Valve stent

Abstract

The invention discloses a valve stent which comprises an outer-layer stent and a tubular stent body with a near-end opening and a far-end opening, and the tubular stent body comprises a uniform grid area and a special-shaped grid area which are arranged in the circumferential direction; the uniform grid area comprises a plurality of basic grid units which are sequentially arranged in the circumferential direction, and each basic grid unit at least comprises a first middle grid; the special-shaped grid area at least comprises a supporting grid unit and an avoiding grid unit, and the area of the avoiding grid unit is larger than that of at least two first middle grids; the plurality of basic grid units and the supporting grid units and the avoiding grid units of the special-shaped grid area form a radial supporting part of the outer-layer stent; the inner-layer stent is arranged in the outer-layer stent, and a preset radial gap is kept between the inner-layer stent and the far-end part of the outer-layer stent; the near end of the inner-layer stent and the near end of the outer-layer stent are connected so as to be relatively fixed; and the valve leaflet is fixedly connected to the side wall of the inner-layer stent. According to the method and the device, the grid special dissimilation is performed on the local part, so that the bionic avoidance of a specific area is achieved.

Description

Technical Field

[0001] The present invention relates to the field of medical devices, and particularly to a valve stent for reducing conduction block. Background Art

[0002] Cardiac valve disease is one of the common cardiovascular diseases, mainly including valve lesions such as aortic valve, mitral valve, and tricuspid valve. At present, surgical valve replacement and repair are the main treatment methods, but they have disadvantages such as large trauma, high risk, and high complication incidence. In recent years, transcatheter valve replacement technology has gradually emerged, with advantages such as minimally invasive and no need for extracorporeal circulation, becoming a new direction for the treatment of valve diseases.

[0003] Existing transcatheter implanted artificial valves mostly adopt self-expanding valve stents with a coherent and uniform grid structure. After the self-expanding valve stent is fully expanded, the radial support force generated by it will uniformly press on the entire annulus region, which may directly compress the atrioventricular node region, and then cause atrioventricular block, affecting the normal conduction function of the heart.

[0004] Aiming at the problem of conduction block that may be caused by valve implantation, the prior art discloses a pressure-dividing stent configuration, that is, the valve stent adopts a double-layer stent design: the outer soft stent is fixed to the valve leaf through barbs, and the inner functional stent maintains hemodynamics. At the same time, the "champagne cork-like" conformation (narrow neck and wide body) is used to balance radial support and flexibility, the ventricular segment has higher hardness to resist displacement, and the atrial segment is set to be flexible to reduce the compression on the atrioventricular node. However, although the pressure-dividing stent design can avoid conduction block, it may sacrifice radial stability and increase the risk of paravalvular leakage.

[0005] Therefore, it is necessary to provide an artificial valve that can better fit the human annulus and avoid conduction block at the same time. Summary of the Invention

[0006] To achieve the above object, on the one hand, the present invention provides a valve stent, including: An outer stent, having a tubular stent body with proximal and distal openings, the tubular stent body including a uniformly meshed area and a shaped meshed area arranged circumferentially; the uniformly meshed area includes a plurality of basic mesh units arranged sequentially along the circumference, and each basic mesh unit includes at least a first medium mesh; the shaped meshed area includes at least a support mesh unit and an avoidance mesh unit, and the area of the avoidance mesh unit is larger than the area of at least two first medium meshes; the plurality of basic mesh units and the support mesh unit and the avoidance mesh unit of the shaped meshed area together constitute the radial support portion of the outer stent; the radial support portion of the outer stent provides substantially the same radial support performance as a valve stent composed only of basic mesh units; The inner stent is placed inside the outer stent and maintains a predetermined radial gap from the distal portion of the outer stent; the proximal end of the inner stent is connected to the proximal end of the outer stent to achieve relative fixation between the two. The valve leaflets are fixedly connected to the side wall of the inner stent.

[0007] In one embodiment, the basic grid unit includes two circumferentially adjacent first medium grids and one first small grid; the first small grid is located on the distal side of the two first medium grids and in the middle position between them. The special-shaped grid area includes one large grid, one second medium grid, and two second small grids; the large grid and the second medium grid are arranged adjacent to each other circumferentially, and the two second small grids are located on the distal side of the large grid and the second medium grid and are spaced apart; the second medium grid constitutes the support grid unit, and the large grid constitutes the avoidance grid unit. Multiple first medium grids, one second medium grid, and one large grid constitute the radial support portion of the valve stent. The radial support force missing in the blank area of the avoidance grid unit is provided by the edge of the avoidance grid unit.

