An artificial venous valve and its stent

Abstract

The present disclosure provides an artificial venous valve and a stent thereof, and relates to the technical field of medical devices. The stent comprises a proximal segment support frame, a leaflet fixing assembly, a bag-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 for fixing a leaflet; a first end of the bag-shaped support rod is connected with the proximal segment support frame, and a second end thereof is connected with the distal segment support frame; the bag-shaped support rod comprises one or more than one S-shaped part connected in sequence, different half-arc portions in the one or more than one S-shaped part have different opening degrees, and the opening degree of the half-arc portion of the S-shaped part close to the distal segment support frame is greater than that of the half-arc portion of the S-shaped part close to the proximal segment support frame.

Description

Technical Field

[0001] This specification relates to the field of medical device technology, and in particular to an artificial venous valve and its stent. Background Technology

[0002] Veins are responsible for carrying blood from all parts of the body back to the heart. To prevent backflow, veins contain valves. When blood flows towards the heart, the valves open, allowing blood to flow in; after the blood has flowed out, the valves close. Venous valves are "one-way valves" that ensure the return of blood from veins to the heart. Damage or disease of venous valves can cause venous blood to reflux, leading to venous hypertension and subsequently chronic venous disease (CVD).

[0003] Some scientists have proposed creating artificial venous valves to replace diseased venous valves. Artificial venous valves can be implanted into target locations within veins (such as damaged or diseased native venous valves), thereby replacing the native valves and preventing blood reflux.

[0004] Some embodiments in this specification are intended to provide an artificial venous valve and its stent that are structurally more stable and better adapted to the intravascular environment of veins. Summary of the Invention

[0005] This specification provides one or more embodiments of a stent for use in an artificial venous valve, including a proximal support frame, a leaflet fixation assembly, a pocket-shaped support rod, and a distal support frame; the leaflet fixation assembly is connected between the proximal and distal support frames and is used to fix the leaflets; a first end of the pocket-shaped support rod is connected to the proximal support frame, and a second end is connected to the distal support frame; when the stent is opened, the pocket-shaped support rod can protrude radially away from the central axis of the stent to form a pocket-shaped space on the proximal side of the leaflet fixation assembly.

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

[0007] According to some embodiments of the bracket described in this specification, the number of pocket-shaped support rods is two or more; the proximal end support frame includes two or more V-shaped support legs respectively connected to the two or more pocket-shaped support rods; when the bracket is opened, the V-shaped opening of the V-shaped support leg is greater than a set threshold, and the V-shaped opening is positively correlated with the included 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 leg.

[0008] According to some embodiments of the bracket described in this specification, when the bracket is opened, the height of the point on the pocket-shaped support rod that is furthest from the central axis of the bracket along the radial direction of the bracket is related to the V-shaped opening and / or length of the V-shaped support foot.

[0009] According to some embodiments of the bracket described in this specification, when the bracket is opened, the length of the V-shaped support leg is less than the total length of the one or more S-shaped portions connected in sequence in the pocket-shaped support rod.

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

[0011] According to some embodiments of the bracket described in this specification, in one or more S-shaped portions connected sequentially in the pocket-shaped support rod, the opening of the semi-circle near the distal segment support frame is greater than the opening of the semi-circle near the proximal segment support frame.

[0012] According to some embodiments of the stent described in this specification, the leaflet fixation assembly includes two curved rods connected in a V-shape; the connection point of the two curved rods is connected to the distal segment support frame, and the outer endpoints of the two curved rods, respectively away from the connection point, are connected to the proximal segment support frame.

[0013] According to some embodiments of the bracket described in this specification, the orthographic projection of one or more of the pocket-shaped support rods onto the bracket's axial section lies between the orthographic projections of the two curved rods in the leaflet fixing assembly onto the bracket's axial section.

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

[0015] According to some embodiments of the bracket described in this specification, the curved rod has two or more arcuate portions; a reference plane is determined based on the connection point of the two curved rods in the leaflet fixing assembly and the outer endpoints of the two curved rods, and the two or more arcuate portions of the curved rods of the leaflet fixing assembly are distributed on different sides of the reference plane.

[0016] According to some embodiments of the bracket described in this specification, among the two or more arcuate portions of the curved rod, the arcuate portion closer to the distal segment support frame is located on the proximal side of the corresponding reference plane.

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

[0018] According to some embodiments of the stent described in this specification, the proximal support frame includes two or more proximal support grids; the outer ends of the two cranks in the leaflet fixing assembly are respectively connected to different proximal support grids.

[0019] According to some embodiments of the stent described in this specification, the number of the proximal support grid and the number of the leaflet fixing components are both 2; the two leaflet fixing components are arranged opposite to each other in the circumferential direction of the stent; the outer end point of one of the curved rods in the first leaflet fixing component and the outer end point of one of the curved rods in the second leaflet fixing component are both connected to the first positioning ear, and the first positioning ear is connected to the first proximal support grid; the outer end point of the other curved rod in the first leaflet fixing component and the outer end point of the other curved rod in the second leaflet fixing component are both connected to the second positioning ear, and the second positioning ear is connected to the second proximal support grid.

[0020] According to some embodiments of the bracket described in 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 bracket, and the positioning holes are used to fix the leaflets.

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

[0022] According to some embodiments of the bracket described in this specification, 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 between the two sides forming the V-shaped structure.

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

[0024] According to some embodiments of this 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 one of the curved rods in the first leaflet fixing assembly and one of the curved rods in the second leaflet fixing assembly; the second distal segment support grid is arranged below the other curved rod in the first leaflet fixing assembly and the other curved rod in the second leaflet fixing assembly; a barrier membrane is fixed on the first distal segment support grid and the second distal segment support grid respectively, and the material of the barrier membrane includes polymer materials and / or bio-derived materials.

[0025] According to some embodiments of the support described in this 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 point of the two curved rods in the first leaflet fixing assembly is connected to one end of the first W-shaped frame and one end of the second W-shaped frame respectively through a first positioning rod; the connection point of the two curved rods in the second leaflet fixing assembly is connected to the other end of the first W-shaped frame and the other end of the second W-shaped frame respectively through a second positioning rod; the W-shaped frame includes one or more triangular sub-grids and / or one or more quadrilateral sub-grids.

[0026] According to some embodiments of the bracket described in this specification, the proximal support frame is an inverted truncated pyramid, and the distal support frame is a normal truncated pyramid. The maximum radial dimension of the upper base of the inverted truncated pyramid is greater than the maximum radial dimension of the lower base, and the maximum radial dimension of the upper base of the normal truncated pyramid is less than the maximum radial dimension of the lower base.

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

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

[0029] According to some embodiments of this specification, the number of leaflet fixing components is 1, and the support also includes a fixing accessory; the fixing accessory is connected between the proximal support frame and the distal support frame, and is disposed opposite to the leaflet fixing components in the circumferential direction of the support.

