Following open-heart surgery, atrial fibrillation and stroke occur frequently. Left atrial appendage closure added to elective open-heart surgery could reduce the risk of ischemic stroke. We aim to examine if routine closure of the left atrial appendage in patients undergoing open-heart surgery provides long-term protection against cerebrovascular events independently of atrial fibrillation history, stroke risk, and oral anticoagulation use. Long-term follow-up of patients enrolled in the prospective, randomized, open-label, blinded evaluation trial entitled left atrial appendage closure by surgery (NCT02378116). Patients were stratified by oral anticoagulation status and randomized (1:1) to left atrial appendage closure in addition to elective open-heart surgery vs standard care. The primary composite endpoint was ischemic stroke events, transient ischemic attacks, and imaging findings of silent cerebral ischemic lesions. Two neurologists blinded for treatment assignment adjudicated cerebrovascular events. In total, 186 patients (82% males) were reviewed. At baseline, mean (standard deviation (SD)) age was 68 (9) years and 13.4% (n = 25/186) had been diagnosed with atrial fibrillation. Median [interquartile range (IQR)] CHA₂DS₂-VASc was 3 [2,4] and 25.9% (n = 48/186) were receiving oral anticoagulants. Mean follow-up was 6.2 (2.5) years. The left atrial appendage closure group experienced fewer cerebrovascular events; intention-to-treat 11 vs 19 (P = 0.033, n = 186) and per-protocol 9 vs 17 (P = 0.186, n = 141). Left atrial appendage closure as an add-on open-heart surgery, regardless of pre-surgery atrial fibrillation and oral anticoagulation status, seems safe and may reduce cerebrovascular events in long-term follow-up. More extensive randomized clinical trials investigating left atrial appendage closure in patients without atrial fibrillation and high stroke risk are warranted.