JP2780977B2 - Artificial heart valve - Google Patents

Description

The present invention relates to a prosthetic heart valve, and more particularly, to a prosthetic heart valve having a valve ring, wherein at least one closing valve element is pivotally supported inside the valve ring and the valve ring is supported. The present invention relates to a prosthetic heart valve in which a nozzle portion in which a cross-sectional shape of an inner surface portion of a valve ring smoothly changes along a longitudinal axis is formed.

(PRIOR ART) Natural heart valves are of the tricuspid or bicuspid type,
Technically speaking, it functions as a check valve that allows blood to flow in one direction while preventing backflow. When a natural heart valve is replaced with a pendulum-type or inclined-plate-type mechanical prosthesis into which a one-cuspid or two-cuspid valve is inserted, the valve-like closure in a valve ring sewn and fixed to each heart orifice becomes blood pressure. Or it is made movable by blood flow. However, long-term use of such an artificial heart valve has serious problems, such as imposing a patient on taking an anticoagulant or replacing the prosthesis (artificial heart valve) for a lifetime. That is, there is a risk that a thrombus may form in the retaining means of the valve ring or closure, which may impair the movement of the retaining means and the tightness of the prosthetic heart valve. In addition, body tissue may grow in the blood flow area.

In known shaped prosthetic heart valves, special attention has been paid to the inner surface of the valve ring so as to form a sealing connection surface to the closure valve body. Therefore, the inner surface of the valve ring has the same shape as the peripheral shape of the closing valve body, and when the closing valve body is closed, a good sealing seat is secured without requiring any restraining means. For this reason, the inner surface of the valve ring is often provided with an abutment or sealing end. GB 1447871 discloses a valve ring having an inner surface whose nozzle shape changes smoothly in the axial direction. The inner surface widens toward the outlet and is configured such that the airfoil-shaped closing valve body is in airtight contact with the inner surface of the valve ring. Although the inner surface of the valve ring has a hyperbolic shape, the inner surface is not rotationally symmetric. This type of prosthetic heart valve, which consists of a valve ring channel extending in the direction of flow, already has a turbulent flow from the central area of the inner surface,
As a result, there was a high risk that vortices would form early in the blood stream. Fluid does not flow over long distances as in natural heart valves. The annular vortex created by the valve ring creates shear stress in the blood, which damages the blood. Furthermore, also in the open state, the prosthetic heart valve has a relatively high flow resistance due to the strong atrophy of the jet emitted from the ring.

(Object of the Invention) An object of the present invention is to provide a valve ring, wherein at least one closing valve body is pivotably supported inside the valve ring, and a cross-sectional shape of an inner surface portion of the valve ring is along a longitudinal axis. It is an object of the present invention to provide a prosthetic heart valve which has a nozzle portion which changes smoothly and smoothly, has low fluid resistance, and reduces the risk of blood damage and thrombus formation.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides a method in which the inner surface portion of the above-mentioned valve ring is smoothly and continuously formed in a radial direction along a longitudinal axis of the above-mentioned valve ring. By forming the nozzle portion defined by the inner surface portion of the valve ring so as to gradually and continuously converge over the entire length thereof in the flow direction of the fluid flowing therethrough by making the shape of the curved surface smaller, A support portion for supporting the closing valve body so as to be pivotable is formed in an inner region on an inner surface portion of the second embodiment.

In the prosthetic heart valve of the present invention, the cross-sectional area of the valve ring is continuously reduced in the flow direction, so that the streamline density of the fluid flowing near the wall and following the contour of the inner ring surface is increased. This ensures that the fluid passing through the valve ring is homogeneous and continuous. The discharge fluid flow is parallel to the longitudinal axis of the valve ring, and the fluid flow is substantially continuous without substantial boundary vortices over a considerable length behind the valve ring. In this way, the shear forces in the blood stream are reduced to a minimum, preventing blood damage. Furthermore, by increasing the fluid flow velocity in the direction of flow in the inner wall boundary layer of the valve ring, the risk of thrombus formation in the valve ring is reduced.

The joint where the closing valve body is connected to the valve ring is an area where the risk of forming a thrombus is high. Therefore, at both ends of the closing valve body, there are provided joint projections which become gradually thinner outward, and these joint projections are supported by two joint recesses formed in an inner region of the inner surface of the valve ring. At least one transverse outflow channel is provided in the recess and support portions for supporting the joint protrusion are provided on both sides of the outflow channel, whereby blood flows in a constant state around the joint protrusion, and as a result, blood Particles can be prevented from adhering to the joint protrusion. The support part of the joint protrusion in the joint recess is not a surface contact part but a point or line contact part for the blood flow. Blood flows through the support at a relatively high velocity, thereby reducing the risk of adhesion.

