Composite prosthesis with external polymeric support structure and methods of manufacturing the same

A prosthesis including a support structure for enhancing kink and/or crush resistance. The support structure is connected to an outer surface of the prosthesis and includes at least two components, one of which has a lower melting point than the other. The component with the lower melting point is used to connect the support structure to the outer surface of the prosthesis.

FIELD OF THE INVENTION

The present invention relates generally to an implantable device. More particularly, the present invention relates to a prosthesis, such as a graft, including a support structure providing, e.g., enhanced kink and/or crush resistance.

BACKGROUND OF THE INVENTION

Implantable devices are commonly used in medical applications. One of the more common device structures includes tubular prostheses, which may be used as vascular grafts to replace or repair damaged or diseased blood vessels. To maximize the effectiveness of such a prosthesis, it should be designed with characteristics which closely resemble that of the natural body lumen which it is repairing or replacing.

One form of a conventional tubular prosthesis specifically used for vascular grafts includes a textile tubular structure formed by weaving, knitting or braiding synthetic fibers into a tubular configuration. Tubular textile structures have the advantage of being naturally porous, which allows desired tissue ingrowth and assimilation into the body. This porosity, which allows for ingrowth of surrounding tissue, must be balanced with fluid tightness so as to minimize leakage during the initial implantation stage. Other tubular prosthesis are formed of expanded polytetrafluoroethylene (ePTFE), which may be used for smaller diameter prosthesis.

Composite ePTFE textile grafts are also known. For example, U.S. Patent Publication No. 2003/0139806 describes an inner layer of ePTFE and an outer layer of textile material bonded together by an elastomeric bonding agent to form a vascular prosthesis.

It is known to provide enhanced kink and crush resistance properties to ePTFE grafts by directly attaching a spirally wrapped polymeric coil or support element made of PTFE. The ePTFE graft is heated to a temperature sufficient to assure that the PTFE coil bonds to the graft outer surface. This method, however, does not necessarily work well for composite grafts where the material of the wrapped support structure is made from a substantially different material from the underlying graft material. For example, when the underlying graft has a textile surface, attempting to attach a wrapped PTFE support member through conventional melting methods would likely weaken the textile layer because the melting temperature of PTFE (327° C.) is substantially higher than the melting temperature range of conventional implantable textiles, such as Dacron® (polyethylenetherephthalate, 240-258° C.). This holds true for other externally wrapped support structures, which have a melting temperature range above that of the underlying graft body.

Joining of very different materials to form an integrated assembly has many challenges associated with the physical and chemical differences of the materials. For example, in some instances, a wrapped support structure is intended to be attached in a manner which prevents it from being removed without damaging the underlying graft. In other cases, a wrapped support structure must be attached in a manner sufficient to perform its kink and crush resistance role, but allow for removal without damaging the underlying graft body. Such a removable support structure would allow the physician to tailor the graft to the patient, without risk of loss of structural integrity of the overall graft structure. Differences in such inherent properties as melting temperatures, surface properties, molecular weights, biocompatibility, flexibility, solubility, as well as elongation moduli, are some of the contributing factors which make it difficult to join dissimilar polymeric structures together to make an implantable prosthesis having crush and kink resistance.

Therefore, there is a need for a composite graft that can be securably attached to a coil or other external support element without compromising the graft, and which overcomes the difficulties associated with joining dissimilar materials.

SUMMARY OF THE INVENTION

An example embodiment of the present invention provides an implantable prosthesis which includes: (a) a generally tubular body including an outer textile surface; and (b) a support structure attached to the outer textile surface of the body and configured to increase at least one of the kink and crush resistance of the body. The support structure includes a first component and a second component. The second component (i) including a polymeric material, (ii) having a lower melting temperature than that of the first component and the body, and (iii) connecting the first component to the body.

According to an example embodiment, the body of the implantable prosthesis may include an inner layer made from a biocompatible polymer.

