First significant animal survival with a Wankel-type left ventricular assist device

The authors' laboratory is developing a device for heterotopic left ventricular assistance. It consists of a titanium Wankel-type rotary pump, driven by an hermetically sealed electric motor. In our animal experiments, the motor-pump unit was implanted in the thoracic wall. The pump was connected to the left heart chambers by left atrial cannulation, and to the descending aorta. The motor was connected to the power and control unit by an electric wire through the skin. In this report, the authors describe the first significant animal survival with this system. Laboratory results were encouraging for hemolysis. The pump failed at 13 days due to a deposit of fibrin and blood cells in the gear housing. This problem was not surprising since similar events have been encountered with centrifugal devices. However, further design improvements should allow longer animal survival and clinical application.