Surgical Ablation for Atrial Fibrillation in Cardiac Surgery: A Meta-Analysis and Systematic Review

OBJECTIVES:: This meta-analysis sought to determine whether surgical ablation improves clinical outcomes and resource utilization compared with no ablation in adult patients with persistent and permanent atrial fibrillation (AF) undergoing cardiac surgery. METHODS:: A comprehensive search was undertaken to identify all randomized (RCT) and nonrandomized (non-RCT) controlled trials of surgical ablation versus no ablation in patients with AF undergoing cardiac surgery up to April 2009. The primary outcome was sinus rhythm. Secondary outcomes included survival and any other reported clinically relevant outcome or indicator of resource utilization. Odds ratios (OR) and weighted mean differences (WMD) and their 95% confidence intervals (95% CI) were analyzed as appropriate using the random effects model. Heterogeneity was measured using the I statistic. Meta-regression was performed to explore the relationship between the benefit from surgical AF and duration of follow-up. RESULTS:: Thirty-three studies met the inclusion criteria (10 RCTs and 23 non-RCTs) for a total of 4647 patients. The number of patients in sinus rhythm was significantly improved at discharge in the surgical AF ablation group versus (68.6%) the surgery alone group (23.0%) in RCTs (OR 10.1, 95% CI 4.5-22.5) and non-RCTs (OR 7.15, 95% CI 3.42-14.95). This effect on sinus rhythm (74.6% vs. 18.4%) remained at follow-up of 1 to 5 years (OR 6.7, 95% CI 2.8-15.7 for RCT, and OR 15.5, 95% CI 6.6-36.7 for non-RCT). The risk of all-cause mortality at 30 days was not different between the groups in RCT (OR 1.20, 95% CI 0.52-3.16) or non-RCT studies (OR 0.99, 95% CI 0.52-1.87). In studies reporting all-cause mortality at 1 year or more (up to 5 years), mortality did not differ in RCT studies (OR 1.21, 95% CI 0.59-2.51) but was significantly reduced in non-RCT studies (OR 0.54, 95% CI 0.31-0.96). Stroke incidence was not reduced significantly; however, in meta-regression, the risk of stroke decreased significantly with longer follow-up. Other clinical outcomes were similar between groups. Operation time was significantly increased with surgical AF ablation; however, overall impact on length of stay was variable. CONCLUSIONS:: In patients with persistent or permanent AF who present for cardiac surgery, the addition of surgical AF ablation led to a significantly higher rate of sinus rhythm in RCT and non-RCT studies compared with cardiac surgery alone, and this effect remains robust over the longer term (1-5 years). Although non-RCT studies suggest the possibility of reduced risk of stroke and death, this remains to be proven in prospective RCTs with adequate power and follow-up.