A vascular stent

Abstract

The present invention discloses a vascular stent, comprising a stent body, wherein the stent body is a mesh tube structure woven from metal wires, wherein the stent body comprises a first stent segment and a second stent segment connected in the axial direction, and the mesh density of the first stent segment is different from the mesh density of the second stent segment. The vascular stent provided by the present invention has a bare segment to improve the treatment effect for the stenosis of the inferior vena cava and iliofemoral vein, a dense mesh structure with a large mesh density for the compressed part to improve the support strength and anti-extrusion performance, and a sparse mesh structure with a small mesh density for the curved part to increase the compliance and wall adhesion performance; a variable diameter structure can conform to the vascular morphology according to the anatomical morphology of the blood vessel, and is suitable for various blood vessel diameters.

Description

Technical Field

[0001] The present invention relates to the field of vascular interventional medicine, and in particular to a vascular stent. Background Art

[0002] Venous diseases are currently the most common diseases in vascular surgery, especially iliac vein compression syndrome, which refers to a syndrome in which iliac artery compression leads to intraluminal adhesion, stenosis or occlusion, resulting in various clinical symptoms. The incidence of iliac vein compression syndrome is 20%-40%.

[0003] In recent years, interventional therapy has been used as a routine procedure for treating venous compression. Currently, there are two types of stents on the market for treating venous stenosis: cutting stents and braided stents. Cutting stents can support the narrowed and occluded segments of the blood vessels, reduce the elastic retraction of the blood vessels, and maintain smooth blood flow in the lumen, but they also have some shortcomings, such as insufficient flexibility and easy breakage. Braided stents are mesh structures made of one or more wires. Braided stents have attracted more and more attention due to their advantages such as good flexibility, strong support and good wall adhesion. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a vascular stent which has both strong supporting strength and excellent flexibility.

[0005] The technical solution adopted by the present invention to solve the above-mentioned technical problems is to provide a vascular stent, including a stent body, which is a mesh tube structure woven from metal wires, wherein the stent body includes a first stent segment and a second stent segment connected in the axial direction, and the mesh density of the first stent segment is different from the mesh density of the second stent segment.

[0006] Furthermore, the stent body is a variable diameter structure in the axial direction, and the proximal diameter D1 of the stent body is greater than the distal diameter D2 thereof.

[0007] Furthermore, the proximal diameter D1 of the stent body is 8-22 mm, and the distal diameter D2 of the stent body is 6-20 mm.

[0008] Furthermore, the mesh of the stent body is a diamond mesh, the side length A of the diamond mesh is 1-5 mm, and the angle β of the diamond mesh is 90°-160°.

[0009] Furthermore, the shorter of the two diagonal lines of the diamond mesh in the first stent segment is 1-4 mm in length, and the shorter of the two diagonal lines of the diamond mesh in the second stent segment is 2-6 mm in length.

[0010] Furthermore, the vascular stent also includes a first bare segment, which includes at least one first protrusion circumferentially formed by weaving metal wires, the distal end of the first bare segment is connected to the proximal end of the first stent segment, and the distal end of the first stent segment is connected to the proximal end of the second stent segment.

[0011] Furthermore, the proximal end of the first stent segment includes at least one third protrusion formed by weaving metal wires in the circumferential direction, and the apex of the first protrusion of the first bare segment and the apex of the third protrusion of the proximal end of the first stent segment are on the same axis.

[0012] Furthermore, the apex of the first protrusion at the proximal end of the first bare segment and the apex of the third protrusion at the proximal end of the first stent segment are distributed at equal intervals along the circumference of the vascular stent.

[0013] Furthermore, the length L3 of the first bare segment in the axial direction is 1-10 mm.

[0014] Furthermore, the number of first protrusions of the first bare segment is 1-10.

[0015] Furthermore, the vascular stent also includes a second bare segment, the second bare segment includes at least one second protrusion formed by weaving metal wires in the circumferential direction, and the proximal end of the second bare segment is connected to the distal end of the second stent segment.

