CHAMPION-AF
Left Atrial Appendage Closure vs NOACs as First-Line Therapy for Stroke Risk Reduction in Atrial Fibrillation
Presented by Saibal Kar — Los Robles Hospital
Subspecialty: Atrial Fibrillation
Published in NEJM
Key Result
WATCHMAN FLX LAAC was non-inferior to NOACs for stroke prevention (5.7% vs 4.8% composite CV death/stroke/embolism at 3 years) and statistically superior for safety, with 43% less non-procedural major bleeding (10.9% vs 19.0%). Net clinical benefit favored the device (15.1% vs 21.8%).
What did this trial find?
CHAMPION-AF randomized 3,000 patients with non-valvular atrial fibrillation eligible for anticoagulation to WATCHMAN FLX left atrial appendage closure vs. NOACs. At 3 years, LAAC was noninferior for the composite of CV death, stroke, and systemic embolism (5.7% vs. 4.8%) and superior for non-procedural bleeding (10.9% vs. 19.0%). However, ischemic strokes were numerically higher with the device (3.2% vs. 2.0%). There is substantial controversy: the NEJM editorialist and prominent commentators argue the noninferiority margin was lenient, event rates were lower than expected, and the data do not justify replacing NOACs broadly, especially in light of the negative CLOSURE-AF trial. Trial investigators and the sponsor frame the results as supporting LAAC as a first-line alternative via shared decision-making.
Why does this trial matter?
Real controversy. This trial has generated a genuinely polarized debate. The NEJM editorialist (Marcus) explicitly stated the trial did not convincingly prove device equivalence, citing lenient noninferiority margins and the shadow of the negative CLOSURE-AF trial. Mandrola published a prominent six-point takedown arguing the trial was 'designed to be positive.' Meanwhile, trial investigators and the sponsor frame the results as practice-changing. The numerically higher ischemic stroke rate with the device (3.2% vs. 2.0%), the selective exclusion of procedural bleeding from the primary safety endpoint, and the industry funding all fuel meaningful interpretive disagreement. This is not straightforward coverage — it is a contested trial with substantive, well-credentialed critics.
Study Design
Multinational, randomized controlled trial across 141 sites in 4 countries
Clinical Implications
LAAC with WATCHMAN FLX is a reasonable first-line alternative to long-term anticoagulation for stroke prevention in AF, offering similar efficacy with significantly less bleeding. This expands the eligible population beyond patients who are NOAC-intolerant.
Abstract
The CHAMPION-AF trial was a multinational, randomized controlled trial evaluating the WATCHMAN FLX left atrial appendage closure (LAAC) device versus non-vitamin K antagonist oral anticoagulants (NOACs) as first-line therapy for stroke risk reduction in patients with non-valvular atrial fibrillation. The trial enrolled 3,000 patients across 141 sites in the US, Germany, Japan, and the UK, with a mean age of 71 years and mean CHA2DS2-VASc score of 3.5. Procedural success for device implantation was 99%. At 3 years, the primary efficacy endpoint of cardiovascular death, stroke, and systemic embolism occurred in 5.7% of the device group versus 4.8% in the NOAC group, meeting the pre-specified non-inferiority margin. The primary safety endpoint demonstrated statistical superiority for the device: non-procedural major bleeding occurred in 10.9% vs 19.0% (a 43% relative reduction). Including procedural bleeding, the rate was 12.8% vs 19.0% — a 34% relative reduction. The net clinical benefit endpoint (non-procedure-related bleeding and death) favored the device at 15.1% versus 21.8%.