Abstract 2519: Prevention of Postoperative Atrial Fibrillation With the Supplementation of Omega 3 PUFA Plus Antioxidant Vitamins in Patients Undergoing Cardiac Surgery With Extracorporeal Circulation
Reactive oxygen species have been involved in the pathogenesis of postoperative atrial fibrillation in cardiac surgery with extracorporeal circulation due to the unavoidable occurrence of an ischemia-reperfusion cycle. Omega 3 polyunsaturated fatty acids (PUFA) enhance antioxidant enzymes in experimental models, an effect likely to protect against oxidative challenges of myocardium. Supplementation with antioxidant vitamins C and E would further reinforce the antioxidant defences. Eighty three patients scheduled to cardiac surgery with extracorporeal circulation were randomized to either placebo (n=41) or supplementation with omega 3 PUFA (1 g/12 h) followed by vitamin C (500 mg/12h) and vitamin E (400 IU/24 h) (n=42) from 7, 2 and 2 days prior to surgery. Blood samples were drawn throughout the protocol. Right atrial appendages were dissected during surgery to determine the reduced/oxidized glutathione ratio (GSH/GSSG) and biomarkers of oxidative damage such as malondi-aldehyde and protein carbonylation. Western blot was used to determine the expression of the catalytic (NOX-2) and the cytosolic (p47phox) subunits of NADPH oxidase. The activity of catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) were measured in atrial tissue and erythrocytes. The supplementation reduced the incidence of atrial fibrillation by 73%. In atrial tissue, supplemented group exhibited 21% lower lipid peroxidation than placebo group (p<0.03) and lower expression of NOX-2/gp91phox and p47phox subunits. The activities of CAT, SOD and GSH-Px were 132%, 35% and 49% higher in the supplemented patients respect to placebo ones, respectively. In contrast, the activity of the antioxidant enzymes in erythrocytes was not different between groups. Atrial MDA levels correlated to plasma MDA levels (r=0.7484, p<0.0001). Plasma MDA was 16.8% higher in patients who developed atrial fibrillation (p<0.05). Data are consistent with an adaptive antioxidant response in atrial tissue following omega 3 PUFA exposure. Supplementation with omega 3 PUFA plus antioxidant vitamins attenuates the myocardial biochemical and functional injury and markedly decreases the occurrence of postoperative atrial fibrillation.
Supported by FONDECYT grant 1070948