[0016] Further, the first bare segment partially overlaps with the first stent segment in the axial direction, and the first bare segment partially extends beyond the first stent segment in the axial direction.

[0017] Furthermore, the angle between the extension direction of the first bare segment and the axial direction of the vascular stent is 0°-60°.

[0018] Furthermore, the mesh density of the first bare segment and the mesh density of the second bracket segment are both smaller than the mesh density of the first bracket segment.

[0019] Compared with the prior art, the present invention has the following beneficial effects: the vascular stent provided by the present invention comprises a first stent segment and a second stent segment with different mesh densities, and the mesh density of the stent body varies, which is conducive to the use of venous lesion areas at different positions. For example, for the iliac vein, the right iliac vein is compressed by the right iliac artery. The position here is located at the starting section of the right iliac vein, and high anti-extrusion performance is required. Therefore, the stent structure here can be a high-density mesh weaving structure, and the area that requires strong support strength and anti-extrusion performance according to the anatomical structure in the later stage can be a high-density mesh weaving. The mesh density can be different according to different requirements. The area with high bending performance can adopt a weaving structure with low mesh density. The larger mesh can increase its bending performance and flexibility to better fit the vascular morphology; and the stent body is set to a variable diameter structure to better conform to the vascular morphology. In particular, the first bare segment is set at the proximal end of the stent body, so that the overall stent can extend out of the iliac vein and extend into the inferior vena cava without affecting the contralateral venous blood flow, and can ensure the integrity of the stent after being placed in the vein. The second bare segment is set at the distal end to cross other venous branches to avoid affecting the blood flow of other branches. The venous vascular stent provided by the present invention can treat various venous diseases. For stenosis involving the inferior vena cava and iliofemoral vein, there are bare segments to improve the treatment effect. For the compressed parts, there are dense mesh structures to improve the support strength and anti-extrusion performance. For the curved parts, there are large-mesh sparse mesh structures to increase the flexibility and wall adhesion performance. For the anatomical morphology of the blood vessels, there are variable-diameter structures to conform to the vascular morphology and are suitable for various blood vessel diameters. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of the structure of a vascular stent in an embodiment of the present invention;

[0021] Figure 2 is a schematic diagram of the structure of a grid unit in an embodiment of the present invention;

[0022] Figure 3 is a schematic diagram of a compressed vein in an embodiment of the present invention;

[0023] Figure 4 This is a schematic diagram of the use state of the vascular stent after being implanted into a human body according to an embodiment of the present invention;

[0024] Figure 5 Schematic diagram of the local distribution of the first bare segment in an embodiment of the present invention.

[0025] In the figure:

[0026] 1 Vascular stent 2 Vein 3 Artery

[0027] 10 stent body 11 first stent segment 12 second stent segment

[0028] 13 first bare segment 131 first protrusion 14 grid unit DETAILED DESCRIPTION

[0029] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0030] In order to more clearly describe the structural features of the present invention, "proximal end" and "distal end" are used as directional words, wherein "proximal end" refers to the end close to the heart; "distal end" refers to the end far from the heart. The term "or" is usually used in the sense of including "and / or", unless the content clearly indicates otherwise.

[0031] See also Figure 1 and Figure 2 The vascular stent 1 provided in this embodiment includes a stent body 10. The stent body 10 is woven from metal wires into a mesh tube structure and has a plurality of grid units 14. The stent body 10 includes a first stent segment 11 and a second stent segment 12 connected in the axial direction. The proximal region of the stent body 10 is woven from metal wires into the first stent segment 11. The mesh size of the first stent segment 11 is smaller and the mesh density is larger. The distal region of the stent body 10 is woven from metal wires into the second stent segment 12. The mesh size of the second stent segment 12 is larger and the mesh density is smaller. The compressed part of the vein requires strong support strength. The mesh of the stent body 10 can be made denser to increase the support strength and local anti-extrusion performance. The uncompressed part and the cross-joint part require good flexibility. The mesh of the stent here can be made larger to increase its flexibility and wall adhesion. Specifically, Figure 1 In the figure, L2 is the first bracket segment 11, the mesh of this area is small, and the spacing H1 between the two opposite vertices of the grid unit in this area in the axial direction is preferably 1-4mm. L4 is the second bracket segment 12, the mesh of this area is large, and the spacing H2 between the two opposite vertices of the grid unit in this area in the axial direction is preferably 2-6mm.

