Occlusion of the internal carotid artery prognosis. Symptoms and treatment of blockage of the carotid artery

Blockage carotid artery, also called carotid stenosis, is a decrease in inner surface carotid artery due to the formation of atherosclerotic plaque. In other words, a blockage in the carotid artery is the result of blockage of a blood vessel in the neck due to the formation of plaque on its walls.

Carotid arteries are two large blood vessels running on each side of the neck that carry blood, oxygen, and important nutrients to the brain. They branch off from the aorta and rise up along the neck. It is through the carotid arteries that you can feel the pulse on each side of the neck. The blockage of these arteries provokes atherosclerosis, a progressive vascular disease characterized by the formation of atherosclerotic plaques on the inner walls of the arteries, consisting of fatty substances, calcium, fibrin, cellular debris and cholesterol. This disease causes narrowing of the arteries and causes a condition known as carotid disease.

Risks of blocked carotid artery

It should be noted that blockage of the carotid artery is one of the main factors contributing to stroke. This is due to the fact that over time, when the plaque hardens and finally narrows the artery, the flow of blood and oxygen to the brain is limited. Without the proper amount of blood and oxygen, brain cells begin to die. This results in loss of function and permanent brain damage or death of the patient.

In certain cases, the formed plaque can break away from the wall of the artery, move through the bloodstream and get stuck in one of the vessels of the brain. This can provoke a transient ischemic attack. In this regard, it is very important to monitor the appearance of symptoms of blockage of the carotid artery in order to take all necessary measures before the patient's condition begins to worsen.

Common Symptoms

On the initial stages blockage of the carotid artery may not be accompanied by the appearance of any symptoms. If there is a significant accumulation of plaque in the artery, but they do not significantly affect the blood flow, there are usually no symptoms either. However, gradual increase plaque accumulation can lead to complete blockage of blood flow and cause a transient ischemic attack or cerebral stroke.

In the case of a transient ischemic attack, the following symptoms may occur:

• Weakness or inability to move your arms and legs
• Confusion and dizziness
• Headaches
• Fainting
• Difficult, slurred speech
• Loss of motor coordination
• Sudden and temporary numbness in the face
• Temporary loss of vision
• Difficulty swallowing
• A tingling sensation in the hands that radiates to other parts of the body

If a person suffers a stroke, in addition to these symptoms, he may also experience a loss of other vital body functions, such as memory and thinking, food intake, work Bladder and control of emotions.

Diagnostics

If any of the above symptoms occur, seek medical attention immediately medical care. Unless there is a stroke or paralysis, most doctors rely on checking the pulse with a stethoscope to detect any unusual sounds that occur as the blood overcomes the obstruction. Once the blockage has been located, a duplex is performed to locate the blockage and determine the amount of blood passing through the artery. ultrasound procedure. To determine the degree of stenosis, another one is used diagnostic test known as cerebral angiography. A special contrast agent (usually blue or black) is injected into the artery, after which an x-ray is taken. The results of this study show, thanks to the contrast agent, the exact location and size of the blockage.

For stroke or paralysis, doctors may do tests such as CT, carotid duplex scanning, transcranial Doppler, MRI, magnetic resonance angiography, xenon-enhanced CT, radionuclide gamma tomography, cerebral angiography, and positron emission tomography and transesophageal echocardiography.

How is a blocked carotid artery treated?

Treatment for carotid artery blockage depends on various factors, including age, health, and medical history patient. Usually, the course of treatment is determined by the signs and symptoms present, the degree of stenosis, and the tolerance of various surgical procedures and drugs, for example normapulsa.org In general, the treatment of blockage of the carotid artery can be carried out in three main areas - medication, lifestyle changes, and surgery.

Lifestyle change

In addition to age and a family history of carotid artery blockage, risk factors for this condition include increased blood pressure, high blood cholesterol and diabetes. Smoking, a diet high in saturated fats, a sedentary lifestyle, and obesity can further aggravate the condition. To control the formation of atherosclerotic plaques, you should stop smoking and eat food with low content saturated fats and trans fats. It is important to support normal weight by eating a healthy diet and exercising regularly. Also, to effectively reduce the likelihood of a stroke, it is necessary to control blood pressure and diabetes.

Taking medications

If the artery is less than 60% blocked by plaque, certain drugs may be prescribed to prevent blood clots in the artery. Antiplatelet agents such as clopidogrel and dipyridamole are often used. These drugs reduce the ability of platelets to stick together and form blood clots in the arteries. Anticoagulant drugs, or blood thinners, are also used to reduce the risk of blood clots.

If you have high blood pressure, you may be recommended to control it. antihypertensive drugs. With an increased amount of fat in the blood, antihyperlipidemic drugs such as pravastatin and simvastatin are used. It is known that these drugs reduce the thickness of the walls of the arteries and increase their lumen.

Surgical treatments

If atherosclerotic plaques clog the artery by 70 percent or more, or if the patient has already had a microstroke, consider surgical methods treatment. For blockages between 50% and 69%, doctors may recommend surgery based on the patient's age and health status.

Carotid angioplasty with stenting

A newer procedure than endarterectomy for the treatment of carotid artery blockage is carotid angioplasty with stenting. A minimally invasive procedure, it involves inserting a catheter into the carotid artery through a blood vessel in the groin. Once the catheter is in place, a small balloon is inflated into the artery to open it up, and a stent is placed at the site of the blockage. A stent is a miniature wire mesh that keeps an artery open. In order to prevent the movement of plaque particles during the procedure to other parts of the body, the surgeon uses an embolic filter that captures them.

Endarterectomy

This is the standard surgical procedure used to treat blockage of the carotid artery, in which fatty plaques in it are removed through an incision in the neck. After gaining access to the artery by cutting tissue, the surgeon occludes the artery and opens it longitudinally. He then physically removes the plaque with scraping, and finally widens the artery with a diamond-shaped flap and sutures it.

