RESUMO
BACKGROUND: Renal dysfunction is a common complication after cardiovascular surgery. Controversial issues have been discussed regarding the role of N-acetyl cysteine in the prevention of postoperative renal dysfunction. The purpose of this meta-analysis is to assess whether N-acetyl cysteine offers any protection against the development of acute renal dysfunction after cardiac surgery. METHODS: Multiple databases were searched for randomized trials comparing the role of N-acetyl cysteine and placebo in human patients undergoing cardiac surgery. End-points studied were: the incidence of acute renal failure, hemodialysis, early mortality, duration of hospital stay, and maximal change in creatinine values. Dichotomous variables were compared using the risk difference (RD) calculated with inverse weighting; continuous data was pooled as (standardized) mean difference. Results are presented with 95% confidence interval (P < .05 is significant); results are presented within 95% confidence interval. RESULTS: Thirteen randomized trials (713 and 707 patients in the N-acetyl cysteine and control groups, respectively) were included in the present analysis; nine dealing with patients at high-risk for acute renal failure. The incidence of postoperative acute renal dysfunction was 23% and 36% in the N-acetyl cysteine and control cohorts, respectively. N-acetyl cysteine therapy did not reduce acute renal dysfunction in the high-risk cohort [RD -0.03 (-0.09 to 0.02); P = .22; I2 = 24%]. Maximal change in creatinine levels after surgery was also comparable [standardized mean difference 0.07 (-0.23, 0.09); P = .39]. Early mortality was 2.9% and 3.7% in the N-acetyl cysteine and control cohorts respectively; [RD 0 (-0.03 to 0.02); P = .63; I2 = 20%]. Hospital stay (mean length of stay 10.4 and 10.1 days in the N-acetyl cysteine and control cohorts, respectively) was also similar in both cohorts [WMD 0.17 (-0.02 to 0.37) days; P = .81]. CONCLUSION: Prophylactic N-acetyl cysteine therapy does not reduce the incidence of renal dysfunction in high-risk patients undergoing cardiac surgery.