JPH01227754A - Heart artificial valve - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention comprises a cardiac prosthetic valve, in particular a valve ring which pivotally supports at least one valve-like closure body therein, the inner surface of the valve ring being The present invention relates to a cardiac prosthetic valve having a nozzle shape that changes smoothly in the axial direction.

BACKGROUND OF THE INVENTION Natural heart valves are of the tricuspid or bicuspid type, and technically function as check valves that allow blood to flow in one direction while preventing blood from flowing in the opposite direction. When a natural heart valve is replaced with a pendulum-type or ramp-type mechanical prosthesis with a single-cuspid or bicuspid valve inserted, a valve-like obturator in a valve ring sewn and secured at each cardiac ostium. ■It is movable by pressure or blood flow. However, if such a heart prosthetic valve is to be used for a long period of time, there are serious problems such as requiring the patient to take anticoagulants or having to replace the prosthesis for the rest of his or her life. i.e. there is a risk of thrombus formation in the valve ring or closure means;
As a result, the movement of the retaining means and the tightness of the heart prosthesis may be impaired. Additionally, they may grow into body tissues or areas of blood flow.

In heart prosthesis valves of known configuration, particular attention has been paid to the internal pulping surface so as to form a sealing abutment surface for the closure body. In this way, the inner surface of the Halbling is made to have the same shape as the circumferential surface of the closure, and a good sealing sheet that does not require restraint when the closure is in the closed state can be obtained. For this reason, the inner surface of the valve ring is often provided with an abutment or tooling end. British Patent No. 1,447,871 discloses a Halbling having an inner surface with a smoothly changing nozzle shape in the axial direction. The inner surface widens toward the outlet and is configured to join the closed body wing of an aircraft airfoil in an airtight manner with the inner surface. The contour of the inner surface may be hyperboloid, but the inner surface is not rotationally symmetrical. Cardiac prosthetic valves of this type, which consist of a halbling channel extending in the direction of flow, are already at risk from the central region of the inner surface of the flow being disturbed and, as a result, premature vortices forming in the blood flow. Fluid does not flow over long distances as in natural heart valves. The annular vortices created by Halbling create shear stress in the blood, thereby damaging it. Moreover, even in the open state, the cardiac prosthetic valve presents a relatively high fluid resistance caused by the strong contraction of the jet emitted from the ring.

(Object of the Invention) The object of the present invention is to form a cardiac prosthesis comprising a valve ring which pivotably supports at least one valve-like closure body, the inner surface of the valve ring having a nozzle shape that changes smoothly in the axial direction. The purpose of the present invention is to provide a prosthetic heart valve with low fluid resistance and reduced risk of blood damage and thrombus formation.

(Means for Solving the Problems) The present invention solves the above problems by continuously and gradually converging the inner surface of the valve ring in the flow direction over its entire length.

In the cardiac prosthetic valve of the invention, the cross-sectional area of the valve ring decreases continuously in the flow direction, so that the density of the flow curve increases in accordance with the contour of the inner ring surface near the wall. This ensures that the fluid passing through the valve ring is homogeneous and continuous.

Fluid discharge takes place parallel to the longitudinal axis of the valve ring, and the flow is continuous for a considerable length behind the valve ring without a substantial boundary layer. Therefore, the shear stress in the blood flow is reduced to a minimum so that the blood is not damaged. Additionally, by increasing the velocity in the flow direction within the wall boundary layer, the tendency to clot at the Halbling is reduced.

The junction where the closure body connects with the valve ring is a critical area where thrombus formation is likely. Each closure body is supported in the connecting four parts of the Halbling via two outwardly tapering connecting protrusions, each connecting recess being traversed by at least one outflow groove and at both ends of the connecting protrusion. By forming the support, the blood flows in a constant state around the connecting protrusion, so that blood particles are prevented from adhering to the connecting protrusion.The support of the connecting protrusion in the connecting recess is area-wise. rather, it is formed by a dotted or straight contact area exposed to the blood flow. Blood flows through the connection at a relatively high velocity, thereby reducing the risk of fouling.

