Background:The predictive role of the vasoactive-inotropic score (VIS) for clinical outcomes after venoarterial extracorporeal membrane oxygenation (VA-ECMO) in patients with cardiogenic shock is not well known. This study investigated the predictive value of VIS on in-hospital outcomes and the determination of optimal timing for the initiation of VA-ECMO.Methods and Results:Overall, 160 patients with cardiogenic shock requiring VA-ECMO who were treated between December 2012 and August 2018 were analyzed. The in-hospital outcomes according to VIS were compared. Pre-ECMO VIS had an area under the receiver-operating characteristic curve (AUC) of 0.60 (P=0.03) for the prediction of in-hospital death. When the patients were divided into the high (≥32) and low (<32) VIS groups, the high VIS group had a higher rate of in-hospital death (P=0.002) and a lower rate of ECMO weaning (P=0.004). The difference in in-hospital death according to VIS was significant only in patients with a cardiogenic shock of non-ischemic etiology (P=0.01). Extracorporeal cardiopulmonary resuscitation (hazard ratio HR, 1.99), age (HR, 1.02), pre-ECMO lactate (HR, 1.06), and VIS ≥32 (HR, 2.46) were independently predictive of in-hospital death.Conclusions:Among patients with cardiogenic shock requiring VA-ECMO, the initiation of VA-ECMO before reaching high VIS (≥32) showed better in-hospital outcomes, suggesting that VIS may be a potential marker for determining the initiation of hemodynamic support with VA-ECMO.