Anti-displacement artificial heart valve stent

Abstract

The invention discloses an anti-displacement artificial heart valve stent, and relates to the technical field of valve stents.The anti-displacement artificial heart valve stent comprises a stent body which is of a net-tube-shaped structure and comprises an inflow section, a transition section and an outflow section which are sequentially arranged in the axial direction, and a valve blade is arranged in the transition section; the end, away from the transition section, of the inflow section is an inflow end for blood inflow, and the end, away from the transition section, of the outflow section is an outflow end for blood outflow. In a natural state, the inflow end and the outflow end are gradually expanded outwards in the direction away from the transition section; the auxetic section is arranged between the transition section and the outflow section in the axis direction of the stent body; the auxetic section is of a geometrical structure with the negative Poisson's ratio characteristic, and when the auxetic section is subjected to axial impact force of blood, the auxetic section deforms to convert axial stretching displacement into radial expansion displacement. According to the present invention, the anti-displacement performance is excellent, the blood vessel is not damaged, and the long-term stability and reliability are provided.

Description

Technical Field

[0001] This invention relates to the field of valve stent technology, and in particular to an anti-displacement artificial heart valve stent. Background Technology

[0002] Heart valves are crucial structures between the atria and ventricles, and between the ventricles and arteries. Their core function is to prevent blood backflow and ensure that blood flows in the direction of atrium → ventricle → aorta / pulmonary artery. Severe valvular disease can directly lead to patient death. Clinically, the main treatment for heart valve disease is surgical or interventional replacement with artificial heart valves.

[0003] In transcatheter aortic valve implantation (TAVA), valve displacement is a serious intraoperative complication. It can occur during implantation, and in rare cases, it can be delayed. Displacement primarily manifests as embolism into the aorta or migration into the left ventricle. Currently, the industry's design approaches to improve the anti-displacement performance of artificial heart valve stents mainly fall into three categories: 1. Add anchoring devices: such as foldable positioning components, valve seats, fixing ears, barbs, suction cups, etc., but these anchoring devices are mostly independent structures on the stent, which can easily cause vascular damage; 2. Increase positive pressure: Select a stent with a diameter larger than the blood vessel to increase positive pressure, but excessive vascular pressure can damage the blood vessel wall; 3. Optimize stent shape or contact area: Make the stent profile streamlined to reduce hemodynamics, or increase the contact area between the stent and the blood vessel to improve the friction coefficient, but these two methods are difficult to guarantee the long-term stability of the stent.

[0004] Therefore, how to effectively address the displacement of interventional prosthetic valves remains an important issue in this field. Summary of the Invention

[0005] The purpose of this invention is to provide an anti-displacement artificial heart valve stent to solve the problems existing in the prior art, so as to achieve excellent anti-displacement performance, not damage blood vessels, and have long-term stability and reliability.

[0006] To achieve the above objectives, the present invention provides the following solution: This invention provides an anti-displacement artificial heart valve stent, comprising: a stent body, which is a mesh-like structure including an inflow section, a transition section, and an outflow section arranged sequentially along its axial direction; the transition section is used to house valve leaflets; the end of the inflow section away from the transition section is an inflow end for blood inflow, and the end of the outflow section away from the transition section is an outflow end for blood outflow; in its natural state, both the inflow end and the outflow end gradually expand outward in the direction away from the transition section; a stretching section, which is disposed between the transition section and the outflow section in the axial direction of the stent body; the stretching section has a geometric configuration with negative Poisson's law, and when the stretching section is subjected to the axial impact force of blood, the stretching section deforms to convert the axial tensile displacement into radial expansion displacement.

[0007] Preferably, the expansion section includes multiple expansion units distributed circumferentially along the axis of the support body; each expansion unit includes an upper expansion structure and a lower expansion structure arranged along the axial direction of the support body, the upper expansion structure and the lower expansion structure being connected by a connecting line group; the upper expansion structure has a first upper protrusion, a first upper concave portion and a second upper protrusion arranged sequentially along the circumference of the support body; the lower expansion structure has a first lower protrusion, a first lower concave portion and a second lower protrusion arranged sequentially along the circumference of the support body; the first upper protrusion corresponds to the first lower protrusion, the first upper concave portion corresponds to the first lower concave portion, and the second upper protrusion corresponds to the second lower protrusion; in the axial direction of the support body... The distance between the first upper protrusion and the first lower protrusion is a first distance, the distance between the first upper concave portion and the first lower concave portion is a second distance, and the distance between the second upper protrusion and the second lower protrusion is a third distance. The second distance is less than the first distance and the third distance. The first upper protrusion and the first upper concave portion, the first upper concave portion and the second upper protrusion, the first lower protrusion and the first lower concave portion, and the first lower concave portion and the second lower protrusion are all connected by connecting rods. The first upper concave portion is connected to the grid node of the outflow section through the first conductive portion, and the first lower concave portion is connected to the grid node of the transition section through the second conductive portion.