[0030] According to some embodiments of the stent described in this specification, the leaflet fixation assembly includes two curved rods connected in a V-shape; the connection point of the two curved rods is connected to the distal segment support frame, and the outer endpoints of the two curved rods, respectively away from the connection point, are connected to the proximal segment support frame; the fixing accessory has the same structure as the leaflet fixation assembly.

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

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

[0033] According to some embodiments of the bracket described in this specification, the radial dimension of the rod constituting the leaflet fixing assembly is n times the radial dimension of the rod constituting the remaining parts, where 1 < n ≤ 2.

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

[0035] One or more embodiments of this specification also provide an artificial venous valve, including leaflets and a stent as described above; the leaflets are fixedly disposed on the leaflet fixing assembly.

[0036] According to some embodiments of the artificial venous valve described in this specification, the leaflet has a fixed side, which is fixed to two curved rods connected in a V-shape in the leaflet fixing assembly; the leaflet also has a free side, which is located between the two ends of the fixed side of the leaflet.

[0037] According to some embodiments of the artificial venous valve described in this specification, the leaflet further has a first leaflet auricle, a second leaflet auricle, and a positioning part; the first leaflet auricle and the second leaflet auricle of the leaflet are respectively fixed at the first positioning auricle and the second positioning auricle, and the positioning part of the leaflet is fixed at the positioning rod connected to the connection point of the two curved rods in the corresponding leaflet fixing assembly.

[0038] According to some embodiments of the artificial venous valve described in this specification, the free edge of the valve leaflet is an arcuate edge convex toward its fixed edge. Attached Figure Description

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

[0040] Figure 1This is a perspective view of an artificial venous valve as shown in some embodiments of this specification.

[0041] Figure 2 It is a cut mesh surface of the bracket shown in some embodiments of this specification.

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

[0043] Figure 4 This is a second side view of the bracket shown according to some embodiments of this specification.

[0044] Figure 5 This is a schematic diagram of the structure of the S-shaped part according to some embodiments of this specification.

[0045] Figure 6 This is a structural schematic diagram of the V-shaped support foot and the pocket-shaped support rod according to some embodiments of this specification.

[0046] Figure 7 yes Figure 6 Side view.

[0047] Figure 8 This is a schematic diagram of the structure of the leaflet fixing assembly according to some embodiments of this specification.

[0048] Figure 9 This is a schematic diagram of the structure of the curved rod in the leaflet fixing assembly shown in some embodiments of this specification.

[0049] Figure 10 This is a first side view of the proximal support frame shown according to some embodiments of this specification.

[0050] Figure 11 This is a second side view of the proximal support frame shown according to some embodiments of this specification.

[0051] Figure 12 This is a first side view of the distal segment support frame shown according to some embodiments of this specification.

[0052] Figure 13 This is a second side view of the distal segment support frame shown according to some embodiments of this specification.

[0053] Figure 14 This is a second side view of the bracket shown according to some other embodiments of this specification.

[0054] Figure 15 This is a side view of the bracket shown in some embodiments of this specification.

[0055] Figure 16It is a cut mesh surface of the bracket shown in other embodiments of this specification.

[0056] Figure 17 This is a schematic diagram of the leaflets according to some embodiments of this specification.

[0057] Figure 18 This is a first-state diagram of an artificial venous valve in a venous vessel, as shown in some embodiments of this specification.

[0058] Figure 19 This is a second-state diagram of an artificial venous valve in a venous vessel, as shown in some embodiments of this specification.

[0059] Figures 20-22 These are diagrams illustrating different states of the leaflets according to some embodiments of this specification.

[0060] Figure 23 This is a schematic diagram of the structure of an artificial venous valve according to other embodiments of this specification.

[0061] Figure 24 yes Figure 23 The diagram shows the state of an artificial venous valve in a venous vessel.

[0062] The diagram shows the following markings: 1. Proximal support frame; 11. V-shaped support foot; 12. Proximal 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 connection points; 25. Connection point; 3. Pocket-shaped support rod; 31. S-shaped part; 32. Straight rod; 33. Farthest point; 4. Distal support frame; 41. Distal 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 contact area; 6. Positioning ear; 61. Positioning hole; 7. Positioning rod; 8. Barrier membrane. Detailed Implementation

[0063] To more clearly illustrate the technical solutions of the embodiments in this specification, the embodiments will be described in detail below with reference to the accompanying drawings. Obviously, the content described below are some examples or embodiments of this specification. For those skilled in the art, without creative effort, the technical solutions or means disclosed in this specification can be applied to other scenarios based on this technical content.

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

[0065] Artificial venous valves (hereinafter referred to as artificial valves) generally consist of a stent and leaflets, with the leaflets fixed to the stent. The stent needs to provide good support to ensure that the leaflets are effectively fixed in the blood vessel. Its materials can include metals, polymers, and biomaterials, with metals including tantalum, medical-grade stainless steel, and nickel-titanium alloys. The stent can have a folded-up state and an expanded state. Before implantation into a vein, the stent is in the folded-up state to compress into the sheath of the catheter. The artificial venous valve is then inserted into the vein through the catheter. When it reaches the target implantation location, the stent expands, and thereafter the artificial venous valve supports the blood vessel at the target implantation location and functions in place of the native venous valve. In some embodiments, when the stent expands, the proximal side of the leaflet (i.e., the side of the leaflet facing the heart after implantation into the vein) can form a pocket-shaped space (or, in other words, the stent bulges radially away from the center of the blood vessel). This allows blood flow to bypass the pocket-shaped space, preventing venous blood from stagnating and forming thrombi in the angled area between the leaflet and the vessel wall. To facilitate proper expansion of the stent within the blood vessel, the stent material needs to possess a certain degree of elasticity or flexibility. Therefore, how to enable the stent to simultaneously possess good support and flexibility is a problem worthy of research.

[0066] Therefore, some embodiments of this specification propose a support that, through structural improvements, effectively meets both the requirements for support and deformation.

[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 supported state and the retracted state.

[0068] Figure 1 This is a perspective view of an artificial venous valve according to some embodiments of this specification, showing the structural morphology of the artificial venous valve when the stent is expanded. For example... Figure 1As shown in the figures, some embodiments of this specification provide an artificial venous valve stent and leaflet 5, wherein the stent further includes a proximal support frame 1, a leaflet fixation assembly 2, a pocket-shaped support rod 3, and a distal support frame 4. The proximal segment refers to the section of the stent closest to the heart after the artificial valve is implanted into a vein, while the distal segment is the section furthest from the heart. The leaflet fixation assembly 2 connects the proximal support frame 1 and the distal support frame 4 to fix the leaflet. The pocket-shaped support rod 3 is arranged along the axial direction of the stent, with its first end connected to the proximal support frame 1 and its second end connected to the distal support frame 4. To facilitate differentiation of the different components of the stent from the figures, Figure 1 The connection between the proximal support frame 1 and the leaflet fixing assembly 2 and the pocket-shaped support rod 3 is illustrated using dashed lines, while the connection between the distal support frame 1 and the leaflet fixing assembly 2 and the pocket-shaped support rod 3 is illustrated using double-dotted lines. Figure 1 The artificial venous valve shown has a double-leaf symmetrical leaflet design. When the artificial venous valve is inserted into the blood vessel, the stent is wrapped around the blood vessel wall in the circumference. The two leaflets 5 form a one-way valve in the axial direction of the blood vessel, which opens and closes periodically with the blood flow.

