Patent ID: 12213898

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

Turning to the drawings,FIGS.1-2Bshow an exemplary embodiment of a tubular graft10that includes an intermediate loop region20and a pair of self-sealing cannulation regions30on either side of the loop region20, e.g., configured to allow the tubular graft10to be punctured with a needle, cannula, and/or other device (not shown) to allow access into the graft10. In addition or alternatively, the cannulation regions30may provide access during other procedures, e.g., angioplasty, vascular stenting, or thrombectomy procedures, e.g., to manage and maintain AV patency for dialysis. In another alternative, the graft10may include only one cannulation region, if desired for a particular application, e.g., similar to the embodiments shown inFIGS.6C-6D,7A-7C, and8A-8C, and described further elsewhere herein.

Generally, the graft10includes an elongate tubular graft body12including first and second ends14a,14band a lumen16extending between the ends14a,14b, i.e., from the first end14aalong the first cannulation region30a, the loop region20, and the second cannulation region30bto the second end14b, thereby defining a central longitudinal axis18extending between the ends14a,14b. The graft body12may be fabricated from well-known synthetic or biological material for tubular grafts, e.g., a porous or nonporous material, such as ePTFE.

The graft10may be sized for implantation within a patient's body, e.g., within an arm of a patient (not shown) to provide an arteriovenous graft allowing arterial and venous access during hemodialysis. In exemplary embodiments, the lumen16may have an inner diameter between about one and forty millimeters (1-40 mm) or between about four and twenty millimeters (4.0-20 mm), and an overall length between the ends14a,14bbetween about five and eighty centimeters (5.0-80 cm).

As best seen inFIG.2A, the cannulation regions30may be substantially straight regions located adjacent the ends14a,14bthat include one or more reinforcement elements40embedded within a base material42and attached over or formed directly on desired lengths of the graft body12. Optionally, as shown inFIGS.1and2B, an outer layer of material, e.g., a sleeve of polymeric material, such as ePTFE, may be provided over the reinforcement elements40and base material42, e.g., between first and second ends32,34, of each cannulation region30, and/or a transition region36,38may be provided at each end32,34tapering to the underlying graft body12, e.g., to reduce the risk of the graft body12kinking immediately adjacent the cannulation regions30. In exemplary embodiments, each cannulation region30may be offset a desired distance from the respective end14, e.g., between about one and thirty centimeters (1.0-30 cm) or between about one and ten centimeters (1.0-10 cm), and may have a length between about one and twenty centimeters (1.0-20 cm) and a wall thickness between about 0.3 and five millimeters (0.3-5.0 mm).

In an exemplary embodiment, each cannulation region30generally includes a plurality of reinforcement elements, e.g., a plurality of zigzag elements40, e.g., formed from Nitinol or other elastic, superelastic, or shape memory material, embedded within or surrounding base material42, e.g., silicone or other elastomeric material. The base material42may be substantially non-porous, i.e., may prevent fluid flow through the wall of the cannulation region30, while, optionally, permitting tissue ingrowth, e.g., allowing surrounding tissue to grow into and/or otherwise engage the outer wall of the cannulation region30. The reinforcement elements40may extend circumferentially around the graft body12, e.g., as shown inFIG.2A, and/or axially along the graft body12(not shown) for the desired length of the cannulation region30, e.g., between the first and second ends32,34. For example, the reinforcement elements40may be biased to a relaxed or low energy state but elastically deformable to accommodate a needle or other device being inserted through the cannulation region30into the lumen16of the tubular graft10. Thus, when the device is removed, the reinforcement elements40may bias the base material42to return to its original orientation, thereby sealing any punctures through the cannulation region30. Exemplary embodiments of reinforcement elements, base material, and/or methods for making structures that may be used for the cannulation regions30may be found in U.S. Publication Nos. 2013/0237929 and 2016/0199085, the entire disclosures of which are expressly incorporated by reference herein.

