Anh V Nguyen
University of Rome Tor Vergata, Italy
Title: Hemodynamics and hemolysis of blood flow through mechanical aortic heart valves: A numerical study
Biography
Biography: Anh V Nguyen
Abstract
Statement of the Problem: The purpose of this research is to numerically investigate blood flows over an aortic bileaflet mechanical heart valve employed in the human heart through valve implantation surgery. The modeled valve used in the simulation is a St. Jude Medical valve with three sinuses Valsava grafts (Fig. (a)). Many previous studies of bileaflet mechanical heart valves have been done but there is still lack in investigations of hemolysis of the blood at the closure of the valve leaflets as well as at the highly turbulent flows due to high viscous shear stresses of the flow in the ascending aorta.
Methodology & Theoretical Orientation: The computational method is a fluid-structure integration (FSI) algorithm that couples direct numerical simulation (DNS) and immersed boundary method (IBM). The FSI model is used to model blood flow through the aortic valve to investigate physiological characteristics of the blood flow in silico. Boundary conditions and flow geometry are set with the same physiological condition as the real model of the prosthetic heart valve that is used in reality (Fig. (b)).
Findings: Physical parameters of hemodynamics in the aortic prosthesis in a number of cardiac cycles were obtained. The results indicate that there are strong turbulences occurring in the flow field downstream after the heart valve (Fig. (c)), especially in the sinuses of Valsava. Hemolysis takes place frequently in the trailing edges of the leaflets that affects quality of blood pumping into the ascending aorta.
Conclusion & Significance: Shear-induced effects play an important role in blood damage as well as platelets damage in the systolic phase of cardiac cycle. The closing phase of cardiac cycle also generates blood damage at the trailing edges of the leaflets as well as at the hinge regions of the leaflets.