NEW SEQUENTIAL SYNCHRONIZED DRIVING SYSTEM OF INTRAAORTIC BALLOON PUMPING AND LEFT-VENTRICULAR ASSIST DEVICE - INFLUENCE ON ENDOCARDIAL VIABILITY RATIO AND RENAL BLOOD-FLOW IN THEIR COMBINATION

Intraaortic balloon pumping (IABP) and left ventricular assist devices (LVAD) have shown remarkable progress individually, but how to combine them is still unknown. A new sequential synchronized driving system was developed to control concomitant use of IABP and LVAD, and then its hemodynamic effectiveness was evaluated in swine, especially on endocardial viability ratio (EVR) and renal blood flow. This system (pulsatile bypass pump-delay divide system, PBP-DDS) made it possible to change the driving phase of IABP and LVAD easily. In 12 swine, IABP and LVAD were set up, and these devices were driven in the following 5 modes with the PBP-DDS: mode I, IABP alone: mode II, LVAD alone; mode III, IABP + LVAD (same timing); mode IV, IABP (early diastole) + LVAD (late diastole): and mode V, LVAD (early diastole) + IABP (late diastole). EVR was increased more markedly by combined use of both IABP and LVAD (modes III, IV, and V) than by individual drive, but there was no significant difference among these modes. On the other hand, renal blood flow was decreased so dramatically by the same timing optimal counterpulsation method of mode III that it was thought to be harmful for renal function. But, the delay divide combination method of modes IV and V resulted in no change in the renal circulation. So, it was concluded that this delay divide combination mode appeared to be a more promising support to both failed heart and renal circulation.