JPH1147169A - Artificial heart valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inhibit the generation of a stagnant area, etc., which may cause thrombosis, etc. SOLUTION: A heart valve comprises an annular valve seat 300, a valve 400, and triangular rotating support 500 provided on the valve seat 300. The valve 400 comprises an upstream curved surface part 46 and a downstream curved surface part 45. The valve seat 300 and the valve 400 are supported by inserting a rotary ear-shaped part 44, which is formed at a projecting part at each end of the circle of the valve 400, into a recess 33 in the rotary support 500. The rotary ear-shaped part 44 rotates according to changes in the curved surface parts 45, 46 of the valve 400, and the recess 33 is so formed to coincide with the rotation of the rotary ear-shaped part 44. At the downstream curved surface part of the rotary ear-shaped part 44, the position of the valve 400 is controlled by the contact of the curved surface of the rotary ear-shaped part 44 with the recess 33 when the valve 400 is opened or closed. At the upstream curved surface part of the rotary ear-shaped part 44, the position of the valve 400 is controlled by the contact of the end face of the rotary ear- shaped part 44 with the bottom surface of the recess 33 when the valve 400 is opened or closed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a prosthetic heart valve, in particular,
The present invention relates to a tricuspid prosthetic heart valve.

[0002]

BACKGROUND OF THE INVENTION Heart valves act as hydraulic valves in the blood circulation system to maintain blood flow in the same direction and to control blood flow to the heart. Heart valves lose their function due to lesions or degeneration.

[0003] Lesioned or degenerated heart valves lead to valvular insufficiency or stenosis. Valve insufficiency is a phenomenon in which blood flows backward because the valve is not completely closed, and valve stenosis is a phenomenon in which blood resistance increases because the valve is not completely opened. These phenomena increase the load on the heart. In order to reduce such a burden on the heart, it is necessary to replace the heart valve with an artificial heart valve by a surgical operation.

[0004] Heart valve replacement surgery is a complete and effective treatment for terminally ill patients with valvular heart disease. 19 artificial heart valves
Starr Edward in the United States in 1966
Since it was first commercialized under the name, heart valve replacement surgery has become a routine clinical practice.

[0005] Artificial heart valves are broadly classified into biological valves and mechanical valves.

[0006] Biological valves consist of a drug treated pig heart valve and a bovine heart membrane. The porcine heart valve was removed from the porcine aorta, subjected to chemical treatment, and fixed to a support under low pressure (0 to 10 mmHg). The bovine heart thin film is obtained by cutting the bovine heart thin film, sewing it to a support after being subjected to a chemical treatment. Because the biovalve geometry is very similar to the normal human aortic valve, it has an excellent dynamic mechanism of cardiac blood flow, and by the 1970s, it was about 70% of the clinical market. Came to occupy. However, biological valves have limited durability due to calcification. For example, five years after surgery, the biovalve begins to deform and requires reoperation. On the other hand, mechanical valves are more durable and do not require reoperation for many years after surgery. For this reason, the share of the biovalve in the clinical market has fallen and is now less than 30%. In addition, the biological valve has a physiological calcification rate (physiology calcifi
Not suitable for young patients due to high cation), suitable for patients over 65 years old.

On the other hand, mechanical valves are classified into ball valves, inclined single circular valves and bicuspid valves according to their geometric structures. Neither mechanical valve can avoid clinical problems such as thrombosis, and therefore must take anticoagulants for extended periods of time.

[0008] As blood flows through the mechanical valve, an occluder located on the blood passage moves, producing different effects depending on the type of valve. That is, a ball valve produces peripheral blood, a tilted single circular valve produces lateral blood flow, and a bicuspid valve produces central blood flow. In any mechanical valve, a disturbance such as a vortex, a stagnation region, turbulence, and cavitation occurs behind the closure. These disturbances are thought to be a major factor in thrombus formation. According to long-term clinical observations, bicuspid valves are generally less likely to be a thrombus type than tilted single-circle valves, and are therefore relatively popular at present.
Among them, the SJM (ST. Jude Medical) valve is most widely used. Also, from a hydrodynamic point of view, the blood flowing through the bicuspid valve has less unevenness and less turbulence than the other two valves. However, in a bicuspid valve, since the two valves cross the center of the valve seat, the flow field is split into three jet streams, and due to the non-simultaneous opening and closing of the two valves, the flow field at both ends is reduced. Jet flow lacks axial symmetry. This results in an asymmetric velocity distribution and large velocity gradients and turbulence. In order to improve such disadvantages, a tricuspid prosthetic valve has been proposed.

