CAROTID ARTERY INTERVENTION
The era of percutaneous or endovascular revascularization techniques was ushered in by Dotter in 1964, and then advanced by Gruentzig with the invention of the balloon angioplasty catheter. The technique of percutaneous transluminal angioplasty (PTA) has been used in both peripheral and coronary vessels to great success and, in many circumstances, has largely replaced surgical therapy as the treatment choice. The use of PTA in the extracranial carotid circulation began in Europe. In a worldwide survey of carotid intervention published in 1998, the specialty of cardiology was dominant, responsible for more than 60% of all the reported cases. Cardiologists have continued to lead this field with the development of embolic protection devices (EPDs); initially proven in saphenous vein graft intervention, cardiologists are already comfortable using this technology.
The majority of cerebral ischemic events are a focal manifestation of a systemic disease, atherosclerosis. Extracranial atherosclerotic carotid artery disease accounts for slightly more than half of the 731,000 strokes per year in the United States. Stroke is the third leading cause of death after coronary artery disease and cancer in the United States, and it is the leading cause of disability. In the Framingham study, 70% of all stroke patients had hypertension, 70% had coronary artery disease, and 30% had peripheral vascular disease.
There are 2 main types of stroke: ischemic and hemorrhagic. Ischemic stroke results from a reduction of blood flow due to emboli, thrombosis, or hypoperfusion. Hemorrhagic stroke includes primary cerebral hemorrhages or hemorrhage secondary to an ischemic event. Atherosclerotic carotid artery stenoses most often cause symptoms due to emboli events. A minority of ischemic strokes are caused by thrombotic occlusion, which is in contrast to acute coronary syndromes, which are usually due to thrombotic vessel occlusion.
Anatomically, the 2 internal carotid arteries and 2 vertebral arteries come together at the base of the skull to form the circle of Willis (Fig. 57-1), which is an ideal anastomotic network. In theory, a single vessel could supply the circulatory needs of the entire brain. However, although a circle of Willis is present in every brain, there is a huge amount of individual variability, and fewer than half are complete anastomotic networks.
Circle of Willis. Two internal carotid arteries and 2 vertebral arteries come together at the base of the skull to form the circle of Willis.
Stroke Prevalence, Demographics, and Etiology
The third leading cause of death in the United States is stroke, with more than three-quarters of a million strokes per year. Stroke is a leading cause of functional impairment in adults with approximately 20% of survivors requiring institutional care and up to one-third having a permanent disability. More worrisome, however, is the fact that as the population ages, ...