Abstract: AIM: To study the effect of edaravone (MCI-186) on hemodynamics and hepatic and renal function of patients following valve replacement. METHODS: Forty patients with rheumatic heart disease undergoing cardiac valve replacement were randomly divided into two groups. Experimental group (n=20) received edaravone injection (0.5 mg/kg) in venous blood reservoir of cardiopulmonary bypass unit at 10 min before declamping aorta. Control group (n=20) received no edaravone. Hemodynamic parameters were recorded before operation and at 2, 8 and 24 h after declamping aorta and blood samples were taken before operation and at 8, 16 and 72 h after declamping aorta for determination of TBIL, AST, ALT, BUN and Cr. RESULTS: 1)No statistical differences were found in the levels of MAP, HR and PAWP between groups. In both groups, the levels of CI increased at 2, 8 and 24 h, but the levels in experimental group were higher than those in control group at 2 h (P<0.01, 8 h (P<0.05) and 24 h (P<0.01). The levels of SVI and LVSWI at 24 h in experimental group were higher than those in control group (P<0.05). 2)No statistical differences were found in the levels of TBIL, AST, ALT, BUN and Cr between groups, and the levels of BUN and Cr were within the normal range before operation and at 8 h, 16 h and 72 h after in both groups. The levels of TBIL, AST and ALT recovered to normal at 72 h in the two groups. The amount of positive inotropic drugs in experimental group was less than in control group (P<0.05). CONCLUSION: MCI-186, with no significant side effects on hepatic and renal functions, improves the hemodynamic condition and left ventricular functions.