[0008] Preferably, both the inflow section and the outflow section are formed by multiple first V-shaped structures distributed circumferentially along the axis of the support body. The tips of the first V-shaped structures are all located at the end away from the transition section. The corresponding ends of two adjacent first V-shaped structures are connected to form a grid node for connecting the first conductive part. The transition section includes a first rhombus unit and a second rhombus unit. The first rhombus unit includes at least one rhombus segment. Each rhombus segment is distributed and connected sequentially along the axis of the support body. Each rhombus segment includes multiple complete rhombus frames distributed circumferentially around the axis of the support body and connected to each other. The vertices of each complete rhombus frame near the outflow section form a grid node for connecting the second conductive part. The second rhombus unit is formed by multiple second V-shaped structures distributed circumferentially around the axis of the support body. The second V-shaped structure corresponds one-to-one with the complete rhombus frame. The tip of the second V-shaped structure is connected to the bottom point of the complete rhombus frame of the first rhombus unit near the inflow section. The ends of two adjacent second V-shaped structures are connected to form a bottom grid node. The ends of each first V-shaped structure in the inflow section are respectively connected to the corresponding bottom grid node.

[0009] Preferably, the expansion unit is a hexagonal concave structure, in which two opposite vertices are close to each other and respectively form the first upper concave portion and the first lower concave portion; in the hexagonal concave structure, two vertices connected to the first upper concave portion respectively form the first upper convex point and the second upper convex point; two vertices connected to the first lower concave portion respectively form the first lower convex point and the second lower convex point; in the hexagonal concave structure, the line connecting the first upper convex point and the first lower convex point and the line connecting the second upper convex point and the second lower convex point together form the connecting line group; and adjacent two hexagonal concave structures share the same connecting line.

[0010] Preferably, the expansion unit includes a hexagonal frame, an upper curve, and a lower curve; the upper curve and the lower curve are symmetrically distributed vertically and fixed to the hexagonal frame; the lower curve is shaped like a "Z", with the middle part of the "Z" shape located inside the hexagonal frame and forming corresponding first upper concave portion and first lower concave portion; the two ends of the upper curve respectively form a first upper convex point and a second upper convex point, and the two ends of the lower curve respectively form a first lower convex point and a second lower convex point; the upper vertex of the hexagonal frame forms the first conductive portion, and the lower vertex of the hexagonal frame forms the second conductive portion.

[0011] Preferably, the inflow section, the transition section, the expansion section, and the outflow section are integrally formed.

[0012] Preferably, the Poisson's ratio v of the stretching section varies in the range of -1 ≤ v < 0.

[0013] Preferably, the ratio of the axial length of the inflow section to the transition section and the ratio of the axial length of the outflow section to the transition section are both 1:(4.5~6); the ratio of the axial length of the expansion section to the transition section is 1:(2~3); the axial length of the support body is 35mm~39mm; and the diameter of the opening of the inflow end and the outflow end is both 17.5mm~32.5mm.

[0014] Preferably, the transition section is flared at one end near the inflow section and connects with the expansion structure of the inflow section; the stretching section is flared at one end near the outflow section and connects with the expansion structure of the outflow section.

[0015] Preferably, the support body is made of shape memory alloy material.

[0016] The present invention achieves the following technical effects compared to the prior art: The anti-displacement artificial heart valve stent provided by this invention, through the coordinated design of the stent body and the expansion segment, allows the inflow and outflow ends to expand outwards away from the transition segment under natural conditions. This eliminates the need for a large-sized stent to increase positive pressure, as the flared structure enhances contact with the vessel wall, preventing excessive pressure damage. Simultaneously, a expansion segment with negative Poisson's ratio is provided between the transition and outflow segments. When this expansion segment is subjected to axial impact force from blood flow—that is, when the heart valve stent is closed and blood flow impacts the artificial valve from top to bottom—the blood generates an axial impact force on the artificial valve. The expansion segment design of the stent body allows it to convert this impact force into axial tension, thereby triggering radial expansion. This expansion can... The deformation of its own geometric configuration transforms axial tensile displacement into radial expansion displacement, further increasing the contact area and tightness between the outflow section and the vessel wall as the stretching section expands radially. This achieves dynamic and active anti-displacement under blood flow impact. Compared to passive methods that simply optimize stent morphology or contact area, this design relies on blood flow impact to form an adaptive anti-displacement effect, allowing the stent's anti-displacement performance to continue to play a role with physiological blood flow impact, significantly improving the long-term stability of stent anti-displacement. Furthermore, the stent body has a mesh-like structure, with the transition section used to house valve leaflets. The overall structural design is adapted to the clinical implantation and use requirements of artificial heart valves, achieving excellent anti-displacement effects while ensuring normal valve support and smooth blood flow. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 A schematic diagram of the overall structure of the anti-displacement artificial heart valve stent provided by the present invention; Figure 2 A schematic diagram of the first type of tensile segment of the anti-displacement artificial heart valve stent provided by the present invention; Figure 3 The schematic diagram of a half-integral structure of the first type of tensile segment of the anti-displacement artificial heart valve stent provided by the present invention is shown. Figure 4 A partial structural diagram of the first type of tensile segment of the anti-displacement artificial heart valve stent provided by the present invention; Figure 5 The schematic diagram of a semi-integral structure of the second type of tensile segment of the anti-displacement artificial heart valve stent provided by the present invention is shown. Figure 6 The diagram shows a partial structural representation of the second type of tensile segment of the anti-displacement artificial heart valve stent provided by the present invention.

