Recent experience with the Baylor left ventricular bypass pump.

The current Baylor left ventricular bypass pump is a pneumatically actuated diaphragm pump lined with segmented polyurethane. It is a swirl design in which blood moves in a circular motion within the pump. It has tilting disc inflow and outflow valves and the stroke volume is 60 ml. It is intended for periods of use up to fourteen days. Eighteen devices have been implanted in normal calves. The mean duration of pump operation was eleven days. The pump-canula junctions and regions of the valve seats have been sites of thrombus formation and are being redesigned to eliminate areas of flow separation and stasis.