WO2024160194A1 - Artificial heart valve - Google Patents

Abstract

An artificial heart valve (100), comprising at least two leaflets (110), wherein the leaflets (110) are made of a polymer material, the at least two leaflets (110) are arranged in a circumferential direction of the artificial heart valve (100), adjacent leaflets (110) are connected to each other at a leaflet junction (112), and the artificial heart valve (100) does not close in a natural state thereof. A prosthesis of an artificial heart valve, the prosthesis comprising an expandable stent and an artificial heart valve (100), wherein each leaflet (110) of the artificial heart valve (100) has a curved surface structure, the contour of a curved surface is formed by an upper curve (114) and a lower curve (116), and at least part of the lower curve (116) is connected to the stent. The artificial heart valve (100) has a non-closed form in the natural state thereof, so that a transvalvular pressure gradient of the valve in an open state can be effectively reduced, thereby significantly improving the hydrodynamic performance of the polymer valve; moreover, the problem of leaflet stress concentration can be obviously alleviated, which is conducive to prolonging the fatigue life of the leaflets.

Description

An artificial heart valve

For all purposes, this application claims priority to Chinese Patent Application No. 202310044581.8 filed on January 30, 2023, and the contents of the above-mentioned Chinese patent application disclosure are hereby incorporated by reference in their entirety as a part of this application.

Technical Field

The present disclosure relates to an artificial heart valve, and in particular to an artificial heart valve made of a polymer material.

Background Art

There are some problems with the currently used mechanical artificial heart valves and biological artificial heart valves for the treatment of heart valve diseases. If patients choose to implant a mechanical valve, they will need to take anticoagulants for life to avoid a certain degree of thrombosis risk caused by the mechanical valve, and they will also face the risk of bleeding. If patients choose to implant a biological valve, they will face problems such as valve calcification, decay, and short lifespan, which limits the application of biological valves in young patients.

As an effective technical alternative to biological valves, polymer valves have great design flexibility and a wide range of material properties. In addition, polymer valves can withstand higher damage tolerance during surgery, thereby extending durability. Therefore, polymer valves are expected to bring good news to many young and middle-aged patients with rheumatic heart disease.

Summary of the invention

The present disclosure provides an artificial heart valve, which includes at least two leaflets, which are made of polymer materials, at least two leaflets are arranged along the circumference of the artificial heart valve, adjacent leaflets are connected at the leaflet junction, and the artificial heart valve is non-closed in a natural state.

In one embodiment, the polymer material is one or more of polytetrafluoroethylene, polyurethane, poly(styrene-b-isobutylene-b-styrene) or silica gel.

In one embodiment, the leaflet has a curved surface structure, the contour of the curved surface is composed of an upper curve and a lower curve, and the upper curve and the lower curve are connected at the leaflet junction, the upper curves of adjacent leaflets do not overlap with each other, and the middle part of the upper curve is radially concave inward.

In one embodiment, the upper curve lies in the plane of a coordinate system whose X-axis is determined by the leaflet The Y axis of the coordinate system is formed by the connecting line of the leaflet junction points on both sides, the vertical line of the connecting line along the horizontal direction, ^and the upper curve of the leaflet is defined by the parameter curve Y= _anXn + _an-1Xn ^{- 1…} + _a1X1 + _a0 , where _an is a parameter and n>3.

In one embodiment, n>5.

In one embodiment, when n=6, 4.2<a ₀ <4.9, -0.004<a ₁ <-0.001, -0.8<a ₂ <-0.2, 1e ^-5 <a ₃ <8e ^-5 , 0.003<a ₄ <0.005, -8e ^-7 <a ₅ <-1e ^-7 , and -5e ^-5 <a ₆ <-2e ^-5 .

In one embodiment, the length of the line connecting the leaflet fusion points is 1.1-1.46 times the length of the line connecting two points at 1/2 of the height of the lower curve.

In one embodiment, the length of the line connecting the leaflet fusion points is 1.2-1.45 times the length of the line connecting two points at 1/2 of the height of the lower curve.

In one embodiment, the contour of the curved surface also includes an abdominal contour, which is a straight line; the angle between the abdominal contour and the horizontal line is in the range of 45-75 degrees.

The present disclosure also provides an artificial heart valve prosthesis, including an expandable stent and the artificial heart valve as described above, wherein the leaflets of the artificial heart valve have a curved surface structure, the contour of the curved surface is composed of an upper curve and a lower curve, and at least part of the lower curve is connected to the stent.