[0032] The stent body 10 can be a variable diameter or a constant diameter structure in the axial direction, wherein the variable diameter stent is more in line with the venous anatomical structure and more suitable for the characteristics of venous blood vessels. It has a greater advantage for long-segment lesions, and the variable diameter stent can better conform to the vascular morphology. The constant diameter stent can be applicable to a small number of lesion areas. The lesion area is short and the diameter does not change much. The constant diameter stent can be applicable. In one embodiment, the stent body 10 is a variable diameter stent in the axial direction, and the proximal diameter D1 of the stent body 10 is preferably 8-22mm, and the distal diameter D2 of the stent body 10 is preferably 6-20mm. In order to better conform to the vascular morphology, preferably, the difference between the proximal diameter D1 and the distal diameter D2, that is, the variable diameter size can be 2mm or 4mm.

[0033] The metal wire of the braided vascular stent 1 can be memory alloy, stainless steel, titanium alloy, nickel alloy, cobalt-chromium alloy and biodegradable material; preferably, the stent body 10 is woven from NiTi (nickel titanium) wire, the wire diameter is between 0.1-0.5mm, and the entire vascular stent 1 can be woven from one metal wire or multiple metal wires. A single metal wire has fewer connection points; while multiple metal wires have good wall adhesion performance and high processing efficiency.

[0034] See also Figure 2 Preferably, the mesh unit 14 woven from the metal wire is a diamond mesh; the side length of the diamond mesh is A, and the diamond angle is β. These two parameters and the number of metal wires used in the stent body 10 affect each other. When the number of metal wires used in the stent body 10 is fixed, the shorter the side length A and the larger the angle β, the stronger the support strength / anti-extrusion ability of the manufactured stent, and the better the bending performance; the longer the side length A and the smaller the angle β, the weaker the support strength / anti-extrusion ability of the stent, and the poorer the bending performance. When the side length A is fixed, the more wires used in the stent, the smaller the angle β, the weaker the support strength / anti-extrusion ability of the stent, and the poorer the bending performance; on the contrary, the fewer the number of metal wires, the larger the angle β, the stronger the support strength / anti-extrusion ability of the stent, and the good bending performance; when the angle β is fixed, the more metal wires, the shorter the side length A, the stronger the support strength / anti-extrusion ability of the stent, and the good bending performance; on the contrary, the fewer the number of metal wires, the longer the side length A, the weaker the support strength / anti-extrusion ability of the stent, and the poorer the bending performance. According to tests, in addition to strong support strength and anti-extrusion ability, the venous stent also requires excellent bending and compliance. Therefore, in a preferred embodiment, the number of metal wires is preferably 8-32, the length of the side length A is between 1-5 mm, and the angle β is between 90°-160°. The three are matched to achieve a better implementation effect.

