Abstract

Objectives: Oxidative stress has been implicated in the occurrence of myocardial injury during ischemia-reperfusion. The aim of this study was to investigate the effect of basal total antioxidant capacity (TAOC) on ischemiareperfusion injury.

Patients and Methods: Blood samples were taken from the coronary sinus of 21 patients prior to coronary bypass (basal), at the end of ischemia, five minutes after the removal of the cross clamp (early reperfusion), and 15 minutes after the removal of the lateral clamp (late reperfusion). The levels of TAOC, lipid peroxide (LPO), and lactate dehydrogenase (LDH) were determined. The patients were divided into two groups as follows: group I included 10 patients (8 males, 2 females, mean age 57 years) with TAOC <%60 and group II included 11 patients (10 males, 1 female, mean age 53 years) with TAOC ≥%60.

Results: The levels of LDH and LPO increased, while those of TAOC were suppressed in both groups throughout surgery. The levels of LDH and LPO were higher in group I than those of group II. The TOAC levels in group I were invariably and significantly lower than those of group II (for basal, ischemia, early reperfusion periods, p<0.001; late reperfusion, p<0.05). Inverse relationships were found between the basal TOAC and LPO at all the periods, and with LDH in the late reperfusion period.

Conclusion: Our data suggest that basal TAOC values may be associated with ischemia-reperfusion injury and the degree of ensuing myocardial damage.

Keywords : Antioxidants/metabolism; biological markers; coronary artery bypass; lipid peroxidation; myocardial ischemia/ metabolism; myocardial reperfusion injury/metabolism; oxidative stress