Clinical Question

Does surgical left atrial appendage occlusion reduce the risk of stroke in patients with atrial fibrillation?

Bottom Line

Surgical closure of the left atrial appendage during cardiac surgery for another reason safely reduces the risk of ischemic stroke (number needed to treat = 43 over four years). Because the risk of stroke in the first 30 days after any cardiac surgery is approximately 2% and the absolute reduction in the risk of stroke with the procedure was approximately 2%, performing this procedure in patients who are not already undergoing cardiac surgery is not ideal. (Level of Evidence = 1b)

Synopsis

Left atrial appendage occlusion to reduce the risk of stroke caused by atrial fibrillation is sometimes performed as an adjunct procedure for someone who is undergoing cardiac surgery for another indication. The procedure has never been subjected to a randomized controlled trial. The researchers identified 4,770 adults with atrial fibrillation and a CHA₂DS₂VASc (congestive heart failure; hypertension; age 75 years or older [doubled]; diabetes mellitus; prior stroke, transient ischemic attack, or thromboembolism [doubled]; vascular disease) score of 2 or higher (mean = 4.2), indicating an elevated risk of stroke. The mean age was 71 years, 67% were men, and slightly more than one-half had permanent or persistent atrial fibrillation. Approximately one-half of the patients were receiving an oral anticoagulant at baseline. A total of 92.1% received the intervention in the treatment group, compared with 5% in the control group.

Allocation was properly concealed, and the patients, their care teams (other than the surgeons), and outcome assessors were masked to the treatment assignment. Groups were balanced at the start of the study, and analysis was by intention to treat. Patients were followed up for a mean of 3.8 years, and the trial was stopped early by a data and safety monitoring committee. Ischemic stroke occurred significantly less often in the intervention group (4.6% vs. 6.9%; hazard ratio = 0.66; 95% CI, 0.52 to 0.84; number needed to treat = 43); the reduction in risk of any stroke was similar between groups, and most of the benefit occurred beyond 30 days from the day of surgery. There was no significant difference between groups in all-cause mortality, hospitalization for heart failure, major bleeding, or myocardial infarction. Subgroup analyses revealed no clear differences by age, sex, use of anticoagulation, or other factors.

Study design: Randomized controlled trial (double-blinded)

Funding source: Foundation

Allocation: Concealed

Setting: Inpatient (any location) with outpatient follow-up

Reference: Whitlock RP, Belley-Cote EP, Paparella D, et al.; LAAOS III Investigators. Left atrial appendage occlusion during cardiac surgery to prevent stroke. N Engl J Med. 2021;384(22):2081–2091.

Editor's Note: Dr. Ebell is deputy editor for evidence-based medicine for AFP and cofounder and editor-in-chief of Essential Evidence Plus, published by Wiley-Blackwell.