Efficacy of N-acetylcysteine in preventing renal injury after heart surgery: a systematic review of randomized trials

The aim of this study was to assess whether perioperative N-acetylcysteine (NAC), an antioxidant, prevents acute renal injury (ARI) after cardiac surgery. We performed a systematic review of randomized controlled trials (RCTs) of NAC in adult cardiac surgery patients. The RCTs were identified by searching MEDLINE (1960-2008), clinicaltrials.gov website, and hand-searching references of relevant publications. Primary outcome was ARI (absolute increase > 0.5 mg/dL or relative increase > 25%, in serum creatinine from baseline within 5 days after surgery). Random effects model was used to perform a meta-analysis. Forest plots and I-2 test were used to assess heterogeneity among studies. Ten RCTs (n = 1163 patients) were included. Mean age was 70 +/- 7.4 years, 71% were male, and 66% underwent coronary artery bypass surgery. N-Acetylcysteine did not reduce ARI incidence [35% NAC vs. 37% placebo; relative risk (RR) 0.91, 95% CI 0.79-1.06, P = 0.24]. Overall, 3.3% of patients required haemodialysis (NAC vs. placebo; RR = 1.13, 95% CI 0.59-2.17) and 3% died (RR = 1.10, 95% CI 0.56-2.16). There was a trend towards reduced ARI incidence among patients with baseline chronic kidney disease assigned to intravenous NAC (RR = 0.80, 95% CI 0.64-1.01, P = 0.06). This meta-analysis of RCTs showed that prophylactic perioperative NAC in cardiac surgery does not reduce ARI, haemodialysis, or death.