Atherosclerotic carotid stenosis may be asymptomatic or it may cause symptoms by embolism to either cerebral vessels in the brain or to the retinal arteries. Emboli to the cerebral arteries cause transient ischaemic attack (TIA) or cerebrovascular accident (CVA). Emboli to the retina produce amaurosis fugax or retinal infarction. It is important to note that there are other causes of TIAs, CVAs and retinal ischaemia apart from carotid stenosis.
Typically duplex ultrasound scan is the only investigation required for decision making (including proceeding to intervention) in carotid stenosis. Occasionally further imaging is required. One of several different imaging modalities, such as angiogram, computed tomography angiogram (CTA) or magnetic resonance imaging angiogram (MRA) may be useful. Each imaging modality has its advantages and disadvantages - the investigation chosen will depend on the clinical question and the imaging expertise, experience and equipment available.
The goal of treatment is to reduce the risk of stroke (cerebrovascular accident). Intervention (carotid endarterectomy or carotid stenting) can cause stroke, however where the risk of stroke from medical management alone is high, intervention may be beneficial. In selected, high-risk trial participants with asymptomatic severe carotid artery stenosis, carotid endarterectomy by selected surgeons reduces the 5-year absolute incidence of all strokes or perioperative death by approximately 5%. In excellent centers, carotid endarterectomy is associated with a 30-day stroke or mortality rate of about 3%; some areas have higher rates.
Clinically, risk of stroke from carotid stenois is evaluated by the presence or absence of symptoms and the degree of stenosis on imaging.