The invention not only applies to heart prosthetic valves with a single closure body, but also applies well to prostheses with three closure bodies, such as bicuspid valve prostheses or natural heart valves.

Preferably, except for the junction point, the inner surface of the valve ring is a rotationally symmetrical surface so as to form an axially symmetrical flow.

Cardiac prosthetic valves are used not only for the aortic and pulmonary valves, which push blood from the heart into the arterial system, but also for the mitral and tricuspid valves, which return blood from the arteries to the heart.

(Example) Below, the present invention will be explained in more detail using the accompanying drawings.

The prosthetic heart valve of FIG. 1 consists of a valve ring 10 having a substantially circular cross-sectional shape and having a sewing ring 11 around the periphery of the valve ring 10 for fixing the heart valve to body tissue.

In the valve ring 10, the valve-like closure body 12 is supported for pivoting about an axis 13 extending transversely to the ring axis. The shaft 13 is arranged at a distance from the ring shaft, and the closing body 12 has two parts of different sizes separated by the valve shaft 13.
Two wing portions 12a and 12b are formed. By this means, the closure 12 is opened by blood pressure acting in the direction of arrow 14, and closed by backflow blood pressure.

The diameter of the inner surface 10a of the valve ring 10 changes smoothly from the inlet end to the outlet end without twisting.
Oa is flared or curved towards the longitudinal axis of the valve ring. The cross section e of the inlet section and the cross section a of the outlet section are annular. Except for the bearing portion, the inner surface 10a is rotationally symmetrical about the ring axis. At the outlet end of the valve ring 10, the inner surface 10a terminates in a sharp end 10b.

The inner surface 10a constantly decreases in the flow direction and the closure body 1
2 is in the open state, the nozzle groove is formed with a cross-sectional shape that ensures a smooth and substantially swirl-free jet stream.

When A is the surface area of the inlet section e and A is the surface area of the outlet section a, the surface area ratio A'a:Aa is 0.
64 to 0.90.

The corresponding diameter ratio da:de between the outlet diameter d6 and the inlet diameter d is between 0.80 and 095. The ratio of the height h to the outlet diameter d6 is 0.2 to 0.3.

Preferably, the vaulted portion of the inner surface 10a is formed in an arc shape. At the outlet end, the inner surface 10a extends parallel to the ring axis, i.e. at the outlet end the inner surface 10a extends parallel to the ring axis.
The tangent to is parallel to the ring axis.

Due to the shape of the inner surface 10a of said shape, the blood flow in the direction of the arrow 14 is converged within the valve ring 10, while downstream of the valve ring 10 the flow curves run approximately parallel, thus Generates a vortex-free jet flow far enough to the rear of the ring. Premature formation of boundary vortices is avoided by the sharp edge 10b.

2 to 8, one of the two connections provided along the pivot axis 13 of the closure 12 will now be described.

2 extending in opposite directions on the peripheral surface of the closure body 12
Each of the two connecting protrusions 15 is formed in the shape of a spherical cup that protrudes into a connecting recess 16 formed inside the valve ring IO. The connecting recess 16 is laterally delimited by two ridges 17 rising from the inner surface 10a toward the inside of the valve ring, which ridges 17 (seen in the direction of flow) first meet the raindrops 17. form an entrance region where the distance between them is concentrated, i.e. the distance between them decreases, secondly a connection region where the distance between them first increases and then decreases again, and finally an exit region where their mutual distance increases again (the first Figure 2)
. An outflow groove 1 extending substantially in the flow direction between the rain shower parts 17
There are 8. As shown in FIGS. 4 and 7, the diameter of the connecting protrusion 15 is large enough that the protruding part 15 cannot be completely hidden within the connecting recess 16, and the raised portions 17 on both sides of the connecting recess 16 Supported by Therefore, a space is formed between the arc portion of the connecting portion 15 and the connecting recess to allow blood to flow. Each connecting projection 15 joins at only two points in the lateral direction at the ridge 17, while blood is perfused through the outflow groove 18. The blood velocity here is considerably higher, suppressing the possibility of thrombus formation. The converging inlet portion of the outflow groove 18 increases the blood velocity in the connecting recess 16, while
The bifurcated outlet region allows the blood from the outflow channel 18 to be fully integrated again into the main blood flow.