[0008] In one embodiment, the first medium grid and the second medium grid have the same shape.

[0009] In one embodiment, the area of the avoidance grid unit is n times the area of the first medium grid, where 2 ≤ n ≤ 4.

[0010] In one embodiment, connection claws are arranged on the distal sides of the first small grid and the second small grid; the outer stent and the inner stent are fixedly connected through the connection claws. The radial support portion of the outer stent transmits the received radial force to the inner stent through the first small grid, the second small grid, and the connection claws.

[0011] In one embodiment, the outer contour of the avoidance grid unit is heart-shaped.

[0012] In one embodiment, the avoidance grid unit includes a left bottom rod, a right bottom rod, a left support rod, a right support rod, and multiple connecting rods; the left support rod, the left bottom rod, the right bottom rod, the right support rod, and the multiple connecting rods are connected end to end in sequence to form a heart-shaped contour; the multiple connecting rods provide the upper circumferential radial support of the avoidance grid unit, and the left bottom rod and the right bottom rod provide the lower circumferential radial support of the avoidance grid unit.

[0013] In one embodiment, the first medium grid is a closed hexagonal grid formed by a V-shaped rod, an inverted V-shaped rod, and two parallel rods. Multiple connecting rods are arranged in a zigzag manner, forming multiple sharp corners facing the distal side and multiple hanging corners facing the proximal side.

[0014] In one embodiment, auxiliary fixing holes are provided at each of the hanging corners.

[0015] In one embodiment, the included angle of the V-shaped rod is 60° - 90°, and the included angle of the inverted V-shaped rod is 60° - 90°; the angle of the sharp corner is 60° - 90°; The included angle between the left bottom rod and the right bottom rod is 120° - 160°; The included angle between the left support rod and the left bottom rod is 110° - 140°.

[0016] According to another aspect of the present application, there is provided a valve stent, comprising: A uniform grid area and a special-shaped grid area, which are arranged circumferentially together to form a tubular stent body with proximal and distal openings; The uniform grid area includes a plurality of basic grid units arranged in sequence along the circumference, and each of the basic grid units includes at least a first medium grid; The special-shaped grid area includes at least a support grid unit and an avoidance grid unit, and the area of the avoidance grid unit is larger than the area of at least two first medium grids; the plurality of basic grid units, the support grid unit and the avoidance grid unit of the special-shaped grid area together form the radial support part of the valve stent; The radial support part of the valve stent provides substantially the same radial support performance as the valve stent composed only of basic grid units.

[0017] Compared with the prior art, the valve stent described in the present application has the following beneficial effects:

[0018] 1. Local grid specialization is carried out at the positions where the valve stent body is prone to conduction block, and a large-area avoidance area is constructed to form bionic avoidance, reducing the compression on the atrioventricular node area and effectively reducing the risk of conduction block.

[0019] 2. The special-shaped grid area adopts an asymmetric design, arranging avoidance grid units and support grid units. For the structure of a single-layer valve stent, the radial supporting force of the special-shaped grid area is provided jointly by the avoidance grid unit and the support grid unit. The central area of the avoidance grid unit is left empty, and its edge increases the structural strength and rigidity. The "stress redistribution" is used to disperse the force originally concentrated in the avoidance area to the surrounding areas to make up for the missing radial supporting force in the empty area. The support grid unit further compensates for the radial supporting force of the avoidance area to ensure that the overall radial supporting performance of the special-shaped grid area is almost equivalent to that of the traditional uniform stent composed only of basic grid units.

[0020] 3. When the valve stent adopts a double-layer stent structure of an outer stent and an inner stent, the radial supporting force of the valve stent is jointly provided by the radial supporting part of the outer stent and the inner stent. The outer stent in the double-layer stent structure has better adaptability to the native valve annulus.

[0021] 4. While taking into account the streamline of the overall structure of the valve stent, the valve stent can be retracted back into the delivery system again during the release process to cope with possible accidents during the operation and reduce the surgical risk.

