Free emboli formation and procoagulant properties of platelets induced by flow past mechanical heart valves

Numerical studies and in vitro measurements were conducted, aimed at quantifying free emboli formation and procoagulant properties of platelets induced by flow past mechanical heart valves (MHV). Pulsatile turbulent flow simulation was conducted past a St. Jude Medical MHV in the aortic position, to study the effects of valve implantation technique on the thromboembolic potential of the valve. In vitro platelet studies were conducted past the MHV mounted in a recirculation flow loop, by measuring the platelets ability to support the activation of acetylated human prothrombin by factor Xa. The platelet activation state increased monotonically as a function of the recirculation time past the valve, as measured by the thrombin generation rates in the assay.