[0069] In some embodiments, the support can be formed by laser cutting of tubing made of a suitable material. As an example, a structural "pattern" of the support can be designed on a computer device, and then cut into the tubing using laser printing technology to obtain a support in a folded state. Figure 2 The cut mesh surface of the bracket shown in some embodiments of this specification allows for longitudinal slicing and flattening of the cut tubing to obtain the desired result. Figure 2 The state shown. (And) Figure 1 akin, Figure 2 The connection between the proximal support frame 1 and the leaflet fixation assembly 2 and the pocket-shaped support rod 3 is illustrated using dashed lines, while the connection between the distal support frame 1 and the leaflet fixation assembly 2 and the pocket-shaped support rod 3 is illustrated using double-dotted lines. Figure 2 The cut mesh shown is arranged in a column shape with the vertical axis as the central axis, which can obtain the aforementioned folded support.

[0070] contrast Figure 1 and Figure 2As can be seen, when the stent is deployed, the pocket-shaped support rod 3 protrudes radially away from the central axis of the stent, forming a pocket-shaped space on the proximal side of the leaflet fixing assembly 2 (or leaflet 5). After the artificial venous valve is implanted into the blood vessel, on the one hand, blood flow can form a bypass in the pocket-shaped space, preventing venous blood from stagnating and forming thrombi in the angle area between the leaflet and the blood vessel wall; however, on the other hand, the stent will be subjected to axial force 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 bulge radially towards the central axis of the stent (such as folding inward), ultimately leading to the failure of the artificial valve.

[0071] Figure 3 This is a first side view of the bracket shown according to some embodiments of this 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, to a certain extent, increase the instability stress threshold 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 may be 0.3~0.5mm, and the lateral width of the formed S-shaped portion 31 (e.g., Figure 6 The width D shown can reach 1~2mm, indicating that the S-shaped part 31 can effectively increase the lateral dimension of the pocket-shaped support rod 3. The S-shaped part 31 can also increase the contact area between the stent and the blood vessel, preventing the artificial valve from shifting under blood pressure.

[0072] In some embodiments, the opening of at least one half-arc of at least one S-shaped portion is greater than 0. For example... Figure 5 As shown, a semi-arc can be the upper or lower half of an S-shape. A semi-arc can be considered as a shape composed of two straight lines and the arc between them. The opening of a semi-arc is positively correlated with the angle between the tangents at its two endpoints. For example, the opening of a semi-arc can be related to... Figure 5 The magnitude of the θ angle is related to this. A semi-circular opening greater than 0 means that its two straight lines are not parallel. The larger the semi-circular opening, the greater the rigidity of the S-shaped section, and the smaller the probability of instability of the pocket-shaped support rod 3. Therefore, the local rigidity of the pocket-shaped support rod can be adjusted by changing the semi-circular opening of the S-shaped section. In some embodiments, the semi-circular opening can be taken from the numerical range [15°, 20°]. In some embodiments, all semi-circles in one or more sequentially connected S-shaped sections 31 have equal openings, such as... Figure 5 As shown on the left. In other embodiments, different semicircles in one or more S-shaped portions 31 connected in sequence can have different openings, such as... Figure 5As shown on the right, the opening of the upper semi-circle in one or more S-shaped sections 31 can be characterized by angle θ1, and the opening of the lower semi-circle can be characterized by angle θ2, where angle θ1 is smaller than angle θ2. Specifically, the opening of the semi-circle near the distal support frame 4 in the stent is greater than the opening of the semi-circle near the proximal support frame 1. Thus, when the stent is opened, the part of the pocket-shaped support rod 3 near the distal support frame 4 has greater strength. Even if the part near the proximal support frame 1 experiences a certain degree of instability and inward folding, the stent can still form a larger pocket-shaped space in the area near the proximal side of the leaflet 5, ensuring that blood can form turbulence, 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-circles, 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-circles, such as 3, 5, etc.

[0074] Figure 10 This is a first side view of the proximal support frame according to some embodiments of this specification. (In conjunction with...) Figure 3 as well as Figure 10 In some embodiments, the proximal support frame 1 includes V-shaped support feet 11 connected to the pocket-shaped support rods 3. Specifically, the V-shaped support feet 11 can correspond one-to-one with the pocket-shaped support rods 3. Figure 2 In the cut mesh surface, the V-shaped support legs 11 converge to form two approximately parallel sides. When the support frame is extended, the V-shaped support legs 11 extend in a V-shape. By adjusting the dimensions of each part in the proximal support frame 1, the V-shaped opening of the V-shaped support legs 11 when the support frame is extended can be adjusted. The V-shaped opening is positively correlated with the included 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 dimension, and the greater its rigidity or mechanical strength. Therefore, when the bracket is extended, the V-shaped support leg 11 can further increase the rigidity of the pocket-shaped support rod 3, preventing inward bending. 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°, specifically 35°, 40°, 45°, 50°, 55°, etc.

[0076] Figure 4 This is a second side view of the bracket shown according to some embodiments of this specification. Figure 6 This is a structural schematic diagram of the V-shaped support foot and the pocket-shaped support rod according to some embodiments of this specification. (Combined with...) Figure 4 and Figure 6 As shown, when the stent expands, the V-shaped support leg 11 and the pocket-shaped support rod 3 protrude away from the central axis of the stent, making the side profile of the support appear as a drum-shaped structure. The V-shaped support leg 11 can provide good drum-shaped support force, preventing 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 leg 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 leg 11. The larger the V-shaped opening, the lower the height of the connection point in the axial direction, 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, allowing the stent to expand the blood vessel more effectively while reducing the support force, thereby reducing damage to the blood vessel. As mentioned earlier, the structural design of the S-shaped part can also increase the support stiffness and prevent inward bending. In some embodiments, the distance between the upper endpoints of the two sides of the V-shaped support leg and the connection point of the two sides can be used as the length of the V-shaped support leg, such as... Figure 6 The length h1 is shown. 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 part 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 sections 31 connected sequentially in the pocket-shaped support rod 3 are connected to the distal segment support frame 4 via straight rods 32, that is, the connection between the S-shaped section and the second end of the pocket-shaped support rod 3 is a straight rod 32. The S-shaped section can transition better structurally via the straight rod to connect with the distal segment support frame. In some embodiments, the total length h2 of the one or more sequentially connected S-shaped sections 31 is greater than the length h3 of the straight rod 32. Experiments have shown that this arrangement of the length relationship between the V-shaped support foot, the S-shaped section, and the straight rod allows the pocket-shaped support rod to be easily opened, while also providing good support rigidity after opening.

