Incidental Coronary Artery Calcification and Stroke Risk in Patients With Atrial Fibrillation

OBJECTIVE. Atrial fibrillation (AF) is a major risk factor for stroke. The CHA₂DS_2-VASc score is used to risk stratify patients, and the score includes known coronary artery disease (CAD) as a variable. The aim of this study was to assess if the presence of incidental coronary artery calcification (CAC), without known CAD, is associated with stroke independent of CHA₂DS₂-VASc variables. MATERIALS AND METHODS. A retrospective review of health records was performed for patients who had AF, a chest CT scan performed within 1 year, and a subsequent visit for stroke. Patients with CAD and other vascular disease, a mechanical valve, or who were older than 74 years old were excluded. Included patients were one-to-one matched by age and CHA₂DS₂-VASc risk factors to patients who had had similar follow-up but who did not have a stroke. Nongated CT images were reviewed for CAC. Univariate and Cox regression analyses were performed. RESULTS. A total of 203 patients met the study criteria, and 203 matched patients without stroke were identified. Median age was 61 years old with stroke and 62 years old without stroke (p = 0.99). In both groups, 82 (39.0%) were women and the median CHA₂DS₂-VASc was 2 (interquartile range, 1-2). Anticoagulation medication was prescribed to 46 (22.7%) patients in the group who had had a stroke and 52 (25.6%) in the group without stroke (p = 0.49). On Cox regression analysis, CAC was associated with stroke (hazard ratio [HR], 1.47; 95% CI, 1.10-1.97; p < 0.01) and mortality (adjusted HR, 1.41; 95% CI, 1.02-1.95; p = 0.04). CONCLUSION. Patients with AF and incidental CAC depicted on chest CT have an increased risk of stroke and mortality beyond established risk factors.