Because macroangiopathy is a ma jor complication of diabetes, evalua tion of the carotid arteries for possible obstruction is of primary importance. Patients with transient ischemic at tacks, a precursor of strokes, are liable to have either a mechanical reduction of flow secondary to stenosis or a re lease of emboli from extracranial plaques. After a definitive diagnosis by angiogram, dissection of a tight lesion is indicated. Asymptomatic bruits should be evaluated by noninvasive techniques for possible prophylactic endarterectomy.