Artificial vein valve and stent thereof

Abstract

The utility model provides an artificial vein valve and a support thereof, and relates to the technical field of medical instruments. The stent comprises a proximal section supporting frame, a valve leaflet fixing assembly, a pocket-shaped supporting rod and a telecentric section supporting frame. The valve leaflet fixing assembly is connected between the proximal section support frame and the telecentric section support frame and is used for fixing a valve leaflet; the first end of the pocket-shaped supporting rod is connected with the proximal section supporting frame, and the second end of the pocket-shaped supporting rod is connected with the telecentric section supporting frame; the pocket-shaped supporting rod can protrude in the direction away from the central axis of the support in the radial direction of the support when the support is unfolded, so that a pocket-shaped space is formed on the proximal side of the valve leaflet fixing assembly.

Description

Technical Field

[0001] The present specification relates to the technical field of medical devices, and in particular to an artificial venous valve and a stent thereof. Background Art

[0002] The veins are responsible for bringing blood from all parts of the body back to the heart. To prevent blood from flowing back, there are valves in the veins. When blood flows to the heart, the valves open to allow blood to flow to the heart. After the blood flows away, the valves close. The venous valve is a "one-way valve" that ensures that the veins transport blood back to the heart. If the venous valve is damaged or diseased, the venous blood will flow back, causing venous hypertension and chronic venous disease (CVD).

[0003] Some scientists have proposed to manufacture artificial venous valves to replace diseased venous valves. Artificial venous valves can be implanted into the target location of the venous blood vessels (such as damaged or diseased native venous valves), thereby replacing the native venous valves to prevent blood reflux.

[0004] Some embodiments of the present specification aim to provide an artificial venous valve and a stent thereof that has a more stable structure and can better adapt to the intravenous environment of the venous vessel. Utility Model Content

[0005] One or more embodiments of the present specification provide a stent for use in an artificial venous valve, comprising a proximal segment support frame, a leaflet fixing assembly, a pocket-shaped support rod and a distal segment support frame; the leaflet fixing assembly is connected between the proximal segment support frame and the distal segment support frame for fixing the leaflets; the first end of the pocket-shaped support rod is connected to the proximal segment support frame, and the second end thereof is connected to the distal segment support frame; the pocket-shaped support rod can protrude along the radial direction of the stent away from the central axis of the stent when the stent is expanded, so as to form a pocket-shaped space on the proximal side of the leaflet fixing assembly.

[0006] According to the bracket described in some embodiments of the present specification, the pocket-shaped support rod includes more than one S-shaped parts connected in sequence, wherein the opening of at least one semi-arc of at least one S-shaped part is greater than 0, and the opening of the semi-arc is positively correlated with the angle between the tangents of the two endpoints of the semi-arc.

[0007] According to the bracket described in some embodiments of the present specification, the number of the pocket-shaped support rods is more than two; the proximal section support frame includes more than two V-shaped support feet respectively connected to the more than two pocket-shaped support rods; when the bracket is expanded, the V-shaped opening of the V-shaped support feet is greater than a set threshold, and the V-shaped opening is positively correlated with the angle between the two sides forming the V-shaped structure; the first end of the pocket-shaped support rod is connected to the corresponding V-shaped support foot.

[0008] According to the stent described in some embodiments of the present specification, when the stent is expanded, the point on the pocket-shaped support rod that is farthest from the central axis of the stent along the radial direction of the stent has an axial height that is related to the V-shaped opening and / or length of the V-shaped support foot.

[0009] According to the bracket described in some embodiments of the present specification, when the bracket is expanded, the length of the V-shaped supporting leg is smaller than the total length of the more than one S-shaped portions connected in sequence in the pocket-shaped supporting rod.

[0010] According to the bracket described in some embodiments of the present specification, a straight rod is provided between the S-shaped portion of the pocket-shaped support rod close to the distal segment support frame and the second end of the pocket-shaped support rod; and the total length of more than one S-shaped portions connected in sequence in the pocket-shaped support rod is greater than the length of the straight rod.

[0011] According to the stent described in some embodiments of the present specification, in the one or more S-shaped portions connected in sequence in the pocket-shaped support rod, the opening of the semi-arc close to the distal segment support frame is greater than the opening of the semi-arc close to the proximal segment support frame.

[0012] According to the stent described in some embodiments of the present specification, the leaflet fixing assembly includes two curved rods connected in a V-shaped structure; the connection point of the two curved rods is connected to the distal segment support frame, and the external end points of the two curved rods, each away from the connection point, are respectively connected to the proximal segment support frame.

[0013] According to the stent described in some embodiments of the present specification, the orthographic projections of one or more of the pocket-shaped support rods on the axial cross-section of the stent are located between the orthographic projections of the two curved rods in the leaflet fixing assembly on the axial cross-section of the stent.

[0014] According to the stent described in some embodiments of the present specification, the number of the pocket-shaped support rods and the leaflet fixing components are 2 respectively; the two leaflet fixing components are arranged opposite to each other in the circumferential direction of the stent; the orthographic projection of the first pocket-shaped support rod on the axial section of the stent is located in the middle of the orthographic projections of the two curved rods in the first leaflet fixing component on the axial section of the stent, and the orthographic projection of the second pocket-shaped support rod on the axial section of the stent is located in the middle of the orthographic projections of the two curved rods in the second leaflet fixing component on the axial section of the stent.

[0015] According to the stent described in some embodiments of the present specification, the curved rod has more than two arc-shaped portions; a reference plane is determined based on the connection points of the two curved rods in the leaflet fixing assembly and the external end points of the two curved rods, and the more than two arc-shaped portions of the curved rod of the leaflet fixing assembly are distributed on different sides of the reference plane.

[0016] According to the stent described in some embodiments of the present specification, among the two or more arc-shaped portions of the curved rod, the arc-shaped portion close to the distal segment support frame is located on the proximal side of the corresponding reference plane.

[0017] According to the bracket described in some embodiments of the present specification, the curved rod has two arc-shaped portions, the arc-shaped portion close to the distal segment support frame is located on the proximal side of the corresponding reference plane, and the arc-shaped portion away from the distal segment support frame is located on the distal side of the reference plane.

[0018] According to the stent described in some embodiments of the present specification, the proximal segment support frame includes more than two proximal segment support grids; the external end points of the two curved rods in the leaflet fixing assembly are respectively connected to different proximal segment support grids.

[0019] According to the stent described in some embodiments of the present specification, the number of the proximal segment support grid and the leaflet fixing assembly is 2 respectively; the two leaflet fixing assemblies are arranged opposite to each other in the circumferential direction of the stent; the external end point of a curved rod in the first leaflet fixing assembly and the external end point of a curved rod in the second leaflet fixing assembly are both connected to the first positioning ear, and the first positioning ear is connected to the first proximal segment support grid; the external end point of another curved rod in the first leaflet fixing assembly and the external end point of another curved rod in the second leaflet fixing assembly are both connected to the second positioning ear, and the second positioning ear is connected to the second proximal segment support grid.

[0020] According to the stent described in some embodiments of this specification, the first positioning ear and the second positioning ear are respectively provided with two positioning holes distributed along the axial direction of the stent, and the positioning holes are used to fix the leaflets.

[0021] According to the stent described in some embodiments of the present specification, the proximal segment support grid has a V-shaped frame, and the V-shaped frame includes more than one triangular sub-grid and / or more than one quadrilateral sub-grid.

[0022] According to the bracket described in some embodiments of the present specification, it is characterized in that the V-shaped opening of the V-shaped frame is less than or equal to a set threshold, and the V-shaped opening is positively correlated with the angle between two sides forming the V-shaped structure.

[0023] According to the stent described in some embodiments of the present specification, when the stent is expanded, the point on the pocket-shaped support rod that is farthest from the central axis of the stent along the radial direction of the stent is at the same height as the connection point between the external end point of the curved rod in the leaflet fixing assembly and the proximal segment support grid in the axial direction of the stent; or, when the stent is expanded, the point on the pocket-shaped support rod that is farthest from the central axis of the stent along the radial direction of the stent is closer to the distal segment support frame in the axial direction of the stent than the connection point between the external end point of the curved rod in the leaflet fixing assembly and the proximal segment support grid.

[0024] According to the stent described in some embodiments of the present specification, the distal segment support frame includes a first distal segment support grid and a second distal segment support grid; the first distal segment support grid is arranged below a curved rod in the first leaflet fixing assembly and a curved rod in the second leaflet fixing assembly; the second distal segment support grid is arranged below another curved rod in the first leaflet fixing assembly and another curved rod in the second leaflet fixing assembly; and a resistance film is fixed on the first distal segment support grid and the second distal segment support grid, respectively, and the material of the resistance film includes a polymer material and / or a biogenic material.

[0025] According to the stent described in some embodiments of the present specification, the first distal segment support grid has a first W-shaped frame, and the second distal segment support grid has a second W-shaped frame; the connection points of the two curved rods in the first leaflet fixing assembly are respectively connected to one end of the first W-shaped frame and one end of the second W-shaped frame through a first positioning rod; the connection points of the two curved rods in the second leaflet fixing assembly are respectively connected to the other end of the first W-shaped frame and the other end of the second W-shaped frame through a second positioning rod; the W-shaped frame includes more than one triangular sub-grid and / or more than one quadrilateral sub-grid.