[0019] In the picture: 1-Inflow section; 11-First V-shaped structure; 2-Transition section; 21-Complete rhombus frame; 22-Second V-shaped structure; 23-Bottom grid node; 3-Tension section; 31-First upper concave portion; 32-First upper convex point; 33-Second upper convex point; 34-First lower concave portion; 35-First lower convex point; 36-Second lower convex point; 37-Connecting rod; 38-First conductive part; 39-Second conductive part; 4-outflow section; 5- Hexagonal concave structure; 6 - Hexagonal frame; 61 - Upper curve; 62 - Lower curve. Detailed Implementation

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

[0021] The purpose of this invention is to provide an anti-displacement artificial heart valve stent to solve the problems existing in the prior art, so as to achieve excellent anti-displacement performance, not damage blood vessels, and have long-term stability and reliability.

[0022] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0023] Example 1 This embodiment provides an anti-displacement artificial heart valve stent, such as... Figures 1-6 As shown, it includes: The scaffold body is a tubular structure (such as...) Figure 2 and Figure 5 As shown, the entire stent body is mesh-like and annular, including an inflow section 1, a transition section 2, and an outflow section 4 arranged sequentially along its axial direction. The transition section 2 is used to house the valve leaflets. The end of the inflow section 1 away from the transition section 2 is the inflow end for blood inflow, and the end of the outflow section 4 away from the transition section 2 is the outflow end for blood outflow. In its natural state, both the inflow and outflow ends gradually expand outwards in the direction away from the transition section 2 (their ends expand outwards to the maximum diameter to form support, the contour of the maximum diameter being slightly larger than the diameter of the transition section 2, providing radial support force by contacting the vessel wall at the outwardly expanded end nodes, preventing the valve stent from shifting). Therefore, the outflow and inflow sections as a whole present a structure similar to "petals," as... Figure 2 (as shown) The expansion section 3 is located between the transition section 2 and the outflow section 4 in the axial direction of the stent body. The expansion section 3 has a geometric configuration with negative Poisson's law. When the expansion section 3 is subjected to the axial impact force of blood, the expansion section 3 deforms to convert the axial tensile displacement into radial expansion displacement.

[0024] Through the coordinated design of the stent body and the expansion segment 3, the inflow and outflow ends naturally expand outwards away from the transition segment 2. This eliminates the need for a large-sized stent to increase positive pressure, as the flared structure enhances contact with the vessel wall, preventing excessive pressure damage. Simultaneously, a expansion segment 3 with negative Poisson's ratio is positioned between the transition segment 2 and the outflow segment 4. When this expansion segment 3 is subjected to axial impact force from blood flow—that is, when the heart valve stent is closed and blood flow impacts the artificial valve from top to bottom—the blood generates an axial impact force on the artificial valve. The design of the expansion segment 3 in the stent body allows it to convert this impact force into axial tension, triggering radial expansion. This expansion is achieved through its geometric configuration. The axial tensile displacement is transformed into radial expansion displacement, which further increases the contact area and tightness between the outflow section 4 and the blood vessel wall as the expansion section 3 expands radially. This achieves dynamic and active anti-displacement under blood flow impact. Compared with passive methods that simply optimize the stent shape or contact area, this design relies on the blood flow impact force to form an adaptive anti-displacement effect, allowing the stent's anti-displacement performance to continue to play a role with the physiological blood flow impact, greatly improving the long-term stability of the stent's anti-displacement. Moreover, the stent body is a mesh-like structure, and the transition section 2 is used to set the valve leaflets. The overall structural design is adapted to the clinical implantation and use requirements of artificial heart valves, achieving excellent anti-displacement effect while taking into account the normal bearing capacity of the valve and the smooth flow of blood.

