II. Exam
- See Bruit
- Findings in which Carotid Bruit is more suggestive of significant carotid lesion
- Diastolic component is the only characteristic reliably specific for significant Carotid Bruit
- Carotid Bruit AND symptoms suggestive of Carotid Stenosis
- Degree of stenosis by atherosclerotic Plaque
- Minimum stenosis causing bruit: 50% (<3 mm lumen)
- Prolonged, high-pitched bruit: >75% (1.5 mm lumen)
- Location
- Plaque involves posterior wall of common carotid
- Affects bifurcation and flow into internal carotid
- Risk of distal thrombus formation in internal carotid
III. Differential Diagnosis
- Carotid Stenosis
- Cardiac Murmur transmission
- External Carotid Stenosis
- Venous Hum
- Tortuous Arteries
IV. Interpretation
- Carotid Bruit associated risk of stroke at 1 year
- Asymptomatic Carotid Bruit: 1% risk at 1 year
- Transient Ischemic Attack history: 1.7% risk
- Other studies question bruit significance
V. Efficacy
- Carotid Bruit has poor efficacy
- Test Sensitivity: 40% for those with >50% Carotid Stenosis
- False Positives: 10% with Carotid Bruits have <50% Carotid Stenosis
VI. References
- Brown (2017) Stroke and Cerebrovascular Disease Update, Mayo Clinical Reviews, Rochester
- Firnhaber (2022) Am Fam Physician 105(1): 65-72 [PubMed]