N-acetylcysteine and magnesium improve biochemical abnormalities associated with myocardial ischaemic reperfusion in South Indian patients undergoing coronary artery bypass grafting: a comparative analysis

Kurian GA, Paddikkala J
Correspondence: Dr Gino A Kurian, ginokurian@hotmail.com

ABSTRACT
Introduction The clinical presentation of ischaemic reperfusion in postoperative patients correlates with oxidative stress. The limited clinical success of anti-ischaemic reperfusion agents has prompted a comparison of the efficacy of N-acetylcysteine (NAC) and magnesium (Mg) in South Indian patients undergoing coronary artery bypass grafting (CABG).
Methods In Clinical Trial I, 52 South Indian patients who had undergone CABG surgery (with intraoperative Mg supplementation) and 40 controls (without Mg supplementation) were selected and matched. The control patients underwent the same protocol without Mg. In Clinical Trial II, the study population consisted of 50 patients, where 25 patients received NAC just before the release of the aortic cross clamp. In the NAC untreated group, dextrose solution was administered at the same time as the placebo. Six blood samples were taken at different times during the cardiac surgery and the antioxidant enzymes, ATPase and cardiac markers from the coronary sinus blood samples were analysed.
Results Increased blood lipid peroxidation was observed in patients who were not treated with Mg/NAC. The administration of Mg/NAC just before the release of the aortic cross clamp reduced the lipid peroxidation significantly (p-value is less than 0.05). The above observations were supported by the antioxidant enzyme levels. Significant improvements to the erythrocyte ATPase and cardiac markers in patients treated with Mg/NAC correlated with a reduction in postoperative abnormalities. Based on the biochemical status of the patients, Mg was shown to mediate better recovery from postoperative changes.
Conclusion NAC and Mg decreased pump-induced oxidative stress during cardiopulmonary bypass (CPB), suggesting that it could be a novel therapy for assisting in the prevention of CPB-induced oxidative stress.

Keywords: coronary artery bypass graft, free radicals, N-acetylcysteine, reperfusion injury
Singapore Med J 2010; 51(5): 381-388