When is checking for carotid stenosis recommended?

When to Check for Carotid Stenosis

Routine screening for asymptomatic carotid artery stenosis is not recommended in the general adult population as the harms outweigh the benefits. 1, 2

Appropriate Indications for Carotid Stenosis Evaluation

Symptomatic Patients

• Patients with transient retinal or hemispheric neurological symptoms of possible ischemic origin should undergo non-invasive imaging for carotid stenosis 1
• Patients who develop focal neurological symptoms corresponding to the territory supplied by the left or right internal carotid artery should be evaluated with duplex ultrasonography 1
• Individuals with a carotid-area transient ischemic attack should be evaluated promptly for consideration of carotid endarterectomy 1
• Patients presenting with stroke, TIA, or ipsilateral blindness (amaurosis fugax) should be assessed for carotid stenosis 3

High-Risk Asymptomatic Patients

• Duplex ultrasonography might be considered in asymptomatic patients with two or more of the following risk factors: hypertension, hyperlipidemia, tobacco smoking, family history of atherosclerosis before age 60 in a first-degree relative, or family history of ischemic stroke 1
• Screening might be considered for asymptomatic patients with known atherosclerotic disease in other vascular beds (symptomatic peripheral arterial disease, coronary artery disease, or atherosclerotic aortic aneurysm) 3
• Patients with multiple atherosclerotic risk factors may be considered for screening, though it remains unclear whether establishing a diagnosis would justify actions that affect clinical outcomes 1

When Screening is Not Recommended

• Routine screening in the general adult population without symptoms or risk factors for atherosclerosis 1
• Patients with neurological or psychiatric disorders unrelated to focal cerebral ischemia (brain tumors, degenerative disorders, infectious conditions, psychiatric disorders, or epilepsy) 1
• Routine serial imaging for patients who have no risk factors for atherosclerotic carotid disease and no disease evident on initial testing 1

Risk Factors for Carotid Artery Stenosis

• Older age (especially >65 years) 1, 4
• Male sex 1
• Hypertension 1, 4
• Smoking 1
• Hypercholesterolemia/dyslipidemia 1, 5
• Diabetes 5
• Heart disease 1

Important Considerations and Caveats

• The prevalence of significant carotid stenosis (>60-99%) in the general population over age 65 is only about 1%, making widespread screening inefficient 1, 4
• Even in elderly hypertensive populations, the prevalence of high-grade stenosis is low, casting doubt on the cost-effectiveness of generalized screening 4
• Screening tests (particularly duplex ultrasonography) have imperfect sensitivity and specificity, leading to many false-positive results that may result in unnecessary invasive procedures 1
• Confirmatory tests like digital subtraction angiography can themselves cause strokes 1
• Carotid endarterectomy carries a 30-day stroke or mortality rate of about 3% even in excellent centers, with higher rates in some areas 1
• The Society for Vascular Surgery and American Society of Neuroimaging have more liberal screening recommendations than the USPSTF, suggesting screening for adults over 55-65 years with multiple cardiovascular risk factors 1

Recommended Approach

1. Evaluate for carotid stenosis in patients with neurological symptoms in the carotid territory
2. Consider evaluation in asymptomatic patients with multiple risk factors or known atherosclerotic disease in other vascular beds
3. Avoid routine screening in the general asymptomatic population
4. When screening is indicated, use duplex ultrasonography as the initial test
5. For equivocal results, consider MRA or CTA as confirmatory tests 1

Remember that managing modifiable risk factors (hypertension, hyperlipidemia, smoking) is more beneficial for stroke prevention in the general population than screening for asymptomatic carotid stenosis 1.