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The carotid arteries are arteries that carry blood to the brain.

On each side of the neck there is a carotid artery (one on the right and one on the left), which divides into the internal and external carotid arteries. The internal carotid arteries supply blood to the brain, while the external carotid arteries supply blood to the face and skull. Therefore, the carotid arteries of interest to us are the internal carotid arteries.

Carotid stenosis is a manifestation of atherosclerosis, in which a stenosis (atherosclerotic plaque) develops at the beginning of the internal carotid artery. This stenosis can limit blood flow to the brain, although this usually does not happen because the brain receives blood from three other arteries: the contralateral internal carotid artery and two vertebral arteries. The problem is usually that clots from the surface of the atherosclerotic plaque or even small pieces of it can break off and embolize an artery in the brain, causing a stroke.

The main risk factors for carotid stenosis are:

• smoking, which increases the risk of aneurysm by about 5 times
• arterial hypertension
• hypercholesterolemia, and diabetes mellitus
• lack of physical exercise
• poor diet
• obesity

The clinical manifestations of carotid stenosis range from asymptomatic cerebral ischemia to a full-blown stroke.

The symptoms of a stroke depend on the artery that is blocked and may include:

• weakness or paralysis of one or both limbs on one side of the body
• difficulty speaking, especially when pronouncing words
• visual disturbances or blurring of one eye

Colored ultrasound (duplex) of the carotid arteries is the examination of choice for the diagnosis and assessment of the degree of carotid stenosis, while further examination with angiography (digital, magnetic or axial) is required only in cases where the results of the color ultrasound leave questions.

Conservative Treatment

Conservative treatment in patients with carotid stenosis includes antiplatelet agents, statins and management of risk factors.

According to the guidelines of the European Society of Vascular Surgery, all patients with symptomatic carotid stenosis as well as those with asymptomatic carotid stenosis >50% should receive antiplatelet therapy.

• Acetylsalicylic acid (aspirin) reduces the risk of recurrent stroke by 13-15%. The recommended daily dosage is 50-100mg.
• The combination of aspirin and dipyridamole reduces the risk of recurrent stroke by 37-38%. According to the ESPS 2 study, dual antiplatelet therapy with aspirin and dipyridamole reduces the risk of stroke by 21.3% compared with aspirin alone. Similarly, in the ESPRIT study, aspirin and dipyridamole reduced vascular death, nonfatal stroke, and nonfatal myocardial infarction by 22%.
• Clopidogrel is indicated in patients who cannot take aspirin. According to the CAPRIE study, clopidogrel reduces the risk of stroke, myocardial infarction, or death by 8.7% compared to aspirin in patients with a history of peripheral occlusive arterial disease, stroke, or myocardial infarction. Also, according to the MATCH study, the combination of aspirin and clopidogrel did not lead to a statistically significant reduction in the risk of stroke, myocardial infarction, or death in patients with a history of stroke, but increased bleeding complications. Finally, the combination of aspirin and dipyridamole was shown, in the PROFESS study, to be as effective as clopidogrel in the secondary prevention of strokes, but caused more major bleeding complications and more frequent headaches.

Statins

Patients with symptomatic carotid stenosis or asymptomatic carotid stenosis >50% should have LDL-cholesterol levels <100 mg/dL. LDL-cholesterol levels should be even lower (<70 mg/dL) for very high-risk patients.

Treatment of risk factors

• Arterial hypertension should be treated with the goal of maintaining blood pressure at levels <140/90 mmHg for non-diabetic patients with carotid stenosis and <130/80 mmHg for patients with diabetes mellitus or chronic renal failure.
• Diabetes mellitus should be treated with the aim of the patient being normoglycemic
• Smoking should be strictly stopped.
• Alcohol abuse should be avoided, as it has been found that consumption of >60 g/day of alcohol increases the risk of ischemic stroke by 70%. On the contrary, small amounts of alcohol (<24 g/day) seem to act protectively.
• Obesity should be treated, as it is associated with risk factors such as arterial hypertension, hyperlipidemia, insulin resistance and diabetes mellitus. It is also an independent risk factor for stroke, increasing the relative risk by 2 times.
• Lack of physical exercise is associated with an increased risk of stroke and, therefore, physical exercise should be recommended for all patients with carotid stenosis.

Invasive repair

Invasive repair of carotid stenosis is indicated in symptomatic carotid stenosis >50% and in asymptomatic carotid stenosis >70%. Invasive repair includes two techniques: the open surgical method (carotid endarterectomy) and the endovascular method (percutaneous angioplasty with stent placement).

In the case of carotid endarterectomy, an incision is made in the neck, the carotid artery is opened, cleaned and closed again (stapled). In the case of endovascular treatment, a balloon is inserted, usually through the femoral artery, into the area of ​​the stenosis, inflated and opened the stenosis. A metal mesh (stent) is always placed in order to keep the artery open.

Advantages of angioplasty are the avoidance of a surgical incision, the performance of the operation under local anesthesia, the neurological monitoring of the patient during the operation and the avoidance of injury to cranial nerves.

However, there is a risk that small pieces of the atherosclerotic plaque may break off and embolize arteries in the brain. To avoid this risk, various brain protection systems are used. The two most common cerebral protection systems are a filter placed distal to the stenosis to trap potential emboli, and an occlusion balloon.