So, in order to prevent a deadly stroke or paralysis, it is necessary to watch for the appearance of symptoms of blockage of the carotid artery and promptly carry out appropriate treatment. To avoid blockage of the carotid artery, it is important to take care of your health and keep fit. Avoiding alcohol and tobacco, eating a low-fat and low-cholesterol diet, and exercising regularly can greatly help prevent this disease.

As you know, these vessels pass throughout our body. Therefore, when making a diagnosis, the localization of the lumen is always specified - carotid, superficial femoral or other artery, left or right.

Stenosis and occlusion are closely related concepts. It should be noted that occlusion can act as a surgical intervention, which is reflected in the names of some operations. An example is X-ray endovascular occlusion of atrial septal defect (ASD), endovascular type of occlusion, and others. All this requires careful consideration, starting from the causes and types of vascular obstruction.

Causes

Stenosis and occlusion of vessels develop according to certain reasons, the main of which is embolism. This is the name of the blockage of the lumen by a dense formation in the bloodstream, which occurs due to factors, mainly of an infectious nature. There are several types:

1. Air embolism. An air bubble enters the vessels as a result of pulmonary damage, improper injection.
2. arterial embolism. The vessel, vein or artery is clogged with mobile blood clots, which are formed in the pathology of the valvular heart apparatus.
3. Fat embolism. As a result of metabolic disorders, and sometimes trauma, tiny fatty particles accumulate in the blood and stick together into one large clot.

A favorable condition for the development of embolism, and as a result - occlusion, is thrombosis. This is a gradual narrowing of the arterial lumen due to a constant increase in the number and size of blood clots on the inner walls.

To varying degrees, the prerequisite for arterial obstruction is also atherosclerosis of the vessels, which can develop, that is, move from one degree to another.

Injury, when the muscle or bone, can lead to compression of large blood vessels which slows down blood flow. Where the artery is occluded, thrombotic processes can begin.

There are several types of occlusions:

1. Thrombosis. Clotting of the blood flow by thrombi is usually observed in the veins of the lower extremities. It has been noted that only a third of patients with such a disease are subject to diagnosis and treatment, since in others it occurs without obvious symptoms or even their absence.
2. Obstruction of the subclavian artery. The defeat of one of the most important vessels leads to the development of vascular brain failure, upper limb ischemia. According to various sources, blockage of the first segment of the subclavian artery is found in the range from 3 to 20%. In this case, very often there are concomitant lesions of the vertebral or second segment of the subclavian arteries. In such cases, immediate treatment is required.
3. Thrombotic and post-thrombotic occlusion. The latter is closely related to post-thrombotic disease, the pathogenesis of which is rather complicated. The factors that determine the process of thrombus recanalization have not been studied so far.
4. Acute occlusion. This is the result of a sudden cessation of blood flow, which leads to additional formation of blood clots. The condition is characterized by a severe course, but is not irreversible if help is provided from the very beginning within four hours. Deep ischemia leads to irreparable necrotic complications.
5. Retinal vein occlusion depending on the individual eye. This is a violation of blood circulation in the central retinal vein or its branches. Observed with age.
6. Occlusion of the BPS, that is, the femoral-popliteal segment. Blood that is enriched with oxygen does not flow to the lower leg, and this is accompanied by certain signs. The cause is usually atherosclerosis obliterans.

There are other types of occlusion of the left and right artery depending on localization. In any case, they threaten human health and can lead to irreversible changes in the body. If symptoms are present and special surveys, it is not difficult to diagnose and identify different degrees of the disease.

Early stages of subclavian artery obstruction are treated conservative way, complications require often surgical intervention. It is important to consider that treatment begins only after the discovery of the cause of the disease. Removing symptoms is not enough.

Of course, we must not forget that arterial obstruction can be caused on purpose when it is part of an operative intervention. These are ASD occlusion, and endovascular occlusion, and partial occlusion when the lower half of the glass of the leading eye is turned off.

Symptoms

Symptoms of BPS, that is, the femoral artery:

• cold feet;
• pallor skin lower limbs;
• intermittent claudication - numbness and pain in the calf muscles.

In thrombotic occlusion, the clinical picture is based on one or more of the following:

Obstruction of the vertebral artery is characterized similarly. The medical literature describes several main symptoms in the blockage of any vessel. In the neck and head, they appear especially quickly:

1. Pain is the first symptom. Present in the affected area, gradually increasing, may disappear if the thrombus advances on its own, even without treatment.
2. No pulse. It is often difficult to determine, since you need to check exactly the specific place where the blood flow is disturbed in the vein.
3. Paleness of the skin, for example, in the face, and subsequent cyanosis. When there is no necessary nutrition for a very long time, signs such as dryness, peeling, wrinkles appear.
4. Paresthesia. It manifests itself when a person complains of tingling, numbness, goosebumps, then tactile sensitivity joins. With the duration of the condition, paralysis may develop.

Occlusion of the internal carotid artery (ICA) is most often expressed as a transient ischemic attack. The most typical symptoms are mono- or hemiparesis, sensory disturbances on the opposite, left or right side. There are monocular visual disturbances on the affected side.

Diagnostics

Any form of obstruction of the veins and arteries requires a thorough diagnosis: the prompt detection of symptoms and the appointment of specific studies.

These activities are carried out only in a hospital setting. Occlusion of the ICA, subclavian artery, post-thrombotic obstruction of the left or right vein, and any other similar pathology is detected using various research methods: general analysis blood, cholesterol analysis, coagulograms, ECG, EEG, REG of head and neck vessels, MRI, CT, dopplerography of the neck.

