Double-layer stent and artificial vein valve

Abstract

The utility model provides a double-layer stent and an artificial vein valve, and relates to the technical field of artificial vein valves. The double-layer stent comprises an outer stent, an inner stent and one or more stent connecting rods, wherein the inner stent is arranged in the outer stent and used for arranging valve leaflets, and the outer stent and the inner stent are connected through the stent connecting rods. Wherein a gap is formed between the outer support and the inner support, and the minimum distance between the outer support and the inner support is larger than zero.

Description

Technical Field

[0001] This specification relates to the field of artificial venous valves, and in particular to a double-layer stent and an artificial venous valve. Background Technology

[0002] Artificial venous valves are used for lower extremity venous diseases and generally consist of a stent and leaflets, with the leaflets fixed to the stent. Because the stent of the artificial venous valve adheres to the inner wall of the vein and exerts a supporting force to fix the valve, it is prone to endothelial hyperplasia. After the endothelium thickens, the proliferating tissue migrates to the leaflets, causing the leaflet edges to thicken and stiffen. Simultaneously, because the proliferating tissue attached to the leaflets is continuous with the venous endothelium, it restricts leaflet movement, affecting leaflet closure and leading to partial or complete failure of the artificial venous valve. Utility Model Content

[0003] This specification provides one or more embodiments of a double-layer stent for use in artificial venous valves. It can be applied to lower limb artificial venous valves, and is suitable for lower limb venous diseases. It is applicable to environments with valve sizes less than 20 mm and environments with valve sizes of 13 mm-15 mm. The double-layer stent includes: an outer stent, an inner stent disposed inside the outer stent for setting valve leaflets, and one or more stent connecting rods connecting the outer stent and the inner stent. A gap exists between the outer stent and the inner stent, and the minimum gap between the outer stent and the inner stent is greater than zero.

[0004] In some embodiments, the inner support includes one or more leaflet fixing assemblies, each leaflet fixing assembly including two curved rods connected by a connection point; a gap exists between the two curved rods and the outer support; the support connecting rod is connected to the connection point of the curved rod, an outer end point on the curved rod away from the connection point, and / or the middle portion of the curved rod.

[0005] In some embodiments, the internal support includes two or more leaflet fixing components; the internal support also includes an auxiliary fixing component, the two ends of which are respectively connected to the curved rods of different leaflet fixing components; the support connecting rod is connected to the auxiliary fixing component.

[0006] In some embodiments, a guiding component is provided between the outer support and the inner support, the guiding component being used to guide the extension direction of the proliferating tissue.

[0007] In some embodiments, the guiding component is provided with an inhibitory coating for inhibiting tissue proliferation and / or inhibiting thrombus formation.

[0008] In some embodiments, the guide component is strip-shaped and includes a first side and a second side. The first side is connected to the inner edge of the outer bracket, and the second side is connected to the outer edge of the inner bracket. The guide component extends along the outer edge of the inner bracket and its shape matches the shape of the outer edge of the inner bracket. The outer bracket is externally circumscribed on a first curved surface, and the first side of the guide component is located on the first curved surface.

[0009] In some embodiments, the external support includes: a proximal support frame, a distal support frame, and a plurality of support rods connecting the proximal support frame and the distal support frame, wherein one or more of the plurality of support rods are pocket-shaped support rods; an accommodating space for accommodating the internal support is formed between the interior of the proximal support frame, the interior of the distal support frame, and / or between the plurality of support rods.

[0010] In some embodiments, the support connecting rod includes: a first support connecting rod connecting one end of the distal end support frame and the curved rod, a second support connecting rod connecting the distal end support frame and the auxiliary fixing assembly, and / or a third support connecting rod connecting the proximal end support frame and the other end of the curved rod.

[0011] In some embodiments, the outer support includes: an arc-shaped support frame and a release mechanism disposed at one end of the arc-shaped support frame; the interior of the arc-shaped support frame forms an accommodating space for accommodating the inner support; the support connecting rod connects one end of the curved rod and the arc-shaped support frame, and / or the support connecting rod connects the middle part of the curved rod and the arc-shaped support frame.

[0012] In some embodiments, the support connecting rod extends from the curved rod toward the distal end and bends to form an arc-shaped foot structure, the arc-shaped foot structure further extends toward the proximal end and connects to the arc-shaped support frame.

[0013] In some embodiments, the bracket connecting rod extends along the radial direction of the outer bracket, or the bracket connecting rod has an angle with the radial direction of the corresponding outer bracket.

[0014] In some embodiments, the outer support is externally connected to a first curved surface, the inner support is internally connected to a second curved surface, and there is a gap between the first curved surface and the second curved surface.

[0015] In some embodiments, the outer support includes a plurality of interconnected outer support members arranged in a grid pattern; the cross-sectional area of ​​the outer support members of the outer support is smaller than the cross-sectional area of ​​the inner support members of the inner support.

[0016] In some embodiments, the inner side of the external stent is provided with a membrane, and the membrane is provided with an inhibitory coating that inhibits tissue proliferation and / or inhibits thrombus formation.

[0017] This specification provides one or more embodiments of an artificial venous valve, which includes a double-layer stent as described in any embodiment of this specification, and further includes leaflets disposed on the inner stent. Attached Figure Description

[0018] This specification will be further described by way of exemplary embodiments, which will be described in detail with reference to the accompanying drawings. The same numbers in the drawings denote the same structures or steps.

[0019] Figure 1 This is a front view schematic diagram of a double-layer bracket according to some embodiments of this specification.

[0020] Figure 2 This is a side view schematic diagram of a double-layer bracket according to some embodiments of this specification.

[0021] Figure 3 This is a top view schematic diagram of a double-layer support according to some embodiments of this specification.

[0022] Figure 4 This is a front view schematic diagram of a double-layer scaffold covered with film according to some embodiments of this specification.