In the first conventional tricuspid prosthetic valve (see US Pat. No. 4,416,029, Nov. 2, 1983).
On the second day, each valve is made up of a disk divided into three parts, and the opening and closing of the valve is controlled by six support rods extending from the inner peripheral side of the valve. When the valves are fully open, the three valves open and extend toward the center of the valve annulus. A wake is formed as the blood passes through the support rods and valves.

In the second conventional tricuspid prosthetic valve (see US Pat. No. 4,820,299, issued on Apr. 11, 1989), the valve has an arc shape, and the valve is opened and closed. It is controlled by three hooks on the valve seat.

In a third conventional tricuspid prosthetic valve (see US Pat. No. 5,207,707, issued May 4, 1993), the valve is provided inside the annulus. These valves have a flat plate shape, and have a hexagonal opening in the center when the valves are fully opened. In addition, three half-moon-shaped openings that are not completely related to central blood flow are formed at the edge of the ring.

In a fourth conventional tricuspid prosthetic valve (see US Pat. No. 5,522,886, Jun. 4, 1996), the valves are arcuate and downstream of these valves. The shape of the side is a sine wave shape that is convex on the inside and concave on the outside, and the rotation axis is elliptical, and is rotatable by a concave groove inside the valve seat.

In a fifth conventional tricuspid prosthetic valve (see US Pat. No. 5,628,791, May 13, 1997), the valve is in the form of a flat plate.

[0014]

However, in the above-described first to fifth conventional tricuspid prosthetic valves, there is a problem that the blood flow field when fully opened is not ideal and a thrombus is formed. there were.

[0015]

Means for solving the above-mentioned problems include a center-flow type artificial heart valve which is open at the center and through which blood flows, and which is similar to the opening and closing method of an aortic valve in a human body. By using this valve, the curvature of the valve at the time of full opening is approximated to a circle, and the effective opening area is increased, thereby increasing the blood outflow.

[0016] Further, by reducing the protruding altitude of the valve and reducing the altitude cross-sectional difference of the valve when the valve is opened, separation of the boundary layer under barotropic pressure is eliminated, and generation of pressure drop and turbulence is suppressed.

Further, the fulcrum of the valve is a small triangular rotary support protruding inside the valve seat, which opens and closes quickly by searching for a rotation and sliding method, thereby reducing the generation of circulating flow. The height of the support ring is sufficient to mount the valve and does not affect the pressure drop. This overall design philosophy solves the problem of thrombosis caused by fluid dynamics and allows the prosthetic valve to reach an ideal range.

Further, when the valve is closed, the entire valve has a conical appearance. On the other hand, when the valve is opened, the entire valve assumes a shape in which the petals are opened, and the most preferable flow field is obtained.
The valve consists of three fan-shaped valves with arcs, which when fully open prevent separation of the boundary layer, reduce the pressure differential and thus prevent the formation of stagnation areas, between the blood and the valve during opening and closing and Relieves shock between blood and tube wall.

[0019]

FIG. 1 is a perspective view showing an embodiment of a tricuspid prosthetic heart valve according to the present invention, wherein (A) shows an open state and (B) shows a closed state. In FIG. 1, the heart valve includes an annular valve seat 300, a valve 400, and a triangular rotation support portion 500 provided on the valve seat 300. The central passage on the inner surface of the valve seat 300 is the main passage for blood to flow through the heart valve. The valve seat 300 is primarily designed to secure the valve 400 while reducing interference with blood flow.
The valve 400 includes an upstream curved surface portion 46 and a downstream curved surface portion 45. That is, the valve 400 has a fan-shaped arc surface that is concave on the blood inflow side and convex on the outflow side. Valve seat 300 and valve 40
“0” is supported by inserting the rotary ear portions 44 formed at the convex portions at both ends of the arc of the valve 400 into the concave portion 33 of the rotary support portion 500 of the valve seat 300. Thereby, the valve 4
00 rotates spontaneously without opening the valve seat 300 to control the opening and closing of the valve 400, thereby promoting forward flow of blood and preventing reverse flow of blood flow. The rotating ear 44 is a valve 400
The concave portions 33 of the rotation support portion 500 are formed so as to coincide with the rotation of the rotary ear portions 44. When the valve 400 opens and closes, the curved surface of the rotary ear 44 and the concave portion 33 of the rotary support 500 contact the valve 40 at the downstream curved surface of the rotary ear 44.
The position of 0 is controlled. On the other hand, the position of the valve 400 is controlled by the contact between the end face of the rotary ear portion 44 and the bottom surface of the concave portion 33 of the rotary support portion 500 when the valve 400 is opened and closed on the upstream curved surface portion of the rotary ear portion 44.