In another embodiment shown in FIGS. 9 to 15, the outflow groove 18 laterally bounded by the bicameral origin 17 consists of an artificial section similar to that in the first embodiment. At its rear, the outflow groove 18 is Y-shaped and forms two branches 18a and 18b.

The connecting recess 16 is surrounded by three ridges 17.17.17a, which form seats or seats for the connecting projection 15 and are placed very close to each other, so that the connecting projection 15 can only penetrate to the bottom of the connecting recess 16. By this means, the connecting protrusion 15
is held in the connecting portion against displacement and can be easily rotated with low frictional force without surface contact with the connecting recess. On the other hand, blood flows around and behind the closure 12 in any state.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal section of the prosthetic valve of the heart, and FIG. 2 is a longitudinal section of the prosthetic valve of FIG. 1 without a closure body to better show the bearing point and outflow groove. 3 is a sectional view taken along line AA in FIG. 2, FIG. 4 is a sectional view taken along line BB in FIG. 2, and FIG. 5 is a sectional view taken along line C-C in FIG. FIG. 6 is a sectional view taken along line D- in FIG.
7 is a sectional view taken along the line EE in FIG. 2, FIG. 8 is a sectional view taken along the line FF in FIG. 2, and FIG. 9 is a sectional view taken along the line FF in FIG. 10 is a longitudinal cross-sectional view of a heart prosthetic valve similar to FIG. 2 with a grooved halbling; FIG. 10 is a cross-sectional view taken along line A-A of FIG. 9; FIG. 12 is a sectional view taken along line C-C in FIG. 9, FIG. 13 is a sectional view taken along line I)-D in FIG. 9, and FIG. 14 is a sectional view taken along line I)-D in FIG. 15 is a sectional view taken along line EE--E, and FIG. 15 is a sectional view taken along line FF--FIG. 9. 10 - Heart prosthetic valve, 10a - Inner surface of the artificial valve, 10b
Sharp end of the artificial valve, 11 Sewing ring, 12 Closing body, 12a and 12b Wings of the closing body, 13 Pivoting axis, 15 Connecting projection, 16 Connecting recess, 17 and 1.7a Protuberance, 18
．． 18a and 18b - outflow groove, a... exit section cross section,
e・Cross section of the inlet. Patent applicant Be. Braun Melzunken Akchen Gesellschaft Representative Patent attorney Aoyama Haka 1 person 0a FIG, 10 FIG, 11 FIG, 12

Claims (5)

[Claims] (1) A cardiac prosthetic valve consisting of a valve ring that rotatably supports at least one valve-like closing body therein, and in which the inner surface of the valve ring has a nozzle shape that changes smoothly in the axial direction. A cardiac prosthetic valve characterized in that an inner surface continuously and gradually converges in the direction of flow over its entire length. (2) The heart prosthetic valve according to claim 1, wherein the valve ring has a sharp end at the outlet end thereof, the inner surface of which allows the valve ring to flow out parallel to the axis of the valve ring. (3) each closure is supported in a connecting recess of the valve ring via two outwardly tapered connecting projections, each connecting recess traversed by at least one outflow groove and connected at both ends thereof; The heart prosthetic valve according to claim 1 or 2, which forms a support for the protrusion. (4) Each outflow groove is defined by both ridges, and the distance between the two ridges in the support area of the connection protrusion is small enough to support the connection protrusion on both ridges, and the connection protrusion and the bottom of the outflow groove The heart prosthetic valve according to claim 3, wherein a space exists between the valves. (5) The cardiac prosthetic valve according to claim 3, wherein the outflow groove forms a Y-shaped branch in the flow direction, and the support region is the branch point.