[0022] 5. The outer stent in a single-layer valve stent or a double-layer valve stent adopts an egg-shaped contour design. Through bionic morphological matching, it fits the anatomical characteristics of the human valve annulus more closely, greatly reducing the risk of paravalvular leakage and improving the sealing performance of the valve. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a schematic structural diagram of a valve stent shown according to an embodiment of the present application; Figure 2 is Figure 1 a top view of the shown valve stent; Figure 3 is an unfolded view of a partial main body structure design of a valve stent shown according to an embodiment of the present application; Figure 4 is an unfolded view of a partial structure of a valve stent composed only of a first middle grid shown according to an embodiment of the present application; Figure 5 is an unfolded view of a partial structure of a valve stent shown according to an embodiment of the present application; Figure 6 is an unfolded view of a partial structure of another valve stent shown according to an embodiment of the present application; Figure 7 is an unfolded view of a partial structure of yet another valve stent shown according to an embodiment of the present application; Figure 8 is a schematic structural diagram of a valve stent constituting a control group shown according to an embodiment of the present application; Figure 9 is a schematic diagram of the position after the intersection point of two connecting rods in an avoidance grid unit is recovered as shown according to an embodiment of the present application; Figure 10 is a schematic structural diagram of a valve stent shown according to an embodiment of the present application; Figure 11 is a schematic diagram of the comparison of the radial supporting forces between the valve stent and the traditional uniform valve stent shown according to an embodiment of the present application. REFERENCE SIGNS

[0024] 10 - Outer stent; 20 - Inner stent; 100 - Uniform grid area; 110 - Basic grid unit; 111 - First medium grid; 112 - First small grid; 200 - Irregular grid area; 210 - Support grid unit; 220 - Avoidance grid unit; 221 - Large grid; 222 - Second medium grid; 223 - Second small grid; 224 - Connecting claw; 510 - Left bottom rod; 520 - Right bottom rod; 530 - Left support rod; 540 - Right support rod; 550 - Link rod; 560 - Suspended corner; 570 - Auxiliary fixing hole. Specific embodiments

[0025] To make the above - mentioned objects, features, and advantages of the present invention more obvious and understandable, the following describes the specific embodiments of the present invention in detail with reference to the accompanying drawings. Many specific details are set forth in the following description in order to fully understand the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0026] It should be clear that the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative work belong to the scope of protection of the present application.

[0027] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms "a", "the", and "said" used in the embodiments of the present application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.

[0028] The orientation or positional relationship indicated by terms such as "bottom", "proximal end", "lower part", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention.

[0029] Unless otherwise clearly defined and limited, the terms "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0030] As used in this specification, the singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise. The terms "first", "second", "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. The term "or" is generally used in the sense of including "and / or" unless the context clearly dictates otherwise.

[0031] As used herein, the term "axial" refers to the axis of the stent body. The proximal end refers to the side closer to the center of the heart (such as the atrium or ventricle) or the upstream side of the blood flow, and can also be referred to as the inflow end. The distal end refers to the side away from the center of the heart or the downstream side of the blood flow, and can also be referred to as the outflow end.

[0032] Traditional single-layer valve stents or pressure-divided double-layer valve stents both use uniform meshes to achieve radial support. However, the uniform meshes will exert continuous high pressure on the atrioventricular node region, and it is impossible to avoid compressing the atrioventricular node. The valve stent of the present invention adopts a partition design of a uniform mesh area and a special-shaped mesh area. While maintaining the overall radial support force, it realizes local area optimization and avoids rigid compression. The specific working principle is as follows:

[0033] In one embodiment, the valve stent includes an outer stent, an inner stent, and valve leaflets. Figure 1 FIG. is a schematic structural diagram of a valve stent shown according to an embodiment of the present application. Figure 2 is Figure 1 a top view of the shown valve stent. Refer to Figure 1 and Figure 2 As shown, the outer stent 10 in the valve stent has a tubular stent body with proximal and distal openings. The tubular stent body includes a circumferentially arranged uniform mesh area 100 and a special-shaped mesh area 200. The inner stent 20 is disposed inside the outer stent 10 and maintains a predetermined radial gap with the distal portion of the outer stent. The proximal end of the inner stent 20 is connected to the proximal end of the outer stent 10 to achieve relative fixation of the two. The valve leaflets (not shown in the figure) are fixedly connected to the side wall of the inner stent 20.

