A valve stent and a prosthetic valve device comprising the same

Abstract

This disclosure proposes a valve stent composed of multiple rhomboid grids. Each rhomboid grid consists of four wave rods. The valve stent has a compressed state and an expanded state. A first region and a second region are sequentially connected along the axial direction of the valve stent from the outflow end to the inflow end. The first region has a truncated cone structure that tapers towards the outflow end. The outflow end has multiple V-shaped structures, each consisting of two connected wave rods, with each wave rod deflecting around itself. The second region has a tubular structure, and the axial middle position of the second region includes a valve annulus mounting area for fixing to the native valve annulus. This disclosure also proposes an artificial valve device, comprising a valve stent as described above and an artificial valve leaflet. The artificial valve leaflet is connected to the inner surface of the valve stent and is at least fixed in the transition region between the first and second regions. According to embodiments of this disclosure, the outflow end of the valve stent can vortex and radially contract slightly inward as the artificial heart valve opens and closes, thereby significantly reducing stress at the valve leaflet and reducing the potential risk of valve leaflet calcification.

Description

Technical Field

[0001] This disclosure relates to a medical device, and more particularly to a valve stent and artificial valve device for transcatheter valve replacement. Background Technology

[0002] Heart valves are a core component of the heart. During the heart's function, the heart valves constantly open and close to achieve normal blood circulation. When the valves mutate due to congenital or acquired diseases, causing them to be unable to open and close normally, it will have a significant impact on a person's health and life. Severe valvular diseases that cause the heart to malfunction require the replacement of artificial heart valves.

[0003] Currently, artificial biological heart valves are mainly used, and they are mainly divided into surgical implantation type and transcatheter interventional type based on the characteristics of implantation in the human body. Transcatheter interventional artificial biological heart valves involve pre-loading the valve into a catheter, and then using a valve delivery device to implant the valve into the designated position through the aorta or the apical ostium. This method has advantages such as short operation time, no need to stop the heart, and less blood loss, significantly reducing trauma compared to surgical implantation artificial valves, and is becoming increasingly popular. However, transcatheter interventional artificial biological heart valves also have the problem of leaflet calcification, resulting in a maximum lifespan of only 10 years for current artificial biological heart valves. After the artificial biological valve fails, patients need to face a second surgery and corresponding risks. Summary of the Invention

[0004] To address the aforementioned issues, a valve stent and artificial valve device are provided, which employ an outflow end with a truncated cone structure and a flexible, deflectable wave rod, significantly reducing stress at the leaflet, thereby reducing the potential risk of leaflet calcification and improving product lifespan.

[0005] This disclosure discloses a valve stent composed of multiple rhomboid grids. Each rhomboid grid consists of four wave rods. The valve stent has a compressed state and an expanded state. A first region and a second region are sequentially connected along the axial direction of the valve stent from the outflow end to the inflow end. The first region has a truncated cone structure that tapers towards the outflow end, and the outflow end has multiple V-shaped structures, each consisting of two connected wave rods, with each wave rod deflected around itself. The second region has a tubular structure, and the axially intermediate position of the second region includes a valve annulus mounting area for fixation to the native valve annulus.

[0006] In one embodiment, the deflection angle of the wave rod is 2° to 10°.

[0007] In one embodiment, the two wave rods in the V-shaped structure deflect in the same direction.

[0008] In one embodiment, the valve stent is made of shape memory material or superelastic material.

[0009] In one embodiment, a transition region is provided between the first region and the second region, and the transition region is provided with at least two valve fixing holes along the circumference of the valve stent, and the at least two valve fixing holes are evenly distributed along the circumference of the valve stent.

[0010] In one embodiment, the diameter of the annulus mounting area is smaller than the diameter at other locations on the valve stent; and / or, the diamond grid of the annulus mounting area is smaller than the diamond grid at other locations on the valve stent.

[0011] In one embodiment, multiple radiopaque imaging points are distributed circumferentially along the valve stent in the valve annulus mounting area.

[0012] In one embodiment, the height of the valve stent is 28mm to 50mm; the diameter at the end of the outflow end of the first region is 20mm to 30mm; and the diameter of the valve annulus mounting area is 18mm to 28mm.

