Oxidative stress in patients undergoing cardiac surgery: comparative study of revascularization and valve replacement procedures

OBJECTIVE: The aim of this study was to evaluate the time course of oxidative stress markers in plasma and erythrocyte from patients undergoing open heart surgery with cardiopulmonary bypass (CPB) and to examine whether the type of surgical technique used (valve replacement or coronary revascularization) produces any differences in these makers. PATIENTS AND METHODS: Twenty-two patients undergoing cardiac surgery with CPB were divided in 2 groups (valve replacement or coronary revascularization). We took 5 blood samples at different times during cardiac surgery and analyzed thiobarbituric acid reactive substances (TBARS), alpha-tocopherol, coenzyme Q, and retinol in plasma and TBARS (baseline levels and induced by Fe(2+)-ascorbate oxidation), alpha-tocopherol, coenzyme Q and catalase, superoxide dismutase, and glutathione peroxidase activity in erythrocyte. RESULTS: Plasma alpha-tocopherol content decreased after starting CPB in both groups. In contrast, in erythrocytes there was an increase in the activity or concentration of all of the antioxidants. Erythrocyte TBARS contents, both baseline levels and induced levels, were higher in coronary revascularization group. CONCLUSION: Although both groups suffered an increase in oxidative stress after CPB, this increase was higher in coronary revascularization group and therefore the possibility of post-CPB complications could be more severe in this group. As the groups followed a different pattern of antioxidant response, a different therapeutic approach may be required for each.