Identification of Markers Associated With Development of Stroke in “Clinically Low‐Risk” Atrial Fibrillation Patients

BACKGROUND: Stroke and thromboembolic events may still occur in “clinically low‐risk” atrial fibrillation (AF) patients as categorized by CHA (2) DS (2)‐VASc score. Our aim was to assess the proportion of “clinically low‐risk” patients using a nongender CHA (2) DS (2)‐VASc (ie, CHA (2) DS (2)‐VA) score of 0 to 1 among patients who experienced AF‐associated stroke and to identify markers associated with stroke in “clinically low‐risk” patients. METHODS AND RESULTS: We retrospectively recruited nonvalvular AF patients who experienced embolic stroke between 2013 and 2016 from 9 institutes in Korea. AF patients with CHA (2) DS (2)‐VA score of 0 to 1 at the time of stroke were analyzed and compared with “clinically low‐risk” AF patients without stroke. A total of 3033 subjects with AF‐associated stroke were recruited. Of these, 583 patients (19.2%) had CHA (2) DS (2)‐VA score of 0 to 1. On multivariate analysis, age (≥60 years), N‐terminal pro B‐type natriuretic peptide (≥300 pg/mL), creatinine clearance (<50 mL/min), and left atrial dimension (≥45 mm) were independently associated with stroke. With the combined application of these 4 factors (collectively, ABCD score) to the “clinically low‐risk” patients, the c‐index was 0.858 (95% CI 0.838–0.877; P<0.001). CONCLUSIONS: The present study suggests a new insight into how additional use of markers can further refine stroke risk differentiation among AF patients initially classified as “clinically low‐risk.” CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT03147911.