[0034] Figure 3 FIG. is a developed view of a partial main body structure design of an outer stent shown according to an embodiment of the present application. Refer to Figure 3 As shown, the uniform mesh area 100 in the outer stent includes a plurality of basic mesh units 110 arranged in sequence along the circumference. Each basic mesh unit 110 includes at least a first intermediate mesh 111. It should be noted that for the convenience of display, Figure 1Only a part of the uniform grid area is shown. The irregular grid area 200 at least includes a support grid unit 210 and an avoidance grid unit 220, and the area of the avoidance grid unit 220 is larger than the area of at least two first medium grids 111. The plurality of basic grid units 110 and the support grid unit 210 and the avoidance grid unit 220 of the irregular grid area 200 together constitute the radial support part of the outer stent. The radial support part of the outer stent provides substantially the same radial support performance as the outer stent composed only of basic grid units. For the valve stent composed of basic grid units, reference can be made to Figure 4 The partial structure unfolded view of the valve stent composed only of the first medium grid shown in

[0035] In the above technical solution, the uniform grid area 100 formed by arranging a plurality of basic grid units 110 continuously in the circumferential direction provides a basic radial support force to ensure that the valve frame can stably fit the main area of the valve annulus when unfolded. The avoidance grid unit in the irregular grid area 200 designs a large-area avoidance area (area ≥ 2 first medium grids) at the position corresponding to the atrioventricular node area. By reducing the local grid, the grid density of the area is reduced, and the radial pressure on the atrioventricular node area is reduced or eliminated. At the same time, the avoidance grid unit transfers the radial support force to the edge rods ( Figure 3 The thick black rods surrounding the avoidance grid unit in Figure 4 ) to ensure that the overall radial support performance is almost equivalent to that of the traditional uniform stent composed only of basic grid units (see

[0036] In some embodiments, see Figure 5 , the basic grid unit includes two circumferentially adjacent first medium grids 111 and a first small grid 112. The first small grid 112 is located on the distal side of the two first medium grids 111 and in the middle position between them.

[0037] In the traditional design of the basic grid unit, the radial support force is mainly provided by the first medium grids arranged uniformly in the circumferential direction. In the above embodiment, each basic grid unit includes two circumferentially adjacent first medium grids 111 and a first small grid 112. The first small grid 112 is located on the distal side (i.e., the side away from the cardiac apex) of the two first medium grids 111 and in the middle position between them. In this structure, the two first medium grids 111 are used to bear the force of the native valve annulus, the first small grid 112 provides the connection with the inner stent, and when the outer stent is subjected to a radial force, it transfers the received force to the inner stent to maintain the structural stability of the outer stent.

[0038] The irregular grid region 200 includes a large grid 221, a second medium grid 222, and two second small grids 223. The large grid 221 and the second medium grid 222 are arranged adjacent to each other circumferentially. The two second small grids 223 are located on the distal side of the large grid 221 and the second medium grid 222 and are spaced apart. The second medium grid 222 forms the support grid unit 210, and the large grid 221 forms the avoidance grid unit 220. Multiple first medium grids 111, a second medium grid 222, and a large grid 221 form the radial support portion of the valve stent. The radial support force missing in the blank area in the avoidance grid unit 220 is provided by the edge members of the avoidance grid unit 220.

[0039] In the design of the irregular grid region 200, the radial support force is jointly provided by a second medium grid 222 and a large grid 221. The large grid 221 forms the avoidance grid unit 220, and the central area of the large grid 221 is left blank, but its edge (the border of the large grid 221) is designed to have a certain structural strength and rigidity. See Figure 3 and / or Figure 5 , the rod width of the border of the large grid 221 is greater than the rod widths of the first medium grid 111 and the second medium grid 222. The border of the large grid 221 is similar to "stress redistribution", which disperses the force originally concentrated in the atrioventricular node area to the surrounding areas to make up for the missing support force in its blank area. The avoidance grid unit 220 in this application does not completely lose its support function, but provides support force through the edge. The second medium grid 222, as the support grid unit 210, can concentrate the support force in non-critical areas, that is, provide radial support force in areas that do not require avoidance. The second small grids 223 are located on the distal side and are spaced apart. The second small grids 223 have the same working principle as the first small grids 112, that is, the second small grids 223 also provide connection to the inner stent, and when the outer stent is subjected to a radial force, transfer the force received to the inner stent to maintain the structural stability of the outer stent. In Figure 5 In the structure of the outer stent shown, the support grid unit 210 and the avoidance grid unit 220 form a complete stent structure through a second small grid 223 to maintain the integrity of the structure of the irregular grid region 200, and when the outer stent is subjected to a radial force, it can better withstand the force and transfer the force to the inner stent to maintain the structural stability of the outer stent.

[0040] In the above embodiments, the irregular grid region 200 forms a stable mechanical network through cross-connection between grids. Even if the avoidance grid unit 220 has a local blank area, through the combination of the above support grid unit 210 and avoidance grid unit 220, the irregular grid region 200 can achieve a balance between radial support force and avoidance requirements, not only meeting the mechanical requirements, but also being able to better adapt to the tissue morphology and achieve avoidance of key areas.

