Carotid artery stenosis refers to narrowing of the carotid arteries in the neck, usually secondary to atherosclerosis. Plaques build up in the carotid arteries, reducing the diameter of the lumen. There is a risk of parts of the plaque breaking away and becoming an embolus, travelling to the brain and causing an embolic stroke.
The risk factors for developing carotid artery stenosis are the same as for atherosclerosis and arterial disease in other areas, such as age, male sex, smoking, hypertension, poor diet, reduced physical activity and raised cholesterol.
Patients with a transient ischaemic attack (TIA) or stroke are investigated for carotid artery stenosis, usually with a carotid ultrasound.
Patients with carotid artery stenosis are very likely to have arterial disease and atherosclerosis elsewhere. They are at high risk of coronary artery disease and myocardial infarction (heart attacks).
Classification
The severity of carotid artery stenosis is categorised as:
- Mild – less than 50% reduction in diameter
- Moderate – 50 to 69% reduction in diameter
- Severe – 70% or more reduction in diameter
Presentation
Carotid artery stenosis is usually asymptomatic. Usually, it is diagnosed after a TIA or stroke.
A carotid bruit may be heard on examination. This is a whooshing sound heard with a stethoscope over the affected carotid artery, caused by turbulent flow around the stenotic area during systole (contraction of the heart).
Diagnosis
Carotid ultrasound is usually the initial investigation to diagnose and assess carotid artery stenosis.
CT or MRI angiogram may be used to assess the stenosis in more detail before surgical interventions.
Management
Conservative management involves addressing modifiable risk factors and medical therapy:
- Healthy diet and exercise
- Stop smoking
- Management of co-morbidities (e.g., hypertension and diabetes)
- Antiplatelet medications (e.g., aspirin, clopidogrel and ticagrelor)
- Lipid-lowering medications (e.g., atorvastatin)
Surgical interventions are considered where there is significant stenosis. The options are:
- Carotid endarterectomy
- Angioplasty and stenting
Endarterectomy involves an incision in the neck, opening the carotid artery and scraping out the plaque. This is the first-line treatment for most patients requiring surgical intervention. A key complication of the procedure is stroke (around 2%).
During endarterectomy, nearby nerves can be injured. This may be temporary or permanent. Symptoms depend on the nerve:
- Facial nerve injury causes facial weakness (often the marginal mandibular branch causing drooping of the lower lip)
- Glossopharyngeal nerve injury causes swallowing difficulties
- Recurrent laryngeal nerve (a branch of the vagus nerve) injury causes a hoarse voice
- Hypoglossal nerve injury causes unilateral tongue paralysis
Angioplasty and stenting is an alternative to endarterectomy. This is an endovascular procedure. A catheter is inserted into the femoral artery in the groin, passed through the aorta under x-ray guidance, up to the affected carotid artery. A balloon is inflated in the narrowed area to widen the lumen (angioplasty), and a stent is left in place to keep it open (stenting).
Last updated May 2021