TIAs vs Prior Ischemic Stroke in AF Patients

"Patients with atrial fibrillation (AF) and prior transient ischemic attack (TIA) have a lower (albeit 'still high') risk of subsequent stroke during aspirin therapy than do patients with prior ischemic stroke. The use of warfarin therapy instead of aspirin for secondary prevention in AF patients with either prior TIA or stroke substantially reduces the absolute risk of ischemic stroke."