- Have a presumed stroke etiology: Lacunar or small vessel thrombosis, extra-cranial or intracranial atherosclerotic stenosis or dissection, arteriopathy or vasculitis, hypercoagulable state, aortic arch plaque with or without mobile elements, or evidence of a low-risk cardiac source (e.g., patent foramen ovale with or without atrial septal aneurysm and with or without evidence of venous thromboembolic source).