01Purpose and principlesWhat the treatment does and how it fits into care.
Carotid artery stenting places an endovascular scaffold across an extracranial internal carotid stenosis, usually with cerebral embolic protection. It avoids surgical plaque removal and cranial-nerve dissection, but catheter passage through the arch and lesion, wire manipulation, ballooning and stent deployment can release emboli. CAS therefore cannot be reduced to a less invasive version of carotid endarterectomy: the procedures exchange different hazards. Randomised evidence shows more peri-procedural stroke with transfemoral CAS, whereas CEA causes more cranial nerve injury and local wound complications. The clinical value of preventing later ipsilateral stroke must exceed the immediate procedural risk.
Selection begins with the same question as CEA: is this patient likely to benefit from carotid revascularisation at all? Recent ipsilateral retinal or hemispheric symptoms, stenosis measured by a declared method, infarct burden, disability, haemorrhage, life expectancy and the centre's audited results determine eligibility. When intervention is indicated soon after TIA or nondisabling stroke, CEA remains the usual comparator and is generally preferred in the first fourteen days. CAS can become reasonable when prior neck irradiation, restenosis after CEA, a surgically inaccessible lesion, contralateral laryngeal-nerve palsy or severe cardiopulmonary disease increases surgical risk, provided endovascular anatomy and operator outcomes are acceptable. Increasing age, a tortuous or heavily diseased arch, severe calcification and very early transfemoral treatment may shift risk away from CAS.
Safe practice links technical planning to pharmacology. Aspirin plus clopidogrel is established before the procedure, with a clopidogrel loading option when treatment is urgent, and continues while the stent endothelialises. Intraprocedural anticoagulation and treatment of carotid-sinus bradycardia are governed by the interventional protocol. Afterwards, neurological observations, access-site review and active blood-pressure management seek embolic stroke, stent occlusion, hyperperfusion, bleeding and haemodynamic depression early. Duplex supplies a baseline and tests patency; later surveillance has value only when a finding could change treatment.
Key points
- Carotid stenting is selected through specialist multidisciplinary comparison with endarterectomy; age, timing, arch and lesion anatomy, prior neck treatment, comorbidity and local audited outcomes all matter.
- For recently symptomatic patients needing revascularisation within fourteen days, endarterectomy is generally preferred over transfemoral stenting because early procedural stroke or death is higher with stenting, especially from age seventy.
- New deficit, severe headache, seizure, hypertension, bradycardia or hypotension around stenting demands immediate assessment for embolism, thrombosis, haemorrhage, hyperperfusion or haemodynamic instability.
- Dual antiplatelet therapy with aspirin and clopidogrel must be planned before carotid stenting and continued for at least four weeks afterwards.
- After the dual phase, continue long-term antiplatelet monotherapy; prolonged aspirin plus clopidogrel needs a separate clinical indication because bleeding accumulates.
- Duplex defines the target lesion, while CTA or MRA maps the arch, access vessels, intracranial circulation and anatomical hazards that influence technique.
- Protection strategy, access route, stent design and need for ballooning are operator decisions rather than interchangeable textbook steps.
- Control post-procedural blood pressure and arrange duplex surveillance because both uncontrolled hypertension and hypotension can produce neurological harm.
02Indications, selection and cautionsWho may benefit, who needs urgent treatment and important alternatives.
Recent ipsilateral amaurosis fugax, retinal infarction, TIA or nondisabling hemispheric stroke supports symptomatic carotid disease after competing stroke mechanisms are assessed.
Previous neck radiotherapy, restenosis, a high cervical lesion, hostile neck surgery or contralateral recurrent-laryngeal-nerve palsy can increase CEA difficulty and favour discussion of CAS.
A severely diseased type III arch, marked vessel tortuosity, circumferential calcification or difficult access can increase embolic or access risk with transfemoral CAS.
Abrupt monocular loss, aphasia, neglect or contralateral weakness during wire passage or after deployment suggests thromboembolism or acute stent failure.
Bradycardia and hypotension during ballooning or after stenting reflect carotid-sinus stimulation and can compromise cerebral or myocardial perfusion.
New severe headache, seizure, hypertension, focal deficit or reduced consciousness after flow restoration requires urgent brain imaging and blood-pressure treatment.