[0026] According to the stent described in some embodiments of the present specification, the proximal segment support frame is an inverted table body, and the distal segment support frame is an upright table body. The maximum radial dimension of the upper base of the inverted table body is greater than the maximum radial dimension of the lower base, and the maximum radial dimension of the upper base of the upright table body is smaller than the maximum radial dimension of the lower base.

[0027] According to the bracket described in some embodiments of this specification, the minimum upper base angle of the inverted platform is smaller than the minimum lower base angle of the upright platform.

[0028] According to the bracket described in some embodiments of this specification, the angle of the minimum upper base angle of the inverted body is within the numerical range of 75° to 85°, and the angle of the minimum lower base angle of the upright body is within the numerical range of 80° to 87°.

[0029] According to the stent described in some embodiments of the present specification, the number of the leaflet fixing assembly is 1, and the stent also includes a fixing accessory; the fixing accessory is connected between the proximal segment support frame and the distal segment support frame, and is arranged opposite to the leaflet fixing assembly in the circumferential direction of the stent.

[0030] According to the stent described in some embodiments of the present specification, the leaflet fixing assembly includes two curved rods connected in a V-shaped structure; the connection point of the two curved rods is connected to the distal segment support frame, and the external end points of the two curved rods, each away from the connection point, are respectively connected to the proximal segment support frame; the fixing attachment has the same structure as the leaflet fixing assembly.

[0031] According to the stent described in some embodiments of the present specification, the orthographic projection of the pocket-shaped support rod on the axial cross-section of the stent is located between the orthographic projections of the two curved rods in the leaflet fixing assembly on the axial cross-section of the stent.

[0032] According to the stent described in some embodiments of the present specification, the radial size of the rods constituting the leaflet fixing assembly is larger than the radial size of the rods constituting the remaining parts of the stent, so that when the stent is expanded in the blood vessel, the contact surface per unit length of the rods constituting the leaflet fixing assembly with the blood vessel is larger than the contact surface per unit length of the rods constituting the remaining parts with the blood vessel; the remaining parts include one or more of the following parts: the proximal segment support frame, the pocket-shaped support rod, and the distal segment support frame.

[0033] According to the stent described in some embodiments of the present specification, the radial dimension of the rods constituting the leaflet fixing assembly is n times the radial dimension of the rods constituting the remaining parts, wherein 1<n≤2.

[0034] According to the stent described in some embodiments of the present specification, the radial dimension of the rods constituting the leaflet fixing assembly is 0.1 mm to 0.5 mm.

[0035] One or more embodiments of the present specification also provide an artificial venous valve, comprising a leaflet and any one of the aforementioned stents; the leaflet is fixedly disposed on the leaflet fixing assembly.

[0036] According to the artificial venous valve described in some embodiments of the present specification, the leaflet has a fixed edge, and the fixed edge of the leaflet is fixed on two curved rods connected in a V-shaped structure in the leaflet fixing component; the leaflet also has a free edge, and the free edge of the leaflet is located between the two ends of the fixed edge of the leaflet.

[0037] According to the artificial venous valve described in some embodiments of the present specification, the leaflet also has a first leaflet ear, a second leaflet ear and a positioning portion; the first leaflet ear and the second leaflet ear of the leaflet are respectively fixed at the first positioning ear and the second positioning ear, and the positioning portion of the leaflet is fixed at the positioning rod connected to the connection points of two curved rods in the corresponding leaflet fixing assembly.

[0038] According to the artificial venous valve described in some embodiments of this specification, the free edge of the leaflet is an arc-shaped edge convex toward its fixed edge. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] This specification will be further explained by way of exemplary embodiments, which will be described in detail by way of the accompanying drawings. The same numbers in the drawings represent the same structures or steps.

[0040] Figure 1It is a stereoscopic view of an artificial venous valve according to some embodiments of the present specification.

[0041] Figure 2 It is a cut mesh surface of a stent according to some embodiments of the present specification.

[0042] Figure 3 is a first side view of a bracket according to some embodiments of the present specification.

[0043] Figure 4 is a second side view of the bracket shown in some embodiments of the present specification.

[0044] Figure 5 It is a schematic diagram of the structure of the S-shaped portion shown in some embodiments of this specification.

[0045] Figure 6 It is a schematic diagram of the structure of the V-shaped support legs and the pocket-shaped support rods shown in some embodiments of this specification.

[0046] Figure 7 yes Figure 6 Side view of.

[0047] Figure 8 It is a schematic diagram of the structure of the leaflet fixing assembly shown in some embodiments of the present specification.

[0048] Fig. 9 It is a schematic diagram of the structure of the curved rod in the leaflet fixing assembly shown in some embodiments of the present specification.

[0049] Fig.10 1 is a first side view of a proximal segment support frame according to some embodiments of the present specification.

[0050] Fig.11 is a second side view of the proximal segment support frame shown in some embodiments of the present specification.

[0051] Fig.12 is a first side view of a distal segment support frame according to some embodiments of the present specification.

[0052] Fig.13 is a second side view of the distal segment support frame shown in some embodiments of the present specification.

[0053] Fig.14 It is a second side view of the bracket shown in other embodiments of the present specification.

[0054] Fig.15 is a side profile view of a bracket according to some embodiments of the present specification.

[0055] Fig.16It is a cutting mesh surface of a bracket shown in other embodiments of this specification.

[0056] Fig.17 It is a schematic diagram of leaflets according to some embodiments of the present specification.

[0057] Fig.18 This is a diagram of a first state of an artificial venous valve in a venous vessel according to some embodiments of the present specification.

[0058] Fig.19 This is a second state diagram of the artificial venous valve in the venous blood vessel according to some embodiments of the present specification.

[0059] Figure 20 to Figure 22 2 are diagrams showing different states of leaflets according to some embodiments of the present specification.

[0060] Fig.23 It is a schematic diagram of the structure of an artificial venous valve according to other embodiments of the present specification.

[0061] Fig.24 yes Fig.23 Diagram showing the state of the artificial venous valve in the venous blood vessel.

[0062] Markings in the figure: 1 proximal segment support frame; 11 V-shaped support foot; 12 proximal segment support grid; 121 V-shaped frame; 122 support rod; 2 leaflet fixing assembly; 21, 22 curved rods; 211, 212 arc-shaped parts; 23, 24 external end points; 25 connection point; 3 pocket-shaped support rod; 31 S-shaped part; 32 straight rod; 33 farthest point; 4 distal segment support frame; 41 distal segment support grid; 411 W-shaped frame; 412 support rod; 5 leaflet; 51 fixed edge; 52 free edge 53 first leaflet ear; 54 second leaflet ear; 55 positioning part; 56 interleaflet opening; 57 leaflet fitting area; 6 positioning ear; 61 positioning hole; 7 positioning rod; 8 inhibitory membrane. DETAILED DESCRIPTION

[0063] In order to more clearly illustrate the technical solutions of the embodiments of this specification, the embodiments will be described in detail below with reference to the accompanying drawings. Obviously, the contents described below are some examples or embodiments of this specification. For ordinary technicians in this field, without paying creative work, the technical solutions or means disclosed in this specification can also be applied to other scenarios based on these technical contents.

[0064] Unless otherwise specified, technical terms used in this specification to describe components, elements, etc. do not refer to the singular, but may also include the plural. Generally speaking, terms such as "include", "comprise", etc. only indicate that the steps, elements, or components that have been clearly identified are included, and these steps, elements, and components do not constitute an exclusive list, such as the method or device described may also include other steps or components.

[0065] An artificial venous valve (hereinafter referred to as an artificial valve) generally consists of a stent and a leaflet, and the leaflet is fixed on the stent. The stent needs to have good support to ensure that the leaflets can be effectively fixed in the blood vessel. Its material can include metal materials, polymer materials and biomaterials, among which metal materials can include metal tantalum, medical stainless steel and nickel-titanium alloy. The stent can have a folded state and an open state. Before the artificial venous valve is implanted in the venous blood vessel, the stent is in a folded state so as to be compressed into the inside of the catheter sheath. The artificial venous valve then enters the venous blood vessel through the catheter. When it reaches the implantation target position, the stent is supported. Thereafter, the artificial venous valve supports the blood vessel at the implantation target position and replaces the native venous valve. In some embodiments, when the stent is expanded, the proximal side of the leaflet (i.e., the side of the leaflet facing the heart after the artificial valve is implanted in the venous blood vessel) can form a pocket-shaped space (or be understood as the stent bulging along the radial direction of the blood vessel away from the center of the blood vessel), and then the blood flow can form a bypass in the pocket-shaped space to prevent venous blood from stagnating in the angle area between the leaflet and the blood vessel wall and forming a thrombus. In order to facilitate the stent to fully expand in the blood vessel, on the other hand, the material of the stent needs to have a certain elasticity or flexibility. Therefore, how to make the stent have good support and flexibility at the same time is a problem worth studying.

[0066] To this end, some embodiments of this specification propose a bracket that satisfies both support and deformation requirements through structural improvements.