[0023] Figure 5 This is a side view schematic diagram of the coating of a double-layer scaffold according to some embodiments of this specification.

[0024] Figure 6 , Figure 7 This is a schematic diagram of the first support connecting rod, the second support connecting rod, and the third support connecting rod of the double-layer bracket according to some embodiments of this specification.

[0025] Figure 8 This is a schematic diagram of an auxiliary fixing component for a double-layer bracket according to some embodiments of this specification.

[0026] Figure 9 This is a schematic diagram of a guide assembly for a double-layer support according to some embodiments of this specification.

[0027] Figure 10 yes Figure 9 A magnified view of a portion of the image.

[0028] Figure 11 , Figure 12 This is a schematic diagram of the pocket-shaped space of a double-layered support according to some embodiments of this specification.

[0029] Figure 13This is a front view schematic diagram of a single-sided valve embodiment of a double-layer stent shown in some embodiments of this specification.

[0030] Figure 14 This is a top view schematic diagram of a single-sided valve embodiment of a double-layer stent shown in some embodiments of this specification.

[0031] Figure 15 This is a schematic diagram illustrating the usage of a single-sided valve embodiment of a double-layer stent according to some embodiments of this specification.

[0032] Figure 16 This is a schematic diagram of the usage state of a single-sided valve embodiment of a double-layer stent according to another embodiment of this specification.

[0033] Figure 17 This is a front view schematic diagram of an arc-shaped support frame for a double-layer bracket, as shown in some embodiments of this specification.

[0034] Figure 18 This is a side view schematic diagram of the arc-shaped support frame of the double-layer bracket according to some embodiments of this specification.

[0035] Figure 19 This is a top view schematic diagram of the arc-shaped support frame of the double-layer bracket according to some embodiments of this specification.

[0036] Figure 20 This is a three-dimensional schematic diagram of an arc-shaped support frame for a double-layer bracket, as shown in some embodiments of this specification.

[0037] Figure 21 This is a schematic diagram showing the angle between the stent connecting rod of a double-layer stent and the radial direction of a vein, according to some embodiments of this specification.

[0038] Reference numerals: 1 External stent; 11 Proximal support frame; 12 Distal support; 13 Support rod; 131 Pocket-shaped support rod; 14 Arc-shaped support frame; 141 First arc-shaped rod; 142 Second arc-shaped rod; 15 Release structure; 2 Internal stent; 21 Leaflet fixation assembly; 22 Curved rod; 221 Connection point; 222 External connection point; 23 Auxiliary fixation assembly; 231 Auxiliary fixation rod; 3 Stent connecting rod; 31 First stent connecting rod; 32 Second stent connecting rod; 33 Third stent connecting rod; 34 First part; 35 Second part; 4 Guiding assembly; 5 Arc-shaped foot structure; 6 Cover; 7 Leaflet; 8 Pocket-shaped space; 9 Vein. Detailed Implementation

[0039] To more clearly illustrate the technical solutions of the embodiments in this specification, the embodiments will be described in detail below with reference to the accompanying drawings. Obviously, the content described below are some examples or embodiments of this specification. For those skilled in the art, without creative effort, the technical solutions or means disclosed in this specification can be applied to other scenarios based on this technical content.

[0040] It should be understood that the terms "system," "device," "unit," and / or "module" used in this specification are a method of distinguishing different components, elements, parts, sections, or assemblies at different levels. However, if other terms can achieve the same purpose, they may be replaced by other expressions.

[0041] Unless otherwise specified, the technical terms used to describe components, elements, etc. in this specification are not singular but may include plural. Generally speaking, terms such as "comprising" or "including" only indicate that explicitly identified steps, elements, or components are included, and these steps, elements, and components do not constitute an exclusive list, as the described method or apparatus may also include other steps or components.

[0042] Artificial venous valves generally consist of a stent and leaflets, with the leaflets fixed to the stent. The stent needs to provide good support to ensure the leaflets are effectively secured in the blood vessel. Its materials can include metals, polymers, and biomaterials, with metals including tantalum, medical-grade stainless steel, and nickel-titanium alloys. The stent can have a folded and an open state. Generally, before implantation into a vein, the stent is in a folded state to compress into the sheath of the catheter. The artificial venous valve then enters the vein through the catheter. Upon reaching the target implantation location, the stent detaches from the sheath and opens. The artificial venous valve then supports the blood vessel at the target implantation location and functions as a replacement for the native venous valve. In some embodiments, when the stent is open, the proximal end of the leaflet (i.e., the side of the leaflet facing the heart after implantation) can form a pocket-shaped space (or, in other words, the stent bulges radially away from the center of the blood vessel). This allows blood flow to bypass the pocket-shaped space, preventing venous blood from stagnating and forming thrombi in the angled area between the leaflet and the vessel wall.

[0043] In some embodiments, after implantation of a prosthetic venous valve, tissue hyperplasia of the venous wall can occur due to the irritation caused by the stent of the prosthetic valve. This tissue hyperplasia is an unavoidable phenomenon and may occur within one year of implantation. Since the lifespan of a prosthetic venous valve varies from several years to decades, this tissue hyperplasia can have a long-term impact on its function.

[0044] In some related embodiments, the artificial venous valve is designed as a single-layer stent. Because the stent adheres to the inner wall of the vein and exerts a supporting force to fix the valve, endothelial hyperplasia is easily induced. In some embodiments, the leaflets are sutured to the stent. Since the stent is in direct contact with the vascular endothelium, endothelial cells proliferate along the leaflet edge and adhere to the entire leaflet, causing the leaflet edge to thicken and stiffen. Simultaneously, because the proliferating tissue adhering to the leaflet is continuous with the venous endothelium, it restricts leaflet movement, affecting leaflet closure and leading to partial or even complete failure of the artificial venous valve. Therefore, how to avoid the impact of proliferating tissue on the leaflets is a problem worthy of investigation.

