Characteristics of Recurrent Ischemic Stroke in Egyptian Patients with Atrial Fibrillation Receiving Direct Oral Anticoagulants: A Retrospective Study.

Introduction: Atrial fibrillation (AF) is a major cause of ischemic stroke (IS). Direct oral anticoagulants (DOACs) are the standard of care, yet recurrent IS may occur despite therapy. This study aimed to characterize patients with recurrent IS while on DOACs and to explore competing non-cardioembolic mechanisms. Methods: A single-center retrospective study of patients with AF who developed recurrent ischemic stroke while on DOACs was conducted between January 2020 and December 2023. We assessed the presence of vascular risk factors, type of index event(s), type of DOACs, pre-stroke CHA2DS2-VASc and Stroke Prognosis Instrument II (SPI-II) scores, stroke severity, and radiological data (brain imaging, carotid vertebrobasilar duplex, and transthoracic echocardiography) to detect the possible underlying stroke mechanism(s).Results: Twenty-eight patients (mean age 68.14 ± 10 years; 60.7% female) were included. Most presented with moderate or moderate-to-severe stroke (median NIHSS 8.5). Stroke mechanisms were cardioaortic embolism in 57%, small-artery occlusion in 21%, large-artery atherosclerosis in 7%, and undetermined in 14%. Nearly all patients had elevated CHA2DS2-VASc and SPI-II scores, reflecting a high recurrence risk. Conclusions: Recurrent IS in AF patients on DOACs were frequently linked to non-cardioembolic mechanisms in our cohort. Comprehensive evaluation is essential to optimize secondary prevention strategies.