[0067] It should be noted that, unless otherwise specified, the structural features of the bracket described in some embodiments of this specification are applicable to both the supporting state and the folded state.

[0068] Figure 1 1 is a three-dimensional diagram of an artificial venous valve according to some embodiments of the present specification, which shows the structure of the artificial venous valve when the stent is expanded. Figure 1As shown, some embodiments of the present specification provide an artificial venous valve stent and leaflets 5, wherein the stent further includes a proximal segment support frame 1, a leaflet fixing assembly 2, a pocket-shaped support rod 3 and a distal segment support frame 4. The proximal segment refers to a section of the stent close to the heart after the artificial valve is implanted in a venous vessel, and the distal segment refers to a section away from the heart. The leaflet fixing assembly 2 is connected between the proximal segment support frame 1 and the distal segment support frame 4 to fix the leaflets. The pocket-shaped support rod 3 is arranged along the axial direction of the stent, with a first end connected to the proximal segment support frame 1, and a second end connected to the distal segment support frame 4. In order to facilitate the distinction of different components of the stent from the figure, Figure 1 The dotted lines are used to illustrate the connection between the proximal segment support frame 1 and the leaflet fixing assembly 2 and the pocket-shaped support rod 3, and the double-dotted lines are used to illustrate the partial connection between the distal segment support frame 1 and the leaflet fixing assembly 2 and the pocket-shaped support rod 3. Figure 1 The leaflets 5 of the artificial venous valve shown are of a bi-leaflet symmetrical design. When the artificial venous valve is placed in a blood vessel, the circumference of the stent is wrapped by the blood vessel wall, and the two leaflets 5 form a one-way valve in the axial direction of the blood vessel, which opens and closes periodically with the flow of blood.

[0069] In some embodiments, the stent can be formed by laser cutting a tube made of a corresponding material. As an example, the structural "pattern" of the stent can be designed on a computer device, and the stent can be cut on the tube by laser printing technology to obtain a stent in a collapsed state. Figure 2 According to the cutting mesh of the stent shown in some embodiments of this specification, the cut pipe can be cut and flattened along the longitudinal direction to obtain Figure 2 The status shown. Figure 1 akin, Figure 2 The dotted line is used to illustrate the connection between the proximal support frame 1, the leaflet fixing assembly 2 and the pocket-shaped support rod 3, and the double-dotted line is used to illustrate the connection between the distal support frame 1, the leaflet fixing assembly 2 and the pocket-shaped support rod 3. Figure 2 The cut mesh surface shown is formed into a column with the vertical axis as the central axis, so that the aforementioned folded-up bracket can be obtained.

[0070] contrast Figure 1 and Figure 2It can be seen that when the stent is expanded, the pocket-shaped support rod 3 protrudes in the radial direction away from the central axis of the stent to form a pocket-shaped space on the proximal side of the leaflet fixing assembly 2 (or leaflet 5). After the artificial venous valve is implanted in the blood vessel, on the one hand, blood flow can bypass in the pocket-shaped space to prevent venous blood from stagnating in the angle area between the leaflet and the blood vessel wall and forming a thrombus; on the other hand, the stent will be stressed in its axial direction due to the impact of blood flow, and at the same time, due to the radial pressure from the blood vessel wall, the pocket-shaped support rod may become unstable, and then protrude in the radial direction of the stent toward the central axis of the stent (such as inward folding), eventually causing the artificial valve to become disabled.

[0071] Figure 3 1 is a first side view of a bracket according to some embodiments of the present specification. In some embodiments, the pocket-shaped support rod 3 may include one or more S-shaped portions 31 and straight rods 32 connected in sequence. The S-shaped portion 31 has a larger lateral width than the straight rod 32, which can increase the instability stress threshold to a certain extent and reduce the probability of instability of the pocket-shaped support rod. As an example, the diameter of the straight rod 32 in the pocket-shaped support rod 3 can be 0.3 to 0.5 mm, and the lateral width of the S-shaped portion 31 (e.g. Figure 6 The width D) shown can reach 1-2 mm, which shows that the S-shaped portion 31 can effectively increase the transverse dimension of the pocket-shaped support rod 3. The S-shaped portion 31 can also increase the contact area between the stent and the blood vessel to prevent the artificial valve from shifting under blood pressure.

[0072] In some embodiments, the opening degree of at least one half arc of at least one S-shaped portion is greater than 0. Figure 5 As shown, the semi-arc can be the upper half or lower half of the S-shaped area. A semi-arc can be regarded as a shape composed of two straight lines and the arc between them. The opening of the semi-arc is positively correlated with the angle between the tangents of the two endpoints of the semi-arc. For example, the opening of the semi-arc can be related to Figure 5 The opening of the semi-arc is greater than 0, which means that the two straight lines are not parallel. The larger the opening of the semi-arc is, the greater the rigidity of the S-shaped part is, and the smaller the probability of instability of the pocket-shaped support rod 3 is. Therefore, the local stiffness of the pocket-shaped support rod can be adjusted by changing the opening of the semi-arc of the S-shaped part. In some embodiments, the opening of the semi-arc can be taken from the numerical range [15°, 20°]. In some embodiments, all semi-arcs in one or more S-shaped parts 31 connected in sequence have equal openings, such as Figure 5 In other embodiments, different semi-arcs in one or more S-shaped portions 31 connected in sequence may have different openings, such as Figure 5As shown on the right side, the opening of the upper semi-arc in more than one S-shaped portion 31 can be represented by angle θ1, and the opening of the lower semi-arc can be represented by angle θ2, wherein angle θ1 is smaller than angle θ2. Specifically, the opening of the semi-arc near the distal segment support frame 4 in the stent is greater than the opening of the semi-arc near the proximal segment support frame 1. In this way, when the stent is expanded, the part of the pocket-shaped support rod 3 near the distal segment support frame 4 has greater strength. Even if the part near the proximal segment support frame 1 is unstable and folded inward to a certain extent, the stent can still form a larger pocket-shaped space in the area near the proximal side of the leaflet 5, ensuring that the blood can form a turbulent flow, thereby reliably reducing the probability of thrombus formation.

[0073] In some embodiments, one or more S-shaped portions 31 connected in sequence may include an even number of semi-arcs, such as 2, 4, etc. In other embodiments, one or more S-shaped portions 31 connected in sequence may also include an odd number of semi-arcs, such as 3, 5, etc.

[0074] Fig.10 is a first side view of the proximal segment support frame shown in some embodiments of this specification. Figure 3 as well as Fig.10 In some embodiments, the proximal support frame 1 includes a V-shaped support foot 11 corresponding to the pocket-shaped support rod 3. Specifically, the V-shaped support foot 11 can correspond to the pocket-shaped support rod 3 one by one. Figure 2 In the cutting mesh, the V-shaped support legs 11 are gathered into two parallel sides. When the support is expanded, the V-shaped support legs 11 are expanded in a V shape. By adjusting the size of each part of the proximal support frame 1, the V-shaped opening of the V-shaped support legs 11 when the support is expanded can be adjusted. The V-shaped opening is positively correlated with the angle between the two sides forming the V-shaped structure. Figure 2 and Figure 3 As shown, the first end (specifically the proximal end) of the pocket-shaped support rod 3 is connected to the corresponding V-shaped support foot 11 of the proximal section support frame 1.

[0075] It is understandable that the larger the V-shaped opening of the V-shaped support leg, the larger its lateral size, and the greater the rigidity or mechanical strength of the V-shaped support leg. Therefore, when the bracket is opened, the V-shaped support leg 11 can further increase the rigidity of the pocket-shaped support rod 3 to avoid inward folding. In some embodiments, the V-shaped opening of the V-shaped support leg is greater than a set threshold. For example, the aforementioned set threshold can be between 30° and 60°, and specifically can be 35°, 40°, 45°, 50°, 55°, etc.

[0076] Figure 4 is a second side view of the bracket shown in some embodiments of the present specification. Figure 6 1 is a schematic diagram of the structure of the V-shaped support foot and the pocket-shaped support rod according to some embodiments of this specification. Figure 4 and Figure 6 As shown, when the stent is expanded, the V-shaped support foot 11 and the pocket-shaped support rod 3 bulge in a direction away from the central axis of the stent, making the side profile of the support look like a waist drum structure. The V-shaped support foot 11 can provide better drum-shaped support force to prevent the pocket-shaped support rod 3 from bending inward after being compressed by the blood vessel. It can be understood that the height of the connection point between the V-shaped support foot 11 and the pocket-shaped support rod 3 in the axial direction of the stent is related to the V-shaped opening of the V-shaped support foot 11. When the V-shaped opening is larger, the axial height of the connection point between the two is lower, thereby shortening the length of the pocket-shaped support rod 3 and increasing the support stiffness. Therefore, by adjusting the height position of the aforementioned connection point in the axial direction of the stent, the support stiffness of the pocket-shaped space can be changed, so that the stent can expand the blood vessel more effectively while reducing the support force, thereby reducing damage to the blood vessel. As mentioned above, the structural design of the S-shaped portion can also increase the support stiffness and prevent inward folding. In some embodiments, the distance between the upper end points of the two sides of the V-shaped support foot to the connection point of the two sides can be used as the length of the V-shaped support foot, such as Figure 6 When the bracket is extended, the length of the V-shaped support leg 11 is less than the total length h2 of the more than one S-shaped portion 31 connected in sequence in the pocket-shaped support rod 3. Figure 2 , Figure 3 as well as Figure 6 In some embodiments, one or more S-shaped portions 31 connected in sequence in the pocket-shaped support rod 3 are connected to the distal segment support frame 4 through a straight rod 32, that is, the straight rod 32 is between the S-shaped portion of the pocket-shaped support rod 3 and the second end of the pocket-shaped support rod 3. The S-shaped portion can have a better structural transition through the straight rod to connect with the distal segment support frame. In some embodiments, the total length h2 of the one or more S-shaped portions 31 connected in sequence is greater than the length h3 of the straight rod 32. Experiments have shown that the length relationship between the V-shaped support foot, the S-shaped portion and the straight rod can make the pocket-shaped support rod easy to open, and at the same time have better support stiffness after opening.