03Assessment before treatmentTests and checks that guide safe selection.
Read from the initial assessment onwards. Tests may run in parallel in urgent care; first-line, preferred, confirmatory, definitive and gold-standard labels appear only when the chapter explicitly states them.
- 01
Accredited carotid duplex ultrasoundFirst step - Why
- Confirm stenosis severity, plaque location and flow while documenting the measurement criteria used.
- Interpretation and limitations
- Velocity must be integrated with the ICA-to-CCA ratio, end-diastolic velocity, plaque and distal flow; near occlusion may have unexpectedly low rather than high velocity.
- 02
CT angiography from arch to circle of Willis - Why
- Map access, aortic arch, lesion morphology, calcification and intracranial collateral circulation before intervention.
- Interpretation and limitations
- CTA can overestimate dense calcification and requires iodinated contrast; it also reveals tandem lesions and anatomy that may make transfemoral passage hazardous.
- 03
MR angiography and brain MRI - Why
- Clarify vascular anatomy and quantify recent infarction when MRI is available and clinically safe.
- Interpretation and limitations
- MRA avoids iodinated contrast but may overcall turbulent narrowing; diffusion imaging helps identify a large acute infarct that can change procedural timing.
- 04
Neurological baseline assessment - Why
- Document pre-procedure deficits and functional status for selection and reliable post-procedure comparison.
- Interpretation and limitations
- A new or worsened focal finding after stenting is not routine sedation and should trigger immediate stroke evaluation.
- 05
Full blood count, renal function and coagulation - Why
- Identify anaemia, thrombocytopenia, renal contrast risk and haemostatic factors affecting treatment safety.
- Interpretation and limitations
- Abnormal results modify contrast, antithrombotic and access plans; they do not independently establish carotid procedural benefit.
- 06
Post-stent duplex ultrasound - Why
- Establish stent patency and a velocity baseline for comparison during subsequent surveillance.
- Interpretation and limitations
- Native-artery velocity thresholds can overestimate in-stent stenosis; use validated laboratory criteria and compare with the early baseline.
04Treatment approachPreparation, options, escalation and aftercare.
01SELECTChoose the revascularisation methodFirst stepA patient has carotid disease for which revascularisation benefit is being considered.+
- 1Confirm that symptoms are ipsilateral and attributable, quantify neurological disability and infarct burden, and verify stenosis with the stated NASCET-equivalent method.
- 2Compare expected benefit with the centre's procedural risk, then weigh age, timing, neck factors, cardiopulmonary risk, arch anatomy and lesion morphology.
- 3Prefer CEA for most recently symptomatic patients treated within fourteen days, while considering CAS where surgical risk is higher and endovascular risk acceptable.
- 4Document the multidisciplinary decision, alternatives, material stroke and bleeding risks, antiplatelet commitment and patient preference.
02PREPAREPrepare for carotid stentingThe multidisciplinary team has selected elective or expedited CAS for an eligible patient.+
- 1Confirm aspirin and clopidogrel administration, allergies, adherence, bleeding history, interacting medicines and the exact last doses before entering the angiography suite.
- 2Review arch-to-intracranial imaging, select access and cerebral-protection strategy, and plan contrast load around renal and cardiac function.
- 3Record baseline cranial nerves, neurological status, pulse and blood pressure, and ensure immediate stroke and airway rescue are available.
- 4Use the centre's anticoagulation and haemodynamic protocol, with continuous rhythm and pressure monitoring during lesion crossing and deployment.
03DEFICITRespond to a new neurological deficitA focal neurological change occurs during CAS or in the monitored recovery period.+
- 1Stop nonessential procedural manipulation, establish onset and perform a rapid neurological, airway, glucose and haemodynamic assessment.
- 2Obtain urgent brain and head-and-neck vascular imaging while alerting stroke, neurointerventional and vascular teams in parallel.
- 3Differentiate intracranial embolic occlusion, stent thrombosis, dissection, hypoperfusion, hyperperfusion and haemorrhage because rescue options conflict.
- 4Deliver thrombectomy, stent rescue, antithrombotic reversal or blood-pressure treatment only through the responsible emergency team.
