What is the recommended management of internal carotid artery atherosclerosis, including risk‑factor modification, antiplatelet and statin therapy, and criteria for carotid endarterectomy or stenting?

Treatment for Internal Carotid Artery Atherosclerosis

All patients with ICA atherosclerosis require optimal medical therapy including antiplatelet agents, high-intensity statins, and aggressive cardiovascular risk factor modification, with revascularization reserved for symptomatic patients with ≥50% stenosis or carefully selected asymptomatic patients with ≥60% stenosis and high-risk features. 1

Medical Management (Foundation for All Patients)

Antiplatelet Therapy

Symptomatic ICA Stenosis:

• Dual antiplatelet therapy (DAPT) with aspirin and clopidogrel 75 mg is mandatory for the first 21 days or longer in symptomatic patients not undergoing immediate revascularization, followed by long-term single antiplatelet therapy (clopidogrel 75 mg or aspirin). 1, 2
• This early DAPT strategy is particularly critical in minor strokes to reduce recurrent stroke risk during the highest-risk period. 1

Asymptomatic ICA Stenosis:

• Long-term low-dose aspirin should be considered for asymptomatic patients with >50% stenosis who have low bleeding risk, given their doubled risk of myocardial infarction. 1
• DAPT offers no benefit over single antiplatelet therapy in asymptomatic disease. 1

Lipid Management

• High-intensity statin therapy is recommended for all patients with carotid stenosis to stabilize plaque and reduce cardiovascular events. 1
• Target total cholesterol <200 mg/dL, though aggressive LDL reduction is the primary goal. 1

Blood Pressure Control

• Target blood pressure <140/90 mmHg to slow stenosis progression and reduce stroke risk. 1
• Permissive hypertension (SBP 140-160 mmHg) may be warranted acutely in severe stenosis to maintain cerebral perfusion. 3

Risk Factor Modification

• Smoking cessation is mandatory. 1
• Diabetes optimization with target HbA1c individualized but generally <7%. 1
• Regular physical activity and dietary modification targeting Mediterranean-style diet. 4

Revascularization Criteria

Symptomatic ICA Stenosis (Recent TIA or Stroke Within 6 Months)

Severe Stenosis (70-99%):

• Carotid endarterectomy (CEA) is recommended if perioperative stroke/death risk is <6%. 1
• Timing is critical: perform CEA within 14 days of symptom onset, ideally within 2 weeks. 1, 5
• Carotid artery stenting (CAS) is an alternative for patients <70 years old or those with high surgical risk (radiation-induced stenosis, restenosis after CEA, surgically inaccessible lesions). 1, 5

Moderate Stenosis (50-69%):

• CEA is recommended but benefit depends on patient-specific factors including age, sex, comorbidities, and life expectancy. 1
• CAS may be considered as alternative in younger patients (<70 years). 5

Mild Stenosis (<50%):

• Revascularization is not recommended; medical therapy alone is indicated. 1

Asymptomatic ICA Stenosis

High-Risk Features Present (≥60% stenosis):

• Revascularization may be considered only in highly selected patients with:
  • Life expectancy >5 years 1
  • High-risk plaque features: intraplaque hemorrhage, lipid-rich necrotic core, echolucent plaques, spontaneous embolization on transcranial Doppler, impaired cerebrovascular reserve, contralateral TIA/stroke, ipsilateral silent infarction, or stenosis progression >20% 1
  • Documented perioperative stroke/death risk <3% for optimal benefit 1

Routine Revascularization Not Recommended:

• Asymptomatic patients without high-risk features should not undergo routine revascularization, as modern medical therapy has reduced annual stroke risk to <1%. 1, 6
• The SPACE-2 trial showed no clear benefit of revascularization over optimal medical therapy alone in asymptomatic disease. 1

Diagnostic Assessment

Initial Imaging

• Duplex ultrasound (DUS) is the first-line imaging modality to diagnose ICA stenosis. 1
• Use NASCET method (or non-invasive equivalent) to quantify stenosis severity; ECST method overestimates stenosis and should not be used. 1
• Peak systolic velocity >230 cm/s indicates ≥70% stenosis; 125-230 cm/s indicates 50-69% stenosis. 1

Confirmatory Imaging

• CT angiography (CTA) or MR angiography (MRA) should be obtained when DUS findings are inconclusive or to plan revascularization. 1, 3
• Catheter angiography reserved for cases where non-invasive imaging fails to define stenosis severity or when intervention is planned. 1

Post-Revascularization Management

After CEA or CAS

• DAPT with aspirin and clopidogrel for at least 1 month after CAS. 1, 2
• Long-term single antiplatelet therapy (aspirin or clopidogrel) is recommended indefinitely after any revascularization. 1, 2
• DUS surveillance within the first month to assess for complications. 1, 2

Follow-Up Protocol

• Annual follow-up to assess neurological symptoms, cardiovascular risk factors, and medication adherence. 1, 2
• Serial imaging every 3-6 months in the first year if high-risk features persist. 3

Critical Pitfalls to Avoid

• Do not delay revascularization beyond 14 days in symptomatic patients with ≥50% stenosis—stroke risk is highest in the first two weeks. 1
• Do not withhold antiplatelet therapy perioperatively in severe stenosis—thrombotic risk outweighs bleeding risk. 3
• Do not use ECST method for stenosis quantification—it systematically overestimates severity and may lead to inappropriate intervention. 1
• Do not prematurely discontinue DAPT after CAS—stent thrombosis risk is substantial in the first month. 2
• Do not perform revascularization in asymptomatic patients without documented high-risk features and life expectancy >5 years—modern medical therapy alone is often sufficient. 1
• Do not assume stable neurological exam means stable vascular status—severe multi-segment stenosis requires urgent imaging even without symptoms. 3

Multi-Disciplinary Decision-Making

• Symptomatic ICA stenosis patients should be assessed by a Neuro-Vascular Team including neurologists, vascular surgeons, and interventionalists to determine optimal revascularization strategy. 1
• Patient-centered shared decision-making should incorporate individual stroke risk, procedural risks, local expertise, and patient preferences. 1