Symptomatic Carotid Stenosis

1 · UNDERSTAND — What is happening?

Definition

Symptomatic carotid stenosis means an ipsilateral carotid-territory event within the previous 6 months: amaurosis fugax, TIA or non-disabling ischaemic stroke, associated with a 50–99% internal carotid artery stenosis measured by the NASCET method.

Non-focal symptoms such as dizziness, syncope or bilateral visual blurring do not make a stenosis symptomatic.

Anatomy and mechanism

Disease is usually centred on the carotid bifurcation and proximal internal carotid artery. The mechanism is mainly artery-to-artery thromboembolism from an unstable plaque, not simple flow limitation. Plaque activity and recurrent stroke risk are highest soon after the neurological event, which is why benefit from surgery falls sharply with delay.

Presentation

• Amaurosis fugax: transient monocular visual loss, classically described as a curtain.
• Hemispheric TIA or minor stroke: contralateral face/arm/leg weakness or numbness, dysphasia in dominant hemisphere events, or neglect.

Important differentials include atrial fibrillation, lacunar stroke, carotid dissection, carotid web, intracranial stenosis and stroke mimics such as hypoglycaemia, migraine and seizure.

Investigations

1. Brain imaging: CT or MRI to exclude haemorrhage and define infarct size before dual antiplatelet therapy or intervention.
2. Duplex ultrasound: first-line carotid test. UK joint criteria use ICA PSV above 1.25 m/s with PSV ratio above 2 for ≥50%, and PSV above 2.3 m/s with ratio above 4 for ≥70%.
3. CTA or MRA: confirm stenosis severity and define lesion height, distal extent, calcification, near-occlusion, arch/access anatomy, tandem disease and intracranial disease.
4. Cardiovascular work-up: ECG ± rhythm monitoring for AF, lipids, HbA1c and blood pressure.

NICE expects carotid imaging reports to state whether NASCET or ECST measurement was used. UK stroke guidance expects NASCET reporting and carotid imaging within 24 hours of specialist assessment for candidates for intervention. Do not use ABCD2 to downgrade urgency after suspected TIA or minor stroke.

Classification

• NASCET: denominator is normal distal ICA; standard in UK/ESVS practice.
• ECST: denominator is estimated original bulb diameter; produces higher percentages for the same lesion.
• Practical bands: under 50%, 50–69%, 70–99%, near-occlusion with distal ICA collapse, and complete occlusion.

2 · DECIDE — What do I do next?

Decision algorithm

1. TIA / non-disabling stroke / amaurosis fugax: give aspirin 300 mg immediately, exclude haemorrhage/infarct burden with brain imaging, and complete urgent specialist assessment.
2. Confirm the culprit lesion: ipsilateral carotid stenosis should be reported using the NASCET method; use duplex first-line and confirm with CTA or MRA if intervention is possible.
3. Under 50% stenosis or complete occlusion: best medical therapy only.
4. Near-occlusion with distal collapse: best medical therapy; consider intervention only selectively for recurrent symptoms despite best medical therapy after MDT review.
5. 50–99% stenosis: check neurological suitability. Defer intervention if there is disabling stroke, mRS ≥3, infarct over one third of the MCA territory, or reduced consciousness.
6. After IV thrombolysis: consider delaying carotid intervention by about 6 days if clinically safe.
7. If suitable for intervention: list for CEA as soon as safe. UK vascular audit/NVR uses symptom-to-CEA within 14 days; the National Clinical Guideline for Stroke for the UK and Ireland recommends within 7 days; ESVS recommends as soon as possible, preferably within 14 days.
8. Choose CEA vs CAS: CEA is preferred in the first 14 days and in patients aged ≥70. In selected patients under 70, CAS may be considered if audited stroke/death risk is below 6%.

Core decision

Start best medical therapy immediately, confirm symptom attribution and stenosis severity, then decide whether the patient is suitable for expedited carotid endarterectomy.

1. TIA / non-disabling stroke / amaurosis fugax: aspirin 300 mg immediately and urgent specialist assessment.
2. Brain imaging + carotid duplex: confirm with CTA or MRA if intervention is possible.
3. Under 50% stenosis or occlusion: best medical therapy only.
4. Near-occlusion with distal collapse: best medical therapy; intervention only selectively, usually for recurrent symptoms despite best medical therapy after MDT review.
5. 50–99% stenosis with suitable neurology: expedited CEA, unless deferral criteria apply.

