An absorbable valve stent and valve prosthesis

Abstract

This invention relates to the field of medical device technology, and more particularly to an absorbable valve stent and a valve prosthesis including the absorbable valve stent. The absorbable valve stent includes an inner stent and an outer stent disposed on the outer periphery of the inner stent. The outer stent includes a main body segment and a valve annulus segment connected together. The main body segment is used to match the atrium, and the valve annulus segment is used to match the valve annulus. The bottom of the valve annulus segment is connected to the bottom of the inner stent via a connecting frame. The main body segment is composed of a first rod, which is either a non-fully absorbable rod or entirely made of a biodegradable absorbable material. The non-fully absorbable rod includes an inner core made of a non-biodegradable absorbable material and an outer sheath made of a biodegradable absorbable material that wraps around the inner core. After implantation, the support force of the main body segment on the atrium is weakened by the degradation and absorption of the outer sheath, or the support of the atrium is relieved by the complete degradation and absorption of the main body segment, allowing the atrium to restore normal contractility.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, and in particular to an absorbable valve stent and a valve prosthesis including the absorbable valve stent. Background Technology

[0002] The heart is a vital organ, and the heart valves primarily ensure the smooth unidirectional flow of blood between the heart's chambers, thus pumping blood throughout the body and maintaining the normal function of all cells. If the valves malfunction, such as through calcification or damage, resulting in incomplete closure and regurgitation, or if the opening narrows, they cannot guarantee a normal blood supply, leading to decreased bodily function, affecting quality of life, and even endangering life. The mitral valve, located between the left atrium and left ventricle, consists of four parts: leaflets, annulus, chordae tendineae, and papillary muscles. Normal mitral valve function depends on the integrity of these four parts and the structure and function of the left ventricle. Any structural abnormality or functional disorder in any one or more of these parts can lead to mitral regurgitation, causing blood to flow backward into the left atrium during left ventricular contraction. This results in insufficient arterial blood from the ventricle flowing into the systemic circulation, affecting blood supply. Mitral regurgitation can be classified as primary or secondary. Primary mitral regurgitation is usually caused by structural and functional changes in the leaflets, annulus, chordae tendineae, and papillary muscles, and treatment typically targets these abnormal structures. Many patients with moderate to severe regurgitation may require surgery, such as mitral valve repair or replacement. Secondary mitral regurgitation is primarily caused by atrioventricular dilatation, and treatment strategies mainly focus on treating heart failure and reducing the annular diameter. Mitral regurgitation increases the workload on the left ventricle, leading to increased pressure in the pulmonary veins and pulmonary capillaries, causing dilation and congestion. Long-term regurgitation can lead to compensatory enlargement of the left ventricle and left atrium, ultimately resulting in heart failure. Treatment for mitral regurgitation includes surgical repair and interventional procedures. Surgical repair is not suitable for older patients or those with weakened cardiac function. Interventional procedures are becoming increasingly popular due to their shorter operation time, less bleeding, and faster recovery. Currently, interventional procedures mainly include mitral valve leaflet repair and mitral valve replacement. Mitral valve leaflet repair uses assistive devices to correct leaflet insufficiency, reducing or eliminating regurgitation, including leaflet clips, chordae tendineae repair, and annular constriction. Mitral valve replacement eliminates regurgitation by implanting a valve prosthesis, such as Medtronic's Intrepid, Abbott's Tendyne, Edwards' EVOQUE, and 4C Medical's Altavalve.

[0003] For mitral valve replacement products, the biggest challenge is securing the prosthesis to the mitral valve annulus while minimizing paravalvular leakage and impact on the aorta. Medtronic's Intrepid, for example, features a dual-layer stent design including a circular inner stent to accommodate the bioprosthetic valve and a flexible outer stent to anchor the mitral valve annulus. The outer stent is designed to accommodate the variability of the patient's own mitral valve annulus and isolates the inner valve annulus assembly throughout the cardiac cycle, ensuring the internal valve remains undisturbed. During ventricular contraction, the implanted prosthesis experiences forces from the left ventricle to the left atrium. Due to the immense ventricular pressure, the impact force is also very large, posing a significant challenge to prosthesis fixation. The Intrepid product, due to the flexible design of the outer stent, has relatively low radial support and relies primarily on barbed structures on the outer stent for fixation to prevent displacement. This makes the release process highly demanding and complex. Abbott's Tendyne product primarily relies on ventricular fixation components for stent fixation and can only be released transapically. 4C Medical's Altavalve fixes the mitral valve prosthesis by using atrial fixation and annular fixation. The atrium is opened by the stent to provide axial support. The advantages of Altavalve are high reliability of atrial fixation, simple release, and short operation time.

[0004] Atrial fixation is a method of implanting and fixing mitral and tricuspid valve prostheses, but it also has several drawbacks: First, in patients with regurgitation, the atrial pressure increases, causing the atria to enlarge. After successful valve prosthesis implantation, the degree of regurgitation may decrease, or the atrial pressure may drop. Normally, the atria would recoil, but due to the implantation of the atrial stent, atrial recoil is restricted, affecting the recovery of atrial function. Second, the long-term presence of a stent in the atrium can affect the normal contractile function of the atrium. Third, the long-term presence of a stent in the atrium can affect some subsequent interventional procedures in the atrium, such as atrial ablation. Summary of the Invention

[0005] In view of the above-mentioned deficiencies of the prior art, the technical problem to be solved by the present invention is to provide an absorbable valve stent that can restore the normal contractility of the atrium through the degradation and absorption of the stent after implantation.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0007] This invention provides an absorbable valve stent, comprising an inner stent and an outer stent disposed on the outer periphery of the inner stent. The outer stent includes a main body segment and a valve annulus segment connected together. The main body segment is used to match the atrium, and the valve annulus segment is used to match the valve annulus. The bottom of the valve annulus segment is connected to the bottom of the inner stent through a connecting frame. The main body segment is composed of a first rod, which is either a non-fully absorbable rod or entirely made of a biodegradable absorbable material. The non-fully absorbable rod includes an inner core made of a non-biodegradable absorbable material and an outer sheath made of a biodegradable absorbable material that wraps around the inner core.