[0077] Figure 7 for Figure 6 When the stent is expanded, the pocket-shaped support rod resembles an arch, and the arch has a distance from the central axis of the stent (such as Figure 7 The farthest point is shown by the dashed line in the middle. Let this point be Figure 7The farthest point 33 in the bracket, the distance from the farthest point 33 to the central axis of the bracket is r1. As mentioned above, the height of the connection point between the V-shaped support foot 11 and the pocket-shaped support rod 3 in the axial direction of the bracket is related to the V-shaped opening of the V-shaped support foot 11. When the V-shaped opening is larger, the axial height of the connection point between the two is lower. Therefore, it can be understood that the V-shaped opening of the V-shaped support foot 11 is related to the height of the farthest point 33 in the axial direction of the bracket. At the same time, the V-shaped opening of the V-shaped support foot 11 will affect the length of the V-shaped support foot 11. Therefore, in some embodiments, the height of the farthest point 33 in the axial direction of the bracket is also related to the length of the V-shaped support foot 11. In this way, when designing the cutting mesh of the bracket, by adjusting the length of the two sides of the V-shaped support foot 11, the V-shaped opening and / or length of the V-shaped support foot 11 when the bracket is opened can be adjusted, thereby adjusting the height of the farthest point 33 in the axial direction of the bracket.

[0078] In some embodiments, when the stent is expanded, the height of the farthest point 33 in the axial direction of the stent is equal to the height of the connection point between the leaflet fixing assembly 2 and the proximal segment support frame 1 on the stent axis. In other embodiments, when the stent is expanded, the farthest point 33 is closer to the distal segment support frame 4 in the axial direction of the stent relative to the connection point between the leaflet fixing assembly 2 and the proximal segment support frame 1. The point on the pocket-shaped support rod that is farthest from the central axis of the stent is offset relative to the distal segment support frame along the axial direction of the stent, which can further ensure that a larger pocket-shaped space is formed in the area close to the proximal side of the leaflet 5, so that the blood can form a turbulent flow.

[0079] Figure 8 Schematic diagram of the structure of the leaflet fixing assembly according to some embodiments of the present specification. Figure 1 , Figure 3 as well as Figure 8 In some embodiments, the leaflet fixing assembly 2 may include a curved rod 21 and a curved rod 22 connected in a V-shaped structure, the connection point 25 of the two curved rods is connected to the distal segment support frame 4, the external end point 23 of the curved rod 21 away from the aforementioned connection point is connected to the proximal segment support frame 1, and the external end point 24 of the curved rod 22 away from the aforementioned connection point is connected to the proximal segment support frame 1. The curved rod in the leaflet fixing assembly 2 is the junction of the leaflet and the stent. For example, the leaflet can be sutured to the curved rod by sutures. The two curved rods are symmetrically designed to present a V-shaped structure in space. When the artificial valve is opened in the venous blood vessel, the curved rod in the leaflet fixing assembly can fit the blood vessel, and combined with the leaflet, it can play an axial sealing role to prevent blood from leaking sideways at the fixed edge of the leaflet.

[0080] In some embodiments, the curved rod may have more than two arc-shaped portions, specifically, may have 2, 3, or more arc-shaped portions. In some embodiments, a reference plane may be determined, and the connection point 25, the external end point 23, and the external end point 24 in the leaflet fixing assembly are located in the reference plane, that is, the reference plane may be determined by the three points. Different arc-shaped portions in the curved rod may be distributed on different sides of the reference plane. Fig. 9 1 is a schematic diagram of the structure of the curved rod in the leaflet fixing assembly according to some embodiments of the present specification. Figure 1 , Figure 4 as well as Fig. 9 , taking the curved rod 21 as an example, the curved rod 21 has an arc portion 211 and an arc portion 212, Fig. 9 The dotted line in represents the projection line of the reference plane, the arc portion 211 is located at the lower side of the reference plane, and the arc portion 212 is located at the upper side of the reference plane.

[0081] Combination Figure 1 or Figure 4 It is not difficult to see that the upper side of the reference plane is also the proximal side, and the lower side is also the distal side. In some embodiments, among the two or more arc-shaped portions of the curved rod, the arc-shaped portion close to the distal segment support frame (such as arc-shaped portion 242) is located on the upper side of the reference plane, that is, the proximal side. With such a design, a certain creep margin can be left for the leaflets on the support structure to extend the service life of the artificial valve. For more information about the influence of creep, please refer to the subsequent description of the leaflets. As an example, Fig. 9 The arc portion 212 shown is closer to the distal segment support frame and is located on the proximal side of the reference plane, while the arc portion 211 away from the distal segment support frame is located on the distal side of the reference plane.

[0082] like Figure 1 as well as Figure 4 As shown, in some embodiments, the number of the leaflet fixing components 2 is 2, and they are arranged opposite to each other in the circumferential direction of the stent, and the leaflets on the two leaflet fixing components can form a one-way valve structure in the axial direction of the blood vessel. In some embodiments, the pocket-shaped support rod can correspond to the leaflet fixing component one by one, see Figure 3 , the orthographic projection of the pocket-shaped support rod on the axial section of the stent is located between the orthographic projections of the two curved rods in the corresponding leaflet fixing assembly on the axial section of the stent. In this way, when the stent is expanded, a pocket-shaped space can be formed above the proximal side of each leaflet fixing assembly. In other embodiments, the number of pocket-shaped support rods can be more, such as one leaflet fixing assembly can correspond to more than two pocket-shaped support rods, and more pocket-shaped support rods can, to a certain extent, better support the pocket-shaped space for the leaflet fixing assembly. Continue to see Figure 1 and Figure 4For any one of the two groups of pocket-shaped support rods and leaflet fixing assemblies, the orthographic projection of the pocket-shaped support rod on the axial section of the stent is located in the middle of the orthographic projections of the two curved rods in the leaflet fixing assembly on the axial section of the stent, and the pocket-shaped space supported by the pocket-shaped support rod for the leaflet fixing assembly is more symmetrical and uniform.

[0083] In addition to the V-shaped support feet for connecting the pocket-shaped support rods, the proximal segment support frame also includes a proximal segment support grid for connecting the leaflet fixing assembly. Fig.11 It is a second side view of the proximal segment support frame shown in some embodiments of the present specification. The proximal segment support grid 12 may have a V-shaped frame 121, and a plurality of struts 122 are fixedly connected in the V-shaped frame 121 to form one or more quadrilateral sub-grids in the V-shaped frame 121. In other embodiments, a greater number of struts 122 may be arranged in the V-shaped frame 121 to form a plurality of triangular sub-grids. It is not difficult to understand that in some other embodiments, the arrangement positions of the struts 122 may be flexibly arranged to form at least one quadrilateral sub-grid and at least one triangular sub-grid in the V-shaped frame 121. The presence of the sub-grid may increase the support stiffness of the V-shaped frame 121, so that the proximal segment support grid 12 may support the blood vessels on the one hand, and may withstand the pressure of the blood flow on the leaflets when the leaflets are closed on the other hand. In some embodiments, the density of the sub-grid is positively correlated with the support stiffness, and the number of sub-grids in the V-shaped frame 121 may be adjusted according to factors such as the weight of the valve fixing assembly.

[0084] In some embodiments, the V-shaped opening of the V-shaped frame 121 may be less than or equal to a set threshold value, and the set threshold value may be between 30° and 60°, specifically 35°, 40°, 45°, 50°, 55°, etc. In some embodiments, the V-shaped frame 121 and the V-shaped support leg 11 may correspond to the same set threshold value, that is, in some embodiments, the V-shaped opening of the V-shaped frame 121 may not be greater than the V-shaped opening of the V-shaped support leg 11. As mentioned above, the support stiffness of the V-shaped structure may be positively correlated with the V-shaped opening. In order to form a larger pocket-shaped space with the pocket-shaped support rod, the V-shaped support leg 11 needs to have a larger support stiffness and deformation space. Therefore, its V-shaped opening may be appropriately increased to improve the support stiffness. At the same time, the simple frame structure of the V-shaped support leg 11 may give it a larger deformation space. Due to the limitation of the overall structure or size of the bracket, the V-shaped frame 121 may have a smaller V-shaped opening, and at the same time, its support stiffness is improved by a number of subgrids in the V-shaped frame 121. Of course, in the specific implementation process, sub-grids can also be set in the V-shaped supporting feet according to actual conditions, and the size, shape and density of the sub-grids can also be changed.

