Reduction of Vortex Formation in Mechanical Heart Valve during LV Filling

Abstract

Mechanical valve implanted in mitral position has a tremendous effect on the flow dynamics in Left Ventricle (LV). The purpose of this study is to develop a new valve configuration to reduce the vortex ring formation caused by an artificial heart valve in an isovolumetric environment to generate a smoother flow field. Flow Inhibitors (FI) were built on the proximal end of the leaflet of various shapes and sizes to understand their effect on flow dynamics. The test geometries were designed based on the principles of Bernoulli's law of fluid dynamics, pressure staging, and counter disturbance. In this research, equally spaced FI with centralized flow showed a lower and gradual pressure gradient as opposed to the control valve that was used earlier in the study done with a 27mm St. Jude mechanical valve. The pressure gradient dropped gradually from 1.4 Pa to 0.3 Pa as compared to a sudden drop in pressure in the control valve from 1.3 Pa to 0.2 Pa. The velocity value set was 0.8 m/s for simulation which dropped to 0.4 m/s in equally spaced FI centralized flow valve as compared to 0.3 m/s in the control valve. When compared on the basis of smoothness of flow field and gradual drop in the pressure, the former is weighted to be a better design. Flow inhibitor coupled with pressure staging method proved to be effective in enhancing the performance of bileaflet valve.