Decision modifiers

• 70–99%: CEA is recommended if documented 30-day stroke/death risk is below 6%.
• 50–69%: CEA should be considered if documented 30-day stroke/death risk is below 6%; benefit is smaller and more selective.
• Timing: operate as soon as safe. UK vascular audit/NVR uses symptom-to-CEA within 14 days. The National Clinical Guideline for Stroke for the UK and Ireland recommends within 7 days. ESVS recommends as soon as possible, preferably within 14 days.
• Within 14 days of symptoms: CEA is preferred over transfemoral CAS.
• Age ≥70: CEA rather than CAS.
• Age under 70: CAS may be considered as an alternative in selected patients if audited stroke/death risk is below 6%.
• Disabling stroke, mRS ≥3, infarct over one third MCA territory or reduced consciousness: defer carotid intervention to reduce haemorrhagic transformation risk.
• After IV thrombolysis: defer carotid intervention by about 6 days if clinically safe.

Special situations

• Free-floating thrombus: therapeutic anticoagulation; consider surgical or endovascular removal only if recurrent symptoms occur despite anticoagulation.
• AF plus ipsilateral 50–99% stenosis: complete neurovascular work-up and MDT discussion to decide urgent revascularisation vs anticoagulation alone.
• Crescendo TIA or stroke-in-evolution: urgent CEA may be considered, preferably within 24 hours, if imaging and clinical features are suitable.

Practice divergence

Use 14 days as the familiar UK vascular audit/NVR and ESVS target. Mention the 7-day target specifically as the National Clinical Guideline for Stroke for the UK and Ireland ambition. Avoid presenting “UK = 7 days” without this nuance.

3 · JUSTIFY — Why is that the correct decision?

Why operate at all?

The mechanism is unstable embolic plaque with front-loaded recurrence risk. Removing the source early prevents stroke, but only when stenosis severity, symptom attribution, neurological status and procedural risk are appropriate.

• NASCET 1991: symptomatic 70–99% stenosis; 2-year ipsilateral stroke fell from 26% to 9% with CEA.
• NASCET 1998: symptomatic 50–69%; 5-year ipsilateral stroke fell from 22.2% to 15.7%, NNT 15. Under 50% did not significantly benefit.
• ECST 1998: confirmed severe symptomatic benefit, but used ECST measurement; surgical major stroke/death 7.0%.
• Pooled analysis 2003: 5-year ARR 16.0% for ≥70% without near-occlusion; 4.6% for 50–69%; no useful benefit below 50%; near-occlusion uncertain.
• Rothwell timing analysis 2004: NNT 5 if treated within 2 weeks vs 125 after more than 12 weeks.

Why CEA over stenting?

• CREST: mixed symptomatic/asymptomatic trial; symptomatic peri-procedural stroke/death was 6.0% with CAS vs 3.2% with CEA in symptomatic-status analysis.
• ICSS: symptomatic trial; 120-day stroke/death/procedural MI 8.5% with CAS vs 5.2% with CEA; cranial nerve palsy was lower after CAS.
• ICSS long-term: 5-year fatal/disabling stroke was similar, but any stroke was higher after CAS.
• CSTC pooled age analysis: CAS risk rises with age; CAS vs CEA procedural stroke/death HR was 2.09 at age 70–74.

Modern medical therapy context

ECST-2 reported no 2-year benefit from adding revascularisation to optimal medical therapy in asymptomatic or low/intermediate-risk symptomatic ≥50% stenosis. This should not override classic urgent CEA evidence for high-risk symptomatic 70–99% disease, but it should stop automatic intervention in low-risk or uncertain cases.

Medical therapy

• Do not let antiplatelet uncertainty delay expedited CEA.
• Minor stroke/high-risk TIA evidence supports early aspirin plus clopidogrel, with benefit concentrated in the first 10–21 days.
• ESVS recommends local protocols between stroke physicians and vascular surgeons to define monotherapy vs combination therapy around CEA.
• Peri-operative combination antiplatelet therapy should be considered after imaging excludes intracranial haemorrhage.
• Use lipid-lowering therapy: statin, ezetimibe if targets are not reached, and consider PCSK9 inhibitor if still not at target or statin-intolerant.

Anaesthesia and closure

• GALA: general vs local anaesthesia had similar stroke/MI/death outcomes; choose individually.
• Patch closure: Cochrane evidence supports patching over primary closure for lower occlusion, restenosis and peri-operative ipsilateral stroke, though certainty is low to very low.

4 · PERFORM — How do I execute the plan?