Compared with the existing polymer valve design, the artificial heart valve proposed in the present disclosure has a non-closed shape in the natural state, which can effectively reduce the transvalvular pressure difference when the valve is open, and significantly improve the fluid dynamic performance of the polymer valve. In addition, the maximum stress value of the non-closed polymer artificial heart valve disclosed in the present disclosure is significantly lower than that of the existing closed polymer heart valve, that is, the non-closed polymer artificial heart valve can significantly alleviate the problem of leaflet stress concentration, effectively reduce the leaflet stress in the open state, and is conducive to improving the leaflet fatigue life.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings of the embodiments will be briefly introduced below. Obviously, the drawings in the following description only relate to some embodiments of the present disclosure, rather than limiting the present disclosure.

FIG1 is a schematic diagram of an artificial heart valve in a natural state according to an embodiment of the present disclosure.

FIG. 2 is a schematic diagram of a single leaflet of an artificial heart valve in a natural state according to an embodiment of the present disclosure.

FIG. 3 is a flow detection curve of an artificial heart valve during cardiac systole according to an embodiment of the present disclosure.

4 is a horizontal view of the lower curve of a single leaflet of an embodiment of the present disclosure when the artificial heart valve is in a natural state.

Figure 5(a) shows the Mises stress distribution diagram of the valve in the open state when the length of the line connecting the leaflet junction is 1.15 times the length of the line connecting the lower curve at the height 1/2, and Figure 5(b) shows the Mises stress distribution diagram of the valve in the open state when the length of the line connecting the leaflet junction is 1.2 times the length of the line connecting the lower curve at the height 1/2.

6 is a side view of a single leaflet of an embodiment of the present disclosure when the artificial heart valve is in a natural state.

FIG7( a ) is a Mises stress distribution diagram of the valve in an open state when the abdominal contour is a curve, and FIG7( b ) is a Mises stress distribution diagram of the valve in an open state when the abdominal contour is a straight line.

FIG8( a ) is a Mises stress distribution diagram of an artificial heart valve in an open state according to an embodiment of the present disclosure, and FIG8( b ) is a Mises stress distribution diagram of an existing closed polymer valve in an open state.

DETAILED DESCRIPTION

The following will be combined with the drawings in the embodiments of the present disclosure to clearly and completely describe the technical solutions in the embodiments of the present disclosure. Obviously, the described embodiments are only part of the embodiments of the present disclosure, rather than all the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

Unless otherwise defined, all terms (including technical and scientific terms) used in the embodiments of the present disclosure have the same meanings as commonly understood by those of ordinary skill in the art to which the present disclosure belongs. It should also be understood that terms such as those defined in common dictionaries should be interpreted as having meanings consistent with their meanings in the context of the relevant technology, and should not be interpreted in an idealized or extremely formal sense, unless the embodiments of the present disclosure are explicitly defined in this way.

The words "first", "second" and similar words used in the embodiments of the present disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. Words such as "one", "an" or "the" and similar words do not indicate a quantity limitation, but rather indicate the presence of at least one. Similarly, words such as "include" or "comprise" mean that the elements or objects preceding the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. In the following description, spatial and directional terms such as "upper", "lower", "front", "back", "top", "bottom", "vertical" and "horizontal" may be used to describe the embodiments of the utility model, but it should be understood that these terms are only for the convenience of description. The embodiments shown in the figures do not require that the actual device be constructed or operated in a specific orientation. In the following description, the use of terms such as "connect", "couple", "fixed" and "attached" may refer to a direct connection between two elements or structures without other elements or structures between them, or may refer to an indirect connection between two elements or structures through an intermediate element or structure, unless otherwise expressly stated herein.

Implanting biological valves into patients will face the problems of valve calcification, decay, and short service life. Polymer valves may be an effective alternative to biological valves, with good design flexibility, wide selection of material properties, and good durability.

