Left Ventricular Assist Device Mode: Co-Pulse Left Ventricular Unloading in Working Mode of Ex Vivo Heart Perfusion

Abstract

<h3>Purpose</h3> As normothermic ex vivo heart perfusion (EVHP), resting mode and working mode have been proposed. Herein we newly developed left ventricular assist device (LVAD) mode in EVHP: a novel EVHP mode that supported heart contraction by co-pulse synchronized LVAD. <h3>Methods</h3> Following resting mode at 0-1 hour, pig hearts (n = 18) were perfused using cellular perfusate in either of resting, working, and LVAD mode at 1-5 hour, and then myocardial function was evaluated in working mode in all cases at 6 hour. Preservation ratio in the evaluation was defined as myocardial function at 6 hour/myocardial function at 1 hour. Metabolic markers were measured every hour. In LVAD mode, LVAD unloaded the perfusate in left ventricle in systolic phase (Figure). <h3>Results</h3> LVAD mode group was significantly associated with higher preservation ratio in cardiac output (LVAD, 76 ± 5; Resting, 33 ± 3; Working, 35 ± 5%, P < 0.001), stroke work, dP/dt max, and dP/dt min, compared with other groups (Table). Glucose consumption were significantly reduced in resting mode group. LVAD mode group was associated with higher myocardial oxygen consumption (MVO₂) (LVAD, 6.1 ± 0.5; Resting, 2.2 ± 0.3; Working, 4.6 ± 0.5 mL O₂/mion/100g, P < 0.001) and higher ATP level (LVAD, 1.6 ± 0.2; Resting, 1.1 ± 0.1; Working, 0.7 ± 0.1 μmol/g, P = 0.003), compared with other groups. <h3>Conclusion</h3> These data suggest that myocardial function was better preserved in LVAD mode than in resting and working mode. Although similar glycolysis activity was suspected in LVAD and working groups, higher final ATP in LVAD group might be explained by reduced external work in LVAD.