[0077] Figure 7 for Figure 6 The side view. When the bracket is extended, the pocket-shaped support rod resembles an arch, with the arch having a distance from the central axis of the bracket (such as...). Figure 7 The point furthest from the (shown by the dashed line) can be denoted as (let's call this point) Figure 7The furthest point 33 is located at a distance r1 from the central axis of the support. As mentioned earlier, the height of the connection point between the V-shaped support leg 11 and the pocket-shaped support rod 3 in the axial direction of the support is related to the V-shaped opening of the V-shaped support leg 11. The larger the V-shaped opening, the lower the height of the connection point in the axial direction. Therefore, it can be understood that the V-shaped opening of the V-shaped support leg 11 is related to the height of the furthest point 33 in the axial direction of the support. At the same time, the V-shaped opening of the V-shaped support leg 11 also affects the length of the V-shaped support leg 11. Therefore, in some embodiments, the height of the furthest point 33 in the axial direction of the support is also related to the length of the V-shaped support leg 11. Thus, when designing the cut mesh surface of the support, by adjusting the lengths of the two sides of the V-shaped support leg 11, the V-shaped opening and / or length of the V-shaped support leg 11 when the support is opened can be adjusted, thereby adjusting the height of the furthest point 33 in the axial direction of the support.

[0078] In some embodiments, when the stent is deployed, the height of the farthest point 33 along the stent axial direction is equal to the height of the connection point between the leaflet fixation assembly 2 and the proximal support frame 1 along the stent axial direction. In other embodiments, when the stent is deployed, the farthest point 33 is closer to the distal support frame 4 along the stent axial direction relative to the connection point between the leaflet fixation assembly 2 and the proximal support frame 1. The offset of the point on the pocket-shaped support rod farthest from the central axis of the stent along the stent axial direction relative to the distal support frame further ensures the formation of a larger pocket-shaped space in the region near the proximal side of the leaflet 5, allowing blood to turbulently flow.

[0079] Figure 8 This is a schematic diagram of the leaflet fixing assembly according to some embodiments of this specification. (In conjunction with...) Figure 1 , Figure 3 as well as Figure 8 In some embodiments, the leaflet fixation assembly 2 may include two curved rods 21 and 22 connected in a V-shape. The connection point 25 of the two curved rods is connected to the distal segment support frame 4. The outer end point 23 of the curved rod 21, away from the aforementioned connection point, is connected to the proximal segment support frame 1. The outer end point 24 of the curved rod 22, away from the aforementioned connection point, is also connected to the proximal segment support frame 1. The curved rod in the leaflet fixation assembly 2 is the junction of the leaflet and the support frame. For example, the leaflet can be sewn onto the curved rod with sutures. The two curved rods are symmetrically designed, presenting a V-shaped structure in space. When the artificial valve expands in the vein, the curved rod in the leaflet fixation assembly can conform to the blood vessel, and together with the leaflet, it can provide an axial seal, preventing blood leakage at the fixed edge of the leaflet.

[0080] In some embodiments, the crank may have two or more arcuate portions, specifically, it may have two, three, or more arcuate portions. In some embodiments, a reference plane may be defined, in which the connection point 25, the external endpoint 23, and the external endpoint 24 of the leaflet fixing assembly are located; that is, the reference plane can be defined by these three points. Different arcuate portions in the crank may be distributed on different sides of the reference plane. Figure 9 This is a schematic diagram of the curved rod in the leaflet fixing assembly shown in some embodiments of this specification. (In conjunction with...) Figure 1 , Figure 4 as well as Figure 9 Taking the curved rod 21 as an example, the curved rod 21 has an arc-shaped portion 211 and an arc-shaped portion 212. Figure 9 The dashed lines in the figure represent the projection lines of the reference plane. The arc-shaped part 211 is located on the lower side of the reference plane, and the arc-shaped part 212 is located on the upper side of the reference plane.

[0081] Combination Figure 1 or Figure 4 It is easy 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 arcuate sections of the curved rod, the arcuate section closer to the distal segment of the support frame (such as arcuate section 242) is located on the upper side of the reference plane, i.e., the proximal side. This design allows for a certain creep allowance in the support structure for the leaflets, extending the service life of the artificial valve. More information on the effects of creep can be found in the subsequent description of the leaflets. As an example, Figure 9 The arc-shaped 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-shaped portion 211, which is farther 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 leaflet fixation assemblies 2 is two, and they are arranged opposite each other in the circumferential direction of the stent. The leaflets on the two leaflet fixation assemblies can form a one-way valve structure in the axial direction of the blood vessel. In some embodiments, the pocket-shaped support rods can correspond one-to-one with the leaflet fixation assemblies, see [reference]. Figure 3 The orthographic projection of the pocket-shaped support rod onto the axial section of the stent lies between the orthographic projections of the two curved rods in the corresponding leaflet fixation assembly onto the axial section of the stent. Thus, when the stent is deployed, a pocket-shaped space can be formed above the proximal side of each leaflet fixation assembly. In other embodiments, the number of pocket-shaped support rods can be greater; for example, one leaflet fixation assembly can correspond to more than two pocket-shaped support rods. More pocket-shaped support rods can, to some extent, better support the pocket-shaped space of the leaflet fixation assembly. See also... Figure 1 and Figure 4For either of the two sets of pocket-shaped support rods and leaflet fixing components, the orthographic projection of the pocket-shaped support rod on the axial section of the support is located between the orthographic projections of the two curved rods in the leaflet fixing component on the axial section of the support. The pocket-shaped space supported by the pocket-shaped support rod for the leaflet fixing component is more symmetrical and uniform.

[0083] In addition to the V-shaped support feet for connecting the pocket-shaped support rod, the proximal support frame also includes a proximal support grid for connecting the leaflet fixing assembly. Figure 11 This is a second side view of the proximal support frame according to some embodiments of this specification. The proximal support grid 12 may have a V-shaped frame 121, in which a plurality of support rods 122 are fixedly connected to form one or more quadrilateral subgrids within the V-shaped frame 121. In other embodiments, a greater number of support rods 122 may be arranged in the V-shaped frame 121 to form a plurality of triangular subgrids. It is readily understood that in yet another embodiment, the arrangement of the support rods 122 can be flexibly configured to form at least one quadrilateral subgrid and at least one triangular subgrid within the V-shaped frame 121. The presence of subgrids can increase the support stiffness of the V-shaped frame 121, allowing the proximal support grid 12 to support blood vessels on the one hand, and withstand the pressure of blood flow on the valve leaflets when the leaflets are closed on the other. In some embodiments, the density of the subgrids is positively correlated with the support stiffness, and the number of subgrids in the V-shaped frame 121 can be adjusted according to factors such as the weight of the valve fixation assembly.

[0084] In some embodiments, the V-shaped opening of the V-frame 121 can be less than or equal to a set threshold, which can 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 can have the same set threshold, that is, in some embodiments, the V-shaped opening of the V-frame 121 can be no greater than the V-shaped opening of the V-shaped support leg 11. As mentioned above, the support stiffness of the V-shaped structure can be positively correlated with the V-shaped opening. In order to cooperate with the pocket-shaped support rod to form a larger pocket space, the V-shaped support leg 11 needs to have a larger support stiffness and deformation space. Therefore, its V-shaped opening can be appropriately increased to improve the support stiffness. At the same time, the simple frame structure of the V-shaped support leg 11 allows it to have a larger deformation space. Due to the limitations of the overall structure or size of the bracket, the V-shaped frame 121 can have a smaller V-shaped opening, while its support stiffness can be improved by several sub-grids in the V-shaped frame 121. Of course, in the actual implementation process, sub-grids can also be set in the V-shaped support feet according to the actual situation, and the size, shape and density of the sub-grids can also be changed.