Execution

1. Now: aspirin 300 mg immediately, urgent specialist assessment, haemorrhage exclusion, antiplatelet strategy per local carotid/stroke protocol, high-intensity statin, BP optimisation and smoking cessation.
2. Imaging: duplex at assessment, then CTA or MRA to confirm degree, lesion anatomy, near-occlusion, arch/access anatomy and intracranial disease.
3. MDT: confirm symptom attribution, side, degree, cardiac embolic sources and deferral criteria.
4. List for CEA as soon as safe: meet the UK vascular audit/NVR 14-day target and aim for the National Stroke Guideline 7-day target where pathway capacity allows.
5. Pre-operative assessment: cardiac risk assessment should not delay surgery; plan local vs general anaesthesia with the anaesthetist and patient.
6. Consent: quote the unit's audited NVR stroke/death figure; benchmark should be below 6%. Discuss cranial nerve injury, neck haematoma, MI, hyperperfusion syndrome, restenosis and patch infection.

Procedure links: Carotid Endarterectomy Procedure Guide; Carotid Artery Stenting & TCAR Procedure Guide.

5 · MANAGE — What can go wrong and how do I respond?

Complications and actions

• New neurological deficit: think thrombosis, embolus or intimal flap. If deficit develops after clamp release under local anaesthesia, ESVS recommends immediate re-exploration of the carotid artery.
• Neck haematoma: swelling, stridor or airway compromise. Airway first; open the wound at bedside if needed, then return to theatre.
• Cranial nerve injury: tongue deviation, hoarseness, dysphagia or marginal mandibular weakness. Most are transient; check vocal cords before contralateral CEA if there is concern.
• Hyperperfusion syndrome: ipsilateral headache, seizures, confusion or intracerebral haemorrhage. Treat with strict BP control, urgent brain imaging and seizure management.
• Haemodynamic instability: carotid sinus manipulation may cause bradycardia, hypotension or hypertension; monitor and treat with vasoactive drugs as needed.
• MI: ECG and troponin if symptomatic or clinically concerned; involve cardiology.
• Patch or stent infection: rare but serious; ESVS recommends excision and autologous venous reconstruction rather than prosthetic reconstruction.
• Restenosis: if symptomatic 50–99% re-stenosis, redo CEA or CAS is recommended. If symptomatic <50% restenosis, medical therapy is recommended. Asymptomatic 70–99% restenosis after CEA may be considered for re-intervention after MDT review.

Long-term follow-up

Continue lifelong best medical therapy. Duplex surveillance is not routine for every CEA/CAS patient; use it selectively in patients at higher risk of restenosis and in high-risk haemodynamic or monitoring subgroups identified by ESVS.

6 · REMEMBER — What must I retrieve instantly?

If you remember only 10 things

1. Symptomatic = ipsilateral carotid-territory event within 6 months.
2. Measure stenosis by NASCET; ECST gives higher percentages for the same lesion.
3. 70–99% symptomatic stenosis: CEA is recommended if procedural stroke/death risk is below 6%.
4. 50–69%: CEA should be considered, but benefit is smaller and selective.
5. Under 50% or occlusion: best medical therapy, not carotid intervention.
6. Speed is the benefit: NNT 5 within 2 weeks vs 125 after 12 weeks.
7. Timing language: UK vascular audit/NVR 14 days; National Stroke Guideline 7 days; ESVS preferably 14 days.
8. CEA beats CAS in the first 14 days and at age ≥70.
9. Aspirin 300 mg now; dual antiplatelet strategy after haemorrhage exclusion according to local protocol; statin ± ezetimibe.
10. GALA: local and general anaesthesia similar. Patch closure is favoured over primary closure.

Key numbers

• 6 months: symptomatic window.
• 24 hours: urgent specialist assessment/imaging pathway.
• 7 / 14 days: National Stroke Guideline 7-day target; UK vascular audit/NVR and ESVS 14-day target.
• 6%: maximum acceptable procedural stroke/death risk for symptomatic carotid intervention.
• About 6 days: defer carotid intervention after IV thrombolysis if clinically safe.
• 1.25 / 2.3 m/s: ICA PSV thresholds for ≥50% / ≥70% on UK joint duplex criteria.

FRCS prompts

• 72-year-old, left hemispheric TIA 3 days ago, 80% left ICA: confirm with CTA, start medical therapy, exclude deferral criteria, expedite CEA, not CAS.
• Why not stent? Higher early stroke/death with CAS in symptomatic patients; risk rises with age.
• Thrombolysed yesterday: defer about 6 days if safe, treat medically meanwhile.
• New deficit after clamp release under local anaesthesia: immediate re-exploration.
• Trap: 50–69% stenosis in a woman with non-hemispheric symptoms months ago: benefit may be minimal or absent.