The valve seat 300 is designed to regulate the smooth opening and closing of the valve 400 and to reduce unwanted protrusions and eliminate obstructions in the flow field.

FIG. 2 is a top view of the valve seat 300 of FIG.
Three triangular protrusions are used as the rotation support portion 500 in the valve seat 3.
The convex portion is formed with a concave portion 33 for supporting the valve 400.

FIG. 3 is a sectional view of FIG. 2, wherein (A) is a sectional view taken along line AA of FIG. 2, and (B) is a sectional view taken along line BB of FIG. As shown in FIG. 3, the outer wall 34 of the valve seat 300 is formed to conform to the structure of the tissue annulus. The outer wall 34 and the inner wall 35 of the valve seat 300 have a smooth shape in order to prevent separation of flow fields and generation of vortices. That is, the edge portion of the valve seat 300 is rounded.

As shown in FIG. 3, the concave portion 33 of the rotation support portion 500 of the valve seat 300 is designed so that the rotation of the rotary ear portion 44 of the valve 400 is smooth. This recess 33 has a straight edge 36 and four curved edges 30, 37, 3
8, 39. Each edge 30, 36, 37, 38,
The intersection of 39 is rounded and smooth. The straight edge 36 and the curved edges 30, 37 are opened when the valve 40 is opened.
0 (FIG. 1A), and the curved edges 38, 39 show the rotating ears 44 of the valve 400 when the valve is closed.
((A) of FIG. 1). The curves of these curved edges are all quadratic curves and can be calculated by solving a polynomial equation. The plane defined by the edges 30, 36, 37, 38, 39 is parallel to the line BB in FIG. 2, and the edges 30, 36, 37, 38, 39 are perpendicular to the plane inside the recess 33. . Thus, the rotation of the valve 400 is prevented and controlled. Also, R31,
As shown in R32, it is rounded,
When the valve is closed, the recess 33 is washed with blood to prevent the formation of a stagnation region and to prevent the formation of a thrombus.

FIG. 4 is a perspective view of the valve 400 of FIG.
FIG. 5A is a perspective view as seen from the plane AA in FIG. 4, and FIG. 5B is a perspective view as seen from the plane BB in FIG. As shown in FIG. 4, the valve 400 is formed of a portion obtained by dividing the disk into three parts, and includes two straight edges 48 and 49 and a curved edge 51. As shown in FIG. 5A, the valve 400 is divided into an upstream curved surface portion 46 and a downstream curved surface portion 45, and the valve 400
Is uniform throughout. Also, the curved edge 51
Is a quadratic curve.

The straight edges 48 and 49 in FIG. 4 are curved as shown in FIG.
0 comrades can exactly match. Curved edge 4
At the intersection of 8 and the upstream curved surface 46, a radius R is added,
This prevents overlapping of the valves and facilitates opening and closing of the valves. The surface 54 adjacent to the curved edges 48 and 49 is a vertical surface, and is parallel to the BB plane in FIG. Therefore, the surface 54 is parallel to the surface of the recess 33 and is adjacent at a small distance 55 (see FIG. 6B), so that there is no wear between these surfaces during valve rotation.

As shown in FIG. 5B, the curved edge 5
Reference numeral 1 denotes a curved portion of the valve 400. As shown in FIG. 5A, the curved edge 51 is rounded and the curved surface portion 50 is formed.
Is formed naturally and intersects the downstream curved surface portion 45 at a line 56. This roundness R prevents the arc portion of the downstream curved surface portion 45 from overlapping with the inner wall 35 of the valve seat 300.

