Patent ID: 12220306

DETAILED DESCRIPTION

Reference now will be made to details of exemplary embodiments according to the invention. It is to be understood that the described embodiments are not intended to limit the invention solely and specifically to only these embodiments.

Methods and apparatus for stabilizing and treating an aneurysm include deploying a modular, sectional exclusion device, such as a stent graft, in the flow lumen of a blood vessel to span the aneurysmal location and seal off the aneurysmal location of the blood vessel from further blood flow while acting as a conduit to direct blood flow past the aneurysmal site. In the case of an aneurysm near a branch artery, methods and apparatus for treatment include positioning a modular endovascular stent graft in the aneurysmal site, where the stent graft includes a main body with at least one aperture, and in some embodiments two or three or more apertures, where separate individual inserts are disposed within each aperture to extend sealingly into the exclusion device and sealingly into a branch artery. A polymeric compound is used on either the insert, within the aperture or both, to ensure a snug, well-sealed fit between the aperture in the main body and the insert.

In addition to versatility in accommodating branch vessels, modular stents allow for in situ adjustment of insert lengths to accommodate different patient needs. Modular stent grafts are known in the art, and are disclosed in, inter alia, U.S. Pat. No. 6,129,756 to Kugler, et al.; U.S. Pat. No. 5,824,040 to Cox, et al.; U.S. Pat. No. 6,093,203 to Uflacker, et al.; U.S. Pat. No. 6,579,312 to Wilson, et al.; U.S. Pat. No. 5,906,641 to Thompson, et al.; and U.S. Pat. No. 5,855,598 to Pinchuk, et al., all of which are incorporated by reference in their entireties in for all purposes.

Each of the apertures of the main body of the stent graft is alignable with, and extendable into, a branch artery to aid in maintaining alignment of the aperture with the branch artery for providing additional positional stability for the deployed stent graft. The stent graft excludes the weakened vessel wall at the aneurysmal site from further exposure to blood flowing through the aorta, but, as a result of the aperture, allows blood to flow from the aorta to the branch artery(ies), even where the main body of the stent graft extends across the branch artery(ies). Inserts are then provided to fit sealingly into each aperture and further extend sealingly into the branch vessels, thereby preventing leakage of blood from the branch arteries into the region between the stent graft and the weakened blood vessel wall at the aneurysmal location. A polymeric compound strengthens the seal between the main body of the stent graft and the insert.

Referring initially toFIG.1, there is shown an aneurysm of the abdominal aorta10, such that the aorta is enlarged at an aneurysmal location14wherein the aorta wall12is distended and stretched. The aneurysmal location14forms an aneurysmal bulge or sac18. If left untreated, the aneurysmal portion of the aorta wall12may continue to deteriorate, weaken, and eventually tear or burst. The aorta10extends upwardly from the heart (not shown), such that at the aortic arch50, three branching arteries, the brachiocephalic trunk56, the left common carotid artery54and the left subclavian artery52, extend from aorta10.

FIG.2Ais an exterior side view of a modular stent graft that may be used to treat the aneurysm inFIG.1and that incorporates, as will be described further herein, a polymeric compound in one embodiment according to the present invention. There is shown generally a main body of the stent graft20comprising a tubular stent frame (framework)22and a graft material24attached to the stent frame22such as by sewing the graft material24to the stent frame22, which together form an integral tubular structure having a profile substantially mimicking that of a healthy thoracic aorta. In one aspect, the stent frame22may be formed of a plurality of wires, each of the wires bent into a zig-zag configuration and joined at its opposed ends to form a continuous hoop. The individual wires are then interconnected by a plurality of spanning wires, which are crimped at their opposed ends which are crimped to adjacent formed wires to form the support structure of the stent frame22. This support structure is attached to the graft material24, such as by sewing the two portions together, and then positioned in the aorta to push against the aorta wall12and support the graft material24so as to enable the graft material24to seal against healthy portions of the aorta wall12and to provide a conduit through which blood flows and bypasses the aneurysmal location14of the aorta10.

In the stent graft shown inFIG.2A, there are three apertures (generically at60) extending from the main body21of the stent graft20, specifically apertures62,64and66, extending from the wall of the main body of the stent graft20. Referring back toFIG.1, when the stent graft24is deployed in the aorta10, aperture66accommodates the exit of the brachiocephalic trunk56from the aortic arch50, aperture64accommodates the exit of the left common carotid artery54from the aortic arch50and aperture62accommodates the exit of the left subclavian artery52from the aortic arch50. In addition to the brachiocephalic trunk, the carotid artery and the left subclavian artery, other branched vessels (not shown) may be present and would be accommodated by one or more apertures as appropriate.