According to an example embodiment, the outer textile surface may include the outer surface of an outer textile layer including filaments or yarns with interstices or pores between them. The second component extends into the interstices or pores and thereby mechanically connects the first component of the support structure to the outer textile layer.

According to an example embodiment, the outer textile layer includes a knit, weave or braid pattern of the filaments or yarns and wherein the second component of the support structure is removably connected to the outer textile layer such that removal of the first component does not substantially damage the pattern. The textile pattern of the invention may be chosen from any useful pattern, including but not limited to knits, weaves, braids, or other spun fiber constructions.

According to an example embodiment, the support structure may be configured such that removal of the first component from the outer textile layer removes a portion of the second component while leaving a remainder of the second component connected to the outer textile layer.

According to an example embodiment, a biocompatible elastomeric bonding agent bonds an outer surface of the inner layer to an inner surface of the outer textile layer.

According to an example embodiment, the first component has a melting temperature of approximately 130° C.-170° C. and the second component has a melting temperature of approximately 60° C.-105° C.

According to an example embodiment, the first component is made from polypropylene.

According to an example embodiment, the second component is made from polyethylene.

According to an example embodiment, the support structure is wrapped about the outer textile surface. Various forms of wrapping may be used, including helical wrapping.

According to an example embodiment, the inner layer is made from at least one of ePTFE, polyurethane, silicone, and an acrylate. Combinations of biocompatible polymers may also be used.

According to an example embodiment, the inner layer is made from ePTFE.

According to an example embodiment, the second component is disposed about the first component. Desirably, the first component is a core component and the second component is a layer or sheath that partially or completely covers the core.

According to an example embodiment, there is provided an implantable prosthesis which includes: (a) a generally tubular body which includes an inner biocompatible layer (referred to as a luminal or blood-contacting layer), and an outer textile layer disposed about the inner biocompatible layer; and (b) a support structure attached to the outer textile layer and configured to increase at least one of the kink and crush resistance of the body, the support structure including a bead or coil having a core component and an outer sheath component surrounding the core component, the outer sheath component being a polymer having a melting temperature lower than the melting temperature of the core component and lower than the melting temperature of the body. Desirably, the core component is also a polymer component. The support structure may be formed by coating the core component with the sheath component or by co-extrusion techniques.

A method of preparing an implantable prosthesis according to an example embodiment of the present invention includes: (a) applying a support structure to an outer textile surface of a generally tubular body of the prosthesis, the support structure including a first component and a second component disposed about the first component, the second component being polymeric and having a lower melting temperature than that of the first component and the body; and (b) melting the second component, and not the first component or the body, so as to cause the second component to connect the first component to the body.

According to an example embodiment, the method further includes the preliminary steps of forming the body by disposing a textile outer layer over a biocompatible polymeric inner layer and connecting the outer and inner layers using a biocompatible elastomeric bonding agent.

A method of implanting a prosthesis into a subject according to an example embodiment of the present invention includes the steps of: (a) determining an appropriate size of the prosthesis for the subject, the prosthesis including a generally tubular body and a support structure attached to an outer surface of the body and configured to increase at least one of the kink and crush resistance of the body, the support structure including a first component and a second component, the second component having a lower melting temperature than that of the first component and the body, the second component connecting the first component to the body; (b) removing the first component from at least one end of the prosthesis consistent with the appropriate size while leaving the support structure connected along a remainder of the body; and (c) implanting the prosthesis in the subject.

Combinations of any of the aforementioned example embodiments are included as part of the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

FIG. 1shows a prosthesis10according to an example embodiment of the present invention. The prosthesis10may be generally tubular, and includes a composite implantable prosthesis having an inner layer14, e.g., a tube made from a biocompatible polymer, and an outer layer12, e.g., a tubular textile layer, at least partially disposed about the inner layer14. The prosthesis10may have any desired thickness, e.g., 0.1 mm to about 2 mm, the thickness being measured from the outer surface of the device to the inner surface.