[0045] Therefore, some embodiments of this specification propose a double-layer stent, which reserves space for tissue proliferation in the inner wall of the vein through the double-layer stent structure, thereby preventing the proliferating tissue from affecting the valve leaflet function.

[0046] Figures 1 to 3 These are front, side, and top views of a double-layer bracket shown in some embodiments of this specification. See also: Figures 1 to 3 As shown, one or more embodiments of this specification provide a double-layer stent that may include: an outer stent 1, an inner stent 2 disposed inside the outer stent 1 for setting leaflets 7, and one or more stent connecting rods 3 connecting the outer stent 1 and the inner stent 2. A gap exists between the outer stent 1 and the inner stent 2, and the minimum gap between the outer stent 1 and the inner stent 2 is greater than zero. A reserved space is formed between the outer stent 1 and the inner stent 2 to accommodate tissue proliferation of the venous wall and prevent proliferating tissue from adhering to the leaflets on the inner stent 2. The stent connecting rods 3 are used to maintain the inner stent 2 inside the outer stent 1 and to maintain the reserved space.

[0047] In some embodiments, the outer support 1 may be externally connected to a first curved surface (e.g., the inner surface of the outer support 1 is located within the first curved surface), and the inner support 2 may be internally connected to a second curved surface (e.g., the outer surface of the inner support 2 is located within the second curved surface), with a gap between the first and second curved surfaces. The first curved surface can be understood as the internal curved surface of the outer support 1; the second curved surface can be understood as the external curved surface of the inner support 2.

[0048] The aforementioned reserved space design of the double-layer stent can prevent excessive endothelial proliferation onto leaflet 7 after artificial venous valve implantation, which would lead to thickening of leaflet 7, continuity between leaflet 7 and the inner wall of the vein and the proliferating tissue, thereby restricting the opening and closing of leaflet 7 and affecting the long-term opening of the valve.

[0049] In some embodiments, the stent 2 includes one or more leaflet fixation assemblies 21. Exemplarily, in a single-leaflet prosthetic venous valve, the stent 2 includes one leaflet fixation assembly 21. In a bileaflet prosthetic venous valve and a trileaflet prosthetic venous valve, the stent 2 includes two and three leaflet fixation assemblies 21, respectively. The leaflet fixation assemblies 21 are used to fix the leaflets 7. In some embodiments, each leaflet fixation assembly 21 fixes one leaflet 7.

[0050] In some embodiments, see Figure 1 , Figure 2 As shown, the leaflet fixation assembly 21 includes two curved rods 22 connected by a connection point 221. In some embodiments, the distal ends of the two curved rods 22 are connected by the connection point 221, and the proximal ends of the two curved rods 22 are spaced apart, with the leaflet 7 fixed between the two curved rods 22. In some embodiments, the leaflet 7 has a free edge and a fixed edge, wherein the fixed edges on both sides of the leaflet 7 are fixedly connected to the two curved rods 22 by means such as suturing, and the free edge of the leaflet 7 is located at the proximal end and between the spaced proximal ends of the two curved rods 22. In some embodiments, the free edge of one leaflet 7 can cooperate with other leaflets 7 or with the inner wall of a vein, thereby realizing the opening and closing of the valve.

[0051] In some embodiments, a gap exists between the two curved rods 22 and the outer stent 1, providing the aforementioned reserved space. In some embodiments, when viewed from the projection of the outer stent 1 and the inner stent 2 onto the cross-section of the vein, the distance between the innermost point of the outer stent 1 and the outermost point of the curved rod 22 of the inner stent 2 (i.e., the minimum distance between the inner stent 2 and the outer stent 1) can be 0~3mm (excluding 0mm), specifically 1~2mm. For example, this distance can be 0.1mm, 0.5mm, 0.8mm, 1mm, 1.25mm, 2mm, 2.33mm, 2.8mm, or 3mm.

[0052] In some embodiments, the spacing between the outer stent 1 and the inner stent 2 can be equal at all points. In other embodiments, the spacing between the outer stent 1 and the inner stent 2 may not be completely equal. For example, the spacing at the stent connecting rod 3 between the outer stent 1 and the inner stent 2 is greater than the spacing at other parts of the outer stent 1 and the inner stent 2. Since proliferative tissue is more likely to grow along the stent connecting rod 3, by setting the spacing at the stent connecting rod 3 to be larger, it is possible to effectively prevent proliferative tissue that has climbed along the stent connecting rod 3 from affecting the leaflet 7 in some cases.

[0053] In some embodiments, when the artificial venous valve is first implanted, the gap between the curved rod 22 and the external stent 1 may cause paravalvular leakage. However, given the small size of this reserved space, the flow rate of the paravalvular leakage has virtually no impact on the valve's primary functions of opening and closing. Simultaneously, with the inevitable proliferation of venous wall tissue, the venous endothelium gradually thickens and fills the reserved space, further improving the paravalvular leakage until it disappears.

[0054] In some related embodiments, artificial valves (including artificial venous valves and other types of valves) can be used in environments with large inner diameters and high blood flow rates, such as environments with an inner diameter or valve size greater than 20 mm, environments with an inner diameter or valve size of 20 mm-30 mm, and environments with an inner diameter or valve size of 38 mm-57 mm. Due to the characteristics of these environments with large inner diameters and high blood flow rates, the use of double-layer stents can easily lead to severe paravalvular leakage. In this environment, the double-layer stent can employ a skirt structure to completely seal the gap between the outer and inner stents to avoid severe paravalvular leakage. In these related embodiments, due to the high blood flow rate, the environment itself is less prone to tissue hyperplasia, and because of the large inner diameter, the distance between the outer and inner stents in the double-layer stent is large, thus allowing for a larger skirt structure, making it difficult for proliferating tissue to adhere to the valve leaflets.

