“Thrombosis and cardiovascular risk in devices, CVS pathologies, and due to smoking”
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Abstract: Cardiovascular devices expose recipients to enhanced risk of thrombosis and cardioembolic stroke. In most cases anticoagulation regimen is mandated for these patients, that does not eliminate the risk. Thrombus formation in prosthetic cardiovascular devices and in arterial pathologies is associated with elevated hemodynamic stresses that may induce platelet activation, thrombus formation, and potentiate their interaction with the endothelium. In vitro studies were conducted to estimate the thrombogenic potential of various Prosthetic Heart Valve (PHV) designs. A new polymer trileaflet design was tested for its thrombogenic potential and compared to that of existing prosthetic heart valves (PHVs) routinely implanted in patients: a St. Jude Medical bileaflet mechanical heart valve (MHV) and a St. Jude porcine bioprosthetic tissue valve. The valves were mounted in a left ventricular assist device (LVAD) and the procoagulant activity of the platelets was measured using an innovative platelet activation state (PAS) assay. Complementary in vivo studies were conducted in the sheep model to study the effects of valve implantation on platelet activity and the risk of cardioembolic stroke. Sheep with implanted valves had increased level of platelet activity, as measured with the PAS assay. Transcranial Doppler measurements indicated a significant increase in the amount of microembolic signals, as measured in the carotid artery of the sheep after valve implantation.