As detailed further below, the two layers12,14may be joined, e.g., using a bonding agent, and supported by a support structure22. The support structure22includes a first material and a second material disposed on the first material and having a lower melting point than the first material. This novel support structure allows the graft to be heated to a temperature sufficient to assure bonding of the support structure to the graft without compromising the graft.

Composite Prosthesis

Inner layer14may be made from of a biocompatible material, such as a biocompatible polymer, e.g., ePTFE, polyurethane, acrylates, silicones and copolymers and combinations thereof. In one embodiment, the inner layer14is made from at least one of ePTFE, polyurethane, silicone, and an acrylate.

Outer textile layer12may be formed from a biocompatible material having at least one different property than inner layer14. For example, outer textile layer12may be a textile formed from yarns that may be flat, shaped, twisted, textured, pre-shrunk or un-shrunk. The yarns may be natural or synthetic, e.g., thermoplastic materials including, but not limited to, polyesters, polypropylenes, polyethylenes, polyurethanes, polynaphthalenes, polytetrafluoroethylenes, expanded polytetrafluoroethylene, and the like. The yarns may be of the multifilament, monofilament or spun types. Multifilament yarns offer increased flexibility. Monofilament yarns are useful for enhanced crush resistance.

As used herein, the term “PTFE” refers to polytetrafluoroethylene, and refers to any structure made at least partially of polytetrafluoroethylene. The term “ePTFE” refers to expanded polytetrafluoroethylene, and refers to any structure made at least partially of expanded polytetrafluoroethylene.

The inner layer14may be produced from the expansion of PTFE formed, e.g., in a paste extrusion process. The PTFE extrusion may be expanded and sintered in a manner well known in the art to form ePTFE having a microporous structure defined by nodes interconnected by elongate fibrils. The distance between the nodes, referred to as the internodal distance (IND), may be varied by the parameters employed during the expansion and sintering process. The resulting process of expansion and sintering yields pores within the structure of the inner layer14. The size of the pores are defined by the IND of the inner layer14.

The outer textile layer12may be designed as a tissue contacting surface in order to promote enhanced cellular ingrowth, which may contribute to the long term patency of the prosthesis. The inner layer14may be used as a blood contacting surface so as to minimize leakage and to provide a generally anti-thrombogetic surface. In certain situations, the layers may be reversed where indicated.

The inner layer14and the outer textile layer12may be bonded to each other, e.g., using a bonding agent20. The bonding agent may be applied as a solution to an outer surface of the inner layer14or to an inner surface of the outer textile layer12by a spray coating process. However, other known processes may be employed to apply the bonding agent20.

The bonding agent20may include, for example, various biocompatible, elastomeric bonding agents such as urethanes, polycarbonate urethanes, styrene/isobutylene/styrene block copolymers (SIBS), silicones, and combinations thereof. Other similar materials are contemplated. Most desirably, the bonding agent may include polycarbonate urethanes sold under the trade name CORETHANE® by Boston Scientific Corporation, Natick, Mass. This urethane is provided as an adhesive solution with preferably 7.5% Corethane, 2.5 W30, in dimethylacetamide (DMAc) solvent.

For inner layers14made from ePTFE, a highly hydrophobic material, it is useful to use a elastomeric bonding agent20, which makes it way into the micropores of the ePFTE structure, enhanced bonding. One example of a class of bonding agent with elastic properties are those formed from the reaction of alphatic macroglycols and aromatic or aliphatic diisocyanates.

Monofilament Biocompatible Polymeric Support Structure

With reference toFIGS. 2-4, the prosthesis10is wrapped with a support structure22in order to enhance crush and/or kink resistance. The support structure22may extend along the entire length of the prosthesis10or just along select portions, e.g., those requiring additional support. The support structure22may be produced separately from the prosthesis layers, e.g., by casting or extrusion.

