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After a decade of rocky data releases and regulatory rejections, the Watchman left atrial appendage closure device finally got an indication for stroke risk reduction in non-valvular atrial fibrillation.
But while device maker Boston Scientific highlighted that it's the "first-of-its-kind alternative to long-term warfarin" (Coumadin) in announcing the approval, the indication was only for patients who would be suitable candidates for warfarin but who "have an appropriate rationale to seek a non-pharmacologic alternative to warfarin."
Just what might count as an appropriate rationale was not spelled out .
Only centers already experienced with transcatheter delivery of the device through its clinical studies will get access, with availability spreading to additional specialized centers as physicians are trained in on the procedure, according to Boston Scientific.
Patients are to be selected by elevated thromboembolic risk score (CHADS2 or CHA2DS2-VASc) after weighing the safety and effectiveness of the device versus warfarin.
The approval went against the recommendations of the most recent FDA advisory committee to consider it, with a 7-6 vote coming down against approval in 2014, mainly over questions of efficacy.
A 2009 FDA advisory committee had voted 7-5 for approval, but the agency issued a not-approvable letter. It required further safety data after the PROTECT-AF trial showed noninferior efficacy to warfarin but substantially more bleeding and procedure-related complications.
While the subsequent PREVAIL trial's early results led a 2013 FDA advisory committee to vote 13-1 in favor of approval, the final analysis failed on the primary overall efficacy endpoint of noninferiority to warfarin for stroke, systemic embolism, or cardiovascular or unexplained death. It did meet two other primary safety and embolic prevention noninferiority endpoints.
Meta-analysis of the two trials together favored warfarin for ischemic stroke protection but showed similar prevention of all-cause stroke and better reduction in hemorrhagic stroke, disabling stroke, and cardiovascular death with the device long-term, according to Boston Scientific, citing unpublished data.
The approval was announced during the American College of Cardiology annual meeting -- notable, given that presentation of the PREVAIL trial data was cancelled last minute at the same conference 2 years ago due to an embargo break by Boston Scientific.
From the American Heart Association: