Relative blood damage index of the jellyfish valve and the Bjork-Shiley tilting-disk valve

Determination of the potential for blood cell damage induced by artificial heart valves is essential in deciding the suitability of the valve for clinical use. Both the magnitude and the duration of the shear stress influence the onset and severity of the damage to the constituents of blood. In this study, in vitro shear stress measurements of the mitral jellyfish and Bjork-Shiley tilting-disk (mono) prosthetic valves under physiological pulsatile flow conditions were conducted. The data indicate that elevated levels of shear stress occurred mainly ID downstream from both valves. With the aid of a mathematical model and using the elevated shear stress data, the relative release of hemoglobin by damaged red blood cells and of lactate dehydrogenase by platelets was computed for both valves. For the operating conditions examined, the jellyfish valve was found to cause the least damage to blood, with a relative blood damage index of 0.27 against a value of 0.47 for the Bjork-Shiley valve.