Exam

Carotid Bruit

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Carotid Bruit, Carotid Artery Stenosis, Carotid Stenosis

  • Technique
  • Interpretation
  • Carotid Bruit
  1. Findings in which Carotid Bruit is more suggestive of significant carotid lesion
    1. Diastolic component is the only characteristic reliably specific for significant Carotid Bruit
    2. Carotid Bruit AND symptoms suggestive of Carotid Stenosis
  2. Degree of stenosis by atherosclerotic Plaque
    1. Minimum stenosis causing bruit: 50% (<3 mm lumen)
    2. Prolonged, high-pitched bruit: >75% (1.5 mm lumen)
  3. Location
    1. Plaque involves posterior wall of common carotid
    2. Affects bifurcation and flow into internal carotid
    3. Risk of distal thrombus formation in internal carotid
  4. Carotid Bruit associated risk of stroke at 1 year
    1. Asymptomatic Carotid Bruit: 1% risk at 1 year
    2. Transient Ischemic Attack history: 1.7% risk
    3. Other studies question bruit significance
  5. Carotid Bruit has poor efficacy
    1. Test Sensitivity: 40% for those with >50% Carotid Stenosis
    2. False Positives: 10% with Carotid Bruits have <50% Carotid Stenosis
  6. References
    1. Brown (2017) Stroke and Cerebrovascular Disease Update, Mayo Clinical Reviews, Rochester
  • Symptoms
  1. Contralateral weakness or numbness
  2. Ipsilateral blindness
  3. Dominant hemisphere involvement
    1. Dysphasia
    2. Aphasia
    3. Apraxia
  • Imaging
  • Preferred First-Line Studies
  1. Carotid Artery Duplex Ultrasonography
    1. Standard first-line diagnostic tool for Carotid Stenosis
      1. However, do not make clinical decisions based on Ultrasound alone (due to false positives)
      2. Confirm findings with either a MRA or CTA
    2. Less expensive than MRA
    3. Accuracy for diagnosing severe Carotid Stenosis
      1. Test Sensitivity: 86%
      2. Test Specificity: 87%
  2. Carotid Magnetic Resonance Angiography (MRA)
    1. Better than Ultrasound at defining carotid anatomy
    2. Accuracy for diagnosing severe Carotid Stenosis
      1. Test Sensitivity: 95%
      2. Test Specificity: 90%
  3. References
    1. Nederkoorn (2003) Stroke 34:1324-32 [PubMed]
  • Imaging
  • Other studies
  1. CT Angiography with 3D reconstruction
    1. Requires intravenous iodinated contrast exposure
    2. Emerging technology that has not been fully evaluated
    3. Significant radiation exposure
  2. Angiography
    1. Gold standard which allows evaluation of the entire carotid system
    2. Invasive procedure with risk of neurologic complications
    3. Now used primarily to resolve imaging discrepancies in perioperative period
  • Management
  • Symptomatic Carotid Stenosis
  1. Endarterectomy carries risk of significant morbidity
    1. Cognitive changes may be difficult to discern
    2. Risk of CVA within 30 days of procedure: 7%
  2. Symptomatic patient with Carotid Stenosis >70%
    1. Intervention offers greatest benefit (17% Absolute Risk Reduction at 2 years per NASCET study)
    2. Significant benefit from carotid endarterectomy
    3. Benefits include patients over age 75 years
  3. Symptomatic patient with Carotid Stenosis 50 to 69%
    1. Benefit from carotid endarterectomy
    2. Benefits include patients over age 75 years
  4. Symptomatic patient with Carotid Stenosis <50%
    1. No benefit from carotid endarterectomy
    2. See Prevention of Ischemic Stroke
  • Management
  • Asymptomatic Carotid Stenosis >60%
  1. Medical therapy: Indicated if Carotid Stenosis <80%
    1. Overall CVA Risk on medical therapy: 12% CVA 5 year risk
    2. See Prevention of Ischemic Stroke
    3. Hypertension control (typical goal is <130/80)
      1. Exercise caution with bilateral Carotid Stenosis
    4. Hyperlipidemia control with Statins
    5. Antiplatelet options
      1. Aspirin
      2. Other antiplatelet agents are not recommended
        1. Clopidogrel (Plavix)
          1. Do not use concurrently with Aspirin
        2. Aspirin with Dipyridamole (Aggrenox)
  2. Surgical Procedures: Indicated if Carotid Stenosis >80%
    1. Overall CVA Risk on surgical therapy: 6% CVA 5 year risk
    2. Relative contraindications to carotid endarterectomy
      1. Women show less benefit in asymptomatic Carotid Stenosis
      2. Life Expectancy <5 years
      3. Active cardiovascular disease
      4. Age over 80 years
      5. Concomitant intranial stenosis
      6. Contralateral Carotid Stenosis
    3. Surgical Options
      1. Carotid endarterectomy or
      2. Angioplasty, stent, distal protection
        1. As effective as carotid endarterectomy
        2. May be preferred in patients at high risk of complications due to comorbidity
          1. (2006) Lancet 368:1239-47 [PubMed]
          2. Park (2006) Am J Surg 192: 583-8 [PubMed]
        3. Recent European trials (SPACE and EVA-3S) showed high complication rate
          1. However these trials did not consistently use distal protection devices