Catheter ablation is increasingly being performed for patients with paroxysmal and persistent atrial fibrillation (AF). Atrial fibrillation ablation carries a significant risk of thromboembolism and bleeding due to thrombus formation in the left atrium and intraprocedural conversion from AF to sinus rhythm. Multiple strategies are commonly employed peri-AF ablation to reduce the risk of thromboembolic complications, including the use of transesophageal echocardiography, intracardiac echocardiography, irrigated ablation catheters, and intraprocedural anticoagulation. 
Historically, patients treated with vitamin k antagonists (VKA) would typically discontinue this medication and be bridged with low-molecular-weight heparin prior to ablation. However, recent recommendations state that patients undergoing an AF ablation can safely undergo the procedure without discontinuation. 
Direct oral anticoagulants (DOACs), have emerged as an increasingly common therapy for thromboembolism prevention in AF. However, strategies for its use in the setting of AF ablation have been varied and may be associated with an increased incidence of thromboembolism. 
A recent multicenter study published in The American Journal of Cardiology evaluated the safety and efficacy of uninterrupted apixaban versus warfarin anticoagulation in the periprocedural AF ablation setting.  There were no thromboembolic events in the apixaban group or the VKA group. There were no significant differences observed in major bleeding endpoints, minor bleeding, pericardial effusion or groin hematoma. Interestingly, the heparin requirement was the same for both warfarin and apixaban; however, while the periprocedural activated clotting time (ACT) in warfarin group was significant, minimum ACT throughout AF ablation was lower. This might suggest that periprocedural apixaban anticoagulation leads to a more consistent ACT in this setting.
Similar comparisons have been made with other DOACs, although study protocols may differ slightly and there is no direct comparison to assess the role, safety and efficacy of each DOAC. There has been conflicting data, with Steinberg et al,  and Sardar et al,  demonstrating an increase in neurologic complications with dabigatran compared to VKA. This is contrary to the meta-analysis conducted by Honhloser et al,  and Providencia et al,  who demonstrated no significant differences in the composite of neurologic and bleeding complications between the dabigatran and uninterrupted VKA groups.
There is even less data for Rivaroxaban, although results of prospective observational  and randomised  trials with uninterrupted rivaroxaban suggest that this therapy appears to be as safe and efficacious in preventing bleeding and thromboembolic events in patients undergoing AF ablation as uninterrupted warfarin therapy.
More recent data from the RE-CIRCUIT (no increase in thromboembolic endpoints; major bleeding reduction with uninterrupted dabigatran) and AEIOU (no differences in thromboembolic or bleeding endpoints with apixaban-either uninterrupted or interrupted by a single dose- or warfarin) trials are also reassuring, and reinforce that in the near future catheter ablation could possibly move towards uninterrupted DOAC anticoagulation to prevent the difficulties with variable INRs.
However, one must emphasize the need for more information to guide the periprocedural use of both DOACs and VKAs in the real-world setting.
This cardionote was prepared by Dr Amelia Carro-Hevia (Spain) and published simultaneously on Cardio Debate and CardioMaster websites, as part of an ongoing collaboration between the two educational platforms. For more information on Cardiomaster please visit www.cardiomaster.net
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