[0035] See also Figure 3 and Figure 4If the inferior vena cava disease is involved, the vascular stent 1 will be extended into the inferior vena cava 2. If the extension length is too long, it will affect the contralateral venous blood flow in the long term. If the stent segments are inserted too densely, it will also affect the contralateral venous blood flow and cause contralateral venous occlusion in the long term. Preferably, a first bare segment 13 is provided at the proximal end of the stent body 10. The first bare segment 13 includes at least one first protrusion 131 formed by braiding metal wire in the circumferential direction. The distal end of the first bare segment 13 is connected to the proximal end of the first stent segment 11. The distal end of the first stent segment 11 is connected to the proximal end of the second stent segment 12. In one embodiment, the first bare segment 13 partially overlaps with the first stent segment 11 in the axial direction, and the first bare segment 13 partially extends beyond the first stent segment 11 in the axial direction. The stent body 10 is provided with a second bare segment (not shown) at the distal end. The second bare segment includes at least one second protrusion (not shown) formed by braiding metal wire in the circumferential direction. The proximal end of the second bare segment is connected to the distal end of the second stent segment 12. The distal end of the first stent segment 11 is connected to the proximal end of the second stent segment 12. The proximal first bare segment 13 can effectively treat lesions involving the iliac-inferior space. The first bare segment 13 is not long and the number is small, so it will not affect the contralateral venous blood flow; the distal second bare segment can dilate the venous branches involved in the distal lesions without affecting the blood flow of other branches. Please refer to Figure 1 The length L3 of the first protrusion 131 in the axial direction is preferably 1-10 mm, the angle α formed between the extension direction of the first protrusion 131 and the axial direction of the stent body can be 0-60°, the number of the first protrusion 131 is controlled to be 1-10, and the relationship between the first bare segment 13 and the proximal vertex of the first stent segment 11 is as follows: Figure 5 As shown. There are several main structures:

[0036] The proximal end of the first stent segment includes at least one third protrusion formed by weaving metal wire in the circumferential direction. The apex of the first protrusion at the proximal end of the first bare segment 13 and the apex of the third protrusion at the proximal end of the first stent segment 11 can be on the same axis. This structure has strong applicability. The apex of the third protrusion at the proximal end of the first stent segment 11 can also be between the apex of the first protrusions at the proximal ends of two adjacent first bare segments 13. This structure has good wall adhesion. Preferably, the apex of the first protrusion at the proximal end of the first bare segment 13 and the apex of the third protrusion at the proximal end of the first stent segment 11 are evenly distributed along the circumference of the vascular stent 1. Because the venous anatomical structure is elliptical, the first bare segment 13 can also be designed as a variable height structure, an equal height structure or a spiral structure, etc., to adapt to different venous morphologies. Figure 5 Several structures shown can extend into the inferior vena cava, including Figure 5(a) The first bare segments 13 are separated structures. Specifically, the apex of the proximal end of the first stent segment 11 is between the apex of the proximal ends of two adjacent first bare segments 13, and the heights of the first protrusions 131 in the axial direction are the same. This structure can not only extend the vascular stent 1 into the inferior vena cava to ensure its vascular morphology, but also ensure the adhesion performance of the vascular stent 1 to the iliac vein; Figure 5 In (b) and (c), the vertex of the first protrusion at the proximal end of the first bare segment 13 and the vertex of the third protrusion at the proximal end of the first stent segment 11 are located on the same axis, and the vertices of each first protrusion 131 are at the same height in the axial direction. This structure can enable the vascular stent 1 to have good wall adhesion performance, strong support strength and anti-extrusion performance. Figure 5 In (d), the first bare segment 13 is a variable height structure. Specifically, the apex of the first protrusion 131 gradually increases in axial height. After the vascular stent 1 with this structure is implanted in the inferior vena cava, the short first protrusion 131 can be located at the bifurcation of the inferior vena cava, and the long first protrusion 131 can be located at the straight section of the inferior vena cava, which is beneficial to the patency of the contralateral venous blood flow. The first bare segment 13 can be woven into different structures according to needs. In addition to the proximal first bare segment 13, a second bare segment can be added at the distal end to avoid affecting the blood flow of other branches. The structure, quantity, and shape of the second bare segment are similar to those of the first bare segment 13, and different structures can be woven according to needs.

