Antioxidant supplementations for prevention of atrial fibrillation after cardiac surgery: an updated comprehensive systematic review and meta-analysis of 23 randomized controlled trials

This systematic review with meta-analysis sought to determine the impact of antioxidants (N-acetylcysteine [NAC], polyunsaturated fatty acids [PUFAs] and vitamins) on incidence of postoperative atrial fibrillation (POAF) and duration of length of hospital stay. Medline, Embase, Elsevier, Sciences online database and Google Scholar literature search was made for studies in randomized controlled trials. The effect sizes measured were odds ratio (OR) for categorical variable and standard mean difference (SMD) with 95% confidence interval (CI) for calculating differences between mean values of duration of hospitalization in intervention and control groups. A value of P < 0.1 for Q-test or I-2 > 50% indicated significant heterogeneity between the studies. Literature search of all major databases retrieved 355 studies. After screening, a total of 23 trials were identified that reported outcomes of 4278 patients undergoing cardiac surgery. Pooled effects estimates on POAF showed a significant reduction after NAC (OR: 0.56, 95% CI: 0.40-0.77, P < 0.001), PUFA (OR: 0.84, 95% CI: 0.71-0.99, P = 0.03) and vitamin C treatment (OR: 0.50, 95% CI: 0.27-0.91, P = 0.02). Hospital length of stay was not reduced after NAC therapy (SMD: 0.082, 95% CI -0.09 to 0.25, P = 0.3), but could be decreased with PUFA (SMD: -0.185, 95% CI: -0.35 to -0.018, P = 0.03) and vitamin C (SMD: -0.325, 95% CI -0.50 to -0.14, P < 0.01). In conclusion, perioperative antioxidant supplementations with NAC, PUFA and vitamin C prevent atrial fibrillation after cardiac surgery. Moreover, PUFA and vitamin C are capable to reduce hospital stay, whereas NAC lacks this capacity.