Abstract: Objective To invest igate the effect of p ro staglandin E1 (PGE1 ) during off-pump co ronary artery bypass graft ing (O PCAB ). Methods F rom O ct. 2005 to Dec. 2005, 40 consecut ive pat ients w ho underw ent O PCAB w ere random ly divided into two group s. The cont ro l group received convent ional t reatment w h ile the PGE1 group received cont inuous int ra2vena PGE1 infusion ( 5220 ngouml;k g?m in) fo r 24248 hours. The perioperat ivehemodynam ic indexes, including cardiac index (C I) , system ic vascular resistance ( SVR ) , pulmonary vascular resistance (PVR ) , and hematocrit (HCT ) , coagulation index (C I) , partial pressure of oxygen in artery (PaO 2 ) ,serum creat inine (Cr) and blood urea nitrogen (BUN ) were measured and compared. Results Postoperative SVR and PVR decreased and C I increased significantly in the PGE1 group (P lt; 0. 05). Postoperative HCT decreased in the both group patients. Coagulation index decreased significantly on the operation day, but then increased in both groups on the next day after operation, with the increase in the PGE1 group significantly less than control group (P lt;0. 05). Postoperative serum Cr and BUN increased significantly in the both groups, especially in the control group (P lt; 0105). Conclus ion PGE1 has potential beneficial effect on patients undergoing OPCAB.