[0025] Specifically, utilizing the negative Poisson's ratio effect of the expansion segment 3, through the synergistic coordination of mechanical design and Poisson's ratio range, when the heart valve stent impacts the artificial valve from top to bottom during valve closure, the expansion segment 3 experiences radial displacement under axial force. The outflow end of the stent body expands radially under the traction of the expansion segment 3, thereby improving the stent's anti-migration performance. This active radial expansion response enhances the contact area and tightness between the stent body and surrounding tissues, effectively improving the stent's anti-migration performance. Specifically, when the heart valve closes at the end of systole, the blood exerts a downward impact force on the artificial valve. At this time, the design of the expansion segment 3 allows it to convert this impact force into its own axial tension, thereby triggering radial expansion. This expansion not only improves the contact between the stent body and the valve annulus but also effectively reduces the risk of valve leakage. It also enhances the stability of the stent body within the valve annulus, reducing the possibility of stent displacement due to changes in physiological load.

[0026] Specifically, by precisely controlling the mechanical properties of the tensile segment 3, the stent body can maintain a stable radial force under long-term blood flow impact, avoiding performance degradation due to material fatigue. Therefore, the stent in this embodiment not only provides excellent anti-migration performance in the short term, but also has long-term stability and reliability, providing patients with a safer and more effective treatment option, reducing the risks of reoperation and death, and better meeting actual clinical needs.

[0027] Regarding the explanation of stretching segment 3: In the optional schemes of this embodiment, it is more preferred that the Poisson's ratio v of the stretching segment 3 varies in the range of -1≤v<0.

[0028] Among the optional solutions in this embodiment, the more preferred one is as follows: Figures 1-6 As shown, the expansion section 3 includes multiple expansion units distributed circumferentially along the axis of the support body; each expansion unit includes an upper expansion structure and a lower expansion structure arranged along the axial direction of the support body, and the upper and lower expansion structures are connected by a connecting line group; the upper expansion structure has a first upper protrusion 32, a first upper concave portion 31 and a second upper protrusion 33 arranged sequentially along the circumference of the support body; the lower expansion structure has a first lower protrusion 35, a first lower concave portion 34 and a second lower protrusion 36 arranged sequentially along the circumference of the support body; the first upper protrusion 32 corresponds to the first lower protrusion 35, the first upper concave portion 31 corresponds to the first lower concave portion 34, and the second upper protrusion 33 corresponds to the second lower protrusion 36; in the axial direction of the support body, the first upper... The distance between the side protrusion 32 and the first lower side protrusion 35 is the first distance, the distance between the first upper concave portion 31 and the first lower concave portion 34 is the second distance, and the distance between the second upper side protrusion 33 and the second lower side protrusion 36 is the third distance. The second distance is less than the first distance and the third distance. The first upper side protrusion 32 and the first upper concave portion 31, the first upper concave portion 31 and the second upper side protrusion 33, the first lower side protrusion 35 and the first lower concave portion 34, and the first lower concave portion 34 and the second lower side protrusion 36 are all connected by connecting rods 37. The first upper concave portion 31 is connected to the grid node of the outflow section 4 through the first conductive portion 38, and the first lower concave portion 34 is connected to the grid node of the transition section 2 through the second conductive portion 39.

[0029] Specifically, the following provides structural descriptions of two types of expansion segment 3: The first option: Among the optional solutions in this embodiment, the more preferred one is, such as Figures 2-4As shown, the auxetic unit is a hexagonal concave structure 5. In the hexagonal concave structure 5, the two vertices opposite to each other vertically are close to each other and respectively form a first upper concave part 31 and a first lower concave part 34. In the hexagonal concave structure 5, the two vertices connected to the first upper concave part 31 respectively form a first upper side convex point 32 and a second upper side convex point 33; the two vertices connected to the first lower concave part 34 respectively form a first lower side convex point 35 and a second lower side convex point 36. In the hexagonal concave structure 5, the connection line between the first upper side convex point 32 and the first lower side convex point 35 and the connection line between the second upper side convex point 33 and the second lower side convex point 36 together form a connection line group; and the same connection line is shared between two adjacent hexagonal concave structures 5 (that is, the adjacent sides of two adjacent hexagonal concave structures 5 are shared, or the two adjacent sides are integrated).

