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Make the Diagnosis: Carotid Bruit

It is hard for physicians to resist auscultating the neck. Perhaps no physical finding in adults causes as much confusion as the presence of the carotid bruit in asymptomatic patients. Most clinical research suggests that there is a clear benefit to carotid endarterectomy for patients with symptoms and a benefit (although likely small) for asymptomatic patients.

Prior Probability for Carotid Stenosis

Symptomatic Patients

Prior Probability

After ruling out patients for whom endarterectomy would not be considered, 10% to 30% will have surgically amenable carotid stenosis. There is variability in the estimates of the remaining patients who will prove to have surgically correctable carotid stenosis. The variability depends on the patient population, criteria for determining surgical risk, and the threshold for defining an “important” stenosis.

Asymptomatic Patients

Prior Probability

For patients 60 years or older, there is 1% to 10% probability for carotid stenosis.

The prevalence of carotid stenosis increases from approximately 0.5% for patients 50 years of age to approximately 10% by age 90 years.14 For patients older than 65 years, 5% to 7% of women and 7% to 10% of men will have a carotid stenosis of 50% or higher. For more significant degrees of stenosis, 2 prospective, population-based samples show that 1% to 2.3% of women and 1% to 4.1% of men older than 60 years will have a stenosis of 75% to 99%.15, 16

Population for Whom the Carotid Bruit Might Be Auscultated

  • Patients with cerebrovascular symptoms compatible with a nondebilitating stroke or TIA

  • Older patients, as part of an assessment for cardiovascular risk

Detecting the Likelihood of Carotid Stenosis

The presence of a carotid bruit does increases the likelihood of an important stenotic lesion, but the absence of a bruit (especially in patients with atherosclerotic risk factors) does not rule out carotid stenosis (see Tables 9-5 and 9-6).

Table 9-5Do Carotid Bruits Predict Stenosis in Symptomatic Patients?
Table 9-6Do Carotid Bruits Increase the Likelihood of Carotid Stenosis in Asymptomatic Patients?

Reference Standard Tests

  • Carotid duplex ultrasonography

  • Carotid Doppler ultrasonography

  • Magnetic resonance angiogram


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