The treatment of occlusion depends on the exact diagnosis. In an acute case, thrombectomy is performed. If the periprocess is expressed, phlebolysis is done. Anticoagulant therapy is very important. Secondary forms of the syndrome are the result of compression of the vein by lymph nodes, tumors.

Therapy is carried out depending on the cause that caused the violation of the outflow venous blood. A thorough diagnosis is necessary in violation of the obstruction of the subclavian artery, and this is possible only in the appropriate clinic.

With occlusion of the femoral artery, the body is able to compensate for the circulation of the limb with the help of blood flow along the lateral branches of the arterial system. Then conservative treatment can be successful. If ischemic symptoms become more pronounced, and intermittent claudication appears after a hundred meters of walking or less, surgical intervention will be required. This may be an endarterectomy, femoral popliteal or femoral tibial bypass.

It has been mentioned that occlusion acts as an operation. For example, there is a temporary transvaginal obstruction of the uterine arteries: they block the blood flow for a specific time during which healthy uterine tissue finds nutrition, and myomatous nodes die due to the lack of an extensive vascular nutritional network. No incisions are made during this procedure. Through the vagina under anesthesia on uterine arteries clips are applied for six hours. After their removal, blood flow is restored only in the uterus, but not in the myoma nodes.

Occlusion of an ASD, a method of transcatheter closure of an abnormal orifice using a special system - an occluder, helps to close holes no more than two centimeters. This is one of the ways to treat ASD, the disease cannot be treated on its own.

Direct occlusion is the exclusion from the act of seeing the eye that sees better. This is a very common treatment for amblyopia. To develop binocular vision, a certain visual acuity of the worst eye is required, namely not less than 0.2. The procedure takes two to six months. Once a week, the vision of two eyes is monitored, since it may decrease for a while with the eye turned off. This method does not always give a positive result.

With regard to vision, we can say that there are such concepts as permanent and intermittent occlusion. When not completely turning off the lower half of the glass of the leading eye is used, this is a type of partial occlusion.

Prevention of vascular obstruction is the management healthy lifestyle life and neglect it is not worth it, so that there is no direct threat. It is necessary to follow all the recommendations of the doctor and do not be afraid of surgery, if necessary.

The information on the site is provided for informational purposes only and is not a guide to action. Do not self-medicate. Consult with your physician.

Carotid occlusion

Occlusion of the carotid arteries - partial or complete obstruction of the lumen of the carotid arteries that supply blood to the brain. It may have an asymptomatic course, but is more often manifested by repeated TIA, a clinic of chronic cerebral ischemia, ischemic strokes in the basin of the middle and anterior cerebral arteries. Diagnostic search for occlusion of the carotid arteries is aimed at establishing the location, genesis and degree of obturation. It includes ultrasound of the carotid vessels, cerebral angiography, magnetic resonance angiography, CT or MRI of the brain. The most effective surgical treatment is endarterectomy, stenting the affected area of ​​the artery or creating a bypass vascular shunt.

Carotid occlusion

Modern studies in the field of neurology have shown that in most patients suffering from cerebral ischemia, the extracranial (extracranial) sections of the vessels supplying the brain with blood are affected. Intracranial (intracranial) vascular changes are detected 4 times less frequently. At the same time, occlusion of the carotid arteries accounts for about 56% of cases of cerebral ischemia and causes up to 30% of strokes.

Occlusion of the carotid arteries may be partial, when there is only a narrowing of the lumen of the vessel. In such cases, the term "stenosis" is more commonly used. Complete occlusion is an obstruction of the entire diameter of the artery and, in acute development, often leads to ischemic stroke, and in some cases to sudden death.

Anatomy of the carotid system

The left common carotid artery (CCA) originates from the aortic arch, while the right one originates from the brachiocephalic trunk. Both of them rise vertically and in the neck are localized in front of the transverse processes of the cervical vertebrae. At the level of the thyroid cartilage, each CCA divides into internal (ICA) and external (ECA) carotid arteries. The ECA is responsible for the blood supply to the tissues of the face and head, other extracranial structures and part of the hard meninges. The ICA passes through a canal in the temporal bone into the cranial cavity and provides intracranial blood supply. It nourishes the pituitary gland, frontal, temporal and parietal lobes of the brain of the same side. The ophthalmic artery departs from the ICA, providing blood supply to various structures eyeball and eye sockets. In the region of the cavernous sinus, the ICA gives rise to a branch that anastomoses with the branch of the ECA, passing to the inner surface of the base of the skull through the opening of the sphenoid bone. This anastomosis leads to collateral circulation during ICA obturation.

Causes of carotid occlusion

The most frequently occurring etiological factor occlusion of the carotid arteries favors atherosclerosis. Atherosclerotic plaque is located inside on the vascular wall and consists of cholesterol, fats, blood cells (mainly platelets). As the atherosclerotic plaque grows, it can cause complete occlusion of the carotid artery. On the surface of the plaque, the formation of a thrombus is possible, which, with the blood flow, moves further along the vascular bed and becomes the cause of thrombosis of the intracranial vessels. With incomplete occlusion, break away from vascular wall maybe the plaque itself. Then it turns into an embolus that can lead to thromboembolism of cerebral vessels of a smaller caliber.

Obstruction of the carotid arteries can also be caused by other pathological processes of the vascular wall, for example, with fibromuscular dysplasia, Horton's disease, Takayasu's arteritis, Moyamoya disease. Traumatic occlusion of the carotid arteries develops as a result of TBI and is caused by the formation of a subintimal hematoma. Other etiofactors include hypercoagulable conditions (thrombocytosis, sickle cell anemia, antiphospholipid syndrome), homocystinuria, cardiogenic embolism (with valvular acquired and congenital heart disease, bacterial endocarditis, myocardial infarction, atrial fibrillation with thrombus formation), tumors.