04AFTERCAREProtect the early post-stent periodCarotid stenting is complete and the patient enters monitored recovery.+
- 1Continue frequent neurological, rhythm and blood-pressure observations and inspect the access site for bleeding or expanding haematoma.
- 2Treat sustained hypertension, hypotension or bradycardia promptly using written unit thresholds that preserve cerebral and cardiac perfusion.
- 3Continue aspirin plus clopidogrel for at least four weeks, then transition to planned long-term antiplatelet monotherapy.
- 4Arrange duplex baseline and follow-up, risk-factor control, adherence review and clear emergency advice for recurrent neurological symptoms.
05Regimens, contraindications and interactionsTreatment details and the circumstances that modify them.
Aspirin
Give 75 to 325 mg orally once daily with clopidogrel for carotid stenting; continue the combination for at least four weeks, then follow the documented long-term single-agent plan.Check hypersensitivity, active bleeding, peptic ulcer risk and concomitant anticoagulation; prolonged dual therapy needs another indication and gastroprotection may be appropriate.
Clopidogrel
Give 75 mg orally once daily starting at least three days before CAS, or a single 300 mg oral loading dose in urgent cases; continue with aspirin for at least four weeks, then usually continue 75 mg daily alone long term.Avoid with active pathological bleeding or severe hepatic impairment; review bruising, blood counts and interacting CYP2C19 inhibitors, particularly omeprazole or esomeprazole.
06Complications, monitoring and follow-upAdverse effects, response and longer-term review.
- Perform frequent documented neurological observations after stenting and escalate any change immediately rather than attributing it to sedation.
- Monitor continuous rhythm and blood pressure around the procedure; instability during CAS warrants regular pressure monitoring for the first twenty-four hours.
- Check femoral, radial or cervical access sites for pain, swelling, haemoglobin fall, distal perfusion and concealed bleeding.
- Confirm dual antiplatelet adherence before discharge and record the minimum four-week stop or transition point unambiguously.
- Arrange a post-procedure duplex baseline and interpret later velocities against stent-specific laboratory criteria and prior studies.
- Review smoking, blood pressure, lipids, diabetes, exercise, neurological recurrence and medicine tolerance at follow-up.
07Special situationsVariants, exceptions and circumstances that change the usual approach.
Age changes procedural balance
Randomised symptomatic-trial data show an age interaction: peri-procedural stroke risk with transfemoral CAS rises in older patients, so age seventy is a practical decision boundary rather than an absolute ban.
Early timing favours CEA
When revascularisation is required in the first fourteen days after symptoms, the recurrent-stroke benefit of speed remains, but comparative procedural evidence usually favours CEA over transfemoral CAS.
Access route matters
Transradial or transcarotid access with flow reversal may avoid a hostile femoral-to-arch route, but evidence, anatomy and operator experience still govern selection.
CAS and TCAR differ
Transcarotid artery revascularisation uses direct common-carotid access and flow reversal; it should not be assumed to share every risk estimate from transfemoral CAS trials.
Cranial nerves favour stenting
Cranial nerve injury is substantially less common after CAS than CEA, which matters in a previously operated neck or when the opposite recurrent laryngeal nerve is impaired.
Low velocity can be severe
Near occlusion with distal collapse may generate low duplex velocity, so a single velocity threshold can underestimate severe anatomical disease.
08Common pitfallsFrequent interpretation and management errors.
- 01
Do not offer CAS merely because it appears less invasive; compare its embolic risk with CEA and medical therapy.
- 02
Do not transfer asymptomatic-disease thresholds or expected benefits to a recently symptomatic patient.
- 03
Do not treat age seventy as a solitary contraindication; integrate anatomy, timing, disability and audited operator results.
- 04
Do not stop dual antiplatelet treatment early after stenting without immediate specialist review of thrombosis and bleeding risks.
- 05
Do not continue aspirin plus clopidogrel indefinitely after CAS without documenting a separate indication.
- 06
Do not dismiss post-stent headache with hypertension or a seizure as routine discomfort; investigate hyperperfusion and haemorrhage.
- 07
Do not interpret surveillance velocities using native carotid criteria without a validated in-stent standard.