[0055] The double-layered stents of one or more embodiments of this specification can be deployed in environments with small inner diameters and slow blood flow rates, such as veins with an inner diameter or valve size of 20 mm or less (e.g., lower extremity veins), or vessels with an inner diameter or valve size of 7 mm, 9 mm, 11 mm, 13 mm, or 15 mm. In such environments, tissue hyperplasia is more likely to occur and adhere to the valve leaflets, making skirting or closure of the gap between the outer and inner stents unsuitable and without technical inspiration. In one or more embodiments of this specification, the reserved space formed between the outer stent 1 and the inner stent 2 addresses tissue hyperplasia, and the tissue hyperplasia filling the reserved space addresses smaller paravalvular leaks in such environments.

[0056] In some embodiments, the support connecting rod 3 is connected to the connection point 221 of the curved rod 22, the outer end point 222 of the curved rod 22 away from the connection point 221, and / or the middle portion of the curved rod 22. Exemplarily, there may be one support connecting rod 3, which can be connected to any one of the connection point 211, the outer end point 222, or the middle portion of the curved rod 22. Exemplarily, there may be two support connecting rods 3, which can be connected to the connection point 221 of the curved rod 22 in each of the two leaflet fixing assemblies 21, or to the outer end points 222 of each of the two curved rods 22, or to the middle portions of each of the two curved rods 22. Exemplarily, there may be two support connecting rods 3, which can be connected to any two of the connection point 211, the outer end point 222, or the middle portion of the curved rod 22. For example, the double-layer stent may further include more stent connecting rods 3, which are respectively connected to the connection point 211, the external end point 222, and the middle of the curved rod 22. In some embodiments, fewer stent connecting rods 3 can reduce the supporting force on the external stent 1 while maintaining a certain stability of the inner stent 2, thereby reducing the stimulation of the vein wall by the external stent 1. In some embodiments, arranging more stent connecting rods 3 can better maintain the stability of the inner stent 2. In some embodiments, when arranging multiple or multiple sets of stent connecting rods 3, the straight line where the two connection points 211 in the two leaflet fixation components 21 are located intersects or is further perpendicular to the straight line where the two external end points 222 are located, so the stent connecting rods 3 arranged accordingly also face different directions, thereby obtaining the anisotropic stability of the inner stent 2. In some embodiments, the stent connecting rods 3 near the proximal end or near the distal end can be arranged according to the venous environment. The connection point positions of the multiple stent connecting rods 3 provided in this application allow users to select double-layer stents with different stability, different irritation, and adaptability to various environments based on the environment.

[0057] In some embodiments, the curved rod 22 of the leaflet fixation assembly 21 can form a V-shaped structure or a U-shaped structure. In some embodiments, taking a bileaflet artificial venous stent valve as an example, the two leaflet fixation assemblies 21 have the same shape; for example, the two leaflet fixation assemblies 21 can form a double V-shaped structure or a double U-shaped structure. In other possible applications, the V-shaped structure or U-shaped structure can also be applied to other possible forms of valves besides bileaflet valves, such as single-leaflet valves or trileaflet valves.

[0058] In some embodiments, taking a bileaflet artificial venous stent valve as an example, see [link to relevant documentation]. Figure 1 , Figure 2 As shown, the cranks 22 in the two leaflet fixing assemblies 21 can share the same external terminal 222.

[0059] In some embodiments, the internal support 2 includes two or more leaflet fixation assemblies 21. See also Figures 6 to 8 As shown, the stent includes two leaflet fixation assemblies 21, which can be arranged facing each other to form the aforementioned bileaflet artificial venous stent valve. Exemplarily, the proximal ends of the two leaflet fixation assemblies 21 are connected to each other so that the free ends of the two leaflets 7 of the two leaflet fixation assemblies 21 are brought close together. The valve opens or closes by the separation or closure of the free ends of the two leaflets 7 based on the impact of fluid, such as blood, on the leaflets 7. Exemplarily, the distal ends of the two leaflet fixation assemblies 21 are spaced apart so that the leaflets 7 can cover the portion of the vein's cross-section other than the aforementioned reserved space.

[0060] In some embodiments, because the external stent 1 is subjected to inward pressure from the inner wall of the vein, this inward pressure may be transmitted to the inner stent 2 through the stent connecting rod 3. Therefore, the distal ends of the two leaflet fixation assemblies 21 of the inner stent 2 (i.e., Figures 6 to 8 The lower ends of the two leaflet fixation assemblies 21 tend to move closer together, which may lead to the problem of increased perivalvular leakage in some related embodiments. In some embodiments, the stent 2 may further include an auxiliary fixation component 23, the two ends of which are respectively connected to the curved rods 22 of different leaflet fixation assemblies 21. The auxiliary fixation component 23 can be used to support the distal ends of the two leaflet fixation assemblies 21 to counteract their tendency to move closer together; at the same time, it can maintain the stability of the stent 2.

[0061] In some embodiments, the number of auxiliary fixing components 23 may be two. One auxiliary fixing component 23 is connected to two cranks 22 on one side of the two leaflet fixing components 21, and the other auxiliary fixing component 23 is connected to two cranks 22 on the other side of the two leaflet fixing components 21.

[0062] In some embodiments, the auxiliary fixation component 23 may include two auxiliary fixation rods 231, one end (e.g., distal end) of which is connected to each other, and the other end (e.g., proximal end) of which is connected to the curved rod 22 (e.g., the middle part of the curved rod 22) of different leaflet fixation components 21. In some embodiments, the two auxiliary fixation rods 231 may have an included angle. In some embodiments, the two auxiliary fixation rods 231 may be V-shaped or U-shaped to form a certain structural elasticity, suitable for the overall folding or unfolding of the stent.

[0063] In some embodiments, see Figures 8 to 10As shown, a guiding component 4 is provided between the outer stent 1 and the inner stent 2. The guiding component 4 is used to guide the extension direction of the proliferating tissue. To a certain extent, the guiding component 4 guides the proliferating tissue to extend from the outer stent 1 to the inner stent 2, thereby filling the aforementioned reserved space and reducing or even eliminating paravalvular leakage.

