Evaluation of the Dynamics of a Bileaflet Heart Valve: Physical and Numerical Experiments

Abstract

Clinical reports indicate that mechanical heart valves are still unable to eliminate problems mainly related to a non physiological fluid dynamics like thrombosis and coagulation complications [1]. Advanced experimental technique such as laser doppler anemometry (LDA) and particle image velocimetry (PIV), used to investigate the fluid dynamics of these devices, suffer from some intrinsic limitations (eg. access difficulties, light reflection, low resolution) [2]. In parallel with the increased performance at computing, the use of computational fluid dynamics has gained relevance as a powerful tool able to provide meaningful information of clinical and design aspects [3]. Key parameters in the assessment of blood damage potency (velocity patterns and turbulence, among them) are related to the behaviour of the valve in the flow field. The application of fluid structure interaction (FSI) models moves in the direction of greater accuracy in the reproduction of realistic flow condition in order to reach more in-depth insight into the hemodynamic of the virtual prototypes. The aim of this study is the investigation, in silico, of the bileaflet mechanical valve dynamics during the whole systolic phase. A 3D direct numerical simulation (DNS) was performed and an implicit fluid structure interaction model was used [4,5]. The results of the dynamics of the valve were validated with an experimental counterpart.