Cardioprotective effect of cold-blood cardioplegia enriched with N-acetylcysteine during coronary artery bypass grafting.

Background: Cold-blood cardioplegia is a well-known method in coronary artery bypass graft surgery, and several authors have used various agents in the enrichment of cold-blood cardioplegia to decrease ischemia-reperfusion injury seen during surgery. N-acetylcysteine, which can increase glutathione levels, is one of the agents added to cardioplegic solutions to decrease myocardial injury. This study was planned to assess the efficiency of N-acetylcysteine-enriched cold-blood cardioplegia on early reperfusion injury in patients with ischemic heart disease undergoing coronary artery bypass grafting, using measurements of cardiac troponin I and malondialdehyde release.

Methods: Thirty patients (11 women and 19 men) with left ventricular ejection fraction greater than 0.40 scheduled for coronary artery bypass grafting were randomly divided into two groups. We used cold-blood cardioplegia enriched with N-acetylcysteine (50 mg per kilogram of body weight) in the first group and cold-blood cardioplegia alone in the second group. Hemodynamic variables and clinical properties of the patients were preoperatively and postoperatively evaluated. Enzyme releases were measured in the early hours after the operation.

Results: In the N-acetylcysteine-enriched group cardiac troponin I levels were lower than in the N-acetylcysteine-free group, and this difference was statistically significant. Cardiac troponin I levels increased in both groups in the 6th and 12th hours postoperatively, but there was a statistically significant difference between the two groups. Malondialdehyde levels were significantly higher in the N-acetylcysteine-free group after the 6th, 12th, 24th, and 48th hours postoperatively when compared with the N-acetylcysteine-enriched group.

Conclusions: N-acetylcysteine-supplemented cold-blood cardioplegia minimizes myocardial injury in the early hours after and during the cardiac surgery.