STENT GRAFT AND METHOD FOR PRODUCING SAME

Abstract

The invention relates to a method for producing a stent graft. The method comprises providing a graft made of a first polymer-based material and applying a stent structure comprising a plurality of struts made of a second polymer-based material onto the graft by means of an additive manufacturing method. The invention further relates to a stent graft produced by means of the method.

Claims

1. A method for producing a stent graft, which comprises the following steps: providing a graft made of a first polymer-based material; and applying a stent structure comprising a plurality of struts made of a second polymer-based material onto the graft by means of an additive method; wherein the graft and the applied stent structure are configured such that the stent graft is arrangeable in at least one compressed state and in at least one expanded state, wherein the stent graft has a smaller cross-section in the at least one compressed state than in the at least one expanded state.

2. The method according to claim 1, wherein the graft is tubular and/or tube-shaped.

3. The method according to claim 1, wherein the produced stent graft is configured such that the graft is arranged within the stent structure.

4. The method according to claim 1, wherein the graft is textile and/or textile-based.

5. The method according to claim 1, wherein the graft is produced by means of a jacquard technique.

6. The method according to claim 1, wherein the stent structure comprises a smart polymer, in particular a shape memory polymer.

7. The method according to claim 1, wherein the provided graft comprises fenestrations.

8. The method according to claim 1, wherein the provided graft comprises a plurality of pores formed by a textile structure of the graft and having a diameter of 1 to 1,000 μm.

9. The method according to claim 8, wherein individual pores have an opening area of 1 to 1,000,000 μm.sup.2.

10. The method according to claim 1, wherein the struts, in a cross-section perpendicular to the direction in which the respective strut extends, have a height of at least 10 μm in the radial direction of the stent graft and/or a width perpendicular to the height of at least 10 μm, in the cross-section.

11. The method according to claim 1, wherein the struts, in a cross-section perpendicular to the direction in which the respective strut extends, in the radial direction of the stent graft, are made from a plurality of layers, and/or wherein the struts, in a cross-section perpendicular to the direction in which the respective strut extends, perpendicular to the radial direction of the stent graft, comprise a plurality of layers.

12. The method according to any claim 1, which further comprises the steps of: obtaining preoperative medical image data of a vessel; and generating a computer-aided model of the graft, the stent structure and/or the stent graft by means of the image data.

13. The method according to claim 1, wherein the stent structure is applied onto the graft by using a rotatable holder by means of which the graft can be held and rotated.

14. The method according to claim 1, wherein the struts configure a compressible helical, zigzag or mesh structure and/or meander-shaped rings.

15. The method according to claim 1 wherein the graft comprises one or more scallops.

16. The method according to claim 1, wherein the graft has a material layer thickness of 0.01 mm to 2 mm after its production.

17. The method according to claim 1, wherein the provided graft is configured to be permeable to liquid and wherein the graft forms a self-sealing system.

18. The method according to claim 1, wherein the provided graft is impermeable to liquid.

19. The method according to claim 18, wherein the provided graft is impermeable to liquid by means of a coating, wherein the method comprises a step of coating the graft before the application of a stent structure onto the graft.

20. The method according to claim 18, wherein the provided graft is impermeable to liquid by means of a coating, wherein, after the application of a stent structure onto the graft, the method comprises a step of coating the produced stent graft.

21. The method according to claim 1, wherein the stent graft comprises at least one stent structure that is arranged on the graft at least partially inside and outside, and/or wherein the stent graft comprises at least one stent structure that is arranged on an inner side of the graft and at least one stent structure that is arranged on an outer side of the graft.

22. The method according to claim 1, wherein the stent graft is metal-free.

23. A stent graft, produced according to the method of claim 1.

24. The stent graft of claim 23, wherein the stent structure surrounds the graft.

25. The method according to claim 1, wherein the additive method is fused deposition modeling.

26. The method according to claim 4, wherein the graft is a weave and/or knitwear.

27. The method according to claim 7, wherein the fenestrations have a diameter between 3 mm and 12 mm.

Description

[0066] FIG. 1 shows a schematic flow chart of a method according to the invention;

[0067] FIG. 2 shows a schematic illustration of the application of the stent structure onto a graft according to the invention;

[0068] FIG. 3 shows a schematic illustration of the stent graft according to the invention in a compressed and an expanded state.

