N-acetylcysteine decreases myocardial ischaemiareperfusion injury in CABG patients: 094
Introduction: Perfusion of the myocardium after an ischaemic cross-clamp period, frequently results in depressed myocardial function . N-acetyl-L-cysteine (NAC) has antioxidant, cytoprotective, and microcirculatory effects. It restores the cellular antioxidant potential by replenishing depleted reduced glutathione (GSH) stores and scavenging of oxygen free radicals. It has an antioxidant effect and may limit organ dysfunction during ischaemia reperfusion (I/R) . The aim of this randomized study was to investigate the antioxidant effects of NAC to prevent myocardial I/R injury after the crossclamp period in CABG operations with CPB.
Method: After the ethic committee approval and informed consent, 20 patients undergoing elective coronary bypass operations with CPB were enrolled and divided into group NAC and group Control. Routine propofol based CABG anaesthesia was given to all patients. Group NAC received an iv. infusion at induction of anaesthesia until the end of CPB. Group Control received 5% dextrose in water. Blood samples were taken from the coronary sinus at the start of CPB, before aortic CC and 45 minutes after the completion of proximal anastomoses. Two myocardial biopsies were taken; with the start of CPB before aortic CC, and the second 30 minutes after the completion of proximal anastomoses. TNF-α was assayed with ELISA, reactive oxygen species (ROS) with Chemiluminescence (CML) Technique: Two types of enhancers can be used, Luminol for hydrogen peroxide and hypochloride, Lucigenin for superoxide. All the results are given as mean ± SD. Data were analysed with one- and two-way analysis of variance, Student's unpaired t-test, the Fischer's exact test. P value less than 0.05 was considered significant.
Discussion: There are two main hypotheses, namely oxidative stress and Ca2+ overload which have been proposed to explain to pathogenesis of I/R injury. The role of NAC on the oxidative stress has shown as an O2 free radical scavenger during open heart surgery. Its beneficial effects during hepatic I/R was written by Sener . According to our data we suggested that NAC can be used as an agent to prevent the heart from I/R injury.
1 Boyle EM, Jr. Pohlman TH, Cornejo CJ, et al. Endothelial cell injury in cardiovascular surgery: ischemia reperfusion. Ann Thorac Surg
© 2004 European Society of Anaesthesiology
2 Sener G, Tosun O, Sehirli AO, et al. Melatonin and N-acetylcysteine have beneficial effects during hepatic ischemia and reperfusion. Life Sci