BACKGROUND: AVP (arginine vasopressin) shows unique hemodynamic characteristics, as a vasopressor. AVP has been tried in many cathecholamine refractory vasodilatory situations, and sometimes resulted in effective hemodynamic improvement. In this study, we hypothesized that low dose AVP infusion could recover the decreased SVR (systemic vascular resistance) induced by milrinone infusion with minimal effect on PVR (pulmonary vascular resistance). METHODS: Sixteen patients undergoing OPCAB participated in this study. After a loading dose milrinone was infused, low dose vasopressin infusion was started and titrated until the systemic blood pressure increased by 20%. During the study, hemodynamic factors including pulmonary capillary wedge pressure and cardiac output were measured using a continuous thermodilution technique with a Swan-Ganz catheter. RESULTS: Milrinone infusion reduced both SVR and PVR. And vasopression infusion increased SVR, but show relatively less effect on PVR. CONCLUSIONS: Low-dose vasopressin infusion could be used to recover the SVR decrease caused by milirinone infusion with little effect on PVR.