The inventors of the present disclosure have found that, at present, there are no products approved for clinical use of polymer valves, but there are a variety of polymer materials in the research process, such as polytetrafluoroethylene, polyurethane, poly(styrene-b-isobutylene-b-styrene) (SIBS) and silica gel. The inventors of the present disclosure have also found that the mechanical properties of polymer materials are completely different from those of biological valve materials (such as bovine pericardium, porcine pericardium) and natural valves. The elastic modulus and bending strength of polymer materials are generally higher than those of biological tissues, and they provide greater resistance to the deformation of the valve leaflets during the movement of the valve leaflets. In particular, at present, most polymer valves are similar in appearance to biological valves in their natural state, presenting an inwardly concave curved surface, and are in a closed state in their natural state, that is, there is basically no gap between adjacent valve leaflets. Because the valve leaflets of polymer materials have a certain shape memory effect, that is, the polymer valve has a tendency to maintain and restore its closed shape in its natural state, and in the process of the valve transition from closed to open, the polymer valve in the closed state requires blood to provide a higher force to resist this shape memory effect. Therefore, the polymer valves currently under research are difficult to open and close naturally with the blood flow like natural valves, and often have problems such as large transvalvular pressure difference, poor forward conduction performance of the valve for blood, and stress concentration when the valve is opened.

An artificial heart valve made of polymer material provided by an embodiment of the present disclosure solves some of the above-mentioned technical problems. The embodiment of the present disclosure and examples thereof are described in detail below in conjunction with the accompanying drawings.

FIG1 is a schematic diagram of an artificial heart valve in a natural state according to an embodiment of the present disclosure, and the artificial heart valve 100 is made of a polymer material. In one embodiment, the polymer material is polytetrafluoroethylene, polyurethane, poly(styrene-b-isobutylene-b-styrene) (SIBS) and/or silica gel, etc. According to actual needs, a combination of one or more of the above polymer materials can be used. As shown in FIG1 , the artificial heart valve 100 of this embodiment includes three leaflets 110, and the three leaflets 110 are arranged along the circumference of the artificial heart valve 100. The present disclosure is not limited to this, and the artificial heart valve 100 may also include only two leaflets, or include more than three leaflets 110. Each leaflet 110 has a curved surface structure. The contour line of the curved surface is composed of an upper curve 114 and a lower curve 116. In some embodiments, the upper curve 114 and the lower curve 116 are connected at the leaflet junction 112, and the adjacent leaflets 110 are connected at the leaflet junction. The adjacent leaflets 110 are connected at the leaflet junction 112. In this article, the adjacent leaflets 110 are "connected" at the leaflet junction 112, which means that the leaflet junction of each leaflet 110 is mutually abutted, intersected or adjacent to the leaflet junction 112 of the adjacent leaflet 110. "Adjacent" here means that, according to actual needs, the adjacent leaflets 110 may not intersect or abut, and the distance between the leaflet junctions of adjacent leaflets 110 does not exceed 1 mm. The "upper curve" in this article refers to the local contour line of the leaflet 110 near the blood outflow end of the artificial heart valve 100. The "lower curve" in this article refers to the local contour line of the leaflet 110 near the blood inflow end of the artificial heart valve 100. When the artificial heart valve 100 is in a natural state, it is in a non-closed shape. The "natural state" in this article refers to the state in which the artificial heart valve 100 of the present disclosure is not subjected to any external force, or the state before implantation. Herein, the artificial heart valve 100 is in a "non-closed form" means that when the artificial heart valve 100 is in a natural state, the upper curves 114 of adjacent leaflets 110 present inconsistent bending states, so that the upper curves 114 of adjacent leaflets 110 do not overlap. In other words, there is a gap between the upper curves 114 of adjacent leaflets, so that the artificial heart valve is in an incompletely closed form in the natural state. As shown in Figure 1, the middle part of the upper curve 114 is radially concave inward. Herein, "radial" refers to the diameter direction of the artificial heart valve 100. It should be noted that after the artificial heart valve 100 disclosed in the present invention is implanted, the valve will open and close normally under the action of blood flow, wherein in the closed state, the upper curves 114 of adjacent leaflets 110 basically overlap under the action of blood flow without the existence of gaps. According to an in vitro pulsating flow test, in an operating environment simulating a natural heart, the regurgitation volume of the artificial heart valve 100 of an embodiment of the present disclosure in a closed state is 3.7%, which is no different from the regurgitation volume of a healthy native heart valve.