[0008] Preferably, the annular segment, the connecting frame, and the inner stent are all composed of a second rod, which is a non-fully absorbable rod or is made entirely of a non-degradable absorbable material; preferably, both the first and second rods are non-fully absorbable rods made of the same material, and the absorbable valve stent is a single integral piece; preferably, the second rod is made entirely of a non-degradable absorbable material, and the diameter, rod width, or wall thickness of the second rod is 0.3mm-1mm.

[0009] Preferably, the degradation cycle of the biodegradable absorbent material is longer than the endothelialization cycle of the valve annulus segment; preferably, the degradation cycle of the biodegradable absorbent material is more than 6 months.

[0010] Preferably, the main body segment and the petal ring segment are connected by a connecting structure and / or welding or by hot melting; preferably, the connecting structure is an interference fit connecting structure or a riveted connecting structure; preferably, protrusions and grooves are respectively provided on the end faces of the main body segment and the petal ring segment, the protrusions and grooves are interference fit, or the protrusions and grooves are gap fit and welded to reinforce the joint between the main body segment and the petal ring segment.

[0011] Preferably, the biodegradable absorbent material is polylactic acid, polycaprolactone, polyglycolic acid, polyanhydride, polycarbonate, polyurethane, polyphosphate, polyorthoester, magnesium-based alloy, zinc-based alloy, or iron-based alloy.

[0012] Preferably, the width, diameter, or wall thickness of the first rod is 1 to 2.5 times larger than that of the metal support rod; or, when the first rod is made entirely of a biodegradable absorbent material, the diameter, width, or wall thickness of the first rod is 0.5 mm to 2.5 mm; or, when the first rod is made entirely of a biodegradable absorbent material, and the degradation period of the biodegradable absorbent material is 8 to 10 months, the diameter, width, or wall thickness of the first rod is 1 mm or more.

[0013] Preferably, both the inner and outer supports adopt a mesh structure, with the mesh size of the inner support being 5mm-10mm and the mesh size of the outer support being 0.4 to 0.8 times smaller than that of the metal mesh outer support; preferably, the mesh size of the main body section of the outer support is 2mm-20mm.

[0014] Preferably, any one or a combination of the following strengthening measures is adopted:

[0015] Strengthening Measure 1: The main body segment is equipped with a reinforcing rib structure; preferably, a reinforcing rib structure is added in the bending area of ​​the main body segment or at the key node connecting the main body segment and the valve annulus segment; preferably, the cross-sectional shape of the reinforcing rib structure is triangular or rectangular; preferably, the first rod is made entirely of a biodegradable absorbable material, the cross-sectional shape of the reinforcing rib structure is triangular, the height of the reinforcing rib structure is 0.5 to 1 times the diameter, width, or wall thickness of the first rod, and the thickness of the reinforcing rib structure is 0.3 to 0.6 times the diameter, width, or wall thickness of the first rod, thereby reducing the maximum stress of the main body segment when subjected to simulated blood flow impact force and cardiac contraction force by 20%-35%;

[0016] Strengthening Measure 2: A biodegradable support is nested within the main body section; preferably, the biodegradable support is a ring-shaped or spherical mesh structure; preferably, the biodegradable support is arranged directly opposite or staggered from the main body section;

[0017] Strengthening Measure 3: The first component includes the core and the cover that wraps around the core. The cover is made of a biodegradable absorbent material, and the core is made of a non-biodegradable metal memory wire or a biodegradable absorbent alloy or composite material that is harder than the cover.

[0018] Fourthly, the main body section is woven with braided yarn and bound and fixed at the braided joints with biodegradable and absorbable stitching.

[0019] Fifthly, barbed structures are provided on the annular segment.

[0020] Preferably, along the axial direction of the absorbable valve stent, the height of the main body segment accounts for 30%-70% of the overall height of the absorbable valve stent.

[0021] The present invention also provides a valve prosthesis, comprising an absorbable valve stent, leaflets and a skirt membrane as described above, wherein the leaflets are disposed on the inner stent and the skirt membrane is disposed on the annular segment of the inner stent and the outer stent.

[0022] Compared with the prior art, the present invention has significant progress:

[0023] The absorbable valve stent of this invention is designed in segments: a main body segment and a valve annulus segment. The main body segment is designed to be partially or completely biodegradable and absorbable. This allows the main body segment to initially fix the absorbable valve stent within the atrium after implantation, preventing displacement and ensuring effective endothelialization. Subsequently, either the main body segment's epithelial degradation weakens its support for the atrium, allowing the atrium to regain some contractile function. After regurgitation decreases or disappears, the atrial size can also shrink to some extent, restoring normal atrium contractility. Alternatively, complete degradation and absorption of the main body segment relieves the atrium's support, allowing atrial contraction to return to normal. After regurgitation decreases or disappears, the atrial size will also decrease, gradually returning to normal size, and cardiac function will gradually recover. The main body of the external stent is completely biodegradable and absorbable, and also has the following advantages: it can avoid the risk of complications caused by the long-term retention of the main body of the external stent in the atrium; it can preserve the operating space for subsequent interventional treatments in the atrium and avoid restricting subsequent surgeries; it can perform multiple interventional interventions at the same lesion in the atrium without the problems caused by stent overlap; it avoids the bleeding risk caused by long-term use of dual antiplatelet drugs; and it is more suitable for children or adolescents, as it can avoid restricting the growth and development of the atrium itself. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of the absorbable valve stent according to an embodiment of the present invention.

[0025] Figure 2 This is a schematic diagram of the implantation of an absorbable valve stent according to an embodiment of the present invention.

[0026] Figure 3 This is a schematic diagram of one embodiment of the connection structure between the main body segment and the valve annulus segment of the absorbable valve stent according to an embodiment of the present invention.

