Numerical study of hemolysis induced by shear stress at the junction between aorta and ventricular assistance device outflow graft

Ventricular assistance devices (VADs) as the effective treatment for heart failure have been paid high attention from researchers for decades. The follow-up complications such as hemolysis and thrombosis require further optimization for this technique. Shear stress has been demonstrated to be significantly related to the hemolysis because of the rupture of red blood cells membrane with a leaking of hemoglobin in the plasma. This issue has already been commonly investigated inside the pump of VAD, but estimations are still lacking regarding hemolysis generation in the aorta itself after VAD implantaion. Thus, the present study aims to evaluate the hemolysis in aorta through establishing the 3D numerical model of aorta with left ventricular assistance device (LVAD). Non-Newtonian Carreau model has been adopted to predict the blood rheology. Comparisons of hemolysis evaluation have been made with two different mathematical models. Moreover, the flow topology and hemodynamic variations have been studied. Two different working conditions of LVAD have been considered corresponding to different heart failure severities. The results reveal a relatively low level of hemolysis risks in aorta. The thrombosis is more prone to occur in the case of severe heart failure condition.