For example, in the embodiment shown inFIG.2A, the reinforcement elements40may be annular bands formed from continuous rings or “C” shaped collars of Nitinol material, e.g., laser cut, mechanically cut, stamped, machined, and the like, from a tube, wire, or sheet, e.g., similar to embodiments described in the applications incorporated by reference herein. Each band may extend at least partially around the periphery of the graft body12transverse to the longitudinal axis18. For example, each band may include a plurality of longitudinal struts extending longitudinally including opposing ends that are alternately connected to adjacent struts by curved circumferential connectors, struts, or elements, e.g., to define an enclosed, annular zigzag or other serpentine pattern. The longitudinal struts may extend substantially parallel to the longitudinal axis18or, alternatively, may extend diagonally or helically relative to the longitudinal axis18(not shown).

Alternatively, the reinforcement elements40may include struts, wires, or other elements that extend axially along the length of the cannulation region30. For example, a plurality of substantially straight wires or other filaments (not shown) may be embedded within or otherwise fixed to the base material42. The filaments may be spaced apart sufficiently to accommodate inserting a needle or other device (not shown) through the cannulation region30, with the filaments moving laterally to accommodate the device passing therethrough and resiliently returning to their original configuration to substantially seal the cannulation region30, similar to other embodiments herein. Alternatively, the filaments may include a sinusoidal, zigzag, helical, or other pattern that extends at least partially transversely while the filaments extend generally axially between the ends32,34of the cannulation region30(also not shown), e.g., similar to other embodiments described elsewhere herein.

The material of the reinforcement elements40may be heat treated and/or otherwise processed to provide a desired finish and/or mechanical properties. For example, the bands shown inFIG.2Amay be heat treated such that the bands are biased to a desired relaxed diameter, e.g., slightly larger, substantially the same, or smaller than the outer diameter of the graft body12, yet the bands may be resiliently deformable, e.g., laterally within the circumferential plane of the cannulation region30to accommodate receiving a needle or other instrument (not shown) between adjacent struts and/or bands.

For example, in one option, the reinforcement elements40may impose a substantially continuous radially inward compressive force on the adjacent base material, i.e., radially inwardly towards the underlying graft body12, which may enhance sealing any passages created through the base material, similar to embodiments described in the applications incorporated by reference herein. To accomplish this, the reinforcement elements40may be shape set to define a diameter smaller than the outer diameter of the graft body12in a relaxed or low energy state, and the reinforcement elements40may be resiliently expanded to fit over the graft body12, e.g., before or after being embedded in the base material42. In another option, the reinforcement elements40may define a diameter larger than the outer diameter of the graft body12, e.g., such that the reinforcement elements40are in a low energy state radially that does not apply a radial force inwardly against the graft body12when embedded within the base material42.

Alternatively, the reinforcement elements40may impose a substantially continuous axial compressive force, e.g., similar to other embodiments described elsewhere herein, instead of or in addition to, a radially inward force. For example, the reinforcement elements40may be shape set to define a predetermined axial spacing between adjacent windings (e.g., zero or greater) in a relaxed or low energy state, and the reinforcement elements40may be resiliently axially stretched when positioned over the graft body12, e.g., before or after being embedded in the base material42, as described elsewhere herein.

Optionally, instead of the outer layer44shown inFIGS.1and2B, fabric (not shown) may be applied over any exposed surfaces, e.g., over the outer and end surfaces of the cannulation region30if the base material42is formed directly around the graft body12, e.g., with the reinforcement elements40embedded within the base material42at the same time. Alternatively, if the reinforcement elements40are embedded within the base material42before attachment to the graft body12, fabric may be applied over the outer, inner, and end surfaces before attachment. In another option, the cannulation regions30may include one or more tactile elements, ferromagnetic elements, echogenic elements, and the like (not shown), e.g., to facilitate locating the cannulation regions30when the graft10is implanted subcutaneously or otherwise within a patient's body, such as those disclosed in the applications incorporated by reference herein.

