What is the recommended preoperative imaging protocol for patients undergoing carotid endarterectomy (CEA)?

Preoperative Imaging Protocol for Carotid Endarterectomy

Doppler ultrasound scanning should be used as the first-line imaging modality for all patients undergoing evaluation for carotid endarterectomy, with additional imaging reserved for specific clinical scenarios. 1

Primary Imaging Assessment

Doppler Ultrasound (DUS)

• DUS is recommended as the initial imaging modality for all patients being evaluated for carotid endarterectomy 1
• Benefits include:
  • Non-invasive
  • No radiation exposure
  • High sensitivity (92.3%) and specificity (89%) for detecting significant stenosis 2
  • Cost-effective and widely available
  • Can be performed as an outpatient procedure
• The North American Symptomatic Carotid Endarterectomy Trial (NASCET) method should be used to assess internal carotid artery stenosis 1

Secondary Imaging (When Needed)

Additional imaging is indicated in the following scenarios:

When to Add CT Angiography (CTA) or MR Angiography (MRA):

• When DUS results are inconclusive or technically inadequate 1
• When carotid stenosis by ultrasound is >70% and revascularization is contemplated 1
• When there are discordant clinical and ultrasound findings 1
• For complex anatomical assessment prior to intervention 1

When to Consider Conventional Angiography:

• Only when DUS and CTA/MRA yield discordant results 1
• When DUS and CTA/MRA are not feasible 1
• Conventional angiography is no longer considered routine before CEA 1, 3

Special Clinical Scenarios

Symptomatic Patients (TIA or Stroke within 6 months)

• Complete imaging workup should be expedited (within 14 days) 1
• DUS followed by prompt CTA/MRA if stenosis >50% is detected 1
• Carotid revascularization is recommended for 70-99% stenosis 1
• May consider revascularization for 50-69% stenosis depending on patient factors 1

Asymptomatic Patients

• DUS is sufficient for initial evaluation 4
• Additional imaging with CTA/MRA if:
  • Bilateral 70-99% carotid stenosis is detected
  • 70-99% stenosis with contralateral occlusion
  • 70-99% stenosis with ipsilateral silent cerebral infarction 1

Patients Undergoing CABG

• DUS is recommended in patients with:
  • History of stroke/TIA
  • Carotid bruit
  • Age >70 years
  • Multivessel coronary artery disease
  • Peripheral arterial disease 1, 4

Imaging Protocol Quality Considerations

• Vascular laboratories should validate their own DUS criteria against CTA/MRA 2
• Sensitivity and specificity of DUS improve to 98.7% and 94.1% when both peak systolic velocity and end diastolic velocity are assessed 2
• DUS should be performed by experienced technicians and interpreted by specialists familiar with carotid disease 3, 5

Post-Operative Imaging Surveillance

• DUS is recommended within the first month after CEA 1
• Follow-up DUS at 6 months and then annually to assess patency and detect new lesions 1
• Once stability is established over an extended period, surveillance intervals may be lengthened 1
• Surveillance may be discontinued when the patient is no longer a candidate for intervention 1

Common Pitfalls to Avoid

• Relying solely on DUS without validating laboratory accuracy
• Delaying imaging in symptomatic patients (should be completed within 14 days)
• Performing unnecessary conventional angiography when non-invasive imaging is adequate
• Failing to use the NASCET method for stenosis measurement
• Using the European Carotid Surgery Trial (ECST) method, which is not recommended 1

By following this evidence-based imaging protocol, clinicians can effectively evaluate patients for carotid endarterectomy while minimizing unnecessary testing, reducing procedural risks, and optimizing patient outcomes.