[0064] In some embodiments, the guide component 4 may be provided with an inhibitory coating for inhibiting tissue proliferation and / or thrombus formation. In some embodiments, the inhibitory coating may be a coating of heparin and / or paclitaxel, etc. In some embodiments, the coating on the guide component 4 may be used to reduce or inhibit tissue proliferation, preventing the proliferating tissue on the guide component 4 from further adhering to the leaflet 7. In some embodiments, the guide component 4 may be made of the same material as the outer stent 1 and the inner stent 2. In some embodiments, the guide component 4 may be made of nickel-titanium alloy. By using the same material as the outer stent 1 and the inner stent 2 for the guide component 4, it is possible to integrally mold the guide component 4 with the outer stent 1 and / or the inner stent 2, which facilitates processing. In some embodiments, the guide component 4 may be the same as the covering material; for example, the material of the guide component 4 may be bovine pericardium, porcine pericardium, etc.

[0065] It should be noted that in some relevant cases, tissue hyperplasia or thickening of the venous endothelium due to mechanical pressure is difficult to avoid by adjusting factors such as the structure and material of the external stent 1. Based on this, designers or users expect to guide this immutable hyperplastic tissue so that it attaches to the guide component 4 rather than the leaflet 7.

[0066] It should be further clarified that the proliferation of venous endothelial tissue does not actually grow and extend indefinitely. Based on practical experience, the thickness of the tissue proliferation (the thickness extending from the inner wall of the vein towards the center of the vein) may be 0-3 mm. Therefore, the guiding component 4 is arranged within this range to guide the proliferating tissue to adhere to the guiding component 4, thus avoiding impact on the valve leaflet 7 and filling the aforementioned reserved gap. In some embodiments, the guiding component 4 is configured with sufficient width, for example, its width may be greater than the maximum proliferating thickness of the venous endothelium in practical experience, thereby preventing tissue proliferation onto the valve leaflet 7.

[0067] In some embodiments, the guiding component 4 may be strip-shaped. Exemplarily, the guiding component 4 includes a first side and a second side, the first side being connected to the inner edge of the outer stent 1, and the second side being connected to the outer edge of the inner stent 1. In some embodiments, the guiding component 4 extends along the outer edge of the inner stent 2 and its shape matches the shape of the outer edge of the inner stent 2, thereby guiding the proliferating tissue to fill the gap between the outer stent 1 and the inner stent 2, while simultaneously matching the filling direction with the outer edge of the inner stent 2 as much as possible. In some embodiments, the outer stent 1 is circumscribed on a first curved surface (e.g., a first curved surface parallel to the inner wall of the vein and located inside the outer stent 1), and the first side of the guiding component 4 is located on the first curved surface. In some embodiments, from a perspective in the axial direction of the vein, the guiding component may be annular.

[0068] In some embodiments, see Figures 1 to 3 , Figures 4 to 5 as well as Figures 6 to 10 In the various embodiments shown, the outer support 1 may include: a proximal support frame 11, a distal support frame 12, and a plurality of support rods 13 connecting the proximal support frame 11 and the distal support frame 12, wherein one or more of the support rods 13 include pocket-shaped support rods 131. In some embodiments, an accommodating space for accommodating the inner support 2 is formed between the interior of the proximal support frame 11, the interior of the distal support frame 12, and / or between the plurality of support rods 13.

[0069] In some embodiments, the proximal support frame 11, the distal support frame 12, and the support rod 13 may form a cylindrical or substantially cylindrical structure.

[0070] In some embodiments, the proximal support frame 11 and the distal support frame 12 can be in a mesh shape, for example... Figure 1 and Figure 2 The grid shown is generally diamond-shaped. In some embodiments, the proximal support frame 11 and the distal support frame 12 may include a plurality of external support members arranged intersectingly to form a grid, which, for example, may be generally diamond-shaped.

[0071] See Figure 11 , Figure 12 As shown, in some embodiments, when the double-layer stent is deployed, the pocket-shaped support rod 131 protrudes radially away from the central axis of the outer stent 1 to form a pocket-shaped space 8 on the proximal side of the leaflet fixation assembly 21 (or leaflet 7). After the artificial venous valve is implanted into the blood vessel, blood flow can form a bypass flow in the pocket-shaped space 8, preventing venous blood from stagnating in the angled area between the leaflet 7 and the inner wall of the vein, thus preventing thrombosis. Figure 11 The diagram shows the state where the free edges of the two leaflets 7 are far apart and the artificial venous valve is open, with arrows indicating the direction of blood flow and the flow around the pocket-shaped space 8. Figure 12 The diagram shows the state where the free edges of the two leaflets 7 are close to each other and the artificial venous valve is closed, with arrows indicating the flow around the pocket-shaped space 8.

[0072] In some embodiments, see Figure 6 , Figure 7 As shown, the support connecting rod 3 includes: a first support connecting rod 31 connecting one end of the distal end support frame 12 and the curved rod 22; a second support connecting rod 32 connecting the distal end support frame 12 and the auxiliary fixing assembly 23; and / or a third support connecting rod 33 connecting the other end of the proximal end support frame 11 and the curved rod 22. In some embodiments, there may be one or more of the first support connecting rod 31, the second support connecting rod 32, and the third support connecting rod 33. In some embodiments, the double-layer support may include one or more of the first support connecting rod 31, the second support connecting rod 32, and the third support connecting rod 33.

[0073] For example, Figure 1 , Figure 2 An embodiment of a bileaflet artificial venous valve is shown, wherein an outer stent 1 and an inner stent 2 are connected by a first stent connecting rod 31. In some embodiments, each of the two leaflet fixation assemblies 21 of the inner stent 2 of the bileaflet artificial venous valve is connected to the outer stent 1 via a first stent connecting rod 31. In some embodiments, the two first stent connecting rods 31 are arranged mirror-symmetrically with respect to the axis of the outer stent 1.

