Abstract 13637: Quantitative Prediction of the Hemodynamic Impact of Left Ventricular Assist Device
BACK GROUND: Left ventricular assist device (LVAD) has been saving many lives in patients with severe left ventricular (LV) failure. Because of its remarkable performance, it has been increasingly used as a destination therapy. It remains unknown, however, how LVAD cooperates with LV and determines total cardiac output (CO). The aim of this study is to develop a framework to quantitatively predict the hemodynamic impact of LVAD. THEORETICAL ANALYSIS: We developed a circulatory equilibrium framework (AJP 2004) where we represented both the CO curve and venous return surface (VRS) as a function of the right (PRA) and left atrial pressure (PLA). The intersection between CO curve and VRS gives the circulatory equilibrium. LVAD flow (COVAD) increases arterial pressure independent of CO of LV (COLV), thereby increases LV afterload, which shifts the COLV curve downward. Adding the shifted COLV curve to COVAD yields the total CO (COtotal) curve. Theoretical analysis using the ventricular arterial coupling concept yields COtotal=COLV+COVADEF (EF: ejection fraction). In contrast, LVAD does not change the VRS or right ventricular CO curve. As a result, LVAD increases COtotal and decreases PLA, while does not change PRA.
METHODS/RESULTS: In 5 anesthetized dogs, we isolated the carotid sinuses and vagotomized bilaterally. After a median sternotomy, we ligated coronary artery to create LV failure. We inserted LVAD, and measured COtotal, PLA and PRA under various levels of COVAD (0-100 ml/kg/min). We determined the parameters of CO curve in each dog and evaluated EF (2D echo). Predicted COtotal, PLA and PRA matched well with those measured (SEE=7.98 ml/kg/min, 1.09 mmHg and 0.31 mmHg, respectively, r2=0.93, 0.94 and 0.99, respectively).
CONCLUSION: The proposed framework would contribute to the safe management of LVAD in patients with severely compromised hemodynamics. It would open up a possibility to automatically regulate LVAD to adapt dynamically changing hemodynamic needs.
- © 2012 by American Heart Association, Inc.