FIG.2Aalso shows three inserts72,74and76, having both stent frame22′ and graft24′ components, i.e., each of the inserts72,74and76are configured with a stent frame sized to be slightly larger than the circumference of the branch artery into which it is inserted, and has a tubular length of graft24′ material sewn or otherwise affixed thereto. Insert76is configured to be inserted into aperture66which accommodates the exit of the brachiocephalic trunk56from the aortic arch50and which supports the vasculature thereof; insert74is configured to be inserted into aperture64which accommodates the exit of the left common carotid artery54from the aortic arch50and which supports the vasculature thereof; and insert72is configured to be inserted into aperture62which accommodates the exit of the left subclavian artery52from the aortic arch50and which supports the vasculature thereof.

The materials making up the stent frame portion of the stent graft and/or insert(s) may be a metal, such as stainless steel, nitinol (NiTi) or tantalum (Ta), all known well in the art. In addition, various iron alloys such as iron platinum, iron palladium, iron nickel cobalt titanium, iron nickel carbon, iron manganese silicon, and iron manganese silicon chromium nickel. Generally the diameter of the metal wire/tube used for construction of the stent is between about 0.005 inches to about 0.02 inches. When nitinol is employed, the stent graft may have shape memory characteristics. While a braided construction of the stent frame is shown, this depiction is merely representative of any one of the numerous stent frame structures used to support stent grafts as is well known by persons skilled in the art.

The material composing the graft24of the stent graft20may be any biocompatible material that is mechanically stable in vivo, and is capable of preventing or substantially reducing the possibility of the passage or flow of blood or other body fluids there through. Typical materials for graft24include biocompatible plastics such as implantable quality woven polyester. Such polyester material may also include, therewith, components such as collagen, albumin, of an absorbable polymonomer or of a biocompatible fiber. Additionally, non-resorbable elastomers or polymers such as silicone, SBR, EPDM, butyl, polyisoprene, Nitril, Neoprene, nylon alloys and blends, poly(ethylene-vinyl-acetate) (EVA) copolymers, silicone rubber, polyamides (nylon 6,6), polyurethane, poly(ester urethanes), poly(ether urethanes), poly(ester-urea), polypropylene, polyethylene, polycarbonate, polytetrafluoroethelene, expanded polytetrafluoroethelene, polyethylene teraphthalate (Dacron) polypropylene and polyethylene copolymers.

In the embodiments shown herein, where the stent graft20further includes apertures such as apertures62,64and66which align with branch arteries adjacent to the aneurysmal site14, and also receives an insert such as insert72,74and76in each of the apertures, the inserts, and optionally the region of the apertures62,64and66into which the inserts are received, may be formed of or coated with a non-resorbable polymer such as polymethylsiloxane, polydimethylsiloxane or polymethylphenylsiloxane or silicone. For example, each of the inserts72,74and76may comprise a stent graft type structure, onto which a non-resorbable polymer, including polyurethane, silicone, polymethylsiloxane, polydimethylsiloxane or polymethylphenylsiloxane are coated thereon. The coating can be accomplished by sewing or adhering strips of the polymer to the mating surfaces of the inserts and apertures, by spray coating, by dip coating or vapor coating the materials thereon. Additionally, the inserts, and/or the apertures may be formed of a compound material formed, such as, for example, by insert molding wherein the aperture (62,64or66) portions of the stent graft20are held in a mold and a polymer such as silicone is molded thereto. Where the stent frame22portion of the stent graft20is composed of a shape memory material, the material(s) selected to coat the apertures must also be able to withstand, without degradation of its mechanical properties which would render it incapable of sealing against itself, temperatures sufficiently low, on the order of the temperature of liquid nitrogen, to allow the tubular stent graft to be compressed into a small diameter structure for insertion into a delivery catheter as will be further described herein.

In one aspect, the non-resorbable polymer may be silicon, which is dip coated or insert molded to appropriate portions where the stent graft20and inserts72,74and76engage one another in intended sealing contact. The silicone may be, for example, simply adhered to the stent graft20inner surfaces about the inner perimeter of the apertures60, such as by lowering or placing the apertures60over a mandrel or rod having an as yet uncured, substantially viscous silicon located thereon. This could be performed, for example, by dipping the rod into a bath of uncured silicone, such that a film of silicone forms thereon, and mating the rod to the interior of the apertures. Likewise, the rod could be rolled over the exterior surface of the portion of the inserts72,74and76which are to be received in the apertures, and thus the silicone will become adhered to, and thus deployed on, the surface of the inserts72,74and76. The silicone is then allowed to cure, either in air at atmospheric temperature and pressure conditions, or in an oven at elevated temperature.

