Objective: This study was designed with two aims: 1) to determine if the coronary artery bypass graft (CABG) procedure alters plasma vitamin E and C concentrations of adult patients through repeated determinations of vitamin levels at time points before, during and following CABG, and 2) to assess whether plasma vitamin E concentrations reflect myocardial tissue content.
Methods: A consecutive sample of 38 patients undergoing CABG surgery at a Midwest tertiary care hospital was enrolled. Patients receiving blood transfusions before or during surgery were excluded.
Results: Plasma vitamin E/total lipid ratios rose with reperfusion, remained elevated immediately following bypass, and fell to preoperative concentrations by 24 hours. Plasma vitamin E/total cholesterol levels varied little throughout this time course. Both plasma uric acid and ascorbate concentrations (corrected for hemodilution) also rose by the preischemic interval, and remained elevated until a return to preoperative levels by 24 hours. Corrected malondialdehyde (MDA) concentrations rose by pre-ischemia but returned more quickly to preoperative levels. Atrial appendage tissue vitamin E concentrations bore a significant relationship to those of plasma prior to surgery (r=+0.49, p=0.004). Reported supplement use, plasma concentrations and body mass index contributed to the variability in atrial tissue concentrations of vitamin E.
Conclusions: In short, when not confounded by transfusions or hemodilution, several peripheral indices of antioxidants increase with the reperfusion segment of CABG procedure and return to baseline levels within 24 hours of surgery. Parallel changes in MDA were observed. The observed changes are consistent with the hypothesis that oxidative stress accompanies the ischemia-reperfusion components of the CABG procedure.