With particular reference toFIGS.2A and2B, the loop region20also includes one or more reinforcement elements22attached or otherwise provided around the tubular graft12along a first length of the loop region20. For example, as best seen inFIG.2B, the reinforcement element(s)22may extend circumferentially and/or axially along the loop region20entirely from one cannulation region30ato the other cannulation region30b. Alternatively, the reinforcement element(s)22may extend only partially between the cannulation regions30, e.g., along a first length corresponding to a bend of the loop region20.

The reinforcement element(s)22may be formed from a variety of materials that provide predetermined hoop strength and/or otherwise support the underlying graft body12to prevent the material of the graft body12from being crushed, kinking, or buckling when the loop region20is positioned in a curved orientation. For example, as shown inFIG.3, the loop region20may be bent or compressed into a tight loop, e.g., having a radius of curvature smaller than the diameter of the graft body12; the reinforcement element(s)22may be attached to or otherwise support the graft body12to keep the lumen16substantially open even in such a small radius curve.

In an exemplary embodiment, the reinforcement element(s)22may be formed from thermoplastic materials, e.g., nylon, PTFE, or FEP, shape set to define a desired curved or circumferential shape having a radius similar to the outer diameter of the graft body12. Alternatively, other materials may be used, e.g., Nitinol or other elastic or superelastic materials. The reinforcement element(s)22may have a desired cross-section, e.g., circular cross-section, an oval or elliptical cross-section, a square or rectangular cross-section, having a maximum width of between about 0.004-0.140 inch (0.1-3.5 mm), or not more than about 0.14 inch (3.5 mm).

The reinforcement element(s)22may be substantially permanently attached to the outer surface of the graft body12, e.g., by bonding with adhesive, such as a silicone adhesive, fusing, sonic welding, and the like. In addition or alternatively, an external sleeve or other layer of material (not shown) may be positioned around and secured to or around the reinforcement element(s)22, e.g., by interference fit, shrink fit, bonding, fusing, and the like. For example, in one embodiment, the reinforcement element(s)22may be applied around the graft body12without actually bonding to the graft body material (e.g., to create a pocket) and/or encapsulated around the graft body12to attach the reinforcement element(s)22to the underlying graft body12.

In an exemplary embodiment, the reinforcement element(s)22may include one or more sinusoidal or other zigzag members24,124including alternating loops (e.g., peaks24a,124aand valleys24b,124b) aligned along the longitudinal axis18of the first length. The zigzag member(s)24,124may define a simple sinusoidal shape, e.g., as shown inFIGS.4C and5C, or may define a more complicated configuration of peaks and valleys, as desired. The alternating loops24a,124a,24b,124bmay be shape set to extend at least partially around the circumference of the graft body12. Thus, the loops24a,124a,24b,124bmay define an arc orthogonal to the longitudinal axis18corresponding to an outer diameter of the graft body12with the arc length being a predetermined portion of the entire circumference, e.g., depending on the number of zigzag members24,124and the desired circumferential coverage for the loop region20.

For example,FIGS.4A-4Dshow an exemplary embodiment in which the reinforcement elements24include a pair of similar zigzag members24(1),24(2) offset about one hundred eighty degrees (180°) from one another around the circumference of the graft body12. Each zigzag member24includes alternating loops, i.e., peaks24aand valleys24balternating along the length of the loop region20, that extend only partially around the circumference of the graft body12, as shown inFIGS.4A and4B. The alternating loops of each zigzag member24may extend more than halfway around the circumference, i.e., greater than one hundred eighty degrees (180°), e.g., between about 180-300°, with the zigzag members24offset axially from one another by one loop such that the adjacent loops24a,24bof the zigzag members24nest at least partially between one another along the length of the loop region20. For example, if each zigzag member24defines a 180° arc, the entire periphery may be covered; if each zigzag member24defines an arc greater than 180°, the zigzag members24may nest and overlap, thereby increasing the rigidity of the support provided.

