Cerebrovascular Occlusive Disease 
Strokes are caused by reduction in the circulation of blood to the brain and may result in paralysis, blindness, loss of speech, or even death. A number of factors contribute to stroke risk, including hypertension, diabetes, and atherosclerotic narrowing (stenosis) of the carotid arteries in the neck. Several large clinical trials recently have reconfirmed that the surgical treatment of serious carotid artery disease with an operation called carotid endarterectomy (CEA) provides significant protection from strokes, irrespective of whether carotid stenosis already has produced temporary neurological symptoms or is entirely symptom-free (asymptomatic).
Risk Factors
Although CEA consequently has become one of the most common surgical procedures performed in the United States, its complication rates – including the risk for a stroke caused by the operation itself – often are different from one hospital and from one surgeon to the next. Therefore, patients who have been advised to have CEA should request specific information regarding their chances for complications wherever the operation is to be done.
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High-grade stenotic lesions in the right (A) and left (B) intracranial vertebral arteries
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Angiograms showing the right (A) and left (B) carotid circulation and noncommunicating posterior communicating arteries
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After balloon dilation and stenting, both intracranial vertebral arteries (right, A and left, B) have near-normal luminal diameter
