What is the guideline for treating carotid (carotid artery) stenosis?

Management of Carotid Artery Stenosis

All patients with carotid stenosis require intensive medical therapy regardless of stenosis severity or symptom status, and revascularization decisions depend critically on whether the patient is symptomatic (ipsilateral retinal or hemispheric ischemic symptoms within 6 months) and the degree of stenosis. 1, 2

Initial Assessment and Diagnosis

• Perform duplex ultrasonography (DUS) as first-line imaging to diagnose and quantify internal carotid artery stenosis using the NASCET method (stenosis = [1 - N/D] × 100%, where N is diameter at maximum stenosis and D is diameter of distal internal carotid artery where walls become parallel). 1, 3

• If DUS is equivocal or inconclusive, obtain CTA or MRA for definitive assessment of stenosis severity and extent. 1, 4

• All patients require neurological evaluation by a vascular team including a neurologist to determine symptom status and assess for recent ischemic events. 1

• Define symptomatic status as ipsilateral retinal or hemispheric ischemic symptoms (TIA or stroke) within the past 6 months; asymptomatic patients have no such symptoms. 1, 3

Optimal Medical Therapy (Mandatory for All Patients)

Antiplatelet Therapy

For asymptomatic patients:

• Initiate aspirin 75-325 mg daily OR clopidogrel 75 mg daily as single antiplatelet therapy for long-term management. 2, 1

For symptomatic patients not undergoing immediate revascularization:

• Start dual antiplatelet therapy (DAPT) with aspirin plus clopidogrel 75 mg daily for at least 21 days, then transition to single antiplatelet therapy (aspirin 81-325 mg daily or clopidogrel 75 mg daily) for long-term secondary prevention. 1, 2, 5

Lipid Management

• Prescribe high-dose statin therapy with atorvastatin 80 mg daily to achieve LDL cholesterol <70 mg/dL in all patients regardless of symptom status. 1, 2, 4

Blood Pressure Control

• Target blood pressure <140/90 mmHg for all patients with carotid stenosis. 1, 2

Risk Factor Modification

• Mandate smoking cessation as tobacco use is a major independent risk factor for stroke. 1, 2
• Optimize diabetes management to reduce cardiovascular risk. 5

Revascularization Decisions

Symptomatic Carotid Stenosis (≥50% stenosis)

For 70-99% stenosis:

• Perform carotid endarterectomy (CEA) within 14 days of symptom onset provided the 30-day risk of procedural death/stroke is documented <6%. 1, 3
• The NASCET trial demonstrated that CEA reduces 2-year ipsilateral stroke risk from 26% to 9% in this population, with 5-year rates of 15.7% versus 22% for medical therapy alone. 3

For 50-69% stenosis:

• CEA is reasonable but provides more modest benefit (absolute risk reduction of 6.5% over 5 years, requiring treatment of 77 patients to prevent one stroke). 3

For <50% stenosis:

• Do not perform revascularization—carotid intervention is not recommended except in extraordinary circumstances. 3, 1

Asymptomatic Carotid Stenosis

For 60-99% stenosis:

• CEA may be considered in highly selected patients with life expectancy >5 years, age <75 years, and documented perioperative stroke/death risk <3%, but the benefit is modest (absolute 5-year risk reduction of 6%, requiring treatment of 84 patients to prevent one stroke). 3, 6
• Modern intensive medical therapy has dramatically improved outcomes for asymptomatic patients, with annual stroke risk now <1% per year, making the benefit of prophylactic CEA increasingly marginal. 4, 6

For <60% stenosis:

• Do not perform revascularization—continue intensive medical therapy alone. 3, 1

Carotid Artery Stenting (CAS) Considerations

• CAS may be considered as an alternative to CEA in high surgical risk patients (prior neck surgery/radiation, contralateral vocal cord paralysis, high/intrathoracic lesions, age ≥80 years, severe cardiac/pulmonary comorbidities) with 60-99% symptomatic stenosis. 1, 3
• Registry data shows higher 1-year stroke/death rates with CAS (9.7%) versus CEA (5.2%) in symptomatic patients, making CEA the preferred approach when surgical risk is acceptable. 7, 3

Perioperative Antiplatelet Management

For patients undergoing CEA:

• Continue aspirin 75-325 mg daily perioperatively to reduce perioperative stroke risk. 1, 3
• Do not routinely add clopidogrel unless the patient is already on DAPT for recent symptomatic disease. 8

For patients undergoing CAS:

• Administer DAPT with aspirin 81-325 mg plus clopidogrel 75 mg daily for at least 30 days before and after CAS to reduce thromboembolic complications. 3, 1, 8
• Embolic protection device deployment during CAS is beneficial when vascular injury risk is low. 3

Special Clinical Scenarios

Contralateral Carotid Occlusion

• Do not withhold CEA based solely on contralateral occlusion—this is a high-risk feature that increases stroke risk with medical management alone, and the benefit of CEA may be even more pronounced in this subgroup. 7
• Perform CEA within 14 days of symptom onset in symptomatic patients with 70-99% stenosis and contralateral occlusion. 7

Chronic Total Occlusion

• Do not perform revascularization in patients with chronic total occlusion of the targeted carotid artery. 3

Severe Disability from Prior Stroke

• Do not perform revascularization when severe disability (Modified Rankin Scale ≥3) precludes preservation of useful function. 3

Recurrent Stenosis

• Repeat CEA or perform CAS is reasonable for symptomatic patients with recurrent stenosis due to intimal hyperplasia or atherosclerosis using the same criteria as initial revascularization. 3
• Do not perform reoperative CEA or CAS in asymptomatic patients with <70% stenosis that has remained stable over time. 3

Surveillance Protocol

• Perform DUS surveillance within the first month after revascularization, then at 6 months, and annually thereafter to assess patency and detect new or contralateral lesions. 3, 1
• Annual follow-up is mandatory for all patients with assessment of neurological symptoms, cardiovascular risk factors, and medication adherence. 1, 2
• Once stability is established over an extended period, surveillance at extended intervals may be appropriate, and termination of surveillance is reasonable when the patient is no longer a candidate for intervention. 3

Critical Pitfalls to Avoid

• Do not delay CEA beyond 14 days in symptomatic patients—the benefit of surgery decreases substantially with time from symptom onset. 1, 7
• Do not perform CEA if the institutional perioperative stroke/death rate exceeds 6% for symptomatic patients or 3% for asymptomatic patients—the risks outweigh benefits above these thresholds. 1, 3
• Do not use long-term DAPT in asymptomatic patients—reserve combination antiplatelet therapy only for symptomatic patients in the acute period (21 days) or perioperatively for CAS. 2, 1
• Do not screen and operate on all asymptomatic patients with ≥60% stenosis—the number needed to treat exceeds 100 per year to prevent one stroke, making routine screening and prophylactic surgery unjustified. 6