[0085] The proximal segment support grid can be connected to the external end point of the curved rod. Specifically, the same segment support grid can be connected to the external end point of the curved rod in different leaflet fixing assemblies. In other words, the external end points of the two curved rods in the same leaflet fixing assembly are respectively connected to different proximal segment support grids. In this way, the V-shaped support feet and the proximal segment support grids can be alternately distributed in the proximal segment support frame along the axial direction of the stent, providing support to the leaflet fixing assembly and the pocket-shaped support rod, respectively.

[0086] Continuing with the example of a double-leaflet artificial valve, the number of leaflet fixing components is 2, and they are arranged relatively in the circumferential direction of the stent. Correspondingly, the number of proximal segment support grids is also 2. The external end point of a curved rod in the first leaflet fixing component and the external end point of a curved rod in the second leaflet fixing component are both connected to the first proximal segment support grid. The external end point of another curved rod in the first leaflet fixing component and the external end point of another curved rod in the second leaflet fixing component are both connected to the second proximal segment support grid.

[0087] See also Figure 4 In some embodiments, a positioning ear 6 is further connected between the external end point of the curved rod of the leaflet fixing assembly and the proximal support grid 12. Fig. 9 As shown, in some embodiments, the positioning ear 6 may be provided with more than one positioning hole 61, and the positioning hole 61 is used to fix the leaflet. For example, the corresponding part of the leaflet (such as the leaflet ear of the leaflet) can be fixed in the positioning hole by sutures. In some embodiments, the positioning ear can also be regarded as a part of the leaflet fixing assembly. Taking a double-leaflet artificial valve as an example, the external end point of a curved rod in the first leaflet fixing assembly and the external end point of a curved rod in the second leaflet fixing assembly are both connected to the first positioning ear, and the first positioning ear is connected to the first proximal segment support grid; the external end point of another curved rod in the first leaflet fixing assembly and the external end point of another curved rod in the second leaflet fixing assembly are both connected to the second positioning ear, and the second positioning ear is connected to the second proximal segment support grid. As shown Figure 4 As shown, two positioning holes can be set on the positioning ear 6 along the axial direction of the stent, so as to achieve double fixation of the corresponding parts of the leaflet and prevent the leaflet from shifting to the distal segment due to blood flow pressure.

[0088] The distal end support grid is used to support the distal end blood vessel. In some embodiments, the distal segment support frame may have a grid structure. Fig.12 and Fig.13 The structure of the distal support frame is shown from the first side and the second side respectively. The distal support frame may include a distal support grid, and the distal support grid may be arranged under the curved rod of the leaflet fixing assembly to support the leaflet fixing assembly.

[0089] Combination Figure 1 , Figure 4 as well as Fig.13 Taking a double-leaflet artificial valve as an example, in some embodiments, a first distal segment support grid is arranged under a curved rod in a first leaflet fixing assembly and a curved rod in a second leaflet fixing assembly that are connected together through external endpoints; a second distal segment support grid is arranged under another curved rod in the first leaflet fixing assembly and another curved rod in the second leaflet fixing assembly.

[0090] Fig.12 The side view of the first distal segment support grid and the second distal segment support grid is shown from the first side. The two distal segment support grids are distinguished by dashed lines in the figure, that is, the two sides of the dashed lines in the figure are side views of different distal segment support grids 41. Fig.13 In some embodiments, the distal segment support grid 41 has a W-shaped frame 411, and the W-shaped frame 411 includes a plurality of struts 412 to form more than one triangular sub-grid and / or more than one quadrilateral sub-grid. For more descriptions of the struts forming sub-grids, please refer to the above descriptions of the proximal segment support grid, which will not be repeated here.

[0091] Fig.14 is a second side view of a bracket according to other embodiments of this specification. Fig.13 as well as Fig.14 As shown, in some embodiments, a barrier film 8 may be fixed on the distal support grid 41. In some embodiments, the material of the barrier film may include a polymer material or a biogenic material, wherein the polymer material may further be polysiloxane, polytetrafluoroethylene, polyurethane or styrene polymer, etc., and the biogenic material may further be porcine pericardium, porcine heart valve, bovine pericardium or bovine heart valve, etc. After the artificial valve enters the blood vessel for a period of time, the biological tissue of the organism (such as the human body) may proliferate and gradually cover the artificial valve. Compared with the metal stent, the biological tissue is more likely to climb onto the leaflet with a closer material property. When the biological tissue proliferates and covers the leaflet, the thickness of the leaflet will increase, and the sensitivity of opening and closing will be affected. The barrier film has a material similar to or the same as the leaflet, which can "drain" at least part of the proliferating biological tissue, thereby hindering or reducing the proliferation of biological tissue on the leaflet and extending the service life of the artificial valve. At the same time, when the biological tissue of the organism proliferates and covers the obstructive membrane, the adhesion between the stent and the blood vessel can be increased, thereby preventing the stent from shifting in the blood vessel and increasing the circumferential sealing of the artificial valve. The grid structure of the distal support grid is more conducive to fixing the obstructive membrane.

[0092] See also Figure 3In some embodiments, the connection point of the two curved rods in the leaflet fixing assembly can be connected to one end of the W-shaped frame through a positioning rod 7. The positioning rod can be used to fix the corresponding part of the leaflet (such as the positioning part of the leaflet). In some embodiments, the positioning rod can be regarded as a part of the leaflet fixing assembly. Figure 1 , Figure 4 as well as Fig.13 Taking a double-leaflet artificial valve as an example, in some embodiments, the connection points of the two curved rods in the first leaflet fixing assembly can be connected to one end of the first W-shaped frame and one end of the second W-shaped frame through the first positioning rod; the connection points of the two curved rods in the second leaflet fixing assembly can be connected to the other end of the first W-shaped frame and the other end of the second W-shaped frame through the second positioning rod. One end of some of the support rods 412 in the W-shaped frame 411 can be connected to the curved rod of the corresponding leaflet fixing assembly to increase stability.

[0093] Fig.15 is a side view of a bracket according to some embodiments of the present specification. Fig.15 As shown, in some embodiments, when the stent is expanded, its proximal section support frame is an inverted platform structure, the pocket-shaped support rod and the leaflet fixing assembly bulge out along the radial direction of the stent away from the central axis to form a pocket-shaped or waist-drum-shaped structure, and the distal section support frame is a positive platform structure. Fig.15 As shown, when the leaflets of the artificial valve are closed (or simply referred to as the artificial valve is closed), blood can flow around the lumbar drum area to prevent blood stasis and thrombosis.

[0094] Generally speaking, the table body can be a portion between the bottom surface and the cross section obtained by cutting the cone with a plane parallel to the bottom surface of the cone, and the table body can be considered to have two bottom surfaces, upper and lower. The cross section of the table body or cone can be of any shape, such as a triangle, a polygon, a circle, an ellipse, and the like. The maximum radial dimension of the upper bottom surface of the inverted table body is greater than the maximum radial dimension of the lower bottom surface, and the maximum radial dimension of the upper bottom surface of the positive table body is less than the maximum radial dimension of the lower bottom surface. Taking the table body with a circular cross section as an example, the diameter of the upper bottom surface of the inverted table body is greater than the diameter of the lower bottom surface, and the diameter of the upper bottom surface of the positive table body is less than the diameter of the lower bottom surface. Taking the table body with an elliptical cross section as an example, the long axis of the upper bottom surface of the inverted table body is greater than the long axis of the lower bottom surface, and the long axis of the upper bottom surface of the positive table body is less than the long axis of the lower bottom surface. It should be noted that in some embodiments of the present specification, unless otherwise specified, "upper" corresponds to the proximal end or proximal side, and "lower" corresponds to the distal end or distal side.

[0095] In some embodiments, when the stent is expanded, the pocket-shaped support rod will bulge further away from the central axis of the stent relative to the leaflet fixing assembly. Accordingly, the proximal segment support frame used to support the above two can be an inverted platform with an elliptical or approximately elliptical cross section, and the distal segment support frame can be an upright platform with an elliptical or approximately elliptical cross section. When the stent is expanded, its proximal segment support frame is an inverted platform structure, which means that the upper end of the proximal segment support frame is in an emitting or opening shape, which can make the upper end closer to the inner wall of the blood vessel while expanding the blood vessel radially to a certain extent. Such a design can effectively prevent the blood pressure from causing the stent to shift axially toward the distal side when the artificial valve is closed, and then reliably fix the stent in the implantation position. Symmetrically, the distal segment support frame of the stent is an upright platform structure, which means that the lower end of the distal segment support frame is in an emitting or opening shape, which can make the lower end of the distal segment support frame closer to the inner wall of the blood vessel while expanding the blood vessel radially to a certain extent. Such a design can effectively prevent the blood impact from causing the stent to shift axially toward the proximal side when the artificial valve is opened. Of course, in general, the larger radial dimensions of the openings at both ends of the stent can better fix the stent in the blood vessel and prevent the stent from shifting axially along the blood vessel.

