What is the treatment for significant carotid stenosis, defined as 70% or greater narrowing of the carotid artery?

Significant Carotid Stenosis: Definition and Treatment

Definition of Significant Stenosis

Significant carotid stenosis is defined as ≥70% narrowing by NASCET (North American Symptomatic Carotid Endarterectomy Trial) method, which is the recommended standard for measurement. 1

• The NASCET method compares stenosis diameter to the distal internal carotid artery, not the carotid bulb 1
• Stenosis of 50-69% is considered moderate and may warrant intervention in symptomatic patients 1
• The ECST (European Carotid Surgery Trial) method should NOT be used as it overestimates stenosis severity 1
• Duplex ultrasound (DUS) is the recommended first-line imaging modality for diagnosis 1

Treatment Approach: Symptomatic vs Asymptomatic

Symptomatic Carotid Stenosis (Recent stroke/TIA)

For symptomatic patients with 70-99% stenosis, carotid endarterectomy (CEA) is strongly recommended and should be performed within 14 days of symptom onset, ideally within the first few days. 1, 2

Medical Management (ALL symptomatic patients):

• Dual antiplatelet therapy (DAPT) with aspirin and clopidogrel 75mg for at least 21 days if not undergoing immediate revascularization 1
• High-potency statin therapy 1
• Blood pressure control 1
• Smoking cessation and lifestyle modification 1

Surgical Intervention Criteria:

• CEA is indicated for 70-99% stenosis if perioperative stroke/death risk is <6% 1
• For 50-69% stenosis, CEA provides modest benefit (4.6% absolute risk reduction at 5 years) and may be considered if perioperative risk remains <6% 1, 2
• Surgery is most effective when performed urgently—within 48 hours once neurologically stable, but definitely within 14 days 1, 3
• CEA provides 16% absolute risk reduction at 5 years for severe symptomatic stenosis (NNT=6) 2

Asymptomatic Carotid Stenosis

For asymptomatic patients, optimal medical therapy is now the primary treatment, as contemporary stroke risk has fallen to ≤1% per year with modern medical management. 4

Medical Management (Primary approach):

• Daily aspirin and statin therapy 1, 4
• Aggressive cardiovascular risk factor control (blood pressure, diabetes, smoking cessation) 1, 4
• Annual duplex ultrasound surveillance 1, 4
• Annual follow-up for treatment compliance 1

Selective Revascularization:

• CEA may be considered for 70-99% stenosis ONLY if perioperative stroke/death risk is <3% AND life expectancy >5 years 1, 4
• Routine revascularization is NOT recommended in patients with life expectancy <5 years or absence of high-risk features 1
• The benefit is marginal: approximately 1% annual stroke risk with CEA versus 1-2% with medical therapy alone in contemporary practice 4, 2
• Patient must understand that only 5 out of 100 operated patients will benefit from stroke prevention over 5 years 5

CEA vs Carotid Artery Stenting (CAS)

CEA is definitively superior to CAS, especially in patients over 70 years old. 2

• CEA has lower periprocedural stroke rates: 1% versus 3% for CAS in older patients 2
• CEA mortality rate is 0.44% with stroke rate of 0.95% in large registries 2
• CAS perioperative risk is 2.2-4% in asymptomatic patients versus 1.5-3% for CEA 4
• CEA is particularly recommended for patients with calcified plaques 2

Post-Intervention Management

After CEA or CAS:

• DAPT with aspirin and clopidogrel for at least 1 month after stenting 1
• Long-term aspirin or clopidogrel indefinitely 1
• Duplex ultrasound surveillance within the first month 1
• Continue aggressive cardiovascular risk factor management 1, 2

Critical Quality Benchmarks

Centers performing carotid revascularization must routinely audit their outcomes to ensure perioperative stroke/death rates remain <6% for symptomatic and <3% for asymptomatic patients. 2

• These thresholds are absolute requirements to maintain favorable benefit-risk ratios 1, 2
• If institutional rates exceed these benchmarks, medical therapy alone is superior 2

Common Pitfalls to Avoid

• Do not use ECST measurement method—it overestimates stenosis 1
• Do not delay CEA beyond 14 days in symptomatic patients—benefit decreases significantly 1, 3
• Do not perform routine revascularization in asymptomatic patients without careful risk stratification and discussion of marginal benefits 1, 4
• Do not offer CAS to patients over 70 years old when CEA is feasible 2
• Do not intervene on stenosis <50% in any patient—no benefit demonstrated 1