Title: AN EVALUATION OF THE FLOW BALANCE BETWEEN LVAD AND RVAD
Abstract: Background: The clinical benefits of left ventricular assist device (LVAD) have been well proven for the patients of severe heart failure. However, severe right heart failure occurs in approximately 20% to 30% of LVAD patients. Although BVAD implantation is a very effective option for those patients, the flow balance between LVAD and RVAD is still controversial. Methods: Sixteen healthy half-Dexter calves which survived more than two weeks after BVAD implantation were divided into two groups based on the initial two weeks ratio of the left / right pump flow rate (L/R ratio). Survival, mean arterial pressure, mean left atrial pressure, mean pulmonary arterial pressure, CVP and heart rate were compared. Results: Survival in group A (L/R ratio<0.9, n=7) and group B (L/R ratio 0.9, n=9) were 70±23 (37–90) days and 42±16 (22–60) days, respectively. Three out of seven experimental calves in group A were electively sacrificed on post-operative day 90 following the protocol. The results of the other measurements are listed on the table.TableConclusions: From this study, it is recommended to keep the L/R ratio less than 0.9 for initial two weeks after BVAD implantation for longer term survival of BVAD animals. Contrary to what was generally believed traditionally used higher flow for the left pump over right pump did not produce longer survival of calves with BVAD implantation.