JACC: Dabi linked to bleeding, thromboembolic events in AF ablation patients
Much debate surrounds optimal medical therapy options for patients undergoing atrial fibrillation (AF) ablation procedures. In an observational study published online Feb. 1 in the Journal of the American College of Cardiology, researchers recommended dabigatran be studied further after finding the drug was linked to bleeding or thromboembolic complications when compared to warfarin in ablation patients.

“Radiofrequency catheter ablation has brought a paradigm shift to the management of AF and has currently evolved to become the standard of care for symptomatic patients in whom antiarrhythmic drugs have failed,” Dhanunjaya Lakkireddy, MD, of the University of Kansas Hospital and Medical Center in Kansas City, and colleagues wrote. AF ablation procedures are often challenging, and the optimal peri-procedural anticoagulation regiments are still “nonuniform,” they said.

Because much debate surrounds this topic, Lakkireddy and colleagues set out to investigate whether continuing dabigatran (Pradaxa, Boehringer Ingelheim) during the peri-procedural time period of AF ablation was safe and effective. To do so, the researchers performed a multicenter, observational study using a prospective registry of 290 patients who underwent AF ablation for drug-refractory, symptomatic AF at eight electrophysiology labs between January 2010 and July 2011. 

Of the 290 patients, 145 were prescribed peri-procedural dabigatran and an equal number of patients were on warfarin. Seventy-nine percent of patients were male and 57 percent were reported to have paroxysmal AF.

The researchers reported three cases of thromboembolic complications in the nonparoxysmal dabigatran group compared with no complications in those patients taking uninterrupted peri-procedural warfarin. Patients in the dabigatran arm also saw higher rates of major bleeds, 6 percent  vs. 1 percent in the warfarin arm. Total bleeding rates were 14 percent for those in the dabigatran arm and 6 percent for those in the warfarin arm.

The composite of bleeding and thromboembolic complications occurred in 16 percent of dabigatran patients and 6 percent of warfarin patients. The authors noted that dabigatran was an independent predictor of bleeding or thromboembolic complications. Additionally, patients older than the age of 75 also had higher risk of developing bleeding.

“Dabigatran at a dose of 150 mg twice daily has been shown to be better than warfarin in preventing stroke in AF patients with an equivalent bleeding risk and has recently been approved for use in the United States for nonvalvular AF,” the researchers wrote.

“The incidence of thromboembolic complications in nonparoxysmal AF patients in the dabigatran group, although not statistically different from that of the warfarin group, was very high (5 percent) and probably has important clinical relevance.” The researchers said that this may be due to the extent of ablation in persistent AF.

The authors noted that holding dabigatran in patients for more than 24 hours without delaying the first dose post-procedure may decrease bleeding events; however, the researchers noted that this notion must be investigated in future clinical trials.

“In patients undergoing AF ablation, continuation of dabigatran during the peri-procedural period is associated with an increased risk of bleeding and composite of bleeding or embolic complications compared with uninterrupted warfarin therapy,” the authors summed.

The optimal strategies to treat ablation patients periprocedurally are still unknown and future randomized trials are necessary to confirm the best approach.