Experimental Investigation of Pulsatile Flow Through Prosthetic Heart Valves

Abstract

Qualitative and quantitative flow visualization study was conducted for the case of a biomimetic pulsatile flow through an artificial heart valve placed into an asymmetric model of an aortic root with sinuses of Valsalva. A prototype trileaflet valve was tested alongside with a tilted disk valve and a bileaflet valve. The study was conducted in test conditions corresponding to 70 beats/min, 5.5 l/min target cardiac output and a mean aortic pressure of 100 mmHg. Flow visualization data obtained using digital particle image velocimetry (PIV) was phase-averaged in order to provide accurate, time-resolved patterns of flow velocity and viscous shear stress values. In the case of the tri-leaflet valve, during systole, a stable jet emanates from the valve, with vortical structures forming on the sides of the jet. These vortical structures entrain the surrounding fluid into the jet, which leads to development of a shear flow instability downstream of the valve. For all considered valve types, a recirculating flow was observed in the sinus area during both the systole and the diastole. No indication of a stagnating flow region was observed, as the fluid was completely washed out from the aortic sinus within each cardiac cycle.