[0027] Figure 4 This is a schematic diagram of another embodiment of the connection structure between the main body segment and the valve annulus segment of the absorbable valve stent in this invention.

[0028] Figure 5 This is a schematic diagram of an absorbable valve stent according to an embodiment of the present invention, in which a biodegradable stent is nested within the main body segment of the outer stent.

[0029] Figure 6 This is a schematic diagram of the structure of the valve prosthesis according to an embodiment of the present invention.

[0030] The reference numerals in the attached figures are explained as follows:

[0031] 100 absorbable valve stents

[0032] 1. Internal support

[0033] 2 External support

[0034] 21 Main body paragraphs

[0035] 22-petal annular segment

[0036] 221 Atrial contact area

[0037] 222 Lobe Annulus Contact Section

[0038] 3 Connecting bracket

[0039] 41 First member

[0040] 42 Second member

[0041] 5. Connection Structure

[0042] 51 protrusions

[0043] 52 Grooves

[0044] 53 Connecting holes

[0045] 54 Rivets

[0046] 6 Biodegradable scaffolds

[0047] 200 petals

[0048] 300 skirt edge membrane

[0049] 400 connector Detailed Implementation

[0050] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. These embodiments are for illustrative purposes only and are not intended to limit the scope of the invention.

[0051] In the description of this invention, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0052] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0053] Furthermore, in the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0054] like Figures 1 to 5 The image shows an embodiment of the absorbable valve stent provided by the present invention.

[0055] See Figure 1 and Figure 2 The absorbable valve stent 100 of this embodiment includes an inner stent 1, an outer stent 2, and a connecting frame 3. The outer stent 2 is disposed on the outer periphery of the inner stent 1, forming an inner and outer double-layer stent structure. The bottom of the outer stent 2 and the bottom of the inner stent 1 are connected by the connecting frame 3 to form a ball cage.

[0056] The inner support 1 is used to fix the artificial leaflet. The inner support 1 is preferably a cylindrical mesh structure, but the structure of the inner support 1 is not limited, and can be any one or more combinations of mesh structure, arc structure, quadrilateral structure, hexagonal structure, straight rod structure and woven structure.

[0057] The external stent 2 is used to anchor the valve annulus (such as the mitral or tricuspid valve annulus) and the atrium (such as the left or right atrium), providing anchorage and forming a fixation method that combines atrial fixation and valve annulus fixation. This ensures stable anchorage and avoids problems such as paravalvular leakage, radial compression of the valve annulus leading to deformation of the internal stent 1, and axial slippage of the internal stent 1 due to blood flow impact. The structural form of the external stent 2 is not limited; it can be any combination of one or more of the following: a curved rod structure, a grid unit structure, an arc structure, a quadrilateral structure, a hexagonal structure, and a braided structure.

[0058] The external stent 2 includes a main body segment 21 and a valve annulus segment 22 connected together. The main body segment 21 is used to match the atrium, and the valve annulus segment 22 is used to match the valve annulus. The valve annulus segment 22 is connected to the bottom of the main body segment 21, and the bottom of the valve annulus segment 22 is also the bottom of the external stent 2. The bottom of the valve annulus segment 22 is connected to the bottom of the internal stent 1 through a connecting frame 3. The shape of the main body segment 21 of the external stent 2 is a spherical shape that matches the shape of the atrial chamber, and the shape of the valve annulus segment 22 is a cylindrical shape or a cross-sectional shape with a similar D-shape that matches the shape of the valve annulus. Preferably, the valve annulus segment 22 includes an atrial contact portion 221 and a valve annulus contact portion 222 connected sequentially from the main body segment 21 to the connecting frame 3. The atrial contact portion 221 is used to contact the bottom of the atrium, and the valve annulus contact portion 222 is used to contact the valve annulus. The atrial contact portion 221 and the main body segment 21 together form a spherical or spherical shape that approximates the shape of the atrial chamber. After implantation, the spherical or near-spherical shape formed by the main body segment 21 of the external stent 2 and the atrial contact portion 221 of the valve annulus segment 22 fits against the atrial wall and is tightly wrapped by the atrium, so that the atrium generates an anchoring force on the absorbable valve stent 100, which plays a role in fixing the absorbable valve stent 100 and preventing the absorbable valve stent 100 from axially shifting or falling off when subjected to blood flow impact. The valve annulus segment 22 fits against the valve annulus through the valve annulus contact portion 222, providing radial support force and playing a role in fixing the internal stent 1. At the same time, the atrial contact portion 221 of the valve annulus segment 22 and the skirt membrane attached thereto work together to fit tightly against the valve annulus and the bottom of the atrium, thereby reducing blood leakage at the valve annulus.

[0059] In this embodiment, the main body segment 21 of the outer support 2 is composed of a first rod 41. The first rod 41 is made entirely of a biodegradable absorbable material, so that the main body segment 21 of the outer support 2 can be completely degraded and absorbed. Alternatively, the first rod 41 is a non-fully absorbable rod, which includes an inner core and an outer skin that wraps around the inner core. The inner core is made of a non-degradable absorbable material, and the outer skin is made of a biodegradable absorbable material, thereby allowing the main body segment 21 of the outer support 2 to be partially degraded and absorbed.

[0060] When the first rod 41 constituting the main body segment 21 is made entirely of a biodegradable and absorbable material, the main body segment 21 of the external stent 2 can be completely degraded and absorbed. After implantation, the main body segment 21 initially serves to fix the absorbable valve stent 100 within the atrium, preventing the absorbable valve stent 100 from displacing into the atrium and ensuring the initial endothelialization effect. Subsequently, the main body segment 21 will gradually degrade and be completely absorbed, relieving the support to the atrium, thereby allowing atrial contraction to return to normal. After regurgitation decreases or disappears, the atrial size will also decrease, gradually returning to normal size, and cardiac function will gradually recover. The complete degradability and absorption of the main body segment 21 of the external stent 2 also has the following advantages: it can avoid the risk of complications caused by the long-term retention of the main body segment 21 of the external stent 2 within the atrium; it can preserve the operating space for subsequent interventional treatments of the atrium, avoiding restrictions on subsequent surgeries; it allows for multiple interventional interventions at the same lesion site in the atrium without the problems caused by stent overlap; it avoids the bleeding risk caused by long-term use of dual antiplatelet drugs; and it is more suitable for children or adolescents, avoiding restriction on the growth and development of the atrium itself.