For example, as can be seen inFIG.4C(a two-dimensional schematic of the zigzag members shown inFIGS.4A and4B), in this configuration, the peaks24a(1) of the first zigzag member24(1) may be axially aligned with adjacent valleys24b(2) of the second zigzag member24(2) along one side of the graft body12(i.e., above the axis18, which is the central axis of curvature along the loop region20), while the valleys24b(1) of the first zigzag member24(1) may be axially aligned with adjacent peaks24a(2) of the second zigzag member24(2) on the opposite side (i.e., below the axis18). Thus, the zigzag members24may define a “clamshell” that wraps around the graft body12and partially interlock or overlap to support the graft body12in bending. Further, providing axial alignment of the loops24a,24bmay create an axial “spine”26along one side of the graft body12, which may have greater strut density and therefore provide greater support than an opposite side of the graft body12. For example, as shown inFIG.4D, the spine26may be positioned along an inner radius of the curve of the loop region20to provide greater support along the inside of the curve, which would otherwise be more likely to kink or buckle given axially compressive forces that may be encountered when the loop region20is bent. The side opposite the spine26, e.g., positioned along an outer radius of the curve of the loop region, has less strut density and therefore may provide less support, but the outside of the curve may need less support, e.g., since the outside of the curve would subject to axially tensile forces when the loop region20is bent.

Although two zigzag members24are shown, alternatively, more than two zigzag members, e.g., three, four, or more (not shown), may be provided that extend axially along the cannulation region30that include alternating loops that extend around a portion of the circumference of the graft body12. In this alternative, the zigzag members may be distributed around the circumference such that alternating loops of adjacent zigzag members partially overlap. For example, with four zigzag members, the alternating loops of each zigzag member may define an arc greater than one quarter of the circumference, i.e., greater than ninety degrees (90°), such that the peaks and valleys are nested between corresponding valleys and peaks of the circumferentially adjacent zigzag member.

Alternatively, turning toFIGS.5A-5C, the reinforcement element may include a single zigzag member124that extends partially or entirely around the circumference of the graft body112along the desired length of the loop region20. For example, as can be seen inFIG.5C(a two-dimensional schematic of the zigzag member124shown inFIGS.5A and5B), in this configuration, the upper loops124aof the zigzag member124may be axially aligned with adjacent lower loops124b. This axial alignment of the loops124a,124bmay also create an axial “spine”126along one side of the graft body12, which may have greater strut density and therefore provide greater support than an opposite side of the graft body12.

For example, in one embodiment, the spine126may be positioned along an inner radius of the curve of the loop region20to provide greater support along the inside of the curve, as described above. Alternatively, as shown inFIG.3, the spine26may be positioned at another circumferential location, e.g., between the inner and outer radius of the curve, e.g., offset about ninety degrees (90°) around the circumference from the inner radius of the curve. In an exemplary embodiment, the zigzag member124may be formed by wrapping a plastic wire element or filament around a cylindrical mandrel (not shown), e.g., having an outer diameter similar to the outer diameter of the loop region20. For example, a second smaller mandrel may be positioned adjacent the cylindrical mandrel, and a wire element for the zigzag member124may be wound partially around the cylindrical mandrel in a first circumferential direction until it is adjacent the smaller mandrel, whereupon the wire element may be wound around the smaller mandrel and then wrapped in a second circumferential direction around the cylindrical mandrel (opposite the first direction) until the wire element again reaches the smaller mandrel. The wire element may be wound around the smaller mandrel and wrapped in the first direction again, with this process being repeated as the wire element winds down the length of the cylindrical mandrel.

The wire element may be heat treated or otherwise processed to set the resulting shape into the wire element, whereupon the cylindrical and smaller mandrels may be removed to provide the zigzag member124, which may then be attached to the graft body12. For example, if the wire element is formed from nylon or other thermoplastic, hot air may be applied to the wire element/mandrels assembly to remove stress and/or set the shape into the zigzag member124before removing the mandrels. The zigzag member124may then be positioned around the graft body112and attached thereto along a desired length of the loop region, as described elsewhere herein. Alternatively, the smaller mandrel may remain interwoven with the wire element after removing the cylindrical mandrel, and the resulting zigzag member124may be positioned around and/or attached to the graft body12, whereupon the smaller mandrel may be removed.