The invention can be applied not only to prosthetic heart valves having a single closure but also to prostheses with three closures, such as a bicuspid valve prosthesis or a natural heart valve.

Preferably, the inner surface of the valve ring except for the joint portion has a rotationally symmetric surface so as to form an axisymmetric flow.

The prosthetic heart valve of the present invention can be used not only for aortic and pulmonary valves that pump blood from the heart to the arterial system, but also for mitral and tricuspid valves that return blood from the arteries to the heart. it can.

(Example) Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

The prosthetic heart valve of FIG. 1 comprises a valve ring 10 having a substantially circular cross-sectional shape, and a sewing ring 11 around the valve ring 10 for fixing the heart valve to body tissue. In the valve ring 10, the closing valve body 12 is pivotally supported about a pivot axis 13 extending in a direction transverse to the longitudinal axis of the valve ring. The turning shaft 13 is arranged at a distance from the longitudinal axis of the valve ring 10. The closing valve body 12 has two wing portions 12a and 12b having different dimensions, which are divided by a pivot shaft 13.
Is formed. In this way, the closing valve body 12
Is set to the open position by the blood pressure acting in the direction, and closed by the backflow blood pressure.

The diameter of the inner surface 10a of the valve ring 10 changes smoothly without kinking from the inlet end to the outlet end.
10a is curved so as to project toward the longitudinal axis of the valve ring 10, and has an arch shape. The cross-sectional shape of the inlet end e and the outlet end a of the valve ring 10 is circular. The inner surface 10a of the valve ring 10 excluding the joint portion is the valve ring 1
It is rotationally symmetric about the longitudinal axis of zero. At the outlet end a of the valve ring 10, the inner surface 10a ends at an acute edge 10b. The cross-sectional shape of the inner surface portion 10a decreases at a constant rate along the flow direction, and forms a nozzle portion that generates a smooth and almost vortex-free discharge flow when the closing valve body 12 is in the open state.

If the size of the cross section of the inlet end e of the valve ring 10 is Ae and the size of the cross section of the outlet end a is Aa, the area ratio
A _a : A _e is 0.64 to 0.90.

Diameter da of outlet end _a and inlet end e of valve ring 10
Diameter ratio d _a between the diameter d _e of: d _e is a 0.80 to 0.95. The ratio of the height h to the diameter d _a of the outlet end a is a 0.2 to 0.3.

An arcuate vault is formed on the inner surface 10a of the valve ring 10. The inner surface 10a extends parallel to the longitudinal axis of the valve ring 10 at the outlet end a, that is, the inner surface 10a
The tangent at outlet end a of a is parallel to the longitudinal axis of the valve ring.

By forming the inner surface portion 10a of the valve ring 10 into the above shape, the blood flow flowing in the direction of the arrow 14 inside the valve ring 10 is converged, while the respective flow curves in the downstream portion of the valve ring 10 are mutually different. It extends substantially parallel and thus produces a swirl-free discharge flow from the valve ring 10 all the way to the rear. The sharp edge 10b of the valve ring 10 prevents early formation of boundary vortices.

2 to 8 together with the pivot axis of the closing valve body 12
One of the two joints provided at both ends along 13 will be described below.

Two spherical cup-shaped joint protrusions 15 extending in opposite directions to the peripheral surface of the closing valve body 12 are inserted into corresponding joint recesses 16 formed on the inner surface 10a of the valve ring 10, respectively. The joint recess 16 is laterally defined by two raised portions 17 rising from the inner surface 10a of the valve ring 10. When viewed in the direction of flow, these ridges 17
17 converges, i.e. the entrance area in which the distance between the ridges decreases, then the connection area in which the distance between the ridges first increases and then decreases again, and finally the connection area It forms an exit area in which the distance between the parts increases again (FIG. 2). An outflow channel 18 extending substantially along the flow direction is formed between the ridges 17. As shown in FIGS. 4 and 7, the diameter of the joint protrusion 15 is set to a size that cannot completely cover the joint protrusion within the joint recess 16. Supported. in this case,
A gap is formed between the arcuate portion of the joint protrusion 15 and the bottom surface between the two raised portions 17 of the joint recess 16, and blood is circulated through the gap. The joint protrusion 15 is provided on the raised portions 17 on both sides.
The blood is perfused through the outflow channel 18 between the ridges 17 while making point-to-point contact. Here, the flow rate of the blood is set to be considerably high, and the formation of a thrombus is suppressed. The converging inlet of the outflow passage 18 increases the flow velocity of the blood flow in the joint recess 16, while the blood flow diverted by the branch flow passage formed in the joint recess 16 returns to the outlet of the outflow passage 18. The region is completely integrated as the main blood flow.