[0069] FIG. 1 is a schematic flowchart illustrating the steps of a method 100 according to the invention for producing a stent graft 1 (see also FIG. 2), wherein dotted lines indicate optional steps. In a preferred embodiment of the method, preoperative medical image data of a vessel are first provided (step 110), which were gathered, for example, in the course of a computed and/or magnetic resonance tomography. The image data may be processed in a manner known to the person skilled in the art in order to obtain a 3-dimensional resolution as high as possible and may be used to generate a computer-aided model of the graft 10, the stent structure 20 and/or the stent graft 1 (step 120). The production of the stent graft 1 according to the invention, which is preferably customized, is accomplished by providing (step 130) a preferably polymer-based graft 10 onto which a stent structure 20 comprising a plurality of struts made of a preferably polymer-based material is applied (step 140). This is preferably done by means of fused deposition modeling as an additive manufacturing process. The stent graft 1 according to the invention may be optionally inverted (step 150) after the stent structure has been applied in step 140, for example, in order to arrange the stent structure 20 within the graft 10.

[0070] FIG. 2 is a perspective view schematically illustrating a production of the preferably tubular and/or tube-shaped, in particular hollow-cylindrical stent graft 1, which preferably extends from a first open end 11 to an opposite, second open end 12. The graft 10 preferably being textile-based or consisting of textile may be slid onto and/or rest on a holder (not shown). The holder may be rotatably mounted, for example such that the graft 10 may be rotated around its longitudinal axis A. The geometry of the holder may be selected according to the geometry of the graft 10, in particular, the outer diameter of a cylindrical holder may be selected according to the vessel diameter to be treated.

[0071] The tubular graft 10 exemplarily shown in this Figure comprises two fenestrations 14, which are shown here in the area of the second end 12. However, these fenestrations may also be provided at other locations of the graft along the longitudinal axis A (e.g., in the middle). Additionally and/or alternatively, the graft 10 could also comprise at least one scallop, further fenestrations and/or branches, so-called branch stents (“branches”), along the longitudinal axis A. In addition and/or alternatively, the graft 10 may also comprise further openings at the ends 11, 12 or it could be bifurcated (“bifurcation”, not shown) at one of these ends 11, 12.

[0072] The stent structure 20 is preferably applied directly onto the graft 10 in that polymer-based or polymeric material provided therefor is heated in a heatable nozzle head 70 and one or more liquefied filaments are applied 140 onto the graft 10 in one or more layers. This may be done, for example, in an automated method according to a computer-aided model of the stent graft 1 generated in step 120, while the nozzle head 70 moves essentially along the longitudinal direction of the graft 10 (see arrow 71) and the holder rotates as needed. Alternatively, the holder may also be moved essentially in the longitudinal direction or the holder and the nozzle head 70. The thus formed plurality of interconnected struts of the stent structure 20 may optionally be arranged as rings, zigzag, helix, spirals, meshes and/or other geometry, wherein, for example, individual segments of the stent structure may be directly or indirectly connected to each other via connectors.

[0073] The stent graft 10 may be inserted into a vessel in a known manner. FIG. 3 shows a schematic overview of various states that the stent graft may at least exhibit, with the change in state being preferably reversible and rapid due to the material and/or material combination of the stent structure. During its production, the stent graft may initially exhibit a first state (FIG. 3A). For example, the stent graft may be produced in an expanded state.

[0074] After its production, but at the latest before its insertion into the affected vessel, preferably endovascular and/or minimally invasive, the stent graft exhibits a compressed, crimped state (FIG. 3B). For this purpose, depending on the stent geometry, for example, the opening angle between two struts connected at a junction and/or intersection point may be reduced. After the stent graft has been positioned in the affected portion of the vessel, it is transformed into an expanded state, in which it has a larger diameter than in the at least one crimped state (FIG. 3C), wherein the expanded state may optionally correspond to the first state. This change in state may be caused by the application of a mechanical force or in a predefined way by the change of an external factor if a respective smart polymer was used to form the stent structure (e.g., by returning to an expanded shape when the temperature is increased). In this case, the expanded state is preferably achieved by reaching the body temperature and thus a temperature of 37° C.

[0075] In the expanded state, the stent structure preferentially exhibits a radial stiffness that is sufficient to bridge or replace the affected portion of the vessel. The graft is preferably configured as a self-sealing system that is initially permeable to liquid and, upon implantation of the stent graft, seals itself within a short time by coagulation of components contained in the liquid transported in the vessel and/or their deposition in and/or on the graft.

[0076] As far as the above description uses the expression “essentially” or corresponding terms, embodiments in which the respective feature is fully or completely present are also comprised. The words “plurality” or “several” are to be understood in the sense of “at least two”, i.e., two or more. If specific values are indicated, these values preferably also comprise minor deviations from these values, such as, for example, deviations of +/−10% or +/−5% of the respective value. Individual aspects of the invention may constitute independent inventions and may also be claimed as such.