Influence of LVAD Cannula Outflow Tract Location on Hemodynamics in the Ascending Aorta

Abstract

To develop a better understanding of the hemodynamic alterations in the ascending aorta, induced by variation of the cannula outflow position of the left ventricular assist device (LVAD) device based on patient-specific geometries, transient computational fluid dynamics (CFD) simulations using the realizable k-ε turbulent model were conducted for two of the most common LVAD outflow geometries. Thoracic aortic flow patterns, pressures, wall shear stresses (WSSs), turbulent dissipation, and energy were quantified in the ascending aorta at the location of the cannula outflow. Streamlines for the lateral geometry showed a large region of disturbed flow surrounding the LVAD outflow with an impingement zone at the contralateral wall exhibiting increased WSSs and pressures. Flow disturbance was reduced for the anterior geometries with clearly reduced pressures and WSSs. Turbulent dissipation was higher for the lateral geometry and turbulent energy was lower. Variation in the position of the cannula outflow clearly affects hemodynamics in the ascending aorta favoring an anterior geometry for a more ordered flow pattern. The new patient-specific approach used in this study for LVAD patients emphasizes the potential use of CFD as a truly translational technique.