Heart valve prosthesis

Claim 1

A heart valve prosthesis comprising an annular frame, a disc-shaped obturator, and means for coupling the obturator to the annular frame which allow the obturator to rotate around its central axis and to orient itself about one of its chordal axes, under the action of the blood flow, between an open angular position and a closed angular position so as to allow the free flow of blood through the aperture of the annular frame in one direction and the interruption of the flow in the opposite direction, respectively, wherein said coupling means are such as to enable the obturator to orient itself perpendicular to the plane of the frame in the open angular position, and the side of the obturator which faces away from the central axis of the annular frame in the open angular position is defined, at least over a major portion of its peripheral part, by a surface which is generated by rotation about the central axis of the obturator, of a curve, the locus of centres of curvature of which lies at a finite distance on the opposite side of said curve from a curve which generates, by rotation about said central axis of the obturator, a surface defining the other side of the obturator, whereby, when the obturator is in the open angular position, blood flowing through the aperture of the annular frame is smoothly deflected over and around the obturator.