Coronary atherosclerotic burden in patients with embolic stroke of undetermined source

Introduction Embolic Stroke of Undetermined Source (ESUS) is a subtype of cryptogenic stroke with no clear etiology despite thorough evaluation. Atrial fibrillation (AF) is detected in only ~40% of cases, and trials of empiric anticoagulation have failed to reduce recurrence, suggesting other mechanisms such as subclinical atherosclerosis may contribute. Coronary artery calcium (CAC) scoring is a validated marker of atherosclerosis, yet its burden in ESUS remains underexplored. Patients and methods We conducted a retrospective cohort study of consecutive ESUS patients admitted between April 2019 and December 2023 who underwent cardiac CT angiography (CCTA) during diagnostic work-up. CAC scores were calculated using the Agatston method, and percentiles were derived from the MESA database, adjusted for age, sex, and ethnicity. Patients with prior coronary interventions were excluded. Results Among 165 ESUS patients (median age 73.0 [IQR 66.5–82.0]; 47.9% female), the median CAC score was 225 [IQR 41.5–623.5] AU, and the median CAC percentile was 65 [IQR 40.05–85.0], significantly higher than population norms (p < 0.001). Patients ⩽65 years had higher CAC percentiles than older patients (80.0 [58.2–90.7] vs 61.0 [36.0–80.0], p = 0.002), despite similar CAC scores (p = 0.396). Conclusion ESUS patients exhibit a high burden of coronary atherosclerosis, particularly notable in younger individuals. Elevated CAC may reflect both subclinical atherosclerosis and a broader cardiovascular risk profile, offering insight into stroke pathophysiology and the limited efficacy of empiric anticoagulation. CAC assessment could improve etiologic classification and inform tailored secondary prevention.