Hemolysis in Artificial Heart Valves due to High-Level, Short-Duration Laminar Shear Stress

Abstract

In most patients receiving prosthetic heart valves, a mild form of intravascular hemolysis is observed [9]. Usually the degree of hemolysis is well below the maximum rate of r. b. c. production in the red bone marrow, and regular blood transfusions to compensate for erythrocyte loss have been necessary in only exceptional cases [9]. In these patients some kind of malfunction of the artificial heart valve, such as leakage around the valve, has been observed. Over a long period of time, however, even a mild form of intravascular hemolysis may lead to more severe complications. Because of the increased hemoglobin catabolism and the resulting increased bilirubin production, the development of gallstones becomes more likely [7]. Another perhaps more severe problem, which may be particularly important in relation to circulatory assist devices, can arise from the effect of ADP on the clotting system. ATP, which is released from the hemolyzing erythrocyte, can be transformed into ADP and thus enhance the risk of microembolism by increasing platelet adhesion [2].