[Efficacy of continuous intraoperative administration of low-dose milrinone during the circumflex artery anastomosis of off-pump coronary artery bypass].

BACKGROUND: We have experienced instability of hemodynamic state during off-pump coronary artery bypass (OPCAB), especially, circumflex (Cx) artery anastomosis. Although some reports have implied the efficacy of mirlinone in OPCAB anastomosis due to its characteristic inotropic effect without increasing myocardial oxygen consumption, we examined the effect of smaller doses of mirlinone during Cx anastomosis. METHODS: Fourteen patients received milrinone (M group) continuously at a rate of 0.15-0.30 microg x kg(-1) min(-1) after sternotomy until the end of operation. Sixteen patients in the control group (C group) received saline. Norepinephrine was concomitantly administered for maintaining systolic blood pressure above 100 mmHg. We measured hemodynamic parameters during Cx anastomosis and postoperative myocardial isozymes, and examined arrhythmias. RESULTS: In the M group mean pulmonary arterial pressure (MPAP) decreased significantly and cardiac index (CI) and SvO2 increased significantly, compared with C group. M group showed lower incidence of atrial fibrillation for 2 days. CONCLUSIONS: We conclude that low-dose milrinone has a good influence on intraoperative and postoperative managements of OPCAB surgery.