Internal carotid stenosis symptomatic patients who have a transient ischemic attack, amaurosis fugax, or minor nondisabling stroke in the distribution of the study artery within 180 days of inclusion and have been shown carotid artery stenosis ≥50% by angiography, ≥70% by ultrasound, or ≥70% by CT angiography or magnetic resonance (MR) angiography if ultrasound is 50% to 69%. Asymptomatic patients who have carotid artery stenosis of ≥60% by angiography, ≥70% by ultrasound, or ≥80% by CT angiography or MR angiography if ultrasound is 50% to 69%.