[0085] The proximal support grid can be connected to the outer end of the curved rod. Specifically, the same proximal support grid can be connected to the outer end of the curved rod in different leaflet fixing assemblies. In other words, the outer end of two curved rods in the same leaflet fixing assembly are connected to different proximal support grids respectively. In this way, the V-shaped support feet and the proximal support grid can be alternately distributed along the axial direction of the support in the proximal support frame, 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, there are two leaflet fixation components, positioned opposite each other in the circumferential direction of the stent. Correspondingly, there are also two proximal support grids. The outer endpoints of one curved rod in the first leaflet fixation component and one curved rod in the second leaflet fixation component are both connected to the first proximal support grid. The outer endpoints of the other curved rod in the first leaflet fixation component and the other curved rod in the second leaflet fixation component are both connected to the second proximal support grid.

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

[0088] The distal support grid is used to support the distal blood vessels, and in some embodiments, the distal segment support frame may have a grid structure. Figure 12 and Figure 13 The structure of the distal support frame is shown from the first and second lateral views. The distal support frame may include a distal support grid, which can be arranged below the curved rod of the leaflet fixing assembly to support the leaflet fixing assembly.

[0089] Combination Figure 1 , Figure 4 as well as Figure 13 Taking a double-leaf artificial valve as an example, in some embodiments, a first distal segment support grid is provided below one of the curved rods in the first leaflet fixing assembly and one of the curved rods in the second leaflet fixing assembly, which are connected together by external endpoints; a second distal segment support grid is provided below the other curved rod in the first leaflet fixing assembly and the other curved rod in the second leaflet fixing assembly.

[0090] Figure 12 The first lateral view shows the side views of the first and second distal segment support grids. The two distal segment support grids are distinguished by a dashed line; that is, the side views of different distal segment support grids 41 are shown on either side of the dashed line. See also... Figure 13 In some embodiments, the distal segment support grid 41 has a W-shaped frame 411, which includes a plurality of struts 412 to form one or more triangular subgrids and / or one or more quadrilateral subgrids. Further description of the struts forming subgrids can be found in the foregoing description of the proximal segment support grid, and will not be repeated here.

[0091] Figure 14 This is a second side view of the bracket according to other embodiments of this specification. (See also...) Figure 13 as well as Figure 14 As shown, in some embodiments, a barrier membrane 8 may be fixed on the distal segment support grid 41. In some embodiments, the material of the barrier membrane may include a polymer material or a bio-derived material, wherein the polymer material may further be polysiloxane, polytetrafluoroethylene, polyurethane, or styrene polymer, etc., and the bio-derived material may further be porcine pericardium, porcine heart valve, bovine pericardium, or bovine heart valve, etc. After the artificial valve has been in the blood vessel for a period of time, biological tissues of an organism (such as the human body) may proliferate and gradually cover the artificial valve. Compared with metal scaffolds, biological tissues are more likely to adhere to the leaflets, which have similar material properties. When biological tissues proliferate and cover the leaflets, the thickness of the leaflets increases, thereby affecting the opening and closing sensitivity. The barrier membrane has a material similar to or the same as the leaflets and can "drain" at least part of the proliferating biological tissues, thereby hindering or reducing the proliferation of biological tissues on the leaflets and extending the service life of the artificial valve. Simultaneously, when biological tissues proliferate and coat the barrier membrane, they can increase the adhesion between the stent and the blood vessel, thereby preventing stent displacement within the vessel and increasing the circumferential seal of the artificial valve. The mesh structure of the distal segment support grid is even more conducive to fixing the barrier membrane.

[0092] See 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 via a positioning rod 7. The positioning rod can be used to fix corresponding parts of the leaflet (such as the leaflet positioning portion), and in some embodiments, the positioning rod can be considered part of the leaflet fixing assembly. Figure 1 , Figure 4 as well as Figure 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 respectively 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 respectively 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 rods of the corresponding leaflet fixing assembly to increase stability.

[0093] Figure 15 This is a side view of the bracket shown according to some embodiments of this specification. For example... Figure 15 As shown, in some embodiments, when the stent is extended, its proximal support frame has an inverted truncated pyramid structure, with the cubit-shaped support rod and leaflet fixing assembly bulging radially away from the central axis to form a cubit-shaped or drum-shaped structure, while the distal support frame has a regular truncated pyramid structure. For example... Figure 15 As shown, when the leaflets of the artificial valve close (or simply artificial valve closure), blood can flow around the waist drum-shaped area, preventing blood stasis and thrombosis.

[0094] Generally, a frustum can be defined as the portion between the base and the cross-section obtained by cutting the cone with a plane parallel to its base. The frustum can be considered to have two bases, an upper and a lower one. The cross-section of the frustum or cone can be of any shape, such as a triangle, polygon, circle, ellipse, etc. The maximum radial dimension of the upper base of an inverted frustum is greater than that of the lower base, while the maximum radial dimension of the upper base of a normal frustum is smaller than that of the lower base. Taking a frustum with a circular cross-section as an example, the diameter of the upper base of an inverted frustum is greater than that of the lower base, while the diameter of the upper base of a normal frustum is smaller than that of the lower base. Taking a frustum with an elliptical cross-section as another example, the major axis of the upper base of an inverted frustum is greater than that of the lower base, while the major axis of the upper base of a normal frustum is smaller than that of the lower base. It should be noted that in some embodiments of this 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 expands, the pocket-shaped support rod bulges further away from the stent's central axis relative to the leaflet fixation assembly. Correspondingly, the proximal support frame supporting both can be an inverted truncated pyramid with an elliptical or nearly elliptical cross-section, while the distal support frame can be a regular truncated pyramid with an elliptical or nearly elliptical cross-section. When the stent expands, its proximal support frame has an inverted truncated pyramid structure, meaning the upper end of the proximal support frame is radially or open, allowing it to expand the blood vessel radially to a certain extent while remaining more closely attached to the vessel wall. This design effectively prevents blood pressure from causing the stent to shift axially towards the distal side when the artificial valve closes, thus reliably fixing the stent in the implantation position. Conversely, the distal support frame has a regular truncated pyramid structure, meaning the lower end of the distal support frame is radially or open, allowing it to expand the blood vessel radially to a certain extent while remaining more closely attached to the vessel wall. This design effectively prevents blood impact from causing the stent to shift axially towards the proximal side when the artificial valve opens. Of course, overall, 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 along the axial direction of the blood vessel.

