Abstract: The prosthesis is manufactured by knitting a foundation yarn with a high degree of heat-shrinkability and at least one effect yarn which is substantially heat stable, immersing the resulting fabric in boiling water so as to shrink the foundation yarn and thereby reduce its permeability to liquids while not affecting the effect yarn significantly so that it is possible to obtain good velvet effects without resorting to very high overfeed rates for the effect yarn.

Abstract: The thickness of the obturator (3) increases gradually from the central region (C.sub.9 C.sub.10) towards the ends (P.sub.9, P.sub.10) of the edge (6) nearest to the axis of articulation (5) to the prosthesis, and decreases gradually or is constant from that edge to the other end edge (7) which forms the outer edge of the obturator.

Abstract: In a prosthetic heart valve comprising a generally annular stent and at least two obturators mounted in the stent so as to be above to pivot between an open position and a closed position, the stent is provided with at least one element which projects inwardly of the stent itself, while each of the obturators has recesses which cooperate with the projecting element of the stent with clearance in a generally-hinged configuration which enables the obturators to pivot between the open position and the closed position.

Abstract: A cardiac valve prosthesis comprises an annular frame and a valve sleeve with a plurality of valve flaps which are forced apart by the blood passing through the prosthesis in one direction and which are mutually coapted by blood flow in the opposite direction. The frame of the prosthesis includes a rigid or semi-rigid stent constituted by a tubular body with a ring of apertures and with first and second end edges which, in the implanted position of the prosthesis, are respectively upstream and downstream with respect to the direction of flow of the blood through the prosthesis. Biocompatible textile completely covers the rigid stent: the covering has associated suture stitches some of which extend through the apertures of the said ring to attach the covering to the stent itself.

Abstract: The prosthesis comprises an annular frame and a disc-shaped obturator which is coupled to the frame and is pivotable, under the action of the blood flow, between an open annular position and a closed angular position, so as to allow the flow of blood through the aperture of the annular frame in one direction and the interruption of the flow in the opposite direction, respectively. The obturator is coupled to the frame in such a way that, in the open position, it may orient itself in a direction substantially perpendicular to the plane of the frame. 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 in its peripheral part, by a surface which is generated by the rotation, about the central axis of the obturator, of a curve the locus of the centers of curvature of which lies on the opposite side of this curve from a curve which generates, by rotation around the central axis, a surface defining the other side of the obturator.