Carotid artery stenosis
| Carotid artery stenosis | |
|---|---|
| Specialty | Cardiology  |
Carotid stenosis is a narrowing of the lumen of the carotid artery, usually caused by atherosclerosis. The unqualified term "carotid stenosis" in common medical usage refers to the stenosis in the proximal part of the internal carotid artery (at the carotid bulb), as this is the by far the most common site of stenosis within the carotid arteries. Stenosis in other parts of the carotid arteries does occur.
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.
Carotid artery stenosis can also present with the symptom of pulsatile tinnitus. Pulsatile tinnitus is due to turbulent blood flow created by the stenosis and produces a rhythmic sound often described as "whooshing" or "thumping". It's feature is the fact it is in beat with the carotid pulse. Turbulent blood flow also results in carotid artery bruits. Carotid artery bruits are a sign of carotid artery stenosis that are heard with or without a stethoscope on auscultation.
Diagnosis
Carotid stenosis is usually diagnosed by colour flow duplex ultrasound scan of the carotid arteries in the neck. This involves no radiation, no needles and no contrast agents that may cause allergic reactions. This test has moderate sensitivity and specificity, and yields many false-positive results.
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.
Screening
The U.S. Preventive Services Task Force (USPSTF) recommends against screening for asymptomatic carotid artery stenosis in the general adult population.[1]
Treatment
Options for treatment include:
- Medical management alone (an antiplatelet drug (or drugs) and control of risk factors for atherosclerosis)
- Medical management plus Carotid endarterectomy (surgical removal of the atheroma)
- Medical management plus Carotid stenting
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.[1]
Clinically, risk of stroke from carotid stenois is evaluated by the presence or absence of symptoms and the degree of stenosis on imaging.
References
- ^ a b Screening for Carotid Artery Stenosis. December 2007. U.S. Preventive Services Task Force. Agency for Healthcare Research and Quality, Rockville, MD.
See also
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