[0030] Second: In the alternative solution of this embodiment, preferably, as Figure 5 and Figure 6 shown, the auxetic unit includes a hexagonal frame 6, an upper curve 61 and a lower curve 62; the upper curve 61 and the lower curve 62 are symmetrically distributed vertically and fixed on the hexagonal frame 6. The lower curve 62 is in a U-shape, and the middle part of the U-shape is inside the hexagonal frame 6 (the two ends of the U-shape are integrally formed with the two sides on both sides of the upper vertex of the hexagonal frame 6 and extend outside the hexagonal frame 6, specifically as Figure 5 and Figure 6 shown) and form corresponding first upper concave part 31 and first lower concave part 34; the two ends of the upper curve 61 respectively form a first upper side convex point 32 and a second upper side convex point 33, and the two ends of the lower curve 62 respectively form a first lower side convex point 35 and a second lower side convex point 36; the upper vertex of the hexagonal frame 6 forms a first conduction part 38 (specifically, the upper vertex of the hexagonal frame 6 and part of the side lines on both sides of the upper vertex together form the first conduction part 38), and the lower vertex of the hexagonal frame 6 forms a second conduction part 39 (specifically, the lower vertex of the hexagonal frame 6 and part of the side lines on both sides of the lower vertex together form the second conduction part 39).

[0031] Specifically, the principle explanations of the two structures are as follows: Explanation of the first deformation principle: When the blood flow impacts the valve downward, a downward axial tensile load is generated. This load acts on the first lower concave part 34 and the first upper concave part 31 of the hexagonal concave structure 5 as a concentrated force through the second conduction part 39 and the first conduction part 38. Since this structure has a negative Poisson's ratio configuration, the axial tensile stress forces the concave nodes to be stressed and turn and expand outward; to coordinate the elongation deformation along the axis, the lateral first upper side convex point 32, the second upper side convex point 33 and the corresponding lower side convex points are forced to displace outward, resulting in significant expansion of the unit in the circumferential (radial) direction. This circumferential strain directly pulls the first V-shaped structure 11 of the outflow segment 4 connected to it to expand outward, realizing the expansion of the radial diameter of the stent.

[0032] The second deformation principle is described as follows: The axial tensile load acts on the upper and lower vertices of the hexagonal frame 6 through the conduction part. In the initial state of the auxetic unit, its upper curve 61 and lower curve 62 are bent and contracted with a high curvature in a "Ji" shape; when axial tension is applied, the load is distributed to the curve networks on both sides, forcing the curve structure at the notch of the "Ji" shape to bend and deform to release longitudinal strain, manifested as an increase in the radius of curvature and the arc tending to be flat (i.e., the diastolic effect). The stretching deformation of this curve is necessarily accompanied by an increase in the transverse span, and at the same time drives the side edges of the centrally connected hexagonal frame 6 to synchronously undergo transverse displacement. Thus, the continuous array of curve networks generates cumulative transverse expansion displacement when axially tensioned, driving the outflow section 4 to produce a coordinated radial expansion.

[0033] Specifically, the effects of the two structures are described as follows: The effect of the first structure: The auxetic unit adopts a hexagonal concave structure 5, and its negative Poisson's ratio effect mainly stems from the bending deformation at the endpoints of the connecting rod 37 and the articulated expansion of the concave part under the action of the axial load. When the heart valve closes and withstands the impact of the downward blood flow, the auxetic section 3 is subjected to an axial tensile load, which causes the connecting rod 37 arranged obliquely inside the hexagonal concave structure 5 to deflect towards the tensile axis direction, forcing the included angle of the concave part to increase, and simultaneously driving the outer convex points to produce continuous transverse displacement. This linked deformation of geometric topology has an adaptive mechanical response characteristic, which can smoothly and directly convert the axial strain brought by the blood flow impact into circumferential (radial) expansion strain. Through this mechanism, the auxetic section 3 drives the outflow section 4 to produce a radial expansion that is positively correlated with the axial impact force, dynamically increasing the contact area between the stent body and the blood vessel wall and the radial support stiffness, thereby achieving the anti-displacement anchoring effect of adaptive adjustment with physiological load; in addition, the polygonal topological boundary composed of multiple straight connecting rods 37 has excellent trajectory following performance in laser cutting processing, which is beneficial to ensuring the processing accuracy and dimensional consistency of the nickel-titanium shape memory alloy tube.

[0034] The effect of the second structure: By introducing the continuous and smooth upper curve 61 and lower curve 62, this structure effectively eliminates the local stress concentration effect. Under the action of the physiological load of blood flow impact, this flexible curve configuration can significantly homogenize the stress field distribution, reduce the risk of fretting fatigue and fatigue fracture of the shape memory alloy material under repeated large strains, thereby ensuring the mechanical stability and service life of the artificial valve stent in the long-term implantation environment; at the same time, the circumferential stretching of the curve network is coupled with the linked deformation of the hexagonal frame 6, and can output a more powerful radial support stiffness compared with a single concave structure. And this support force is more continuous and uniform along the circumferential direction of the stent, dynamically enhancing the tissue fit between the outflow end of the stent and the blood vessel wall, and then establishing a more stable and lasting anti-displacement friction interface.

