Global, nonindustry effort
LAAOS III investigators at 105 centers in 27 countries enrolled 4,811 patients undergoing cardiac surgery (mean age, 71 years; 68% male) who had a CHA2DS2-VASc score of at least 2.
In all, 4,770 were randomly assigned to no LAAO or occlusion via the preferred technique of amputation with suture closure of the stump as well as stapler occlusion, or epicardial device closure with the AtriClip (AtriCure) or TigerPaw (Maquet Medical). The treating team, researchers, and patients were blinded to assignment.
Patients were followed every 6 months with a validated stroke questionnaire. The trial was stopped early by the data safety monitoring board after the second interim analysis.
The mean CHA2DS2-VASc score was 4.2, one-third of patients had permanent AFib, 9% had a history of stroke, and more than two-thirds underwent a valve procedure, which makes LAAOS III unique, as many previous trials excluded valvular AFib, Dr. Whitlock pointed out.
Operative outcomes in the LAAO and no-LAAO groups were as follows:
- Bypass time: mean, 119 minutes vs. 113 minutes.
- Cross-clamp time: mean, 86 minutes vs. 82 minutes.
- Chest tube output: median, 520 mL vs. 500 mL.
- Reoperation for bleeding: both, 4.0%.
- Prolonged hospitalization due to HF: 5 vs. 14 events.
- 30-day mortality: 3.7% vs 4.0%.
The primary safety outcome of HF hospitalization at 3.8 years occurred in 7.7% of patients with LAAO and 6.8% without occlusion (HR, 1.13; 95% CI, 0.92-1.40), despite concerns that taking off the appendage could worsen HF risk by impairing renal clearance of salt and water.
“There’s observational data on either side of the fence, so it was an important endpoint that people were concerned about,” Dr. Whitlock told this news organization. “We had a data collection firm dedicated to admission for heart failure to really tease that out and, in the end, we saw no adverse effect.”
Although rates of ischemic stroke at 3.8 years were lower with LAAO than without (4.2% vs. 6.6%; HR, 0.62; 95% CI, 0.48-0.80), there was no difference in systemic embolism (0.3% for both) or death (22.6% vs. 22.5%).
In LAAOS III, fewer than 2% of the deaths were attributed to stroke, which is consistent with large stroke registries, Dr. Whitlock said. “Stroke is not what causes people with atrial fibrillation to die; it’s actually the progression on to heart failure.”
The positive effect on stroke was consistent across all subgroups, including sex, age, rheumatic heart disease, type of OAC at baseline, CHA2DS2-VASc score (≤4 vs. >4), type of surgery, history of heart failure or hypertension, and prior stroke/transient ischemic attack/systemic embolism.
Dr. Anne B. Curtis
Panelist Anne B. Curtis, MD, State University of New York at Buffalo, expressed surprise that about half of patients at baseline were not receiving anticoagulation and questioned whether event rates varied among those who did and didn’t stay on OAC.
Dr. Whitlock noted that OAC is often underused in AFib and that analyses showed the effects were consistent whether patients were on or off anticoagulants.
The study was sponsored by the Population Health Research Institute, McMaster University. Dr. Whitlock reported no relevant disclosures. Dr. Curtis reported consultant fees/honoraria from Abbott, Janssen, Medtronic, Milestone Pharmaceuticals, and Sanofi Aventis, and data safety monitoring board participation for Medtronic.
A version of this article first appeared on Medscape.com.