Watchman FLX Matches DOACs in AF but Raises Questions

In the CHAMPION-AF trial, Watchman FLX LAAO was noninferior to DOACs for the composite of CV death, stroke, or systemic embolism at 3 years in AF patients eligible for long-term anticoagulation (5.7% vs 4.8%; difference 0.9%). It also cut non-procedure-related bleeding (10.9% vs 19.0%), though overall ISTH major bleeding rates were similar when including periprocedural events. Results were presented at ACC.26 and published in NEJM.

Trial details

The study randomized 3,000 patients (mean CHA2DS2-VASc 3.5) at 141 sites to Watchman FLX or DOAC. Successful implant occurred in 92.5%, with effective closure in 98.6% at 4 months. Post-implant antithrombotics transitioned to single antiplatelet therapy after 3 months. DOAC adherence was 87%, with 13.7% crossover to LAAO.

Safety and efficacy

Non-procedure-related bleeding favored LAAO, but ischemic stroke or systemic embolism was numerically higher (3.2% vs 2.2%). CV death was identical (2.7%). Device issues included pericardial effusion (0.7%), DRT (4.8%), and procedure-related serious events (2.3%). A net clinical benefit endpoint (including non-procedure bleeding) showed superiority for LAAO (15.1% vs 21.8%).

Clinical debate

Experts debated the wide noninferiority margin (4.8%), low event rates below powering assumptions, more ischemic strokes in LAAO, and selective bleeding endpoint. It contrasts with CLOSURE-AF, which favored medical therapy in high-bleed-risk patients. LAAO may suit shared decision-making for suitable AF patients, but not as first-line replacement for DOACs in all. Upcoming CATALYST and 5-year CHAMPION-AF data will add clarity.