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, right (PRA) and left atrial pressure (PLA) measured prior to LVAD support, we predetermined the stressed volume (V) and logarithmic slope of right heart CO curve (SR). Next, we initiated LVAD at maximum level and then decreased LVAD flow stepwise while monitoring hemodynamic changes. We predicted LVAD-induced CO and PRA for given PLA from the predetermined SR and V, and compared with those measured experimentally. The predicted CO [r2=0.907, standard error of estimate (SEE)=5.59 mL/min/kg, p<0.001] and PRA [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 PRA under various right ventricular (RV) functions. It indicated that PRA 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.
- left ventricular assist device
- circulatory equilibrium
- cardiac output curve
- venous return surface
- Copyright © 2016, American Journal of Physiology-Heart and Circulatory Physiology