Use of N-acetylcysteine to reduce post-cardiothoracic surgery complications: a meta-analysis

Post-cardiothoracic surgery (CTS) complications (e.g. myocardial injury, renal dysfunction, atrial fibrillation) may occur as a result of enhanced systemic inflammation, perhaps provoked by an oxidative stress response. N-acetylcysteine (NAC) is a free radical scavenger antioxidant agent that may attenuate this physiologic response and reduce post-CTS complications. Thus, a meta-analysis was performed to help characterize the potential beneficial effects of perioperative NAC administration in patients undergoing CTS. A systematic literature search in MEDLINE, EMBASE and the Cochrane Library was conducted through April 2008. A search strategy using medical subject headings and text keywords was performed. Results are reported as odds ratios or weighted mean differences with accompanying 95% confidence intervals (CIs). Studies were pooled using a fixed-effect model. The primary outcomes included atrial fibrillation (AF), myocardial infarction (MI), stroke, acute kidney injury (AKI), need for renal replacement therapy (RRT), mortality and total hospital length-of-stay (LOS). Upon meta-analysis of 13 trials (n=1338 subjects), the use of NAC appeared to statistically significantly lower the odds of developing post-CTS AF by 36% (95%CI 2-58%) (n=6 studies). This corresponded to an 8% (1-15%) pooled risk difference and a number-needed-to-treat of 13. NAC did not appear to significantly alter any of the other meta-analysis endpoints. The exclusion of the study utilizing only oral NAC therapy and the study with lower internal validity did not affect the overall conclusions of our meta-analysis. Currently, the most compelling data for using NAC in CTS patients is in post-CTS AF prevention. However, additional, larger randomized controlled trials evaluating this and other postoperative complication endpoints are needed.