Study of Leaflet Radial Curve Effect on Polymeric Valve Performance By Finite Element Method

Geometries of leaflets play an important role in designing prosthetic valves (PVs). A valve must have a high geometric orifice area (GOA) and low regurgitation to function properly. In this paper, some polymeric tri-leaflet valves were designed based on radial and free edge curves of previous designs and together with them a new radial curve, which consists of two lines and an arc between them was proposed. Mechanical properties of polystyrene polymer are assigned to leaflets using the Mooney-Rivlin hyperelastic model. The finite element method (FEM) has been utilized to evaluate GOA, regurgitation, von Mises stress, and leaflets' coaptation in a fully closed and opened state. Results were compared, and the valve with the proposed leaflet geometry exhibited better performance among all valves. 69.1% GOA, 2.6 mm coaptation width, 0.921 MPa von Mises stress for closed-form, and 0.731 MPa von Mises stress for opened form were recorded. The significance of the radial curve in designing the geometry of leaflets has been revealed especially on the case of leaflets' coaptation. The more this curve tends to a straight line the higher the geometric orifice area and the weaker the coaptation. The proposed curve establishes an equilibrium between these two parameters.