Antioxidant supplementation attenuates oxidative stress in patients undergoing coronary artery bypass graft surgery

Ischemia-reperfusion has been reported to be associated with augmented oxidative stress in the course of surgery, which might be causally involved in the onset of atrial fibrillation (AF), the most common arrhythmia after cardiac surgery. We hypothesized that supplementation of antioxidants and n-3 polyunsaturated fatty acids (n-3 PUFAs) might lower the incidence of AF following coronary artery bypass graft (CABG) surgery. In the present study, by monitoring oxidative stress in the course of CABG surgery, we analyzed the efficacy of vitamins (ascorbic acid and α-tocopherol) and/or n-3 PUFAs (eicosapentaenoic acid and docosahexaenoic acid). Subjects (n = 75) were divided into 4 subgroups: control, vitamins, n-3 PUFAs, and a combination of vitamins and n-3 PUFAs. Fluorescent techniques were used to measure the antioxidative capacity, i.e. ability to inhibit oxidation. Total peroxides, endogenous peroxidase activity, and antibodies against oxidized LDL (oLAb) were used as serum oxidative stress biomarkers. Post-operative increase in oxidative stress was associated with the consumption of antioxidants and a simultaneous onset of AF. This was confirmed through an increased peroxide level and a decreased oLAb titer in control and n-3 PUFAs groups, indicating the binding of antibodies to oxidative modified epitopes. In both subgroups that were supplemented with vitamins, total peroxides decreased, and the maintenance of a constant IgG antibody titer was facilitated. However, treatment with vitamins or n-3 PUFAs was inefficient with respect to AF onset and its duration. We conclude that the administration of vitamins attenuates post-operative oxidative stress in the course of CABG surgery.