Abstract
An endoprosthesis (1) comprising a body part (2), a first cover sheet (4), and a thrombogenic fiber (5), wherein the (5) fibers are attached to the endoprosthesis (1) by means of a fixation layer (7) and partially arranged between the first cover sheet (4) and the fixation layer (7).
Claims
1.-17. (canceled)
18. An endoprosthesis having a longitudinal axis, comprising: at least one body part; a first cover sheet; and at least one thrombogenic fiber wherein the endoprosthesis further comprises at least one fixation layer which attaches the at least one thrombogenic fiber to the endoprosthesis, wherein at least one of the at least one thrombogenic fiber, and a support structure for the thrombogenic fiber is at least partially arranged between the fixation layer and the first cover sheet.
19. The endoprosthesis according to claim 18, wherein the at least one thrombogenic fiber has at least a free end extending from the fixation layer and the first cover sheet.
20. The endoprosthesis according to claim 18, further comprising at least one support strip, wherein the at least one thrombogenic fiber is attached to the at least one support strip.
21. The endoprosthesis according to claim 20, wherein the at least one support strip is arranged between the first cover sheet and the at least one fixation layer.
22. The endoprosthesis according to claim 20, wherein at least one of the support strip and the fixation layer comprises an adhesive.
23. The endoprosthesis according to claim 22, wherein the adhesive is adapted such as to penetrate at least one of the first cover sheet and the fixation layer.
24. The endoprosthesis according to claim 22, wherein the adhesive is provided as an adhesive layer on the fixation layer.
25. The endoprosthesis according to claim 18, wherein at least one of the first cover sheet and the at least one fixation layer comprise PTFE.
26. The endoprosthesis according to claim 18, wherein the first cover sheet and the at least one fixation layer consist of the same material.
27. The endoprosthesis according to claim 18, wherein the at least one fixation layer is arranged such that a first and a second end portion of the at least one thrombogenic fiber extend from the fixation layer and the first cover sheet.
28. The endoprosthesis according to claim 18, wherein a first end portion of the at least one thrombogenic fiber is arranged between the fixation layer and the first cover sheet and a second end portion of the at least one thrombogenic fiber extends from the fixation layer and the first cover sheet.
29. The endoprosthesis according to claim 18, comprising at least two fixation layers, wherein the at least two fixation layers are separated by a space along the surface of the first cover sheet.
30. The endoprosthesis according to claim 18, wherein the at least one fixation layer has an elongated shape running in a direction parallel to the longitudinal axis of the endoprosthesis.
31. A method of producing an endoprosthesis, comprising: providing an endoprosthesis frame comprising a first cover sheet; providing at least one thrombogenic fiber; providing at least one fixation layer; arranging the at least one thrombogenic fiber on the first cover sheet; and attaching the thrombogenic fiber on the first cover sheet by fixing the fixation layer on the first cover sheet, wherein at least one of the at least one thrombogenic fiber and a support structure for the thrombogenic fiber is arranged at least partially between the fixation layer and the first cover sheet.
32. The method according to claim 31, wherein at least one support strip with the at least one thrombogenic fiber attached thereto is provided.
33. The method according to claim 31, wherein at least one of the at least one support strip and the at least one fixation layer comprises an adhesive, and the step of fixing the fixation layer comprises an activation of the adhesive.
34. The method according to claim 31, further comprising the step of providing at least one protection strip, releasably attaching it to the endoprosthesis, wherein, in its attached state, the protection strip retains the at least one thrombogenic fiber on a surface of the first cover sheet.
Description
[0038] In the following, the invention is described in detail with reference to the following figures:
[0039] FIG. 1: shows schematically an endoprosthesis according to the invention
[0040] FIG. 2a-2b: show a top view of a support strip and a side view when attached to an endoprosthesis
[0041] FIG. 3a-3b: show a top view of another support strip and a side view when attached to an endoprosthesis
[0042] FIG. 4: show different embodiments of fiber attachments
[0043] FIG. 5: schematically shows the method according to the invention
[0044] FIG. 6: shows a detailed illustration of an endoprosthesis
[0045] FIG. 1 shows an endoprosthesis 1 according to the invention comprising a body part 2 and a first cover sheet 4. A plurality of fibers 5 is attached to the first cover sheet 4 by means of a support strip (not shown) and a fixation strip 7. The support strips and the fixation layers exhibit an elongated shape and are running in the direction of the longitudinal axis L of the endoprosthesis 1.
