Background: Interventional left atrial appendage occlusion (LAAO) is a routinely performed alternative to oral anticoagulation for the prevention of thromboembolic events (TE) in patients with atrial fibrillation (AF) and contraindications to oral anticoagulation (OAC). The benefits of the LAAO in patients with a low CHA₂DS₂-VASc score are controversially discussed, and its effectiveness and safety have not been specifically evaluated in patients with high versus low CHA₂DS₂-VASc score so far.

Methods: LAARGE is prospective observational study depicting the clinical reality of LAAO in Germany (ClinicalTrials.gov Identifier: NCT02230748). LAAO was conducted with different standard devices, and the patients were followed up for one year. In the sense of an as-treated analysis, patients with started procedure and documented CHA₂DS₂-VASc score were selected from the whole database. Procedural details, periprocedural complications up to hospital discharge and adverse events during the follow-up period were centrally recorded and evaluated by an independent critical event committee based on the original medical records in case of severe events.

Results: 638 patients from 38 centers were divided into two groups: CHA₂DS₂-VASc score ≤2 points, i.e., low risk (10.2%), and >2 points, i.e., high risk (89.9%). The latter patients were older, had a pronounced cardiovascular risk profile, and had experienced previous strokes (0 vs. 24.0%; p<0.001). Implantation success was consistently high (97.6%), frequencies of intrahospital MACCE (0 vs. 0.5%) and other major complications (4.6 vs. 4.0%) were low (each p=NS). A relevant number of moderate complications were also observed in the low-risk group (12.3 vs. 9.4%; p=NS). Kaplan-Meier estimation showed a trend towards a higher combined rate of all-cause death and stroke in the high-risk group (4.9 vs. 13.0%; p=0.071; HR 0.36 (0.11-1.14)), which was no longer evident after adjustment for relevant confounding factors. Frequencies of non-fatal strokes (0 vs. 0.7%) and severe bleedings (0 vs. 0.7%) were consistently low across both groups (each p=NS). The vast majority of patients did not receive OAC upon hospital discharge (92.1%; p=NS).

Conclusions: A relevant number of moderate periprocedural complications occurred in patients with a low CHA₂DS₂-VASc score. Patients with such a low risk of TE should therefore not receive LAAO at this early stage and should preferably be evaluated annually for disease progress. Effectiveness in stroke prevention was high regardless of the CHA₂DS₂-VASc score and severe bleeding complications were rare throughout the follow-up period.