This prospective randomized controlled , open-labeled trial , with blinded end point evaluation ( PROBE design ) tested superiority of aspirin 75 to 150 mg/d plus clopidogrel 75 mg/d ( A+C ) over warfarin therapy ( international normalized ratio 2-3 ) in patients with ischemic stroke , transient ischemic attack , or peripheral embolism with plaque in the thoracic aorta > 4 mm and no other identified embolic source .