Symptomatic and asymptomatic cerebrovascular disease.
Exclusion criteria included patients unable or unwilling to undergo one of the alternative treatment strategies, or who were unable to give informed consent, or if they had a disabling stroke with no useful recovery of function within the region supplied by the treatable artery. Patients were not eligible for the study if angiography showed thrombus in the affected artery, severe intracranial stenosis beyond the skull base, or a stenosis unsuitable for endovascular treatment e.g. because of tortuous vascular anatomy. However, patients did not need to have catheter angiography if a reliable non-invasive investigation had confirmed stenosis. Patients were not excluded if contraindications were noted after random assignment. There was no age limit.