[0041] In one embodiment, the area of the avoidance grid unit 220 is n times the area of the first middle grid 111, where 2 ≤ n ≤ 4. As a more preferred embodiment, when the first middle grid 111 and the second middle grid 222 have the same shape, the area of the avoidance grid unit 220 is 3 times the area of the first middle grid 111, that is, the area of the avoidance grid unit 220 is equivalent to the area of 3 first middle grids 111. Since the larger the area of the avoidance grid unit 220, the larger the blank area, the greater the radial support force dispersed to the surrounding frame. If we want to achieve the balance of the radial force support, the stress that the side bars of the avoidance grid unit 220 need to bear will be greater. Correspondingly, the bar width of the avoidance grid unit 220 will be wider. In the above embodiments, the larger the value of n, the wider the bar width of the avoidance grid unit 220.

[0042] When n = 2 or 4, that is, the area of the avoidance grid unit 220 is 2 or 4 times the area of the first middle grid 111, refer to Figure 6 and Figure 7 the partial structural schematic diagram of the outer stent in the corresponding embodiment shown, from Figure 6 and Figure 7 it can be seen that the avoidance grid unit 220 further includes a second middle grid 222. The purpose of setting the second middle grid 222 is to ensure that the avoidance grid unit 220 can form an even number of connection regions extending to the distal side, so as to just couple with the structure of the second small grid 223.

[0043] In some embodiments, the first middle grid 111 and the second middle grid 222 have the same shape. The first middle grid 111 and the second middle grid 222 adopt the same shape design. In the radial support part, the missing support force in the avoidance area of the large grid 221 is jointly compensated by the mechanical transmission and elastic deformation of the second middle grid 222 on one side and the first middle grid 111 on the other side. Since the grid structures on both sides of the avoidance area have the same shape, it can ensure the uniformity of the local radial support force in the avoidance area.

[0044] In some embodiments, refer to Figures 5 - 7 , connection claws 224 are arranged on the distal sides of both the first small grid 112 and the second small grid 223. The connection claws 224 can be used as the pulling points for transcatheter intervention, for operations such as pulling and aligning the valve stent. When the valve stent in the present application is used to manufacture the outer stent of the pressure-dividing stent, the connection claws are used to connect with the inner stent and are used to achieve the pulling of the pressure-dividing stent during the process of delivering the valve stent.

[0045] The valve stent described in this application can be contracted and expanded in the radial direction. When the valve stent is delivered transcatheter, it is in a contracted state. After the valve stent reaches the predetermined position, it expands and is supported at the native annulus by the radial support part of the outer stent. The special-shaped grid area 200 corresponds to the area to be avoided. The avoidance grid unit 220 uses "stress redistribution" to disperse the force originally concentrated in the avoidance area to the surrounding areas to make up for the lack of radial support force in its blank area. At the same time, the radial support force received by the outer stent is transmitted to the inner stent by the first small grid 112, the second small grid 223 and the connecting claws of the outer stent. Since the stiffness of the inner stent is greater than that of the outer stent, when it receives the radial acting force transmitted by the outer stent, it can absorb the radial acting force transmitted by the outer stent and maintain its original contour state, thus making the valve stent have better stability and preventing the outer stent from falling off.

[0046] In an embodiment, the outer contour of the avoidance grid unit 220 is heart-shaped. Refer to Figure 5 , in an implementation of the heart-shaped outer contour, the avoidance grid unit 220 includes a left bottom rod 510, a right bottom rod 520, a left support rod 530, a right support rod 540 and a plurality of connecting rods 550. The left support rod 530, the left bottom rod 510, the right bottom rod 520, the right support rod 540 and the plurality of connecting rods 550 are connected end to end in sequence to form a heart-shaped contour; the plurality of connecting rods 550 provide the upper circumferential radial support force of the avoidance grid unit 220, and the left bottom rod 510 and the right bottom rod 520 provide the lower circumferential radial support force of the avoidance grid unit 220.

[0047] The outer stent described in this application can be contracted and expanded in the radial direction. When the outer stent is in the expanded state, the position of the intersection point of the left bottom rod 510 and the right bottom rod 520 closest to the proximal end is basically the same as the position of the node of the first middle grid 111 closest to the proximal end. When the outer stent is in the contracted state, the position of the intersection point of the left bottom rod 510 and the right bottom rod 520 closest to the proximal end is lower than the position of the node of the first middle grid 111 closest to the proximal end.

