We read the study by Sardar et al entitled Meta-Analysis of Risk of Stroke or Transient Ischemic Attack With Dabigatran for Atrial Fibrillation Ablation .

Sardar et al have conducted a rigorous systematic review and meta-analysis on the risk of stroke and transient ischemic attack with the use of dabigatran in catheter ablation (CA) of atrial fibrillation (AF) in comparison to warfarin. They have reported higher risk of thromboembolic events (including stroke and transient ischemic attack) with the periprocedural use of dabigatran contrary to several other meta-analyses that have shown no statistically significant difference in the risk of thromboembolic events.

Sardar et al attributed their finding of increased risk of stroke and transient ischemic attack, which other meta-analyses have failed to show, to inclusion of a larger number of studies and use of appropriate statistical methods. While the meta-analysis was comprehensive and included the largest series of studies on this topic, Sardar et al used Peto odds ratio to report the overall effect estimate of the thromboembolic outcome. Although, Peto odds ratio has been found to be one of the most powerful methods with the least amount of bias for calculation of outcomes with low event rates, for this method to perform well certain criteria are required, including experimental and control groups having equal number of participants, which is not the case in most of the studies included in their meta-analysis. Given the difficulty of fulfilling all the criteria, Peto odds ratio is not the preferred approach as recommended by Cochrane Handbook for Systematic Reviews of Interventions .

One possible explanation for the higher observed risk is the duration of hold of dabigatran. Many included studies in the meta-analysis by Sardar et al held dabigatran for >2 doses before the procedure and/or resumed it a day after the procedure, which potentially could explain the higher observed risk of thromboembolic events. In our meta-analysis, we included only studies in which dabigatran was held for no more than 2 doses and was resumed the day of the procedure to minimize interruption of anticoagulation; there was no statistically significant difference in the bleeding or thromboembolic events between dabigatran and warfarin in CA of AF.

Given the limitations of the currently available evidence, the growing interest in CA of AF, and the increasing use of the new anticoagulants including dabigatran, large randomized clinical trials are urgently needed to define the role of these medications in CA of AF.