[0013] This disclosure also proposes an artificial valve device comprising a valve stent as described in any of the embodiments above and an artificial leaflet. The artificial leaflet is connected to the inner surface of the valve stent and is at least fixed in the transition region between the first region and the second region.

[0014] In one embodiment, the valve stent is configured such that as the artificial leaflet closes, the deflection angle of the wave rod increases and the radial dimension of the first region decreases.

[0015] According to embodiments of the present disclosure, the outflow end of the valve stent can form a vortex shape and slightly contract radially inward as the artificial heart valve opens and closes, thereby significantly reducing stress at the leaflet, reducing the potential risk of leaflet calcification deposition, improving the therapeutic effect of the artificial valve device, and extending its service life. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of this disclosure, the accompanying drawings of the embodiments will be briefly described below. Obviously, the drawings described below only relate to some embodiments of this disclosure and are not intended to limit this disclosure.

[0017] Figure 1 This is a schematic diagram of a valve stent 100 according to an embodiment of the present disclosure.

[0018] Figure 2a This is a top view of a first region 120 according to an embodiment of the present disclosure when the artificial leaflet is open.

[0019] Figure 2bThis is a top view of a first region 120 according to an embodiment of the present disclosure when the artificial leaflet is closed. Detailed Implementation

[0020] The technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. Based on the embodiments of this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.

[0021] Unless otherwise defined, all terms (including technical and scientific terms) used in the embodiments of this disclosure shall have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains. It should also be understood that terms such as those defined in a common dictionary shall be interpreted as having a meaning consistent with their meaning in the context of the relevant art, and shall not be interpreted in an idealized or highly formalized sense, unless expressly defined in the embodiments of this disclosure.

[0022] The terms "first," "second," and similar terms used in the embodiments of this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, terms such as "an," "a," or "the" do not indicate a quantity limitation, but rather indicate the presence of at least one. Likewise, terms such as "including" or "comprising" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. In the following description, spatial and orientational terms such as “upper,” “lower,” “front,” “rear,” “top,” “bottom,” “vertical,” and “horizontal” may be used to describe embodiments of the invention. However, it should be understood that these terms are merely for the convenience of describing the embodiments shown in the figures and do not require the actual device to be constructed or operated in a specific orientation. In the following description, the use of terms such as “connect,” “link,” “fix,” and “attach” can refer to a direct connection between two elements or structures without other elements or structures, or to an indirect connection between two elements or structures via an intermediate element or structure, unless otherwise expressly stated herein. It should be noted that “rhombus” in this document can refer to a rhomboid structure or a quadrilateral structure that approximates a rhombus. “Wave rod” in this document is a basic component forming the grid of the valve stent, which can be a straight rod or a rod with a certain curvature. The term “outflow end” as used herein refers to the end through which blood flows through the valve; “inflow end” refers to the end through which blood flows into the valve. Taking the aortic valve as an example, the outflow end is the side closer to the aortic arch, and the inflow end is the side closer to the left ventricle.

[0023] Currently available transcatheter aortic valve implantation (TAVI) stent systems, such as Venus-A and J-Valve, use self-expanding stents as the support frame, with bio-tissue valves (bovine or porcine pericardium) sutured to the inner wall of the frame. This design offers excellent performance and ease of use, and is widely accepted by clinical experts. However, bio-tissues have drawbacks, including susceptibility to calcification and short lifespan. After a certain number of years of use, TAVI systems may fail, requiring a second surgery, which poses significant risks to patients.

[0024] Therefore, embodiments of this disclosure provide a valve stent and an artificial valve device to solve the above-mentioned technical problems, as detailed in the following description.

