JPH0337667B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a medical valve device having a valve seat and a movable valve body, such as an artificial valve for an artificial heart.

B. Prior Art In recent years, progress has been made in the development of artificial hearts for auxiliary and temporary replacement of the functions of the heart outside the body during open-heart surgery and other surgeries. For example, as shown in FIG. 6, a sac-type blood pump device 11 is connected between the right atrium and the pulmonary artery and the left atrium and the aorta of a living body's heart 10, respectively. Such blood pump devices are being researched in Japan ahead of the rest of the world, and have already been put into clinical use as auxiliary hearts.

This blood pump device 11 is of the so-called sack type, and as shown in FIG. It consists of a blood chamber 2 in the form of a flat bag to be housed. In the upper part of the blood chamber 2, a blood introduction tube 3 and a blood discharge tube 4, which communicate with the blood chamber, are formed upward and substantially parallel to each other. A flange portion 5 forming a part of the housing is provided around the upper portion of the blood chamber portion, and the blood chamber is hermetically housed within the housing outer case 1 by this flange portion. In addition, artificial check valves 6 and 7 are installed inside each of the blood introduction tube 3 and the blood discharge tube 4 to prevent the blood 17 from flowing back. The blood 17 introduced therein is pumped out from the blood discharge tube 4. Blood pumping is
By alternately introducing and discharging fluid such as compressed air and decompressed air through the port 8 provided at the bottom of the housing outer case 1, the blood chamber repeats expansion and contraction as the external pressure of the blood chamber changes. It is what is done. Each cannula 12 and each blood conduit 3 and 4 on the blood chamber 2 side, which are connected to the heart of the living body by anastomosis, are connected to a ring-shaped flange provided from both ends of each connector 13 to the center thereof. They are inserted up to position 14 respectively.

In this way, in the blood pump device, for example, the artificial valves 6 and 7 include disk-type artificial valves,
Ball-shaped artificial valves are also used. In particular, for ball-type valves, the movable valve is made of a ball, so
It has the advantage of being more durable and less likely to generate blood clots than the disk type. However, with all artificial valves, struts and cages are installed in the blood flow path to hold the movable valve body, so when blood flows, the struts and cages disturb the blood flow.
In some cases, blood clots may occur.

As a ball-type artificial valve without a strut or cage, an artificial valve 20 shown in Figs. 8 and 9 is used.
is possible. This artificial valve 20 has two main body parts 2.
0a and 20b, and each part has a valve seat 21 on which a ball (movable valve body) 28 can be attached and detached.
a and 21b are respectively formed. In addition, the valve seat 21
As shown in FIG. 9, a is formed by a groove 23 of a larger diameter cut in contact with both ends of a circular flow path 22 forming a blood flow path. Therefore, the flow path 22 faces the back of this groove 23, and the valve seat 21
A is formed as a substantially right-angled step on both sides of the flow path 22. Further, at the bottom of the groove 23, the inner surface 25 of the main body forms a substantially right-angled surface and is located above and below the flow path 22. On the other hand,
The valve seat 21b has a shape that seems to form part of a spherical surface, and is connected to the flow path 24 similar to the above-mentioned 22, but the flow path 24 is connected to the valve seat 21b by a ball 28 like a dashed line. is completely blocked and backflow is prevented.

Such a ball-type artificial valve 20 has the following features.

(1) Easy to manufacture and has a small number of parts (only 3 parts). The mold for molding is also simple and inexpensive.

(2) During forward flow, the fluid 17 (for example, blood) flows toward the flow path 22 through the path 26 created between the ball 28 and the main body 20a, but at this time, the ball 28 itself is in point contact with the valve seat 21a. Since there is only enough space, the ball 28 immediately moves toward the valve seat 21b, especially when a backflow occurs, thereby preventing backflow. Therefore, response characteristics are good.

(3) Relatively good durability. For example, in experiments using dogs, there was a track record of driving for 92 days, and an additional 100 days.
There were no problems even after using it repeatedly for more than a day.

However, in the case of such ball-type artificial valves, the following problems still exist, and no effective solutions have been found to date.

