The correct answer is: C) Continue the same dose of dabigatran and stop 24-36 hours prior to the procedure.

Although medical therapy remains the foundation of the treatment of AF, radio frequency ablation (RFA) has become recommended therapy for selected patients, predominantly those with symptomatic paroxysmal AF who have failed treatment with one or more antiarrhythmic drugs, with normal size or mildly dilated atria, normal or mildly reduced ventricular function, and absence of severe pulmonary disease.¹ However, periprocedural anticoagulation remains challenging as the risk of embolic events during the periprocedural time of RFA is increased by about 1-5 %.^2-3

Many patients who undergo AF ablation have an elevated CHADS₂ score, and are already systemically anticoagulated. Until 2009, the only anticoagulants that could be used were vitamin K antagonists (VKAs). Patients historically have had VKA discontinued several days prior to RFA and were bridged with heparin before and after the procedure until VKA was restarted and a therapeutic international normalized ratio (INR) was achieved. However, extensive reports showed better outcomes with the use of continuous or nearly continuous anticoagulation in the periprocedural period, and this has become the accepted approach.^4-5

Currently, newer oral anticoagulants (including one direct thrombin inhibitor and 2 factor Xa inhibitors) are now available in many countries for use in atrial fibrillation. The most studied drug among these new oral anticoagulants in patients undergoing RFA is dabigatran. The use of either VKA or dabigatran in patients with AF for prevention of stroke and systemic thromboembolism are both class I in ACCF/AHA/HRS guidelines.⁶ The majority of studies evaluating dabigatran in AF ablation have shown similar outcomes as compared to warfarin.^7-8 However, special caution is required when switching dabigatran to VKA as it may take one to two weeks (or longer) before a therapeutic INR is achieved due to the slow onset of action of VKAs. Therefore, there is no benefit and it may even be harmful to switch dabigatran to VKA just prior to the procedure.

Although two doses of dabigatran are available in many countries, there is no evidence to support changing the recommended dose of dabigatran in the days prior to AF ablation. However, it is recommended to hold dabigatran 24-36 hours before the procedure and resume dosing the morning after the procedure, with a bridge of intravenous unfractionated heparin starting six hours after hemostasis has been achieved.¹

After the RFA procedure, damage to the left atrial endothelium may serve as a nidus for thrombus formation. Furthermore, it is well recognized that symptomatic or asymptomatic AF may recur after ablation and hence the decision to anticoagulate for a longer term should be based on the risk of stroke. The joint 2012 HRS/EHRA/ECAS expert consensus statement regarding catheter and surgical ablation of atrial fibrillation recommends continuing systemic anticoagulation in all patients for at least two months following a RFA procedure. Decisions to use systemic anticoagulation for greater than two months post-AF ablation should be based on the patient's risk factors for stroke. Continuous ECG monitoring should be performed for high risk patients to screen for asymptomatic atrial fibrillation, atrial flutter, and atrial tachycardia.¹

Studies on other newer oral anticoagulants are ongoing. Recently, uninterrupted rivaroxaban therapy has been reported to be equally safe and efficacious in preventing bleeding and thromboembolic events in patients undergoing RFA, when compared to uninterrupted warfarin.⁹ However, more data are needed before its routine use can be recommended.

References

1. Calkins H, Kuck K, Cappato R, et al. 2012 HRS/EHRA/ECAS Expert Consensus Statement on Catheter and Surgical Ablation of Atrial Fibrillation: Recommendation for Patient Selection, Procedural Technique, Patient Management and Follow-up, Definitions, Endpoints, and Research Trial Design. Heart Rhythm 2012; 9:632-696
2. Spragg DD, Dalal D, Cheema A, et al. Complications of catheter ablation for atrial fibrillation: incidence and predictors. J Cardiovasc Electrophysiol 2008; 19:627
3. Cappto R, Calkins H, Chen SA, et al. Prevalence and causes of fatal outcome in catheter ablation of atrial fibrillation. J Am Coll Cardiol 2009;53: 1798-803.
4. Santangeli P, Di Biase L, Horton R, et al. Ablation of atrial fibrillation under therapeutic warfarin reduces periprocedural complications: evidence from a meta-analysis. Circ Arrythm Electrophysiol 2012; 5:302-11.
5. Kuwahara T, Takahashi A, Takahashi Y, et al. Prevention of periprocedural ischemic stroke and management of hemorrhagic complications in atrial fibrillations ablation under continuous warfarin administration. J Cardiovasc Electrophysiol 2013; 24:510-5.
6. Wann LS, Curtis AB, Ellenbogen KA, et al. 2011 ACCF/AHA/HRS focused update on the management of patients with atrial fibrillation (update on Dabigatran): a report of the American College of Cardiology Foundation/American Heart Association Task Force on practice guidelines. J Am Coll Cardiol 2011;57:1330-1337.
7. Kim JS, She F, Jongnanrangsin K, et al. Dabigatran vs Warfarin for radiofrequency catheter ablation of atrial fibrillation. Heart Rhythm 2013; 10:483
8. Nin T, Sairaku A, Yoshida Y, et al. A randomized controlled trial of dabigatran versus warfarin for periablation anticoagulation in patients undergoing ablation of atrial fibrillation. Pacing Clin Electrophysiol 2013; 36:172-9
9. Lakkireddy D, Reddy YM, Biase LD, et al. Feasibility & Safety of Uninterrupted Rivaroxaban for periprocedural anticoagulation in patients undergoing radiofrequency ablation for atrial fibrillation: results from a multicenter prospective registry ONLINE FIRST. J Am Coll Cardiol 2014; [Epub Ahead of Print].