[0061] When the first rod 41 constituting the main body segment 21 is a non-fully absorbable rod, the outer skin of the main body segment 21 of the external stent 2 is degradable and absorbable, while the inner core is not. After implantation, the main body segment 21 can initially fix the absorbable valve stent 100 in the atrium, preventing the absorbable valve stent 100 from shifting into the atrium and ensuring the effect of early endothelialization. Subsequently, the outer skin of the main body segment 21 will gradually degrade. After the outer skin of the main body segment 21 is completely degraded and absorbed, only the non-degradable and absorbable inner core remains in the main body segment 21, which weakens the overall support of the main body segment 21 in the atrium. This allows the atrium to recover some of its contractile function. After the regurgitation is reduced or eliminated, the atrial size can also shrink to a certain extent, allowing the atrium to restore normal contractility.

[0062] In the absorbable valve stent 100 of this embodiment, preferably, the annular segment 22, the connecting frame 3, and the inner stent 1 of the outer stent 2 are all composed of a second rod 42. The second rod 42 is made entirely of a non-degradable absorbable material, so that the annular segment 22, the connecting frame 3, and the inner stent 1 of the outer stent 2 are all non-degradable and absorbable. Alternatively, the second rod 42 is a non-fully absorbable rod, which includes an inner core and an outer skin that wraps around the inner core. The inner core is made of a non-degradable absorbable material, and the outer skin is made of a degradable absorbable material, thereby allowing the annular segment 22, the connecting frame 3, and the inner stent 1 of the outer stent 2 to be partially degradable and absorbable.

[0063] When the annular segment 22, connecting frame 3, and second rod 42 of the inner stent 1 of the outer stent 2 are made of non-degradable absorbable material, the annular segment 22, connecting frame 3, and inner stent 1 of the outer stent 2 will not degrade or be absorbed after implantation, thus maintaining the absorbable valve stent 100 to replace the mitral or tricuspid valve and perform its function.

[0064] When the valve annulus segment 22, the connecting frame 3, and the second rod 42 of the inner stent 1 that constitute the outer stent 2 are non-fully absorbable rods, after implantation, the outer skin of the valve annulus segment 22, the connecting frame 3, and the inner stent 1 will gradually degrade away, while the inner core remains. The endothelialized inner core can also maintain the function of the absorbable valve stent 100 in replacing the mitral or tricuspid valve.

[0065] In this embodiment, the main body segment 21 of the outer stent 2 serves as the absorbable part of the absorbable valve stent 100, and the annular segment 22, the connecting frame 3, and the inner stent 1 of the outer stent 2 serve as the non-absorbable part of the absorbable valve stent 100. The absorbable part of the absorbable valve stent 100 can be completely biodegradable or partially biodegradable, and the non-absorbable part of the absorbable valve stent 100 can be completely non-biodegradable or partially biodegradable. The combination of the absorbable and non-absorbable parts of the absorbable valve stent 100 is not limited.

[0066] In the first embodiment, both the first rod 41 and the second rod 42 are not fully absorbable rods and are made of the same material, making the absorbable valve stent 100 a single, integrally molded component. This means that both the absorbable and non-absorbable portions of the absorbable valve stent 100 are partially biodegradable and absorbable, and are made of the same material. This ensures that the entire absorbable valve stent 100 is made of the same material, allowing for integral molding. This maintains the integrity of the absorbable valve stent 100 and eliminates the risks associated with the connection measures required for separate assembly of the absorbable and non-absorbable portions.

[0067] In the second embodiment, the first rod 41 is entirely made of a biodegradable absorbable material, and the second rod 42 is a non-fully absorbable rod. Preferably, the inner core of the second rod 42 transitions to a biodegradable absorbable material at the connection between the valve annulus segment 22 and the main body segment 21, and continues to extend from the outer skin to cover and form the first rod 41. Thus, the absorbable portion of the absorbable valve stent 100 is fully biodegradable, and the non-absorbable portion of the absorbable valve stent 100 is partially biodegradable.

[0068] In the third embodiment, the first rod 41 is entirely made of a biodegradable absorbable material, and the second rod 42 is entirely made of a non-biodegradable absorbable material. The first rod 41 and the second rod 42 are connected to each other at the junction of the annular segment 22 and the main body segment 21. Thus, the absorbable portion of the absorbable valve stent 100 is completely biodegradable, and the non-absorbable portion of the absorbable valve stent 100 is completely non-biodegradable.

[0069] In the fourth embodiment, the first rod 41 is a non-fully absorbable rod, and the second rod 42 is entirely made of a non-degradable absorbable material. Preferably, the outer skin of the first rod 41 transitions to a non-degradable absorbable material at the connection between the valve annulus segment 22 and the main body segment 21, and covers the inner core extending further into the valve annulus segment 22 to form the second rod 42. Thus, the absorbable portion of the absorbable valve stent 100 is partially degradable, and the non-absorbable portion of the absorbable valve stent 100 is completely non-degradable.

[0070] In this embodiment, when the absorbable and non-absorbable parts of the absorbable valve stent 100 are made of two different materials and separately shaped before being assembled by connecting measures, preferably, the main body segment 21 and the valve annulus segment 22 of the outer stent 1 can be connected by the connecting structure 5 and / or welding, or by heat fusion. Welding or heat fusion connection between the main body segment 21 and the valve annulus segment 22 ensures a stable and reliable connection. The connection between the main body segment 21 and the valve annulus segment 22 via the connecting structure 5 has the advantage of simple and convenient assembly.