[0074] For example, Figure 6 , Figure 7 Another embodiment of a bileaflet artificial venous valve is shown, wherein the outer stent 1 and the inner stent 2 are connected by a first stent connecting rod 31, a second stent connecting rod 32, and a third stent connecting rod 33. In some embodiments, each of the two leaflet fixation assemblies 21 of the inner stent 2 of the bileaflet artificial venous valve is connected to the outer stent 1 via the first stent connecting rod 31 and the third stent connecting rod 33. Further, two auxiliary fixation assemblies 23 are provided between the two leaflet fixation assemblies 21 of the inner stent 2 of the bileaflet artificial venous valve, each of the two auxiliary fixation assemblies 23 being connected to the outer stent 1 via the second stent connecting rod 32. In some embodiments, the two first stent connecting rods 31 are arranged mirror-symmetrically with respect to the axis of the outer stent 1, the two second stent connecting rods 32 are arranged mirror-symmetrically with respect to the axis of the outer stent 1, and the two third stent connecting rods 33 are arranged mirror-symmetrically with respect to the axis of the outer stent 1.

[0075] For example, Figure 13 , Figure 14 , Figure 15An embodiment of a single-leaflet artificial venous valve is shown, wherein an outer stent 1 and an inner stent 2 are connected by a first stent connecting rod 31 and a third stent connecting rod 33. In some embodiments, the inner stent 2 of the single-leaflet artificial venous valve has a leaflet fixation assembly 21, which is connected to the outer stent 1 via a first stent connecting rod 31. In some embodiments, the leaflet fixation assembly 21 is connected to the outer stent 1 via two third stent connecting rods 33, which are arranged mirror-symmetrically with respect to the axis of the outer stent 1.

[0076] For example, Figure 16 Another embodiment of a single-leaf artificial venous valve is shown, wherein the outer stent 1 and the inner stent 2 are connected by a first stent connecting rod 31.

[0077] In some embodiments, in the proximal support frame 11 and the distal support frame 12, the cross-arranged outer support rods can form a grid intersection point, and the first support connecting rod 31, the second support connecting rod 32, and the third support connecting rod 33 can be connected to the grid intersection point of the proximal support frame 11 or the grid intersection point of the distal support frame 12.

[0078] In some embodiments, the support connecting rod 3 (e.g., the first support connecting rod 31 or the third support connecting rod 33) may include an arcuate first portion 34 connected to the outer support 1 and extending in the direction from the outer support 1 to the inner support 2, and an arcuate second portion 35 connected to the inner support 2 and extending in the axial direction of the outer support 1.

[0079] In one or more embodiments of this specification, see Figures 17 to 20 As shown, an outer support 1 with an overall arcuate profile is provided. In some embodiments, the outer support 1 may be spherical or ellipsoidal. In some embodiments, the outer support 1 may include: an arcuate support frame 14 and a release mechanism 15 disposed at one end of the arcuate support frame 14. The interior of the arcuate support frame 14 forms an accommodating space for receiving an inner support 2. The release mechanism 15 can be connected to or disconnected from a conveying mechanism for conveying the double-layer support to a target location.

[0080] See Figure 20As shown, in some embodiments, the arc-shaped support frame 14 includes multiple sets of first arc-shaped rods 141 arranged in a cross configuration, and second arc-shaped rods 142 connected to the proximal ends of the first arc-shaped rods 141. One end of the second arc-shaped rod 142 is connected to the first arc-shaped rod 141, and the other end is connected to a release mechanism 15. In some embodiments, the release mechanism 15 has a slot for receiving the second arc-shaped rod 142 to provide space for the retraction of the second arc-shaped rod 142 in the retracted state. In some further embodiments, the arc-shaped support frame 14 includes four sets of first arc-shaped rods 141 arranged in a cross configuration, with a generally rhomboid or rectangular grid formed between two adjacent sets of cross-arranged first arc-shaped rods 141, and the second arc-shaped rods 141 can be connected to the ends of the grid (e.g., the proximal ends).

[0081] In some embodiments, the arc-shaped support frame 14 is provided with an inner support 2. The inner support 2 may include a single leaflet fixing assembly 21 similar to that described above, or two leaflet fixing assemblies 21 that are mirror-symmetrical with respect to the axis of the arc-shaped support frame 14, or three or more leaflet fixing assemblies 21 arranged in a circular array around the axis of the arc-shaped support frame 14. The leaflet fixing assembly 21 has a curved rod 22 similar to that described above, which will not be repeated here.

[0082] In some embodiments, the support connecting rod 3 connects one end of the curved rod 22 to the arcuate support frame 14, and / or the support connecting rod 3 connects the middle part of the curved rod 22 to the arcuate support frame 14. In some embodiments, the support connecting rod may be connected to the end of the aforementioned grid (e.g., the distal end).

[0083] In some embodiments, the stent connecting rod 3 extends from the curved rod 22 towards the distal end and bends to form an arc-shaped foot structure 5. The arc-shaped foot structure 5 further extends towards the proximal end and connects to the arc-shaped support frame 14. In some embodiments, the arc-shaped foot structure 5 is U-shaped. In some embodiments, the arc-shaped foot structure 5 tends to extend inward from the outer stent 1 to avoid forming sharp portions at the ends of the double-layer stent, thereby stimulating hyperplasia of the venous wall. On the other hand, the U-shaped structure of the arc-shaped group structure 5 creates structural elasticity between the outer stent 1 and the inner stent 2, allowing for adaptive contraction of the outer stent 1 while maintaining the gap between the outer stent 1 and the inner stent 2.

[0084] In some embodiments, the support connecting rod 3 (e.g., the arc-shaped foot structure 5) may include an arc-shaped first portion 34 connected to the outer support 1 and extending in the direction from the outer support 1 to the inner support 2, and an arc-shaped second portion 35 connected to the inner support 2 and extending in the axial direction of the outer support 1.

