At what percentage of stenosis is surgical intervention recommended for symptomatic and asymptomatic carotid artery disease?

Surgical Intervention Thresholds for Carotid Artery Stenosis

For symptomatic carotid stenosis, operate at ≥70% stenosis (Class I recommendation), and consider surgery for 50-69% stenosis in select patients; for asymptomatic stenosis, consider surgery at ≥60% stenosis only in carefully selected patients with life expectancy >5 years and documented surgical complication rates <3%. 1

Symptomatic Carotid Stenosis

Severe Stenosis (70-99%)

• Carotid endarterectomy (CEA) should be performed for symptomatic stenosis of 70-99% with documented perioperative stroke/death rates <6% 1
• Surgery provides the greatest benefit when performed within 14 days of symptom onset, ideally within the first few days after the patient is neurologically stable (after 48 hours) 1
• Approximately 90% of contemporary guidelines endorse CEA as routine treatment for this degree of stenosis 1
• The absolute risk reduction is substantial: 2-year ipsilateral stroke risk of 9% with CEA versus 26% with medical therapy alone 1

Moderate Stenosis (50-69%)

• CEA should be considered for symptomatic stenosis of 50-69%, though the benefit is more modest than for severe stenosis 1
• Approximately 45% of guidelines recommend CEA should be provided routinely, while 55% state it may be provided for this degree of stenosis 1
• Surgery is particularly beneficial in men, patients aged ≥75 years, those with hemispheric (versus retinal) symptoms, and those treated within 2 weeks of symptoms 1, 2

Mild Stenosis (<50%)

• Revascularization is not recommended for stenosis <50% (Class III, Level A) 1, 3
• Medical therapy alone is the appropriate management 3

Timing Considerations

• CEA should ideally be performed within the first days following nondisabling stroke or TIA, and definitely within 14 days of symptom onset 1
• Avoid surgery within the first 48 hours in patients with acute carotid occlusion, major neurological deficit, large middle cerebral artery infarction (>1/3 territory), pre-existing hemorrhage, or impaired consciousness 1

Asymptomatic Carotid Stenosis

Moderate to Severe Stenosis (60-99%)

• CEA may be considered for asymptomatic stenosis of 60-99% in highly selected patients 1
• Critical selection criteria include:
  • Life expectancy >5 years 1
  • Documented perioperative stroke/death rate <3% 1
  • Presence of high-risk features (age >75 years, male sex, irregular stenosis, contralateral occlusion, tandem intracranial stenosis) 1
• Approximately 86% of guidelines endorse CEA for asymptomatic stenosis of 50-99%, though most specify it "may be provided" rather than "should be provided" 1
• The absolute benefit is modest: surgery reduces stroke risk from approximately 2% per year to 1% per year, or from 11% to 6% over 5 years 1, 4, 5

When NOT to Operate

• Routine revascularization is not recommended in asymptomatic patients without high-risk features and with life expectancy <5 years (Class III, Level A) 1
• The number needed to treat is high: only 5 of 100 patients operated will benefit from avoiding a stroke over 5 years 5

CEA versus Carotid Artery Stenting (CAS)

Symptomatic Patients

• CEA is generally preferred over CAS for patients >70 years of age who are otherwise fit for surgery, as stenting carries higher perioperative stroke risk in older patients 1
• CAS may be considered for high surgical risk patients due to anatomic factors (high stenosis, radiation-induced stenosis, contralateral vocal cord paralysis) or medical comorbidities, provided perioperative complication rates remain <6% 1
• For average surgical risk symptomatic patients, approximately 58% of guidelines endorse CAS as an option, though 27% oppose it 1

Asymptomatic Patients

• CAS may be considered in asymptomatic high-risk surgical patients with 60-99% stenosis and high-risk features, but only if perioperative complication rates are <3% 1
• Approximately 61% of guidelines endorse CAS for asymptomatic stenosis, while 29% oppose it 1

Critical Quality Metrics

Surgeon/Center Requirements

• The operating surgeon/center must routinely audit performance results and demonstrate:
  • <6% perioperative stroke/death rate for symptomatic patients 1
  • <3% perioperative stroke/death rate for asymptomatic patients 1
• These thresholds are non-negotiable; benefits of surgery are negated if complication rates exceed these levels 1

Medical Management (Always Required)

All Patients Regardless of Stenosis Severity

• Optimal medical therapy is mandatory for all patients with carotid stenosis, whether or not they undergo revascularization 1, 3
• For symptomatic patients not undergoing immediate revascularization: dual antiplatelet therapy (aspirin + clopidogrel 75 mg) for at least 21 days, then single antiplatelet therapy long-term 1
• Statin therapy to stabilize plaques 3
• Aggressive blood pressure control 3
• Smoking cessation and diabetes management 3

Common Pitfalls to Avoid

• Do not operate on asymptomatic stenosis without documenting <3% complication rates – the modest benefit is easily negated by higher complication rates 1
• Do not delay surgery beyond 14 days in symptomatic patients – the highest stroke risk is in the first 2 weeks after symptoms 1
• Do not use CAS routinely in patients >75 years – CEA is safer in this age group 1
• Do not forget that medical therapy has dramatically improved – contemporary stroke risk with medical therapy alone for asymptomatic stenosis is approximately 1% per year, much lower than in historical trials 1, 6
• Use NASCET method for stenosis measurement, not ECST method 1
• Duplex ultrasound is first-line imaging, with CTA or MRA for confirmation when surgical decision-making is needed 1

Follow-Up Requirements

• Annual follow-up to assess neurological symptoms, cardiovascular risk factors, and medication adherence 1
• Duplex ultrasound surveillance within the first month after revascularization, then periodically to assess for restenosis 1, 3
• After CEA or CAS, dual antiplatelet therapy for at least 1 month, then long-term single antiplatelet therapy 1