[0046] FIG. 2a shows a support strip 6 with a plurality of fibers 5 attacked thereto. The support strip comprises a polyurethane as an adhesive composition. In this particular embodiment, the support strip has an elongated shape and the fibers are only extending on one side of the support strip.
[0047] FIG. 2b shows the support strip 6 of FIG. 2a in a crosssectional side view when fixed on the first surface 4 with a fixation layer 7. Because the fibers 5 are only attached on one side of the support strip 6, the fibers 5 only extend on one side of the fixation layer 7 as well.
[0048] FIG. 3a shows an alternative embodiment of a support strip 6. This support strip 6 exhibits an elongated shape with fibers 5 extending from both sides.
[0049] FIG. 3b shows the support strip 6 of FIG. 3a when fixed on the first cover sheet 4 by means of a fixation layer 7. The fibers 5 extend from the fixation layer 7 on both sides, corresponding to the fiber arrangement of the support strip.
[0050] FIG. 4a shows an embodiment of the endoprosthesis in a side view. In this particular embodiment, no support strip is used. Instead, the fiber 5 is arranged directly on the first cover sheet 4. The fixation layer is arranged over a first end portion 9 of the fiber 5, whereas a second end portion 10 of the fiber 5 extends from the fixation layer 7.
[0051] FIG. 4b shows an alternative embodiment of the endoprosthesis. In this particular embodiment, no support strip is used. Instead, the fiber 5 is arranged directly on the first cover sheet 4. A middle portion 11 of the fiber 5 is arranged between the first cover sheet 4 and the fixation layer 7. The first and second end portions 9, 10 of the fiber 5 extend away from the fixation layer.
[0052] FIG. 5 schematically shows the steps of the method according to the invention. In a first step (A), an endoprosthesis is provided. For simplicity, only the first cover sheet 4 is shown. Here, the first cover sheet consists of electrospun PTFE fibers. In another step (B), a support strip 6 that has fibers 5 attached to it on both sides is provided and arranged on the first cover sheet 4. Another step (C) comprises arranging protection strips 8 on the first cover sheet 4 and the fibers 5. The fibers 5 are retained close to the surface of the first cover sheet 4 and completely covered by the protection strips 8. The support strip 6 is not covered by the protection strips 8. In a next step (D), the endoprosthesis is provided with the fixation layer (7). Here, the fixation layer 7 consists of a pre-cut patch of electrospun PTFE fibers with an adhesive layer 7a of polyurethane. The fixation layer 7 is arranged on the support strip 6. The side of the fixation layer 7 with the adhesive layer 7a is oriented towards the support strip 6 and the first cover sheet 4. Finally (E), the protection strips 8 are removed. This releases the fibers 5 that now extend freely from the support strip 6 and the fixation layer 7. At this point, a heating and pressing step is used to press the fixation layer 7 towards the first cover sheet 4 and partially melt the adhesive layer of the fixation layer 7, which penetrates into the support strip 6, the first cover sheet 4, and the fixation layer 7, leading to enhanced fixation. Because of the melting and penetration of other layers, the adhesive layer 7a is no longer visible after this step.
[0053] FIG. 6 shows a particular embodiment of the endoprosthesis. This illustration corresponds to step E in FIG. 5. Here, the endoprosthesis frame comprises a metallic scaffold 3 that is arranged within the first cover sheet 4. In this particular embodiment, the endoprosthesis has several body elements 2, 13a, 13b, wherein two body elements 13a, 13b have a smaller diameter than another body part 2. The endoprosthesis 1 exhibits a Y-shape. The scaffold 3 consists of an interconnected grid made of a Nitinol shape memory metal. It is encapsulated by electrospun PTFE fibers that make up the first cover sheet. The fibers 5 are provided on a support strip 6 that is arranged on the first cover sheet 4. After the coating with another layer of electrospun PTFE fibers and the removal of the protection strips (not shown here), the support strip 6 is encapsulated in a sandwich-like structure in between the first cover sheet 4 and the fixation layer 7. The total thickness T of the endoprosthesis wall, comprising the first cover sheet 4, the scaffold 3, the support strip 6, and the fixation layer 7 is between 115 and 120 μm.