[0096] The bottom angle can be understood as the angle between the straight line passing through the center of the bottom surface on the bottom surface of the platform and the corresponding generatrix, the upper bottom angle is the angle between the straight line passing through the center of the bottom surface in the upper bottom surface of the platform and the corresponding generatrix, and the lower bottom angle is the angle between the straight line passing through the center of the bottom surface in the lower bottom surface of the platform and the corresponding generatrix. In some embodiments, the minimum upper bottom angle of the inverted platform presented by the proximal segment support frame of the stent is smaller than the minimum lower bottom angle of the positive platform presented by the distal segment support frame. This means that the upper opening size of the proximal segment support frame can be larger than the lower opening size of the distal segment support frame in a certain radial direction. When the artificial valve is closed, the pressure of the blood in the blood vessel on the artificial valve toward the distal end is greater than the pressure of the blood impact on the artificial valve toward the proximal segment when the artificial valve is opened. Therefore, the larger upper opening of the stent can better resist the greater pressure of the blood on the artificial valve toward the distal segment. In some embodiments, the angle of the minimum upper bottom angle of the inverted platform corresponding to the proximal segment support frame is taken from the numerical range of 75° to 85°, and the angle of the minimum lower bottom angle of the cone is taken from the numerical range of 80° to 87°. Taking the cross section of the bracket outer contour as an ellipse as an example, the bottom angle formed by the long axis of the upper bottom surface of the inverted body presented by the proximal section support frame and the generatrix is ​​the minimum upper bottom angle, such as Fig.15 α1 in the figure; the base angle formed by the long axis of the bottom surface of the platform presented by the distal support frame and the generatrix is ​​the minimum bottom angle, such as Fig.15 α2, α1<α2. As an example, the value of α1 may be 82°, and the value of α2 may be 85°.

[0097] As mentioned above, when the artificial valve is stretched in the blood vessel, the leaflet fixing assembly can fit the blood vessel, and the leaflet can seal the blood vessel axially and prevent blood from leaking around the stent. In some embodiments, in order to further improve the sealing performance of the leaflet fixing assembly, the rods constituting the leaflet fixing assembly can have a larger radial dimension, so that the contact surface between the leaflet fixing assembly and the blood vessel wall can be increased, and the sealing effect is better. In some embodiments, the rod can be a basic structural unit constituting the stent, and the radial dimension of the rod can specifically be a radial dimension in a single or multiple directions on the cross section of the rod, such as the width, thickness, diameter, major axis, minor axis, etc. of the rod. For the leaflet fixing assembly 2, the rod can include curved rods 21 and 22. In some embodiments, the rod in the leaflet fixing assembly has a larger dimension in its cross section and in a direction parallel to the contact surface between the rod and the blood vessel wall, so as to achieve the purpose of increasing the contact surface between the rod in the leaflet fixing assembly and the blood vessel wall.

[0098] Fig.16 It is a cutting mesh surface of a stent according to other embodiments of this specification. Figure 2 akin, Fig.16 The dotted line is used to illustrate the connection between the proximal support frame 1, the leaflet fixing assembly 2 and the pocket-shaped support rod 3, and the double-dotted line is used to illustrate the connection between the distal support frame 1, the leaflet fixing assembly 2 and the pocket-shaped support rod 3. In some embodiments, the radial size of the rods constituting the leaflet fixing assembly can be 0.1 mm to 0.5 mm. Fig.16 As an example, the width d1 of the rods constituting the leaflet fixing assembly 1 may be 0.2 mm, 0.3 mm, 0.4 mm, and so on.

[0099] In some embodiments, the radial dimensions of the rods constituting the leaflet fixing assembly are greater than the radial dimensions of the rods constituting the remaining parts of the stent. Among them, the remaining parts of the stent may include one or more of the following parts: a proximal segment support frame, a pocket-shaped support rod, and a distal segment support frame. In some embodiments, for the proximal segment support frame 1, the rods may include rods constituting a V-shaped support foot 11, rods constituting a V-shaped frame 121, and a plurality of support rods 122. For the pocket-shaped support rod 3, the rods may include a bent rod constituting an S-shaped portion 31 and a straight rod 32. For the distal segment support frame 4, the rods may include a rod constituting a W-shaped frame 411 and a support rod 412.

[0100] Continue to see Fig.16In some embodiments, the width d1 of the rods constituting the leaflet fixing assembly is greater than the width of the rods constituting the rest of the stent, and greater than the width d2 of the rods in the proximal segment support frame 1. With such a design, when the stent is expanded in the blood vessel, the contact surface per unit length of the rods constituting the leaflet fixing assembly 1 with the blood vessel is greater than the contact surface per unit length of the rods constituting the rest of the stent. The unit length is introduced for the convenience of comparison. The unit length can be flexibly set according to the specific length of the stent or the stent part. For example, the unit length can be 1mm, 2mm, 1cm, etc. In some embodiments, the radial dimension of the rods constituting the leaflet fixing assembly can be n times the radial dimension of the rods constituting the rest of the stent, where 1<n≤2. For example, n can be 1.2, 1.5, 1.8, etc.

[0101] In some other embodiments, a sealing film is provided around the stent to improve the sealing performance, for example, a sealing film is wrapped around the stent along the circumference of the distal support frame. In contrast, some embodiments of the present specification achieve the purpose of improving the sealing performance by increasing the radial size of the rods constituting the leaflet fixing assembly, thereby eliminating the sealing film and making the structure of the artificial valve more streamlined.

[0102] For artificial valves, the valve leaflets are fixed on the valve leaflet fixing assembly of the stent. The valve leaflets can be made of biogenic materials such as pig pericardium, pig heart valve, bovine pericardium, bovine heart valve, etc., or various polymer materials. Fig.17 Schematic diagram of the leaflets according to some embodiments of this specification. Fig.17 The leaflet 5 is shown in a flat state, and the leaflet 5 has a fixed edge 51. The fixed edge 51 can be used to be fixedly connected to the leaflet fixing assembly. Specifically, the fixed edge 51 of the leaflet 5 is fixed on two curved rods connected in a V-shaped structure in the leaflet fixing assembly, so the fixed edge 51 can have an arc-shaped edge adapted to the curved rod. The leaflet 5 also has a free edge 52, and the free edge 52 is located between the two ends of the fixed edge 51 of the leaflet. The free edge 52 will not be fixedly connected to the leaflet fixing assembly, and it is in an open and free state. In an artificial valve, the free edge 52 of the leaflet will form an opening for blood circulation.

[0103] To further strengthen the leaflets, Fig.17The leaflet 5 shown may further have a first leaflet ear 53, a second leaflet ear 54 and a positioning portion 55. The first leaflet ear 53 and the second leaflet ear 55 are respectively fixed at the first positioning ear and the second positioning ear of the corresponding leaflet fixing assembly in the bracket, and the positioning portion 55 is fixed at the positioning rod connected to the connection point of the two curved rods in the corresponding leaflet fixing assembly. The leaflet ears and the positioning portion also help to improve the suturing efficiency of the leaflets. Specifically, in the process of manufacturing an artificial valve, the leaflet ears on both sides of the leaflet can be first fixed to the positioning ears of the leaflet fixing assembly with sutures, the positioning portion at the bottom of the leaflet is fixed to the positioning rod with sutures, and then the leaflet is sutured to the curved rod along the fixed edge.

[0104] In some embodiments, the corresponding part of the leaflet can be fixed to the leaflet fixing assembly by suturing. There can be a variety of implementations for the suturing of the leaflets. For example, the leaflet suture part can be wrapped around the corresponding part of the leaflet fixing assembly (such as the curved rod, positioning ear, positioning rod, etc.) (referred to as the full-wrap suturing method), or the leaflet suture part can be only attached to the inner surface of the corresponding part of the leaflet fixing assembly (referred to as the half-wrap suturing method). The full-wrap suturing method enables the blood vessels to contact the flexible leaflets, which is more conducive to sealing. The half-wrap suturing method can keep the leaflets away from the blood vessels, prevent the biological tissue in the body from climbing, and avoid the thickening of the leaflets and the failure of the leaflet function.

[0105] The stent and the leaflets form a complete artificial valve. In some embodiments, according to the number of leaflets in the artificial valve, it can be called a single-leaflet valve, a two-leaflet valve, or a three-leaflet valve. The aforementioned embodiments are mainly described by taking the two-leaflet valve as an example. In the two-leaflet valve, the number of leaflet fixing components is 2, and they are arranged relatively in the circumferential direction of the stent. After the leaflets are sutured to the leaflet fixing components, the free edges of the two leaflets cooperate to form a one-way valve port in the artificial valve that allows blood to flow. Fig.18 , 19 The first and second state diagrams of the bileaflet artificial venous valve in the venous blood vessel according to some embodiments of the present specification are respectively shown. Fig.18 In the process, the pressure at the proximal end (the upper end in the figure) is higher than that at the distal end (the lower end in the figure). At this time, the free edges of the two leaflets in the artificial valve fit together and the artificial valve is closed. Fig.19 In the process of blood flow, the pressure at the distal end (lower end in the figure) is higher than that at the proximal end (upper end in the figure). At this time, the free edges of the two leaflets in the artificial valve are separated by the blood, and the artificial valve opens. In this way, the artificial valve can replace the native valve in the venous blood vessel and prevent blood from flowing back.

