A Left Ventricular Assist Device (LVAD) is a battery-powered mechanical pump that acts as a bridge between the apex of the heart and the aorta and is required by patients who have advanced heart failure. However, some individuals may develop aortic valve regurgitation (AR) following LVAD surgical implantation. An MRI scan of a healthy aorta and 4D flow mass flow rate profiles [1] were used to develop a three-dimensional model and to validate the CFD simulation. The anastomosis of a HeartMate III LVAD outflow graft (OG) to the aorta was artificially attached using different combinations of geometrical parameters, including (i) the angle between the aorta and the OG, (ii) the rotational position around the aorta, and (iii) the distance from the aortic valve to the OG. The RANS method using the k-e model was used jointly with two inlets, the native cardiac cycle and the centrifugal pump, and, for the pressure outlets, the three-element Windkessel model [2] was used to evaluate the velocity field, wall shear stress distribution, turbulent kinetic energy and perfusion of flow. The findings show that, in this case, the optimal parameters to reduce the reverse flow is to locate the OG at least 50mm from the aortic valve using angles between 45o±10o for both the right and front rotational positions. However, the right position is preferable, because the front position significantly increases the WSS in the aortic root. This research demonstrates the potential of using patient-specific data with CFD to support surgical procedures. This could help to determine the optimum position for the OG in each patient and thus improve the accuracy of the intervention.