The stent graft20and inserts72,74and76ofFIG.2Ashow two different paradigms for use of the polymer on the components for sealing of the inserts72,74and76to the apertures60. Insert76and aperture66are coated with the polymer entirely about the circumferential mating or contacting position of the insert76to the aperture66. In this case, the coating65extends entirely about the circumference of the insert76and from the end thereof which is received in the aperture66by a distance equal to the length by which the insert76is received in the aperture66. Likewise, coating65′ is received in aperture66substantially about its entire projected length. In contrast, apertures62and64, and likewise inserts72and74, demonstrate a different aspect, in which a continuous circumferential coating of the polymer is replaced by a series of longitudinal stripes67extending along the outer surface of the inserts72,74and stripes67′ of the polymer extend longitudinally along the inner surface of the apertures (aperture projection or nozzles)62,64into which the inserts72,74are received. In this aspect, the polymer stripes reduce the bulk of material and the circumferential stiffness of the stent graft, by leaving open spaces of bare graft material between the longitudinal stripes67. Thus, in one example, such a configuration provides an alternate back and forth folding pattern as the stent graft diameter is reduced to its compressed state for delivery within the delivery system. In such a pattern when folded (compressed), the longitudinal stripes are not in contact with any adjacent longitudinal stripes, but only with the bare graft or stent frame materials, so that premature melding of polymer stripes to one another does not occur to cause sticking between adjacent folds when the stent graft is deployed (expanded). In this aspect, the inserts72,74, when received in their respective apertures62,64, are configured and positioned such that a portion of the stripes on the inserts72,74contacts a portion of the stripe on the aperture.

The thickness of the graft material optionally is minimized to reduce the overall cross sectional thickness of the stent graft20and thus the size of the stent graft20as deployed in a delivery catheter. Generally, the graft material will be thinner than about 0.005 inch, and may be thinner than about 0.002 inch.

In the embodiment of the stent graft20shown inFIG.2A, the ends of the graft material24extend beyond the marginal edges of the stent frame22, i.e., the graft material24extends axially beyond the opposed generally circular ends of the stent frame22to form opposed ends26,28of the stent graft20. This arrangement is one of various arrangements of the position of the graft20portion with respect to the stent22, as in other embodiments according to the present invention the ends of the graft portion24are coincident with the opposed ends of the stent frame22or the ends of the stent frame22may extend beyond the marginal ends of the graft portion24. The ends of the graft portion24of the stent graft20are preferably configured to prevent fraying, which may be accomplished by heat fusion or binding of the edge of the graft portion24or by folding the end of the graft portion24back upon itself and sewing it to the stent frame22or to itself. Also, the graft portion24may be located on the interior of the stent frame22, on the exterior of the stent frame22, or the graft portion24may be located in the interstitial spaces between the portions or sections of the stent framework (shown as a braided pattern in the Figures herein). The graft portion24may include more than one layer or ply. The graft24preferably is sufficiently non-porous to prevent blood from leaking into the aneurysmal sac18(FIG.1). In some embodiments, the material forming the graft portion24may include a coating of non-porous material over one or more porous layers. The graft portion24is attached the stent frame22, typically as by sewing the graft24to the stent frame22, but the use of an adhesive, heat bonding of the graft24to the stent frame22, or other methodologies are specifically considered acceptable so long as the integrity of the connection of the graft24to the stent frame22is maintained.

FIG.2Bis a close up of one example aperture66′ of the type shown in the group of apertures60formed on the main body21of the stent graft20, and an example of an insert76′ of the plurality of inserts72,74and76fromFIG.2A. In this embodiment, the inserts such as insert76shown inFIG.2Aare not coated with a polymer or other sealing and securing material, but instead a ring82of the sealing or securing material such as silicone is sewn or otherwise attached to the insert, and likewise a ring82′ of the sealing or securing material is secured within the inner circumference of the aperture66′ into which insert76′ is to be deployed. As shown inFIG.2B, the aperture66′ (as well as similar adjacent apertures (not shown) like apertures62,64) preferably have a neck portion80which extends outwardly, in a tubular cross section, from the main body21′ of the stent graft20′, and includes a ring82′ formed thereon in the manner previously discussed. The insert76′ (and likewise adjacent inserts) is secured within the aperture66′ by friction between the conformable mating polymeric surfaces. In addition, where the material of the rings82,82′ is a polymer having a low glass transition temperature, the area of contact between two adjacent rings82,82′ will fuse together over time in situ (as it will in the other examples where polymer to polymer contact is described). Additionally, a portion of the insert76extends outwardly from the main body21′ of the stent graft beyond the end of the neck portion80of the aperture66′ and is positioned against the wall of the branch vessel into which it is deployed, preventing leakage of blood or other fluids past the apertures (e.g.,62,64and66) of the stent graft20, while allowing blood to flow through the inner tubular portion of both the apertures (e.g.,62,64and66) and the inserts (e.g.,72,74and76).