FIG2 is a schematic diagram of a single leaflet of an embodiment of the present disclosure when the artificial heart valve is in a natural state. As shown in the figure, the upper curve 114 is located in the plane of the coordinate system, the X-axis of the coordinate system is formed by the line connecting the leaflet junctions 112 on both sides of the leaflet 110, and the Y-axis of the coordinate system is formed by the vertical line of the line along the horizontal direction. Here, the "horizontal direction" refers to the direction parallel to the radial direction of the artificial heart valve 100. The upper curve 114 of the leaflet 110 is defined by the parameter curve Y=a _n X ⁿ +a _n-1 X ^n-1… +a ₁ X ¹ +a ₀ , where a _n is a parameter, n>3. In some embodiments, n is set to n>5, and the actual working effect of the leaflet 110 of the embodiment of the present disclosure is better, and the fluid dynamic performance of the artificial heart valve 100 is increased. Specifically, during the process of opening the artificial heart valve 100 and when it is in the open state, the transvalvular pressure difference of the artificial heart valve 100 is reduced, thereby having better hemodynamics. The "open state" herein refers to the state of the artificial heart valve 100 when the chamber of the heart contracts. At this time, the artificial heart valve 100 is opened by the force of blood flow from the inflow end to the outflow end. The "transvalvular pressure difference" herein refers to the difference in blood pressure between the inflow end and the outflow end of the heart valve or blood vessel valve. Aortic valve, "transvalvular pressure gradient" refers to the difference between aortic pressure and left ventricular pressure. The transvalvular pressure gradient of a healthy aortic valve is close to zero, at which time blood can flow from the left ventricle into the aorta unimpeded. Therefore, the smaller the transvalvular pressure gradient of the artificial heart valve 100, the smaller the resistance when the valve opens, and the closer to the ideal clinical effect.

The inventors of the present disclosure have also conducted fluid pressure detection on the artificial heart valve 100 of the embodiment of the present disclosure. FIG3 is a fluid detection curve of the artificial heart valve of an embodiment of the present disclosure during the cardiac contraction period. As shown in FIG3, as time goes by, the heart begins to contract, the left ventricular pressure increases rapidly, and the difference between the left ventricular pressure and the active valve pressure decreases. In the forward blood flow stage (the dotted box portion in FIG3), the artificial heart valve 100 of the embodiment of the present disclosure has a very low transvalvular pressure difference during cardiac contraction, and the peak value of the transvalvular pressure difference is 3.7 mmHg (as shown in the dotted box portion in FIG3, the left ventricular pressure at this time is slightly higher than the aortic pressure). It should be noted that, according to existing public data, under basically the same test conditions, the peak value of the transvalvular pressure difference of the closed heart valve is in the range of 8-32 mmHg. Therefore, the lower transvalvular pressure difference makes the artificial heart valve 100 of the present disclosure less likely to hinder blood flow during the opening process. Specifically, the artificial heart valve 100 made of polymer material proposed in the present disclosure has a non-closed form in a natural state, and because the artificial heart valve 100 made of polymer material has shape memory properties, in actual work, when the artificial heart valve 100 of the present disclosure is in a closed state under the action of blood flow, the shape memory property of the polymer valve itself will make the valve tend to return to its natural non-closed form. Therefore, compared with the existing closed polymer valve design, the non-closed polymer artificial heart valve 100 proposed in the present disclosure will be easier to open next time under the action of blood flow. Therefore, the artificial heart valve 100 design of the present disclosure can effectively improve the fluid dynamic performance of the valve.

In a preferred embodiment, the above parameters are taken as follows: n=6, 4.2<a ₀ <4.9, -0.004<a ₁ <-0.001, -0.8<a ₂ <-0.2, 1e ^-5 <a ₃ <8e ^-5 , 0.003<a ₄ <0.005, -8e ^-7 <a ₅ <-1e ^-7 , -5e ^-5 <a ₆ <-2e ^-5 . At this time, the curved surface of the leaflet 110 is flatter, and the fluid dynamic performance of the artificial heart valve 100 is better. Outside the above range of values, the curvature of the leaflet 110 is larger, which may make the shape of the leaflet 110 too different from that of the natural valve, resulting in its hemodynamics and other performances being affected and changed.

FIG4 is a horizontal view of the lower curve of a single leaflet of an embodiment of the present disclosure when the artificial heart valve is in a natural state. In some embodiments, the length L1 of the line connecting the two leaflet junctions 112 on a single leaflet 110 is 1.1-1.46 times, preferably 1.2-1.45 times, the length L2 of the line connecting the two points at the lower curve 116 of the leaflet 110 at 1/2 of the height. The "height" herein refers to the length of the artificial heart valve. The distance between the two farthest points of the membrane 100 in the direction from the blood outflow end to the blood inflow end in the natural state.

