Contents
Anatomy
The carotid arteries are two large blood vessels on the sides of the neck that carry blood, oxygen, and other important nutrients to:
- Neck
- Face
- Brain.
The common carotid artery originates from the aorta and divides at the level of the larynx into the internal and external carotid artery.
The atherosclerotic plaque almost always forms in the branching, especially in the internal carotid artery.
Pathophysiology
Blockage in these arteries may be caused by atherosclerosis, which is a progressive vascular disease characterized by the accumulation of fat, lime, fibrin, cell residue and cholesterol inside the artery.
This material:
- Forms an atheromatous plaque,
- Causes the narrowing of the artery where blood circulates.
- Hinders the delivery of oxygen and blood to the vital parts of the brain.
The narrowing of the artery leads to an increase in pressure inside.
Very often, the patient is asymptomatic or has very minor symptoms because the blood reaches the brain through various arteries.
There are two carotid arteries and two vertebral arteries, which originate from the large thoracic vessels and unite in the circulus arteriosus Willisi of the brain.
A complete blockage of the carotid artery therefore does not lead to a stroke if the other arteries are free.
However, patients often have multiple blocked arteries.
The greatest risk of carotid stenosis is the rupture of the plaque and the formation of an embolus, i.e. when a fragment tears itself loose and reaches the smallest arteries with the bloodstream.
Here it can completely occlude a blood vessel and cause a stroke.
If the blood flow is blocked for a few minutes, the brain cells begin to die.
Consequences are:
- Handicap
- Visual impairment
- speech disorders,
- Paralysis
- In the most severe cases also death.
Other factors of plaque instability include:
- The capsule surrounding the plaque has a reduced thickness,
- The internal composition of the plaques is rich in fat.
Source: The pathophysiology of acute coronary syndromes. Davies MJ Heart. 2000 Mar; 83(3):361-6.
Why do plaques tear?
Causes are:
- A very thin fibrous capsule (<50-60 microns),
- Local inflammation,
- High amount of enzymes that break down proteins [Falk E, Shah P, Fuster V. Coronary plaque disruption. Circulation. 1995;92:657–671].
A local immune response can activate macrophages, mastocytes and T-lymphocytes. These release:
- cytokines that prevent the formation of the cap,
- Proteases that digest the fibrous components of the capsule.
Source: PUBMED
Carotid stenosis mainly affects the elderly, rarely occurs in adolescents.
Causes of carotid stenosis
The most common cause of this disorder is a fatty or cholesterol plaque on the artery wall.
Risk factors:
- Hypertension
- Age
- Diabetes
- genetic predisposition,
- Smoke
- Alcohol
- Lack
- High cholesterol,
- Overweight
- Malnutrition.
Symptoms of carotid stenosis
A blockage in the carotid artery can be asymptomatic in the initial phases.
If a larger plaque build-up settles in the artery without hindering blood circulation, no symptoms occur.
The plaque can degenerate and end in ulceration.
If a person suffers a transient ischemic attack, he or she may have symptoms such as:
- weakness or inability to move arms and legs,
- Confusion
- dizziness or spinning vertigo,
- Headache
- speech disorders,
- loss of motor coordination,
- Sudden and temporary numbness of the face,
- Transient visual disturbance,
- Tingling in the arms, which can radiate to other parts of the body.
Diagnosis of carotid stenosis
The doctor orders medical examinations to determine:
- Whether the blockage is significant – i.e. covers at least 50% of the artery.
- The thickness of the tunica intima is one of the first signs of atherosclerotic disease. If the thickness of the carotid bulb is more than 2 mm (origin of the internal carotid artery), the risk of death from heart attack or stroke is greatly increased. The increase in the thickness of the intima can lead to the formation of turbulence in the blood flow.
- The consequences can then be endothelial damage and the formation of plaques.
- The speed of blood circulation. Based on this size, the probability of stenosis can be calculated. If the caliber of the artery decreases, the speed is higher. Below 125 cm/sec, it is not considered important as this corresponds to a stenosis of less than 50%. For a stenosis of 90%, the speed is between 200 and 250 cm/sec.
If there is a blockage, the blood flow causes a rough flow noise.
This is a sound or noise that the doctor hears through the stethoscope, with which he also listens to the internal body sounds.
Examinations for carotid stenosis
Echodoppler: This is a study that makes it possible to evaluate:
- The size of the plaque,
- The flow rate at the level of the narrowing,
- The plaque consistency. A young plaque is unstable and forms muscular fiber and fat cells, while a mature plaque (calcified or fibrocalcified) is stable.
In this image you can see a low-echo plaque (black).
The anechoic plaque seen on ultrasound has a low cell content and therefore consists of an accumulation of cholesterol and inflammatory cells.
It is characteristic of the initial stage of atheroma and is considered unstable because it is not yet organized (calcified).
The risk of embolism is high.
In this image you can see an echo-rich plaque (bright or white).
In this case, the plaque consists of lipids and other cells, the consistency is fibrous and has calcifications.
The lipid content is lower than in the previous image.
The plaque is more resistant and the risk of embolism is low.
In this picture you can see a calcified plaque (white).
You can see the limescale deposits.
The calcifications indicate a more mature and advanced plaque, which causes significant stenosis.
Behind the calcification, shading (black area) can be seen because the tissues that are behind the calcification are hidden.
This plaque is much less dangerous.
With complete calcification, the plaque is stable and there is no risk of embolism.
Angiography
In the cerebral angiogram, a contrast agent is injected into the carotids, after which an X-ray is taken.
The contrast agent passes through the arteries with the blood flow.
In this way, the extent and localization of the blockade are shown.
Nowadays, it is replaced by angio-CT for diagnosis, while it is still used during surgery.
