Protein oxidation and antioxidant parameters in low risk and high risk patients undergoing off pump coronary artery bypass graft – A comparative study

Background: Coronary artery disease (CAD) patients scheduled for coronary artery bypass grafting (OPCABG) would represent the ideal situation to evaluate the potential injury induced by oxidative stress during ischemia and subsequent reperfusion. This study aims to compare markers of protein oxidation and antioxidants in serum of low risk and high risk patients, before and after undergoing OPCABG. Methods: CAD patients scheduled for OPCABG - Group I: low risk patients (n=50) with ejection fraction > 40%, and group II : high risk patients (n=50) ejection fraction < 40% were included in the study. The mean values of the pre-operative and 24 hours post-operative levels of serum protein oxidation markers (advanced oxidative protein products, protein carbonyl) and antidoxidant parameters (total thiols, total antioxidant activity, total protein and albumin) were compared using ANOVA. Results: In both groups, the post-operative levels of protein oxidation markers were significantly increased (pre-operative vs post-operative p<0.01), while the post-operative levels of the antioxidants parameters were significantly decreased (p <0.01) respectively. In each study group the post-operative levels of the protein oxidation markers were significantly higher than the pre-operative levels (low risk vs high risk group, pre-operative p<0.01, post operative p<0.01), with the antioxidants levels being significantly lower in the high risk group than in low risk group (low risk vs high risk group, pre-operative p<0.01, post operative p<0.01). Conclusion: In patients undergoing OPCABG, the post-operative alterations in oxidative stress and antioxidants is suggestive of a need for similar vigilant clinical observation in both low and high risk groups to prevent post-operative complications.