Platelet Activation and Procoagulant Evaluation in an in vitro System

Thromboembolic events caused by implanted cardiovascular devices present serious challenges to surgeons and researchers alike. In particular bileaflet mechanical heart valves are prone to thrombus formation in the hinge region due to a combination of high shear stress and stagnation regions. It is desirable to study this phenomenon in a more physiological environment. This research presents models that isolate and mimic bileaflet mechanical heart valve (BMHV) hinge geometries to quantitatively characterize procoagulant potential in a novel in vitro blood flow system. These results were correlated with digital particle image velocimetry measurements detailing flow fields for the same models. Simple round and slit orifices were used to model the hinge region and B-datum line, respectively, of BMHVs. Channels that approximated the different geometries of various BMHV hinge designs were also developed and evaluated. As a final test, BMHVs were also studied using these same techniques to assess the influence on hinge gap width and hinge geometry on platelet activation and procoagulant potential.