N-acetylcysteine as an additive to crystalloid cardioplegia increased oxidative stress capacity in CABG patients.

Objective: This prospective, randomized study was designed to assess the effects of N-acetylcysteine (NAC) in coronary artery bypass graft (CABG) patients.

Design: Thirty-five consenting CABG patients with normal myocardial function were randomly divided into control (C) patients (N = 20) who received crystalloid (Plegisol) cardioplegia, and NAC patients receiving NAC in a 0.04 mol/l solution (N = 15) in Plegisol. Simultaneous coronary sinus and aortic blood samples, and myocardial biopsies were taken 1, 5 and 10 min after declamping. Hemodynamics was measured invasively for 24 h.

Results: There were no adverse effects observed. The myocardial glutathione content was significantly better preserved (p = 0.0001) and myeloperoxidase activity was over two times lower in the NAC group than in the C group (p = 0.03). The trap capacity gradient between the aorta and the coronary sinus increased significantly during the first minute of reperfusion in the treatment group (p = 0.001) when compared with the C group. In the first minute after reperfusion there were more leukocytes sequestered in the coronary circulation (p = 0.04) in the C group. The invasive hemodynamic data did not differ significantly between the groups. The incidence of arrhythmias was equal.

Conclusion: NAC increased tissue capacity against oxidative stress and decreased inflammatory response in CABG patients with normal ejection fraction.