Memory hook: Six months, fifty per cent, fourteen days — and know the seven-day stroke-guideline target.

1. Naylor R, Rantner B, Ancetti S, et al. ESVS 2023 Clinical Practice Guidelines on the Management of Atherosclerotic Carotid and Vertebral Artery Disease. Eur J Vasc Endovasc Surg. 2023;65(1):7-111. doi:10.1016/j.ejvs.2022.04.011.
2. NICE. Stroke and transient ischaemic attack in over 16s: diagnosis and initial management. NG128. 2019, updated 2022.
3. Intercollegiate Stroke Working Party. National Clinical Guideline for Stroke for the UK and Ireland. 2023.
4. Bonati LH, Kakkos S, Berkefeld J, et al. European Stroke Organisation guideline on endarterectomy and stenting for carotid artery stenosis. Eur Stroke J. 2021;6(2):I-XLVII.
5. AbuRahma AF, Avgerinos ED, Chang RW, et al. SVS clinical practice guidelines for extracranial cerebrovascular disease. J Vasc Surg. 2022;75(1S):4S-22S. doi:10.1016/j.jvs.2021.04.073.
6. NASCET Collaborators. Beneficial effect of carotid endarterectomy in symptomatic patients with high-grade carotid stenosis. N Engl J Med. 1991;325:445-453.
7. Barnett HJ, Taylor DW, Eliasziw M, et al. Benefit of carotid endarterectomy in symptomatic moderate or severe stenosis. N Engl J Med. 1998;339:1415-1425.
8. European Carotid Surgery Trialists' Collaborative Group. Randomised trial of endarterectomy for recently symptomatic carotid stenosis: final ECST results. Lancet. 1998;351:1379-1387.
9. Rothwell PM, Eliasziw M, Gutnikov SA, et al. Analysis of pooled data from randomised trials of endarterectomy for symptomatic carotid stenosis. Lancet. 2003;361:107-116.
10. Rothwell PM, Eliasziw M, Gutnikov SA, et al. Endarterectomy for symptomatic carotid stenosis in relation to clinical subgroups and timing. Lancet. 2004;363:915-924.
11. Brott TG, Hobson RW, Howard G, et al. Stenting versus endarterectomy for carotid-artery stenosis. N Engl J Med. 2010;363:11-23.
12. Ederle J, Dobson J, Featherstone RL, et al. ICSS interim analysis. Lancet. 2010;375:985-997.
13. Bonati LH, Dobson J, Featherstone RL, et al. ICSS long-term outcomes. Lancet. 2015;385:529-538.
14. Howard G, Roubin GS, Jansen O, et al. Age and stroke/death risk from CEA and CAS. Lancet. 2016;387:1305-1311.
15. GALA Trial Collaborative Group. General vs local anaesthesia for carotid surgery. Lancet. 2008;372:2132-2142.
16. Strömberg S, Gelin J, Osterberg T, et al. Very urgent carotid endarterectomy. Stroke. 2012;43:1331-1335.
17. Coelho A, Peixoto J, Mansilha A, Naylor AR, de Borst GJ. Timing of carotid intervention: systematic review and meta-analysis. Eur J Vasc Endovasc Surg. 2022;63:3-23.
18. Kakkos SK, Vega de Ceniga M, Naylor R. Carotid interventions following thrombolysis. Eur J Vasc Endovasc Surg. 2021;62:340-349.
19. Hao Q, Tampi M, O'Donnell M, et al. Clopidogrel plus aspirin vs aspirin alone after minor stroke/high-risk TIA. BMJ. 2018;363:k5108.
20. Orrapin S, Benyakorn T, Siribumrungwong B, Rerkasem K. Patch angioplasty vs primary closure for CEA. Cochrane Database Syst Rev. 2022;8:CD000160.
21. Oates CP, Naylor AR, Hartshorne T, et al. UK carotid ultrasound reporting recommendations. Eur J Vasc Endovasc Surg. 2009;37:251-261.
22. Donners SJA, van Velzen TJ, Cheng SF, et al. ECST-2 interim results. Lancet Neurol. 2025;24:389-399.
23. Silver FL, Mackey A, Clark WM, et al. CREST symptomatic-status analysis. Stroke. 2011;42:675-680.