend loops of wires that, when extended as shown inFIGS. 137,141, and142, center thetip632 within the vessel in which it is placed. The mechanism is composed of wires that are contained inside the slots in a straight configuration. Compressing the wires causes them to protrude from the slots and form loops that can press against the vessel wall, thereby centering thetip632 within the vessel. Extension of the loops can be actuated through a single pull mechanism, for example, with a telescoping slide. Centering of the tip is actuated by pulling on a knob (for example) located at the proximal end of the delivery system. The knob is connected to the wire loops by a catheter that extends from the knob to the distal end of the loops. The loops, in turn, are fixed at their distal end. Pulling on the knob would cause the catheter to slide in a proximal direction causing a compression of the wire loops, making them protrude from thetip632 as shown inFIGS. 137,141, and142. In addition, the catheter can contain a component that engages the clasp as it is moved proximally. Thus, as the catheter is moved, at approximately three-fourths of the actuation stroke, the component on the catheter engages the clasp and with the remainder of knob retraction the clasp would be released.
• A ninth exemplary embodiment of the proximal end apposition improvement device is illustrated inFIG. 143. In this approach, anaccessory device430 is introduced into one or more of the contra lateral limbs of the patient or radially through the arm. Before, during or after, the delivery system is used to extend the aortic stent graft into the aortic arch for implantation. Theaccessory device430 is, then, extended into the aortic arch and pressed against a portion of the delivery system. For example, as shown inFIG. 3, theaccessory device430 can be introduced through the left sub-clavian artery and used to bias the delivery catheter away from the greater curve of the arch. Theaccessory device430 can have many forms. It could be a balloon, a mechanical mechanism, and a pusher from the trans-femoral approach, a balloon or a mechanical mechanism is practical. Each of these concepts can be applied in a direct approach from the left sub-clavian artery or the Brachiocephalic Trunk.
• A tenth exemplary embodiment of the proximal end apposition improvement device is illustrated inFIGS. 144 to 146. In this embodiment, the properties of temperature sensitive nickel-titanium are combined with the technology of localized heating to present a controlled shape manipulation. Shape memory bends are imparted to portions of thedelivery system600 prior to incorporation in thedelivery system600. Then, the portions are placed into the desired configuration, e.g., linear, and incorporated into thedelivery system600.Heater bands440 are distributed along thedelivery system600 adjacent the memory bends. As shown inFIGS. 144 to 146, application of heat at the memory bends will cause the adjacent portion of thedelivery system600 to bend. If the bends are coordinated, they can be made to bend the in-vivo delivery system600 in any desired way, in particular, to center the tip in the vessel and, thereby, implant theproximal end12 of thestent graft1100 with a proper apposition. Alternatively, ultrasonic sensitive crystals can be used as the heater bands. Thus, when energy is applied, the crystal heat up and cause the nickel-titanium memory portion to bend into their pre-programmed memory shape.
• An eleventh exemplary embodiment of the proximal end apposition improvement device is illustrated inFIGS. 147 to 151. In this embodiment, a hollowballoon delivery catheter450 having aballoon configuration452 is provided. Theballoon delivery catheter450 has aninterior bore454 through which theouter catheter660, thenose cone assembly630, and theinner sheath652 travel.FIGS. 149 to 151 illustrate an exemplary method for using theballoon delivery catheter450 of the present invention. First, theballoon delivery catheter450 is inserted into at least part of the aortic arch and theballoon configuration452 is inflated to center and hold theballoon delivery catheter450 in position within the aorta. SeeFIG. 147. Then, the distal end of thedelivery assembly600 is passed through theballoon delivery catheter450 as shown inFIG. 148. Theproximal end12 of thestent graft1100 is deployed in the aortic arch and, after satisfactory apposition of theinflow plane300 and theimplant plane400 is verified, theballoon configuration452 is deflated and theballoon delivery catheter450 can be removed. Finally, thestent graft1100 is fully implanted as set forth above.
• In theexemplary balloon configuration652 shown inFIGS. 150 and 151, there are threeballoons452 with spaces therebetween so that blood can flow past theballoons452 when inflated. This tri-balloon device is shown inFIGS. 150 and 151.
• Alternative to theballoon delivery catheter450, aballoon configuration452 can be added at the distal end of theouter catheter660. When theouter catheter660 is at its distal-most position in the aorta, theballoon configuration450 inflates and centers thenose cone assembly630 within the aorta. Thus, when theinner sheath652 containing thestent graft1100 is extended from theouter catheter660, thenose cone assembly630 is centered within the aorta and theinner sheath652 andnose cone assembly630 can be extended within the aortic arch in a centered orientation.