[0106] Continue to see Fig.17In some embodiments, the free edge 52 of the leaflet 5 is an arc-shaped edge convex toward its fixed edge 51. Such a design can effectively prevent the upper edges of the free edges 52 of the two leaflets from bending backwards and separating due to the large bonding area after the two leaflets are attached together, thereby preventing the valve from closing completely. Figures 20-22 Provide explanation.

[0107] like Fig. 20 As shown on the left, at this time, the pressure at the distal end of the valve is greater than the pressure at the proximal end, and the leaflets are opened by the blood flow to form an opening 56 between the leaflets, and the blood in the venous blood vessels can flow back to the heart. When the pressure at the distal end of the valve further increases, the opening between the leaflets will further increase, as shown in FIG. Fig. 20 As shown on the right. Fig.21 As shown in the figure, the pressure at the proximal end of the valve begins to increase and gradually becomes greater than the pressure at the distal end, at which point the leaflets begin to close. Fig. 22 As shown in FIG. 1 , when the pressure at the proximal end of the valve further increases, the contact area between the two leaflets will shift toward the distal end under the blood pressure from the proximal end. If the free edge 52 of the leaflet is a straight edge, a contact portion is easily formed when the two leaflets are contacted. The contact portion can be located as shown in FIG. Fig.21 , 22 At the leaflet fitting area 57 above the free edge of the leaflet and enclosed by the dotted line, as the pressure at the proximal end of the valve further increases, the area of ​​the fitting part will further increase, which may eventually cause the upper edges of the straight free edges of the two leaflets to bend back and separate, resulting in incomplete valve closure, i.e. Fig. 22 The situation shown on the right side from the side of the two leaflets, the two arc-shaped dotted lines respectively represent the lateral contours of the two leaflets. At this time, the blood at the proximal end of the valve is prone to backflow, causing the artificial valve to fail. If the free edge 52 of the leaflet is designed to be an arc-shaped edge convex to its fixed edge 52, the area of ​​the leaflet fitting portion can be effectively reduced, avoiding the back bending of the free edge, and improving the reliability of the artificial valve. Experimental data show that when the blood pressure in the venous blood vessel is between 3mmHg and 300mmHg, the leaflets provided in some embodiments of the present specification will not bend back in the artificial valve.

[0108] Some embodiments of the present specification also provide a single-leaflet artificial valve. Fig.23The stent of a single-leaflet artificial valve includes a proximal segment support frame, a leaflet fixing assembly, a fixing accessory, a pocket-shaped support rod and a distal segment support frame. The leaflet fixing assembly is connected between the proximal segment support frame and the distal segment support frame, and is used to fix the leaflet. The fixing accessory is connected between the proximal segment support frame and the distal segment support frame, and is arranged opposite to the leaflet fixing assembly in the circumferential direction of the stent. The pocket-shaped support rod is arranged axially along the stent, the first end of the pocket-shaped support rod is connected to the proximal segment support frame, and the second end thereof is connected to the distal segment support frame. When the stent is expanded, the pocket-shaped support rod can protrude in a direction away from the central axis of the stent along the radial direction of the stent to form a pocket-shaped space on the proximal side of the leaflet fixing assembly.

[0109] contrast Figure 1 as well as Figure 4 It is not difficult to see that the single-leaflet artificial valve stent provided in some embodiments of the present specification has been partially simplified on the double-leaflet artificial valve stent. Specifically, the single-leaflet artificial valve stent only contains a single leaflet fixing component. In order to ensure the supporting effect of the stent, one of the leaflet fixing components in the double-leaflet artificial valve stent can be used as a fixed accessory. Its structure is the same as the leaflet fixing component, except that the leaflet is no longer fixed on it. Correspondingly, in the single-leaflet artificial valve stent, the pocket-shaped support rod is also only arranged at the leaflet fixing component. Specifically, the position of the pocket-shaped support rod can make its positive projection on the axial section of the stent located between the positive projections of the two curved rods in the leaflet fixing component on the axial section of the stent. For the specific structure or construction of the proximal segment support frame, leaflet fixing component, fixing accessory, pocket-shaped support rod and distal segment support frame in the single-leaflet artificial valve stent, please refer to the description of the aforementioned embodiment, which will not be repeated here.

[0110] Fig.24 yes Fig.23 The state diagram of the artificial venous valve in the venous blood vessel shown. A single leaflet forms a one-way valve with the opposite blood vessel wall. When the pressure at the proximal end of the valve is less than the pressure at the distal end, the leaflet 5 separates from the opposite blood vessel wall, and the blood in the venous blood vessel flows back to the heart. When the pressure at the proximal end of the valve is greater than the pressure at the distal end, the pocket-shaped space at the proximal side of the leaflet 5 is filled with blood. The leaflet 5 expands and fills toward the distal end under the pressure of the blood. At this time, the free edge of the leaflet 5 fits against the blood vessel wall, and the artificial valve is closed.

[0111] It should be understood that although the embodiments of this specification mainly describe two-leaflet and single-leaflet artificial valves, based on the principles and structural descriptions of the embodiments of this specification, those skilled in the art will be able to apply the relevant features to three-leaflet or other artificial valves. Therefore, this part of the modified embodiments obtained by transferring the features of the embodiments of this specification still falls within the scope of disclosure of this specification.

[0112] The beneficial effects that may be brought about by the embodiments of this specification include but are not limited to: (1) The pocket-shaped support rod enables the stent to form a pocket-shaped space at the proximal end of the leaflet when it is expanded, and blood can effectively flow around in the pocket-shaped space to prevent blood stasis and thrombus formation; (2) The pocket-shaped support rod has both deformation flexibility and good support, which prevents the stent from becoming unstable and folding inward when it is expanded in the blood vessel; (3) The platform structure of the proximal and distal support frames in the stent can further strengthen the support of the artificial valve in the blood vessel and prevent the artificial valve from shifting under blood pressure; (4) The curved rod design in the leaflet fixing assembly can compensate for the deformation of the leaflet due to long-term use, effectively extending the service life of the valve; (5) The arc of the free edge of the leaflet The edge structure can prevent the formation of a large contact area with other leaflets under high pressure in the proximal segment, thereby causing separation between the leaflets at the free edge, which will lead to valve failure; (6) The sub-grid design in the proximal segment support frame or the distal segment support frame helps to increase the support force of the leaflet fixing assembly; (7) The V-shaped support foot design in the proximal segment support frame can conveniently adjust the height of the point on the pocket-shaped support rod farthest from the central axis of the stent in the axial direction of the stent by adjusting the V-shaped opening of the V-shaped support foot; (8) The point on the pocket-shaped support rod farthest from the central axis of the stent is offset or close to the distal segment support frame along the axial direction of the stent, thereby ensuring that a large pocket-shaped space is reliably formed in the area close to the proximal side of the leaflet, so that the blood can form a turbulent flow. It should be noted that different embodiments may produce different beneficial effects. In different embodiments, the beneficial effects that may be produced may be any one or a combination of the above, or any other beneficial effects that may be obtained. The above only lists the beneficial effects of some embodiments of this specification. The beneficial effects of more technical features of the embodiments of this specification can be found in the relevant description of the corresponding embodiments, and are not listed one by one here.

[0113] The basic concepts have been described above. Obviously, for those skilled in the art, the above detailed disclosure is only for example and does not constitute a limitation of this specification. Although not explicitly stated here, those skilled in the art may make various modifications, improvements and corrections to this specification. Such modifications, improvements and corrections are taught in this specification, so such modifications, improvements and corrections still belong to the spirit and scope of the exemplary embodiments of this specification.

Claims

1. A stent, used in an artificial venous valve, characterized in that: It includes a proximal segment support frame, a leaflet fixing assembly, a pocket-shaped support rod and a distal segment support frame; The leaflet fixing assembly is connected between the proximal segment support frame and the distal segment support frame, and is used to fix the leaflet; The first end of the pocket-shaped support rod is connected to the proximal segment support frame, and the second end of the pocket-shaped support rod is connected to the distal segment support frame; when the stent is expanded, the pocket-shaped support rod can protrude along the radial direction of the stent away from the central axis of the stent to form a pocket-shaped space on the proximal side of the leaflet fixing assembly.

2. The bracket according to claim 1, characterized in that: The pocket-shaped support rod includes more than one S-shaped parts connected in sequence, wherein the opening of at least one semi-arc of at least one S-shaped part is greater than 0, and the opening of the semi-arc is positively correlated with the angle between the tangents of the two endpoints of the semi-arc.

3. The bracket according to claim 1 or 2, characterized in that: The number of the pocket-shaped support rods is more than two; the proximal section support frame includes more than two V-shaped support feet respectively connected to the more than two pocket-shaped support rods; when the support is opened, the V-shaped opening of the V-shaped support feet is greater than a set threshold, and the V-shaped opening is positively correlated with the angle between the two sides forming the V-shaped structure; The first end of the pocket-shaped support rod is connected to the corresponding V-shaped support foot.

4. The bracket according to claim 3, characterized in that: When the bracket is expanded, the length of the V-shaped support leg is less than the total length of more than one S-shaped portion connected in sequence in the pocket-shaped support rod.

