Mathematical analysis of the effects of valvular regurgitation on the pumping efficacy of continuous and pulsatile left ventricular assist devices

• We numerically investigated the physiological relationship between the severity of regurgitation and the effect of a left ventricular assist device (LVAD) on cardiovascular system responses.
• Under conditions of mitral regurgitation, the effects of both pulsatile and continuous LVAD treatment on ventricular unloading were significant.
• Under conditions of aortic regurgitation (AR), the effects of the LVADs on ventricular unloading were not significant. The effects of LVAD treatment decreased according to the severity of AR.

BackgroundA left ventricular assist device (LVAD) is normally contraindicated in significant aortic regurgitation (AR) and requires intraoperative valve repair or exclusion. Nevertheless, AR can coexist with an LVAD, so a valid question when asked might still be of clinical significance. The purpose of this study is to analyze the effects of valve regurgitation on the pumping efficacy of continuous and pulsatile LVADs with a computational method.MethodsA cardiovascular model was developed based on the Windkessel model, which reflects the hemodynamic flow resistance and the blood wall elasticity. Using the Windkessel model, important cardiovascular components, such as the right atrium, right ventricle, pulmonary artery, pulmonary vein, left atrium (LA), left ventricle (LV), aorta, and branching blood vessels, were expressed.ResultsIn the case of AR, continuous and pulsatile LVADs improved cardiac output and reduced mechanical load slightly. In the case of mitral regurgitation, the LVADs improved cardiac output (cardiac outputs were about 5 L/min regardless of the severity of regurgitation) and reduced afterload significantly.ConclusionAR reduced both continuous and pulsatile LVAD function significantly while mitral regurgitation did not affect their pumping efficacy.