Carotid artery disease
D E FI N I T ION
Narrowing of the carotid artery by atherosclerosis; a common cause of
stroke.
AE T IOLOGY
Atheromatous plaque at the common carotid bifurcation or any of the
carotid branches can cause stroke or blindness by distal embolization, thrombosis or low
flow. The carotid artery bifurcation is an area of the vascular tree where atherosclerosis is
common. In combination with systemic risk factors, local haemodynamics, including low
shear stress and " turbulence affecting the outer walls opposite theflowdivider pre-dispose to
atheroma development, luminal narrowing and risk of plaque rupture, thrombosis or
embolism.
E P IDEMIOLOGY
Common, third leading cause of death in UK and major cause of longterm
disability, "incidence with age, more common in men.
H ISTORY
Often asymptomatic.
Amaurosis fugax: Transient unilateral vision loss—‘like a curtain coming down’ caused by
embolism into the ophthalmic artery (internal carotid artery branch).
Transient ischaemic attacks (TIAs): Focal symptoms lasting <24 h may be a precursor of a
stroke. (see Transient ischaemic attack).
Crescendo TIAs: TIAs that increase in duration, severity or frequency. This is associated with a
critical stenosis of the internal carotid artery, carotid dissection and may require anticoagulation
or carotid endarterectomy.
Stroke: Persistant neurological deficit (dependent on region affected by infarct). (see Stroke).
EXAMINA T I ON
If asymptomatic, often no abnormality on examination.
A carotid bruit, if present, does not reflect the degree of stenosis.
Signs of TIA or CVA (e.g. dysarthria, dysphasia, weakness in limbs).
INVE S T I G A T IONS Duplex Doppler carotid ultrasound: Non-invasive imaging to assess
degree of stenosis. There are two criteria of assessing degree of stenosis (NASCET or
ECST), and the method of evaluation needs to be noted.
CT, CTA, MRI and MRA: Brain and carotid imaging.
Angiography: Invasive (risk of precipitating stroke 1%), enables very accurate assessment
of stenosis severity.
MANAGEMENT The EXPRESS
study (Early use of eXisting PREventive Strategies for Stroke,
Lancet 2007) showed that urgent assessment and treatment reduced the 90-day risk of
recurrent stroke by 80%. All patients should be seen in a TIA clinic (urgency determined
by ABCD2 scoring).
Medical treatment: Low-dose aspirin, stopping smoking and treatment of other risk factors,
hypercholesterolaemia, hypertension and diabetes, for:
. asymptomatic stenosis,
. <70% internal carotid artery stenosis (ECST criteria),
. <50% (NASCET criteria), or
Surgical treatment: Carotid endartectomy within 2 weeks of stroke or TIA reduces risk of
further stroke in ECST and NASCET trials, although carries a significant peri-operative risk.
May be considered in:
. symptomatic stenosis of 70–99% (ECST criteria),
. symptomatic stenosis of 50–99% (NASCET criteria) or
. crescendo TIAs not responding to medical treatment.
The role of surgical treatment in asymptomatic disease is controversial.
Angioplasty þ/ stenting: Under evaluation compared to carotid endarterectomy for
symptomatic disease. The SPACE and EVA-3S trials failed to show non-inferiority of
Carotid artery disease (continued
carotid stenting vs. endarterectomy. The ICSS trial showed that carotid endarterectomy is
superior to stenting at 30-day follow-up, longer follow-up results are pending. The CREST
trial is underway but unlikely to overturn existing evidence.
COMPL I C A T IONS
Complications of disease: Stroke (thromboembolic or watershed).
Complications from surgery: Cardiac ischaemia or infarction (3%), nerve injury (2–7%,
mandibular branch of facial nerve, recurrent laryngeal nerve or hypoglossal nerves),
haematoma, peri-operative stroke (1–5%). The peri-operative mortality rate is 0.5–1.8%.
P ROGNOS I S
For carotid artery stenosis of >70%, annual stroke rate is 10–20%. If
untreated, asymptomatic stenosis of <50% has an annual stroke risk of 1%.
If surgically corrected: 6–8 fold relative risk reduction of stroke in 1 year.
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