[0071] A preferred embodiment of the connection structure 5 between the main body segment 21 and the valve annulus segment 22 of the external support 1 is an interference fit connection structure. See also Figure 3 Preferably, a protrusion 51 and a groove 52 are respectively provided on the end faces of the main body segment 21 and the annular segment 22 where they meet. The size of the protrusion 51 can be slightly larger than the size of the groove 52, so that the protrusion 51 and the groove 52 can be interference-fitted, that is, the protrusion 51 is inserted and fixed in the groove 52 by interference fit, thereby realizing the fixed connection between the main body segment 21 and the annular segment 22 by interference fit. In other embodiments, the size of the protrusion 51 can also be slightly smaller than the size of the groove 52, so that the protrusion 51 and the groove 52 can be gap-fitted. After the protrusion 51 is inserted into the groove 52, welding is performed at the joint where the main body segment 21 and the annular segment 22 meet, thereby realizing the fixed connection between the main body segment 21 and the annular segment 22 by the connecting structure 5 and welding.

[0072] Another preferred embodiment of the connection structure 5 between the main body segment 21 and the annular segment 22 of the outer support 1 is a riveted connection structure. See also Figure 4Preferably, a connecting hole 53 is provided at the end where the main body segment 21 and the petiole segment 22 are connected. The connecting holes 53 at the end of the main body segment 21 and the petiole segment 22 are connected and fixed by a rivet 54, thereby realizing the connection and fixation between the main body segment 21 and the petiole segment 22 by the rivet 54.

[0073] The biodegradable absorbent material used in the absorbable valve stent 100 of this embodiment is not limited. Preferably, it can be a polyester biodegradable material such as polylactic acid, polycaprolactone, polyglycolic acid, polyanhydride, polycarbonate, polyurethane, polyphosphate, or polyorthoester. It can also be a biodegradable metallic material such as magnesium-based alloy, zinc-based alloy, or iron-based alloy. The non-biodegradable absorbent material used in the absorbable valve stent 100 of this embodiment is not limited. Preferably, it can be an elastic memory material, such as a nickel-titanium alloy. The forming method of the absorbable and non-absorbable parts of the absorbable valve stent 100 of this embodiment is not limited. Preferably, it can be formed by thermosetting after cutting the tubing, or it can be formed by braiding filaments.

[0074] When the main body segment 21 and the valve annulus segment 22 of the external support 1 are connected by hot melt, a suitable hot melt material must first be selected. If the main body segment 21 is made of polylactic acid (PLA), its melting point is between 150℃ and 180℃. A hot melt adhesive or connecting material with a similar melting point and good biocompatibility should be selected. Before connection, the connection area needs to be cleaned and dried to remove surface impurities and moisture to ensure the quality of the hot melt connection. For example, anhydrous ethanol can be used to wipe and clean the connection area, followed by drying in a vacuum drying oven at 50℃-60℃ for 2 to 4 hours to achieve the optimal connection state for the material surface. A suitable mold can be designed to fix the two ends at the mating point. During the hot melt connection process, the connecting parts are heated to a certain temperature to soften them, and then pressure is applied to join the two ends together. For materials such as PLA and polycaprolactone, the preferred temperature range for hot melt connection is 60℃-120℃, with the specific temperature depending on the specific type and grade of the material. After hot melt connection, a cooling and curing process should be performed to ensure the strength and stability of the connection. The cooling process should be carried out in a controlled environment to avoid excessive shrinkage or deformation of the connection parts.

[0075] In this embodiment of the absorbable valve stent 100, when the first rod 41 constituting the main body segment 21 of the outer stent 2 is made entirely of a biodegradable absorbable material or is made of a non-fully absorbable rod, and when the second rod 42 constituting the valve annulus segment 22, the connecting frame 3, and the inner stent 1 of the outer stent 2 is made of a non-fully absorbable rod, the degradation cycle of the biodegradable absorbable material used is longer than the endothelialization cycle of the valve annulus segment 22 of the outer stent 2. This ensures that after implantation, before the portion of the absorbable valve stent 100 made of the biodegradable absorbable material is completely degraded, the portion made of the non-biodegradable absorbable material has been thoroughly endothelialized. This provides better coverage, fixation, and support for the portion of the absorbable valve stent 100 that remains due to non-biodegradability and absorption, making the design of the absorbable valve stent 100 in this embodiment safe and reliable. After implantation, the endothelialization period of the absorbable valve stent 100 is 1 to 3 months. Preferably, the degradation period of the biodegradable absorbable material used in the absorbable valve stent 100 of this embodiment is more than 6 months, which can ensure that the part made of non-degradable absorbable material has been completely endothelialized before the part of the absorbable valve stent 100 made of biodegradable absorbable material is completely degraded.

[0076] Relatively speaking, biodegradable absorbent materials are slightly weaker in rigidity than non-biodegradable absorbent materials. Therefore, in order to compensate for the insufficient support force of the main body section 21 of the outer support 2 caused by replacing the non-biodegradable absorbent material with a biodegradable absorbent material, it is preferable to increase the width, diameter or wall thickness of the first rod 41 constituting the main body section 21. The width, diameter or wall thickness of the first rod 41 is 1 to 2.5 times larger than the size of the metal support rod commonly used in the prior art.

[0077] For the absorbable portion of the absorbable valve stent 100 in this embodiment, when the first rod 41 is made entirely of a biodegradable absorbable material, such as polylactic acid, considering its degradation characteristics and initial support requirements, the diameter, rod width, or wall thickness of the first rod 41 is preferably between 0.5mm and 2.5mm, for example, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1.0mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm, 2.0mm, 2.1mm, 2.2mm, 2.3mm, 2.4mm, and 2.5mm. When the degradation cycle is set to 8 to 10 months, the first rod 41 made of polylactic acid with a diameter, rod width or wall thickness of 1 mm or more can provide good support stability in the early stage of implantation, and its degradation rate can match the tissue repair process well over time, avoiding premature loss of support.