To deploy the stent graft20endovascularly, the stent graft20must be configured to fit within a tubular catheter. To accomplish this, the main body21of the stent graft20is first compressed, as shown inFIG.2C, and then further folded or compressed to the configuration (diameter) ofFIG.2Dat which time it may be inserted into the end of a catheter such as catheter30shown inFIG.3. During the compressing of the stent graft20, a guide wire catheter33may first be extended therethrough, as is also shown inFIG.2C. The guidewire catheter33is a hollow tube through which a guidewire31(FIG.3) is passed, and supports, at its distal end thereof, an insertion end32(catheter tip) through which guidewire31likewise extends (FIG.3). For deployment of the stent graft20, the guidewire catheter33extends within the length of the tubular catheter30such that its distal end is attached to the insertion end32and its proximal end is manipulable by a technician or surgeon to position the distal end in relative proximity of the deployment location. Where the stent frame22portion of the main body21of the stent graft20is configured of a shape memory material, such as nitinol, the main body21can be first cooled to a very low temperature, such as by using sprayed bursts of liquid nitrogen which depending on the composition of the nitinol can make the nitinol plastically deformable an easier to load, before it is compressed (as shown inFIGS.2C and2D.) Where the stent portion22is comprised of a non-shape memory material, an inflation device such as a balloon34on the guidewire catheter33connected to an end of an inflation lumen38extending along the guidewire catheter33is first located inside of the tubular shape of the main body21, onto which the stent graft can be compressed. Likewise, inserts72,74and76can be compressed and placed in separate catheters, one such catheter shown as catheter30′ inFIG.3A. Each insert may be located in a single catheter, or all of the inserts necessary to deploy one into each of the apertures60may be deployed in a single catheter, with one insert closest to the open end thereof, and the next one(s) stacked therebehind. Additionally, where the inserts are configured incorporating a non-shape memory alloy as the stent material, a balloon must be first placed inside the tubular volume before compressing it. This can be unnecessary where the insert is self expanding. It is also possible that the insert is compressed over the smaller balloon and is able to adhere to the balloon without the use of an outer sheath.

Referring still toFIG.3, the initial deployment of the stent graft20into the thoracic arch into an aneurysmal location14spanning position is shown. Prior to the deployment of the stent graft20, a guide wire31is extended from a remote blood vessel incision site leading to the arch50, and through the arch50, such that the inserted end thereof extends past the intended location of the deployed stent graft20. To position and properly locate the stent graft20in a spanning, sealed position in the aneurysmal location14, the stent graft20is introduced through an artery, such as the femoral artery (not shown), by inserting the catheter30into the artery through an incision in the leg. The catheter30preferably includes an outer sheath portion enclosing a collapsed or compressed stent graft20held within a distal end of the sheath30which is introduced into the patient's artery and from which the stent graft20is deployed. A proximal end of the catheter (not shown) is maintained external to the body and is manipulated to axially and rotationally position catheter within the aorta10. At least one push rod36can extend within the catheter30, from a position adjacent to the distal end of the stent graft20within the hollow portion of the catheter30, to a position beyond the proximal end of the catheter30. Additionally, where a balloon is employed in the deployment of the catheter, a lumen38capable of introducing saline extends from a balloon34within the stent graft20to a position beyond the proximal end of the catheter30where it is connectable to an inflation device. Catheter30and any other catheters required for deployment typically carry radiological markers on their outer surface adjacent the deployment end38, to enable the surgeon deploying the stent graft to determine the position of the catheter in the body, such as by fluoroscopic or other means. Additionally, the stent graft20has radiological markers thereon to enable determination of the position and rotational orientation thereof at the aneurysmal location.

In deploying the stent graft20, catheter30is tracked through the patients' artery, until the end thereof is disposed in the arch physically beyond the aneurysm location14. The push rod36which is located against the distal end of the stent graft20within catheter30, and holds the stent graft20stationary as the tubular sheath of the catheter30, is withdrawn or retracted with respect to the aneurysmal location14. As the sheath retracts, the stent graft20is progressively released from the sheath in a position spanning across the aneurysmal location14of the aorta. As the catheter sheath is withdrawn with the push rod36held stationary, and as the deployment of the stent graft20is beginning, the catheter30may be rotated to ensure that the main body21of the stent graft20deploys with the apertures62,64and66in alignment with the branch arteries52,54and56.

