Platelet Activation and Procoagulant Evaluation in an in vitro System

Thromboembolic events caused by implantedcardiovascular devices present serious challenges tosurgeons and researchers alike. In particularbileaflet mechanical heart valves are prone tothrombus formation in the hinge region due to acombination of high shear stress and stagnationregions. It is desirable to study this phenomenon ina more physiological environment. This researchpresents models that isolate and mimic bileafletmechanical heart valve (BMHV) hinge geometries toquantitatively characterize procoagulant potential ina novel in vitro blood flow system. These resultswere correlated with digital particle imagevelocimetry measurements detailing flow fields forthe same models. Simple round and slit orifices wereused to model the hinge region and B-datum linerespectively of BMHVs. Channels that approximatedthe different geometries of various BMHV hingedesigns were also developed and evaluated. As a finaltest BMHVs were also studied using these sametechniques to assess the influence on hinge gap widthand hinge geometry on platelet activation andprocoagulant potential.