The Hemodynamic Comparative Study Between Pulsatile and Non-Pulsatile VA ECMO: A Primary Numerical Study

Although pulsatile ECMO, as novel kinds of ECMO, has been attracted more and more attention, the differences of the hemodynamic effects of the pulsatile ECMO on the aorta, the cerebral perfusion, and left ventricular work were still under-investigated. The aim of this study was to clarify the hemodynamic differences of the cardiovascular system between the pulsatile and non-pulsatile VA ECMO. In this study, three ECMO support modes, named as "constant flow mode", "co-pulse mode" and "counter pulse mode", were designed. The computational fluid dynamics (CFD) study was carried out. The distribution of the oxygenated blood, the blood velocity vector, the oscillatory shear index (OSI), the relative residence time (RRT), the left ventricular external work (EW), the equivalent left ventricular afterload (EAL) and the energy loss of cardiovascular system (EL) were calculated to compare the hemodynamic differences. The simulation results demonstrate that the oxygenated blood under co-pulse mode was easier to perfuse into the three braches vessels than that under both other modes. In addition, the ECMO under counter pulse mode could also achieve lowest RRT (constant flow mode 220 vs. co-pulse mode 132 vs. counter pulse mode 93). Similarly, the ECMO under counter pulse mode could significantly reduce the left ventricular external work (co-pulse mode 1.51 w vs. constant flow mode 1.44 w and counter pulse mode 1.30 w), left ventricular afterload (constant flow mode 1.03 mmHg.s/ml vs. co-pulse mode 1.67 mmHg.s/ml vs. counter pulse mode 0.82 mmHg.s/ml) and energy loss of arterial system (constant flow mode 0.18 w vs. co-pulse mode 0.50 w vs. counter pulse mode 0.16 w). In short, the ECMO under counter pulse mode could have advantages to the left ventricular unloading. In contrast, the ECMO under co-pulse mode has more benefit to cerebral oxygen perfusion.