Prediction of hemodynamics under left ventricular assist device

Left ventricular assist device (LVAD) saves lives in patients with severe left ventricular (LV) failure. However, predicting how much LVAD boosts total cardiac output (CO) remains difficult. This study aimed to develop a framework to quantitatively predict the impact of LVAD on hemodynamics. We adopted the circulatory equilibrium framework and incorporated LVAD into the integrated CO curve to derive the circulatory equilibrium. In anesthetized dogs, we ligated left coronary arteries to create LV failure and inserted a centrifugal pump as LVAD. Using CO and right (P_RA) and left atrial pressure (P_LA) measured before LVAD support, we predetermined the stressed volume (V) and logarithmic slope of right heart CO curve (S_R). Next, we initiated LVAD at maximum level and then decreased LVAD flow stepwise while monitoring hemodynamic changes. We predicted LVAD-induced CO and P_RA for given P_LA from the predetermined S_R and V and compared with those measured experimentally. The predicted CO [r² = 0.907, SE of estimate (SEE) = 5.59 ml·min^-1·kg^-1, P < 0.001] and P_RA (r² = 0.967, SEE = 0.307 mmHg, P < 0.001) matched well with measured values indicating the validity of the proposed framework. We further conducted simulation using the validated framework to analyze the impact of LVAD on P_RA under various right ventricular (RV) functions. It indicated that P_RA is relatively insensitive to changes in RV end-systolic elastance or pulmonary arterial resistance, but sensitive to changes in V. In conclusion, the circulatory equilibrium framework predicts quantitatively the hemodynamic impact of LVAD. This knowledge would contribute to safe management of patients with LV failure undergoing LVAD implantation.

Hemodynamic response to left ventricular assist device (LVAD) has not been quantitatively investigated. This is the first report of quantitative prediction of the hemodynamics on LVAD using circulatory equilibrium framework. The validated framework allows us to simulate the impact of LVAD on right atrial pressure under various right ventricular functions.