The inventors of the present disclosure have studied the stress distribution of artificial heart valves 100 with different leaflet shapes in the open state through finite element simulation software. For example, FIG5a is a Mises stress distribution diagram of the valve in the open state when the length L1 of the line connecting the leaflet junction is 1.15 times the length L2 of the line connecting the two points at the lower curve at the height 1/2, and FIG5b is a Mises stress distribution diagram of the valve in the open state when the length L1 of the line connecting the leaflet junction is 1.2 times the length L2 of the line connecting the two points at the lower curve at the height 1/2. In this article, "Mises stress" is an equivalent stress based on shear strain energy, also known as the paradigm equivalent stress (Von Mises Stress), which uses stress contours to represent the stress distribution inside the model, so that analysts can quickly determine the most dangerous area in the model. Here, the stress changes of valves with different leaflet shapes in the open state are mainly analyzed by comparing the maximum values of the leaflet Mises stress in FIG5a and FIG5b. According to the finite element simulation results, when the ratio of the length L1 of the line connecting the leaflet junction to the length L2 of the line connecting the two points at the lower curve at the height 1/2 is 1.15, the maximum value of the Mises stress of the leaflet of the non-closed polymer valve 100 in the open state is 9.09MPa (megapascals). When the ratio (L1/L2) increases to 1.2, the maximum value of the Mises stress of the leaflet of the non-closed polymer valve 100 in the open state is 5.98MPa, and the Mises stress is reduced by 34.2%. Therefore, by optimizing the shape of the lower curve of the leaflet of the artificial heart valve 100 disclosed in the present invention, the stress of the leaflet 110 can be effectively reduced, which is conducive to improving the fatigue life of the leaflet 110.

FIG6 is a side view of a single leaflet of an embodiment of the present disclosure when the artificial heart valve is in a natural state. In some embodiments, the abdominal contour 118 of the leaflet is a straight line. In some embodiments, the angle between the abdominal contour 118 and the horizontal line ranges from 45 to 75 degrees. The abdominal contour 118 refers to the projection of the line connecting the midpoint of the upper curve 114 and the midpoint of the lower curve 116 of the leaflet on the curved surface of the leaflet 110. Compared with the curved abdominal contour commonly possessed by existing closed polymer valves, the curved surface of the leaflet 110 of this embodiment is flatter, which can further reduce the transvalvular pressure difference of the artificial heart valve 100 made of polymer material in the open state, which is conducive to further effectively improving the fluid dynamic performance of the artificial heart valve 100.

The inventors of the present disclosure have studied the stress distribution of artificial heart valves 100 with different abdominal contour shapes in the open state using finite element simulation software. FIG7a is a Mises stress distribution diagram of a valve with a curved abdominal contour 118 in the open state, and FIG7b is a Mises stress distribution diagram of a valve with a straight abdominal contour 118 in the open state. According to the finite element simulation results, when the abdominal contour 118 is a curve, the maximum Mises stress of the leaflet of the non-closed polymer valve 100 in the open state is The value is 5.07MPa. When the abdominal contour 118 is a straight line, the maximum value of the Mises stress of the leaflet of the non-closed polymer valve 100 in the open state is 4.46MPa. Therefore, it can be seen that designing the shape of the abdominal contour into a straight line can reduce the stress of the leaflet 110, which is conducive to improving the fatigue life of the leaflet 110.

The inventors of the present disclosure also studied the stress distribution of different types of artificial heart valves 100 in the open state through finite element simulation software. Figure 8a is a Mises stress distribution diagram of an artificial heart valve 100 of an embodiment of the present disclosure in the open state, and Figure 8b is a Mises stress distribution diagram of an existing closed polymer valve in the open state. According to the finite element simulation results, the maximum value of the Mises stress of the leaflet of the non-closed polymer artificial heart valve 100 of the present disclosure embodiment in the open state is 2.11MPa, while the maximum value of the Mises stress of the leaflet of the existing closed polymer heart valve in the open state is 2.87MPa. Therefore, compared with the leaflet design of the existing closed polymer heart valve, the Mises stress of the leaflet 110 of the non-closed polymer valve 100 of the present disclosure embodiment in the open state is reduced by 26.5%. Therefore, the design of the artificial heart valve 100 of the present disclosure can effectively reduce the stress of the leaflet 110, which is conducive to improving the fatigue life of the leaflet 110.

