Endoprosthesis and method of manufacturing an endoprosthesis

Abstract

Endoprosthesis (1) comprising a body portion (2), a first face layer (4) and thrombogenic fibers (5), wherein the fibers (5) are attached to the endoprosthesis (1) by means of a fixation layer (7) and are partially arranged between the first face layer (4) and the fixation layer (7).

Description

Technical Field

[0001] The present invention relates to an endoprosthesis and a method for producing an endoprosthesis, in particular a vascular or cardiac stent, according to the preambles of the independent claims. Background Art

[0002] Endoprostheses, particularly vascular and cardiac stents, are used to support blood vessels within the human body. For example, these endoprostheses can be placed in the appropriate location to treat occlusions or aneurysms. In occlusion treatment, the endoprosthesis keeps the blood vessels open to allow for unimpeded blood flow. In the case of aneurysms, the endoprosthesis can prevent blood from circulating within the aneurysm, thereby reducing the risk of rupture or further growth.

[0003] The use of thrombogenic elements on endoprostheses is known in the prior art. For example, WO 2013 / 182614 A1 discloses an endoprosthesis with a thrombogenic element that extends away from the body of the endoprosthesis and promotes thrombosis. This allows for the occlusion of aneurysms to enhance the aforementioned therapeutic effect.

[0004] However, currently known methods do not provide an easy way to post-fabricate the thrombogenic element to the endoprosthesis. The fixing and attachment of the thrombogenic element is often cumbersome and complex and is not generally universal. Summary of the Invention

[0005] It is therefore an object of the present invention to overcome the disadvantages of the prior art and in particular to provide an endoprosthesis and a method for producing an endoprosthesis in which thrombogenic elements can be easily added to the surface of the endoprosthesis, in particular in a universal manner and at selected locations of the endoprosthesis surface.

[0006] This and other objects are achieved by an endoprosthesis and a method according to the invention in accordance with the characterizing features of the independent claims.

[0007] According to the invention, the endoprosthesis, in particular a vascular stent and a cardiac stent, has a longitudinal axis and comprises at least one main body portion and a first surface layer. The main body portion preferably comprises a stent, in particular a stent arranged within the first surface layer. Additionally, the endoprosthesis comprises at least one thrombogenic fiber. Furthermore, the endoprosthesis comprises at least one fixing layer to which the at least one thrombogenic fiber is attached, preferably permanently attached, to the endoprosthesis. The at least one thrombogenic fiber and / or a support structure for the thrombogenic fiber is at least partially arranged between the fixing layer and the first surface layer.

[0008] For example, the support structure for the at least one thrombogenic fiber can be a support strip to which the fibers are attached. If no support structure is used, at least a portion of the fibers are arranged in a sandwich configuration between the anchoring layer and the first surface layer. If at least one fiber is attached to the support structure, only the support structure can be arranged between the first surface layer and the anchoring layer. However, it is also possible to arrange both the at least one fiber and the support structure in this manner, for example, if the anchoring layer extends above the support structure and also covers the at least one fiber. Alternatively, the at least one fiber can be arranged above or below the support structure, both of which are arranged between the anchoring layer and the first surface layer.

[0009] In a preferred embodiment, the at least one thrombogenic fiber has at least one portion, preferably a free end, extending from the fixing layer and the first facing layer. For example, the fixing layer may cover a segment of the fiber but not another segment thereof.

[0010] In another preferred embodiment, the endoprosthesis comprises at least one support strip, and the at least one thrombogenic fiber is attached to the at least one support strip. Attachment of the at least one fiber may comprise weaving, sewing, suturing, and / or gluing. Separate attachment of the fibers to the support strips particularly facilitates the production of preassembled components and, ultimately, the manufacture of the endoprosthesis.

[0011] In particular, a supporting strip may be arranged between the first surface layer and the at least one fixing layer.

[0012] In a particularly preferred embodiment, at least one of the support strip and the fixation layer comprises an adhesive. The adhesive enables easy attachment of the support structure to the first facing of the endoprosthesis.

[0013] In particular, the support strip and / or the fixing layer may comprise a hot melt adhesive which, in its molten state, has a contact angle on polytetrafluoroethylene (PTFE) of less than 45°, preferably less than 30°. Additionally or alternatively, the adhesive may also be adapted to be curable by electromagnetic radiation, in particular ultraviolet (UV) light, heat or oxygen.

[0014] More preferably, the adhesive is adapted to penetrate at least one of the first facing layer and the fixing layer, such as in particular in its molten state. In particular, the contact angle of the adhesive in the liquid state (before a hardening, annealing or drying step) on the first facing layer material is adapted so that it can fill the penetration pores in the first facing layer.