[0037] The mesh density of the vascular stent 1 provided by the present invention varies, which is conducive to being used in venous lesion areas at different locations. For example, for the iliac vein, the right iliac vein is compressed by the right iliac stent body. The position here is located at the starting section of the right iliac vein, and high anti-extrusion performance is required. Therefore, the stent structure here can be a high-density mesh weaving structure, and the area that requires strong support strength and anti-extrusion performance according to the anatomical structure in the later stage can be a high-density weaving. According to different clinical needs, the degree of change of the mesh density can be different. The area with high bending performance can adopt a weaving structure with low mesh density. The mesh becomes larger and its bending performance and flexibility can be more in line with the vascular morphology. It can also be set as a variable diameter stent to better conform to the vascular morphology. In particular, the first bare section 13 is provided at the proximal end of the stent body 10, which can make the overall stent extend out of the iliac vein and extend into the inferior vena cava without affecting the contralateral venous blood flow, and can ensure the integrity of the stent after being placed in the vein. The second bare section is provided at the distal end to cross other venous branches to avoid affecting the blood flow of other branches. The venous vascular stent provided by the present invention can treat various venous diseases. For stenosis involving the inferior vena cava and iliofemoral vein, there is a bare segment to improve the treatment effect. For the compressed area, there is a first stent segment 11 to improve the support strength and anti-extrusion performance. For the curved area, there is a large-mesh second stent segment 12 to increase the flexibility and wall adhesion performance. For the anatomical morphology of the blood vessels, there is a variable diameter structure to conform to the vascular morphology and is suitable for various blood vessel diameters.

[0038] Although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art may make some modifications and improvements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be based on the definition of the claims.

Claims

1. A vascular stent for use in the inferior vena cava and iliofemoral vein, comprising a stent body and a first bare segment, wherein the stent body is a mesh tube structure woven from metal wires, characterized in that: The stent body includes a first stent segment and a second stent segment connected in the axial direction, the mesh density of the first stent segment is different from the mesh density of the second stent segment, the distal end of the first stent segment is connected to the proximal end of the second stent segment, and the distal end of the first bare segment is connected to the proximal end of the first stent segment; The first bare segment comprises at least one first protrusion formed by weaving metal wires in the circumferential direction, and the first bare segment is a variable height structure, a constant height structure or a spiral structure in the circumferential direction; The proximal end of the first stent segment includes at least one third protrusion formed by braiding metal wires in the circumferential direction, and the apex of the first protrusion of the first bare segment and the apex of the third protrusion of the proximal end of the first stent segment are on the same axis or are distributed at equal intervals along the circumference of the blood vessel stent; The mesh density of the first bare segment and the mesh density of the second bracket segment are both smaller than the mesh density of the first bracket segment; The stent body is a variable diameter structure in the axial direction, the proximal diameter D1 of the stent body is 8-22 mm, and the distal diameter D2 of the stent body is 6-20 mm; The number of metal wires of the stent body is 8-32, the mesh of the stent body is a diamond mesh, the side length A of the diamond mesh is 1-5 mm, and the angle β of the diamond mesh is 90°-160°; The shorter of the two diagonal lines of the diamond mesh in the first stent segment is 1-4 mm in length, and the shorter of the two diagonal lines of the diamond mesh in the second stent segment is 2-6 mm in length.

2. The vascular stent according to claim 1, characterized in that: The length L3 of the first bare segment in the axial direction is 1-10 mm.

3. The vascular stent according to claim 1, characterized in that: The number of first protrusions of the first bare segment is 1-10.

4. The vascular stent according to claim 1, characterized in that: The first bare segment partially overlaps with the first stent segment in the axial direction, and the first bare segment partially extends beyond the first stent segment in the axial direction.

5. The vascular stent according to claim 1, characterized in that: The included angle between the extension direction of the first bare segment and the axial direction of the vascular stent is 0°-60°.

6. The vascular stent according to any one of claims 1 to 5, characterized in that: The vascular stent also includes a second bare segment, which includes at least one second protrusion formed by weaving metal wires in the circumferential direction, and the proximal end of the second bare segment is connected to the distal end of the second stent segment.

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