Factors contributing to stenosis and obturation of the carotid arteries are: features of the anatomy of these vessels (hypoplasia, tortuosity, kinking), diabetes mellitus, smoking, malnutrition with a high content of animal fats in the diet, obesity, etc.

The clinic of carotid artery obstruction depends on the location of the lesion, the rate of development of occlusion (suddenly or gradually) and the degree of development of vascular collaterals that provide alternative blood supply to the same areas of the brain. With the gradual development of occlusion, the blood supply is restructured due to collateral vessels and some adaptation of the brain cells to the prevailing conditions (reduced supply of nutrients and oxygen); a clinic of chronic cerebral ischemia is being formed. The bilateral nature of the obturation has more severe course and less favorable prognosis. Sudden occlusion of the carotid arteries usually leads to ischemic stroke.

In most cases, carotid artery occlusion manifests as a transient ischemic attack (TIA) - a transient disorder of cerebral circulation, the duration of which primarily depends on the degree of development of the vascular collaterals of the affected area of ​​the brain. The most typical symptoms of TIA in the carotid system are mono- or hemiparesis and sensory disturbances on the opposite side (heterolaterally) in combination with monocular visual disturbances on the side of the lesion (homolaterally). Usually, the onset of an attack is the occurrence of numbness or paresthesia of half of the face and fingers, the development of muscle weakness in the entire arm or only in its distal sections. Visual disturbances range from the sensation of spots before the eyes to a significant decrease in visual acuity. In some cases, retinal infarction is possible, triggering the development of optic nerve atrophy. Rarer manifestations of TIA in carotid artery obstruction include: dysarthria, aphasia, facial paresis, headache. Some patients indicate dizziness, lightheadedness, swallowing disorders, visual hallucinations. In 3% of cases, local convulsions or major epileptic seizures are observed.

According to various sources, the risk of ischemic stroke within 1 year after the onset of a TIA ranges from 12 to 25%. Approximately 1/3 of patients with carotid artery occlusion have a stroke after one or more TIAs, and 1/3 develop without previous TIAs. Another 1/3 are patients in whom ischemic stroke is not observed, but TIA continues to occur. The clinical picture of ischemic stroke is similar to the symptoms of TIA, however, it has a persistent course, i.e. neurological deficit (paresis, hypoesthesia, visual disturbances) does not disappear with time and can only decrease as a result of timely adequate treatment.

In some cases, the manifestations of occlusion do not have an abrupt onset and are so subtle that it is very difficult to assume a vascular genesis of the problems that have arisen. The patient's condition is often interpreted as a clinical picture of a cerebral tumor or dementia. Some authors point out that irritability, depression, confusion, hypersomnia, emotional lability and dementia can develop as a result of occlusion or microembolism of the ICA on the dominant side or on both sides.

Obturation of the common carotid artery occurs only in 1% of cases. If it develops against the background of normal patency of the ECA and ICA, then the collateral blood flow through the ECA to the ICA is sufficient to avoid ischemic brain damage. However, as a rule, atherosclerotic changes in the carotid arteries are multilevel, which leads to the occurrence of the symptoms of occlusion described above.

Bilateral type of occlusion of the carotid arteries with well-developed collaterals may have an asymptomatic course. But more often it leads to bilateral strokes of the cerebral hemispheres, manifested by spastic tetraplegia and coma.

Diagnosis of occlusion of the carotid arteries

In diagnostics, along with a neurological examination of the patient and the study of anamnesis data, instrumental methods studies of the carotid arteries. The most accessible, safe and fairly informative method is USDG of vessels head and neck. In case of occlusion of the carotid arteries, ultrasonography of the extracranial vessels usually reveals accelerated retrograde blood flow along the superficial branches of the ECA. Under conditions of occlusion, blood moves along them to the ophthalmic artery, and through it to the ICA. During ultrasound, a test is performed with compression of one of the superficial branches of the ECA (usually the temporal artery). A decrease in blood flow in the ophthalmic artery with digital compression of the temporal artery indicates occlusion of the ICA.

Angiography of the cerebral vessels allows you to accurately determine the level of occlusion of the carotid arteries. However, due to the risk of complications, it can only be performed in difficult diagnostic cases or immediately before surgical treatment. An excellent and safe replacement for angiography has become MRA - magnetic resonance angiography. Today, in many clinics, MRA in combination with MRI of the brain is the "gold standard" for diagnosing carotid artery occlusion.

Ischemic damage to cerebral structures is visualized using MRI or CT of the brain. At the same time, the presence of "white" ischemia indicates a gradual atherosclerotic nature of the obstruction of the carotid arteries, and ischemia with hemorrhagic impregnation indicates an embolic type of lesion. It should also be taken into account that in approximately 30% of patients with ischemic stroke, focal changes in brain tissues are not visualized in the first days.

With regard to occlusion of the carotid arteries, it is possible to use various surgical tactics, the choice of which depends on the type, level and degree of obstruction, the state of collateral circulation. In cases where the operation is performed after 6-8 hours from the onset of a progressive ischemic stroke, the mortality rate of patients reaches 40%. In this regard, surgical treatment is advisable before the development of a stroke and has preventive value. As a rule, it is carried out in the intervals between TIAs when the patient's condition stabilizes. Surgical treatment is carried out mainly with extracranial type of occlusion.

Among the indications for surgical treatment of stenosis and obstruction of the carotid arteries, there are: a recent TIA, a completed ischemic stroke with minimal neurological disorders, asymptomatic occlusion of the cervical region of the ICA more than 70%, the existence of sources of embolism in the extracranial arteries, the syndrome of insufficient arterial blood supply brain.

