Blood flow dynamics through a defective mechanical heart valve.

摘要

A model of asymmetrical 2-D defective bileaflet mechanical heart valve was used to simulate steady and pulsatile blood flow through a defective mechanical heart valve under several flow and malfunction severity conditions. The calculations used Reynolds-averaged Navier-Stokes equations with Newtonian blood properties. The results showed that the flow upstream and downstream of the defective valve is highly influenced by malfunction severity and this resulted in a misleading improvement in the correlation between simulated Doppler echocardiographic and catheter transvalvular pressure gradients. In this study, two potential non-invasive parameters were proposed using Doppler echocardiography and phase contrast magnetic resonance imaging, for an early detection of mechanical heart valve malfunction. Finally, the relation between the coherent structures downstream of the valve and the valve malfunction was shown and the significant impact of valve malfunction on platelet activation and as a consequence, on thrombus formation was also shown.