The stent graft apertures62,64, and66are, when the stent graft20is properly aligned in the aorta10and arch50, aligned with the branch arteries52,54and56, and expanded to extend outwardly from the wall of the stent graft20. In the configuration of the embodiment of the stent graft inFIGS.2A and3, three branch arteries must be spanned and thus three apertures60are provided. Alternatively, where the size and location of the aneurysmal sac18enables a shorter length of stent graft to ensure sufficient sealing of the stent graft against the wall of the aorta, or, where the aneurysmal sac is more remotely located from the branch artery locations, the stent graft may be deployed with fewer openings therein, and an aperture60need only be located in each of those openings. After the main body21of the stent graft20is deployed, the balloon, where used, is deflated and withdrawn along with the catheter30.

A separate catheter, e.g.,30′, may be used to deploy each insert72,74and76into each separate aperture62,64and66. This is provided by deploying additional catheters in a number equal to the number of inserts used, through the artery and within the stent graft20, and extending each catheter along a guidewire into individual stent graft branches60. To direct the catheters into the appropriate apertures60, a guide wire31′ is first deployed and guided into and past the appropriate aperture and a further distance along the appropriate branch artery52,54or56. The catheter is positioned such that the distal end of the catheter is disposed inside of the aperture and branch vessel where the insert in the branch vessel will be located. As with the deployment of the main body21, the sheath of the catheter30′, with a push rod (not shown) positioned against an insert72,74or76, is withdrawn and the insert72,74or76deploys, with the shape memory material expanding to the expanded diameter of the tubular section of the insert72,74or76, with the outer surface thereof engaged with the inner surface of the aperture to sealingly secure the insert72,74or76therein by an interference or friction fit, with the portion extending outwardly therefrom in sealing engagement with the adjacent wall of the particular branch vessel50into which it is deployed. Where shape memory material is not used, a balloon is positioned within the insert72,74or76, to cause its expansion. This procedure is repeated, with repositioning of the guidewire and redeployment of the catheter30′, until all of the needed inserts are deployed. Once the stent graft main body21and inserts72,74and76are deployed, all balloons (where needed) are deflated, the catheters and guidewires are withdrawn, and the artery and leg incision(s) are closed. The stent graft20and inserts72,74and76are thus positioned, spanning the branch arteries without blocking them. Methods and apparatus for the deployment of sectional stent grafts are also disclosed in U.S. Pat. No. 5,683,451 to Lenker, et al.; U.S. Pat. No. 5,713,917 to Leonhardt, et al.; and U.S. Pat. No. 5,984,955 to Wisselink, et al., all of which are incorporated by reference in their entireties in for all purposes.

Once the inserts72,74and76are positioned in the respective apertures62,64and66, the contacting surfaces of the polymer disposed on both the apertures62,64and66and the inserts72,74and76provide both sealing of the insert-aperture interface, but likewise provide increased friction due to the polymer to prevent the movement of the inserts with respect to the apertures. Over time, the interface of the (polymer) sealing materials may meld together to form a continuous adhering material between the insert and the aperture. However, the ability of these materials to meld together is, in part, based upon their tackiness, i.e., the ability or desire of the material to stick to materials into which it comes in contact. This property may affect the ability to deploy the apertures62,64and66and the inserts72,74and76, as the sealing and securing material thereon, for example the coating65or65′, may come into contact with itself during the compressing of the stent graft20or the inserts72,74and76for the placement thereof into catheters. To minimize the risk that the apertures of the stent graft20or the inserts72,74and76will become adhered together in the collapsed state, three construction and/or deployment paradigms may be used: Firstly, a balloon may be provided within the envelope of each of the apertures62,64and66and inserts72,74and76, such that the inflation thereof, in situ, will overcome any sticking of the material65to itself. Secondly, the sealing and securing material may be comprised as stripes67,67′, as shown inFIG.2A, such that upon compressing of the stent graft20or the inserts72,74and76, the stripes67,67′ of sealing and securing material contact stent22or graft24material, and not an adjacent stripe67,67′. Thirdly, the coating65,65′ may, prior to the compressing and configuring of the stent graft20and the inserts72,74and76, be covered with a release, material, such as a thin sheet of PTFE or FEP material, which material is adhered likewise to a wire or other catheter deployable member which can be pulled outwardly of the patient, during the deployment of the stent graft20or inserts72,74and76, to pull the sheet off of the polymer prior to the contact of the polymer carrying portion of the insert72,74or76with its appropriate aperture62,64or66. Thus, the stickiness or tackiness of the polymer may be used to help secure and seal or meld the insert and aperture together, while the inserts72,74and76and apertures62,64and66are expandable in situ.