[0048] In the above-mentioned scheme of the heart-shaped outer contour, the left bottom rod 510 and the right bottom rod 520 are used to ensure that the deformation state of the large grid 221 is uniform during the implantation process, to ensure that the valve stent does not twist, and to form a radial support for the lower periphery of the avoidance grid unit 220. The left support rod 530 and the right support rod 540 serve as the boundary support points of the large grid 221, maintain the overall grid shape and support, and do not participate in the deformation. Multiple connecting rods 550 are staggered and connected to provide the large grid 221 with the same order of magnitude of upper periphery radial support as the remaining grids. The area formed by the staggered multiple connecting rods 550 and the left bottom rod 510 and the right bottom rod 520 together provide the overall support stiffness of the avoidance grid unit 220. Relying on the same stiffness support, the overall radial support force of the valve stent is basically consistent with the radial support force of the valve stent of the uniform grid composed of only the first middle grid 111.

[0049] Artificial valve products may have various abnormalities during use. The valve stent shown in this application can be recycled to stop the operation if it is not fully released. The valve stent in this application, the basic grid units of the uniform grid area 100 have the same structure and are evenly arranged adjacent to each other, which can ensure the streamlined structure of the valve stent during the recycling process. The supporting grid unit 210 of the special-shaped grid area 200 has the same structure as the first middle grid 111, so it can be smoothly stored. The left bottom rod 510 and the right bottom rod 520 in the avoidance grid unit 220 are set at an obtuse angle, which can also achieve the smooth recovery of the valve stent during the secondary recovery process of the valve stent. The specific reasons are as follows:

[0050] In one embodiment of a valve stent, see Figure 8 In order to set up a blank area, the bottom structure of the avoidance grid unit 220 can adopt the same structural form as the multiple connecting rods 550, that is, the multiple connecting rods 550 are staggered. The bottom structure adopts the staggered arrangement of multiple connecting rods 550. Due to the symmetry of the upper and lower structures, the manufacturing process of the avoidance grid unit 220 will be relatively simple. However, when the avoidance grid unit 220 of this structure is recycled for the second time, due to the mutual squeezing between the connecting rods 550, the junction between the two connecting rods 550, that is, the sharp corner facing the distal end of the valve stent (see Figure 8 Due to the concentration of stress, the valve stent will move away from the axis of the stent, forming a lateral bending angle. Figure 9 (Left figure), the vertical line in the figure is the theoretical position of the intersection of the two connecting rods 550 after recovery, the curved line is the actual position of the intersection of the two connecting rods 550 after recovery, and the angle α between the curved line and the straight line is the side bending angle, which will form a recovery obstacle between the conveying device. Due to the existence of the side bending angle, the valve stent cannot be normally recovered for the second time.

[0051] In the technical solution shown in the present application, the bottom structure of the avoidance grid unit 220 adopts a left bottom rod 510 and a right bottom rod 520 arranged at an obtuse angle, and there are multiple connecting rods 550 above the area spanned by the left bottom rod 510 and the right bottom rod 520. During the recovery process of the valve stent, the left bottom rod 510 and the right bottom rod 520 approach each other with their intersection point as the fulcrum, and the circumferential space after the recovery of the multiple connecting rods 550 needs to be reserved between the two. Therefore, the stress concentration generated by the close extrusion during the contraction process of the left bottom rod 510 and the right bottom rod 520 will be at the connection of the left bottom rod 510 and the right bottom rod 520, with the angle downward. This angle conforms to the recovery direction of the delivery device, and even if a side bending angle is generated, it will not affect the recovery function. Therefore, uniform recovery of the valve stent can be achieved. See Figure 9 (right figure). It can be seen from this that while taking into account the streamline of the overall structure of the valve stent, after the valve stent is released, it can be retracted back into the delivery system again to cope with possible accidents during the operation, greatly reducing the operation risk.

[0052] In one embodiment, see Figure 10 , the first middle grid 111 is a closed hexagonal grid composed of a V-shaped rod, an inverted V-shaped rod, and two parallel rods; the second middle grid 222 has the same structure as the first middle grid 111. The multiple connecting rods 550 are arranged in a zigzag manner, forming multiple sharp corners facing the distal side and multiple hanging corners 560 facing the proximal side.

[0053] See Figure 10 the embodiment shown. An auxiliary fixing hole 570 is provided at each hanging corner 560. During the manufacturing process of the valve stent, the valve stent needs to be expanded. During the expansion process, the valve stent body is fixed to the expansion mold through the auxiliary fixing hole 570, thereby realizing the fixation of the valve stent body and ensuring the accuracy of the expansion of the valve body.

