Abstract 15064: Control of Left Ventricular Load and Pulsatility by a Continuous-flow Left Ventricular Assist Device With a Native Heart Load Control System in Chronic Awake Phase

Abstract

Introduction: We have previously developed a Native Heart Load Control System for a continuous-flow left ventricular assist device (EVAHEART) and demonstrated that the rotational speed (RS) in synchronization with the cardiac cycle can alter left ventricular (LV) load and pulsatility under general anesthesia. In this study, we assessed this system in chronic awake phase. Methods: We implanted EVAHEART in five goats (59.4±5.6kg) with a normal heart. Two weeks after the implantation, we examined the effects of the continuous mode (constant RS), counter-pulse mode (increase RS in diastolic phase) and co-pulse mode (increase RS in systolic phase) of this system on LV load and pulsatility in 100%, 75% and 50% bypass. We used two parameters to evaluate LV load, including stroke work (SW) and end-diastolic volume (LVEDV) determined from LV pressure-volume loops. About pulsatility, we used pulse pressure (PP) and mean dP/dt max of aortic pressure. Results: The co-pulse mode created greater LV load and pulsatility than the continuous mode in all bypass rates. In contrast, LV load and pulsatility in the counter-pulse mode were smaller than those in the continuous mode. There were statistically significant differences between values about LV load and pulsatility in counter-pulse and co-pulse mode; continuous/counter-pulse/co-pulse SW (ml·mmHg); 2601.71±2208.50/2127.88±1745.11/2845.54±2230.82 (100%): 2968.05±2265.75/2485.79±1714.07/3133.92±2203.64 (75%): 3134.42±2319.75/2927.76±2111.76/3313.13±2350.49 (50%), LVEDV (ml); 52.79±26.43/46.95±20.31/56.32±25.43 (100%): 57.22±28.19/51.38±21.83/59.06±26.63 (75%), 59.59±28.24/56.02±25.40/61.88±28.61 (50%), PP (mmHg); 30.09±10.01/22.63±8.09/36.79±9.32 (100%): 32.88±9.88/26.66±10.80/40.69±7.83 (75%): 37.30±10.86/32.76±12.43/41.97±9.59 (50%), mean dP/dt max of aortic pressure (mmHg/s); 979.89±369.20/687.98±230.12/1165.67±391.36 (100%): 1321.25±446.14/1047.78±393.29/1474.99±474.53 (75%): 1511.06±519.18/1332.6±471.91/1666.59±511.55 (50%). Conclusions: Our newly developed system could control LV load and pulsatility in the chronic awake phase. This system may provide the most favorable LV loading conditions for the recovery of the native heart.