One advantage of axially oriented zigzag reinforcement elements is that the reinforcement elements may accommodate axial elongation or compression of the loop region20, e.g., due to bending or other movement. If additional axial reinforcement is desired, the number of zigzag periods per unit length of the loop region20may be adjusted to provide a desired axial rigidity. Another advantage of zigzag reinforcement elements is that the asymmetrical geometry resulting from the zigzag pattern may provide a visual indicator of rotational orientation of the graft10, e.g., under fluoroscopy or other external imaging, without the need to provide additional markers on the graft10. For example, before introducing a needle or other device through the cannulation region30, external imaging may be used to confirm the orientation of the reinforcement elements and/or loop region20to ensure that the needle is inserted through a supported region.

Turning toFIGS.6A and6B, another embodiment of a tubular graft110is shown that includes an intermediate loop region120and a pair of self-sealing cannulation regions130on either side of the loop region120. Similar to the previous embodiments, the graft110includes an elongate tubular graft body112including first and second ends114a,114band a lumen116extending between the ends114a,114b. Also similar to the previous embodiments, the loop region120may include one or more reinforcement elements (not shown). Alternatively, as shown inFIGS.6C and6D, a tubular graft110′ may be provided that includes a single cannulation region130on a tubular graft body112, i.e., without a loop region.

As shown, the cannulation region(s)130include one or more reinforcement elements140embedded in or surrounding base material142, also similar to the previous embodiments. However, as shown inFIGS.6E-6G, in this embodiment the reinforcement element is a helical coil140that extends around and along the cannulation region(s)130. As can be seen inFIG.6E, the helical coil140may be wrapped or otherwise positioned around the outer surface of the graft body112and then embedded within or surrounding the base material142, e.g., silicone or other elastomeric material (not shown), similar to other embodiments herein and in the applications incorporated by reference herein. The helical coil140may be formed from metal, e.g., stainless steel, Nitinol, and the like, or other elastic or superelastic material, e.g., by laser cutting, mechanically cutting, stamping, machining, and the like, or from wire that may be formed into the spiral shape, similar to other embodiments herein.

Turning toFIGS.6F and6G, in an exemplary embodiment, the helical coil140may have a relaxed or low energy state in which adjacent coils contact one another with little or no gaps between the adjacent coils, e.g., as shown inFIG.6F. During assembly, the helical coil140may be stretched longitudinally to create gaps or spaces between adjacent coils, e.g., having a substantially uniform or other desired spacing, as shown inFIG.6G. The helical coil140may then be embedded within or around base material (not shown) to provide a self-sealing structure. When the helical coil140is released after being embedded in the base material, the helical coil140will be biased to return to its low energy state. Consequently, the helical coil140may apply a primarily axially compressive force to the base material (and to the underlying graft body112given the compressive force and greater stiffness of the helical coil140compared to the material of the graft body112), which may enhance sealing when a needle or other device is introduced through the structure. Optionally, the helical coil140may be sized to apply a radially compressive force to the base material142, e.g., by sizing the helical coil140to have a relaxed or low energy diameter smaller than the graft body112. In another alternative, the helical coil140may be embedded within the base material142in a relaxed and/or other low energy state, e.g., such that the helical coil140does not impose a radial and/or axial compressive force to the base material142. Such a configuration may provide support for the internal lumen116of the graft body112, e.g., to prevent the lumen116from being crushed when external pressure is applied, e.g., externally to the patient's skin overlying the graft110.

In an exemplary embodiment, the base material may be formed directly around the graft body112and helical coil140, e.g., by placing the helical coil140(in its stretched and/or radially expanded state) and desired length of the graft body112within a cavity of a mold and filling the cavity with base material. Alternatively, one or more layers of base material, e.g., in sheet or tubular form, may be wrapped, slid, or otherwise applied around the graft body112, e.g., a first layer between the helical coil140and the graft body112and a second layer over the helical coil140(not shown). The base material may be cured, heated, and/or otherwise processed to embed the helical coil140within the base material and/or to attach the base material and helical coil140to the graft body112. Optionally, an outer layer (not shown) may be applied over the base material after curing, e.g., an ePTFE sleeve similar to that shown inFIG.2Band/or fabric may be applied over exposed surfaces to provide a desired finish for the cannulation region30.

