ABSTRACT NUMBER: ESOC2026A1208 PROSPECTIVE STUDY OF EMBOLIC STROKE OF UNDETERMINED SOURCE (ESUS): CLINICAL, RADIOLOGICAL, AND ETIOLOGICAL CHARACTERISTICS

Abstract Background and aims Embolic Stroke of Undetermined Source (ESUS) is a non-lacunar ischemic stroke with no identifiable cause, representing about 17% of ischemic strokes. This study aimed to describe the demographic, clinical, radiological, and etiological features of ESUS patients. Methods We conducted a 3-year prospective study of 330 ischemic stroke patients at the Neurology Department of Monastir, of whom 66 (20%) met ESUS criteria. Results Among ESUS patients, 68.2% were men, with a mean age of 57 years. At least one cardiovascular risk factor was present in 30%, mainly hypertension (53%), smoking (48.5%), and diabetes (38.5%). A previous cerebrovascular event was reported in 18%. The mean NIHSS score at admission was 6.82. Neuroimaging showed predominant involvement of the carotid territory (72.7%), followed by the vertebrobasilar circulation (21.2%), with both territories involved in 6.1%. During etiological workup and follow-up, de novo atrial fibrillation was detected in 18.2% of patients; none was identified on admission ECG. Repeat 24-hour Holter monitoring detected AF in 13.7%, and 4.5% were diagnosed on ECG during follow-up. Valvular heart disease was present in 33.3%. A patent foramen ovale was found in 24.2%, with 62.5% considered high embolic risk. Non-stenotic atherosclerotic plaques were frequent, and aortic arch atheroma was identified in 27.3%, including 40% complex plaques (>4 mm). No malignancy was identified. Conclusions ESUS constitute a significant proportion of ischemic strokes. The frequent detection of de novo atrial fibrillation, valvular disease, and atheromatous plaques during follow-up underscores the need for comprehensive cardiovascular assessment and prolonged rhythm monitoring to optimize management and prognosis. Conflict of interest Yosr Boubaker. nothing to disclose