EP4251099A1

EP4251099A1 - Stent

Info

Publication number: EP4251099A1
Application number: EP21815151.2A
Authority: EP
Inventors: Andreas Ding; Andrés BRASCHKAT; Andreas SCHÜSSLER
Original assignee: Acandis GmbH and Co KG
Current assignee: Acandis GmbH and Co KG
Priority date: 2020-11-26
Filing date: 2021-11-16
Publication date: 2023-10-04
Also published as: US20240000589A1; DE202020106808U1; DE102021117096A1; WO2022112052A1

Abstract

Stent comprising a mesh (10) consisting of wires (11), each having a radiopaque core material and a superelastic shell material and defines loops (14) at a first stent end (12) and open wire ends (15) at a second stent end (13), wherein: the number of wire ends (15) is double the number of loops (14); more than 10 vol.%, in particular more than 20 vol.%, more particularly at least 25 vol.%, in particular at least 30 vol.% of each wire (11) is constituted by the core material; the mesh (10) comprises - 48 wires (11), each having a wire diameter of 0.038 mm and an outer diameter of 3.65 mm or 4.15 mm or 4.65 mm; or - 52 wires (11) each having a wire diameter of 0.042 mm and an outer diameter of 5.17 mm or 5.67 mm or 6.17 mm; or - 64 wires (11) each having a wire diameter of 0.046 mm or 0.05 mm and an outer diameter of 7.18 mm or 8.20 mm.

Description

stent

DESCRIPTION

The invention relates to a stent with a mesh of wires. Such stents are known from practice. It is also known to provide at least some of the wires with a radiopaque core material and a superelastic sheath material so that the stent or braid is visible under X-ray control. Furthermore, stents are known which have loops at least at one end of the stent and are thus effective atraumatically, i.e. reduce the risk of injury from the implantation of the stent.

Previously known stents usually comprise wires with a core material content of at most 20% by volume. These known stents are visible under X-ray control. However, there is a desire for improved visibility of stents under X-ray control.

For example, DE 10 2015 107 291 A1 describes a stent with wires that have an X-ray-visible core wire, the cross-sectional area of the core wire having a proportion of at most 20% based on the total cross-sectional area of the wire.

DE 10 2018 133 345 A1 discloses a stent that is braided from a single wire that has an X-ray-visible core material with a core material content of 27%. Because of its single-wire construction, the well-known stent is characterized by a special radial force, which, however, is not desired for all applications.

DE 10 2019 104 827 A1 discloses a stent which, due to a special surface treatment, has a particularly low tendency to release nickel and therefore offers improved biocompatibility.

DE 10 2019 104 828 A1 deals with a stent that is formed from wires that have an X-ray-visible core material. By a predetermined ratio between the cross-sectional area of the core material based on the Due to the overall cross-sectional area of the wire, good visibility under X-ray control is achieved with this stent. The present invention further develops this stent in order to open up further fields of application.

The invention is therefore based on the object of specifying a stent with a mesh of wires which has improved X-ray visibility.

According to the invention, this object is achieved by the subject matter of claim 1.

The invention is based on the idea of specifying a stent with a braiding of wires, each of which has an X-ray-visible core material and a super-elastic jacket material. The wires form loops at a first end of the stent and open wire ends at a second end of the stent. The number of wire ends is twice the number of loops.

According to the invention, more than 10% by volume, in particular more than 20% by volume, in particular at least 25% by volume, in particular at least 30% by volume, of each wire is formed by the core material.

By increasing the proportion of core material, the X-ray visibility of the stent is significantly increased.

A further improvement in X-ray visibility is achieved by increasing the number and diameter of wires. Thus, the invention provides that the mesh has 48 wires, each with a wire diameter of 0.038 mm. In this variant, it is preferred if the outside diameter of the braid is 3.65 mm or 4.15 mm or 4.65 mm.

A further variant of the stent according to the invention provides that the mesh has 52 wires, each with a wire diameter of 0.042 mm. In this variant, the outside diameter is preferably 5.17 mm or 5.67 mm or 6.17 mm.