[0096] The base angle can be understood as the angle between a straight line passing through the center of the base surface and the corresponding generatrix on the base surface of the platform. The upper base angle is the angle between a straight line passing through the center of the base surface and the corresponding generatrix on the upper base surface of the platform, and the lower base angle is the angle between a straight line passing through the center of the base surface and the corresponding generatrix on the lower base surface of the platform. In some embodiments, the minimum upper base angle of the inverted truncated pyramid formed by the proximal support frame is smaller than the minimum lower base angle of the upright truncated pyramid formed by the distal support frame. This means that the upper opening size of the proximal support frame can be larger than the lower opening size of the distal support frame in a certain radial direction. When the artificial valve is closed, the pressure exerted by the blood on the artificial valve towards the distal end is greater than the pressure exerted by the blood impact on the artificial valve towards the proximal end when the artificial valve is open. Therefore, a larger upper opening of the stent can better counteract the greater pressure exerted by the blood on the artificial valve towards the distal end. In some embodiments, the angle of the minimum upper base angle of the inverted pyramid corresponding to the proximal support frame is taken from the numerical range of 75° to 85°, and the angle of the minimum lower base angle of the truncated pyramid is taken from the numerical range of 80° to 87°. Taking an elliptical cross-section of the outer contour of the support as an example, the base angle formed by the major axis of the upper base of the inverted truncated pyramid of the proximal support and the generatrix is ​​the minimum upper base angle. Figure 15 In α 1; The angle formed by the major axis of the lower base of the truncated pyramid formed by the distal segment support frame and the generatrix is ​​the minimum lower base angle, such as... Figure 15 In α 2, α 1 < α 2. As an example, α The value of 1 can be 82°. αThe value of 2 can be 85°.

[0097] As mentioned earlier, when the artificial valve expands in the blood vessel, the leaflet fixation assembly can conform to the blood vessel, and the leaflets together can provide an axial seal for the blood vessel, preventing blood leakage around the stent. In some embodiments, to further improve the sealing performance of the leaflet fixation assembly, the rods constituting the leaflet fixation assembly can have a larger radial dimension, thereby increasing the contact area between the leaflet fixation assembly and the blood vessel wall, resulting in a better sealing effect. In some embodiments, the rod can be a basic structural unit constituting the stent, and the radial dimension of the rod can specifically be the radial dimension in one or more directions on the cross-section of the rod, such as the width, thickness, diameter, major axis, minor axis, etc. For the leaflet fixation assembly 2, the rod can include curved rods 21 and 22. In some embodiments, the rods in the leaflet fixation assembly have a larger dimension on their cross-section in the direction parallel to the contact surface between the rod and the blood vessel wall, in order to increase the contact area between the rods in the leaflet fixation assembly and the blood vessel wall.

[0098] Figure 16 This refers to the cut mesh surface of the bracket shown in other embodiments of this specification. Figure 2 akin, Figure 16 The connection points between the proximal support frame 1, the leaflet fixation assembly 2, and the pocket-shaped support rod 3 are illustrated using dashed lines, while the connection points between the distal support frame 1, the leaflet fixation assembly 2, and the pocket-shaped support rod 3 are illustrated using double-dotted lines. In some embodiments, the radial dimension of the rod constituting the leaflet fixation assembly can be 0.1 mm to 0.5 mm. Figure 16 As an example, the width d1 of the rod that makes up the leaflet fixing assembly 1 can be 0.2mm, 0.3mm, 0.4mm, etc.

[0099] In some embodiments, the radial dimension of the rods constituting the leaflet fixing assembly is larger than the radial dimension of the rods constituting the rest of the support. The rest of the support may include one or more of the following: a proximal support frame, a pocket-shaped support rod, and a distal support frame. In some embodiments, for the proximal support frame 1, the rods may include rods constituting the V-shaped support foot 11, rods constituting the V-shaped frame 121, and a plurality of support rods 122. For the pocket-shaped support rod 3, the rods may include bent rods constituting the S-shaped portion 31 and straight rods 32. For the distal support frame 4, the rods may include rods constituting the W-shaped frame 411 and support rods 412.

[0100] See also Figure 16In some embodiments, the width d1 of the rods constituting the leaflet fixation 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 support frame 1. This design ensures that when the stent expands in the blood vessel, the contact area per unit length between the rods constituting the leaflet fixation assembly 1 and the blood vessel is greater than the contact area per unit length between the rods constituting the rest of the stent and the blood vessel. The unit length is introduced for ease of comparison; it can be flexibly set according to the specific length of the stent or stent portion. For example, the unit length can be 1mm, 2mm, 1cm, etc. In some embodiments, the radial dimension of the rods constituting the leaflet fixation 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 membrane is provided around the stent to increase sealing performance, for example, a sealing membrane is wrapped around the distal segment support of the stent. In contrast, some embodiments of this specification achieve improved sealing performance by increasing the radial dimension of the rods that make up the leaflet fixation assembly, which can eliminate the need for a sealing membrane and make the structure of the artificial valve more streamlined.

[0102] For artificial valves, leaflets are also fixed to the leaflet fixation assembly of the stent. The leaflets can be made of bio-derived materials such as porcine pericardium, porcine heart valves, bovine pericardium, and bovine heart valves, or various polymer materials. Figure 17 This is a schematic diagram of the leaflets according to some embodiments of this specification. For example... Figure 17 The leaflet shown is in a flat position, and leaflet 5 has a fixed edge 51. The fixed edge 51 can be used to fix it to the leaflet fixing assembly. Specifically, the fixed edge 51 of leaflet 5 is fixed to two curved rods connected in a V-shape in the leaflet fixing assembly, so the fixed edge 51 can have an arc-shaped edge adapted to the curved rods. Leaflet 5 also has a free edge 52, which is located between the two ends of the fixed edge 51 of leaflet. The free edge 52 is not fixedly connected to the leaflet fixing assembly and is in an open, free state. In an artificial valve, the free edge 52 of leaflet will form an opening for blood flow.

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

[0104] In some embodiments, the corresponding portion of the leaflet can be fixed to the leaflet fixation component by suturing. There are various implementation methods for suturing the leaflets. For example, the leaflet suture can cover the corresponding portion of the leaflet fixation component (such as the crank, positioning lug, or positioning rod) (referred to as a full-coverage suture), or the leaflet suture can only adhere to the inner surface of the corresponding portion of the leaflet fixation component (referred to as a partial-coverage suture). The full-coverage suture allows the blood vessel to contact the flexible leaflet, which is more conducive to sealing. The partial-coverage suture keeps the leaflet away from the blood vessel, preventing the adhesion of biological tissue and avoiding leaflet thickening that could lead to leaflet dysfunction.