With partial occlusion of the carotid arteries, the operations of choice are: stenting and carotid endarterectomy (eversion or classic). Complete obturation of the vascular lumen is an indication for the creation of an extra-intracranial anastomosis - a new path of blood supply, bypassing the occluded area. If the lumen of the ICA is preserved, subclavian-common sleep prosthetics is recommended; if it is obturated, subclavian-external carotid prosthetics are recommended.

Forecast and prevention

According to the generalized data, asymptomatic partial occlusion of the carotid arteries up to 60% in 11 cases out of 100 is accompanied by the development of a stroke within 5 years. With a narrowing of the lumen of the artery to 75%, the risk of ischemic stroke is 5.5% per year. In 40% of patients with complete occlusion of the ICA, ischemic stroke develops in the first year of its occurrence. Preventive surgical treatment minimizes the risk of stroke.

Measures aimed at the prevention of arterial occlusion include getting rid of bad habits, proper nutrition, fighting overweight, correction lipid profile blood, timely treatment of cardiovascular diseases, vasculitis and hereditary pathology (for example, various coagulopathy).

Occlusion of the carotid arteries - treatment in Moscow

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Occlusion of the right sun

Symptoms of carotid occlusion

• Stage I - asymptomatic, arteriography reveals arterial stenosis, the danger of which is thromboembolism,
• Stage II - a high degree of vasoconstriction with intermittent ischemia with syncope, hemiparesis lasting several minutes, aphasia, impaired gait and sensitivity (transient ischemic attack). Complications - thrombosis of small cerebral vessels;
• Stage III - complete occlusion of the artery, manifested by sudden apoplexy with loss of consciousness, a complete picture of apoplexy stroke;
• Stage IV - the remaining neurological signs after a stroke.

Treatment of carotid occlusion

In the case of a preserved internal carotid artery, subclavian-common carotid prosthetics is performed, which consists in the formation of an anastomosis between the subclavian artery and the common carotid artery above the site of occlusion. This operation allows you to restore the normal blood supply to the brain through the internal carotid artery. In cases where the internal carotid artery is also occluded, a subclavian-external carotid prosthesis is performed. This operation allows you to restore normal blood flow to the external carotid artery, which is a necessary condition for creating an extra-intracranial microvascular anastomosis between the superficial temporal artery and the cortical branch of the middle cerebral artery in the future. The operation is carried out only general anesthesia, two linear incisions are made: one on the anterior-lateral surface of the neck 7-10 cm long to access the bifurcation of the common carotid artery, the second parallel to the upper line of the clavicle 6-7 cm long to access the subclavian artery. The duration of the operation is 3-4 hours.

The information in this section is intended for medical and pharmaceutical professionals and should not be used for self-medication. The information is provided for informational purposes and cannot be considered official.

Occlusion of the internal carotid artery

Occlusion of the internal carotid artery (ICA) is a narrowing of the lumen with partial or complete blockage of blood flow through the vessel supplying the brain and leading to its ischemia (oxygen starvation). With chronic ICA occlusion, the risk of stroke is more than 30%.

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Causes

• Atherosclerosis - formed on the wall of an artery cholesterol plaque can completely block the lumen of the vessel and become a serious obstacle to the normal blood supply to the brain. Also, a blood clot (thrombus) is formed on the surface of the plaque, which enters the vascular bed of the brain with the bloodstream and causes thrombosis of the cerebral arteries. With incomplete occlusion, the plaque itself can break away from the vascular wall and cause thromboembolism of smaller cerebral vessels.
• Pathological processes of the vascular wall - fibromuscular dysplasia, Horton's disease, Moya-Moya disease, etc.
• Traumatic factors - hematomas in traumatic brain injuries.
• Cardiovascular pathologies with the formation of blood clots.
• Tumors.

Symptoms

• Stage 1 is asymptomatic. Arteriography revealed stenosis of the ICA. A complication is the development of thromboembolism.
• Stage 2 - the degree of narrowing of the vessel is high. The patient may experience short-term hemiparesis (unilateral paralysis and impaired motor activity), aphasia (speech impairment), changes in gait and decreased sensitivity. A complication at this stage is thrombosis of small vessels of the brain.
• Stage 3 - complete occlusion of the ICA, manifested by sudden apoplexy with loss of consciousness and a complete clinical picture of apoplexy stroke.
• Stage 4 - residual neurological disorders after a stroke (acute cerebrovascular accident).

Treatment of ICA occlusion

Treatment of the disease is only surgical. Endovascular operations are performed, which have proven their high efficiency and the safety of physiological restoration of cerebral circulation in practice - up to 100% of cases of complete cure without the risk of recurrent strokes.

Thanks to the use of modern medical technologies, recanalization (stenting) in chronic ICA occlusion makes it possible to restore the arterial lumen, even if it is narrowed by 70%. The whole procedure lasts no more than 1 hour, during which a flexible self-expanding stent is installed in the narrowed part of the vessel, which does not injure the walls and optimally adapts to the physiological curves of the artery.

For the operation, microsurgical techniques are used, and all the manipulations of the surgeon are controlled by a computer, which makes it possible to restore the lumen in the carotid arteries even in the most inaccessible places. Endovascular surgery is the best option for those patients who are contraindicated in traditional surgical treatment.

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Occlusion of the right sun

The most dramatic complication of any type of plaque, or the result of its natural evolution, is occlusion of the arterial lumen by supraplaque thrombosis or plaque material.

signs

Diagnosis can be made with duplex scanning based on the following indications:

• the absence of the Doppler spectrum of blood flow in the artery and the color staining of its lumen;
• the lumen of the artery is filled with echo structures of varying echogenicity;
• lack of normal (radial) pulsation of the arterial walls (upon careful examination, it is noted forward movement of the entire vessel to the beat of cardiac activity);
• the diameter of the artery is reduced compared to the intact contralateral artery;
• with occlusion of the ICA, the blood flow velocity in the ipsilateral CCA decreases both in systole and (to a greater extent) in diastole;
• blood flow velocity in the pool providing collateral circulation (ipsilateral vertebral artery or contralateral ICA) increases compensatory.

