On the hemodynamics of several prosthetic heart valves: in vitro study.

Distribution of velocity, viscous shear stress and turbulence intensity in the wake of several mechanical heart valves is studied using a laser Doppler anemometer system during steady and pulsatile flow conditions. The corresponding results are also obtained for a sharp-edged orifice which help assess changes in the flow pattern caused by different valve geometries. The results are correlated with the static pressure drop across the valves and its recovery in the wake, as a function of the Reynolds number. Results suggest a substantial increase in turbulence intensity, in some cases by as much as 40- to 50-fold, thus raising a possibility of thromboembolism.