The stent alternatively comprises a braid with 64 wires, the wires each having a wire diameter of 0.046 mm or 0.05 mm. The outer diameter of the mesh in this variant of the invention is preferably 7.18 mm or 8.20 mm. According to the invention, a braid with an outer diameter of 7.18 mm has 64 wires, each of which has a wire diameter of 0.046 mm. On the other hand, a braid with an outer diameter of 8.20 mm comprises 64 wires with a wire diameter of 0.05 mm.

A tolerance of ±0.2 mm must be taken into account for all of the aforementioned outside diameter values. A tolerance of ±0.003 mm applies to the aforementioned wire diameters. Furthermore, it applies to all embodiments that all wires of the mesh or stent have a core material and a jacket material.

In a further variant of the invention it is provided that the mesh has a cylindrical section and a conical section. The conical section can, in particular exclusively, form the first end of the stent. Preferably, the conical section has a different braiding angle than the cylindrical section. The braid angle is the angle that the respective wires assume in relation to the longitudinal axis of the stent. Preferably, wires wound in different spiral directions and crossing or crossing each other have identical braiding angles.

In a preferred variant, a first braiding angle in the cylindrical section can be 75° and/or a second braiding angle in the conical section is 60°. A transition section can be provided between the cylindrical section and the conical section, which has a smaller, preferably third, braiding angle and/or a higher porosity than the cylindrical section. The first braiding angle preferably has a tolerance of ±2° and/or the second braiding angle has a tolerance of ±4°. The, in particular third, braiding angle in the transition section can have a tolerance of ±3°.

The length of the braid is preferably between 12mm and 38mm. Specifically, the braid may be any of the following lengths: 12mm, 13mm, 15mm, 16mm, 19mm, 20mm, 22mm, 23mm, 24mm, 28mm, 30mm, 31mm, 37mm, 38 mm. The first end of the stent can have a length of 4 mm. The first end of the stent designates the area in which the loops are formed. The distance from the tip of the loop to the first crossing of two wires is measured to determine the length. This area is referred to as the first end of the stent and preferably has a length of 4 mm.

All length values can have a tolerance of ±1 mm.

In order to achieve good feedability via a catheter and good biocompatibility, it is preferred if the mesh, in particular the wires, have a blue shimmering oxide surface. The oxide surface facilitates delivery through a catheter and improves biocompatibility. The shimmering blue appearance makes it easier for users of the stent to distinguish it from other stents.

The oxide surface preferably comprises or consists of a mixed oxide layer. The mixed oxide layer can include titanium oxynitride. The layer thickness of the mixed oxide layer is preferably between 150 nm and 400 nm, in particular between 200 nm and 350 nm, in particular between 250 nm and 300 nm.

Because of the improved x-ray visibility through the use of the wires with an x-ray-visible core material, it is provided in particularly preferred embodiments that the mesh does not have any additional x-ray markers. The braid can consist solely of the wires. This means that there are no additional elements that protrude beyond the diameter of the wire and can thus make it difficult to feed or compress the braid. In other words, the mesh or the stent is easily compressible and can be inserted into a blood vessel through a catheter. Even in the implanted state, the risk of tissue irritation due to elements penetrating the tissue and protruding beyond the stent surface, such as additional X-ray markers, is thus avoided. In a preferred variant, the stent consists of the mesh. In other words, the stent preferably has no other components than the mesh.

In an alternative configuration of the stent, on the other hand, it is provided that the stent has the mesh and at least one, preferably three, x-ray markers. The X-ray marker or the X-ray markers are preferably arranged in the loops at the first end of the stent. In particular, the X-ray marker or the X-ray markers can be formed by a sleeve which is crimped onto the wire at the loops. It is advantageous if the stent in this variant only has the mesh and one or more X-ray markers, preferably on the loops.

It also applies to all embodiments that the core material of the wire is preferably platinum. It is also conceivable to use a platinum alloy, in particular a platinum-iridium alloy, as the core material. The cladding material is preferably a nickel-titanium alloy. The nickel-titanium alloy has shape memory properties or superelastic properties. As a result, the stent is self-expanding.

The invention is explained in more detail below using an exemplary embodiment with reference to the accompanying schematic drawing. The only figure therein shows a perspective view of a stent according to the invention.

