A Fluid Structure Interaction Model of Native Aortic Valve with Physiologic Blood Pressure and Tissue Properties

The kinematics and dynamics of the aortic valve (AV) are highly dependent on the combined mechanical properties of the valve and the aortic root (AR), as well as the blood flow. Previous numerical models of physiological AV and AR, that included coaptation under the full cardiac cycle, ignored the influence of the blood flow (performing “dry” simulations). This study presents a full fluid-structure interaction (FSI) model of healthy porcine AV and AR. The FSI simulations are based on coupled structural and fluid dynamics solvers that allow accurate modelling of the pressure load on both the AR and the leaflets. The partitioned solver has non-conformal meshes and the flow is modelled employing the Eulerian approach. The leaflet tissue model recognizes the hyperelastic collagen fibre network embedded in the elastin matrix. The tissues of aortic sinuses are also deformable and have hyperelastic behaviour. The coaptation is modelled with master-slave contact algorithm. A full cardiac cycle is modelled by imposing physiological blood pressure at the upstream and downstream boundaries. The kinematics of the AV is compared with previously published measurements of porcine AV in a pulsatile loop. Detailed analysis of the resulting flow field and stress distribution, as well as derived geometric quantities (such as coaptation details) allow realistic simulations and improved the comprehension of the kinematics and dynamics of AV.