The support structure22may include materials having different melting temperatures. As illustrated, support structure22has a first component23at least partially surrounded by a second component24which has a lower melting point than that of the first component23. The second component24is at least partially disposed about the first component24. The first component23and second component24may be coextruded. The second component24need not entirely surround the first component23prior to connection to the body10so long as second component24, upon melting and subsequently cooling, extends through interstices or pores in the outer textile layer12of the prosthesis10and also wraps around the first component23sufficient to create a hold on the first component23. The support structure22may have a core first component23surrounded by a sheath second component24.

The second component24is made from a material, desirably a polymeric material, having a lower melting point than the first component23. For example, the second component24may include a polyethylene polymer, and the first component23may include a polypropylene polymer. This permits the prosthesis10to be heated to a melting temperature high enough to melt the second component24of the support structure22, such that it may flow into interstices or pores of the textile layer12of the prosthesis10, but not high enough to melt the first component23of the support structure22or the inner layer14and outer textile layer12of the prosthesis10. Thus, the second component24connects the first component23to the prosthesis10.

The support structure22may have any cross-sectional configuration. The cross section of the support structure22may be selected so as to maximize the surface area through which it may be fused to the outer textile layer12of the prosthesis10. The cross section of the support structure22may also be selected, e.g., a semicircle or half moon, so as to, minimize the external irregularity or roughness of the prosthesis10by limiting the height of the support22above the outer textile layer12.

The overall size and geometry of the support structure22are adaptable depending on the material used and the desired end properties of the prosthesis10.

The support structure22may be attached to the outer textile layer12such that it is removable or non-removable, as further discussed herein. In one embodiment, the physician can remove or unravel the support structure22from the outer textile layer12in order to size or tailor the prosthesis10to the patient.

In another embodiment, the support structure22may be heated at a temperature, e.g., above 160° C., sufficient to cause both the first component23(i.e., the core) and the second component24(i.e., the sheath) to melt. If the polymeric support structure is not adequately disposed about or wrapped around the prosthesis, then it will simply melt off the surface of the prosthesis. However, if the polymeric support structure is contained during the melting process, then both polymers will flow into the outer textile layer12of the prosthesis10and flatten-down, or in some cases be recessed, to achieve a low profile allowing, e.g., for the use of a smaller diameter delivery mechanism. In some embodiments, the total profile will essentially be the same as or only nominally above the profile of the underlying prosthesis10.

In another embodiment, the support structure22may be applied to only a section of the base of the prosthesis10, for example, leaving the ends either unsupported or supported with a removable polymeric support to create a prosthesis that is customizable. The customizable ends will allow the physician to cut the prosthesis10to the appropriate length and still make the necessary sutures for implantation.

In an example embodiment, the first component23, e.g., made from polypropylene, has a melting point which is about 130° C.-170° C. and the second component24, e.g., made from polyethylene, has a melting point of about is 60° C.-105° C.

As shown inFIG. 2, prosthesis10has a polymeric support structure22wrapped helically around the prosthesis10and connected thereto. The polymeric support structure22of the prosthesis10as shown is a monofilament, but may be a braid of two or more, e.g., smaller, filaments. Alternatively, the polymeric support structure may be composed of two or more filaments wrapped independently about the outer textile layer12. Each filament may be composed of a single monofilament or may be composed of an arrangement of two or more filaments mutually intertwined, e.g., in a regular braid or twist pattern.

The support structure22may be comprised of a single filament length wrapped helically around the tube for the length of the outer textile layer12. Alternatively, one or more support structures may extend longitudinally along a length of the prosthesis10. Further, the filament component may be discontinuous, being comprised of more than one segment of filament wrapped or otherwise arranged along the outer textile layer12. If more than one segment is employed, the segments may be wrapped sequentially, so that the ends of each segment are juxtaposed with each adjacent segment end and attaching each segment to the outer textile layer12so that segment ends are as close to each other in the longitudinal dimension as possible. Arrangements in which such segments are not matched in helical and/or longitudinal position are also contemplated as an embodiment of the invention. Alternatively, when more than one filament segment is used, the segments may overlap longitudinally such that two or more segments, whether of identical or non-identical lengths and/or diameters, may be fused to the outer textile layer12at any plane along the length of the prosthesis10.