As shown in FIG. 5A, the rotary ear portions 44 at both ends of the valve 400 adjacent to the surface 54 and the curved surface portion 50 have an ear shape. The change in the curved surface 57 of the rotating ear 44 is similar to the change in the curved edge 48. The roundness of the curve 59 of the curved surface portion 50 is indicated by R, and the lower half of the curve 59 coincides with the curved surface 57 of the rotating ear portion 44, thereby connecting the valve 400 to the rotating support portion 500 of the valve seat 300. Fix it. That is, when the valve 400 is opened and closed, the lug-shaped rotary shaft 44 moves within the concave portion 33 of the rotary support portion 500, so that the
The opening and closing angle of 0 is controlled. For example, when the valve is fully open, the maximum opening is obtained, and in this embodiment, the valve is of a center flow type, so that boundary layer separation and pressure difference can be reduced. Also, regardless of whether the blood flow is on or off, the valve 400 opens and closes quickly in response to reduce the backflow of blood.

The valve 400 is incorporated in the valve seat 300. This incorporation utilizes the fact that the valve 400 expands when heated and contracts when cooled, so that the rotating ear 44 of the valve 400 is
Is carried out by fitting into the concave portion 33 of the rotation support portion 500.

A small gap is provided between the rotary ear portion 44 of the valve 400 and the concave portion 33 of the rotary support portion 500 of the valve seat 300, so that the valve 400 smoothly rotates in the concave portion 33, Wear on the contact surface of the motor is reduced. Similarly, a small gap is also provided between the vertical surface 54 of the valve 300 and the surface of the recess 33 to reduce wear on these contact surfaces. Since the valve 400 is opened by a smooth mechanism, the valve 400 is stably opened even if the blood flow is small. By providing the rotary ear-shaped portion 44, the occupied volume is smaller than when the rotary shaft is provided in the valve 400. In addition, the rotating ear portion 44 is formed by the concave portion 33 of the rotating support portion 500 of the valve seat 300.
The valve 400 is less likely to vibrate because it is in contact with the side surface of the valve.

FIG. 6A is a side view of the prosthetic valve of FIG. 1A, and FIG. 6B is a view from the BB plane of FIG. 6A. During systole of the heart, ventricular blood pressure is greater than aortic blood pressure. Thus, valve 400 receives a forward force,
The valve 400 rotates along the rotation axis O shown in FIG.
Will open naturally. At this time, the valve 400 and the valve seat 30
0 is at a right angle, so that the upstream curved surface 46 of the valve 400 and the direction of blood flow 60 are parallel. As shown in FIG. 6B, when the valve 400 is fully opened, the resistance of the blood flow flowing through the heart valve is minimized, and the opening area is maximized. At the point of contact between the rotary ear 44 of the valve 400 and the surface of the recess 33 of the rotary support 500 of the valve seat 300, the lower half of the rotary ear 44 and the curved edge 38 contact the bottom of the recess 33; The curved surface 59 and the curved edge 38 of the rotary ear 44 contact the side surface of the recess 33 to control the opening angle of the valve 400.

During the diastole of the heart, the blood pressure in the aorta gradually becomes higher than the blood pressure in the ventricles, and the valve immediately closes due to the negative pressure and eddies formed in the aorta. That is, when the heart is in a diastole, the blood flow is reversed. Therefore, at the beginning of the relaxation period, the downstream curved surface portion 45 of the valve 400 acts on the blood flow in the opposite direction, and the valve 400 starts rotating in the closing direction. At this moment, the resistance of the blood flow flowing through the surface of the valve 400
The zero closing operation is promoted. As a result, the valve 400 smoothly rotates along the rotation axis O, and the valve shifts from the open state to the closed state. Here, the curved edges R31, R32 of the concave portion 33
(See FIG. 3) is formed based on the turning radius of the rotating ear 44.

FIG. 7 (A) is a side view of the artificial valve of FIG. 1 (B), and FIG. 7 (B) is a view as seen from plane BB of FIG. 7 (A). The upper half of the rotating ear 44 contacts the straight edge 36, the curved edge 37 and the side surface of the bottom surface of the recess 33, and the curved surface 59 of the rotating ear 44 contacts the side surface of the recess 33. Further, when the valve is closed as shown in FIG. 7B, the curved edge 51 of the valve 400 coincides with the inner wall 35 of the valve seat 300, and the linear edge 4 of the valve 400
8, 49 and their end points 52 coincide with each other, thereby facilitating the end of the valve closing operation.