[0078] For the non-absorbable portion of the absorbable valve stent 100 in this embodiment, when the second rod 42 is entirely made of a non-degradable absorbable material, such as a nickel-titanium shape memory alloy braided wire structure, the diameter, width, or wall thickness of the second rod 42 can be within the range of 0.3mm-1mm. This is because nickel-titanium alloy has good mechanical properties and shape memory characteristics. This range of diameter, width, or wall thickness ensures that sufficient strength and elasticity are maintained during long-term use to support the valve leaflets and resist blood flow impact. In actual product design, fine-tuning can be made according to the specific mitral or tricuspid valve replacement scenario and individual patient differences. For example, for elderly patients or patients with weak cardiac function and relatively small blood flow impact, a thinner diameter, width, or wall thickness of the second rod 42 can be appropriately selected; while for young patients with good physical condition and expected high cardiac load, a diameter, width, or wall thickness close to the upper limit of the second rod 42 can be selected to ensure the durability and stability of the non-absorbable portion of the absorbable valve stent 100.

[0079] It should be noted that, in this article, the diameter of the first member 41 / second member 42 refers to the diameter when the first member 41 / second member 42 is a columnar structure, which can be a cylinder or a prism; the width and wall thickness of the first member 41 / second member 42 refer to the width and thickness when the first member 41 / second member 42 is a flat structure, where the thickness is the radial extension of the cross-section of the first member 41 / second member 42 in the support, and the width is the dimension of the cross-section of the first member 41 / second member 42 in the direction perpendicular to the thickness.

[0080] When both the inner stent 1 and the outer stent 2 adopt a mesh structure, the mesh size can be determined according to the design and functional requirements of the valve prosthesis. The mesh of the inner stent 1 can be smaller to provide sufficient leaflet support; preferably, the mesh size of the inner stent 1 is between 5mm and 10mm. The mesh of the outer stent 2 can be larger to reduce long-term effects on the atrium; preferably, the mesh size of the outer stent is between 5mm and 25mm. For the absorbable portion of the absorbable valve stent 100 in this embodiment, when the first rod 41 is entirely made of a biodegradable absorbable material, its mesh should be denser and smaller to ensure sufficient support. Preferably, the mesh size of the outer stent 2 of the absorbable valve stent 100 in this embodiment is 0.4 to 0.8 times smaller than that of the metal mesh outer stent. More preferably, the mesh size of the main body segment 21 of the outer stent 2, composed of the first rod 41, is between 2mm and 20mm. It should be noted that the grid size refers to the maximum size of a single grid cell in a grid structure. For example, when using a rhombus grid, the length of the longer diagonal of the rhombus is the maximum size of the rhombus grid cell.

[0081] In this embodiment of the absorbable valve stent 100, to compensate for the weakened support force after the main body segment 21 of the external stent 2 is made of a biodegradable absorbable material, preferably, a reinforcing rib structure can be provided on the main body segment 21. More preferably, a reinforcing rib structure is added at the main stress-bearing parts of the main body segment 21, such as the curved area where the main body segment 21 contacts the atrial wall, or at the critical node connecting the main body segment 21 and the valve annulus segment 22. The material of the reinforcing rib structure is preferably the same as that of the main body segment 21, and the cross-sectional shape of the reinforcing rib structure is preferably triangular or rectangular. A preferred embodiment is a triangular cross-section reinforcing rib structure made of polylactic acid, with a height 0.5 to 1 times the diameter, width, or wall thickness of the first member 41 constituting the main body segment 21, and a thickness 0.3 to 0.6 times the diameter, width, or wall thickness of the first member 41. After adding the reinforcing rib structure, the maximum stress of the main body segment 21 of the external stent 2 when subjected to simulated blood flow impact force and cardiac contraction force can be reduced by about 20%-35%, which significantly improves the structural strength and stability of the main body segment 21 of the external stent 2 and effectively reduces the risk of valve prosthesis displacement caused by deformation of the main body segment 21 of the external stent 2.

[0082] In this embodiment of the absorbable valve stent 100, to compensate for the weakening of support after the main body segment 21 of the outer stent 2 is made of a biodegradable absorbable material, preferably, see... Figure 5 A biodegradable stent 6 can be nested within the main body segment 21. Preferably, the biodegradable stent 6 is annular or spherical, has a mesh structure, and is made of biodegradable absorbable material. By adding a nested biodegradable stent 6 inside the main body segment 21 of the outer stent 2, the main body segment 21 of the outer stent 2 can be reinforced. During implantation, the outer stent 2 can be implanted first, and then a biodegradable stent 6 can be implanted in the atrium, nested within the main body segment 21 of the outer stent 2. The biodegradable stent 6 within the main body segment 21 of the outer stent 2 can be arranged directly opposite to the main body segment 21, so that the mesh of the biodegradable stent 6 is directly opposite to the mesh of the main body segment 21; alternatively, the biodegradable stent 6 within the main body segment 21 of the outer stent 2 can be staggered, so that the mesh of the biodegradable stent 6 is staggered from the mesh of the main body segment 21.

[0083] Furthermore, in the absorbable valve stent 100 of this embodiment, the first rod 41 constituting the main body segment 21 may include a rod core and a sheath covering the rod core. The sheath is made of a biodegradable absorbable material, and the rod core is a reinforcing structure to improve the overall support force of the first rod 41. The rod core may be a non-degradable metal memory wire, a biodegradable absorbable alloy material that is harder than the sheath, or other composite materials. The mechanical properties of the rod core are superior to those of the biodegradable absorbable material of the sheath to achieve the purpose of reinforcement, thereby compensating for the problem of weakened support force after the main body segment 21 of the outer stent 2 is made of a biodegradable absorbable material.