[0025] Figure 1 This is a schematic diagram of a valve stent 100 according to an embodiment of the present disclosure. As shown in the figure, the valve stent 100 is composed of multiple rhomboid grids 110, each rhomboid grid 110 consisting of four wave rods 122, and each rhomboid grid is expandable. "Expandable" here means that the area of ​​the rhomboid grids 110 can increase and decrease accordingly when the valve stent 100 expands and contracts radially. The valve stent 100 has a compressed state and an expanded state. A first region 120 and a second region 130 are sequentially connected along its axial direction from the outflow end to the inflow end of the valve stent 100. The first region 120 has a truncated cone structure that tapers towards the outflow end. This truncated cone structure is, for example, a frustum (or truncated cone), a truncated pyramid, or the like. In one embodiment, the truncated cone structure is a frustum, as shown in the figure. The second region 130 has a tubular structure, and the axially intermediate position of the second region 130 includes a valve annulus mounting area 140 for fixing to the native valve annulus. As shown in the figure, the diameter of the annulus mounting region 140 is smaller than the diameter at other locations on the valve stent. The size of the rhomboid mesh 110 located in the annulus mounting region 140 is smaller than the size of the rhomboid mesh 110 at other locations on the valve stent 100, so that the mesh density of the annulus mounting region 140 is greater than the mesh density at other locations on the valve stent 100. The radial support strength of the valve stent 100 composed of rhomboid mesh 110 largely depends on its mesh density. When the mesh density is higher, the radial support force of the valve stent 100 is greater, so that the annulus safety zone of the valve stent 100 can fit more firmly onto the aortic valve annulus. It should be noted that "mesh density" in this article refers to the number of meshes per unit area. "Size" mainly refers to the area of ​​the rhomboid mesh.

[0026] The outflow end has multiple V-shaped structures 124, each consisting of two connected wave rods 122. At least two of the V-shaped structures 124 have T-shaped connecting rods 128 at their proximal ends. The number of T-shaped connecting rods 128 can be adjusted according to actual needs. In one embodiment, as shown, there are three T-shaped connecting rods 128, evenly distributed circumferentially along the valve stent 100. Each T-shaped connecting rod 128 includes a rod extending circumferentially along the valve stent at its outflow end. In one embodiment, the rod at the outflow end of the T-shaped connecting rod 128 has an arc-shaped structure bent around the central axis of the valve stent, ensuring sufficient contact between the valve stent 100 and the fixed anchor of the delivery system under compression. This significantly reduces the profile diameter at the contact point through localized structure, further facilitating the safe anchoring of the valve system into the catheter. Furthermore, due to its arc-shaped structure design, it effectively ensures timely release and disengagement while maintaining safe anchoring, reducing hooking phenomena during valve release during surgery.

[0027] The wave rod 122 of this disclosure is flexible and has deflection characteristics, meaning that the wave rod 122 can deflect circumferentially. During cardiac systole and diastole, when the native aortic valve annulus contracts with the contraction of the left ventricle, the valve stent 100 contracts radially inward, thereby driving the wave rod 122 to further deflect circumferentially, increasing the deflection angle. To avoid stent displacement, existing valve stents are typically designed with high radial support force; for example, a crown-like structure is used at the outflow end of the valve stent, resulting in high overall rigidity. When the heart contracts and the leaflets close, the valve stent still tends to expand radially outward, leading to stress concentration on the leaflets, which easily causes calcification and affects the lifespan of the leaflets. Compared to the traditional crown-like structure design, the truncated cone design of this disclosure has a smaller diameter at the outflow end of the valve stent 100 and uses less metal material, thus giving the valve stent 100 the necessary rigidity (support) while also possessing a certain degree of flexibility. In other words, the valve stent 100 of this disclosure is more flexible than existing (crown-type) valve stents with higher rigidity. During cardiac systole and diastole, the diameter of the native aortic valve annulus increases or decreases accordingly, thereby changing the radial dimension of the self-expanding valve stent 100 that is tightly attached to the native aortic valve annulus. For example, when the heart contracts, the diameter of the aortic valve annulus decreases, and thus the diameter of the valve stent 100 (especially the diameter at the outflow tract) also decreases accordingly. In other words, the aortic vessels surrounding the aortic valve and the left ventricular wall exert radial forces on the valve stent 100 to which it is attached, thereby reducing the radial diameter of the valve stent 100. It should be noted that the wave rod 122 is flexible, allowing it to slightly retract radially inward during valve closure. On the other hand, the native aortic valve annulus and blood vessels exert a circumferential force on the valve stent 100. Since the valve stent 100 of this disclosure has a certain degree of flexibility, this force causes the proximal portion of the valve stent 100, which is in close contact with the aortic wall, to deflect circumferentially. In other words, the wave rod 122 in the first region 120 deflects circumferentially along the valve stent 100. Therefore, in actual operation, when the implanted artificial valve leaflet closes, it pulls the wave rod 122 in the first region 120 slightly in the radial direction of the valve stent 100 at a certain deflection angle, allowing the outflowing wave rod 122 to move locally with the opening and closing of the heart valve. This transfers the stress generated by the pressure gradient from the artificial valve leaflet (which, as a biomaterial, has unpredictable properties) to the valve stent 100 (which, as a synthetic material, has isotropic properties and predictable mechanical properties), thereby significantly reducing the stress at the valve leaflet and lowering the potential risk of valve leaflet calcification.It should be noted that although the native aortic valve annulus and blood vessels exert circumferential forces on the valve stent 100, traditional crown stents are relatively difficult to contract, resulting in stress concentration on the leaflets. In summary, when the outflow end of the wave rod 122 deflects, it also moves simultaneously in the circumferential and radially inward directions along the valve stent 100. At this time, the distal end of the wave rod 122 in the first region 120 (the end closer to the inflow end) is restricted in its movement due to its connection with the second region 130. Therefore, each wave rod 122 simultaneously deflects, tilts, and bends, causing the outflow end of the valve stent 100 to form a vortex shape and slightly contract radially inward, releasing the stress accumulated on the leaflets. It should be noted that "deflection" in this article refers to the outflow end of the wave rod twisting along its own circumference, not to the wave rod transforming into a bent shape.

