Prosthesis (i.e. – artificial body members) – parts thereof – or ai – Heart valve – Having rigid or semirigid pivoting occluder
Reexamination Certificate
2000-05-25
2002-08-13
Prebilic, Paul B. (Department: 3738)
Prosthesis (i.e., artificial body members), parts thereof, or ai
Heart valve
Having rigid or semirigid pivoting occluder
C137S512100, C137S527000, C137S535000
Reexamination Certificate
active
06432135
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to fluid check valves, and, more specifically, to implantable heart valves that work in blood. Many heart valves in use today use rigid components because they last a long time with high mechanical reliability as opposed to pig valves which have limited life. A disadvantage in rigid valve technology even with the most hemocompatible materials, like carbon and titanium, is the problem of washing out the bearing pivots with fresh blood.
Typical pivots employ a male pin combined with a female socket machined into the housing of the valve. The pivot allows the leaflet to rotate in the housing either opening or closing the valve passageway. Since the female socket is counterbored into the wall of the housing, into which the male pivot sits, it is difficult to hydrodynamically flush out the bearing continuously with fresh blood. This inherent deficiency has existed in valve designs for decades.
The present invention eliminates these pivots and the associated washout problem. Without sufficient bearing washout, anti-coagulants must be taken by the patient to avoid clotting and thrombosis in the valve. Because this problem is eliminated in the present design, it may be possible to eliminate anti-coagulant therapy. This is a major advantage.
Another object of the present invention is to eliminate contact and wear as exists in pivot bearings for the leaflet. Hard ceramic carbon is used in existing valves not only because of its blood chemical compatibility, but because it is wear resistant to last for many years. The internal stops in the pivots are highly loaded so a wear resistant bearing surface is required.
In the instant invention, since no contact occurs in the bearing, highly wear resistant materials are not required. This allows the use of new and better valve materials in the future that are even more thrombo-resistant.
Another object of the invention is to eliminate stringent machining tolerances in the bearing parts. Conventional pivot bearing tolerances are so stringent that selective assembly of parts is employed to achieve the best fit possible. The present torsion wire suspension should not require such tight tolerances.
Accordingly, it is desired to provide a suspension for a leaf valve for eliminating bearing contact.
BRIEF SUMMARY OF THE INVENTION
A valve includes a housing, a valve leaflet disposed therein, and a torsion wire fixedly suspending the leaflet to the housing for pivotal reciprocation therein. Pivot bearings are thusly eliminated for supporting the valve leaflet, and when used as a prosthetic heart valve corresponding blood damage is also eliminated.
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Conte Francis L.
International Business Machines - Corporation
Matthews William H.
Prebilic Paul B.
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