[0015] Preferably, the adhesive is provided as an adhesive layer on the fixing layer. For example, the adhesive can be provided as a polyurethane layer on the fixing layer.

[0016] In another preferred embodiment, at least one of the first surface layer and the at least one fixing layer comprises PTFE, in particular a plurality of electrospun fibers of PTFE.

[0017] In a preferred embodiment, the first surface layer and the at least one fixing layer are composed of the same material.

[0018] In a preferred embodiment, the endoprosthesis comprises at least one protective strip which is releasably attached to said endoprosthesis.In its attached state, the protective strip holds said at least one thrombogenic fiber to the surface of said first facing layer.

[0019] In a particularly preferred embodiment, the stent comprises a metallic material, in particular a shape memory metal, preferably an alloy comprising nickel and / or titanium.

[0020] In a preferred embodiment, the endoprosthesis comprises two body parts. The at least two body parts may, for example, be adapted to treat different blood vessel parts having different diameters. Such an endoprosthesis with more than one body part is disclosed in WO 2013 / 182614 A1.

[0021] In another preferred embodiment, the total thickness of the endoprosthesis wall may generally be less than 120 microns and / or greater than 115 microns.

[0022] In a preferred embodiment, the first and second ends of the at least one thrombogenic fiber extend from the fixing layer and the first facing layer.

[0023] In an alternative embodiment, a first end portion of at least one thrombogenic fiber is disposed between the fixing layer and the first facing layer. A second end portion of the at least one thrombogenic fiber extends from the fixing layer and the first facing layer.

[0024] In a further preferred embodiment, at least one of the fixing layers is arranged such that the first and second ends of the at least one thrombogenic fiber extend from the fixing layer and the first facing layer.

[0025] In yet another preferred embodiment, a first end portion of at least one of the thrombogenic fibers is disposed between the fixing layer and the first facing layer, and a second end portion of at least one of the thrombogenic fibers extends from the fixing layer and the first facing layer.

[0026] In a preferred embodiment, the endoprosthesis comprises at least two fixing layers separated by a gap along the surface of the first facing layer.

[0027] In a preferred embodiment, the at least one fixation layer has an elongated shape extending in a direction parallel to the longitudinal axis of the endoprosthesis.

[0028] The present invention also relates to a method of manufacturing an endoprosthesis, in particular an endoprosthesis as described herein.

[0029] The method according to the present invention comprises: in a first step, providing an endoprosthesis frame having a first surface layer. In a further step, providing a thrombogenic fiber and a fixing layer. The at least one thrombogenic fiber is arranged on the first surface layer. The thrombogenic fiber is arranged on the first surface layer by fixing the fixing layer to the first surface layer, wherein preferably, the at least one thrombogenic fiber is at least partially arranged between the fixing layer and the first surface layer.

[0030] In a preferred embodiment, the method further comprises providing a core shaft provided with a first surface layer and a support. In particular, the support can be arranged in the first surface layer.

[0031] In a preferred embodiment, at least one support strip is provided with said at least one thrombogenic fiber attached thereto.

[0032] In a preferred embodiment, at least one of the at least one support strip and the at least one fixing layer comprises an adhesive, preferably a hot melt adhesive. The step of fixing the fixing layer comprises activating the adhesive, preferably melting the hot melt adhesive. Alternatively, activating the adhesive may also comprise exposure to electromagnetic radiation, in particular UV radiation, heat, or oxygen.

[0033] In a preferred embodiment, the method further comprises the step of providing at least one protective strip, which is releasably attached to the endoprosthesis. In its attached state, the protective strip holds the at least one thrombogenic fiber to the surface of the first facing.

[0034] In a preferred embodiment, the step of providing a first facing comprises coating with a plurality of electrospun fibers.

[0035] In a preferred embodiment, the step of providing the fixing layer comprises coating with a plurality of electrospun fibers. Alternatively, the fixing layer can also be provided as a pre-cut sheet comprising a plurality of electrospun fibers. Preferably, such pre-cut sheet comprises an adhesive layer.

[0036] In particular, the electrospun fibers comprise, and preferably consist of, PTFE.

[0037] The endoprosthesis and methods described herein are particularly suitable for use in combination with the endoprosthesis disclosed in WO 2013 / 182614 A1, the contents of which are incorporated herein by reference. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Hereinafter, the present invention is described in detail with reference to the following drawings:

[0039] Figure 1 : Schematically shows an endoprosthesis according to the present invention.