The present disclosure also provides an artificial heart valve prosthesis, including an expandable stent and the artificial heart valve 100 as described above, wherein the leaflet 110 of the artificial heart valve 100 has a curved surface structure, the contour of the curved surface is composed of an upper curve 114 and a lower curve 116, and at least a portion of the lower curve 116 is connected to the stent. As described above, in actual work, when the artificial heart valve 100 of the present disclosure is in a closed state under the action of blood flow, the shape memory property of the polymer valve itself will make the valve tend to return to its natural state of non-closed form. Thus, compared with the existing closed polymer valve design, the non-closed polymer artificial heart valve 100 proposed in the present disclosure will become easier to open next time under the action of blood flow. Therefore, the artificial heart valve 100 of the artificial heart valve prosthesis of the present disclosure will obtain more excellent fluid dynamic performance and anti-fatigue performance.

Compared with the existing polymer valve design, the artificial heart valve proposed in the present disclosure has a non-closed form in the natural state, which can effectively reduce the transvalvular pressure difference when the valve is open, and significantly improve the fluid dynamic performance of the polymer valve. In addition, the maximum stress value of the non-closed polymer artificial heart valve disclosed in the present disclosure is significantly lower than that of the existing closed polymer heart valve, that is, the non-closed polymer artificial heart valve can significantly alleviate the problem of leaflet stress concentration, effectively reduce the leaflet stress in the open state, and is conducive to improving the leaflet fatigue life.

There are a few points to note:

(1) The drawings of the embodiments of the present disclosure only relate to the structures involved in the embodiments of the present disclosure, and other structures may refer to the general design.

(2) In the absence of conflict, the embodiments of the present disclosure and the features therein may be combined with each other to obtain new embodiments.

The above are only specific implementations of the present disclosure, but the protection scope of the present disclosure is not limited thereto, and the protection scope of the present disclosure shall be based on the protection scope of the claims.

Claims (10)

An artificial heart valve, characterized in that the artificial heart valve comprises at least two leaflets, the leaflets are made of polymer material, the at least two leaflets are arranged along the circumference of the artificial heart valve, adjacent leaflets are connected at the leaflet junction, and the artificial heart valve is non-closed in a natural state. The artificial heart valve according to claim 1, characterized in that the polymer material is a combination of one or more of polytetrafluoroethylene, polyurethane, poly(styrene-b-isobutylene-b-styrene) or silica gel. The artificial heart valve as described in claim 1 or 2 is characterized in that the leaflet has a curved surface structure, the contour of the curved surface is composed of an upper curve and a lower curve, and the upper curve and the lower curve are connected at the leaflet junction, the upper curves of adjacent leaflets do not overlap with each other, and the middle part of the upper curve is radially concave inward. The artificial heart valve according to claim 3, characterized in that the upper curve is located in the plane of a coordinate system, the X-axis of the coordinate system is formed by a line connecting the leaflet junction points on both sides of the leaflet, the Y-axis of the coordinate system is formed by a vertical line of the line along the horizontal direction, and the upper curve of the leaflet is defined by ^a parameter curve Y= _anXn ⁺ _an- ^1Xn-1 …+ _a1X1 + _a0 , wherein _an is a parameter and n>3. The artificial heart valve as described in claim 4 is characterized in that n>5. The artificial heart valve according to claim 4 or 5, characterized in that, when n=6, 4.2< _a0 <4.9, -0.004< _a1 <-0.001, -0.8< _a2 <-0.2, 1e ^-5 < _a3 <8e ^-5 , 0.003< _a4 <0.005, -8e ^{- 7} < _a5 <-1e ^-7 , -5e ^-5 < _a6 <-2e ^-5 . The artificial heart valve as described in any one of claims 3 to 6 is characterized in that the length of the line connecting the leaflet junctions is 1.1 to 1.46 times the length of the line connecting two points at 1/2 of the height of the lower curve. The artificial heart valve as described in claim 7 is characterized in that the length of the line connecting the leaflet junctions is 1.2-1.45 times the length of the line connecting two points at 1/2 of the height of the lower curve. The artificial heart valve as described in any one of claims 3-8 is characterized in that the contour of the curved surface also includes an abdominal contour, and the abdominal contour is a straight line; the angle between the abdominal contour and the horizontal line ranges from 45 to 75 degrees. An artificial heart valve prosthesis, characterized in that it comprises an expandable stent and an artificial heart valve as claimed in any one of claims 1 to 9, wherein the leaflet of the artificial heart valve has a curved surface. The structure comprises an upper curve and a lower curve, and at least a portion of the lower curve is connected to the bracket.