Numerical prediction of the effect of aortic Left Ventricular Assist Device outflow-graft anastomosis location

摘要

A Left Ventricular Assist Device (LVAD) is used to provide haemodynamic support to patients with critical cardiac failure. As LVADs generate continuous flow to better understand the haemodynamic effects of these devices under different working conditions, and particularly in relation to possible outflow-graft anastomosis location, we performed 3D one-way-coupled fluidstructure-interaction (FSI) for three different LVAD working conditions and with the anastomosis location in the ascending aorta and in the descending aorta. The anatomical model used in this study is a patient-specific geometry reconstructed from computed tomography images and the mechanical support considered is similar to the Jarvik 2000(R) Heart LVAD. Endothelial cells can be influenced by wall stress generated from the blood flow in the artery, so they can produce vascular complications. For this reason, the second aim of this study is to evaluate and analyse, using different mechanical indicators, the wall shear distribution upon the luminal surface of the aorta generated by an LVAD. These numerical investigations demonstrate the utility of one-way-coupled FSI models to compare the haemodynamic conditions for the two LVAD outflow-grafts anastomosis locations and how both affect the aorta and its wall stress. Furthermore, the mechanical indicators allow the identification of wall regions at greater risk of atherosclerosis. The results of this study indicate that an LVAD outflow-graft anastomosis location in the ascending aorta is the optimal configuration.