In a further alternative, the helical coil140may be embedded (again in its stretched state) within base material formed into a tubular sleeve, and then applied over and substantially permanently attached to the graft body112, e.g., by bonding with adhesive, fusing, and the like, as described in the applications incorporated by reference herein. Optionally, in this alternative, fabric may be applied over exposed surfaces before attaching the sleeve to the graft body112or an outer layer (not shown) may be applied over the sleeve after attachment to the graft body112. Additional information regarding methods for forming a cannulation region including the helical coil140embedded within base material may be found in the applications incorporated by reference herein.

In other alternatives, multiple stretched helical coils may be embedded within base material (and subsequently released) to provide the cannulation region. For example,FIGS.7A-7Cshow another embodiment of a tubular graft110″ that includes a cannulation region130″ on a graft body112, including first and second helical coils140a,″140b″ embedded within base material142.″ Optionally, the cannulation region130″ may include an outer sleeve144″ and/or fabric covering, similar to other embodiments herein. As best seen inFIGS.7A and7B, the first helical coil140a″ has windings extending in a first helical direction, and the second helical coil140b″ has windings extending in a second helical direction opposite the first direction. In addition, as shown inFIG.7D, the second helical coil140b″ has a diameter greater than the first helical coil140a″ such that the second helical coil140b″ may be positioned concentrically around the first helical coil140a″ (i.e., without braiding the helical coils together). In one embodiment, the diameters may be set such that the second helical coil140b″ may contact the first helical coil140a″ at overlap points, or, alternatively, the second helical coil140b″ may be spaced apart from the first helical coil140a″ such that base material142″ flows or is otherwise located between the helical coils140″ to space them apart from one another. This configuration may provide more uniform axial compression along the cannulation region130″ since any torsional forces between the helical coils may cancel each other out. In addition or alternatively, the overlapping helical coils140″ may provide a more uniform outer surface, e.g., preventing the base material142″ from bulging outwardly between the helical coils140.″

Turning toFIGS.8A-8C, in another alternative, a cannulation region130″′ may be provided on a tubular graft110″′ that includes two helical coils140″′ with windings that extend in the same helical direction, i.e., with a second helical coil140b″′ disposed concentrically around a first helical coil140a″′ as shown inFIG.8D. In this alternative, the windings of the second helical coil140b″′ may be axially aligned with windings of the first helical coil140a″′ (in phase, e.g., as shown inFIG.8E) or they may be offset from one another (out of phase, e.g., as shown inFIG.8D), as desired. Alternatively, two (or more) helical coils may be embedded together within the base material that have the same relaxed diameter but are offset axially from one another, e.g., by a half period or other desired spacing.

Returning toFIGS.6A-6C, a tubular graft110may be implanted within a patient's body, e.g., within the patient's forearm to provide arterial and venous access via cannulation regions130(including one or more helical coils140embedded in base material142). When it is desired to access the lumen116of the graft110, a needle and/or other device (not shown) may be introduced through the patient's skin overlying the graft110, and directed through one of the cannulation regions130into the lumen116. Where the cannulation region130includes a helical coil140, as shown inFIG.6A(or multiple coils140″ or140″′ as shown inFIGS.7A-7C or8A-8C), the needle may pass through one of the gaps between the spaced apart windings into the lumen of the graft body112. Optionally, the helical coil(s)140(140,″140″′) may have a rounded or other cross-section to facilitate the device passing between adjacent windings. When the needle or other device is removed, the axial compressive force applied by the helical coil(s)140(140,″140″′) may bias the base material142(142,″142″′) to close the puncture site, thereby maintaining a substantially fluid-tight seal in the wall of the tubular graft110(110,″110″′). In addition, the helical coil(s)140(140,″140″′) may prevent accidental leakage from graft110, e.g., subcutaneous or subdermal bleeding resulting from infiltration, if the needle is accidentally inserted entirely through the graft body112and out the opposite side of the cannulation region130since the helical coil(s)140also applies an axial compressive force along the posterior side of the cannulation region130.