In another embodiment shown in FIGS. 9 to 15, an inlet of an outflow passage 18 whose width is limited by both raised portions 17 is formed in the same manner as in the first embodiment. Outflow channel 18
A Y-shaped branch channel portion formed of two branch portions 18a and 18b is formed behind the inlet portion. Joint recess 16 has three raised parts
A space surrounded by 17, 17, 17a is formed, these three ridges being arranged so close to each other that the joint projections 15 do not completely sink into the bottom of the joint recess 16; A seat for receiving the projection 15 is formed. With this configuration, the joint protrusion 15 is not displaced,
It is held in the joint recess 16 and can be easily rotated with low frictional force without surface contact with the joint recess 16. On the other hand, regardless of whether the closing valve body 12 is in the closed or open state, the blood flows around and behind the closing valve body.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of the prosthetic heart valve of the present invention, and FIG. 2 omits the illustration of a closing valve body to better show an outflow path at a joint portion in the prosthetic heart valve of FIG.
FIG. 3 is a longitudinal sectional view of the artificial heart valve, FIG. 3 is a sectional view taken along line AA of FIG. 2, FIG. 4 is a sectional view taken along line BB of FIG. 2, and FIG. FIG. 6 is a sectional view taken along line CC of FIG. 2, FIG. 6 is a sectional view taken along line DD of FIG. 2, FIG. 7 is a sectional view taken along line EE of FIG. FIG. 9 is a sectional view taken along line FF of FIG. 2; FIG. 9 is another embodiment of the present invention, similar to FIG. 2 having a deformed joint portion and a valve ring forming a Y-shaped branch outflow passage; 10 is a longitudinal sectional view of the artificial heart valve, FIG. 10 is a sectional view taken along line AA in FIG. 9, FIG. 11 is a sectional view taken along line BB in FIG. 9, and FIG. 9 is a sectional view taken along line CC of FIG. 9, FIG. 13 is a sectional view taken along line DD of FIG. 9, FIG. 14 is a sectional view taken along line EE of FIG. 9, and FIG. FIG. 10 is a sectional view taken along line FF of FIG. 9; 10 ... valve ring, 10a ... inner surface of valve ring, 10b ... acute angle end formed at outlet end of valve ring, 11 ... sewing ring, 12 ... closing valve body, 12a and 12b ... Wing part of closing valve body, 13… rotating shaft, 15… joint protrusion, 16…
Joint recessed portions, 17 and 17a ... ridges, 18, 18a and 18b ...
Outflow channel, a ... outlet end of valve ring, e ... inlet end of valve ring.

Continuation of the front page (72) Inventor Günter Lau 5100 Archen, Fuchselde No. 50 (56) References JP-A-57-99953 (JP, A) JP-A-61-85940 (JP, A) JP 56-23944 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) A61F 2/24

Claims (5)

(57) [Claims] 1. A valve ring (10) having an inner surface portion (10a) defining a nozzle portion extending along a longitudinal axis and having at least one nozzle inside the valve ring (10). In a prosthetic heart valve configured to pivotally support two closing valve bodies (12), an inner surface (10a) of the valve ring (10) is arranged along a longitudinal axis of the valve ring (10). By having a curved surface shape whose size in the radial direction is smoothly and continuously reduced, the nozzle portion defined by the inner surface portion (10a) of the valve ring (10) is moved in the flow direction of the fluid flowing therethrough. And a support portion for pivotally supporting the closing valve body (12) in an inner region of the inner surface portion (10a) of the valve ring (10) while being formed so as to converge continuously over the entire length. (16, 17) And wherein,
Artificial heart valve. 2. The valve ring (10) has an inlet end (e) and an outlet end (a), and the outlet end (a) of the valve ring (10) has the valve ring (10). The fluid flowing through the valve ring (10) generates a fluid flow parallel to the longitudinal axis of the valve ring (10) such that the inner surface portion (10a) forms an acute edge. 2. The artificial heart valve according to claim 1. 3. A joint projection (15), which becomes gradually thinner outward, is provided at each end of the closing valve body (12), and these joint projections (15) are connected to the inner surface (10a) of the valve ring (10). Are supported by two joint recesses (16) formed in the inner region of
At least one transverse outflow channel (1
3. The artificial heart valve according to claim 1, further comprising: a support portion for supporting the joint projection on both sides of the outflow channel. 4. An outflow channel (18) on each side of a transverse outflow channel (18).
And a support portion for fitting a pair of joint protrusions (15) provided on each closing valve body (12) between the two protrusions (17) is formed. 4. The artificial heart valve according to claim 3, wherein a gap exists between the joint protrusion (15) and the bottom of the transverse outflow channel (18) at each of the support portions. 5. In the flow direction, a Y is provided in the transverse outflow channel (18).
The artificial heart valve according to claim 3, further comprising: a Y-shaped branch flow path portion; and a support portion for supporting the joint protrusion (15) in the Y-shaped branch flow path portion.