In-Silico Evaluation of Effects of Swirl Direction and Intensity on Aortic Flow Patterns Induced by an Aortic Pump Using Computational Fluid Dynamics
Congestive heart failure has reached epidemic proportions in developed countries afflicting an estimated 23 million patients worldwide and more than 5.7 million patients suffering from it annually in USA. Left ventricular assist devices (LVADs) have gained acceptance for non-transplant NYHA Class III & IV HF patients to provide full or partial circulatory support as a bridge to transplant or destination therapy. Recently, investigators have suggested advantages of deploying a continuous flow pump within the aorta, through transcatheter deployment (eg: Abiomed Impella pump) and an anchoring device to lodge the pump across the diameter of the ascending aorta (AAo). In this study we evaluate feasibility of such a device anchored virtually at the AAo of a patient-specific aortic arch, using computational fluid dynamics (CFD). Constant inflow rate conditions of 0.7 m/s in the axial direction with varying swirl / tangential intensity at the AAo inlet (viz. pump outlet) was modeled simulative of a range of conditions affecting aortic helical grade (viz. secondary flow), using FLUENT 14.5 (ANSYS Inc.). A change of swirl intensity from +30% (right-handed, physiological) to −30% (left-handed) swirl led to increases in peak WSS (by 10.31%) and mean WSS (by 13.04%). This simulation based pilot study indicates that WSS in transverse aortic arch is a versatile indicator of non-physiological helical flow grade and may be a promising design parameter for hemodynamics-informed aortic pump design.