Performance Analysis of Axial Flow Left Ventricular Assist Devices Under different working modes Based on the Numerical Model

The effect of working modes of axial flow left ventricular assist devices (LVADs) on blood perfusion has not been clearly elucidated. In this study, hemodynamics of axial flow LVAD was investigated by using the numerical model of the cardiovascular system coupled with LVAD. The numerical model subdivides the human circulatory system into several lumped parameter blocks, which are represented by various circuit elements. In this paper, we chosen three working modes of axial flow LVADs, named, the co-pulse, counter pulse and constant speed modes. Results show that the blood fluid flowed smoothly along the whole passage under three working modes. The co-pulse mode was suitable for patients with certain cardiac function because this mode kept high blood perfusion during systole and reduced the pressure load on the aorta the diastole. By contrast, the counter pulse mode was more suitable for patients with severely impaired cardiac function because this mode kept a high blood perfusion during a whole cardiac cycle.