Patients with acute ischemic stroke who have undergone endovascular thrombectomy will be eligible to be included, and thrombus will be collected after obtaining informed consent. Enrolled patients will receive a comprehensive diagnostic evaluation and the best medical treatment according to recent stroke management guidelines. The mechanism of the stroke will be classified into atherosclerotic, cardiac embolism, others and unknown causes based on diagnostic workup. Patients will be monitored in an outpatient clinic for vascular events including stroke recurrence, death, and bleeding events, which will continue for up to two years after the initial stroke event. Thrombus information related to RNA expression patterns and histological characteristics will be analyzed to classify the stroke mechanism and predict future vascular events after the initial stroke.