DENVER — Keeping warfarin (Coumadin) on board for an atrial fibrillation ablation procedure is safer than bridging with heparin, a randomized trial showed.

Peri-procedural thromboembolic events were nine times more common with heparin bridging than with uninterrupted warfarin after adjusting for other factors, making it a stronger predictor than even the CHADS2 risk score in the COMPARE trial (P=0.002).

The stroke rate was just 0.25% on uninterrupted anticoagulation compared with 3.7% on heparin bridging (P<0.001), Luigi Di Biase, MD, PhD, Texas Cardiac Arrhythmia Institute at St. David’s Medical Center in Austin, and colleagues found.

Bleeding complications also all favored continuation of warfarin, although only a significant difference for the most common of these events.

Minor bleeding occurred in 4% of the warfarin group versus 22% in the bridged group, an 81% relative difference (P<0.001), the researchers reported at a late-breaking session here at the Heart Rhythm Society meeting.

Newer guidelines from U.S. and European electrophysiology and cardiology groups already suggest that uninterrupted warfarin should be considered for patients getting ablation procedures but based on observational single center data.

“There’s been a natural hesitancy to proceed with procedures during full dose warfarin,” acknowledged David E. Haines, MD, director of the Heart Rhythm Center at William Beaumont Hospital in Royal Oak, Mich.

However, the mechanism of the drugs might explain the seemingly counterintuitive results of this study and similar findings in the device implantation setting in a second trial presented at the same session, he noted in an interview with MedPage Today.

Heparin has both an anticoagulant and antiplatelet effect, whereas warfarin has little impact on platelets.

“Hemostasis is much more dependent on good platelet function,” Haines explained.

The peaks and valleys in antithrombotic coverage caused by bridging may also contribute, Patrick T. Ellinor, MD, PhD, an electrophysiologist at the Massachusetts General Institute for Heart, Vascular and Stroke Care in Boston, added in an interview.

Although his center has already adopted the strategy, he predicted that others that haven’t will now.

“Although it was open-label, it’s still a really large study and I think it will have an immediate impact on clinical care,” he said. “It’s going to be the standard of care after today.”

The multicenter COMPARE trial included 1,584 patients with nonvalvular atrial fibrillation who were at high risk of thromboembolic events with well-managed warfarin levels in the month or so prior to enrollment.

Source: MedPage Today.