Turning toFIGS.9A-9D, still another embodiment of a reinforcement member is shown, namely a zigzag member240that extends along the length of a cannulation region of a tubular graft (or alternatively, the zigzag member240may be embedded in base material for a patch, similar to other embodiments herein), such as the cannulation regions30shown inFIG.1. As can be seen inFIGS.9A-9C, the zigzag member240may be wrapped or otherwise positioned around the outer surface of a tubular graft body212and then embedded within or surrounding base material242, e.g., silicone or other elastomeric material, similar to other embodiments herein and in the applications incorporated by reference herein. As best seen inFIG.7D, the zigzag member240includes alternating loops (e.g., peaks240aand valleys240b) that extend at least partially around the circumference of the graft body212and alternate along the length of the cannulation region. Thus, the loops240a,240bmay define an arc orthogonal to the longitudinal axis218corresponding to an outer diameter of the graft body212with the arc length being a predetermined portion of the entire circumference.

For example,FIG.9Cshows a cross-section of the zigzag member240embedded in base material242that extends only partially around the circumference of the graft body212(shown in phantom), e.g., thereby defining an arc angle θ, e.g., between about 180-360° or between about 180-300°, around the circumference. In this embodiment, the resulting cannulation region may only extend partially around the device body212and so, during implantation, the resulting tubular graft10may be implanted to orient the cannulation region anteriorly, i.e., towards the skin through which the cannulation region would be accessed.

Turning toFIGS.10A-10D, another embodiment is shown that includes a pair of reinforcement members240(1),240(2) embedded within base material242and attached around a tubular graft body212to provide a cannulation region230(or embedded within base material for a patch, similar to other embodiments herein). Each reinforcement member240may be formed as a zigzag member similar to that shown inFIG.9D, i.e., including alternating loops (e.g., peaks240aand valleys240b) that extend at least partially around the circumference of the graft body212and alternate along the length of the cannulation region. Alternatively, one or both zigzag member240may define a more complicated repeating pattern, e.g., having a shape similar to the zigzag member340shown inFIG.11, which defines nonlinear peaks340aand valleys340b. This alternative may provide the ability to alter the amount of compression along the arc of the pattern or influence the final geometry of the lumen. For example, more complicated shapes may allow for controlling the degree of compression in any location along the cannulation region230and/or control the specific geometry of the areas not covered by the zigzag member340to facilitate minimized contact between a needle and the zigzag member340.

As can be seen inFIGS.10C and10D, the first zigzag member240(1) defines a first radius of curvature that is larger than the outer diameter of the graft body212and the second zigzag member240(2) defines a second radius of curvature that is larger than the first radius such that the second zigzag member240(2) is spaced apart radially outwardly from the first zigzag member240(1), e.g., by a desired distance6between about zero and five millimeters (0-5.0 mm). Alternatively, the zigzag members240may be biased to the same diameter but may be offset axially from one another, e.g., by half a period or other desired spacing.

In addition, as can be seen inFIGS.10A and10B, the zigzag members240may be offset axially from one another, e.g., by half a period, such that the peaks and valleys are spaced uniformly along the cannulation region. Providing overlapping zigzag members240may provide more uniform compressive forces to the base material242, may reduce bulging, and/or may provide greater wire density to the base material242, which may enhance self-sealing of the cannulation region after being punctured, similar to other embodiments described elsewhere herein. In addition, having inner and outer zigzag members240may provide more uniform compressive, i.e., sealing forces, through the thickness of the base material242.

