Abstract Number: Esoc2026a2330 Clinical Phenotype of Patients With Atrial Fibrillation Presenting With Ischemic Stroke Despite Anticoagulation

Abstract Background and aims Oral anticoagulation substantially reduces the risk of ischemic stroke (IS) in patients with atrial fibrillation (AF). Despite optimal anticoagulation, a clinically relevant subset of patients’ experiences IS. The clinical phenotype of these patients remains insufficiently studied. The study analyses the demographic and clinical characteristics of anticoagulated patients with AF presenting with acute IS and identifies factors associated with stroke severity and early functional outcome. Methods A prospective, single-center cohort study was conducted on consecutive patients with acute IS and anticoagulated AF (DOACs or vitamin K antagonists) prior to stroke onset. Demographic data, comorbidities, anticoagulant regimen, and CHA₂DS₂-VASc were recorded. Stroke severity was assessed by the NIHSS and early functional outcome was evaluated using the mRS at discharge. Results 55 patients were included (median age 79 years;40% male), 89% of whom receiving DOAC therapy. All of them had a high baseline thromboembolic risk with a median CHA₂DS₂-VASc score of 5 and a high prevalence of cardiovascular comorbidities. Stroke severity on admission was moderate, with a median NIHSS score of 7 (IQR 5–13). Early unfavorable functional outcome (mRS≥3) occurred in 52.7% of patients. In this high-risk population, stroke severity and early functional outcome appeared to be more closely related to advanced age and comorbidity burden than to the anticoagulant regimen used. Conclusions Patients with AF who experience IS despite optimal anticoagulation represent a high-risk clinical phenotype characterized by advanced age and comorbidity burden, underscoring the multifactorial nature of residual stroke risk beyond anticoagulant therapy alone. Conflict of interest Veronika Vasileva: nothing to disclose. Maya Danovska: nothing to disclose. Yoanna Todorova: nothing to disclose. Diana Marinova-Trifonova: nothing to disclose. Plamen Stoev: nothing to disclose. Figure 1 - belongs to Methods Figure 2 - belongs to Results