Chicago, IL—In patients with atrial fibrillation (AF) who underwent catheter ablation, the new anticoagulant dabigatran (Pradaxa), an oral direct thrombin inhibitor, was found to effectively prevent thromboembolic events in a small prospective study presented by Charlotte Eitel, MD, Department of Electrophysiology, Heart Center Leipzig, Germany, at the 2012 American College of Cardiology meeting. Patients with AF are known to be at increased risk for thromboembolic events.
Dr Eitel and colleagues conducted this study from July 2010 to September 2011 to determine the longer-term safety and efficacy of dabigatran in this setting, because existing evidence with postablation dabigatran was limited to a small, 30-day study.
A total of 89 patients with AF (average age, 63 years) were prospectively started therapy with dabigatran the evening of their catheter ablation, if permitted by the status of the femoral puncture site, or with low-molecularweight heparin until dabigatran could be started. Renal insufficiency was a study exclusion criterion.
The results of the serial 7-day Holter electrocardiograms and CHA2DS2-VASc score drove the decision about whether to continue anticoagulation. The average follow-up was 274 days (interquartile range, 59, 497).
Twice-daily dabigatran was given at 110-mg doses to 78% and at 150-mg doses to 22% of study patients, respectively. Paroxysmal AF was found in 57% of the study patients (78% men). The left atrial parasternal long axis diameter was 42 mm.
The study patients had an intermediate risk of thromboembolic events with an average CHA2DS2-VASc score of 2 (interquartile range, 0, 5) and low risk of bleeding with a HAS-BLED (hypertension, abnormal renal/liver function, stroke, bleeding history or predisposition, labile international normalized ratio, elderly [> 65 years], drugs/alcohol concomitantly) score of 1 (interquartile range, 0, 3).
In terms of AF-related findings, recurrences of arrhythmia were found in 34%, 25%, and 21% of patients at their 3-month, 6-month, and 12-month clinical follow-ups, respectively. Because of arrhythmia recurrence, 9 patients required electrical cardioversion. Transesophageal echocardiography was required in only 1 patient, because of the discontinuation of dabigatran.
The investigators reported that the effectiveness of this anticoagulation strategy was shown by the lack of any prespecified clinical events of stroke and systemic embolism at the mid-term follow-up. Safety was identified by no occurrence of minor or major hemorrhage. Patient acceptance of anticoagulation with dabigatran was high.
The investigators stated that anticoagulation with dabigatran in patients with AF who underwent catheter ablation was an “attractive alternative to the conventional approach with warfarin” because of its predictable dose–response relationship.
In addition, this strategy does not require laboratory monitoring, whereas warfarin use does.