Taub Laboratories for Mechanical Circulatory Support continue as an interdisciplinary group engaged in design, manufacture, and in vitro evaluation of new circulatory support devices and their evaluation in experimental animals. Emphasis is on development of paracorporeal left ventricular assist devices to partially assist a failing left ventricle of the heart to pump blood for a period of two weeks. The assist devices which use segmented polyurethane as the blood contact material, are of a swirl design to minimize flow stasis, and have utilized Lillehei-Kaster tilting disc prosthetic valves. The potential use of cultured endothelial cells on biomaterials to try to provide the nonthrombogenic lining characteristic of natural blood vessels is being explored. Evaluation of left ventricular assist devices is carried out in normal experimental animals, but an effort is underway to produce a stable left ventricular failure model in experimental animals, in which to test the therapeutic use of the assist devices. In the 08 year, the Left Ventricular Bypass Pump will be redesigned to eliminate steps in the flow pathway, to optimize the location of the tilting disc inflow valve, and to improve outflow characteristics by using a ball valve in that position. As the left ventricular failure model progresses, pilot studies will be begun to assess the efficacy of the assist device in the presence of left ventricular failure. Detailed assessment will be made of the effect of the assist devices on delicate blood clotting systems. Data management is being reassessed and improved. BIBLIOGRAPHIC REFERENCES: Noon, G.P., DeBakey, M.E., and Norman, N.A., "Left heart bypass as practiced at Baylor College of Medicine", The Surgical Team, 5: 36-38, 1976. Holloway, G.A., Jr., Daly, C.H., Kennedy, D., and Chimoskey, J.E., "Effects of external pressure loading on human skin blood flow measured by 133Xe clearance", J. Applied Physiology, 40: 597-600, 1976.