[0040] Figure 2a-2b : Shows a top view of the support strip and a side view when attached to the endoprosthesis.

[0041] Figure 3a-3b : Shows another support strip in top view and in side view when attached to an endoprosthesis.

[0042] Figure 4a-4b : Different embodiments of fiber attachment are shown.

[0043] Figure 5 : Schematically illustrates the method according to the present invention.

[0044] Figure 6 : Detailed illustration of the endoprosthesis is shown. DETAILED DESCRIPTION

[0045] Figure 1 An endoprosthesis 1 according to the invention is schematically shown, comprising a body portion 2 and a first facing 4. A plurality of fibers 5 are attached to the first facing 4 by means of support strips (not shown) and fixing strips 7. The support strips and fixing strips are elongated and extend in the direction of the longitudinal axis L of the endoprosthesis 1.

[0046] Figure 2a Schematically shown is a support strip 6 with a plurality of fibers 5 attached thereto. The support strip comprises polyurethane as an adhesive component. In this particular embodiment, the support strip has an elongated shape and the fibers extend only on one side of the support strip.

[0047] Figure 2b The fixing layer 7 is shown in cross-section. Figure 2a Because the fibers 5 are attached to only one side of the support strip 6, the fibers 5 also extend only on one side of the fixing layer 7.

[0048] Figure 3a There is shown an alternative embodiment of a support strip 6. This support strip 6 presents an elongated shape with fibers 5 extending from both sides.

[0049] Figure 3b The diagram shows the structure of the first surface layer 4 when fixed to the first surface layer 4 by means of the fixing layer 7. Figure 3a The fibers 5 extend from the fixing layer 7 on both sides in a manner corresponding to the fiber arrangement of the supporting strips.

[0050] Figure 4aAn embodiment of the endoprosthesis is shown in side view. In this particular embodiment, no support strips are used. Instead, the fibers 5 are placed directly onto the first facing layer 4. The fixing layer is placed over the first ends 9 of the fibers 5, while the second ends 10 of the fibers 5 extend from the fixing layer 7.

[0051] Figure 4b An alternative embodiment of the endoprosthesis is shown. In this particular embodiment, no support strips are used. Instead, the fibers 5 are placed directly onto the first facing layer 4. The middle portion 11 of the fibers 5 is placed between the first facing layer 4 and the fixing layer 7. The first and second ends 9, 10 of the fibers 5 extend away from the fixing layer.

[0052] Figure 5 The steps of the method according to the present invention are schematically shown. In a first step (A), an endoprosthesis is provided. For the sake of simplicity, only the first surface layer 4 is shown. Here, the first surface layer consists of electrostatically spun polytetrafluoroethylene (PTFE) fibers. In another step (B), a support strip 6 with fibers 5 attached to both sides thereof is provided and arranged to the first surface layer 4. Another step (C) includes arranging a protective strip 8 to the first surface layer 4 and the fibers 5. The fibers 5 are tightly held to the surface of the first surface layer 4 and are completely covered by the protective strip 8. The support strip 6 is not covered by the protective strip 8. In the next step (D), the endoprosthesis is provided with a fixing layer (7). Here, the fixing layer 7 consists of a pre-cut piece of electrostatically spun PTFE fiber with an adhesive layer 7a of polyurethane. The fixing layer 7 is arranged to the support strip 6. The side of the fixing layer 7 with the adhesive layer 7a is oriented towards the support strip 6 and the first surface layer 4. Finally (E), the protective strip 8 is removed. This releases the fibers 5, which now extend freely from the support strip 6 and the fixing layer 7. At this point, a heating and pressure step is used to press the fixing layer 7 toward the first facing layer 4 and locally melt the adhesive layer of the fixing layer 7, which penetrates the support strip 6, the first facing layer 4, and the fixing layer 7 to enhance the fixation. Because of the melting and penetration of the other layers, the adhesive layer 7a is no longer visible after this step.

[0053] Figure 6 A specific embodiment of an endoprosthesis is shown. This illustration corresponds to Figure 5Step E in . Here, the endoprosthesis frame comprises a metal stent 3 arranged in a first surface layer. In this particular embodiment, the endoprosthesis has several body elements 2, 13a, 13b, of which two body elements 13a and 13b have a diameter smaller than the other main body part 2. The endoprosthesis 1 has a Y-shape. The stent 3 consists of an interconnected grid made of Nitinol shape memory alloy. It is encapsulated by electrospun PTFE fibers constituting the first surface layer. Fibers 5 are provided to the support strips 6 arranged to the first surface layer 4. After coating with another layer of electrospun PTFE fibers and removing the protective strip (not shown here), the support strips 6 are encapsulated in a sandwich structure between the first surface layer 4 and the fixing layer 7. The total thickness T of the endoprosthesis wall 7 including the first surface layer 4, the stent 3, the support strips 6 and the fixing layer 7 is between 115 microns and 120 microns.

