Expert Review: Arrhythmia

Feasibility and safety of dabigatran versus warfarin for periprocedural anticoagulation in patients undergoing radiofrequency ablation for atrial fibrillation: Results from a multicenter prospective registry.

Background

Radiofrequency catheter ablation of atrial fibrillation (AF) is evolving as a standard therapeutic procedure for both paroxysmal and persistent forms of this arrhythmia. It is obvious for many reasons that this invasive procedure – which is performed more and more frequently – is accompanied by an increased risk of thromboembolic complications, and therefore it needs a safe peri-procedural anticoagulation. This is achieved with various non-uniform therapeutic protocols but the most convenient seems to be simply keeping the current oral anticoagulation with warfarin targeting for an INR of 2.0-3.0.

Knowledge Gap

Warfarin is no longer the sole drug that can be used for chronic oral anticoagulation in patients with AF, with dabigatran proven to be non-inferior or even superior in terms of reduction of both thromboembolic and bleeding risks. Consequently increasing numbers of patients with AF are likely to be treated with dabigatran, raising the reasonable question of whether this therapy may be as protective as warfarin during AF ablation.

Aim of the Study

In the present study the authors evaluated the efficacy and safety of peri-procedural dabigatran use in comparison with warfarin during AF ablation.
Methods

This was a multi-center, observational study from a prospective registry which compared 290 AF ablation patients from eight high-volume centers in the United States (145 treated with 150 mg dabigatran b.i.d. for at least one month vs. 145 under uninterrupted warfarin therapy over the same period targeting an INR of 2.0-3.5).

All patients treated with dabigatran were matched for gender, age and type of AF with patients under warfarin therapy. Dabigatran dose was withheld in the morning of the procedure and was resumed within 3 hours after hemostasis and when the patient was able to take the drug orally.
Results

The mean age in both groups was 60 years with 79% of study participants being males; 57% had paroxysmal AF. Both groups had a similar CHADS2 score, left atrial size, and left ventricular ejection fraction. Three thromboembolic complications (2.1%) occurred in the dabigatran group compared with none in the warfarin group (p = 0.250). The dabigatran group had a significantly higher major bleeding rate (6% vs. 1%; p = 0.019), total bleeding rate (14% vs. 6%; p = 0.031), and composite of bleeding and thromboembolic complications (16% vs. 6%; p = 0.009) compared with the warfarin group. Dabigatran use was confirmed as an independent predictor of bleeding or thromboembolic complications (odds ratio: 2.76, 95% CI: 1.22 to 6.25; p = 0.01) on multivariate regression analysis.
Conclusion

In patients undergoing AF ablation, peri-procedural dabigatran use significantly increases the risk of bleeding or thromboembolic complications compared with uninterrupted warfarin therapy.
Perspective – Clinical Impact

In terms of this conclusion it can be speculated that patients who are chronically treated with dabigatran instead of warfarin should not undergo AF ablation. The fact that both thromboembolic and bleeding risks are increased after dabigatran withdrawal at a time earlier than the recommended 24-48 hours before an invasive procedure remains unexplained. For practice it is too early to draw a definitive conclusion concerning the optimal anticoagulation during AF ablation without a large scale randomized controlled study comparing dabigatran with warfarin.

 

Corresponding Author from the original paper: Dr. Dhanunjaya Lakkireddy, Electrophysiology Research, KU Cardiovascular Research Institute, 3901 Rainbow Boulevard, MS 4023, Kansas City, Kansas 66160-7200. E-mail: dlakkireddy@mac.md.

Citation: J Am Coll Cardiol 2012; 59: 1168-1174

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