Difficulties in diagnosis

Difficulties in diagnosing ICA occlusion arise with poor image quality, high level bifurcation, the presence of a plaque that gives an ultrasonic “shadow”, as well as when distinguishing between occlusion and subtotal stenosis, especially if the stenosing plaque is prolonged, eccentrically located, and the lumen has a tortuous course.

Scanning

Careful scanning of the distal part of the artery with the interrogated volume, the use of color flow mapping allow, on the one hand, to avoid overdiagnosis of occlusion in the case of a stenosing lesion, and on the other hand, to answer the vitally important question for the patient about the presence or absence of a passable distal bed and, therefore, about the possibility of reconstructive surgery.

Determination of further treatment tactics

In case of occlusion of the CCA, to determine the further tactics of treating the patient, it is fundamentally important to identify the patency of the bifurcation. In some cases, the ICA can fill collaterally through branches of the ipsilateral ECA from the contralateral ECA. In these cases, when performing color flow in the bifurcation area, multidirectional flows are visualized - antegrade (in the ICA) and retrograde (in the ECA and its branches); when the contralateral CCA is compressed, blood flow stops (Fig. 14.25).

Rice. 14.25. Occlusion of the internal carotid artery. Image in color flow mode

It is possible to differentiate the ICA and the ECA only in the direction of blood flow, since the blood flow velocity in both arteries is reduced both in systole and diastole, and the shape of the curve is significantly smoothed.

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Carotid artery occlusion is called pathological condition which causes blockage of the arteries. It is partial and complete. Mostly adults are ill, which is due to the presence of chronic diseases (atherosclerosis, thrombosis). Occlusion is dangerous because it can lead to transient ischemic attacks, stroke and sudden death.

Causes

Risk factors for blockage of the carotid arteries are:

1. atherosclerotic plaques. They are formed as a result of a violation of lipid metabolism, when low-density lipoproteins and calcium salts are deposited on the walls of the carotid arteries. Causes can be hereditary dyslipidemia, addiction to fatty foods, baked goods and sweets, obesity, low physical activity and burdened heredity.
2. Embolism. The vessel is clogged with a thrombus or detached atherosclerotic plaque.
3. Thrombosis. The cause may be hypercoagulability (increased blood clotting).
4. Sickle cell anemia.
5. Hereditary disorder of methionine metabolism.
6. antiphospholipid syndrome.
7. Myocardial infarction.
8. Tumors.
9. Atrial fibrillation.
10. Heart defects with valvular lesions.
11. Fibromuscular dysplasia. This pathology characterized by a violation of the distribution of collagen in the arteries and the formation of fibromuscular fibers.
12. Giant cell temporal arteritis. This is autoimmune disease, in which circulating immune complexes damage the walls of the arteries.
13. Nonspecific aortoarteritis (Takayasu's disease).
14. Moyamoya disease. It is characterized by narrowing of the internal carotid artery (ICA) and the formation of collaterals (bypass routes for the movement of blood).
15. Hematomas. Most often they are the result of an injury (bruise).
16. Thrombocytosis (an abnormal increase in white blood cells in the blood).
17. Infective endocarditis.

Occlusion often occurs in patients diabetes, smokers and obese people.

Stages of formation

The disease proceeds in several stages. Initially, there is a partial (incomplete) blockage of the artery. The blood flow is preserved, but the amount of blood entering the brain per unit of time decreases. As a result, chronic hypoxia and cerebral ischemia develop. At this stage, the following symptoms are possible:

• movement disorders;
• headache;
• memory impairment and decreased attention;
• decreased ability to learn;
• emotional inertia (instability);
• loss of interest;
• impaired thinking;
• irritability;
• anxiety.

In violation of the patency of the carotid arteries, transient ischemic attacks often occur. They are characterized by the following manifestations:

1. Monoparesis or hemiparesis (limitation of movements in one or two limbs on 1 side).
2. Loss of sensation on the other side. Numbness and paresthesias are possible.
3. Muscle weakness.
4. Difficulty swallowing.
5. Dizziness.
6. Nausea.
7. Confusion of consciousness.
8. Convulsions and epileptic seizures.
9. Visual disturbances in the form of spots before the eyes, decreased visual acuity and nystagmus. In severe cases, optic nerve atrophy occurs. Only sometimes with partial occlusion, speech disorders are observed.

With severe (more than 70%) occlusion of the internal carotid artery, an acute circulatory disorder similar to a stroke can develop. This stage is characterized by:

1. Apraxia. The ability to perform any actions in the desired sequence is impaired.
2. Aphasia. The person is unable to speak or does not understand the speech of others.
3. Dysarthria (impaired pronunciation of words and phrases).
4. Anosognosia (the inability of a person to assess their state of health).
5. Aprosody (a violation of speech, manifested in the wrong setting of stress, intonation and tone fluctuation).
6. Violation of sensitivity.
7. Hemiparesis.
8. Emotional disorders.
9. Bilateral blindness.

With bilateral occlusion, the clinical picture is most pronounced. Tetraplegia (complete paralysis of 4 limbs) and coma often occur.

Treatment

This pathology is treated surgically. The operation is recommended to be carried out in advance (before the development of a stroke). Otherwise, the likelihood of death is high. The following types of surgical interventions are possible:

1. Stenting. It involves the expansion of blood vessels with a stent or balloon. Stenting is effective for partial occlusion of the vessel.
2. Carotid endarterectomy (removal of a section of the affected artery).
3. Anastomosis formation. It is indicated for complete obstruction of the carotid artery.
4. Prosthetics.

