Heart surgery trial finds LAA closure beneficial only for high-risk patients

A small pouch inside the heart has narrowed the promise of a routine surgical add-on. In the LAACS-2 trial, 1,500 patients undergoing planned open-heart surgery were assigned either to closure of the left atrial appendage (LAA) or to standard care, with the appendage left open. After a median 4.0 years, closing it did not significantly reduce stroke or transient ischemic attack across the whole group.

The LAA is a muscular pocket in the heart’s left atrium and a common source of blood clots in people with atrial fibrillation, an irregular heart rhythm. Associate Professor Helena Dominguez of Bispebjerg University Hospital in Copenhagen led the work with colleagues across four sites in Denmark, Spain and Sweden. The study included patients without known atrial fibrillation as well as those with previous paroxysmal or chronic atrial fibrillation; the mean age was 67 years, and 18.5% were female.

The primary outcome occurred in 4.28% of patients who had the appendage closed, compared with 5.04% receiving standard care. The hazard ratio was 0.85, with a 95% confidence interval of 0.53 to 1.37 and p = 0.517. Overall mortality also showed no significant difference. Current ESC Guidelines recommend surgical LAA closure alongside oral anticoagulation for patients with atrial fibrillation undergoing cardiac surgery, but evidence has been less clear for people without a known history of the rhythm disorder.

The signal appeared when researchers separated patients by their starting level of stroke risk. Those with a CHA2DS2-VASc score above the median had a 56% reduction in stroke or transient ischemic attack with LAA closure, with p = 0.018; patients at lower risk saw no significant benefit. Dominguez said the result does not support closing the appendage routinely in all planned cardiac operations, while protection appeared in the highest-risk group. A mechanistic study is continuing, and follow-up of LAACS-2 will continue because the outcome curves diverged over time.

So what changes for patients? Not every person facing open-heart surgery should automatically receive LAA closure on the strength of this trial. The practical lead is more selective: patients with the highest baseline stroke risk may be the group most likely to benefit, while the overall result does not establish a clear advantage for everyone. The conclusion remains a trial finding, not a universal treatment rule.