Optionally, the properties of the inner and outer zigzag members240may be varied, i.e., with the outer zigzag member240(2) having different elasticities, thicknesses, and/or other mechanical properties, e.g., to provide different compliances between the zigzag members240, which may vary the properties towards the inner and outer surfaces of the cannulation region230. For example, depending on where the neutral axis is along the cannulation region, greater or lesser compression by the inner and/or outer members240may keep the cannulation region230from bowing or bending in an undesirable manner. In addition or alternatively, the shape and/or other mechanical properties of the zigzag members240may be varied along their lengths, e.g., to provide different compliances and/or other properties along the length of the cannulation region230.

Turning toFIGS.12A-12F, an exemplary embodiment of a self-sealing patch430is shown that includes a plurality of reinforcement elements440embedded within base material442, e.g., similar to the cannulation regions described above. Generally, the patch430is an elongate body including first and second ends432and defining a “C” shaped cross-section that includes opposing side edges434extending between the opposite ends432, thereby defining an inner lumen or recess436.

As best seen inFIG.12E, the patch430may be formed as a cuff, defining an arc greater than one hundred eighty degrees (180°), e.g., between about 180-360° or between about 180-300°, sized to receive a tubular structure (not shown) within the recess436. Alternatively, the patch430may have a substantially planar or curved shape (not shown), e.g., such that an inner surface of the patch430may be attached to a tissue or other body structure, as described in the applications incorporated by reference herein. For example, the reinforcement elements440and base material442may be sufficiently flexible such that the side edges434may be separated to allow the patch430to be positioned over and around a tubular structure, such as a tubular graft (not shown), e.g., similar to the grafts described elsewhere herein and in the applications incorporated by reference herein.

As best seen inFIG.12E, the reinforcement elements440include an inner zigzag member440aand an outer zigzag member440b. Each zigzag member440may include alternating loops (e.g., peaks and valleys) that extend at least partially around the circumference of the patch430and alternate along a desired length of the patch430. In the embodiment shown, adjacent peaks and valleys of each zigzag member440are spaced apart axially, and the zigzag members440are offset axially from one another such that the peaks of one zigzag member440aalong one side edge434are axially aligned with the valleys of the other zigzag member440bon the opposite side edge434.

Similar to previous embodiments, the outer member440bmay have a larger diameter than the inner member440asuch that the outer member440bmay be disposed concentrically around the inner member440a(i.e., without braiding or otherwise overlapping the inner member440aover the outer member440b). In addition, the outer member440bmay be spaced apart from the inner member440a, i.e., such that base material442is disposed between the members440, or, the outer member440bmay contact the inner member440a, e.g., at overlap points441at the top of the patch430, best seen inFIG.12B.

Turning toFIGS.13A-13F, another exemplary embodiment of a self-sealing patch530is shown that includes a plurality of reinforcement elements540embedded within base material542. Generally, similar to the patch430, the patch530is an elongate body including first and second ends532and defining a “C” shaped cross-section that includes opposing side edges534extending between the opposite ends532, thereby defining an inner lumen or recess536. Optionally, as shown, the side edges534may be beveled and/or rounded at the ends532, e.g., to facilitate positioning the patch530over a tubular structure.

In this embodiment, the reinforcement elements540also include an inner zigzag member540aand an outer zigzag member540bdisposed concentrically around the inner member540a. As best seen inFIG.13E, each zigzag member540may include alternating loops (e.g., peaks and valleys) that extend at least partially around the circumference of the patch530and alternate along a desired length of the patch530, similar to the previous embodiments. In this embodiment, the arc of the patch530is smaller than that of the patch430and the zigzag members540have shorter circumferential amplitudes along the length of the patch530than the zigzag members440. It will be appreciated that the shape and/or period of the zigzag members440,540may be varied to provide desired compliances and/or other mechanical properties, as described previously for other reinforcement elements.

Exemplary embodiments of the present invention are described above. Those skilled in the art will recognize that many embodiments are possible within the scope of the invention. Other variations, modifications, and combinations of the various components and methods described herein can certainly be made and still fall within the scope of the invention. For example, any of the devices described herein may be combined with any of the delivery systems and methods also described herein.

While embodiments of the present invention have been shown and described, various modifications may be made without departing from the scope of the present invention. The invention, therefore, should not be limited, except to the following claims, and their equivalents.