Quantitative Prediction Of Impact Of Left Ventricular Assist Device (Lvad) On Hemodynamics

Background Although LVAD has been saving many lives in patients with end stage heart failure, the quantitative prediction of LVAD on hemodynamics remains to be established. Theoretical analysis We developed a framework of circulatory equilibrium where the cardiac output (CO) curve and venous return surface (VRS) were expressed as the function of right (P RA ) and left atrial pressure (P LA ). The CO curve is algebraically derived using the concept of ventricular arterial (VA) elastance coupling. Incorporating LVAD into the VA coupling indicates that LVAD support (CO VAD ) increases left ventricular (LV) afterload and decreases native CO (CO LV ). The total CO (CO total ) becomes CO total =CO LV +CO VAD EF e where EF e approximates ejection fraction. In contrast, LVAD does not change the VRS or right ventricular CO curve. Equilibrating the CO total curve and VRS yields CO, P RA and P LA . Methods/Results In 6 anesthetized, vagotomized dogs, we isolated the carotid sinuses to abolish baroreflex. We ligated coronary arteries to create LV failure and inserted LVAD. We changed CO VAD stepwise from 0 to 100 ml/kg/min and predicted CO total , P LA and P RA in each LVAD support. As shown, predicted CO total , P LA and P RA quantitatively matched well with those measured. Conclusion The proposed framework predicts the impact of LVAD on hemodynamics and thus contributes to the optimal management of patents on LVAD.