Carotid Stenosis: Definition and Management

The carotid arteries are the main arteries supplying oxygenated blood to the brain.

When they are totally or partially obstructed, the brain is deprived of blood and this may result in ischemia or stroke.

In this article, we will discuss carotid stenosis by answering all the questions concerning its definition, its causes, its clinical manifestation as well as its therapeutic management.

Little anatomical reminder

The vasculature of the brain, face and neck is very complex. It is provided by voluminous arteries called " carotid arteries ».

These arteries take root at the level of the aorta (the largest artery which ensures the arterial supply of our body), where they take the name " common carotid arteries ou primitive ».

Born from the left heart, theaorta has an arched portion called " aortic arch which gives rise to the brachiocephalic trunk, and the latter bifurcates to form the right subclavian artery and theright common carotid artery.

La left common carotid, on the other hand, comes directly from the aortic arch.

These two arteries rise laterally at the level of the neck then form a fusiform segment about 9mm in diameter, called " carotid bulb » giving rise to two arteries: internal carotid artery et external carotid artery.

The brain is irrigated by theinternal carotid artery, while the face and the neck are vascularized by theexternal carotid artery.

Carotid stenosis: what is it?

La carotid stenosis is a vascular disease that is characterized by the narrowing or blockage of the carotid arteries. The narrowing of these arteries is defined by a diameter of the internal carotid less than 4mm or by a diameter of the common carotid less than 9mm.

The most common mechanism responsible for carotid stenosis is the formation of a atherosclerotic plaque occurring within the framework of the atheromatous disease.

Pathophysiologically, it is an obstruction of the lumen of the arteries secondary to an infiltration of their wall (intima) by fatty substances (lipids).

This phenomenon most often leads to serious complications such as stroke, especially in the presence of risk factors: age, male gender, diabetes, arterial hypertension, dyslipidemia, smoking, etc.

In addition, the stenosis can also result from a radiotherapy recurrent in the cervical region. This is generally observed in subjects treated with radiotherapy in the context of the management of a tumor of the upper aerodigestive tract.

The mechanism of stenosis in this case would be related to an acceleration of the process of formation of atheroma.

Carotid stenosis: what are the causes? 

As mentioned earlier, carotid stenosis is most often caused by atheroma. The deposit of atheroma at the arterial level is observed in people suffering from atherosclerosis, who present at least one of the risk factors mentioned above.

These risk factors contribute to the formation of atheroma by promoting aging and damage to the inner walls of the arteries.

Other causes can also be incriminated in carotid stenosis, namely:

• La fibromuscular dysplasia: rare disease affecting the intima of the arteries causing a narrowing of their caliber. This impairment can be recognized by its agiographic appearance, known as a “string of pearls”.
• THEcarotid aneurysm : corresponds to a dilation of the arterial wall leading to the formation of a sac likely to rupture over time (rupture of aneurysm).
• Le Marfan syndrome: genetic disease affecting the connective tissue of several organs including the vessels (intima of the arteries).
• THEhypercholesterolemia
• Le tabagisme and alcohol
• Heart disease
• History of stroke

How does carotid stenosis manifest?

Carotid stenosis reveals itself differently from one individual to another.

In some individuals, it may be asymptomatic, that is to say, atheroma can develop at the expense of the arteries without showing the slightest symptom.

In this case, the diagnosis is generally made by an ultrasound indicated as part of an exploration of another pathology (lucky find).

In other individuals, the stenosis is said symptomatic and typically presents with a clinical picture suggestive of a stroke.

Symptoms of carotid stenosis appear when the arterial occlusion is estimated to be more than 70% at the level of the common or internal carotids.

The clinical picture of carotid stenosis or stroke is made up of:

• Visual difficulty (transient blindness) usually unilateral
• Difficulty speaking (aphasia) ranging from difficulty in articulating to total loss of speech
• Impairment of sensitivity and motor skills of the typenumbness or paralysis, affecting part of the face or one side of the upper or lower limbs.

How to diagnose carotid stenosis?

To diagnose carotid stenosis, the doctor performs a complete physical examination and an examination of the neck in particular. Palpation and auscultation of the cervical region may reveal a carotid murmur.

In the event of the presence of a carotid murmur, this should lead to a carotid doppler ultrasound to confirm the presence of a possible carotid stenosis.

THEcarotid ultrasound is a non-invasive examination which is generally carried out within the framework of the exploration of a carotid stenosis by making it possible to visualize the carotid arteries, to highlight a possible atheroma and to quantify the degree of arterial occlusion.

In addition to the suspicion of carotid stenosis, this examination is systematically requested in people with a history of stroke or who have other atheromatous conditions such as coronary artery disease, PAD, etc.

The doctor could, if he deems it necessary, complete the exploration by carrying out a CT angiography or an carotid angio-MRI, particularly in the context of a preoperative assessment.

Carotid stenosis: what treatment?

The treatment of carotid stenosis mainly comprises three therapeutic components:

• Prevention  

It is imperative to correct all the risk factors involved in the occurrence of the atheromatous disease. It will therefore be necessary to advise patients to stop the consumption of tobacco and alcohol; treat diseases with cardiovascular risk: diabetes, hypertension et dyslipidemia.

Please note: in the event of severe carotid stenosis in a hypertensive person, the blood pressure peaks must be corrected cautiously, because a sudden drop in blood pressure could be harmful by causing cerebral ischemia by decreasing the blood pressure downstream of the stenosis.

• Medical treatment

This therapeutic aspect is essentially based on:

• The systematic initiation of a statins (hypolipidemic) for the control of hypercholesterolemia
• The prescription of an antiplatelet agent (aspirine) especially in case of symptomatic carotid stenosis (CVA). This is a blood thinner to prevent the formation of a blood clot.

• Surgical treatment

Recourse to surgery is reserved only for cases of very tight carotid stenosis or at high risk of stroke.

If the surgical indication is retained, the patient must benefit from a preoperative assessment which includes, among other things, an echo-doppler, angio-MRI or carotid angio-scan, an anesthesia consultation, a blood assessment, etc.

Technically, the surgeon (vascular surgeon) performs two types of vascular interventions:

• A endarterectomy: a very delicate technique of arterial clearing, which opens the artery and gently removes the atheroma plaque. This gesture can be supplemented by the establishment of a prosthesis (patch) to close the artery.

• A carotid angioplasty: the principle of this intervention is similar to that in coronary plasty. This involves unclogging the clogged carotid artery and placing a vascular endoprosthesis (stent) in order to prevent its re-obstruction.