Referring toFIG.4, once deployed, the stent graft20is intended to provide a flow conduit across the aneurysmal sac18of the aorta10, and to seal off the aneurysmal sac18from further blood flow. The stent graft20is sized so that, upon deployment in the aorta10, the diameter of the stent graft20is slightly larger than the normal, healthy diameter of the aorta10so that the opposed ends26,28of the stent graft20are in apposition with the inner wall of the aorta10. Further, the stent graft20is long enough to span the aneurysmal sac18of the aorta10and sealingly contact the aorta wall12on opposite sides of the aneurysmal sac18. Such sealing includes the region of the aorta wall12between the branch arteries52,54and56, as well as regions distal and proximal from the aneurysmal region18. To enable sealing by the stent graft20, the stent graft includes a circumferential wall, which, at opposed ends26and28, is engageable against the inner wall12of the aorta10to effect sealing and prevent, when properly deployed, blood flow into the aneurysmal sac18of the aorta10. Additionally, the inserts72,74and76extend into the branch arteries52,54and56, providing an extended conduit for blood flow thereby excluding blood from the region of the branch vessels where vessel delamination (dissection) may occur.

WhereFIG.1shows an aneurysm near the thoracic aortic arch,FIG.5is an artist's rendering of an aorta showing an aneurysm in the abdominal aorta.FIG.5shows an aorta110with an aortic wall at112. There is an aneurysmal site at114, defining an aneurysmal sac at118. Renal arteries are seen at116, the right iliac artery is seen at119and the left iliac artery is seen at117.

FIGS.6A and6Bare schematic exterior side views of a stent graft useful for excluding an aneurysm of the aorta shown inFIG.5.FIG.6Ashows a main body of the stent graft120generally, with a stent frame122and graft portion124. In addition, stent graft120has a second branch insertion site125, as well as a polymeric compound182such as a polymeric compound such as that used in conjunction with the inserts and apertures of the embodiment shown inFIGS.2,3and4disposed inside the insertion site (shown in phantom). Also inFIG.6A, there is an insert170having an insertion end171, likewise comprised of a stent frame portion122and graft portion124. On insert170, there is disposed, at180, a polymeric compound such as that used in conjunction with the inserts and apertures of the embodiment shown inFIGS.2,3and4.

FIG.6Bshows the main body of the stent graft120and insert170ofFIG.6Aassembled. InFIG.6B, insertion end171of insert170is disposed within the main body of the stent graft120, such that the polymeric compounds180,182on the insert170and the main body of the stent graft120engage against one another.

FIG.6Cshows the assembled stent graft and insert fromFIG.6Bpositioned within an abdominal aortal region ofFIG.6A. The aorta110shows an aorta wall at112, an aneurysmal region at114and an aneurysmal sac at118. The renal arteries are seen at116, the left iliac artery is seen at117and the right iliac artery is seen at119. Stent graft120and insert170are shown with stent portions122and graft portions124. The insertion end of insert170is shown at171. The stent graft120and insert170are deployed similar to how stent graft20shown inFIGS.2,3and4is deployed, i.e., the main body stent graft120is tracked, in a catheter, up the right iliac artery119, and deployed from the catheter and positioned as shown inFIG.6C. The insert170, which forms the contralateral leg of the assembled stent graft, is tracked in a catheter up the left iliac artery117, such that the end thereof having the polymeric compound180thereof is inserted into the opening125of the stent graft120, and then inflated or otherwise restored to its free state such that polymer portions180and182contact one another.

FIG.7Ais an exterior side view of an upper portion of an example of a custom configured stent graft useful for excluding an aneurysm of an aorta as shown inFIG.5.FIG.7Ashows a main body of a stent graft120′ generally, with stent frame/support portions122′ and graft portions124′. In addition, stent graft120′ has branch insertion sites125aand125bthat extend radially outwardly from the stent graft120′ and which align with the renal arteries (not shown) when the stent graft120′ is deployed. Polymeric compound182, such as the polymeric compound used in conjunction with the inserts and apertures of the embodiment shown inFIGS.2,3and4, is disposed inside the insertion sites125aand125b. Also shown inFIG.7A, are inserts170aand170bhaving mating ends171aand171b, on which is disposed the polymeric compound at180. The embodiment of the stent graft120′ ofFIG.7Afurther includes two fenestration extensions at127a,127bwith the polymeric compound184disposed on the outer surface thereof. The fenestration extensions accommodate the celiac trunk and the superior mesenteric artery (not shown) when the stent graft120′ is deployed.

