Carotid artery stenosis (CAS) is an atherosclerotic, degenerative disease of the common carotid artery and internal carotid artery. Risk factors include advanced age, tobacco use, arterial hypertension, and diabetes mellitus. Depending on the extent of stenosis, ischemia in the carotid perfusion territory can result in amaurosis fugax, transient ischemic attack (TIA), or stroke. Carotid duplex ultrasonography is the initial test of choice for evaluating the carotid artery and measuring the degree of stenosis. Management depends on the degree of stenosis and patient factors (e.g., life-expectancy, comorbidities). Lifestyle modifications, antiplatelet and statin therapy, and risk factor modifications (e.g., with antihypertensive therapy) are recommended for all patients and should be continued indefinitely. is recommended for and may be considered for if the periprocedural risks are acceptable. Screening for asymptomatic carotid stenosis is controversial.
- Symptomatic carotid stenosis: symptoms attributable to carotid stenosis within the past 6 months
- Asymptomatic carotid stenosis: no recent (< 6 months) symptoms attributable to carotid artery stenosis
- Many patients are asymptomatic.
- Symptomatic patients may present with
- Examination findings
General principles 
- Evaluate for and manage acute neurological symptoms.
- Perform carotid artery imaging in all patients with .
- is controversial and is detailed in the “Prevention” section below.
CDUS permits direct visualization of the vessel wall and flow measurement at the site of the stenosis by .
- Indications: first-line imaging modality for suspected 
- Findings 
Magnetic resonance angiography (MRA) or CT angiography (CTA)
- Indications 
- Luminal narrowing at the site of the stenosis
- Carotid plaques and calcification
- Additional considerations
- Indications 
- Findings: Similar to CTA or MRA
- Important consideration: DSA is an invasive procedure with a higher risk of mortality and stroke than imaging modalities with comparable diagnostic accuracy (e.g., CTA).
General principles 
- All patients: Initiate .
- Revascularization is typically indicated.:
- revascularization for patients with .: Consider 
- Bilateral carotid stenosis is uncommon; management is similar to that of unilateral carotid stenosis. 
- Consult specialists as needed.
Medical management 
Carotid stenosis is a type of atherosclerosis should be initiated in all patients and continued indefinitely (i.e., even after ).and measures to prevent further progression of
- Lifestyle modifications: e.g., smoking cessation, heart-healthy diet
Long-term ; single-agent antiplatelet therapy
- Asymptomatic carotid stenosis: aspirin 
Symptomatic carotid stenosis
- Medical management alone or after carotid endarterectomy: single-agent antiplatelet therapy (e.g., aspirin OR clopidogrel ) 
- After carotid artery stenting: short course of dual antiplatelet therapy (e.g., clopidogrel PLUS aspirin for 1 month), followed by long-term single-agent antiplatelet therapy with aspirin 
- Long-term 
- Manage modifiable risk factors for atherosclerosis (e.g., diabetes mellitus, hypertension).
- See “ ” and “ ” for further detail.
- Timing: ideally performed within 14 days of symptom onset
- Periprocedural optimization: e.g., beta blockers to control blood pressure, initiate statin therapy, withhold clopidogrel as needed 
Indications : Periprocedural risk and patient life-expectancy, comorbidities, and preferences must also be considered. 
- Asymptomatic patients with : Consider revascularization if the operator's risk of procedural morbidity and mortality risk is low (< 3%). 
- Carotid stenosis < 50%
- Chronic complete carotid occlusion
- Severely disabling stroke
Carotid endarterectomy (CEA) is usually considered the first-line treatment for carotid stenosis. If the patient is not a good candidate for surgery or the lesion characteristics preclude surgical treatment, carotid artery stenting may be preferred.
Carotid endarterectomy: a surgical procedure in which the inner lining of a carotid artery is removed, along with any associated atherosclerotic deposits
- Advantages: lower periprocedural stroke rate than carotid artery stenting, especially in patients > 70 years of age 
- Carotid artery stenting: angioplasty and stenting of the carotid artery (via a transfemoral or transcarotid approach)
- Carotid artery bypass grafting: Uncommonly required; may be considered for recurrent or bilateral severe carotid stenosis. 
Recommendations for the screening for asymptomatic carotid stenosis vary. As of 2021, the US Preventive Services Task Force (USPSTF) recommends against screening for asymptomatic individuals, including those with cardiovascular risk factors and carotid bruits. However, other guidelines suggest screening for carotid stenosis in asymptomatic individuals with a carotid bruit and/or risk factors for cardiovascular disease who are potential candidates for carotid intervention.
- Indications: Consider screening for asymptomatic carotid stenosis in individuals with any of the following 
- Screening modalities: noninvasive imaging is preferred (e.g., CDUS, CTA, MRA) 
- Management: See “Treatment” section for details if significant (≥ 50%) asymptomatic carotid stenosis is detected on screening.