Early Anticoagulation in Acute Ischemic Stroke With Atrial Fibrillation.

Patients with atrial fibrillation who experience acute ischemic stroke (AIS) are at high risk of early recurrent ischemic stroke or systemic embolism. Timely initiation of anticoagulation is essential to prevent subsequent ischemic events but must be carefully balanced against the risk of hemorrhagic transformation or intracranial hemorrhage. Historically, early anticoagulation therapy with heparin or vitamin K antagonists for AIS has shown uncertain benefits. The safety and efficacy of early initiation of non-vitamin K oral anticoagulants, initially suggested by observational studies, have been confirmed by randomized controlled trials and further supported by an individual patient data meta-analysis. However, uncertainties remain in specific populations, including those with severe stroke, hemorrhagic transformation, and Asian patients, who are at an increased risk of intracranial bleeding and are underrepresented in clinical trials.