Study on Anti-Thrombotic Regimens for Secondary Prevention in Ischemic Stroke Patients With Possible Benefit From Anticoagulation Therapy

Inclusion Criteria: * Age ≥18 years * Ischemic stroke patients with undetermined etiology, within 14 days of onset, with completed etiological assessment * At least one of the following: 1. Cortical or multi-territorial infarct 2. Recurrent stroke or stroke on antiplatelet therapy 3. Left atrial diameter \>40 mm 4. Left ventricular dysfunction (EF 30-40% or regional wall motion abnormality) 5. Atrial premature beats \>1500/24h Exclusion Criteria: * Stenosis ≥50% in the responsible vessel or high-risk plaque * Identified cardioembolic source * PFO with planned closure * Malignancy * Indication for mandatory anticoagulation/antiplatelet therapy * Active bleeding (intracranial, subarachnoid, gastrointestinal, etc.) * History of intracranial hemorrhage * Current or recent gastrointestinal ulcer * Recent brain or spinal injury/surgery * Known or suspected vascular malformations or aneurysms * Severe renal impairment (CrCl \<30 ml/min) * Liver disease with bleeding risk (Child-Pugh B or C) * Pregnancy or lactation * Other contraindications to anticoagulation