(a) As shown in FIG. 8, the inner surface 25 of the main body is curved at a right angle in the passage 26, so large hemodynamic turbulence and eddies occur at this location.
This makes it easier for blood clots to occur.

(b) The blood flow 17 is polarized above and below the ball 28, and these collide with each other on the flow path 22 side, and due to this colliding flow, a uniform flow cannot be formed, which is also a cause of thrombus formation. Become.

(c) Since the valve seat 21a contacts the ball 28 at one location on each side (that is, at only two points), its edges are easily damaged, resulting in poor durability.

C. Purpose of the Invention An object of the present invention is to provide a medical valve device that realizes smooth flow and has excellent durability.

D. Structure of the Invention That is, the present invention provides a medical valve device having a valve seat and a movable valve body, wherein the movable valve body is a spherical body made of an antithrombotic elastomer, and the valve seat is attached to the movable valve body. contact at three or more points, a fluid passage is formed between each of these contact points, and the entire inner surface of the valve body including the valve seat facing this fluid passage is a smooth curved surface along the fluid flow direction. The present invention relates to a medical valve device characterized by a curved shape.

E. Embodiments Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

First, the artificial valve (ball type) according to this embodiment will be explained with reference to FIGS. 1 and 2.

This ball-type artificial valve 30 is also similar to the above-mentioned artificial valve 20.
Similarly, it is formed by bonding two main body parts 30a and 30b, and contains a ball (movable valve body) 28 inside. Both parts 30a and 30b are fixed to each other with an adhesive, but they may also be fitted into one body using a concave-convex fitting method (not shown). Further, each main body part is molded from hard or soft polyvinyl chloride polycarbonate, acrylic, or the like by a known injection molding technique, but it may be sufficient as long as it can be coated with a polyurethane or siloxane antithrombotic agent. The ball 28 is made of antithrombotic elastomer such as silicone resin (or rubber) or polyurethane.

In this artificial valve 30, during the forward flow, the ball 2
The valve seat 31a in contact with the ball 28 is bulged inward at 90° intervals as shown in FIG. ), the distance between the two bulges facing each other at an angle of 180° is made shorter than the diameter of the ball 28.

Therefore, during forward flow, the ball 28 contacts the valve seat 31a at four locations, and four fluid passages 36 are formed between these contact points. Further, the contact points of each valve seat 31a are formed into a smooth curved surface shape as shown in FIG. It is becoming. In addition, in FIG. 1 and FIG. 2B, the ball 28 at the time of reverse flow is shown by a chain line. The surface formed by the valve seat 31b maintains an angle θ with respect to the fluid flow direction, and generally, if this angle θ is within 5°, the generation of vortices and stagnation during forward flow can be sufficiently prevented. The surface of this valve seat 31b is also a smooth curved surface along the fluid flow direction. Furthermore, the inner surfaces of the inlet and outlet sides of the artificial valve 30 are also smooth curved surfaces.

During the forward flow shown by arrow 37, the ball 28 contacts the valve seat 31a at four points, allowing blood to flow from the flow path 24 to the flow path 22, and if blood tries to flow backward in the direction of the arrow 38, the ball 28 contacts the valve seat 31a at four points. immediately valve seat 3
1a and is pressed against the other circular valve seat 31b as shown by the dashed line. In this case, the valve seat 31b
Since the ball 28 is circular and the ball 28 is spherical, they are in close contact over the entire area, and the flow path 24 is completely blocked, thereby preventing blood from flowing backward.

As described above, the artificial valve 30 according to this example has a main body inner surface 3 including the valve seat 31a in the passage 36.
Since the entire number 5 has a smooth curved shape,
The blood flow becomes smooth in the direction of the flow path 22, and vortices and turbulence can be effectively prevented. Moreover, ball 28
Since the valve seat 31a is in contact with the valve at four places,
By increasing the diversion (polarization) of the blood, impinging flows can be reduced and a substantially uniform flow can be created. Furthermore, since the ball 28 is made of an antithrombotic elastomer such as polyurethane, the ball 28
8, blood that comes into contact with the ball does not coagulate on the surface of the ball, and due to the curved shape of the entire inner surface of the main body, it flows very smoothly.