In summary, the end of the valve opening operation is as follows.
(1) The curved edge 3 of the portion of the rotating ear 44 and the concave portion 33
(2) Curved surface 59 of rotating ear 44 and recess 3
3 in contact with the curved edge 39. On the other hand, the end of the valve closing operation is determined by (1) the contact between the portion of the rotating ear portion 44 and the linear edge 36 of the concave portion 33, and (2) the curved surface 59 of the rotating ear portion 44 and the curved edge 30 of the concave portion 33. (3) contact between the curved edge 51 of the valve 400 and the inner wall 35 of the valve seat 300, (4) straight edge 48 of the valve 400,
49, and (5) the contact of the end point 52 of the valve 400, whereby the regurgitation of the valve can be reduced and the leakage of blood flow can be suppressed.

In the closed state, the valve 400 forms an angle of 30 ° with the valve seat 300 as shown in FIG. In other words, the valve 400 makes a 60 ° angle with the direction of blood flow. Therefore, the opening / closing angle of the valve 400 is 60 °.

By comparing FIG. 6B and FIG. 7B, the change of the valve 400 from the open state to the closed state can be inferred.
That is, since the side of the valve 400 gradually approaches the center, the impact of the blood flow on the tube wall is reduced, and the occurrence of turbulence is suppressed.

Although the preferred embodiment of the present invention has been described above, it is not intended to limit the present invention, and any person skilled in the art can modify the present invention within the scope described in the claims. It includes the range which can be performed.

[0037]

As described above, according to the present invention, since the valve has a fan-shaped arc surface that is concave on the inflow side and convex on the outflow side, the curvature of the valve approaches a circle when fully opened, and As a result, an ideal flow field can be obtained, and the effective opening area can be increased. Further, since the height of the valve is small, and the difference in the altitude cross-sectional area of the valve at the time of opening and closing is small, it is possible to prevent separation of the boundary layer under the forward flow of blood flow and occurrence of a stagnation region. Blood pressure drop and turbulence can be suppressed. Furthermore, since the fulcrum of the valve is provided by the rotation support portion protruding from the valve seat, the rotation of the curved valve can be made smooth. Further, opening and closing of the valve can be performed quickly.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of a tricuspid prosthetic heart valve according to the present invention, wherein (A) shows a valve open state and (B) shows a valve closed state.

FIG. 2 is a top view of the valve seat of FIG. 1;

3A and 3B are cross-sectional views of FIG. 2, wherein FIG. 3A is a cross-sectional view taken along line AA of FIG. 2, and FIG. 3B is a cross-sectional view taken along line BB of FIG.

FIG. 4 is a perspective view of the valve of FIG. 1;

5 is an enlarged view of FIG. 4, wherein FIG. 5 (A) is a perspective view seen from the plane AA of FIG. 4, and FIG. 5 (B) is a view BB of FIG.
It is the perspective view seen from the surface.

6 (A) shows the artificial valve of FIG. 1 (A), FIG. 6 (A) is a side view of the artificial valve of FIG. 1 (A), and FIG. 6 (B) is FIG. 6 (A). It is the figure seen from BB plane.

7 shows the artificial valve of FIG. 1 (B), FIG. 7 (A) is a side view of the artificial valve of FIG. 1 (B), and FIG. 7 (B) is a view of FIG. 7 (A). It is the figure seen from BB plane.

[Explanation of symbols]

 30: Curved edge 33: Concavity 34: Outer wall 35: Inner wall 36: Straight edge 37: Curved edge 38: Curved edge 39: Curved edge 44: Rotating ear 45: Downstream curved surface 46: Upstream curved surface 47: Thick 48: Straight edge 49: Straight edge 50: Curved surface 51: Curved edge 52: End point 54: Surface 55: Distance 56: Line 57: Curved surface 58: Rotating ear portion 59: Curved surface 60: Blood flow direction 61: Bottom 300: Valve seat 400: Valve 500: Rotation support R31: Roundness R32: Roundness

Claims (21)

