Boston Scientific’s implantable Watchman Left Atrial Appendage Closure Device finally won FDA approval to become an option to long-term warfarin therapy for high-risk patients with nonvalvular atrial fibrillation.

“We know that up to 40 percent of patients who are eligible for oral anticoagulation do not take it for numerous reasons, highlighting the need for additional treatment options,” said Vivek Reddy, MD, director of the Cardiac Arrhythmia Service at the Mount Sinai Hospital in New York City, in a press release. 

The approval came after an FDA advisory panel in 2014 unanimously voted in favor of the device for safety but split on efficacy. That seemed to leave the Watchman’s future murky.

The approval is based on a Watchman clinical program that consisted of numerous studies, more than 2,400 patients and nearly 6,000 patient-years of follow-up, according to the company. Those trials showed that that Watchman could be implanted safely and reduced the risk of stroke in eligible patients while allowing most of them to discontinue warfarin.

Watchman was the subject of the controversial release of PREVAIL (Watchman LAA Closure Device in Patients With Atrial Fibrillation Versus Long Term Warfarin Therapy) findings when Boston Scientific broke an embargo at the American College of Cardiology meeting in 2013. It announced the study met two of its three primary endpoints. There was a reduction in hemorrhagic stroke compared with warfarin but an increase in perioperative events.

PREVAIL and PROTECT (Watchman Left Atrial Appendage System for Embolic Protection in Patients with Atrial Fibrillation) indicated that while ischemic stroke reduction favored warfarin, the Watchman provided patients with comparable protection against all-cause stroke and statistically better reductions in hemorrhagic stroke, disabling stroke and cardiovascular death compared to warfarin over long-term follow-up.

The Watchman has been available internationally since 2009 and will be available in the U.S. centers involved in the clinical trials and other specialized centers as soon as physicians are trained on the implant procedure, the company said.