What to do in the Emergency Department (ED) if a carotid artery bruit is heard?

Management of Carotid Artery Bruit in the Emergency Department

When a carotid artery bruit is detected in the Emergency Department, the most appropriate initial diagnostic test is duplex carotid Doppler ultrasonography performed by a qualified technologist in a certified laboratory to detect hemodynamically significant carotid stenosis. 1

Initial Assessment

• Duplex carotid Doppler is a very accurate and useful screening test for evaluating carotid stenosis in asymptomatic patients with a carotid bruit, with 90% sensitivity and 94% specificity for identifying clinically significant stenosis (>70%) 1
• The presence of a carotid bruit correlates more closely with systemic atherosclerosis than with significant carotid stenosis, but still warrants investigation 1
• Patients with carotid bruits have approximately 2.5 times higher risk of stroke compared to those without bruits 2

Diagnostic Algorithm

1. Initial imaging: Carotid Duplex Ultrasonography

   • Advantages: No IV contrast needed, non-invasive, widely available 1
   • Stratifies stenosis into mild (<50%), moderate (50-69%), and severe (>70%) 1
   • In uncomplicated cases, ultrasound alone may be sufficient 1

2. Interpretation of Ultrasound Results:

   • If stenosis <50%: Medical management and risk factor modification 1
   • If stenosis 50-69%: Consider additional imaging based on patient-specific factors 1
   • If stenosis >70%: Consider additional imaging for potential surgical intervention 1

3. Additional imaging (if indicated):

   • MRA or CTA of the neck may be considered if carotid stenosis >70% and revascularization is contemplated 1
   • Catheter-directed cerebral angiography has the highest spatial and temporal resolution but is more invasive 1

Important Clinical Considerations

• Caution must be exercised when evaluating patients with extremely severe stenosis or multivessel involvement, as Doppler can overestimate stenosis with contralateral disease or underestimate critical high-grade stenosis 1
• MRI of the head is not recommended in the initial workup for asymptomatic patients with carotid bruit but may be useful later to evaluate for sequelae such as clinically silent strokes 1
• Transcranial Doppler is not supported by literature for initial workup of asymptomatic patients with carotid bruit 1

Management Based on Findings

• Asymptomatic patients with hemodynamically significant stenosis (>70%) might warrant surgical intervention 1
• The risk of stroke in patients with hemodynamically significant bruits (24%) is significantly higher compared to those with non-hemodynamically significant bruits (4.8%) 3
• Patients with carotid bruits should be evaluated for other manifestations of atherosclerotic disease, as they are at increased risk of cardiac events 1

Common Pitfalls to Avoid

• Do not assume all carotid bruits indicate significant stenosis - approximately 32% of patients with bruits have normal carotid arteries 4
• Do not rely solely on the presence or absence of a bruit for clinical decision-making, as the false negative rate for severe disease can be as high as 43% 4
• Avoid routine screening with carotid duplex ultrasonography in asymptomatic patients who have no clinical manifestations of or risk factors for atherosclerosis 1
• Do not order MRI or CT perfusion studies as initial tests in the evaluation of asymptomatic carotid bruits 1