[0105] The stent and leaflets constitute a complete artificial valve. In some embodiments, depending on the number of leaflets in the artificial valve, it can be referred to as a single-leaflet valve, a bicuspid valve, or a tricuspid valve. The foregoing embodiments mainly use a bicuspid valve as an example for illustration. In a bicuspid valve, there are two leaflet fixing components, which are arranged opposite each other 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 opening in the artificial valve that allows blood flow. Figure 18 , 19 The diagrams show first and second states of a bicuspid artificial venous valve in a venous vessel, according to some embodiments of this specification. Figure 18 In the middle, the pressure at the proximal end (upper end in the figure) is higher than that at the distal end (lower end in the figure). At this time, the free edges of the two leaflets in the artificial valve come together, and the artificial valve closes. Figure 19 In the middle, the pressure at the distal end (lower end in the diagram) is higher than that at the proximal end (upper end in the diagram). At this point, the free edges of the two leaflets in the artificial valve are separated by the blood flow, and the artificial valve opens. In this way, the artificial valve can replace the native valve in the vein, preventing backflow of blood.

[0106] See also Figure 17In some embodiments, the free edge 52 of the leaflet 5 is an arc-shaped edge convex towards its fixed edge 51. This design effectively prevents the upper edges of the free edges 52 of the two leaflets from bending backwards and separating due to excessive contact area after they are joined together, thus preventing incomplete valve closure. The following is in conjunction with... Figures 20-22 Please provide an explanation.

[0107] like Figure 20 As shown on the left, at this point, the pressure at the distal end of the valve is greater than the pressure at the proximal end, and the valve leaflets are forced open by the blood flow, forming an interleaved opening 56, allowing venous blood to flow back to the heart. When the pressure at the distal end of the valve increases further, the interleaved opening will further enlarge, as... Figure 20 As shown on the right. Figure 21 As shown, the pressure at the proximal end of the valve begins to increase and gradually exceeds the pressure at the distal end, at which point the valve leaflets begin to adhere. Figure 22 As shown, when the pressure near the proximal end of the valve increases further, the contact area between the two leaflets will shift towards 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 area is easily formed when the two leaflets are contacted. This contact area can be located as follows: Figure 21 , 22 The leaflet contact area, encompassed by the dotted line above the free edge of the leaflet, has 57 locations. As the pressure near the heart of the valve further increases, the contact area will further increase, potentially leading to the upper edges of the straight free edges of the two leaflets bending away from each other and separating, resulting in valve insufficiency. Figure 22 The right side view, showing the two leaflets from the side, shows two arc-shaped dashed lines representing the lateral contours of the two leaflets. In this case, blood near the heart is prone to backflow, leading to valve failure. If the free edge 52 of the leaflet is designed as an arc-shaped edge convex to its fixed edge 52, the area of ​​the leaflet contact portion can be effectively reduced, preventing the free edge from bending backwards and improving the reliability of the artificial valve. Experimental data shows that when the blood pressure in the venous vessels is between 3 mmHg and 300 mmHg, the leaflets provided in some embodiments of this specification do not exhibit backward bending in the artificial valve.

[0108] Some embodiments in this specification also provide a single-leaflet artificial valve. (See reference...) Figure 23The single-leaflet artificial valve stent includes a proximal support frame, a leaflet fixation assembly, a fixation accessory, a pocket-shaped support rod, and a distal support frame. The leaflet fixation assembly connects the proximal and distal support frames and is used to fix the leaflet. The fixation accessory connects the proximal and distal support frames and is positioned opposite the leaflet fixation assembly in the circumferential direction of the stent. The pocket-shaped support rod is arranged along the axial direction of the stent; its first end connects to the proximal support frame, and its second end connects to the distal support frame. When the stent is deployed, the pocket-shaped support rod protrudes radially away from the stent's central axis to form a pocket-shaped space on the proximal side of the leaflet fixation assembly.

[0109] contrast Figure 1 as well as Figure 4 It is not difficult to see that the single-leaflet artificial valve stents provided in some embodiments of this specification are simplified versions of the double-leaflet artificial valve stents. Specifically, the single-leaflet artificial valve stent contains only a single leaflet fixing component. To ensure the support effect of the stent, one of the leaflet fixing components in the double-leaflet artificial valve stent can be used as a fixing accessory, with the same structure as the leaflet fixing component, except that no leaflet is fixed thereon. Correspondingly, in the single-leaflet artificial valve stent, the pocket-shaped support rod is only provided at the leaflet fixing component. Specifically, the position of the pocket-shaped support rod is such that its orthographic projection on the stent's axial section lies between the orthographic projections of the two curved rods in the leaflet fixing component on the stent's axial section. For the specific structure or construction of the proximal support frame, leaflet fixing component, fixing accessory, pocket-shaped support rod, and distal support frame in the single-leaflet artificial valve stent, please refer to the description of the foregoing embodiments, which will not be repeated here.

[0110] Figure 24 yes Figure 23 The diagram shows the state of the artificial venous valve in a vein. A single leaflet forms a one-way valve with the opposite vessel wall. When the pressure proximal to the heart is less than the pressure distal to the heart, leaflet 5 separates from the opposite vessel wall, and blood flows back to the heart. When the pressure proximal to the heart is greater than the pressure distal to the heart, the pocket-shaped space proximal to the heart of leaflet 5 fills with blood. Under the pressure of the blood, leaflet 5 expands distally and becomes full. At this point, the free edge of leaflet 5 adheres to the vessel wall, and the artificial valve closes.

[0111] It should be understood that although the embodiments in this specification mainly describe two-leaflet and single-leaflet artificial valves, those skilled in the art can apply the relevant features to three-leaflet or other artificial valves based on the principles and structures described in the embodiments in this specification. Therefore, the modified embodiments obtained by applying the features of the embodiments in this specification are still within the scope of this specification.

[0112] The beneficial effects that the embodiments of this specification may bring 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 opened, and the blood can effectively flow around in the pocket-shaped space to prevent blood stasis and thrombosis; (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 opened in the blood vessel; (3) the platform structure of the proximal support frame and the distal support frame 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 and effectively extend 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, which would lead to separation between leaflets at the free edge and cause valve failure; (6) The sub-grid design in the proximal segment support frame or distal end support frame helps to increase the support force on the leaflet fixing components; (7) The V-shaped support foot design in the proximal segment support frame can be adjusted by adjusting the V-shaped opening of the V-shaped support foot to conveniently adjust the height of the point farthest from the central axis of the stent on the stent axis; (8) The point farthest from the central axis of the stent on the pocket support rod is offset or moved closer to the distal segment support frame along the stent axis, thereby ensuring that a large pocket space is reliably formed in the area near the proximal side of the leaflet, so that blood can form turbulence. It should be noted that different embodiments may produce different beneficial effects. In different embodiments, the beneficial effects may be any one or a combination of the above, or any other possible beneficial effects. The above only lists the beneficial effects of some embodiments of this specification. More beneficial effects of the technical features of the embodiments of this specification can be found in the relevant descriptions of the corresponding embodiments, and will not be listed here.

[0113] The basic concepts have been described above. It is obvious that the detailed disclosure above is merely illustrative and does not constitute a limitation of this specification. Although not explicitly stated herein, various modifications, improvements, and corrections may be made to this specification by those skilled in the art. Such modifications, improvements, and corrections are taught in this specification and therefore remain within the spirit and scope of the exemplary embodiments described herein.