In this way, an artificial valve that does not generate thrombus or can reduce the amount of thrombus is obtained. In addition, since the number of points where the valve seat 31a comes into contact with the ball 28 is increased, the degree of damage to the edges is reduced accordingly, and durability can be improved.

FIG. 3 shows another example of an artificial valve 30, in which the shape of the valve seat 31a is changed and there are three points of contact with the ball 28. Therefore, the same effect as in FIG. 2A can be achieved. The number of contacts is preferably 3 to 12, and even more preferably 4 to 6.

FIG. 4 shows the above artificial valve 30 connected to the connector (7th
13 in the figure), the cannula 12 and the blood conduit 4 are connected on both sides, and the seventh
It is used in the same way as in the figure. When the blood 17 flows in the direction of the arrow, the ball 28 is pressed against the valve seat 31a as described above, and the blood 17 flows through the gap 36.
cannula 1 through passage 22 smoothly.
Flows to 2. In addition, in this example, since the artificial valve also serves as a connector, there is no need to embed the artificial valve in the blood conduit 3 or 4 as in the example of FIG.
Therefore, installation of the artificial valve becomes easy.

FIG. 5 shows an example in which the blood conduit 32 is provided with an artificial valve 30 on the side 4, as in FIG. 7, but the artificial valve is formed as a blood conduit as shown in FIG. If it is integrally molded, attachment of the artificial valve will be relatively easy.

Although the present invention has been illustrated above, the embodiments described above can be further modified based on the technical idea of the present invention.

For example, the structure, shape, size, etc. of the above-mentioned artificial valve may be modified in various ways. The state of contact of the valve seat with the ball and the number of contact points can also be changed. Note that the artificial valve of the present invention may be used in a manner other than that described above.

F. Effects of the Invention As described above, in the present invention, the entire inner surface of the valve body including the valve seat facing the fluid passage between the contact points of the valve seat with respect to the movable valve body is made into a smooth curved surface, so that the fluid flow is smooth. , can effectively prevent vortices and turbulence.
Furthermore, since the valve seat is in contact with the movable valve body at three or more places, by increasing the number of fluid divisions, collision flows can be reduced, and a substantially uniform flow can be formed. Furthermore, since the number of points where the valve seat comes into contact with the movable valve body is increased, the degree of damage to the edges can be reduced accordingly, and durability can be improved. Further, since the movable valve body is made of an antithrombotic elastomer such as polyurethane and is formed into a spherical shape, blood that comes into contact with the movable valve body does not coagulate on its surface and flows very smoothly. In this case, the entire inner surface of the main body has a smooth curved shape, so that blood flows even more smoothly.

[Brief explanation of the drawing]

1 to 5 show embodiments of the present invention, in which FIG. 1 is a sectional view of a ball-type artificial valve, and FIG.
Figure A is a cross-sectional view taken along the line A-A in Figure 1, Figure 2B is a cross-sectional view taken along the line B-B in Figure 1, Figure 3 is a cross-sectional view of a ball-shaped artificial valve according to another example, Figure 4, FIG. 5 is a cross-sectional view showing how the artificial valve is used. 6 and 7 show a conventional example, in which FIG. 6 is a schematic diagram showing the state of use of the blood pump device, and FIG. 7 is an exploded perspective view of the same blood pump device. 8 and 9 show examples of ball-type artificial valves, in which FIG. 8 is a cross-sectional view of the ball-type artificial valve, and FIG. 9 is a cross-sectional view taken along the line -- in FIG. 8. In addition, in the symbols shown in the drawings, 17...Blood, 28...Ball (movable valve body), 30...Artificial valve, 31a, 31b...Valve seat, 35...Inner surface, 3
6...It is a passage.

Claims (1)

[Claims] 1. In a medical valve device having a valve seat and a movable valve body, the movable valve body is a spherical body made of an antithrombotic elastomer, and the valve seat is in contact with the movable valve body at three or more places, and these a fluid passageway is formed between each contact and facing the fluid passageway;
A medical valve device characterized in that the entire inner surface of the valve body including the valve seat is a smooth curved surface along the fluid flow direction.