Claims

1. An endoprosthesis (1) having a longitudinal axis (L), comprising: - at least one body portion (2), a first surface layer (4) and a support arranged in the first surface layer; - at least one thrombogenic fiber (5); It is characterized by: The endoprosthesis (1) further comprises at least one sheet-like fixing layer (7) attaching the at least one thrombogenic fiber (5) to the endoprosthesis (1), wherein - said at least one thrombogenic fiber (5), and - a support structure for the thrombogenic fibers (5) At least one of them is at least partially arranged between the sheet-like fixing layer (7) and the first surface layer (4).

2. The endoprosthesis (1) according to claim 1, wherein the at least one thrombogenic fiber (5) has at least one portion extending from the sheet-like fixing layer (7) and the first surface layer (4).

3. The endoprosthesis (1) according to one of claims 1 or 2, further comprising a support structure, the support structure being at least one support strip (6), wherein the at least one thrombogenic fiber (5) is attached to the at least one support strip (6).

4. Endoprosthesis (1) according to claim 3, wherein the at least one supporting strip (6) is arranged between the first surface layer (4) and the at least one sheet-like fixing layer (7).

5. Endoprosthesis (1) according to claim 3, wherein at least one of the support strip (6) and the sheet-like fixing layer (7) comprises an adhesive.

6. Endoprosthesis (1) according to claim 5, wherein the adhesive is adapted to penetrate, in its molten state, into at least one of the first facing layer and the sheet-like fixing layer (7).

7. The endoprosthesis (1) according to claim 5, wherein the adhesive is provided as an adhesive layer (7a) on the sheet-like fixing layer (7).

8. Endoprosthesis (1) according to claim 1, wherein at least one of the first facing layer (4) and the at least one sheet-like fixing layer (7) comprises polytetrafluoroethylene.

9. Endoprosthesis (1) according to claim 1, wherein the first surface layer (4) and the at least one sheet-like fixing layer (7) consist of the same material.

10. The endoprosthesis (1) according to claim 1, wherein the at least one sheet-like fixing layer (7) is arranged so that the first end (9) and the second end (10) of the at least one thrombogenic fiber (5) extend from the sheet-like fixing layer (7) and the first surface layer (4).

11. The endoprosthesis (1) according to claim 1, wherein the first end (9) of the at least one thrombogenic fiber (5) is arranged between the sheet-like fixing layer (7) and the first surface layer (4), and the second end (10) of the at least one thrombogenic fiber (5) extends from the sheet-like fixing layer (7) and the first surface layer (4).

12. The endoprosthesis (1) according to claim 1, comprising at least two sheet-like fixing layers (7), wherein at least two of the sheet-like fixing layers are separated by a gap along the surface of the first surface layer (4).

13. Endoprosthesis (1) according to claim 1, wherein the at least one sheet-like fixing layer (7) has an elongated shape extending in a direction parallel to the longitudinal axis (L) of the endoprosthesis (1).

14. A method of manufacturing an endoprosthesis (1) according to any one of the preceding claims, comprising the steps of: - providing an endoprosthesis frame comprising a first facing (4) and a stent arranged within said first facing; - providing at least one thrombogenic fiber (5); - providing at least one sheet-like fixing layer (7); - arranging the at least one thrombogenic fiber (5) to the first facing (4); - attaching the thrombogenic fiber (5) to the first surface layer (4) by fixing the sheet-like fixing layer (7) to the first surface layer (4), wherein the at least one thrombogenic fiber (5) and the support structure for the thrombogenic fiber are at least partially arranged between the sheet-like fixing layer (7) and the first surface layer (4).

15. Method according to claim 14, wherein a support structure is provided, said support structure being at least one support strip (6) with at least one said thrombogenic fiber (5) attached thereto.

16. Method according to claim 15, wherein at least one of the at least one supporting strip (6) and the at least one sheet-like fixing layer comprises an adhesive, and the step of fixing the sheet-like fixing layer (7) comprises activating the adhesive.

17. Method according to any one of claims 14 to 16, further comprising the step of providing at least one protective strip (8) releasably attached to the endoprosthesis (1), wherein In its attached state, the protective strip (8) holds the at least one thrombogenic fiber (5) to the surface of the first facing layer (4).

Images