In an example embodiment, the support structure22may be wrapped around the outer textile layer12, e.g., at an angle of winding, relative to the axis, of from about 30° to about less than 90°.

In an example embodiment with more than one support structure wrapped about the outer textile layer12, the angle of winding of each the support structures22may be equal to that of the others so that the support structures22are substantially mutually parallel, i.e., non-overlapping.

In another embodiment, the support structure22may be wrapped under tension against the outer textile layer12of the prosthesis10and may be heated to a temperature sufficient to melt the second component24of the support structure22. The heating is conducted such that the second component24flows into and removably adheres to the outer textile layer12of the prosthesis10while also remaining sufficiently disposed about first component23. Second component24cools on first component23and is configured about first component23in a manner allowing it to physically hold onto first component23and resist up to a predetermined level of pulling force separating first component23from outer textile layer12, e.g., 10 grams to 300 grams. The connection between the second component24of the support structure22and the outer textile layer12of the prosthesis10is strong enough to withstand such predetermined pulling force and remains intact, thus preserving the integrity of the outer textile layer12of the prosthesis10, even upon removal of first component23from the prosthesis10(although removal of the first component23may take a portion of the second component24of the support structure22with it). After heating, a removable support structure22is created. This permits the physician with the option of customizing the supported length to suit his/her needs and provide an area that is capable of being sutured.

In another embodiment, the support structure22may be wrapped under tension against the outer textile layer12, and may be heated to a temperature to melt both the first component23and the second component24and compressed against the second component24of the prosthesis10to effectuate a non-removable adherence to the prosthesis10. After heating, a low profile non-removable support is created.

In another embodiment, if the ends of the prosthesis10are completely unsupported or supported with a removable polymeric support material, it will create a prosthesis with a support structure that is customizable. The customizable ends will allow the physician to cut the prosthesis10to the appropriate length and still be able to make the necessary sutures.

The support structure22may be wrapped around the outer textile layer12while under tension, otherwise the support structure22might slip and/or be displaced during manipulation prior to sintering. The tension level is sufficient to avoid slippage while low enough to avoid damage to the support structure22. The compression may be applied by a flexible tubular wrap or sheath. The flexible tubular wrap or sheath may be a shrink wrap silicone, or a textile wrap designed to tightly fit about the structure.

In one embodiment, the support structure22may be melted to the tubular outer textile layer12of the prosthesis. This allows the formation of a support structure22integrated with the prosthesis10without requiring additional means for causing the tubing and the polymeric support components to adhere to one another. The outer textile layer12may be made from a textile, e.g., woven or knit, including overlapping or interconnecting filaments or yarns forming interstices between the filament or yarns. The second component24of the support structure22extends into the interstices and thereby mechanically connects the first component23of the support structure22to the outer textile layer12.

Accordingly, adhesives, laminates or other physical means for maintaining the integrity of the composite prosthesis are rendered unnecessary, thus simplifying the structure of the prosthesis10and the method of its manufacture.

In another embodiment, the support structure22may be adhered or otherwise bonded to the prosthesis10. The material of the second component24of the support structure22may be adapted or chosen specifically to ensure an excellent bond with the outer textile layer12of the prosthesis while the first component23may be chosen to assure ideal physical support properties for the prosthesis.

In another embodiment, the support structure22may be melted to the outer textile layer12of the prosthesis10substantially continuously or discontinuously along the length of the prosthesis10.

In an example embodiment, the support structure22may be in the form of a bead and may be configured to be flat, square, or ribbon-like spherical elliptical or other shapes.

Methods of Assembly

Having described the prosthesis10of the present invention, an example method of manufacturing the prosthesis10in accordance with the present invention may now be described.

Generally, the prosthesis10is formed from an inner layer14, an outer textile layer12at least partially disposed about the inner layer14and joined thereto by a bonding agent20. A support structure22, made up of core material23and second component24, is applied to the outer textile layer12. The second component24is melted onto the outer textile layer12to thereby adhere the support structure22to the prosthesis10. The support structure22may be melted, for example, by application of heat at a temperature sufficient to melt the second component24but not the first component23(or core) of the support structure22.