Angio-CT – is the most common form of examination after the echo Doppler.
It consists of injecting a contrast agent followed by a CT scan to examine the blood vessels.
The examination is very reliable, although the calcified plaques are often not displayed correctly.
It can be performed simultaneously with brain CT to assess the presence of possible embolisms.
This examination serves to clarify whether the operation is indicated.
Angio-CT is performed non-invasively.
Computed tomography (CT): This examination shows possible brain damage caused by a stroke.
MR angio: This is a non-invasive examination, but it is contraindicated in patients with a pacemaker. It can overestimate stenosis.
Method for determining percentage narrowing
A = diameter of the artery in which the blood flows at the level of the plaque.
B = diameter of the internal carotid artery without plaque
C = total diameter of the carotid sinus (at the level of the branching of the internal and external carotid artery)
D = diameter of the common carotid artery (before branching)
- NASCET method = (B – A)/B * 100
- ECST method = (C – A)/C * 100
- Carotid communis method = (D – A)/D * 100
The NASCET method has lower values, for example, a closure of 70% in ECST becomes about 50% in the NASCET method.
Treatment of carotid stenosis
Treatment of carotid stenosis depends on several factors:
- Age
- State of health
- Anamnesis of the patient.
Diagnostic signs such as plaque size, whether the patient is operable or not, and the medications affect the course of treatment. There are three ways in which a narrowing of the carotid artery can be treated:
- Medication
- lifestyle changes,
- Surgery.
Medication for carotid stenosis
If the accumulation of plaques in the arteries is less than 60%, the doctor may prescribe some medications to delay clot formation in the arteries.
Anticoagulant drugs such as clopidogrel (Plavix) and dipyridamole (Aggrenox) delay the formation of blood clots.
These drugs decrease the ability of platelets to stick together to form thrombi in the arteries.
The doctor may also prescribe anticoagulants for the same purpose.
With elevated blood pressure, drugs for arterial hypertension are taken, which keep blood pressure under control.
For hypercholesterolemia and hyperlipidemia, the doctor may prescribe drugs called statins, such as pravastatin and simvastatin.
Statins can reduce plaque formation and thus expand vascular volume.
Natural remedies for carotid stenosis
To keep the size of the plaques limited, one should stop smoking and consume fewer ready meals.
According to the blood group diet, the cause of plaque formation is a diet that includes milk and dairy products (yogurt, cheese, etc.).
Therefore, the most appropriate natural treatment is the removal of such foods from the diet.
You should keep your body weight in shape with a diet and exercise regularly.
To prevent stroke, arterial blood pressure and blood sugar levels must be kept normal.
Guidelines for surgical intervention: when to operate on carotid stenosis?
Patient with symptoms
| Percentages of internal carotid stenosis | Recommendations |
| 70/99% | Surgery in patients with narrow stenosis is indicated for those patients who have had symptoms in the last 6 months. |
| 50/69% |
|
| < 50% | Surgery is not recommended for moderate stenosis, i.e. with a closure of less than 50%. |
Asymptomatic patient
A patient with a closure between 60 and 99% must expect surgery if he is operable and if he has a life expectancy of more than 5 years (because the results can only be seen after a few years).
Source: American Academy of Neurology
Angioplasty with stent in the carotid
This procedure is performed in patients who have contraindications to traditional surgery.
Carotid angioplasty with stent insertion is a minimal invasion.
It is performed by means of a catheter, which is guided from the groin to the carotid. Once this plastic tube has reached the plaque, a balloon is inflated to widen the artery, after which a stent is positioned.
The stent consists of a metal mesh in the form of a cylinder, which keeps the artery open and provides it with the necessary support.
One of the complications of this process is the risk of embolism, because when the balloon is inflated, fragments can break loose, exiting through the stent and reaching the brain.
There are two protection systems for this:
- The surgeon inserts a filter above the plaque level to stop the clots,
- Insertion of balloons that stop blood circulation.
Stent risks in carotid stenosis
About 1-2% of people with a stent in an artery develop a blood clot inside this structure.
A blood clot can lead to a thrombus or embolus and cause a myocardial infarction or other serious problems.
The risk of forming a blood clot is greater in the first months after insertion of the stent.
The doctor will prescribe aspirin along with another anticoagulant drug (for example, clopidogrel) for a month or up to about a year.
These drugs prevent the formation of thrombi.
The duration of drug therapy depends on the type of stent.
The doctor may order long-term medication with aspirin.
The stents, which contain a medicine, are often used to keep arteries open, but they can also increase the risk of potentially dangerous thrombi, even if there is no reliable evidence of this.
Surgery of endarterectomy
Plaque removal surgery can be performed under local anesthesia.
The surgeon makes a 3-5 cm incision at the front of the neck and opens the artery.
After that, he must clamp the carotid artery above and below the plaque.
Once the artery is opened, the surgeon removes the atherosclerotic plaque and also decides whether the artery will be widened if it is too narrow.
Finally, he closes the artery with an extension patch.
Then he removes the “staples” and lets the blood flow through again.
The duration of the procedure is about one and a half to two hours.
Variants:
- CEA with revision and reimplantation technique: The carotid interna is completely prepared and rotated, then the plaque is removed and the vessel is reinserted.
- CEA with bypass: consists of excluding the affected carotid segment by a prosthesis or graft from a vein.
Postoperative course of carotid stenosis
The surgeon inserts a tube for drainage and applies an infusion.
After the procedure, an angiography must be performed for control.
The day after the procedure, the patient can be discharged home.
The patient feels pain when swallowing, so soft foods should be consumed.
How long does recovery take?
Convalescence lasts about two weeks, during which efforts should be avoided
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