ACC.26 saw an overall drop in research fervor, but one long-awaited study, CHAMPION-AF, spurred a new discussion around the field of left atrial appendage closure and the data we’ve used to justify the procedure.
- Left atrial appendage closure (LAAC) uses an implantable device (like Boston Scientific’s Watchman) to close off a pocket of tissue on the left atrium of the heart.
- This potentially helps patients living with atrial fibrillation to minimize the risk of stroke-causing blood clots that form in the left atrial appendage.
The latest in a long line of LAAC noninferiority trials, CHAMPION-AF set out to answer the question: is the Watchman FLX LAAC device an alternative to oral anticoagulation for stroke prevention?
Researchers randomized 3k patients with a low-bleeding risk and high stroke risk (calculated via CHADSVASC and HAS-BLED) to receive either direct acting OAC or LAAC and followed them for three years.
- The composite primary end-point of stroke, systemic embolism, and CV death occurred in 5.7% of the Watchman group and 4.8% of the OAC group.
- Non-procedure-related bleeding was much lower for LAAC than OAC (10.9% vs. 19.0%).
At first glance, these results seem like a win, and the study’s conclusion asserts that LAAC met the non-inferiority cutoff, but there’s much more to the story.
- Adding CV death to the composite endpoint doesn’t help clarify things, since neither LAAC or OAC affect CV death directly.
- The statistical definition of noninferiority was also more lenient in CHAMPION-AF than the earlier CLOSURE-AF trial, which determined LAAC was not noninferior to OAC.
Speaking of CLOSURE-AF, that trial was funded and designed by the German Center for Cardiovascular Research (a government project), while BSCI directly funded CHAMPION-AF.
Taking it all into consideration, CHAMPION-AF has divided people’s opinions on whether or not an LAAC device is equal to taking medications orally.
- Some physicians hope these results don’t make the procedure more popular while others say it empowers patients to decide for themselves.
- That said, investors saw right through the framing of CHAMPION-AF’s results and BSCI’s stock dropped 10% in the week following the late-breaking publication.
The Takeaway
The average patient doesn’t have the statistical education necessary to interpret the results of CHAMPION-AF, but the average cardiologist does and keeping a critical eye on what is a permanent structural procedure versus a daily pill is key. We still can’t say LAAC is better than OAC, just maybe more convenient.