FIG.7Bshows the upper portion of the stent graft120′ fromFIG.7Aassembled with two additional portions positioned within an abdominal aortal region. The aorta110has an aorta wall at112, an aneurysmal region at114and an aneurysmal sac at118. Renal arteries are seen at116, the left iliac artery is seen at117and the right iliac artery is seen at119. The stent graft120′ consists of five portions: an upper portion121along with inserts170aand170bseen inFIG.7B, as well as inserts170cattached to the open lower end of upper portion121and including a leg which accommodates right iliac artery119, and an insert170dwhich forms a leg and extends from an opening in the insert170cinto sealing engagement with the left iliac artery117. Inserts170a,170b,170cand170deach have insertion ends171a,171b,171cand171d, respectively, with the polymeric compound disposed thereon.

In addition,FIG.7Bshows fenestration extensions127a,127bfromFIG.7A. Fenestration extension127aaccommodates the superior mesentery artery (not shown), and fenestration extension127baccommodates the celiac trunk (not shown). Polymeric compound184aand184bis disposed on the outer surface of the fenestration extension to provide enhanced sealing of the fenestration extension with the branch arteries.

FIGS.8A and8Bare exterior side views of yet another configuration of stent graft useful for excluding the abdominal aorta shown inFIG.5.FIG.8Ashows a main body120″ of a stent graft and an insert170″. Again, both the main body120″ of the stent graft and insert170″ have stent portions at122″ and graft portions at124″. The main body120shows an insertion site125for insert170″ as well as polymeric compound182″, a polymeric compound such as that used in conjunction with the inserts and apertures of the embodiment shown inFIGS.2,3and4, disposed within the inside rim of the insertion site. Insert170″ shows an insertion end at171″ as well as the polymeric compound at180″ shown applied around the insertion end.FIG.8Bshows the main body120″ of the stent graft and the insert170″ ofFIG.8Aassembled. Again, stent frame122″ and graft124″ portions are seen on both the main body120″ of the stent graft and the insert170″. In addition, a portion of the insert170″ is shown in phantom178″ disposed within the stent graft120. Polymeric compounds180and182are seen in phantom as well.

FIG.8Cshows the assembled stent graft/insert combination ofFIG.8Bpositioned within an abdominal aneurysm. Again, an aorta is seen at110, an aortal wall is seen at112, an aneurysmal region is seen at118and an aneurysmal sac is seen at118. Renal arteries are shown at116, the left iliac artery is shown at117and the right iliac artery is shown at119. Main body120″ of stent graft and insert170″ are also shown.

FIG.9is an exterior side view of yet another stent graft useful for excluding the aneurysm of the abdominal aorta shown inFIG.5.FIG.9shows a four-piece modular stent graft, with a main body at120″ and inserts at170a′″,170b′″ and170c′″. Stent122′″ and graft124′″ portions are shown on each of the four modular pieces. Insertion end171a′″ of insert170a′″ is shown, as is insertion end171b″ of insert170b′″ and insertion end171c″ of insert170c′″. Polymeric compound, a polymeric compound such as that used in conjunction with the inserts and apertures of the embodiment shown inFIGS.2,3and4, is shown disposed on the inserts at180a′″,180b′″ and180c′″. In addition, polymeric compound such as silicone is shown disposed within stent graft main body120′″ in phantom at182a′″,182b′″ and182c′″.

FIG.10is an artist's rendering of a blood vessel showing an aneurysm adjacent a branch portion of the vessel.FIG.10shows an aorta at210, having aortal branches at211. The aortal wall is seen at212, the aneurysmal site is seen at214and the aneurysmal sac is seen at218.

FIG.11Ais an exterior side view of two parts of a rotation cuff device useful for excluding the aneurysm of the vessel shown inFIG.10. An outer cuff290has a polymeric compound (such as that used in conjunction with the inserts and apertures of the embodiment shown inFIGS.2,3and4) on various portion of the inner surface. Polymer coating is applied to at least one of the several areas shown. Generally there is continuous uninterrupted layer covering the coating area, though a striped coating configuration (as discussed above) can also be used. The coating area extends from the edge of the circular aperture (branch) or rectangular aperture outwardly from the opening and provides at least a minimum width contact area for the polymeric compound. While polymeric coatings are here shown on both pieces (outside of the inner one and on the inside of the outer one around both sets of openings), the polymeric coating can be configured with less initially coated area, such that the parts are configured to have a polymer coating in the space between layers around each branch related opening, when assembled. In this embodiment, edges of the polymer covered areas (coatings) on the inside surface are shown by dashed lines on the outer cuff290at opening294. Opening294accommodates the inner cuff aperture273. The insert cuff270, having an insert aperture at273and the insert aperture284both have a polymeric compound area280disposed around their edge as shown by the cross hatched area. While rectangular shaped areas for the polymer are shown, other geometric shapes which provide an edge sealing zone or continuous seal completely around the opening can be used. Opening284accommodates the outer cuff aperture293.

