Left atrial appendage occlusion may reduce ischaemic stroke risk in AF

Left atrial appendage occlusion (LAAO) added to usual care led to a reduction in ischaemic stroke or non-cerebral systemic embolism following cardiac surgery among patients with atrial fibrillation (AF), according to results of the LAAOS* III trial.

“Surgical LAAO reduce[d] ischaemic stroke by 33 percent [and by 42 percent] after the first 30 perioperative days,” presented study lead author Professor Richard Whitlock from McMaster University, Ontario, Canada, at ACC.21.

“We were ecstatic to see these results. This is a procedure that’s done once, and it keeps giving a benefit over time. This is going to prevent thousands of strokes,” he added.

Participants in this multinational (105 centres in 27 countries) study were 4,811 adults (mean age 71 years, 67.5 percent male) with a history of AF or flutter who were undergoing surgery for a different cardiac indication and had a CHA₂DS₂-VASc score of ≥2 (mean 4.2). They were randomized 1:1 to undergo surgical LAAO** or not at time of surgery. Antithrombotic therapy was continued, and patients were followed up every 6 months for a median 3 years, with 76.8 percent of patients remaining on anticoagulant therapy over this period. Ninety-two percent of patients underwent the assigned procedure.

Sixty-seven and 21 percent of patients underwent valve replacement and isolated coronary artery bypass graft, respectively. About half were on oral anticoagulants at baseline. Mean cardiopulmonary bypass time was slightly longer in the LAAO vs non-LAAO group (119 vs 113 minutes; p<0.001), as was mean cross clamp time (86 vs 82 minutes; p<0.001), while fewer patients in the LAAO group had prolonged heart failure hospitalization (HFH; n=5 vs 14; p=0.04).

At a mean 3.8-years follow-up, the composite of ischaemic stroke or non-cerebral systemic embolism was significantly lower among patients who did vs did not undergo LAAO*** (4.8 percent vs 7.0 percent; hazard ratio [HR], 0.67, 95 percent confidence interval [CI], 0.53–0.85; p=0.001). [ACC.21, abstract 21-LB-21375-ACC; N Engl J Med 2021;doi:10.1056/NEJMoa2101897]

The number of LAAOs during cardiac surgery needed to prevent one stroke at 5 years was 37.

The results were consistently in favour of LAAO across multiple subgroups including sex, age, history of rheumatic heart disease, heart failure, stroke, or hypertension, type of surgery or anticoagulant, left ventricular ejection fraction, and CHA₂DS₂-VASc score.

The reduction was primarily driven by the 34 percent reduction in ischaemic stroke among patients in the LAAO vs non-LAAO group (4.6 percent vs 6.9 percent; HR, 0.66, 95 percent CI, 0.52–0.84). The incidence of systemic embolism was 0.3 percent in both groups (HR, 0.86). Death rate was also comparable between groups (22.6 percent vs 22.5 percent; HR, 1.00), with 1.3 percent of deaths attributed to stroke. HFH occurred in 7.7 and 6.8 percent, respectively (HR, 1.13), major bleeding in 10.4 and 11.2 percent (HR, 0.93), and myocardial infarction in 2.1 and 2.3 percent (HR, 0.87).

A landmark analysis showed an even greater reduction with LAAO 30 days post-surgery (2.7 percent vs 4.6 percent; HR, 0.58) vs the first 30 days post-surgery (2.2 percent vs 2.7 percent; HR, 0.82).

A new indication?

“This study confirms a new paradigm for stroke prevention for patients with AF,” said Whitlock. “The additive benefit of surgical LAAO on top of blood thinners has now been proven. There is no question that patients who are undergoing heart surgery and have elevated stroke risk and AF should have their atrial appendage occluded in their cardiac surgery.”

Despite its benefits for stroke prevention, anticoagulation therapy has multiple drawbacks including incorrect dosing, nonadherence, and the need for medical-related interruptions, the authors said. 

“This trial opens a new option for treatment of these patients by layering a mechanical approach – occlusion – on top of a medical approach. Instead of a tension between anticoagulation and occlusion, we need to start thinking about using these as additive approaches when patients are at high risk for stroke,” said Whitlock.

However, concomitant LAAO is not a substitute for anticoagulation, the authors cautioned.