Pharmacodynamics of malondialdehyde as indirect oxidative stress marker after arrested-heart cardiopulmonary bypass surgery.

An unavoidable consequence of cardiac surgery is oxidative stress and resulting peroxidation of biological molecules, in particular unsaturated lipids. The detection of peroxidation metabolites in biological environments is difficult due to their large variety, small concentration, and high reactivity. One of the most studied lipid peroxidation products is malondialdehyde and as such an important marker of oxidative stress. The aim of this study was to monitor the perioperative serum concentration of malondialdehyde as an oxidative stress marker in patients undergoing arrested-heart cardiopulmonary bypass surgery. This observational study was performed on 40 patients scheduled for on-pump arrested-heart open-heart surgery. Blood samples for the analysis of serum malondialdehyde were obtained preoperatively and intraoperatively immediately after the aortic clamp was removed. Afterwards, samples were obtained 12, 24, 48 and 72 h postoperatively. A gas chromatography-mass spectrometry analytical method was used to detect serum concentrations of malondialdehyde. A significant increase in serum malondialdehyde concentration was detected at the time of aortic declamping. The malondialdehyde serum concentration continued to increase and peaked 12 h postoperatively. Afterwards it started to decline, but remained significantly higher compared to preoperative values both at 24 and 48 h postoperatively. In contrast to some previous studies, our results demonstrate that in this patient population, the malondialdehyde levels do not peak at the end of the surgery, but continue to rise a few hours after surgery. Our findings indicate that in this patient population, oxidative stress with consequent lipid peroxidation is maintained and is even attenuated in the early postoperative period. This study was registered with the ISRCTN Registry under the trial registration number ISRCTN98572043.