[0054] It can be seen Figure 10 , both the first middle grid 111 and the second middle grid 222 adopt hexagonal grids, and the main body of the valve stent forms a honeycomb-constrained grid topology structure. The traditional circular outer stent can be understood as a valve stent with a circular projection shape composed of the first middle grid 111. In the present application, the avoidance grid unit 220 of the special-shaped grid area 200 replaces three V-shaped rods with a deep V-shaped frame structure, so that the stress transmission path bypasses the atrioventricular node sensitive area and avoids compressing the atrioventricular node.

[0055] In one embodiment, the included angle of the V-shaped rod is 60° - 90°, and the included angle of the inverted V-shaped rod is 60° - 90°; the angle of the sharp corner is 60° - 90°. The included angle between the left bottom rod 510 and the right bottom rod 520 is 120° - 160°; the included angle between the left support rod 530 and the left bottom rod 510 is 110° - 140°. The left support rod 530 is connected to the left bottom rod 510 by a curved connection at the included angle, and the bending radius is 0.5 - 3 mm. The valve stent formed by these structural parameters can conform to the recovery direction of the delivery device and achieve uniform recovery of the valve stent.

[0056] The following uses simulation data to verify and compare the radial support forces provided by the valve stent with the described structure in this application and a traditional uniform valve stent (selecting a valve stent composed only of the circumferential arrangement of the first middle meshes 111) under the same load (this load is set according to the bionic data of the native annulus of the human body). See Figure 11 .

[0057] It can be seen from Figure 11 that in the initial stage, both the valve stent with the described structure in this application and the traditional uniform valve stent show disorders in radial support force (the adaptation period of the valve stent to the native annulus at the beginning of support). However, as time goes by, the radial support force of the valve stent provided in this application (line 2) is almost the same as that of the traditional uniform valve stent (line 1).

[0058] In the above embodiments of different valve stents, the outer stent can adopt a valve stent design with an elliptical or egg-shaped projection profile. See Figure 2 . Through bionic morphological matching, the excessive local pressure caused by shape differences is reduced, and the direct compression on the atrioventricular junction area is reduced. In the preferred solution, the ratio of the major axis to the minor axis of the elliptical or egg-shaped outer stent is 1.2:1. The valve stent with this ratio can better adapt to the shape of the native annulus, thereby reducing the negative impact on the native annulus caused by radial support and reducing the direct compression on the avoidance area. When the valve stent is adapted to the native annulus of the tricuspid valve, the valve stent with this ratio interacts with the annulus, providing both the required radial support force and reducing the compression on the atrioventricular node, avoiding the occurrence of conduction block.

[0059] It can be seen from the above technical solutions that the valve stent in this application performs local grid specialization at the position where conduction block is likely to occur, achieving the effect of bionic avoidance, reducing the compression on the atrioventricular node area, and thus reducing the risk of conduction block.

[0060] According to another aspect of the present application, there is also provided a valve stent, including: A uniform grid area 100 and a special-shaped grid area 200, which are circumferentially arranged together to form a tubular stent body with proximal and distal openings; The uniform grid area 100 includes a plurality of basic grid units arranged in sequence along the circumferential direction, and each basic grid unit includes at least a first medium grid 111; The special-shaped grid area 200 includes at least a support grid unit 210 and an avoidance grid unit 220, and the area of the avoidance grid unit 220 is larger than the area of at least two first medium grids 111; the plurality of basic grid units and the support grid unit 210 and the avoidance grid unit 220 of the special-shaped grid area 200 together constitute the radial support part of the valve stent; The radial support part of the valve stent provides substantially the same radial support performance as the valve stent composed only of basic grid units.

[0061] The valve stent disclosed in this part has the same various structural designs and working principles as the structure of the outer stent shown above Figures 1 - 10 and will not be elaborated here.

[0062] The valve stent in this embodiment is a single-layer stent structure, which can be used as the outer stent of a pressure-dividing valve stent (a double-layer stent structure including an outer stent and an inner stent), or can be used alone as a valve stent. For example, as an aortic valve stent, when used alone, its stiffness is greater than that of the outer stent used in the pressure-dividing valve stent to provide sufficient radial support.

[0063] Obviously, according to the content of this specification, many modifications and changes can be made. This specification selects and specifically describes these embodiments to better explain the principle and practical application of the present invention, so that those skilled in the art can make good use of the present invention. The present invention is only limited by the claims and their full scope and equivalents.