[0028] In one embodiment, the first region 120 has six V-shaped structures 124, three of which have T-shaped connecting rods 128 at their proximal ends. These T-shaped connecting rods 128 are evenly distributed circumferentially along the valve stent 100, and each T-shaped connecting rod 128 includes a rod 129 extending circumferentially along the valve stent at its outflow end. The wave rod 122 deflects along its own axis. Taking the aortic valve as an example, when the left ventricle contracts, blood flows through the valve to the aorta, and the leaflets fixed to the valve stent 100 open. At this time, the wave rod 122 is in its initial position, such as... Figure 2a As shown, when the diameter of the aortic valve annulus decreases, the aortic vessels surrounding the aortic valve annulus and the left ventricular wall exert radial and circumferential forces on the valve stent 100 attached to it. This causes the outflow end of the wave rod 122 to move inward along both the circumferential and radial directions of the valve stent 100 as it deflects. In other words, when the artificial valve leaflet closes, it pulls the wave rod 122 slightly inward in the radial direction of the valve stent 100 at a certain deflection angle α, allowing the wave rod 122 to move locally with the opening and closing of the heart valve. At this time, each wave rod 122 simultaneously deflects, tilts, and bends, as shown... Figure 2b As shown, this causes the outflow end of the valve stent 100 to form a vortex shape and slightly taper radially inward. The deflection angle is the same as the position deflection angle α of the rod 129, thereby releasing the stress accumulated on the leaflet. In one embodiment, the deflection angle of the wave rod is 2° to 10° in its natural state. In one embodiment, the two wave rods in the V-shaped structure 124 deflect in the same direction, for example, both deflect clockwise or both deflect counterclockwise.

[0029] In one embodiment, the valve stent 100 may be made of a shape memory material or a hyperelastic material. The shape memory material is, for example, a nickel-titanium alloy, preferably nitinol. Using this material, the valve stent 100 can expand from a contracted state to an extended state, which can be achieved, for example, by applying heat, other energy, or by removing external forces (e.g., compressive forces). The valve stent 100 can be repeatedly compressed and re-expanded without damaging the stent structure. Furthermore, the valve stent 100 may be laser-cut from a single tubular material or assembled from separately formed wavelets.