[0085] In some embodiments, the bracket connecting rod 3 extends radially along the outer bracket 1. In some other embodiments, see [link to other embodiments]. Figure 21 As shown, the stent connecting rod 3 has an angle θ between its radial direction and that of the corresponding outer stent. This angle θ allows rotation between the outer stent 1 and the inner stent 2, facilitating the inward retraction of the outer stent 1 to adapt to a folded state or the working environment. Furthermore, since the outer stent 1 is easier to retract inward compared to embodiments without an angle, it further reduces irritation to the venous wall. In some embodiments, the outer stent 1 may twist relative to the inner stent 2 after implantation into the vein. This angle θ also allows compensation for the relative twisting of the outer stent 1, enabling the stent connecting rod 3 to adaptively adjust the angle according to the relative twisting of the outer stent 1, preventing bending, twisting, and / or folding damage to the middle portion of the stent connecting rod 3. In some embodiments, the double-layer stent requires loading before implantation into the vein, for example, by compressing the entire double-layer stent into a sheath. This angle θ provides a guiding direction for the compression and folding of the double-layer stent during installation, guiding the direction of twisting of the outer stent 1 relative to the inner stent 2, and preventing bending, twisting, and / or folding damage to the middle portion of the stent connecting rod 3. In some embodiments, the included angle θ can be 0~90°, for example 30~60°, or even 40~50°. For example, the included angle θ can be 28°, 30°, 40°, 45°, 55°, 68°, or 75°.

[0086] In some embodiments, the cross-sectional area of ​​the outer stent member of the outer stent 1 is equal to the cross-sectional area of ​​the inner stent member of the inner stent 2, thereby facilitating stent manufacturing. In some embodiments, the cross-sectional area of ​​the outer stent member of the outer stent 1 is smaller than the cross-sectional area of ​​the inner stent member of the inner stent 2, so that the outer stent 1 has a relatively small supporting force, reducing the mechanical stimulation of the inner wall of the vein by the outer stent 1, while giving the inner stent 2 relatively high stability and ensuring the hydrodynamic performance of the valve. In some embodiments, the cross-sectional area of ​​the outer stent member can be 1 / 3 to 2 / 3 of the cross-sectional area of ​​the inner stent member. In some embodiments, when the cross-sectional area of ​​the outer stent member is different from that of the inner stent member, the cross-sectional area of ​​the stent connecting rod 3 can be gradually set. For example, the cross-sectional area of ​​the end of the stent connecting rod 3 connected to the outer stent is the same as the cross-sectional area of ​​the outer stent member, the cross-sectional area of ​​the end of the stent connecting rod 3 connected to the inner stent is the same as the cross-sectional area of ​​the inner stent member, and the cross-sectional area of ​​the middle part of the stent connecting rod 3 is gradually set.

[0087] In some embodiments, see Figure 4 , Figure 5As shown, a membrane 6 is provided on the inner side of the external stent 1. In some embodiments, the membrane 6 is made of a dense material, and the pore size of the membrane 6 is smaller than the size of vascular endothelial cells to prevent vascular endothelial cells from migrating into the interior of the external stent 1. In some embodiments, the membrane 6 is smoothly disposed to avoid thrombosis. In some embodiments, the membrane material can be a bio-derived material; for example, the membrane material can be bovine pericardium, porcine pericardium, etc. In some embodiments, the membrane 6 can be connected to the external stent 1 by sutures. In some embodiments, the membrane material can also be a polymer material. In some embodiments, the polymer material can be connected to the external stent 1 by processes such as suturing and / or adhesive coating.

[0088] In some embodiments, the coating 6 (e.g., a polymer coating) is provided with an inhibitory coating that inhibits tissue proliferation and / or thrombus formation. In some embodiments, the polymer coating may be provided with a coating such as heparin and paclitaxel to inhibit tissue proliferation and thrombus formation.

[0089] In some embodiments, the thickness of the coating material is less than the gap between the outer support 1 and the inner support 2. In some embodiments, the thickness of the coating material can be 0.15 to 3 mm. In some embodiments, the thickness of the coating material can be 1 / 3 to 2 / 3 of the minimum distance between the outer support 1 and the inner support 2, for example, 1 / 2.

[0090] One or more embodiments of this specification also provide an artificial venous valve stent, including the aforementioned double-layer stent, and further including a leaflet 7 disposed on the inner stent 2.

[0091] One or more embodiments of this specification provide a method for manufacturing a double-layer support, comprising: providing a tube, cutting (e.g., laser cutting) the surface of the tube to obtain an integral outer support portion, an inner support portion, and a support connecting rod portion, and bending the inner support portion and the support connecting rod portion inward to form an outer support 1, an inner support 2 located inside the outer support 1, and a support connecting rod 3 connecting the outer support 1 and the inner support 2. The manufacturing method may further include heat-treating the bent outer support 1, inner support 2, and support connecting rod 3 for shaping.

[0092] One or more embodiments of this specification also provide another method for preparing a double-layer support, which includes: providing a first tube, cutting the surface of the first tube to obtain an outer support 1, providing a second tube, cutting the surface of the second tube to obtain an inner support 2, providing a support connecting rod 3, and welding or riveting the outer support 1 and the support connecting rod 3, and the inner support 2 and the support connecting rod 3.

