GB2206182A

GB2206182A - Mechanical heart valve

Info

Publication number: GB2206182A
Application number: GB08711437A
Authority: GB
Inventors: Dr Dhani Ram Baruah; Nirala Baruah
Original assignee: Individual
Current assignee: Individual
Priority date: 1987-05-14
Filing date: 1987-05-14
Publication date: 1988-12-29
Also published as: GB8711437D0

Abstract

A mechanical heart valve comprising three coaxial rings, namely, an inner ring 1, an intermediate ring 2 and an outer ring 3 located one over another, and a pair of semicircular leaflets 5a, 5b eccentrically pivoted in said inner ring, the angular outward swing of said leaflets to open the leaflets being limited to 80 DEG by stops 7 provided in the inner ring 1, said rings and leaflets being made of a biocompetent and fatigue resistant material, preferably zirconium, and said outer ring being provided with a sewing ring 4 made of a biocompetent and durable polymer cloth. <IMAGE>

Description

MECHANICAL HEART VALVE This invention relates to a mechanical heart valve.

Mechanical heart valves are used as replacements for diseased natural aortic, mitral, tricuspid and.pulmonary heart valves. One of the known mechanical heart valves comprises two concentric titanium rings one located over the other and two semicircular pyrolytic carbon leaflets eccentrically pivoted in the inner ring, the angular outward swing of the leaflets with respect to the pivots, that is the opening of the leaflets being limited to a maximum of 700 by stoppers provided in the inner ring, Such a valve also includes a sewing ring made of q biocompetent and durable C polymer cloth such as Wacronleloth and provided on the outer ring. A disadvantage of such a valve is that with time the heart muscles grow into the inner ring thereby restricting the movement of the leaflets.In other words the leaflets will not close or open properly resulting in malfunctioning of the valve. Another disadvantage of such a valve is that since the leaflets are made of pyrolytic carbon they break after some time. Another disadvantage of such a valve is that since the leaflets open only upto a maximum of 700 with respect to the Divots the peripheral openings and the central opening provided by the leaflets are small and the central opening is smaller than the peripheral openings. Consequently flow of blood through the valve will be restricted. Besides this, the peripheral flow will be less than the central flow.This will cause turbulence and thromboembolism. Another disadvantage of such a valve is that the closing of the leaflets produces sharp noise which is audible to the patient and also to peonle nearby probably due to the fact that the leaflets are made of pyrolytic carbon.

This will invariably cause discomfort and fright in the patient and also in the people nearby.

The object of the present invention is to obviate the above disadvantages and provide an improved mechanical heart valve.

According to the present invention there is thus provided a mechanical heart valve comprising three concentric rings, namely, an inner ring, an intermediate ring and an outer ring located one over another, and a pair of semicircular leaflets eccentrically pivoted in said inner ring, the angular outward swing of said leaflets to open the leaflets being limited to 800 by stopners provided in the inner ring, said rings and leaflets being made of a biocompetent and fatigue resistant material, such as zirconium, and said'outer ring being provided with a sewing ring made of a biocompetent and durable polymer cloth, such as gacrontcloth.

An embodiment of the present invention is described hereinbelow with reference to the accompanying drawings, in which Fig. 1 is plan of the improved valve with the leaflets in the closed position; and Fig. 2 is elevation of the valve of Fig. 1 with the leaflets in the open position.

Referring to the drawings, 1, 2 and 3 are three concentric zirconium rings, namely, an inner ring, an intermediate ring and an outer ring respectively. The outer [ A~9 skr ring 3 is provided with a sewing ring 4 of Macronpcloth - 5a and 5b are a pair of semicircular zirconium leaflets eccentrically pivoted in inner ring 1 (pivots are marked 6a and 6b in Fig. 2.). The angular outward swing of the leaflets with respect to the pivots is limited to 800 by stopners 7 provided in inner ring 1 (see Fig.1). The leaflets swing outward to onen the valve (see Fig. 2).Since the leaflets can swing outwardly by 800 the peripheral openings marked 8a and 8b (see Fig.2) and the central opening marked 9 (see Fig.2) provided by the leaflets is almost the same and are comparatively larder. Consequently flow of blood through the central opening and the perioheral openings will be almost the same and comparatively more. The mutually abutting ends of leaflets 5a and 5b are tapered (tapering not marked but can be seen in Fig.2) to ensure smooth and perfect closing of the leaflets.

At the time of implantation, the valve is stitched onto the site of implantation through the sewing ring 4.

The above embodiment is, by way of example, and should not be construed to be limitative of the scope of the present invention.

An advantage of the improved valve is that zirconium being biocompetent and very fatigue resistant the valve does not break or fail and is safe and reliable and has longer life.

Another advantage of the improved valve is that since the peripheral openings and central opening are larger and almost equal the peripheral flow and the central flow are comparatively more and almost equal. Therefore, turbulence and thromboembolism has oeen minimised or eliminated.

Another advantage of the improved valve is that it has been found by us that closing of the leaflets does not produce any audible sharp noise probably because the leaflets are made of zirconium.

Another advantage of the improved valve is that because of the three rings the growth of heart muscles does not reach the inner ring easily quickly. Therefore, the opening and closing of the leaflets is not affected ensuring lonser life of the valve and safe and reliable performance of the valve.

A further advantage of the improved valve is that since the zirconium rings and leaflets are highly negatively charged when they are implanted into the human body, the zirconium repels red blood cells which are also negatively charged. This extensively reduces the thrombogenetic effect of the valve of the preferred embodiment when compared to the known valves.

Claims

CLAIMS:

1. A mechanical heart valve comprising three concentric rings, namely, an inner ring, an intermediate ring and an outer ring located one over another, and a pair of semicircular leaflets eccentrically pivoted in said inner ring, the angular outward swing of said leaflets to open the leaflets being limited to 800 by stoppers provided in the inner ring, said rings and leaflets being made of a biocompetent and fatigue resistant material and said outer ring being provided with a sewing ring made of a biocompetent and durable polymer cloth.

2. A mechanical heart valve according to Claim 1 wherein the rings and leaflets are made of zirconium.

3. A mechanical heart valve according to Claim 1 or Claim 2 wherein CQnrm ) the sewing ring is made of tacronicloth.

4. A mechanical heart valve according to any one of Claims 1 to 3, wherein the mutually abutting ends of said leaflets are tapered.

5. A mechanical heart valve substantially as herein described particularly with reference to the accompanying drawings.