Safety and efficacy of novel oral anticoagulants in the setting of atrial fibrillation ablation: Is it time to celebrate the “funeral” of warfarin?

Periprocedural stroke, transient ischemic attack (TIA), other significant manifestation of embolizations, and bleeding represent the bulk of the complications that may occur at the time of catheter ablation (CA) for atrial fibrillation (AF) [1–3]. Irrespective of their thrombotic risk score, patients scheduled to undergo CA for AF have usually been receiving oral anticoagulation prior to and immediately after the procedure. The recently published COMPARE randomized trial [4] has shown the superiority of uninterrupted oral anticoagulation strategies with warfarin versus interrupted strategies in reducing the periprocedural risk of TIA/stroke and, interestingly, also reducing the rate of minor bleeding. The trial [4] clearly showed that careful periprocedural anticoagulation management is essential to reduce these complications especially in patients with non-paroxysmal AF. Our group described another important outcome of uninterrupted anticoagulation strategies with warfarin, which is the reduction of “silent cerebral ischemia” (SCI) detected with diffused magnetic resonance brain imaging [5]. Uninterrupted warfarin strategies, ACT levels above 300 seconds, and administration of a pre-transseptal heparin bolus are important practices to reduce the rate of this asymptomatic complication (SCI), while further investigation establishes its clinical relevance [5]. Can all these data be applied to the novel oral anticoagulants recently introduced into the market for stroke risk prevention of patients with non-valvular atrial fibrillation undergoing catheter ablation procedures? Since none of these agents have yet been tested in a randomized controlled fashion in the setting of catheter ablation for atrial fibrillation, no strict recommendation should be made at this time. Data comparing uninterrupted dabigatran versus warfarin have shown contrasting results and have included mainly paroxysmal AF patients [6–11]. When non-paroxysmal AF patients have been included, uninterrupted dabigatran use seemed to be inferior when compared to the uninterrupted warfarin use in protecting against TIA/stroke [12, 13]. On the other hand, the uninterrupted use of rivaroxaban and apixaban has shown non-inferiority to warfarin in their thromboembolic protecting role, but again, these studies were not randomized [14, 15]. In addition, it is also important to note that in all these studies with the uninterrupted use of the novel oral anticoagulants, a few effusions occurred and all were treated without dramatic sequelae. These data although important arise from non-randomized series. Until a reversal agent for these new drugs will become available, recommendations in the settings of AF ablation should be made only after the results of randomized trials testing the safety of these new drugs. In this issue of the journal, Naccarelli et al. [16] presents the rationale and study design of the “Venture AF trial,” the first randomized, open-label, active-controlled multicenter study with the aim to evaluate the safety of uninterrupted rivaroxaban versus warfarin in patients undergoing catheter ablation for AF. The study will enroll and randomize approximately 250 subjects with paroxysmal or persistent AF. The primary end point will be the incidence of postprocedure major bleeding while the secondary end points will include L. Di Biase (*) Albert Einstein College of Medicine at Montefiore Hospital, New York, USA e-mail: dibbia@gmail.com