Published: August 3, 2026
Published in The New England Journal of Medicine and presented at the American College of Cardiology’s scientific meeting, “Left Atrial Appendage Closure or Anticoagulation for Atrial Fibrillation” positions left atrial appendage closure as a viable first-line alternative to long-term oral anticoagulation in eligible patients with nonvalvular atrial fibrillation (A-fib). This publication is a conclusion to a multiyear study effort in which Norton Heart & Vascular Institute served as a clinical trial site contributing to the data used in these findings.
A-fib is among the most prevalent cardiac arrhythmias worldwide. The Centers for Disease Control and Prevention estimates that by 2030, 12.1 million people in the United States will have A-fib. A-fib carries an increased stroke risk compared with normal sinus rhythm. The left atrial appendage (LAA) is the dominant site of thrombus formation in this population — more than 90% of A-fib-related cardiac clots originate there — making it a logical target for stroke risk reduction.
Non-vitamin K oral anticoagulants (NOACs) are the current standard of care for stroke prevention in nonvalvular A-fib (NVAF), but real-world adherence remains a persistent clinical challenge. Approximately 40% of patients with A-fib who are prescribed blood thinners do not take them consistently, significantly increasing their stroke risk. Left atrial appendage closure (LAAC) offers a one-time, implant-based alternative that eliminates ongoing medication dependence.
Prior pivotal trials — including PROTECT-AF and PREVAIL — established the safety and efficacy of LAAC an established it as non-inferior compared to warfarin. CHAMPION-AF evaluated the Watchman FLX device against NOACs in a broad population of patients who are eligible for anticoagulation therapy, a population for which LAAC had not previously been studied at this scale.
CHAMPION-AF was a prospective, randomized, multicenter global investigation designed as a pivotal device study. A total of 1,501 patients were randomized to receive a NOAC at the discretion of the treating physician, and 1,499 were randomized to undergo LAAC with the Watchman FLX device. The trial enrolled a deliberately broad NVAF population, including patients at low-to-moderate bleeding risk — a meaningful expansion beyond the higher-risk profiles typical of earlier LAAC trials.
The primary efficacy endpoint was a composite of ischemic stroke, hemorrhagic stroke, cardiovascular death and systemic embolism. The primary safety endpoint was nonprocedural major bleeding and clinically relevant nonmajor bleeding, assessed by International Society on Thrombosis and Haemostasis criteria. Results were published in March 2026.
Norton Heart & Vascular Institute participated as one of CHAMPION-AF’s global trial sites. Led by principal investigator Kent E. Morris, M.D., MBA, electrophysiologist and the institute’s executive medical director, the site enrolled 14 participants in the study, 13 of whom are currently in active follow-up. (One participant withdrew.) As a pivotal device study that is closed to new participants but remains active, the trial is currently in its fourth year of follow-up, with five-year follow-up calls beginning this fall. Last patient, last visit is anticipated around Sept. 22, 2027.
The team’s participation in CHAMPION-AF reflects the program’s commitment to advancing evidence-based cardiovascular care through clinical investigation — and positions Norton Heart & Vascular Institute as a contributor to what may become a landmark shift in stroke prevention strategy for patients with NVAF.
On the primary efficacy endpoint, Watchman FLX met noninferiority to NOACs. At three years of follow-up, 5.7% of patients in the LAAC group and 4.8% in the NOAC group experienced the composite of ischemic stroke, hemorrhagic stroke, cardiovascular death or systemic embolism — a difference that satisfied the prespecified noninferiority margin.
On the primary safety endpoint, Watchman FLX demonstrated superiority. Nonprocedural major and clinically relevant nonmajor bleeding occurred in 10.9% of the LAAC group versus 19.0% of the NOAC group, representing a 45% relative reduction in bleeding events. This finding is particularly relevant for clinical decision-making, as bleeding risk is often the limiting factor in long-term anticoagulation management.
High implant success rates across 141 global implanting centers reinforce the scalability and procedural reliability of the Watchman FLX platform, an important consideration for programs evaluating broader LAAC adoption.
It is worth noting that CHAMPION-AF’s results exist alongside a more mixed LAAC evidence landscape. CLOSURE-AF, published in the same journal earlier this year, found that LAAC failed to meet the threshold for noninferiority compared with standard care in a population with A-fib and high risks of both stroke and bleeding. The divergence between these two trials reinforces that patient selection remains a determinative factor in LAAC outcomes, and that CHAMPION-AF’s findings apply most directly to the NOAC-eligible population studied.
Taken together, the CHAMPION-AF data support a meaningful shift in how LAAC is positioned within A-fib management. Watchman FLX LAAC may be considered as an alternative to NOACs through a shared decision-making process in patients with A-fib who are deemed suitable for long-term oral anticoagulation.
Candidates likely to benefit most include patients with a history of medication nonadherence, those with bleeding complications or intolerance on anticoagulation, and patients who prefer a durable, nonpharmacologic approach to stroke risk reduction. Clinicians also should weigh procedural considerations in that conversation, including the periprocedural risk window, the potential for peri-device leak, and the postimplant antiplatelet bridging regimen required during the endothelialization period.
As this data is incorporated into future A-fib management guidelines, structural heart programs with established LAAC capability may see expanded referral indications and a shift in how LAAC is introduced — earlier in the treatment conversation rather than as a fallback after anticoagulation failure.