Claims

1. A valve stent, characterized in that, Comprising: An outer stent, having a tubular stent body with proximal and distal openings, the tubular stent body including a uniformly meshed area and a specially shaped meshed area arranged circumferentially; the uniformly meshed area includes a plurality of basic mesh units arranged sequentially in the circumferential direction, each of the basic mesh units including at least a first medium mesh; the specially shaped meshed area includes at least a support mesh unit and an avoidance mesh unit, the area of the avoidance mesh unit being larger than the area of at least two first medium meshes; the plurality of basic mesh units, together with the support mesh unit and the avoidance mesh unit of the specially shaped meshed area, constitute the radial support portion of the outer stent; the radial support portion of the outer stent provides substantially the same radial support performance as a valve stent composed only of basic mesh units; An inner stent, placed inside the outer stent and maintaining a predetermined radial gap with the distal portion of the outer stent; the proximal end of the inner stent is connected to the proximal end of the outer stent to achieve relative fixation between the two; Valve leaflets, fixedly connected to the side wall of the inner stent.

2. The valve stent according to claim 1, wherein The basic mesh unit includes two circumferentially adjacent first medium meshes and one first small mesh; the first small mesh is located on the distal side of the two first medium meshes and in the middle position between them; The specially shaped meshed area includes one large mesh, one second medium mesh and two second small meshes; the large mesh and the second medium mesh are arranged adjacent to each other in the circumferential direction, and the two second small meshes are located on the distal side of the large mesh and the second medium mesh and are spaced apart; the second medium mesh constitutes the support mesh unit, and the large mesh constitutes the avoidance mesh unit; A plurality of first medium meshes, one second medium mesh and one large mesh constitute the radial support portion of the valve stent; The radial support force missing from the blank area in the avoidance mesh unit is provided by the edge of the avoidance mesh unit.

3. The valve stent according to claim 2, wherein, Connection claws are arranged on the distal sides of the first small mesh and the second small mesh; The outer stent and the inner stent are fixedly connected through the connection claws; the radial support portion of the outer stent transmits the received radial force to the inner stent through the first small mesh, the second small mesh and the connection claws.

4. The valve stent according to claim 2, wherein The first medium mesh and the second medium mesh have the same shape.

5. The valve stent according to claim 4, wherein The area of the avoidance mesh unit is n times the area of the first medium mesh, where 2 ≤ n ≤ 4.

6. The valve stent according to any one of claims 1 to 5, characterized in that, The outer contour of the avoidance mesh unit is heart-shaped.

7. The valve stent according to claim 6, wherein, The avoidance mesh unit includes a left bottom rod, a right bottom rod, a left support rod, a right support rod and a plurality of connecting rods; the left support rod, the left bottom rod, the right bottom rod, the right support rod and the plurality of connecting rods are connected end to end in sequence to form a heart-shaped contour; the plurality of connecting rods provide the upper circumferential radial support of the avoidance mesh unit, and the left bottom rod and the right bottom rod provide the lower circumferential radial support of the avoidance mesh unit.

8. The valve stent according to claim 7, characterized in that, The first medium mesh is a closed hexagonal mesh composed of a V-shaped rod, an inverted V-shaped rod and two parallel rods; The plurality of connecting rods are arranged in a zigzag manner, forming a plurality of sharp corners facing the distal side and a plurality of suspended corners facing the proximal side.

9. The valve stent according to claim 8, wherein The included angle of the V-shaped rod is 60° - 90°, and the included angle of the inverted V-shaped rod is 60° - 90°; the angle of the sharp corner is 60° - 90°; The included angle between the left bottom rod and the right bottom rod is 120° - 160°; The included angle between the left support rod and the left bottom rod is 110° - 140°.

10. A valve stent, characterized in that, Comprising: A uniform grid area and a special-shaped grid area, which are arranged circumferentially to jointly form a tubular stent body with proximal and distal openings; The uniform grid area includes a plurality of basic grid units arranged in sequence along the circumferential direction, and each of the basic grid units includes at least a first medium grid; The special-shaped grid area includes at least a support grid unit and an avoidance grid unit, and the area of the avoidance grid unit is larger than the area of at least two first medium grids; the plurality of basic grid units, the support grid unit and the avoidance grid unit of the special-shaped grid area jointly form the radial support part of the valve stent; The radial support part of the valve stent provides substantially the same radial support performance as the valve stent composed only of basic grid units.

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