CHAMPION-AF was a prospective, randomized, open-label, noninferiority trial comparing percutaneous left atrial appendage closure (LAAC) with the WATCHMAN FLX device versus guideline recommended DOAC therapy. Patients with nonvalvular atrial fibrillation, increased stroke risk (CHA₂DS₂-VASc ≥2) and no clear contraindication to oral anticoagulation were enrolled across 141 international centers and randomized in a 1:1 fashion.
The primary efficacy endpoint was a composite of cardiovascular death, stroke, or systemic embolism at 3 years, tested for noninferiority with a prespecified margin of 4.8 percentage point. The primary safety endpoint focused on non procedural ISTH major or clinically relevant non-major bleeding events, with blinded endpoint adjudication. Follow up was planned for 36 months, with extended observation to five years.
A total of 3,000 patients were randomized (1,499 LAAC; 1,501 DOACs), with a median follow up of three years. The primary efficacy endpoint (cardiovascular death, any stroke, or systemic embolism) occurred in 5.7% of patients in the LAAC group and 4.8% in the DOAC group, thereby meeting the pre-specified criterion for non inferiority.
Non-procedural ISTH bleeding was significantly lower after LAAC (10.9% vs. 19.0% DOACs; p<0.001), fulfilling the primary safety endpoint in favor of the device strategy.
At the same time, ischemic stroke or systemic embolism occurred numerically more often in the LAAC group (3.2% vs. 2.2%), while cardiovascular mortality was identical in both groups (2.7%). Overall event rates remained low in both arms.
“The Watchman FLX left atrial appendage closure device may be considered as an alternative to NOACs in a shared decision-making process with atrial fibrillation patients who are deemed suitable for long-term oral anticoagulants.”
Prof. Saibal Kar
These results provide important randomized data on the role of LAAC in a population eligible for long-term anticoagulation and suggest that LAAC can achieve outcomes broadly comparable to DOAC therapy for the composite endpoint, while reducing non-procedural bleeding.
However, the findings should be interpreted with caution. The relatively wide noninferiority margin, the numerical excess of ischemic stroke in the device arm, and the exclusion of procedural complications from the primary safety endpoint limit the strength of conclusions regarding overall equivalence. In addition, the studied population had a relatively low baseline bleeding risk.
In the context of current guidelines, these data do not support replacing guideline-recommended DOAC therapy as standard of care. Rather, CHAMPION-AF supports a more individualized approach, in which LAAC may be considered a reasonable alternative in selected patients within a shared decision-making process.
