What are the indications for carotid artery stenting (CAS)?

Indications for Carotid Artery Stenting (CAS)

Carotid artery stenting is indicated as an alternative to endarterectomy for symptomatic patients with ≥70% stenosis by noninvasive imaging (or ≥50% by catheter angiography) who are at average or low risk for endovascular complications, provided the anticipated periprocedural stroke or mortality rate is <6%. 1

Primary Indications by Stenosis Severity and Symptom Status

Symptomatic Patients (TIA or stroke within 6 months)

Stenosis ≥70% by noninvasive imaging or ≥50% by catheter angiography:

• CAS is a Class I indication (equivalent to CEA) for average or low-risk patients when performed by operators with documented periprocedural stroke/death rates <6% 1
• The procedure should ideally be performed within 2 weeks of the index neurological event 1

Stenosis 50-69%:

• CAS may be considered in select patients <70 years old, though CEA remains preferred 2
• Patient-specific factors including age, comorbidities, and anatomy should guide the decision 1

Stenosis <50%:

• There is absolutely no indication for CAS or any revascularization procedure (Class III recommendation) 1, 3

Asymptomatic Patients

Stenosis ≥60-70%:

• CAS might be considered in highly selected patients, but its effectiveness compared to medical therapy alone is not well established (Class IIb recommendation) 1
• The anticipated periprocedural complication rate must be <3% for asymptomatic patients 4
• Life expectancy should exceed 5 years 4

Specific Clinical Scenarios Favoring CAS Over CEA

Anatomic factors making surgery high-risk (Class IIa-IIb): 1

• Stenosis distal to the second cervical vertebra or proximal (intrathoracic) location
• Previous ipsilateral CEA with restenosis
• Contralateral vocal cord paralysis
• Previous radical neck surgery or neck irradiation
• Radiation-induced stenosis

Medical comorbidities are NOT reliable indicators for CAS preference:

• Recent evidence questions whether medical "high-risk" criteria justify CAS over CEA 5
• Symptomatic patients with medical comorbidities actually have worse outcomes with CAS compared to CEA 6

Critical Contraindications and Cautions

Age >70 years is a relative contraindication to CAS: 7, 4

• CEA demonstrates superior outcomes in older patients
• Stroke risk: 1% for CEA versus 3% for CAS in this population 7

Operator and center requirements are mandatory: 1, 7

• Documented periprocedural morbidity/mortality rates of 4-6% for symptomatic patients
• The center must routinely audit performance results
• If these benchmarks cannot be met, CAS should not be offered

Absolute contraindications: 1

• Chronic total occlusion of the carotid artery
• Severe disability from cerebral infarction precluding preservation of useful function
• Stenosis <50% (except in extraordinary circumstances)

Mandatory Concurrent Medical Management

All patients undergoing CAS must receive aggressive medical therapy regardless of revascularization: 3, 7, 4

• Antiplatelet therapy (dual antiplatelet therapy for at least 21 days post-procedure, then single agent) 3
• High-intensity statin therapy 3, 7
• Blood pressure control 3, 7
• Smoking cessation and diabetes management 4

Key Evidence Considerations

The SAPPHIRE trial demonstrated non-inferiority of CAS to CEA in high-surgical-risk patients, with 30-day event rates of 5.8% for CAS versus 12.6% for CEA 1. However, the CREST trial showed age-dependent outcomes: CAS performed better in patients <70 years, while CEA was superior in those >70 years 1. More recent population-based studies confirm that symptomatic patients have significantly worse outcomes with CAS (8.3% combined stroke/mortality) compared to CEA (4.6%), while asymptomatic patients show equivalent outcomes 6.

Common Pitfalls to Avoid

• Do not offer CAS to symptomatic patients >70 years old unless there are compelling anatomic contraindications to surgery 7, 4
• Do not confuse medical comorbidities with appropriate CAS indications in symptomatic patients—these patients actually do worse with CAS 6
• Do not proceed with CAS if your center cannot document appropriate complication rates—this is a hard requirement, not a suggestion 1, 7
• Do not forget that embolic protection devices should be used in the vast majority of cases 1, 8