• A twelfth exemplary embodiment of the proximal end apposition improvement device is illustrated inFIGS. 152 to 155. In this embodiment, a balloon delivery rod460 having a balloon configuration462 is provided. The balloon delivery rod460 is inserted into at least part of the aortic arch and the balloon configuration462 is inflated at the superior curve of the aortic arch. SeeFIG. 152. Then, the distal end of thedelivery assembly600 is passed through the aorta and along the inflated balloon configuration462 as shown inFIG. 153. Theproximal end12 of thestent graft1100 is deployed in the aortic arch and, after satisfactory apposition of theinflow plane300 and theimplant plane400 is verified, the balloon configuration462 is deflated and the balloon delivery rod460 can be removed. Finally, thestent graft1100 is fully implanted as set forth above.FIG. 155 illustrates one possible cross-sectional configuration for the balloon462 of this embodiment.
• A thirteenth exemplary embodiment of the proximal end apposition improvement device is illustrated inFIGS. 156 to 158. As described above, aproximal edge12 that is perpendicular to the longitudinal edges (seeFIG. 71) will be difficult to position in a curved vessel and, in such a case, theinflow plane300 will be at an angle to theimplant plane400 as shown inFIG. 157. To counteract this non-apposition of theproximal end12 that does not have a bare stent, thestent graft1100 can be formed with a non-linearproximal end12′ as shown inFIG. 158. With this angled contour, if the shorter side (left side inFIG. 158) is positioned at the inferior curved of the vessel, theproximal end12 will fit inside the aorta to align theinflow plane300 and theimplant plane400 as shown inFIG. 158.
• A fourteenth exemplary embodiment of the proximal end apposition improvement device is illustrated inFIG. 159. Thetip632 or thenose cone assembly630 is configured with asymmetric dilator470 shown inFIG. 159. Thisdilator470, when closed, is merely a cylinder. However, when opened as shown in the figure, the two outer bearing surfaces472 apply pressure to opposing sides of the vessel in which thestent graft1100 is to be implanted, thereby centering thenose cone assembly630 and theproximal end12 within the vessel for implantation with apposition of theinflow plane300 and theimplant plane400.
• A fifteenth exemplary embodiment of the proximal end apposition improvement device is illustrated inFIGS. 160 and 161. In this embodiment, a plurality (e.g., four) ofwires480 are threaded through thedelivery assembly600 and are attached to, for example, four quadrants of theapex capture device634. At the proximal end of thedelivery assembly600 is located an actuation knob or “joystick”482. By pulling or otherwise maneuvering theknob482, tension is applied to one or more of thewires480 and moves thetip632. Such maneuvering is used to center thetip632 as desired to ensure apposition of theinflow plane300 and theimplant plane400.
• A sixteenth exemplary embodiment of the proximal end apposition improvement device is illustrated inFIGS. 162 and 163. Because blood is flowing through an aorta in which astent graft1100 is to be implanted, properties of the flow can be used for making perpendicular the stent graft's proximal opening with the tangent of the aortic arch to provide an optimal proximal seal. In particular, a tapered “windsock”490 can be incorporated into thedelivery assembly600. The proximal diameter of thewindsock490 is large enough so that, upon expansion due to the incoming blood flow, theproximal opening492 of thewindsock490 opens and presses against the aortic wall. In such a configuration, thewindsock490 channels all blood flow therethrough and discharges the flow from adistal opening494. Thedistal opening494 is made to be smaller than theproximal opening492. The change in opening size increases the pressure in thewind sock490. When the blood flow is channeled into a path that is concentric within the aorta, such as through an evenly spaced set ofexit orifices494, the balanced (and centered) pressure would radially center the leading portion of thestent graft1100 during deployment.
• In one exemplary configuration shown inFIG. 162, theproximal end492 of thewindsock490 is attached with sutures to theapex capture device632. Thedistal end492 of thewindsock490 may or may not be attached to a portion of thedelivery assembly600 distal of theproximal end12 of thestent graft1100 to be deployed. CompareFIGS. 162 and 163. It is noted that having no distal attachment (FIG. 163) may be more advantageous because performance of blood flow balancing may be better than with distal attachment (FIG. 162). If thedistal end494 of thewindsock490 is attached, a break-away method for the sutures can be used along with the incorporation of blood flow ports as illustrated inFIG. 162. Performance of thewindsock490 can be evaluated with varying discharge port diameters and overall tapers.
• A seventeenth exemplary embodiment of the proximal end apposition improvement device is illustrated inFIGS. 164 to 169. In this embodiment, a plurality of memory shape metal (e.g., Nitinol) hypo-tubes500 are attached to thedelivery assembly600 and act as a mechanism to center the tip and, therefore, thestent graft1100 during stent graft positioning and deployment. In one exemplary embodiment, two control tubes orlumens502,504 are placed somewhere between, around, or over theapex release lumens620,640. Each of the hypo-tubes500 is secured at itsdistal end506 to theinner control tube502 at or near thetip632. Each of the hypo-tubes500 is further secured at itsproximal end508 to theouter control tube504 at a distance from thetip632. As illustrated in the comparison ofFIGS. 165 and 166, forward (advancement) motion of the outer control tube makes the hypo-tubes500 expand into a “basket” shape that contacts the walls of the aorta and centers theproximal end12 of thestent graft1100 within the vessel. When in this advanced position of theouter control tube504, as shown inFIG. 164, the hypo-tubes500 are used to create an arc during positioning and, thereby, facilitate the centering function. Backwards (refraction) motion of theouter control tube504 decreases the profile of the hypo-tubes500 to lie longitudinally along the length of theinner control tube502.