In addition to the main therapy are:

1. Head and neck massage.
2. Strict diet. With atherosclerosis, it is recommended to give up fatty foods, alcohol, sweets, pastries and limit salt intake.
3. Treatment of thrombosis and other diseases that provoked blockage of the carotid arteries.
4. Taking medication. Statins (Aterostat, Rosucard), antihypoxants (Actovegin), antioxidants (Mexidol), metabolic agents (Glycine), nootropics (Cerebrolysin, Encephabol), antiplatelet agents (Curantil), fibrinolytics (Streptokinase), adaptogens and drugs that improve blood circulation (Vinpocetine) may be prescribed. , Trental).
5. Physiotherapy.

Self-treatment for vascular obstruction is unacceptable.

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Stenosis (narrowing) of the carotid arteries: how it develops, signs and degrees, treatment

Cerebrovascular diseases are one of the most significant problems of modern medicine. Mortality from vascular accidents of the brain occupies a leading position among other diseases, and the frequency of disability is extremely high.

Carotid stenosis occurs in the brain in about a third of all strokes. When the lumen of the internal carotid artery is closed by more than 70%, cerebral infarction occurs in almost half of the patients during the first year. after significant disruption. Early diagnosis and timely resolution of the problem can help prevent this. dangerous consequences. Modern surgical methods of treatment are safe, and with early detection of pathology, minimally invasive treatment is possible, which does not require large incisions and general anesthesia.

The carotid arteries depart from the aorta, go in the tissues of the anterior-lateral surface of the neck to the head, where they are divided into external and internal branches, carrying blood further to the vessels of the brain and head tissues. Stenosis can appear in any of the areas, but most likely in places of narrowing (mouth, division into branches).

The main volume of blood enters the brain through these large arterial trunks, so any disturbances in them lead to hypoxia and require immediate examination and treatment. If in the USA the number of surgical corrections of stenosis reaches 100,000 per year, then in Russia only about 5,000 of them are performed. Such a low figure does not allow covering all those who need treatment, and this is one of the significant problems of the healthcare system.

Another problem is the late detection of pathology or the patient’s unwillingness to “go under the surgeon’s knife”, however, all patients with critical stenoses should be aware that the operation is the only way avoid stroke and save lives.

Causes of narrowing of the carotid artery

Its rather high prevalence of narrowing of the carotid artery is due to risk factors that affect a large number of people, especially the elderly. Vascular pathologies contribute to:

• Heredity;
• Bad habits, in particular smoking;
• High blood pressure;
• Disorders of carbohydrate metabolism (diabetes mellitus);
• Old age and male gender;
• Overweight, lack of physical activity.

If the family already has patients suffering from narrowing of the carotid arteries, then it is likely that other blood relatives may have a hereditary predisposition to pathology. Apparently, it is based on genetic mechanisms of propensity to disorders of fat metabolism.

Common conditions such as obesity also provoke atherosclerosis of the carotid arteries. Excessive pressure changes the structure of the vascular walls, makes them dense and vulnerable, promotes the accumulation of lipids there, and the combination of atherosclerosis with high pressure significantly increases the risk.

With age, the likelihood of structural damage to the walls of the carotid arteries increases, so the pathology is usually diagnosed in the 6-7th decade of life. In men, this process occurs earlier, and in women, the sex hormones estrogen perform a protective function, so they get sick later, after menopause.

Stenosis of the carotid artery against the background of atherosclerosis can be aggravated, among which kinks, loops, and tortuosity are quite common. In these zones, an increased likelihood of endothelial damage by turbulent blood flows is created, atherosclerosis progresses, and hemodynamically significant stenosis can manifest earlier, compared with the direct course of the vessel.

The morphological basis of stenosis of the vessels of the neck is. The pathology of the metabolism of fats and carbohydrates provokes the deposition of fat not only in the aorta, coronary and cerebral arteries, but also in the vessels of the neck, as a result of which blood delivery to the brain is difficult.

A plaque in the carotid artery does not manifest itself for the time being, especially with unilateral localization. With its gradual increase, the lumen of the vessel narrows more and more, and there are signs of a lack of blood flow in the head - chronic ischemia, clinically expressed in.

With a relatively intact blood flow through the main arteries of the neck, the phenomena of chronic ischemia will gradually progress, but when the plaque is destroyed, thrombosis will inevitably develop with complete blockage of the vessel. This is one of the most dangerous manifestations stenosis of the carotid arteries, which is accompanied by necrosis of the brain tissue (stroke).

Depending on the prevalence of damage to the vascular walls, focal atherosclerosis is distinguished (over one to one and a half centimeters) and prolonged, when plaques occupy more than 1.5 cm of the length of the artery.

To assess the risk of vascular accidents and determine the indications for surgical treatment, it is customary to distinguish several degrees of narrowing of the carotid arteries, determined by the percentage of stenosis of the lumen of the vessels:

• Up to 50% - hemodynamically insignificant narrowing, which compensated by collateral blood flow;
• 50-69% - pronounced narrowing, manifested clinically;
• Stenosis up to 79% is subcritical, the risk of acute circulatory disorders is very high;
• Critical stenosis, when the lumen of the artery is narrowed by 80% or more.

The most susceptible to the atherosclerotic process are the initial sections of the common carotid artery, the place of its division into the external and internal branches and their mouths.

Manifestations and diagnosis of carotid stenosis

There are no specific symptoms that speak specifically of carotid artery stenosis. Since the narrowed artery cannot deliver the required volume of blood to the brain, the symptoms will consist of signs of ischemia in the brain. The narrowing of half of the lumen of the vessel does not cause hemodynamically significant disorders, so it goes unnoticed by the patient. As the degree of stenosis increases, clinical signs will also appear.