[0035] Among them, the relevant descriptions of the inflow section 1 and the outflow section 4 are as follows: Specifically, the inflow and outflow ends are shaped like a flower crown.

[0036] Specifically, the tips of the first V-shaped structure 11 at the inflow and outflow ends, which are far from the transition section 2, are located on the same circumference, respectively.

[0037] Among the optional solutions in this embodiment, the more preferred one is as follows: Figures 1-3 and Figure 5 As shown, both the inflow section 1 and the outflow section 4 are formed by multiple first V-shaped structures 11 distributed circumferentially along the axis of the support body. The tips (i.e., apexes) of the first V-shaped structures 11 are located at the ends away from the transition section 2. The corresponding ends of two adjacent first V-shaped structures 11 are connected together to form a grid node for connecting the first conductive part 38. The transition section 2 includes a first rhombic unit and a second rhombic unit (the transition section 2 is composed of rhombic structures of the same shape and size to meet the compressibility requirements). The first rhombic unit includes at least one rhombic segment. Each rhombic segment is distributed and connected sequentially along the axis of the support body. The rhombic segment includes multiple complete rhombic frames 21 distributed circumferentially around the axis of the support body and connected to each other (the specific number can be reasonably set according to actual needs). (e.g., 9); the vertices of each complete rhombus frame 21 near the outflow section 4 form grid nodes for connecting the second conduction section 39; the second rhombus unit is formed by multiple second V-shaped structures 22 distributed circumferentially around the axis of the support body, the second V-shaped structure 22 corresponds one-to-one with the complete rhombus frame 21, the tip of the second V-shaped structure 22 is connected to the bottom point of the complete rhombus frame 21 of the first rhombus unit near the inflow section 1, the ends of two adjacent second V-shaped structures 22 are connected to form a bottom grid node 23, the ends of each first V-shaped structure 11 of the inflow section 1 are respectively connected to the corresponding bottom grid node 23 (the first V-shaped structure 11 of the inflow section 1 and the second V-shaped structure 22 of the second rhombus unit can together form a complete rhombus frame structure, such as Figure 1 (As shown).

[0038] Specifically, transcatheter surgery requires compressing the stent body into a very small diameter (e.g., 8mm). Both the inflow and outflow ends adopt a V-shaped structure, which has a small surface area and serves as an open semi-rhomboid boundary. This reduces the likelihood of interference or twisting deformation between the grid units when the stent body is compressed and folded. This not only facilitates the smooth compression of the stent body into the delivery system but also avoids damage to the artificial valve leaflets sutured inside the stent body during compression.

[0039] Regarding the relevant explanations for transition section 2: Specifically, the structure of transition segment 2 is relatively stable, and the artificial heart valve is sutured at this location. This is existing technology and will not be elaborated further.

[0040] Among the optional solutions in this embodiment, the more preferred one is as follows: Figure 1As shown, the ratio of the axial length of the inflow section 1 to the transition section 2 and the ratio of the axial length of the outflow section 4 to the transition section 2 are both 1:(4.5~6); the ratio of the axial length of the expansion section 3 to the transition section 2 is 1:(2~3); the axial length of the support body is 35mm~39mm; and the diameter of the opening at the inflow end and the outflow end is 17.5mm~32.5mm.

[0041] Specifically, a series of products with different opening diameters can be set up. The series diameters can be selected as 18±0.5mm, 20±0.5mm, 22±0.5mm, 24±0.5mm, 26±0.5mm, 28±0.5mm, 30±0.5mm, and 32±0.5mm. The diameter of the transition section 2 is smaller than the diameter of the opening at the inflow and outflow ends. The specific size selection is determined by the size of the implantation site.

[0042] Among the optional solutions in this embodiment, the more preferred one is as follows: Figures 1-3 and Figure 5 As shown, the transition section 2 is flared at the end near the inflow section 1 and is connected to the expansion structure of the inflow section 1; the expansion section 3 is flared at the end near the outflow section 4 and is connected to the expansion structure of the outflow section 4.

[0043] Regarding other related settings: In the optional solutions of this embodiment, it is more preferred that the inflow section 1, the transition section 2, the stretching section 3 and the outflow section 4 are integrally formed.

[0044] Specifically, each part of the support body is composed of multiple repeating units arranged circumferentially.

[0045] In the optional embodiments of this example, a preferred option is that the scaffold body is made of shape memory alloy material, which has good biostability.

