Carotid Endarterectomy Stenosis Thresholds
For symptomatic patients with 70-99% carotid stenosis, carotid endarterectomy should be performed urgently, while those with 50-69% stenosis receive moderate benefit; asymptomatic patients require 60-99% stenosis to justify surgery, but only when perioperative complication rates are exceptionally low (<3%). 1
Symptomatic Carotid Stenosis
70-99% Stenosis (Strong Indication)
- Carotid endarterectomy provides a 16% absolute risk reduction in stroke over 5 years compared to medical therapy alone 2, 3
- Surgery must be performed urgently, ideally within the first few days after TIA or nondisabling stroke 1
- Maximum acceptable delay is 14 days from the ischemic event for patients not clinically stable initially 1, 4
- The surgeon/center must demonstrate perioperative stroke and death rates ≤6-7% 1, 4
50-69% Stenosis (Moderate Indication)
- Surgery yields only a modest 4.6% absolute risk reduction at 5 years 2, 3
- To prevent one ipsilateral stroke over 5 years, 15 patients must undergo surgery 3
- Benefit is greatest in men, patients with recent hemispheric stroke (not just TIA), and those with hemispheric rather than retinal symptoms 3
- Exceptional surgical skill is mandatory—perioperative complication rates must be <6% to justify the procedure 3, 5
<50% Stenosis (No Benefit)
- Carotid endarterectomy is not indicated; patients did not benefit from surgery in randomized trials 2, 3
- Medical management alone is appropriate 6
Asymptomatic Carotid Stenosis
60-99% Stenosis (Selective Indication)
- Surgery reduces stroke risk from approximately 2% per year to 1% per year 1
- The perioperative stroke/death rate must be <3%—this is non-negotiable 1, 2
- Patient must have life expectancy >5 years, as benefit accrues slowly over time 1
- Women appear to benefit less than men (17% vs 66% risk reduction), partly due to higher perioperative complication rates in women (3.6% vs 1.7%) 1
Key Caveat for Asymptomatic Disease
Modern medical therapy (high-intensity statins, antihypertensives, antiplatelet agents) has substantially reduced stroke rates since the original trials were conducted 1, 7
- The benefit of surgery in the current era may be smaller than historical trials suggest 1, 7
- Aggressive medical management is mandatory regardless of whether surgery is performed 1
Critical Quality Benchmarks
Surgeon/Center Requirements
- Symptomatic patients: perioperative stroke/death rate must be <6-7% 1, 4
- Asymptomatic patients: perioperative stroke/death rate must be <3% 1, 2
- Centers must routinely audit and report their outcomes 1, 5
- If local complication rates exceed these thresholds, refer to a higher-volume center 4
Age Considerations
- Patients >70 years should undergo endarterectomy rather than carotid stenting, as stenting carries higher perioperative stroke/death risk in older patients 1, 4
- Very elderly patients (≥75 years) can safely undergo CEA with operative mortality of 0% and perioperative stroke rates of approximately 4.8% at experienced centers 4
Measurement Technique Matters
- Stenosis should ideally be measured by CTA using the NASCET method (comparing minimal residual lumen to distal internal carotid artery diameter, not the carotid bulb) 1
- The ECST method (comparing to carotid bulb) yields different percentages—a 70% NASCET stenosis corresponds to approximately 82% ECST stenosis 1
- Use NASCET criteria when applying these thresholds 1, 3
Common Pitfalls to Avoid
- Do not operate on symptomatic patients with <50% stenosis—perioperative risks exceed any potential benefit 6, 2, 3
- Do not proceed with asymptomatic CEA unless the surgeon can document <3% complication rates—otherwise medical therapy alone is superior 1, 2
- Do not delay surgery in symptomatic patients beyond 14 days—benefit declines rapidly after this window 1, 4
- Do not assume all asymptomatic stenoses require surgery—individual risk stratification (age, sex, life expectancy, comorbidities) is essential 1