Blood Damage Induced by Cardiovascular Devices: High Resolution Measurements in a Scaled-Up Model Valve

In this paper we describe the use of a scaled-up mechanical heart valve (MHV) model to measure flow at very high resolution and assess blood damage potential. A major goal in MHV design is to reduce the risk of mechanically induced thrombosis and hemolysis. Blood damage is triggered at the cellular level by several phenomena, including prolonged exposure to high shear stress and long residence in zones of flow recirculation [1] as well as turbulence [2]. To enhance the capability to understand and predict blood damage, it is necessary to comprehend the structure of the flow field at very small scales. Particle Image Velocimetry (PIV) has been used extensively to measure the flow field in MHVs [3]. However, the spatial resolution (defined as the distance between velocity measurement locations) of current PIV systems is coarse with respect to cellular scale. Temporal resolution can be increased to capture rapidly evolving transient features, but the price to pay is even poorer spatial resolution [4].