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Pathophysiology of symptoms from carotid atherosclerosis

Karen L Furie, MD, MPH
Section Editor
Jose Biller, MD, FACP, FAAN, FAHA
Deputy Editor
John F Dashe, MD, PhD


The symptoms and pathologic substrate of carotid artery atherosclerotic occlusive disease were first described by C Miller Fisher in 1951 [1]. He related atherosclerotic disease at the carotid bifurcation to ischemic symptoms in the ipsilateral eye and brain. The modern era has seen an extraordinary expansion in our approach to the diagnosis and management of patients with carotid artery stenosis.

Stroke, due to atherothrombosis of the extracranial carotid arteries, is caused by a combination of factors involving the blood vessels, the clotting system, and hemodynamics. This interaction explains the mechanism of ischemic stroke in patients with carotid atheroma which may be due to artery-to-artery embolism or low cerebral blood flow.

The classification of symptomatic status of the internal carotid artery, the mechanism of symptom production, and the associated physical signs are reviewed here. Other issues, such as the methods for evaluating carotid stenosis and therapies available for the treatment of carotid artery disease, are discussed separately. (See "Evaluation of carotid artery stenosis" and "Overview of secondary prevention of ischemic stroke" and "Management of symptomatic carotid atherosclerotic disease" and "Management of asymptomatic carotid atherosclerotic disease".)


Carotid atherosclerosis is usually most severe within 2 cm of the bifurcation of the common carotid artery, and predominantly involves the posterior wall of the vessel. The plaque encroaches on the lumen of the internal carotid artery and often extends caudally into the common carotid artery. An hourglass configuration to the stenosis typically develops with time.

Regardless of their location, carotid plaques were associated with an increased risk of stroke in an observational study of older adult men and women [2] and an increased risk of mortality in an observational study of older adult men [3]. In addition to a reduction in vessel diameter induced by the enlarging plaque, thrombus can become superimposed on the atheroma which will further increase the degree of stenosis. Thus, the mechanism of stroke may be embolism of the thrombotic material or low flow due to the stenosis with inadequate collateral compensation [1,4-8].

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Literature review current through: Nov 2017. | This topic last updated: Jan 31, 2017.
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