• Symptoms more often result from emboli than hypoperfusion
• 80% of patients with occlusive cerebrovascular disease have accessible arterial lesion in neck/chest
• When blood supply decreases below critical level, cellular death occurs in minutes
• Embolization most common mechanism of stroke from carotid lesions
• Most strokes due to lesions of internal carotid but can be from innominate/ aorta
• Low wall shear stress, flow separation, loss of unidirectional flow may lead to atherosclerosis in carotid bulb
• Neurologic dysfunction without infarction can be produced in 2 ways:
• Antiplatelet therapy decreases stroke rates by 5%
• 33% of patients who have had transient ischemic attacks (TIAs) eventually suffer stroke
• 20% of patients with amaurosis fugax will suffer stroke
• Stroke risk after TIA correlates with severity of internal carotid stenosis
• Mortality from initial stroke is 20-30%
• Subclavian stenosis more common in left artery than in right
• Carotid duplex US useful to demonstrate plaque morphology and degree of stenosis rapidly and accurately
• Carotid duplex US velocity criteria indicates degree of luminal narrowing—increases with increased stenosis
• Duplex US is initial test
• Arteriogram should be only done selectively
• NASCET trial: Reported in 2 major parts
-Symptomatic patients with 70-99% stenosis randomized to receive aspirin alone or aspirin plus carotid endarterectomy
-2-year stroke rate was 26% for aspirin alone vs 9% for aspirin plus carotid endarterectomy
-In patients ...
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