Patients who have blocked carotid arteries, the major source of blood flow to the brain, even if there are no symptoms, experience significant improvements in intellectual functioning after they undergo surgery to correct this problem, investigators reported Friday at the Society of Interventional Radiology's annual meeting in Toronto. In fact, younger patients and those who have not had a stroke appear to experience the most benefit from the procedure. Carotid stenting involves placement a "stent," a device use to prop open the blocked vessels. Strokes can occur when plaques that have formed in the carotid arteries, which lie on each...