Abstract: Bi-leaflet heart valves have improved flow characteristics in their open position as a result of employing valve bodies of elongated axial dimension. By elongating the axial dimension of valve bodies which have straight, smooth interior wall surfaces oriented parallel to the centerline through the valve and to the flow path of blood, and by employing a pair of occluders which have major surfaces that are rectilinear and can assume an orientation that is substantially parallel to the centerline in the open position, a streamlining of blood flow occurs. The pivot arrangements avoid the use of acute angular surface orientations and cause the occluders, although aligned substantially parallel to blood flow in the open position, to promptly pivot toward the closed position upon reversal of blood flow. This streamlining substantially reduces turbulence and results in low head loss, both significant advantages in bi-leaflet heart valve performance.

Abstract: A device to provide access to the circulatory system of a living body for simultaneous withdrawal and return of blood to the system includes a tubular conduit and a housing integrally associated with the conduit and having fluid communication therewith through at least one aperture in the conduit wall located at the point where the conduit adjoins the housing. The relation between the housing and the conduit is such that the axes of both intersect at right angles. The housing extends the fluid communication to a point outside the living body. Inside the housing is a movable valve body which has a pair of ports alignable with the aperture. The valve body is movable in the housing between positions of alignment and nonalignment of the apertures and the port to selectively establish fluid communication between the circulatory system and the outside of the living body.