The stent consists of a braid 10 which is formed from a number of wires 11 . The braid has a first end 12 and a second end 13 of the stent. Loops are formed at the first end 12 of the stent. The wires 11 are thus deflected and guided back at the first end 12 of the stent, so that the loops 14 are formed. In particular, it can be seen that every second loop 14 is set back in relation to the adjacent loop 14 . Protruding loops 14a and recessed loops 14b are therefore provided.

The offset arrangement of the loops 14a, 14b facilitates the compressibility of the first stent end 12. The first stent end 12 is preferably flared. The loops 14, in particular the protruding loop 14a, therefore point outwards with their tip. This design improved the anchoring of the first end of the stent 12 when implanted. Open wire ends 15 can be seen at the second stent end 13 of the braiding 10 . The wires 11 thus end at the second end of the stent 13.

Overall, the lattice structure comprises 48, 52 or 64 wires 11, which each form 24 or 26 or 32 loops 14. 12 or 13 or 16 loops 14 are designed as protruding loops 14a or set-back loops 14b. The stent is preferably offered in different dimensions. The table below shows an overview of the preferred embodiments of the stent.

reference list

10 braid

11 wire

12 first end of stent 13 second end of stent

14 loop

14a protruding loop

14b recessed loop

15 open wire end 16 cylindrical section

17 conical section

Claims

EXPECTATIONS

1. Stent with a mesh (10) of wires (11), each having an X-ray visible core material and a superelastic sheath material and loops (14) at a first stent end (12) and open wire ends (15) at a second stent end (13) form, the number of wire ends (15) being twice the number of loops (14) and more than 10% by volume, in particular more than 20% by volume, in particular at least 25% by volume, in particular at least 30% by volume, each wire (11) is formed by the core material, and the braid (10)

- 48 wires (11) each having a wire diameter of 0.038 mm and an outer diameter of 3.65 mm or 4.15 mm or 4.65 mm; or

- 52 wires (11) each having a wire diameter of 0.042 mm and an outside diameter of 5.17 mm or 5.67 mm or 6.17 mm; or

- 64 wires (11) each having a wire diameter of 0.046 mm or 0.05 mm and an outside diameter of 7.18 mm or 8.20 mm; having.

2. The stent of claim 1, characterized in that the outside diameter has a tolerance of ±0.2 mm.

3. The stent of claim 1 or 2, characterized in that the mesh (10) has a cylindrical section (16) and a conical section (17), the conical section (17) supporting the first stent end (12) forms and has a different braiding angle than the cylindrical section (16).

4. The stent of claim 3, dad u rch geken nzeich net that a first braiding angle in the cylindrical section (16) is 75° and/or a second braiding angle in the conical section (17) is 60°.

5. The stent as claimed in claim 3 or 4, characterized in that a transition section is provided between the cylindrical section (16) and the conical section (17) which has a smaller braiding angle and/or a higher porosity than the cylindrical section (16).

6. The stent according to claim 4 or 5, characterized in that the first braiding angle has a tolerance of ±2° and/or the second braiding angle has a tolerance of ±4°.

7. The stent as claimed in claim 1, characterized in that the mesh (10) has a length of between 12 mm and 38 mm.

8. The stent according to any one of the preceding claims, characterized in that the mesh (10) has one of the following lengths: 12 mm, 13 mm, 15 mm, 16 mm, 19 mm, 20 mm, 22 mm, 23 mm, 24mm, 28mm, 30mm, 31mm, 37mm, 38mm.

9. The stent as claimed in claim 1, characterized in that the first end of the stent (12) has a length of 4 mm.

10. The stent according to any one of claims 7 to 9, characterized in that the length has a tolerance of ±1 mm.

11. The stent as claimed in claim 1, characterized in that the mesh (10), in particular the wires (11), has a shimmering blue color have oxide surface.

12. The stent of claim 11, dad u rch geken nzeich net that the oxide surface is formed by a mixed oxide layer which

Includes titanium oxynitride and has a layer thickness of between 150 nm and 400 nm, in particular between 200 nm and 350 nm, in particular between 250 nm and 300 nm.

13. The stent as claimed in one of the preceding claims, characterized in that the mesh (10) has no additional X-ray markers and/or consists exclusively of the wires (11).

14. Stent according to any one of the preceding claims consisting of the

braid (10).