[0030] A transition region is provided between the first region 120 and the second region 130, and at least two valve fixation holes 126 are provided in this transition region along the circumference of the valve stent 100. The at least two valve fixation holes 126 are evenly distributed along the circumference of the valve stent 100. The number of valve fixation holes 126 can be determined according to the number of valve leaflets. In one embodiment, the valve device is used for aortic valve replacement surgery, and the number of leaflets (not shown) is three, then the corresponding number of valve fixation holes 126 is three. It should be noted that the three leaflets in the valve are connected to the inner surface of the valve stent 100 and fixed to the valve fixation holes 126 at the transition region.

[0031] In one embodiment, a plurality of radiopaque radiopaque points 132 are distributed circumferentially in the annulus mounting region 140 of the valve stent 100, corresponding to the original valve annulus location. This ensures good radiopaqueness of the valve stent 100 or the entire valve device during implantation, improves the positioning accuracy of the valve stent 100 during release, reduces surgical time, and thus lowers surgical risks. The radiopaque radiopaque points 134 are made of materials such as gold or a platinum-iridium alloy. In one embodiment, the number of radiopaque points 132 can be set to 2-6, depending on actual needs and the size of the valve stent.

[0032] In one embodiment, the height of the valve stent 100 can be 28–50 mm, depending on the actual surgical needs. To ensure the support of the valve stent, conventional valve stent structures are generally quite tall, ranging from 40–65 mm, and require a crown-like structure design with a large outer diameter at the outlet portion. After implantation at the lesion site, this type of valve stent can easily affect the original hemodynamics of the heart valve, and may even obstruct branch vessels. The long overall length of the valve and the high position of the leaflets can affect coronary artery perfusion, leading to a higher incidence of thrombosis. As described above, according to this disclosure, by providing an annulus mounting area 140 on the valve stent 100 and increasing its mesh density, the radial support force in this area is increased, allowing the annulus safety area 140 of the valve stent 100 to fit more firmly onto the aortic valve annulus. Therefore, the valve stent 100 can be securely installed in the aortic valve position without the need for a crown-style outflow end design. This significantly reduces the size of the valve stent 100, simplifies the stent structure, reduces the amount of metal material used, and thus reduces related complications. Here, "height" refers to the dimension along the axial direction of the valve stent 110.

[0033] Based on the actual surgical requirements for the structural dimensions of the valve stent 100, a further optimized design of the valve stent 100 can be selected. In one embodiment, the diameter at the outflow end of the first part is 20–30 mm, meaning the minimum diameter range of the truncated cone structure is 20–30 mm. Compared to the traditional crown-type outflow end design, the truncated cone structure design can further reduce the compression diameter of the valve stent 100, thereby reducing the outer diameter of the artificial valve device. Based on the physiological and anatomical characteristics of the patient population, if the patient's blood vessels are thin, the diameter range of the truncated cone structure can be specifically designed, which is not possible with the traditional crown-type structure. This is because the traditional crown-type structure has a large outer diameter at the outflow end and uses a large amount of metal; however, choosing a smaller size would lead to insufficient stent support performance, paravalvular leakage, and other problems. In one embodiment, the diameter at the annulus mounting region 140 is 18 mm–28 mm. As mentioned above, the diamond-shaped mesh 110 at the annulus mounting region 140 has the highest density, meaning the greater the number of meshes per unit area, the greater the radial force in the annulus mounting region 140. Because the aortic valve size varies among patients, the radial force required for the annulus mounting region 140 to securely mount the valve stent 110 onto the native annulus also differs. Therefore, appropriate aortic valve sizes can be designed and selected for different patient groups, and the diameter of the annulus mounting region 140 can be adjusted to provide sufficient radial force, facilitating better mounting and fixation of the valve stent 100 at the aortic valve location. Furthermore, based on the physiological and anatomical characteristics of different patient groups, the local dimensions of the valve stent 110 can be fine-tuned within the aforementioned size range to adapt to different aortic valve structures.

