Is the Diameter of the Outflow Graft the Crucial Difference in Stroke Rates Between Heartmate II and HVAD? A Computational Fluid Dynamics Study

Abstract

Purpose:We hypothesised that the difference in stroke rates observed in the ENDURANCE trial between HVAD and Heartmate II could be attributed to the difference in outflow graft diameters. Cerebral blood flow (CBF) patterns in the neck vessels was compared between 1. Normal pulsatile blood flow 2. A continuous flow pump (CFP) with a 10 mm outflow graft 3. CFP with a 14 mm outflow graft Methods: CT scan of a patient was converted into a 3D geometric model using Image Segmentation and Registration tool kit and a mesh for fluid structure interaction was prepared with four noded shell elements for the aortic wall and a tetrahedral fluid element. The complete human arterial tree model was built in Simulink .A CFP output of 5.8 Ltr/min and completely closed aortic valve condition was considered in the computational fluid dynamics analysis and the flow in the cerebral vessels was a DERIVED parameter and NOT given as an input. we studied CBF in