Combination of acceleration and collision involving the left atrial appendage limbus as a mechanism of hemolytic anemia in the setting of periprosthetic mitral valve regurgitation

Abstract

Hemolytic anemia is a rare, but potentially serious complication of prosthetic heart valves that has been reported in both biologic and mechanical valves inserted in both the aortic and mitral positions. 1-3 Several causal mechanisms of hemolysis have been proposed including shear stress, turbulence, variations in pressure, intrinsic erythrocyte abnormalities, and the interaction of the erythrocyte with the foreign surface of the valve. 4,5 The interaction of these factors results in a complex process whereby the red blood cell (RBC) is destroyed or fragmented. Certain blood flow patterns including acceleration, fragmentation, and collision have been implicated in causing high shear stress on the erythrocyte, resulting in hemolysis. 5 We hereby describe two patients who presented similarly. Both had severe hemolytic anemia, which was shown by transesophageal echocardiography (TEE) to be caused by a combination of acceleration of flow through a discrete periprosthetic mitral regurgitation (MR) jet as a result of a discrete area of valvular dehiscence associated with collision and fragmentation of the periprosthetic jet, as it struck the ridge separating the left pulmonary vein from the left atrial (LA) appendage (the atrial appendage limbus).