FIG.11Bis an exterior side view showing the two parts290,270of the rotation cuff ofFIG.11Aassembled. A portion of the inner cuff270is seen through opening294. The outer cuff aperture is seen at293and the inner cuff aperture is seen at273. Areas having polymeric compound coatings are shown in dashed and cross hatched lines,293′ and273′ around outer cuff aperture293and inner cuff aperture273.

FIG.11Cis an exterior side of the assembled cuff ofFIG.11Bpositioned in the branched vessel region shown inFIG.10. The aorta is seen at210, the aortal wall is seen at212, the aneurysmal region is shown at214and the aneurysmal sac is shown at218. Branched arteries are seen at216. The assembled cuff device is seen at300, with outer cuff aperture293and inner cuff aperture273shown.

The stent grafts and cuffs according to the present invention may, optionally, deliver a therapeutic agent by way of a coating on the stent and/or graft material. In such an embodiment, the coating compound is adapted to exhibit a combination of physical characteristics such as biocompatibility, and, in some embodiments, biodegradability and bio-absorbability, while serving as a delivery vehicle for release of one or more therapeutic agents that aid in the treatment of aneurysmal or atherosclerotic tissue.

In selecting an appropriate therapeutic agent or agents, one objective is to protect the aneurysmal blood vessel from further destruction. Another objective is to promote healing. Generally, aneurysm results from the invasion of the cell wall by inflammatory agents that cause the release of elastin and collagen attacking proteins that for unknown reasons begin to congregate at certain blood vessel sites. Attack of the blood vessel structure causes further inflammation and cyclically the release of more of these elastin and collagen attacking proteins. Inflammation, the elastin and collagen attacking proteins, and the resulting breakdown of tissue, are leading causes of aneurysm formation.

Therapeutic agents useful in embodiments of the present invention include matrix metalloproteinase (MMP) inhibitors, which have been shown in some cases to reduce such elastin and collagen attacking proteins directly or in other cases indirectly by interfering with a precursor compound needed to synthesize the MMP's. Another class of agents, non-steroidal anti-inflammatory drugs (NSAIDs), has demonstrated anti-inflammatory qualities that reduce inflammation at the aneurysmal site, as well as an ability to block MMP-9 formation. Cyclooxygenase-2 or “COX-2” inhibitors also suppress MMP-9 formation. In addition, anti-adhesion molecules, such as anti-CD18 monoclonal antibody, limit the capability of leukocytes that may have taken up MMP-9 to attach to the blood vessel wall, thereby preventing MMP-9 from having the opportunity to attack the blood vessel extracellular matrix. Other therapeutic agents contemplated to be used to inhibit MMP-9 and possibly MMP-2 are tetracycline and related tetracycline-derivative compounds.

Steroidal anti-inflammatory drugs such as dexamethasone, beclomethasone and the like may be used to reduce inflammation. Another class of therapeutic agent that finds utility in inhibiting the progression of or inducing the regression of a pre-existing aneurysm is beta blockers or beta adrenergic blocking agents. In addition to therapeutic agents that inhibit elastases or reduce inflammation are agents that inhibit formation of angiotensin II, known as angiotensin converting enzyme (ACE) inhibitors. ACE inhibitors are known to alter vascular wall remodeling, and are used widely in the treatment of hypertension, congestive heart failure, and other cardiovascular disorders vascular wall injury.

The maximal dosage of the therapeutic to be administered is the highest dosage that effectively inhibits elastolytic, inflammatory or other aneurysmal activity, but does not cause undesirable or intolerable side effects. The dosage of the therapeutic agent or agents used will vary depending on properties of the stent, graft or coating material, including its time-release properties, whether the composition of the other components, and other properties. Also, the dosage of the therapeutic agent or agents used will vary depending on the potency, pathways of metabolism, extent of absorption, half-life and mechanisms of elimination of the therapeutic agent itself. In any event, the practitioner is guided by skill and knowledge in the field, and embodiments according to the present invention include without limitation dosages that are effective to achieve the described phenomena.

While the present invention has been described with reference to specific embodiments, it should be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the true spirit and scope of the invention. In addition, many modifications may be made to adapt a particular situation, material or process to the objective, spirit and scope of the present invention. All such modifications are intended to be within the scope of the invention.

All references cited herein are to aid in the understanding of the invention, and are incorporated in their entireties for all purposes.