WATCHMAN FLX Device Meets Primary Safety and Efficacy Endpoints in CHAMPION-AF Trial

Late-breaking findings show the LAAC device provided superior protection from bleeding compared to blood thinners in patients with non-valvular atrial fibrillation.

Mar. 28, 2026 at 4:05pm

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Boston Scientific Corporation announced that the CHAMPION-AF global clinical trial met all primary and secondary safety and efficacy endpoints. The study evaluated the WATCHMAN FLX™ Left Atrial Appendage Closure (LAAC) Device compared to non-vitamin K antagonist oral anticoagulants (NOACs) as a first-line option for stroke risk reduction in patients with non-valvular atrial fibrillation (NVAF).

Why it matters

Atrial fibrillation increases stroke risk by five times compared to people with a normal heart rhythm. The WATCHMAN technology is designed to permanently close off the left atrial appendage, providing an alternative to long-term blood thinners for stroke risk reduction in patients with NVAF.

The details

At 36 months, the WATCHMAN FLX device was statistically superior to NOACs for non-procedural major and clinically relevant non-major bleeding, achieving a 45% relative reduction in non-procedural bleeding risk. The device also demonstrated statistical non-inferiority to NOACs for the primary efficacy endpoint of stroke, cardiovascular or unexplained death, or systemic embolism.

  • The CHAMPION-AF trial enrolled 3,000 patients with NVAF across 141 sites in the U.S., Canada, Europe, Japan and Australia.
  • Patient follow-up in the CHAMPION-AF trial will continue through five years and will include additional primary and secondary endpoints.

The players

Boston Scientific Corporation

A global medical technology leader that transforms lives through innovative medical technologies.

Martin Leon, M.D.

Study co-chair and Mallah Family professor of cardiology, chief innovation officer and director, Cardiovascular Data Science Center, Columbia University Medical Center.

Brad Sutton, M.D.

Chief medical officer, Atrial Fibrillation Solutions, Boston Scientific.

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What they’re saying

“The success of the landmark CHAMPION-AF trial represents a meaningful milestone that will undoubtedly transform the treatment approach to stroke risk reduction in a broader population of patients who historically have needed to rely on medication.”

— Martin Leon, M.D., Study co-chair and Mallah Family professor of cardiology, chief innovation officer and director, Cardiovascular Data Science Center, Columbia University Medical Center

“These positive data, which have the potential to support updated clinical guidelines globally, will be used in our submission to expand the indication and coverage for the well-established WATCHMAN platform as a first-line stroke risk reduction option, providing physicians with more choices in care for a wider range of patients who have atrial fibrillation.”

— Brad Sutton, M.D., Chief medical officer, Atrial Fibrillation Solutions, Boston Scientific

What’s next

Patient follow-up in the CHAMPION-AF trial will continue through five years and will include additional primary and secondary endpoints.

The takeaway

The CHAMPION-AF trial results demonstrate the WATCHMAN FLX device as a viable first-line treatment option for stroke risk reduction in patients with non-valvular atrial fibrillation, providing superior protection from bleeding compared to blood thinners.