• To incorporate this feature into the stent grasping device that connects with each of theproximal apices1132 of theclasping stent1130, each hypo-tube500 has a small “notch”510 (slightly larger than the diameter of the wire of theclasping stent1130. This “notch” is located at the center of the pre-formed arc of the hypo-tubes500 (seeFIGS. 166,167). Inside the diameter of the hollow hypo-tube500 is a rigid release wire that acts to engage theproximal apices1132 to attach releasably theclasping stent1130 to the delivery system. See, e.g.,FIGS. 133 to 135. The releasable clasping shown inFIGS. 168 and 169 ensures a secure lock of thestent graft1100 to thedelivery assembly600. During attachment of thestent graft1100 to thedelivery assembly600, theapices1132 of theclasping stent1130 are positioned into eachnotch510 and the rigid release wire is fed over theclasping stent1130 to capture (secure) theclasping stent1130 and secure it to the delivery assembly600 (seeFIG. 169). Release of thestent graft1100 from thedelivery assembly600 is obtained by withdrawing the rigid wire within the hypo-tubes500. Expansion of the pre-formed nitinol hypo-tube500 can be performed manually (slide action) or through a self-expanding configuration.
• An eighteenth exemplary embodiment of the proximal end apposition improvement device is illustrated inFIGS. 170 to 172. In this embodiment, thetip632′″ has been givenexpandable exterior segments6322′, in this case, three segments. Thetip632′″ also contains an interior expansion mechanism, for example, a spring actuated or pusher actuated mechanism, that extends theexterior segments6322′ from the position shown inFIGS. 170 and 171 to the position shown inFIG. 172. When thetip632′″ is so expanded, it becomes centered within the curved vessel, thereby also centering theproximal end12 of thestent graft1100.
• The tip-centering embodiments are not limited to the distal end of thedelivery assembly600. Theguidewire610 can also be utilized. More specifically, in a nineteenth exemplary embodiment of the proximal end apposition improvement device, theguidewire610 can be provided with an expanding “basket”520 at the distal end thereof as shown inFIGS. 173 to 175. This basket520 can be either self-expanding or manually expanded and opens within the aorta when the basket520 is just upstream of theimplant plane400. Thedelivery assembly600 is, then, introduced over theguidewire610 to the deployment site. After delivery of thestent graft1100, theguidewire610 is withdrawn into theguidewire lumen620 of thedelivery assembly600 and withdrawn along with theassembly600.
• A twentieth exemplary embodiment of the proximal end apposition improvement device is illustrated inFIG. 176. This embodiment provides an alternative to the bio-absorbablebare stent30 by including a removablebare stent30′. Utilizing such abare stent30′ during deployment but removing it after apposition of theinflow plane300 and theimplant plane400 is confirmed provides the self-centering features of the originalbare stent30 but without the detrimental affects that can be caused by the long-term exposure of thebare stent30 to the interior wall of the vessel in which thestent graft1100 is implanted. This removablebare stent30′ can be fixed onto or be a part of theapex capture device634. Thebare stent30′ can be fixedly secured to the proximal end of thedistal apex head636, for example, and removably secured to theproximal end12 of thestent graft1100. Detachment of thebare stent30′ can be accomplished in a variety of ways. One exemplary embodiment can collapse thebare stent30′ with a collection ring that slides over thebare stent30′ in a proximal direction. As the ring progresses proximally along the individual turns of thebare stent30′, a radially inward force is imparted to eachproximal apex32′ sufficient to release or break the contact between the apex32′ and thestent graft1100. Another exemplary bare stent removal device reverses the orientation of a hook that connects each apex32′ to thestent graft1100 so that theapex capture device634 is moved distally to release thebare stent30′ from thestent graft1100.
• It is envisioned that any of the nineteen exemplary embodiments described above can be used individually or in any combination.
• While exemplary embodiments of the invention have been illustrated and described, it will be clear that the invention is not so limited. Numerous modifications, changes, variations, substitutions, and equivalents will occur to those skilled in the art without departing from the spirit and scope of the present invention as defined by the appended claims.

Claims (1)

What is claimed is:

1. A method for implanting a prosthesis centrally within a curved lumen, which comprises:

loading a prosthesis into a delivery sheath, the prosthesis having a proximal end and the sheath having a distal end;

advancing the sheath in a patient towards the curved lumen to place at least the proximal end within the curved lumen; and

substantially aligning an inflow plane, which is defined by the proximal end of the prosthesis to be implanted in a patient, with an implant plane, which is defined by a ring of tissue inside a vessel at which the proximal end of the prosthesis is to be implanted, in a common plane that is transverse to a major longitudinal axis of the vessel.

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