[0034] Based on the foregoing, this disclosure also provides an artificial valve device. The artificial valve device includes the aforementioned valve stent 100 and artificial leaflets. The artificial leaflets are connected to the inner surface of the valve stent 100 and are at least fixed to the transition region between the first region 120 and the second region 130. In one embodiment, the valve stent 100 is configured such that as the artificial leaflets close, the deflection angle of the wave rod increases, and the radial dimension of the first region 120 decreases. In the artificial valve device according to embodiments of this disclosure, the valve stent 100 exhibits greater flexibility compared to a more rigid (crown-type) valve stent. During cardiac contraction and leaflet closure, the native aortic valve annulus and blood vessels exert circumferential and radially inward forces on the valve stent 100, thereby reducing the radial diameter of the valve stent 100. In this way, when the outflow end of the flexible wavelet 122 deflects, it also moves simultaneously in the circumferential and radially inward directions along the valve stent 100. This causes each wavelet 122 to deflect, tilt, and bend simultaneously, resulting in the outflow end of the valve stent 100 forming a vortex shape and slightly contracting radially inward. This releases the stress accumulated on the valve leaflets, thereby significantly reducing the stress at the valve leaflets, lowering the potential risk of leaflet calcification, and extending the lifespan of the valve leaflets. It should be noted that the valve stent and artificial valve device disclosed herein can be used not only for aortic valves but also for other valves, such as mitral and tricuspid valves.

[0035] The following points need to be explained:

[0036] (1) The accompanying drawings of the embodiments of this disclosure only involve the structures involved in the embodiments of this disclosure. Other structures can be referred to the general design.

[0037] (2) Where there is no conflict, the embodiments of this disclosure and the features in the embodiments can be combined with each other to obtain new embodiments.

[0038] The above are merely specific embodiments of this disclosure, but the scope of protection of this disclosure is not limited thereto. The scope of protection of this disclosure shall be determined by the scope of the claims.

Claims

1. A prosthetic valve device, characterized by, The artificial valve device includes: A valve stent (100) is composed of multiple rhomboid grids (110), each rhomboid grid (110) consisting of four wave rods (122). The valve stent (100) has a compressed state and an expanded state. A first region (120) and a second region (130) are sequentially connected along the axial direction of the valve stent from the outflow end to the inflow end. The first region (120) has a truncated cone structure that tapers toward the outlet end, the outlet end having a plurality of V-shaped structures (124), each V-shaped structure being composed of two connected wave rods, each wave rod having a deflection structure around itself. The second region (130) has a tubular structure, and the axially intermediate position of the second region (130) includes a valve ring mounting area (140) for fixing to the original valve ring; and Artificial leaflet, the artificial leaflet being connected to the inner surface of the valve stent (100) and at least fixed to the transition region between the first region (120) and the second region (130); The valve stent (100) is configured as follows: Under natural conditions, the deflection angle of the wave rod is 2° to 10°, and, When the artificial leaflet closes, each of the wave rods simultaneously deflects, tilts, and bends.

2. The artificial valve device according to claim 1, characterized in that, The two wave rods in the V-shaped structure (124) deflect in the same direction.

3. The artificial valve device according to claim 1, characterized in that, The valve stent (100) is made of shape memory material or superelastic material.

4. The artificial valve device according to claim 1, characterized in that, A transition region is provided between the first region (120) and the second region (130). The transition region is provided with at least two valve fixing holes (126) along the circumference of the valve stent (100). The at least two valve fixing holes (126) are evenly distributed along the circumference of the valve stent (100).

5. The artificial valve device according to claim 1, characterized in that, The diameter of the annulus mounting area (140) is smaller than the diameter at other locations on the valve stent; and / or, The size of the rhomboid grid (110) in the valve annulus mounting area (140) is smaller than the size of the rhomboid grid (110) at other locations on the valve stent.

6. The artificial valve device according to claim 1, characterized in that, Multiple radiopaque imaging points (132) are distributed circumferentially along the valve stent in the valve annulus mounting area (140).

7. The artificial valve device according to claim 1, characterized in that, The height of the valve stent (100) is 28mm~50mm; The diameter at the end of the outflow end of the first region (120) is 20mm~30mm; The diameter of the valve ring mounting area (140) is 18mm~28mm.

8. The artificial valve device according to any one of claims 1-7, characterized in that, The valve stent (100) is configured such that as the artificial leaflet closes, the deflection angle of the wave rod increases and the radial dimension of the first region (120) decreases.

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