Advances in research and clinical decision strategies for anticoagulation timing in acute ischemic stroke patients with atrial fibrillation

Atrial fibrillation (AF) is a major risk factor for acute ischemic stroke (AIS), and oral anticoagulation is the cornerstone of secondary prevention. The optimal timing of anticoagulation initiation remains controversial because of the need to balance the risks of early ischemic recurrence and hemorrhagic transformation. Recent randomized controlled trials and meta-analyses indicate that early initiation of direct oral anticoagulants (DOACs) is generally safe in appropriately selected patients and may reduce recurrent ischemic events without increasing the risk of symptomatic intracranial hemorrhage. However, evidence remains limited in patients with severe stroke, hemorrhagic transformation, large infarcts, or recent reperfusion therapy, in whom the timing of anticoagulation should be individualized according to clinical and neuroimaging characteristics. The 2026 AHA/ASA guideline considers early oral anticoagulation reasonable in carefully selected patients with AIS and AF, particularly those with milder stroke severity, without specifying a uniform initiation window. Clinical decision-making should integrate stroke severity, neuroimaging findings, and individual thromboembolic and bleeding risks. Overall, current evidence supports a shift from fixed delay rules toward individualized anticoagulation strategies.