[0084] Furthermore, in the absorbable valve stent 100 of this embodiment, when the main body segment 21 is woven into shape using braided yarn, it can be bound and fixed at the braiding nodes with sutures made of biodegradable absorbable material to enhance the supporting force, thereby compensating for the problem of weakened supporting force after the main body segment 21 of the outer stent 2 is made of biodegradable absorbable material.

[0085] In this embodiment of the absorbable valve stent 100, to achieve better fixation and prevent paravalvular leakage, preferably, the annular segment 22 of the outer stent 2 may be provided with a barbed structure. After implantation, the barbed structure can penetrate the tissue near the annulus, providing anchoring force and preventing displacement of the absorbable valve stent 100. Simultaneously, the barbed structure on the annular segment 22 can also compensate for the decrease in support force caused by the use of a biodegradable absorbable material in the main body segment 21 of the outer stent 2. Since the absorbable valve stent 100 in this embodiment mainly relies on the spherical structure of the main body segment 21 of the outer stent 2 located inside the atrium to provide anchoring force, the requirement for support force on the annular segment 22 of the outer stent 2 is reduced. Therefore, a smaller annular segment 22 can be used, provided that the size of the annular contact portion 222 of the annular segment 22 is larger than the size of the annulus, thus avoiding excessive opening of the annulus and reducing the impact on the ventricular outflow tract.

[0086] In this embodiment of the absorbable valve stent 100, the height of the main body segment 21 of the outer stent 2 is preferably 30%-70% of the overall height of the absorbable valve stent 100 along the axial direction of the absorbable valve stent 100. When this proportion is close to 30%, it is suitable for patients with relatively small mitral valve annulus, limited atrial space, and a relatively compact cardiac anatomy. In this case, a lower height of the main body segment 21 of the outer stent 2 can reduce the occupation of the atrial internal space, reduce the impact on the normal physiological function of the atrium, and still provide sufficient anchoring force. For example, in studies on some patients with congenital heart disease, due to the special development of their cardiac structure, a lower proportion of the height of the main body segment 21 of the outer stent 2 is adopted. This design ensures stable fixation of the valve prosthesis while effectively avoiding hemodynamic abnormalities caused by excessive occupation of atrial space by the main body segment 21 of the outer stent 2. When this proportion approaches 70%, it is more suitable for patients with severe mitral regurgitation, significant atrial dilation, or those requiring stronger anchoring force. A larger proportion of the external stent's main body segment 21 height increases the contact area and friction between the external stent's main body segment 21 and the atrial wall, better resisting blood flow impact and the risk of valve stent displacement. In some clinical cases, for patients with significant atrial dilation due to long-term mitral regurgitation, a higher proportion of the external stent's main body segment 21 design significantly improved the stability of the valve prosthesis and effectively improved cardiac function. In practical applications, physicians can accurately assess the patient's specific cardiac anatomy, pathological condition, and hemodynamic parameters using imaging examinations such as echocardiography and CT scans to determine the most suitable proportion of the external stent's main body segment 21 height for the patient.

[0087] In this embodiment, preferably, the shape of the connecting frame 3 is any one or more combinations of arc, S-shape, wave, V-shape, and grid shape. The connecting frame 3 is horizontally, arc-shaped, or inclined between the annular segment 22 and the inner support 1. When the connecting frame 3 is inclined between the annular segment 22 and the inner support 1, the bottom end of the inner support 1 is higher or lower than the bottom end of the annular segment 22 of the outer support 1.

[0088] When the connecting frame 3 is connected upwardly at an angle between the annulus segment 22 and the inner support 1, it can disperse the radial force applied to the outer support 2 by the annulus contraction, thereby reducing the radial pressure on the inner support 1 and maintaining the relative stability of the shape and size of the inner support 1 to maintain a better leaflet closure effect. At the same time, this structure also makes it easier to pull the absorbable valve stent 100 from the top into the sheath of the delivery system.

[0089] When the connecting frame 3 is inclined downwards between the annular segment 22 and the inner stent 1, it can also disperse the radial force applied to the outer stent 2 by the annular contraction, reduce the radial pressure on the bottom end of the inner stent 1, thereby maintaining the relative stability of the shape and size of the inner stent 1 to maintain better leaflet closure effect, and also help with the insertion of the absorbable valve stent 100 into the sheath. Furthermore, the downward-inclined structure of the connecting frame 3 can also maintain the relative stability of the inner stent 1 and prevent axial slippage.

[0090] like Figure 6 As shown, based on the absorbable valve stent 100 of the present invention, this embodiment also provides a valve prosthesis. The valve prosthesis of this embodiment includes the absorbable valve stent 100, leaflets 200, and skirt membrane 300 described above. The leaflets 200 are disposed on the inner stent 1 and are used to replace the original valve. The skirt membrane 300 is disposed on the annular segment 22 of the inner stent 1 and the outer stent 2, serving to seal and promote endothelialization. The skirt membrane 300 attached to the outer stent 2 is disposed on the annular segment 22 of the outer stent 2, such that the junction of the main body segment 21 and the annular segment 22 of the outer stent 2 is higher than the attachment position of the skirt membrane 300 on the outer stent 2. Therefore, the decomposition and absorption of the main body segment 21 will not affect the fixation of the skirt membrane 300 on the outer stent 2.

[0091] Preferably, in the valve prosthesis of this embodiment, the attachment height of the skirt membrane 300 on the annular segment 22 of the outer stent 2 should be such that the skirt membrane 300 is not higher than the pulmonary vein orifice after the valve prosthesis is implanted, so as to avoid affecting the blood flow of the pulmonary vein orifice and prevent blood leakage or thrombosis caused by covering the pulmonary vein orifice.

