Acute In Vivo Evaluation of an Implantable Continuous Flow Biventricular Assist System

Abstract

An implantable biventricular assist device offers a considerable opportunity to save the lives of patients with combined irreversible right and left ventricular failure. The purpose of this study was to evaluate the hemodynamic and physiologic performance of the combined implantation of the CorAide left ventricular assist device (LVAD) and the DexAide right ventricular assist device (RVAD). Acute hemodynamic responses were evaluated after simulating seven different physiological conditions in two calves. Evaluation was performed by fixing the speed of one individual pump and increasing the speed of the other. Under all conditions, increased LVAD or RVAD speed resulted in increased pump flow. The predominant pathophysiologic effect of independently varying DexAide and CorAide pump speeds was that the left atrial pressure was very sensitive to increasing RVAD speed above 2,400 rpm, whereas the right atrial pressure demonstrated much less sensitivity to increasing LVAD speed. An increase in aortic pressure and RVAD flow was observed while increasing LVAD speed, especially under low contractility, ventricular fibrillation, high pulmonary artery pressure, and low circulatory blood volume conditions. In conclusion, a proper RVAD-LVAD balance should be maintained by avoiding RVAD overdrive. Additional studies will further investigate the performance of these pumps in chronic animal models.