5. The bracket according to claim 2, characterized in that: A straight rod is provided between the S-shaped portion of the pocket-shaped support rod close to the distal section support frame and the second end of the pocket-shaped support rod; The total length of the more than one S-shaped parts connected in sequence in the pocket-shaped support rod is greater than the length of the straight rod.

6. The bracket according to claim 2 or 5, characterized in that: In the one or more S-shaped parts connected in sequence in the pocket-shaped support rod, the opening degree of the semi-arc close to the distal segment support frame is greater than the opening degree of the semi-arc close to the proximal segment support frame.

7. The bracket according to claim 3, characterized in that: When the stent is expanded, the height of the point on the pocket-shaped support rod that is farthest from the central axis of the stent along the radial direction of the stent, in the axial direction of the stent, is related to the V-shaped opening and / or length of the V-shaped support foot.

8. The bracket according to claim 1 or 7, characterized in that: When the stent is expanded, the point on the pocket-shaped support rod that is farthest from the central axis of the stent in the radial direction of the stent is at the same height as the connection point between the leaflet fixing assembly and the proximal segment support frame in the axial direction of the stent; Alternatively, when the stent is expanded, the point on the pocket-shaped support rod that is farthest from the central axis of the stent along the radial direction of the stent is closer to the distal segment support frame relative to the connection point between the leaflet fixing assembly and the proximal segment support frame in the axial direction of the stent.

9. The bracket according to claim 1, characterized in that: The leaflet fixing assembly includes two curved rods connected in a V-shaped structure; the connection point of the two curved rods is connected to the distal segment support frame, and the external end points of the two curved rods, each away from the connection point, are respectively connected to the proximal segment support frame.

10. The bracket according to claim 9, characterized in that: The orthographic projections of more than one pocket-shaped support rod on the axial cross section of the stent are located between the orthographic projections of the two curved rods in the leaflet fixing assembly on the axial cross section of the stent.

11. The bracket according to claim 10, characterized in that: The number of the pocket-shaped support rods and the leaflet fixing components is 2 respectively; the two leaflet fixing components are arranged opposite to each other in the circumferential direction of the stent; the orthographic projection of the first pocket-shaped support rod on the axial section of the stent is located in the middle of the orthographic projections of the two curved rods in the first leaflet fixing component on the axial section of the stent, and the orthographic projection of the second pocket-shaped support rod on the axial section of the stent is located in the middle of the orthographic projections of the two curved rods in the second leaflet fixing component on the axial section of the stent.

12. The bracket according to claim 9, characterized in that: The curved rod has more than two arc-shaped parts; A reference plane is determined based on the connection points of two curved rods in the leaflet fixing assembly and the external end points of the two curved rods, and the two or more arc-shaped portions of the curved rods of the leaflet fixing assembly are distributed on different sides of the reference plane.

13. The bracket according to claim 12, characterized in that: Among the two or more arc-shaped portions of the curved rod, the arc-shaped portion close to the distal segment support frame is located on the proximal side of the corresponding reference plane.

14. The bracket according to claim 13, characterized in that: The curved rod has two arc-shaped portions, the arc-shaped portion close to the distal segment support frame is located on the proximal side of the corresponding reference plane, and the arc-shaped portion away from the distal segment support frame is located on the distal side of the reference plane.

15. The bracket according to claim 9, characterized in that: The proximal segment support frame includes more than two proximal segment support grids; The external end points of the two curved rods in the leaflet fixing assembly are respectively connected to different proximal segment support grids.

16. The bracket according to claim 15, characterized in that The number of the proximal segment support grid and the number of the leaflet fixing components are respectively 2; the two leaflet fixing components are arranged opposite to each other in the circumferential direction of the stent; The external end point of a curved rod in the first leaflet fixing assembly and the external end point of a curved rod in the second leaflet fixing assembly are both connected to the first positioning ear, and the first positioning ear is connected to the first proximal segment support grid; the external end point of another curved rod in the first leaflet fixing assembly and the external end point of another curved rod in the second leaflet fixing assembly are both connected to the second positioning ear, and the second positioning ear is connected to the second proximal segment support grid.

17. The bracket according to claim 16, characterized in that: The first positioning ear and the second positioning ear are respectively provided with two positioning holes distributed along the axial direction of the stent, and the positioning holes are used to fix the leaflets.

18. The bracket according to claim 15, characterized in that The proximal segment support grid has a V-shaped frame, and the V-shaped frame includes more than one triangular sub-grid and / or more than one quadrilateral sub-grid.

19. The bracket according to claim 18, characterized in that The V-shaped opening of the V-shaped frame is less than or equal to a set threshold, and the V-shaped opening is positively correlated with the included angle of two sides forming the V-shaped structure.

20. The bracket according to claim 15, characterized in that The distal segment support frame includes a first distal segment support grid and a second distal segment support grid; The first distal segment support grid is arranged below a curved rod in the first leaflet fixing assembly and a curved rod in the second leaflet fixing assembly; The second distal segment support grid is arranged below another curved rod in the first leaflet fixing assembly and another curved rod in the second leaflet fixing assembly; A hindering film is fixed on the first distal segment support grid and the second distal segment support grid respectively, and the material of the hindering film includes a polymer material and / or a biogenic material.

21. The bracket according to claim 20, characterized in that The first distal segment support grid has a first W-shaped frame, and the second distal segment support grid has a second W-shaped frame; The connection points of the two curved rods in the first leaflet fixing assembly are respectively connected to one end of the first W-shaped frame and one end of the second W-shaped frame through a first positioning rod; the connection points of the two curved rods in the second leaflet fixing assembly are respectively connected to the other end of the first W-shaped frame and the other end of the second W-shaped frame through a second positioning rod; The W-shaped frame includes more than one triangular sub-grid and / or more than one quadrilateral sub-grid.

22. The bracket according to claim 1, characterized in that The proximal section support frame is an inverted table body, and the distal section support frame is an upright table body. The maximum radial dimension of the upper base of the inverted table body is greater than the maximum radial dimension of the lower base, and the maximum radial dimension of the upper base of the upright table body is smaller than the maximum radial dimension of the lower base.

23. The bracket according to claim 22, characterized in that The minimum upper base angle of the inverted platform is smaller than the minimum lower base angle of the upright platform.

24. The bracket according to claim 22 or 23, characterized in that: The angle of the minimum upper base angle of the inverted platform body is within the numerical range of 75° to 85°, and the angle of the minimum lower base angle of the upright platform body is within the numerical range of 80° to 87°.

25. The bracket according to claim 1 or 2, characterized in that: The number of the leaflet fixing assembly is 1, and the stent also includes a fixing attachment; The fixing attachment is connected between the proximal segment support frame and the distal segment support frame, and is arranged opposite to the leaflet fixing assembly in the circumferential direction of the support.

26. The bracket according to claim 25, characterized in that The leaflet fixing assembly comprises two curved rods connected in a V-shaped structure; the connection points of the two curved rods are connected to the distal segment support frame, and the external end points of the two curved rods, each away from the connection point, are respectively connected to the proximal segment support frame; The fixing attachment has the same structure as the leaflet fixing component.

27. The bracket according to claim 26, characterized in that The orthographic projection of the pocket-shaped support rod on the axial cross section of the stent is located between the orthographic projections of the two curved rods in the leaflet fixing assembly on the axial cross section of the stent.

28. The bracket according to claim 1, characterized in that The radial dimension of the rods constituting the leaflet fixing assembly is greater than the radial dimension of the rods constituting the remaining parts of the stent, so that when the stent is expanded in the blood vessel, the contact surface per unit length of the rods constituting the leaflet fixing assembly with the blood vessel is greater than the contact surface per unit length of the rods constituting the remaining parts with the blood vessel; The remaining parts include one or more of the following parts: the proximal segment support frame, the pocket-shaped support rod, and the distal segment support frame.

29. The bracket according to claim 28, characterized in that The radial dimension of the rods constituting the leaflet fixing assembly is n times the radial dimension of the rods constituting the remaining parts, wherein 1<n≤2.

30. The bracket according to claim 28, characterized in that The radial dimension of the rod constituting the leaflet fixing assembly is 0.1 mm to 0.5 mm.

31. An artificial venous valve, characterized in that: A stent comprising a leaflet and any one of claims 1 to 30; The leaflet is fixedly arranged on the leaflet fixing component.

32. The artificial venous valve according to claim 31, characterized in that: The leaflet has a fixed edge, which is fixed on two curved rods connected in a V-shaped structure in the leaflet fixing component; the leaflet also has a free edge, which is located between the two ends of the fixed edge of the leaflet.

33. The artificial venous valve according to claim 32, characterized in that: The leaflet also has a first leaflet ear, a second leaflet ear and a positioning portion; The first leaflet ear and the second leaflet ear of the leaflet are respectively fixed at the first positioning ear and the second positioning ear, and the positioning portion of the leaflet is fixed at the positioning rod connected to the connection point of two curved rods in the corresponding leaflet fixing component.

34. The artificial venous valve according to claim 32, characterized in that: The free edge of the leaflet is an arc-shaped edge convex toward its fixed edge.

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