Background Myocardial protection during off-pump coronary artery bypass grafting (OPCABG) is a multifactorial problem in which maintaining stable systemic hemodynamics is very important. In this study passive graft perfusion (PGP) was applied to investigate the effect during and after OPCABG as evaluated by cardiac troponin I (CTnl) and hemodynamic indexes.Methods Thirty first-time patients underwent OPCABG under one surgeon. They were randomly divided into two groups: The passive graft perfusion group (PGP, n=15) received distal coronary perfusion during the anastomosis and immediate graft perfusion after the distal anastomosis. The control group, no graft perfusion group, (NGP, n=15)received no graft perfusion after the distal anastomosis. The results of the two protocols were evaluated by concentration of CTnl and hemodynamic indexes before induction and after operation.Results There were no statistically significant differences between these two groups in their perioperation parameters.The level of CTnl increased postoperatively, reached its peak at 6 hours (P＜0.05) and recovered by the 6 days postoperative. Compared with the control group the concentration of CTnl in the PGP group was significantly lower at 6 and 24 hours (P＜0.01). Compared with the NGP group, cardiac index (Cl) in the PGP group was higher at 12 and 24 hours after operation (P＜0.05). The period of mechanical ventilation was significantly shorter in the PGP group than in the NGP group (P＜0.05).Conclusion PGP can increase the flow to the myocardium and shorten the heart ischemia time, thus maintain stable systemic hemodynamics, supply a satisfactory Cl after surgery and improve surgery outcome.