[0093] The beneficial effects that the embodiments of this specification may bring include, but are not limited to: (1) reserving space for tissue proliferation in the inner wall of the vein through the double-layer stent structure, avoiding the proliferation of tissue from affecting the normal function of the leaflets; (2) the proliferation of tissue gradually fills the reserved space after the double-layer stent is implanted to improve or even eliminate the problem of paravalvular leakage in the early stage of implantation; (3) connecting the inner stent and the outer stent through a variety of selectable connection forms such as the first stent connecting rod, the second stent connecting rod, and the third stent connecting rod to meet different usage needs; (4) the auxiliary fixation component 23 can be used to support and maintain the distance between the distal ends of the two leaflet fixation components and provide a certain structural elasticity so that it is suitable for closing or opening; (5) guiding The component guides the growth direction of the proliferating tissue, enabling it to fill the reserved space; (6) an inhibitory coating is provided on the guiding component to reduce the possibility of tissue proliferation; (7) a membrane is provided on the inner side of the outer stent to reduce the possibility of tissue proliferation; (8) an inhibitory coating is provided on the membrane to reduce the possibility of tissue proliferation; (9) a pocket-shaped space is provided by a pocket-shaped support rod, allowing blood flow to form a bypass in the pocket-shaped space, preventing venous blood from stagnating in the angle area between the valve leaflet and the inner wall of the vein and forming a thrombus; (10) it can be widely applied to single-leaf, double-leaf, triple-leaf and other artificial venous valve stents; (11) it can be widely applied to various cylindrical or spherical artificial venous valve stents. It should be noted that different embodiments may produce different beneficial effects. In different embodiments, the beneficial effects that may be produced can be any one or a combination of the above, or any other possible beneficial effects.

[0094] The basic concepts have been described above. It is obvious that the detailed disclosure above is merely illustrative and does not constitute a limitation of this specification. Although not explicitly stated herein, various modifications, improvements, and corrections may be made to this specification by those skilled in the art. Such modifications, improvements, and corrections are taught in this specification and therefore remain within the spirit and scope of the exemplary embodiments described herein.

Claims

1. A double-layer stent, used in artificial venous valves, characterized in that, include: An outer support, an inner support disposed inside the outer support for setting the leaflets, and one or more support connecting rods connecting the outer support and the inner support; There is a gap between the outer support and the inner support, and the minimum distance between the outer support and the inner support is greater than zero.

2. The double-layer support according to claim 1, characterized in that, The internal support includes one or more leaflet fixing assemblies, each leaflet fixing assembly including two curved rods connected by a connection point; There is a gap between the two cranks and the outer support; The bracket connecting rod is connected to the connection point of the curved rod, the outer end point of the curved rod away from the connection point, and / or the middle part of the curved rod.

3. The double-layer support according to claim 2, characterized in that, The internal support includes two or more of the leaflet fixation components; The internal support also includes: an auxiliary fixing component, the two ends of which are respectively connected to the curved rods of different leaflet fixing components; The bracket connecting rod is connected to the auxiliary fixing component.

4. The double-layer support according to claim 1, characterized in that, A guiding component is provided between the outer support and the inner support, the guiding component being used to guide the extension direction of the proliferating tissue.

5. The double-layer support according to claim 4, characterized in that, The guiding component is provided with an inhibitory coating for inhibiting tissue proliferation and / or inhibiting thrombus formation.

6. The double-layer support according to claim 4, characterized in that, The guide component is strip-shaped and includes a first side and a second side. The first side is connected to the inner edge of the outer bracket, and the second side is connected to the outer edge of the inner bracket. The guide component extends along the outer edge of the inner support and its shape matches the shape of the outer edge of the inner support. The outer support is externally connected to the first curved surface, and the first side of the guide component is located on the first curved surface.

7. The double-layer support according to claim 1, characterized in that, The external support includes: a proximal support frame, a distal support frame, and a plurality of support rods connecting the proximal support frame and the distal support frame, wherein one or more of the plurality of support rods are pocket-shaped support rods; An accommodating space for accommodating the inner support is formed between the interior of the proximal support frame, the interior of the distal support frame, and / or between the plurality of support rods.

8. The double-layer support according to claim 3, characterized in that, The external support includes: a proximal support frame, a distal support frame, and a plurality of support rods connecting the proximal support frame and the distal support frame, wherein one or more of the plurality of support rods are pocket-shaped support rods; An accommodating space for accommodating the inner support is formed between the interior of the proximal end support frame, the interior of the distal end support frame, and / or between the plurality of support rods; The bracket connecting rod includes: a first bracket connecting rod connecting one end of the distal end support frame and the curved rod, a second bracket connecting rod connecting the distal end support frame and the auxiliary fixing assembly, and / or a third bracket connecting rod connecting the proximal end support frame and the other end of the curved rod.

9. The double-layer support according to claim 3, characterized in that, The external support includes: an arc-shaped support frame and a release mechanism located at one end of the arc-shaped support frame; The interior of the arc-shaped support frame forms an accommodating space for accommodating the inner support; The bracket connecting rod connects one end of the curved rod to the arc-shaped support frame, and / or the bracket connecting rod connects the middle part of the curved rod to the arc-shaped support frame.

10. The double-layer support according to claim 9, characterized in that, The support connecting rod extends from the curved rod toward the distal end and bends to form an arc-shaped foot structure. The arc-shaped foot structure extends further toward the proximal end and connects with the arc-shaped support frame.

11. The double-layer support according to claim 1, characterized in that, The bracket connecting rod extends along the radial direction of the outer bracket, or there is an angle between the bracket connecting rod and the corresponding radial direction of the outer bracket.

12. The double-layer support according to claim 1, characterized in that, The outer support is externally connected to the first curved surface, and the inner support is internally connected to the second curved surface, with a gap between the first curved surface and the second curved surface.

13. The double-layer support according to claim 1, characterized in that, The external support includes multiple interconnected external support rods arranged in a grid pattern; The cross-sectional area of ​​the outer support member of the outer support is smaller than the cross-sectional area of ​​the inner support member of the inner support.

14. The double-layer support according to claim 1, characterized in that, The inner side of the external stent is covered with a membrane, and the membrane is provided with an inhibitory coating that inhibits tissue proliferation and / or thrombus formation.

15. An artificial venous valve, characterized in that, The double-layer stent, as described in any one of claims 1 to 14, further includes leaflets disposed on the inner stent.

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