WITH THE publication of the Asymptomatic Carotid Atherosclerosis Study (ACAS) results in 1995,¹much controversy again arose over whether to offer carotid endarterectomy (CE) to asymptomatic patients with severe carotid stenosis.^2-4In 1985, when laying the ground work for this trial, the investigators had hoped to end much of the controversy and settle what was then felt to be a simple but important question: Is CE helpful or harmful to asymptomatic patients harboring carotid lesions of hemodynamic significance? To my thinking, 3 basic conclusions came from that work: First, that skilled surgeons could perform CE with a 5-year morbidity and mortality rate that was less than half of that obtained with the best medical management alone. Second, the absolute risk of stroke and death with medical management was only 2.3% per year, which was less than half that predicted from historical data available at the time. Finally, conventional cerebral arteriography was dangerous in these high-risk patients, resulting in a complication rate that nearly doubled the 1.5% morbidity and mortality rate of the surgical procedure alone.