The inner layer14of prosthesis10may be formed in a conventional forming process such as by tubular extrusion or by sheet extrusion where the sheet is formed into a tubular configuration. The inner layer14is placed over a stainless steel mandrel and the ends of the tube are secured. The prosthesis is then spray coated with an adhesive solution of anywhere from 1%-15% Corethane® urethane, 2.5 W30 in DMAc. As noted above, other adhesive solutions may also be employed. The coated inner layer2may be dried at room temperature. Alternatively, it may be placed in an oven heated in a range from 18° C. to 150° C. oven for 5 minutes to overnight to dry off the solution. If desired, the spray coating and drying process can be repeated multiple times to add more adhesive to the inner layer14. The inner layer14is then covered with the outer textile layer12to form the composite prosthesis10. One or more layers of resilient sheath, is then placed over the composite structure to hold the composite structure together and assure that complete contact and adequate pressure is maintained for bonding purposes. The assembly of the composite prosthesis within the sheath is placed in an oven and heated in a range of 180°-220° C. for approximately 5-30 minutes to bond the layers together.

One technique used to attach the support structure22to the outer textile layer12is shown inFIG. 4. In this example, prosthesis10is a graft composed of multiple layers including textile and ePTFE and has joined thereto, e.g., in a helical fashion therearound, a two-layer support structure22. In order to join the support structure22to the prosthesis10, the prosthesis10is placed over a solid mandrel15. Conventional external heating, e.g., by a convection oven, (arrows A), is applied to the support structure22positioned over the prosthesis10. While this is adequate to bond the support structure22to the outer layer12, heating in this manner may cause the second component24of the support structure to uncontrollably flow and create fillets13at the juncture of the support structure22and the outer textile layer12of the prosthesis10thereby forming a tent configuration between the outer textile layer12and the support structure22. This method of attachment via conventional external heating, as indicated by arrows A, results in a reduced peel strength of attachment that is undesirable and further causes an area of reduced flexibility due to the larger and thicker fillet areas formed by the melted polymer. While composite prostheses of the present invention formed in this manner results in a higher degree of crushed and kink resistance, the composite structure may lose flexibility which is desirable in an implantable prosthesis. Also, as noted there may be a tendency for the support structure to lose certain of its peel strength of attachment.

Referring now toFIG. 5, another technique for connecting the support structure22to the prosthesis10is described. The prosthesis10having support structure22, e.g., coiled therearound, is placed on a mandrel30, e.g., made from 316 stainless steel tubing. The mandrel30is heated from within the prosthesis10to effectuate melting of the support structure22to the prosthesis10. The heat is transferred in the direction of arrows B from the mandrel30to the prosthesis10. The mandrel may be heated in a wide variety of manners. The mandrel may be heated by applying heated fluids, such as liquid or high temperature granular solids such that the composite prosthesis is melted by raising the temperature of the support structure22above its melting point.

In accordance with one embodiment of the present invention, a heated circulating bath32of, e.g., fluid or granular solids, is heated to approximately above the melting point of at least the second region24of the support structure22, e.g., above about 60-105° C. A pump (not shown) circulates the heated material through the mandrel30. The heat from the material passing through the mandrel30is transferred through the wall of the mandrel (arrow B) and into the surface of the outer textile layer12of the prosthesis10sufficient to melt at least the second component24of the support surface22.

A pump (not shown) in the heater bath32circulates the heated material through the mandrel30and back into the bath32. The heat from the material passing through the mandrel30is transferred through a wall of the mandrel and through the prosthesis. The prosthesis is held in this state for enough time to melt just the second component24, e.g., made from polyethylene, of the support structure22in contact with the outer textile layer12of the prosthesis, e.g., made from ePTFE.