[Claims] 1. A valve seat (300) having a central passage for blood provided on an inner wall (35) side, and a plurality of rotary supports (500) having a concave portion (33) protruding from the inner wall side of the valve seat. And a plurality of valves (400) having a concave upstream curved surface (46) concave on the blood inflow side and a convex downstream curved surface (45) on the blood outflow side. Prosthetic heart valve, wherein the bottom of the valve is not fitted in the corresponding recess of the rotation support portion, and the opening and closing operation of each valve is restricted by the recess. 2. The artificial heart valve according to claim 1, wherein the number of the valves is three. 3. Each of said valves has two straight edges (48, 4).
9) and a curved edge connecting the two straight edges (51)
When the valve is closed, the straight edges of the adjacent valves coincide with each other,
The artificial heart valve according to claim 1, wherein a curved edge of each valve coincides with an inner wall of the valve seat. 4. The artificial heart valve according to claim 3, wherein a curved edge of each valve is rounded. 5. Each of said valves has a substantially arcuate sector of one third of a circle, the two straight edges of each of said valves being 12
4. The prosthetic heart valve according to claim 3, which forms an angle of 0 °. 6. The prosthetic heart valve according to claim 1, wherein the bottom of each valve is an ear-shaped rotating ear. 7. The side surface of the rotary ear portion has the same shape as the side surface of the straight edge of the valve, and the lower half of the rotary ear portion matches the roundness of the curved edge of the valve. 2. The artificial heart valve according to item 1. 8. The artificial heart valve according to claim 1, wherein the valve has a gap between the valve and an inner wall of the valve seat when the valve is opened and closed. 9. The valve according to claim 9, wherein the number of the valves is three, and a curved edge of each of the valves is approximated to a one-third arc to represent a curved curvature of each of the valves. The artificial heart valve according to claim 8, wherein a rounded portion is provided at an intersection with the portion. 10. The method according to claim 1, wherein the recess has one straight edge (3
6) and four curved edges (30, 37, 38, 39)
2. The prosthetic heart valve according to claim 1, wherein the prosthetic heart valve has a closed surface defined by: 11. The prosthetic heart valve according to claim 10, wherein two of the curved edges are formed based on a turning radius of the rotating ear portion in the recess. 12. The prosthetic heart valve according to claim 11, wherein the depth of the concave portion is larger than the depth of the rotating ear portion accommodated in the concave portion. 13. The position of the concave portion according to claim 12, wherein the position of the concave portion is determined based on the fact that the center of rotation on the wall surface of the concave portion and the center point on the projecting surface of the valve seat are the same point. Artificial heart valve. 14. A portion of the valve seat protruding from the upstream end, an oblique plane is cut out toward the upstream end, the plane is similar to a triangular plane, and three vertices of the plane are 14. The valve seat according to claim 13, wherein the protruding double wall of the valve seat intersects with a point where the protruding portion of the valve seat intersects with the end on the side where blood flows and the valve seat intersect. An artificial heart valve as described. 15. When the valve is fully opened, the lower halves of the rotary support portion, which correspond to the lower half portion of the concave portion of the upstream curved surface portion of the rotary ear portion, are in contact with each other, and the downstream side of the rotary ear portion. 2. The artificial heart valve according to claim 1, wherein the curved surface portion and a surface in which the upper half curved portion of the concave portion is dug down vertically face to face, thereby controlling the valve opening operation of the valve seat. 3. . 16. When the valve is opened and closed, a curved surface corresponding to a side surface of the rotary ear and a bottom surface of the concave portion come into contact with rotation of a central axis, and a gap is left between the two surfaces. 16. The artificial heart valve according to 15. 17. When the valve is fully closed, a curve corresponding to an upper half of an upstream curved surface of the rotary ear portion and a side of an upper half side of the concave portion in the rotary support portion are in contact with each other side by side, The side representing the thickness where the vertical surface corresponding to the side surface of the valve and the curved surface corresponding to the side surface of the rotary ear portion are in contact with each other, and the straight edge of the concave portion are in contact with each other side by side. An artificial heart valve as described. 18. When the valve is fully closed, a curved surface corresponding to a lower half portion of a downstream curved surface portion of the rotary ear portion and a surface obtained by vertically dug down a lower half curve of the concave portion come into face-to-face contact with each other. An artificial heart valve according to claim 17. 19. The artificial heart valve according to claim 18, wherein when the valve is fully closed, an arc segment of an upstream curved surface portion of the valve and an inner wall of the valve seat are in side-to-side contact with each other. 20. The artificial heart valve according to claim 19, wherein when the valve is fully closed, two sides of the front valve are in face-to-face contact with two sides of another valve. 21. The valve according to claim 20, wherein, when the valve is fully closed, a vertex at which the two sides of the valve intersect and a vertex of the other two valves are adjacent to each other on a vertical side representing the thickness. Artificial heart valve.