[0092] Preferably, the valve prosthesis in this embodiment further includes a connector 400, which is disposed on the top of the main body segment 21 of the outer support 2. The first rods 41 on the top of the main body segment 21 are all connected to the connector 400. The connector 400 fixes and constrains the first rods 41 on the top of the main body segment 21, which are in a free state. The connector 400 also has a connecting joint that can be matched with the delivery system for detachably connecting the absorbable valve stent 100 to the delivery system, so as to deliver the valve prosthesis into the human body through the delivery system and realize the implantation, release and withdrawal operations of the valve prosthesis.

[0093] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present invention, and these improvements and substitutions should also be considered within the scope of protection of the present invention.

Claims

1. An absorbable valve stent, comprising: The system includes an inner stent (1) and an outer stent (2) disposed on the outer periphery of the inner stent (1). The outer stent (2) includes a main body segment (21) and a valve annulus segment (22) connected to each other. The main body segment (21) is used to match the atrium, and the valve annulus segment (22) is used to match the valve annulus. The bottom of the valve annulus segment (22) is connected to the bottom of the inner stent (1) through a connecting frame (3). The main body segment (21) is composed of a first rod (41). The first rod (41) is a non-fully absorbable rod or is made entirely of a biodegradable absorbable material. The non-fully absorbable rod includes an inner core made of a non-biodegradable absorbable material and an outer skin made of a biodegradable absorbable material that wraps around the inner core.

2. The absorbable valve stent of claim 1, wherein, The annular segment (22), the connecting frame (3), and the inner support (1) are all composed of a second rod (42), which is either a non-fully absorbable rod or made entirely of a non-degradable absorbable material; preferably, the first rod (41) and the second rod (42) are both non-fully absorbable rods and are made of the same material, and the absorbable valve stent (100) is an integrally formed piece; preferably, the second rod (42) is made entirely of a non-degradable absorbable material, and the diameter, rod width, or wall thickness of the second rod (42) is 0.3mm-1mm.

3. The absorbable valve stent of claim 2, wherein, The degradation cycle of the biodegradable absorbent material is longer than the endothelialization cycle of the annular segment (22); preferably, the degradation cycle of the biodegradable absorbent material is more than 6 months.

4. The absorbable valve stent of claim 1, wherein, The main body segment (21) and the petiole segment (22) are connected by a connecting structure (5) and / or by welding or by hot melting; preferably, the connecting structure (5) is an interference fit connection structure or a rivet connection structure; preferably, a protrusion (51) and a groove (52) are respectively provided on the end faces of the main body segment (21) and the petiole segment (22) that meet, the protrusion (51) and the groove (52) are interference fit, or the protrusion (51) and the groove (52) are gap fit and welded to reinforce the joint where the main body segment (21) and the petiole segment (22) meet.

5. The absorbable valve stent of claim 1, wherein, The biodegradable absorbent material is polylactic acid, polycaprolactone, polyglycolic acid, polyanhydride, polycarbonate, polyurethane, polyphosphate, polyorthoester, magnesium-based alloy, zinc-based alloy, or iron-based alloy.

6. The absorbable valve stent of claim 1, wherein, The first rod (41) has a width, diameter, or wall thickness that is 1 to 2.5 times larger than that of the metal support rod; or, when the first rod (41) is made entirely of a biodegradable absorbent material, the diameter, width, or wall thickness of the first rod (41) is 0.5 mm to 2.5 mm; or, when the first rod (41) is made entirely of a biodegradable absorbent material, and the degradation cycle of the biodegradable absorbent material is 8 to 10 months, the diameter, width, or wall thickness of the first rod (41) is 1 mm or more.

7. The absorbable valve stent of claim 1, wherein, Both the inner support (1) and the outer support (2) adopt a mesh structure. The mesh size of the inner support (1) is 5mm-10mm, and the mesh size of the outer support (2) is reduced by 0.4 to 0.8 times compared with the size of the metal mesh outer support. Preferably, the mesh size of the main body segment (21) of the outer support (2) is 2mm-20mm.

8. The absorbable valve stent of claim 1, wherein, Adopt any one or a combination of the following reinforcement measures: Strengthening Measure 1: The main body segment (21) is provided with a reinforcing rib structure; preferably, the reinforcing rib structure is added in the bending area of ​​the main body segment (21) or at the key node connecting the main body segment (21) and the valve annulus segment (22); preferably, the cross-sectional shape of the reinforcing rib structure is triangular or rectangular; preferably, the first rod (41) is made of biodegradable absorbable material, the cross-sectional shape of the reinforcing rib structure is triangular, the height of the reinforcing rib structure is 0.5 to 1 times the diameter, rod width or wall thickness of the first rod (41), the thickness of the reinforcing rib structure is 0.3 to 0.6 times the diameter, rod width or wall thickness of the first rod (41), and the maximum stress of the main body segment (21) when subjected to simulated blood flow impact force and cardiac contraction force is reduced by 20%-35%; Strengthening Measure 2: A biodegradable support (6) is nested inside the main body segment (21); preferably, the biodegradable support (6) is a ring-shaped or spherical mesh structure; preferably, the biodegradable support (6) is arranged opposite to or staggered from the main body segment (21); Strengthening Measure 3: The first rod (41) includes a rod core and a rod skin that wraps around the rod core. The rod skin is made of a biodegradable absorbent material, and the rod core is made of a non-biodegradable metal memory wire or a biodegradable absorbent alloy material or composite material that is harder than the rod skin. Fourthly, the main body segment (21) is woven with braided yarn and bound and fixed at the braided nodes with biodegradable and absorbable stitching. Fifthly, the annular segment (22) is provided with a barb structure.

9. The absorbable valve stent of claim 1, wherein, Along the axial direction of the absorbable valve stent (100), the height of the main body segment (21) accounts for 30%-70% of the overall height of the absorbable valve stent (100).

10. A valve prosthesis, characterized in that, Includes an absorbable valve stent (100), leaflets (200) and a skirt membrane (300) as described in any one of claims 1 to 9, wherein the leaflets (200) are disposed on the inner stent (1) and the skirt membrane (300) is disposed on the annular segment (22) of the inner stent (1) and the outer stent (2).

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