A novel intra-ventricular assist device enhances cardiac performance in normal and acutely failing isolated porcine hearts

Background:We recently demonstrated that a novel intra-ventricular membrane pump (IVMP) was able to increase the pump function of isolated beating porcine hearts. In follow-up, we now investigated the impact of the IVMP on myocardial oxygen consumption and total mechanical efficiency (TME) and assessed the effect of IVMP-support in acutely failing hearts.Methods:In 10 ex vivo beating porcine hearts, we studied hemodynamic parameters, as well as arterial and coronary venous oxygen content. We assessed cardiac power (CP), myocardial oxygen consumption (MVO₂), and TME (CP divided by MVO₂) under baseline conditions and during IVMP-support. Additionally, five isolated hearts were subjected to global hypoxia to investigate the effects of IVMP-support on CP under conditions of acute heart failure.Results:Under physiological conditions, baseline CP was 0.36 +/- 0.10 W, which increased to 0.65 +/- 0.16 W during IVMP-support. This was accompanied by an increase in MVO2 from 18.6 +/- 6.2 ml/min at baseline, to 22.3 +/- 5.0 ml/min during IVMP-support. As a result, TME (%) increased from 5.9 +/- 1.2 to 8.8 +/- 1.8. Acute hypoxia-induced cardiac pump failure reduced CP by 35 +/- 6%, which was fully restored to baseline levels during IVMP-support in all hearts.Conclusion:IVMP-support improved mechanical efficiency under physiological conditions, as the marked increase in cardiac performance only resulted in a modest increase in oxygen consumption. Moreover, the IVMP rapidly restored cardiac performance under conditions of acute pump failure. These observations warrant further study, to evaluate the effects of IVMP-support in in vivo animal models of acute cardiac pump failure.