[0046] Specifically, in the design of the anti-migrating artificial heart valve stent in this embodiment, a heart valve stent model with a tensile structure (i.e., tensile segment 3) is designed using 3D modeling software. This structure can adjust the shape and size of the unit to meet the needs of patients of different ages. Then, numerical simulation analysis is performed on the basic unit. The established 3D model of the heart valve stent is imported into the finite element analysis software, and material properties are assigned, analysis steps are set, boundary conditions are applied, and meshes are generated before mechanical performance analysis is performed to obtain an anti-migrating heart valve stent with adjustable Poisson's ratio.

[0047] Specifically, a stent model with a tensile structure is designed using 3D modeling software. This structure allows for the adjustment of the shape and size of the units (i.e., individual units distributed in a circumferential array) to meet the needs of patients of different ages. In this embodiment, the basic unit of the stent structure consists of a rhomboid structure and a tensile structure. The size of each stent unit is determined according to the size of the patient's ventricular outflow tract. At the same time, through numerical simulation analysis of the basic unit, a stent configuration with good anti-displacement performance is obtained.

[0048] Specifically, in this embodiment, the anti-displacement artificial heart valve stent can be used by suturing the valve to the transition section 2 of the stent body before surgical implantation, or the stent can be placed in advance before implanting the artificial heart valve to provide a landing point for the valve.

[0049] Specifically, regarding the effectiveness verification of the anti-displacement artificial heart valve stent of this embodiment: To demonstrate the anti-displacement effect of the artificial heart valve stent with the expansion structure in this embodiment, a finite element simulation experiment was conducted to test the anti-displacement performance of this embodiment and the comparative example. The stent in the comparative example uses a full rhomboid unit structure stent of the same size without the expansion structure (i.e., the structure is the same except for the expansion segment 3).

[0050] The software Abaqus was used for simulation. The blood flow impact force was simulated by applying axial displacement to the middle of the valve stent. The stent in Example 1 and Example 2 was subjected to tensile simulation. The specific method is as follows: select nodes in a specific part of the middle of the valve stent and apply axial displacement constraints. Select multiple nodes at the outflow end of the valve stent and apply fixed constraints to limit its axial displacement, so that the valve stent as a whole is stretched.

[0051] Experimental results show that the Poisson's ratio of the stretchable stents in Examples 1 and 2 ranges from 0 to -0.1. Simulation results demonstrate that the stretchable structure proposed in this embodiment achieves the expected effect in artificial heart valve stents. When the valve stent is subjected to axial tension under force, the diameter of the outflow end of the stent in this embodiment gradually increases, thereby increasing the contact area between the valve stent and the implantation site, and thus improving the anti-displacement performance of the valve stent. The Poisson's ratio of the non-stretchable structure stent in the comparative example ranges from 0 to 1.8.

[0052] The axial contact force between the stent and the blood vessel reflects the migration force between the valve stent and the blood vessel. This experimental case simulates the axial contact between the valve stent and the blood vessel under multiple case conditions. The axial contact force at the interface between the blood vessel and the valve stent during the migration process is extracted in the Abaqus post-processing module. The axial displacement range of the stent during the migration process is set to 0-4 mm.

[0053] The average axial contact forces of the valve stents in Examples 1 and 2 and the stents in the comparative example in different cases are shown below:

[0054] Experimental results show that the average movement resistance between the stent with the expansion segment 3 and the blood vessel in this embodiment is greater than that between the non-expansion stent and the blood vessel. The anti-displacement performance of the expansion stent in this embodiment is higher than that of the non-expansion stent.

[0055] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A displacement-resistant artificial heart valve stent, characterized in that: include: The stent body has a mesh-like structure, including an inflow section, a transition section, and an outflow section arranged sequentially along its axial direction. The transition section is used to house valve leaflets. The end of the inflow section away from the transition section is the inflow end for blood inflow, and the end of the outflow section away from the transition section is the outflow end for blood outflow. In its natural state, both the inflow end and the outflow end gradually expand outward in the direction away from the transition section. The expansion section is disposed between the transition section and the outflow section in the axial direction of the stent body; the expansion section has a geometric configuration with negative Poisson bit properties, and when the expansion section is subjected to the axial impact force of blood, the expansion section deforms to convert the axial tensile displacement into radial expansion displacement.