Claims

1. A stent for use in an artificial venous valve, characterized in that, This includes the proximal support frame, leaflet fixation assembly, pocket-shaped support rod, and distal support frame; The leaflet fixing assembly is connected between the proximal support frame and the distal support frame and is used to fix the leaflet; The first end of the pocket-shaped support rod is connected to the proximal support frame, and the second end is connected to the distal support frame. The pocket-shaped support rod includes one or more S-shaped sections connected in sequence. Different semi-circles in the one or more S-shaped sections have different openings. The opening of the semi-circle of the S-shaped section closer to the distal section support frame is greater than the opening of the semi-circle of the S-shaped section closer to the proximal section support frame.

2. The bracket according to claim 1, characterized in that, At least one half-arc of at least one S-shaped section has an opening greater than 0, and the opening of the half-arc is positively correlated with the angle between the tangents at the two endpoints of the half-arc.

3. The stent according to claim 1 or 2, characterized in that, The number of the pocket-shaped support rods is two or more; the proximal support frame includes two or more V-shaped support legs that are respectively connected to the two or more pocket-shaped support rods; when the support is opened, the V-shaped opening of the V-shaped support leg is greater than a set threshold, and the V-shaped opening is positively correlated with the included 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 stent according to claim 3, characterized in that, When the bracket is extended, the length of the V-shaped support leg is less than the total length of one or more S-shaped sections connected in sequence in the pocket-shaped support rod.

5. The bracket according to claim 2, characterized in that, The S-shaped portion near the distal segment of the support frame and the second end of the pocket-shaped support rod are straight rods; The total length of the one or more S-shaped sections connected in sequence in the pocket-shaped support rod is greater than the length of the straight rod.

6. The bracket according to claim 5, characterized in that, The lateral width of the S-shaped section is greater than the lateral width of the straight rod.

7. The stent according to claim 1 or 2, characterized in that, The opening of the semi-circle of the S-shaped section is taken from the numerical range [15°, 20°].

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

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

10. The stent according to claim 1, characterized in that, The leaflet fixing assembly includes two curved rods connected in a V-shape; the connection point of the two curved rods is connected to the distal segment support frame, and the outer endpoints of the two curved rods away from the connection point are respectively connected to the proximal segment support frame.

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

12. The stent according to claim 10, characterized in that, The crank has two or more arc-shaped sections; A reference plane is determined based on the connection point of the two curved rods in the leaflet fixing assembly and the outer endpoints of the two curved rods, with two or more arcuate portions of the curved rods of the leaflet fixing assembly distributed on different sides of the reference plane; Of the two or more arc-shaped portions of the crank, the arc-shaped portion closer to the distal segment support frame is located on the proximal side of the corresponding reference plane.

13. The stent according to claim 12, characterized in that, The crank has two arc-shaped portions. The arc-shaped portion closer to the distal segment support frame is located on the proximal side of the corresponding reference plane, while the arc-shaped portion farther from the distal segment support frame is located on the distal side of the reference plane.

14. The stent according to claim 10, characterized in that, The proximal support frame includes two or more proximal support grids; The outer ends of the two cranks in the leaflet fixing assembly are respectively connected to different proximal support grids.

15. The stent according to claim 14, characterized in that, The number of the proximal support grid and the number of the leaflet fixation components are both 2; the two leaflet fixation components are arranged opposite each other in the circumferential direction of the stent. The outer end of one of the curved rods in the first leaflet fixing assembly and the outer end of one of the curved rods 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 support mesh; the outer end of the other curved rod in the first leaflet fixing assembly and the outer end of the other 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 support mesh. The first positioning ear and the second positioning ear are respectively provided with two positioning holes distributed along the axial direction of the support, and the positioning holes are used to fix the leaflets.

16. The stent according to claim 14, characterized in that, The proximal support grid has a V-shaped frame, and the V-shaped frame includes one or more triangular sub-grids and / or one or more quadrilateral sub-grids. 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 between the two sides forming the V-shaped structure.

17. The stent according to claim 14, 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; Barrier membranes are fixed on the first and second distal segment support grids, respectively, and the barrier membranes are made of polymer materials and / or bio-derived materials. 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 the 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 the second positioning rod. The W-shaped frame includes one or more triangular sub-grids and / or one or more quadrilateral sub-grids.

18. The stent according to claim 1, characterized in that, The proximal support frame is an inverted truncated pyramid, and the distal support frame is a normal truncated pyramid. The maximum radial dimension of the upper base of the inverted truncated pyramid is greater than the maximum radial dimension of the lower base, and the maximum radial dimension of the upper base of the normal truncated pyramid is less than the maximum radial dimension of the lower base. The minimum upper base angle of the inverted platform is smaller than the minimum lower base angle of the upright platform; The minimum upper bottom angle of the inverted platform is taken from the numerical range of 75°~85°, and the minimum lower bottom angle of the upright platform is taken from the numerical range of 80°~87°.

19. The stent according to claim 1 or 2, characterized in that, The number of leaflet fixing components is 1, and the bracket also includes fixing accessories; 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 support frame; The leaflet fixing assembly includes two curved rods connected in a V-shape; the connection point of the two curved rods is connected to the distal segment support frame, and the outer end points of the two curved rods away from the connection point are respectively connected to the proximal segment support frame; The fixing accessory has the same structure as the leaflet fixing assembly; The orthographic projection of the pocket-shaped support rod onto the axial section of the bracket is located between the orthographic projections of the two curved rods in the leaflet fixing assembly onto the axial section of the bracket.

20. The stent according to claim 1, characterized in that, The radial dimension of the rods that make up the leaflet fixation assembly is greater than the radial dimension of the rods that make up the rest of the stent, so that when the stent is spread in the blood vessel, the contact area between the rods that make up the leaflet fixation assembly and the blood vessel per unit length is greater than the contact area between the rods that make up the rest of the stent and the blood vessel per unit length. The remaining parts include one or more of the following parts: the proximal support frame, the pocket-shaped support rod, and the distal support frame; The radial dimension of the rod constituting the leaflet fixing assembly is n times the radial dimension of the rod constituting the remaining parts, where 1 < n ≤ 2, and / or the radial dimension of the rod constituting the leaflet fixing assembly is 0.1 mm to 0.5 mm.

21. An artificial venous valve, characterized in that, Includes leaflets and a stent as described in any one of claims 1 to 20; The leaflet is fixedly mounted on the leaflet fixing assembly; The leaflet has a fixed edge, which is fixed to two curved rods connected in a V-shape in the leaflet fixing assembly; the leaflet also has a free edge, which is located between the two ends of the fixed edge of the leaflet, and the free edge of the leaflet is an arc-shaped edge convex to its fixed edge.

22. The artificial venous valve according to claim 21, characterized in that, The leaflet also has a first leaflet auricle, a second leaflet auricle, and a positioning part; The first leaflet ear and the second leaflet ear of the leaflet are fixed at the first positioning ear and the second positioning ear, respectively. The positioning part of the leaflet is fixed at the positioning rod connected to the connection point of the two curved rods in the corresponding leaflet fixing assembly.

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