Transient performance analysis of centrifugal Left Ventricular Assist Devices coupled with Windkessel model: LES study on Continuous and Pulsatile Flow operation

Abstract

Abstract Computational Fluid Dynamics (CFD) simulations are widely used to develop and analyze blood-contacting medical devices such as Left Ventricular Assist Devices (LVADs). This work presents an analysis of the transient behavior of two centrifugal LVADs with different designs: HeartWare VAD and HeartMate3. A scale-resolving methodology is followed by means of Large Eddy Simulations. The 3D LVAD models are coupled to a 0D 2-element Windkessel model, which accounts for the vascular resistance and compliance of the arterial system downstream of the device. Furthermore, both continuous- and pulsatile-flow operation modes are analyzed. For the pulsatile conditions, the artificial pulse of HeartMate3 is imposed, and CFD results are compared to those obtained by accessing the quasi-stationary maps of the pumps. Although the quasi-stationary results in terms of efficiency and hemolysis are not realistic, this approach can be used as a rapid tool to provide a preliminary approximation of the pulsatile evolution of flow rate, pressure head, and power, entailing a significant reduction of 99% in computational cost.