Natural history and indications for surgery in carotid stenosis

Atherosclerotic stenoses of the internal carotid artery are often the underlying cause for ischemic stroke. Several studies show a strong correlation between the grade of stenosis and stroke risk. When cerebral symptoms occur in patients with a carotid artery stenosis of 60% or more the risk of stroke within the following 12 months is over 10%. Large randomised studies show that patients with a high grade carotid artery stenosis benefit clearly from carotid endarterectomy. Surgical treatment reduces stroke risk by more than 70% in these patients. Symptomatic patients with stenoses less than 40% do not benefit by endarterectomy even when surgical complication rate is low. The benefit of carotid endarterectomy is proven for asymptomatic stenoses, too. In asymptomatic patients, however, an operative procedure is justified only when surgical complication rate is 3% or less.