Key Points
- CHAMPION-AF is the first prospective, randomized trial to test whether LAA closure is noninferior to NOACs in patients who were candidates to oral anticoagulants irrespective of whether they have undergone prior AFib ablation.
- WATCHMAN FLX was noninferior to NOAC therapy for the 3-year composite of cardiovascular death, stroke, and systemic embolism in patients with nonvalvular atrial fibrillation. No difference in deaths, systemic embolism or hemorrhagic strokes, but slightly more ischemic strokes among those undergoing the LAA closure procedure
- Non–procedure-related bleeding was significantly lower with left atrial appendage closure, occurring in 10.9% versus 19.0% with NOAC therapy.
For years, left atrial appendage closure has largely been framed as a fallback strategy for patients with atrial fibrillation who cannot remain on long term anticoagulation. CHAMPION-AF challenges that view directly, asking whether device-based stroke prevention can compete with NOAC therapy even in patients who are still considered candidates for anticoagulation.
At the 2026 American College of Cardiology (ACC) Scientific Sessions, Dr. Saibal Kar presented the primary results of the CHAMPION-AF trial (NCT04394546), which were simultaneously published in The New England Journal of Medicine. In this ongoing, prospective, international, randomized trial, 3000 patients with nonvalvular atrial fibrillation were assigned 1:1 to device-based left atrial appendage closure with WATCHMAN FLX or to NOAC therapy. The primary efficacy end point was a composite of death from cardiovascular causes, stroke, or systemic embolism at 3 years, tested for noninferiority, and the primary safety end point was non–procedure-related bleeding, tested for superiority.
The trial enrolled a relatively contemporary, lower bleeding risk population. Mean age was 71.7 years, 31.9% of patients were women, the mean CHA2DS2-VASc score was 3.5, and the mean HAS-BLED score was 1.3. Of the 3000 randomized patients, 1499 were assigned to the device group and 1501 to anticoagulation.
At 3 years, the primary efficacy end point occurred in 5.7% of the device group and 4.8% of the anticoagulation group, meeting the criterion for noninferiority (hazard ratio 1.20; 95% CI, 0.87 to 1.66; P<0.001 for noninferiority). Researchers found no difference in deaths, systemic embolism or hemorrhagic strokes, but observed slightly more ischemic strokes among those undergoing the LAA closure procedure (3.2% vs. 2%). Non–procedure-related bleeding occurred in 10.9% of device patients and 19.0% of anticoagulation patients (hazard ratio 0.55; 95% CI, 0.45 to 0.67; P<0.001 for superiority). Net clinical benefit also favored left atrial appendage closure, 15.1% versus 21.8% (hazard ratio 0.66; 95% CI, 0.56 to 0.79).
The central tradeoff was captured neatly in Dr. Kar’s interview, when he noted that after the early procedural period, “once you cross 180 days, you can see the curves diverge in favor of the device arm.” That observation mirrors the broader pattern of CHAMPION-AF, where thromboembolic protection remained within the noninferiority boundary while bleeding increasingly favored the device strategy over time.
Overall, CHAMPION-AF suggests that for selected patients with atrial fibrillation who are eligible for long term anticoagulation, WATCHMAN FLX may no longer be viewed solely as an alternative for the intolerant. Instead, these data support its place in a shared decision-making discussion centered on balancing durable stroke prevention against the cumulative burden of bleeding.