2. The anti-displacement artificial heart valve stent according to claim 1, characterized in that: The expansion section includes multiple expansion units distributed circumferentially along the axis of the support body; each expansion unit includes an upper expansion structure and a lower expansion structure arranged along the axis of the support body, and the upper expansion structure and the lower expansion structure are connected by a connecting line group. The upper expansion structure has a first upper protrusion, a first upper concave portion, and a second upper protrusion arranged sequentially along the circumference of the support body; the lower expansion structure has a first lower protrusion, a first lower concave portion, and a second lower protrusion arranged sequentially along the circumference of the support body; the first upper protrusion corresponds to the first lower protrusion, the first upper concave portion corresponds to the first lower concave portion, and the second upper protrusion corresponds to the second lower protrusion; In the axial direction of the bracket body, the distance between the first upper protrusion and the first lower protrusion is the first distance, the distance between the first upper concave portion and the first lower concave portion is the second distance, and the distance between the second upper protrusion and the second lower protrusion is the third distance. The second distance is less than the first distance and the third distance. The first upper protrusion and the first upper concave portion, the first upper concave portion and the second upper protrusion, the first lower protrusion and the first lower concave portion, and the first lower concave portion and the second lower protrusion are all connected by connecting rods. The first upper concave portion is connected to the grid node of the outflow section through the first conductive portion, and the first lower concave portion is connected to the grid node of the transition section through the second conductive portion.

3. The anti-displacement artificial heart valve stent according to claim 2, characterized in that: Both the inflow section and the outflow section are formed by multiple first V-shaped structures distributed circumferentially along the axis of the support body. The tips of the first V-shaped structures are all located at the end away from the transition section. The corresponding ends of two adjacent first V-shaped structures are connected together to form a grid node for connecting the first conductive part. The transition section includes a first rhombic unit and a second rhombic unit; The first rhomboid unit includes at least one rhomboid segment, and each rhomboid segment is distributed and connected sequentially along the axial direction of the support body. Each rhomboid segment includes a plurality of complete rhomboid frames distributed circumferentially around the axis of the support body and connected to each other. The vertices of each complete rhomboid frame near the outflow section form grid nodes for connecting the second conductive part. The second diamond unit is formed by circumferentially distributing a plurality of second V-shaped structures around the axis of the bracket body. The second V-shaped structures correspond to the complete diamond frames one by one. The tip of the second V-shaped structure is connected to the bottom point of the complete diamond frame of the first diamond unit close to the inflow section. The ends of adjacent two second V-shaped structures are connected to form bottom grid nodes, and the end parts of the first V-shaped structures in the inflow section are respectively connected to the corresponding bottom grid nodes.

4. The anti-displacement artificial heart valve stent according to claim 2, characterized in that: The expansion unit is a hexagonal concave structure, and the two vertices opposite to each other up and down in the hexagonal concave structure approach each other and respectively form the first upper concave part and the first lower concave part; In the hexagonal concave structure, the two vertices connected to the first upper concave part respectively form the first upper convex point and the second upper convex point; the two vertices connected to the first lower concave part respectively form the first lower convex point and the second lower convex point; In the hexagonal concave structure, the connection line between the first upper convex point and the first lower convex point and the connection line between the second upper convex point and the second lower convex point together form the connection line group; and the adjacent two hexagonal concave structures share the same connection line.

5. The anti-displacement artificial heart valve stent according to claim 2, characterized in that: The expansion unit includes a hexagonal frame, an upper curve and a lower curve; The upper curve and the lower curve are symmetrically distributed up and down and fixed on the hexagonal frame. The lower curve is in a U-shape, and the middle part of the U-shape is located inside the hexagonal frame and forms the corresponding first upper concave part and the first lower concave part; the two ends of the upper curve respectively form the first upper convex point and the second upper convex point, and the two ends of the lower curve respectively form the first lower convex point and the second lower convex point; The upper vertex of the hexagonal frame forms the first conduction part, and the lower vertex of the hexagonal frame forms the second conduction part.

6. The anti-displacement artificial heart valve stent according to claim 1, characterized in that: The inflow section, the transition section, the expansion section and the outflow section are integrally formed.

7. The anti-displacement artificial heart valve stent according to claim 1, characterized in that: The range of the change of the Poisson's ratio v of the expansion section is -1≤v<0.

8. The anti-displacement artificial heart valve stent according to claim 1, characterized in that: The ratio of the axial length of the inflow section to the transition section and the ratio of the axial length of the outflow section to the transition section are both 1:(4.5~6); the ratio of the axial length of the expansion section to the transition section is 1:(2~3); The axial length of the bracket body is 35mm~39mm; and the diameters of the openings at the inflow end and the outflow end are both 17.5mm~32.5mm.

9. The anti-displacement artificial heart valve stent according to claim 1, characterized in that: One end of the transition section close to the inflow section is in a flared shape and is connected to the expansion structure of the inflow section; One end of the expansion section close to the outflow section is in a flared shape and is connected to the expansion structure of the outflow section.

10. The anti-displacement artificial heart valve stent according to claim 1, characterized in that: The bracket body is made of a shape memory alloy material.

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