Surgical left atrial appendage occlusion in valvular heart disease without atrial fibrillation: the OPINION trial.

Background And Aims: While surgical left atrial appendage occlusion (SLAAO) reduces stroke in atrial fibrillation (AF) patients, its efficacy in patients without pre-operative AF but with CHA₂DS₂-VASc ≥2 remains uncertain despite their high post-operative AF risk (15-54%). The aim of this study was to evaluate whether prophylactic SLAAO reduces post-operative thrombo-embolic events in valvular surgery patients.

Methods: The OPINION was a multicentre, open-label, randomized, superiority trial conducted at three cardiac surgery centres in China. Eligible non-AF patients with CHA₂DS₂-VASc ≥2 and an indication for valve repair or replacement due to mitral or aortic valve lesions were randomly assigned (1:1) to undergo SLAAO (intervention arm) or not undergo SLAAO (control arm) during surgery. The primary outcome was a composite of ischaemic stroke, transient ischaemic attack (TIA), or cardiovascular mortality assessed at 1 year. The primary analysis was done in the intention-to-treat population.

Results: Between April 2021 and June 2024, a total of 2157 patients were enrolled and randomized. After exclusion of 39 patients who withdrew informed consent, 2118 participants were included in the intention-to-treat population (1062 in the SLAAO group and 1056 in the control group). Baseline characteristics were well-balanced between the SLAAO group and control group (mean age 55.5 [11.4] vs 55.6 [11.5] years, P = .65; female 32.9% vs 32.3%, P = .78; CHA2DS2-VASc score 2.88 [0.98] vs 2.87 [0.96], P = .83; median EuroSCORE II 1.58% [1.42%] vs 1.56% [1.28%], P = .74). The 1-year primary endpoint occurred in 73 (6.9%) patients in the SLAAO group and in 87 (8.2%) patients in the control group (hazard ratio 0.83; 95% confidence interval 0.61-1.14; P = .25).

Conclusions: For valvular surgery patients with CHA₂DS₂-VASc scores ≥2 but no pre-operative AF, routine prophylactic left atrial appendage closure did not significantly reduce the incidence of the primary composite endpoint (ischaemic stroke, TIA, and cardiovascular mortality) at 1-year follow-up.

Trial Registration: ChiCTR.org registry ChiCTR2100042238.