Attachment of the support structure22may also be effectuated by applying pressure, with or without heat, to compress the support structure22against the outer textile layer12to produce a low profile structure. The pressure may be applied, e.g., using a flexible wrapper sheath. The flexible wrapper sheath may be formed, e.g., from a textile or polymer.

It is also contemplated that the present technique could be used to cool products which require low temperature cycle. Alternatively, after heating the composite prosthesis the mandrel can be used to inject low temperature fluid into the line to rapidly cool the product. Temperature control or changes may be used to temper or anneal products to create various polymer microstructures for various performance criteria.

The attachment process described inFIG. 5may also be used with different support structures, for example, those made from a single material or multiple materials and wrapped in different configurations as well.

Use of a support structure22having a first component23with a melting point greater than the melting point of the second component24allows the appropriate amount of heat to be applied so that only the second component24melts, i.e., the heat applied is above the melting point of the second component24, but lower than the melting point of the first component23. The result of such melting is shown inFIG. 6. As can be seen, heat applied from within the prosthesis10effectuates melting of the outer layer material24such that it cools on the bottom of the inner layer material23, i.e., where the support structure22contacts the outer textile layer12of the prosthesis, and may partially reside or soak into the outer textile layer12, e.g., extending into interstices in the knit or woven structure of the outer textile layer12, serving to connect the first component23to the prosthesis10. The connection is strong enough to keep the support structure in place along the prosthesis10during use in a patient's body but also allows the support structure22to safely be pulled off the outer textile layer12, e.g., along the ends of the prosthesis10so as to allow sizing before implantation, without substantial damage to the, e.g., knit or woven pattern, of the outer textile layer12. The connection may be configured such that removal of the first component23from the outer textile layer12removes a portion of the second component24, while leaving a remainder of the second component24connected to the outer textile layer12.

According to another example method for making the prosthesis10, the end product of which is shown inFIG. 7, melting is performed at a temperature above the melting point of both the first component23and the second component24. In such an embodiment, the entire support structure22is at least partially melted and allowed to soak into and bond to the outer textile layer12, which provides for a non-removable lower profile support structure.

According to another example method for making the prosthesis10, this time a composite prosthesis structure having a ePTFE inner layer and a textile outer layer, the prosthesis is placed on a stainless steel mandrel and has a barium sulfate-containing polypropylene/polyethylene bicomponent monofilament support structure wrapped about it under tension. The barium sulfate is a radiopaque material and allows for visualization under fluoroscopy by the physician.

This sub-assembly is placed in a laboratory convection oven at 140° C. for 8 minutes. After the oven cycle, and once the prosthesis is cool, it can be removed from the mandrel. The result is a prosthesis with a traditional bead support structure that is radiopaque and removable to customize.

According to another example method of making prosthesis10, the prosthesis10is covered by a silicone tube, a layer of knit material, a second layer of silicone tube, and a PTFE tape wrap. The silicone-knit-silicone-PTFE covering is used to apply pressure to the prosthesis during the heating cycle. After heating the prosthesis at 170° C. for 8 minutes in a laboratory convection oven, the silicone-knit-silicone-PTFE covering is removed and discarded. The result is a prosthesis with a low profile, non-removable, radiopaque, support wrap that is melted into the outer layer of the prosthesis.

According to another embodiment of the invention, there is provided a method of implanting a prosthesis10into a subject according to an example embodiment of the present invention. The method includes the steps of: (a) determining an appropriate size of the prosthesis10for a subject, the prosthesis10including a generally tubular body and a support structure22attached to an outer surface of the body and configured to increase at least one of the kink and crush resistance of the body, the support structure22including a first component23and a second component24, the second component24having a lower melting temperature than that of the first component23and the body, the second component24connecting the first component23to the body; (b) removing the first component23from at least one end of the prosthesis10consistent with the appropriate size while leaving the support structure22connected along a remainder of the body; and (c) implanting the prosthesis10in the subject.

Various changes to the foregoing described and shown structures would now be evident to those skilled in the art. Accordingly, the particularly disclosed scope of the invention is set forth in the following claims.