The first "bells" that speak of trouble can be, which are accompanied by:

1. headache;
2. Dizziness and imbalance;
3. Feeling of numbness in the face, limbs;
4. Indistinctness of words, impaired understanding of addressed speech, as a result of which contact with the patient is difficult;
5. visual disturbances;
6. Fainting.

The listed symptoms are short-term, usually lasting about half an hour, and then gradually regress, and by the end of the first day there is no trace of them. However, even in the case when the condition is completely normal, you need to consult a doctor to clarify the cause of ischemia in the brain. In the presence of past TIAs, the risk of stroke increases tenfold, so these attacks can be regarded as precursors of cerebral infarction and should not be ignored.

Against the background of stenosis of the arteries of the neck, it is manifested by a decrease in working capacity, a weakening of memory, difficulties in concentrating, and changes in behavior. Signs of such dyscirculatory encephalopathy can become noticeable, first of all, to those around them, who will notice that their loved one or colleague is changing in character, it is more difficult for him to cope with his usual duties, it is more difficult to reach mutual understanding when communicating, while the patient himself will try to lead a familiar image life, “writing off” the symptoms for fatigue or age.

Critical stenosis of the right or left carotid artery can lead to much more serious consequences than TIA. A large atherosclerotic plaque can rupture with the release of its contents to the surface of the vascular wall, while thrombosis necessarily develops, and the resulting clot completely clogs the artery, leaving it no opportunity to deliver blood to the brain.

The result of a complete cessation of blood flow through the carotid artery is ischemic stroke - cerebral infarction, in which nerve cells die in the area of ​​blood supply to the affected artery. A thrombus or its fragments can break off and move into smaller vessels - the basilar, cerebral arteries, and then the symptoms of a stroke will be caused by damage to a particular vascular pool.

Consider paralysis, paresis, loss of consciousness, speech disorders, swallowing, sensitivity. In severe cases, a cerebral coma occurs, the activity of the cardiovascular and respiratory system. These symptoms often occur suddenly, against the background of a severe headache, can take a person by surprise at the workplace, on the street or at home. It is important that those around you quickly orient themselves and call an ambulance, because the speed of rendering qualified assistance both life and the prognosis of the disease depend.

Based on the predominant symptoms, several options for the course of pathology:

• Asymptomatic form, when there are no signs of ischemia in the brain, but stenosis has already been identified with the help of an additional examination;
• Dyscirculatory encephalopathy - chronic ischemia without focal symptoms of brain damage;
• Transient ischemic attacks - can occur with focal neurological disorders that disappear within a day;
• Consequences - symptoms disappear within a month;
• Stroke (cerebral infarction) is an acute violation of blood flow with cerebral and focal symptoms.

The prognosis of the disease depends not only on the severity of stenosis, but also on how early the pathology is detected. In this regard, a timely visit to a doctor, even if the symptoms of the disease have disappeared without a trace, is necessary.

One of the first signs of stenosis, which can be detected already during the initial visit to the doctor, is considered a kind of noise over the artery when it is listened to. To confirm the diagnosis, a variety of instrumental examinations are used - CT, MRI, ultrasound, angiography.

The most accessible, safe and cheap way to diagnose stenosis of the arteries of the neck is the ultrasound method, supplemented by Doppler sonography. The specialist evaluates the structure of the vessel wall and the nature of the blood flow through it.

CT and MRI can exclude other causes of circulatory pathology, and radiopaque angiography can accurately localize the site of narrowing. Contrasting is also used at the stage of surgical correction of stenosis.

Treatment of carotid stenosis

For the treatment of stenosis of the vessels of the neck and the disorders of blood flow caused by them in the head, they are used medical methods and surgical operations.

Conservative therapy is aimed at improving brain activity, protecting it from pernicious influence hypoxia, for which nootropic and metabolic drugs are prescribed - piracetam, mildronate, B vitamins.

Mandatory component drug therapy becomes a correction of blood pressure. Hypertensive patients should take constantly, according to the scheme proposed by the doctor. Hypotension patients should be careful and also control the pressure, as its decrease will cause aggravation oxygen starvation brain.

With atherosclerotic plaques in the carotid arteries, and this is the most common cause of pathology, drugs that normalize fat metabolism are indicated (), a diet and rational physical activity are necessary.

Drug treatment can somewhat improve brain activity in non-critical stenosis and plays an auxiliary role after surgery, but with decompensated narrowing of the artery, recurrent ischemic attacks, or a stroke, surgery is indispensable.

Indications for surgical treatment are:

1. Arterial stenoses of more than 70%, not even accompanied by obvious clinical symptoms;
2. Conditions after a stroke associated with damage to the carotid arteries;
3. Recurrent TIA with stenosis of 50% or more.

Surgery for carotid artery stenosis is aimed at restoring normal blood flow and can be radical or minimally invasive. Radical interventions are carried out open way, minimally invasive - without a large skin incision.

radical treatment – carotid – an open operation, in which an incision is made in the neck in the area of ​​the passage of the vessel, the artery is exposed, the surgeon finds the place of narrowing and removes the plaques together in the area of ​​the vascular wall, then the integrity of the vessel is restored by plasty, and the wound is sutured. With concomitant kinking, looping, and tortuosity, the entire affected fragment of the artery can be removed. The operation requires general anesthesia.

carotid endarterectomy

Stenting - a more gentle method of treatment, which consists in introducing a special tube into the lumen of the vessel, which expands it and maintains it in a straightened form, providing blood flow. The purpose of such an operation is to prevent possible vascular catastrophes and minimize the manifestations of chronic hypoxia, therefore it is indicated for subcritical constrictions.

Stenting is performed under local anesthesia with constant control of pressure and pulse of the patient. The femoral artery through which the conductor is inserted is punctured, a catheter and a contrast agent are placed into it to accurately determine the location of the stent. The operation is performed under fluoroscopic control, but the dose of radiation received is minimal and does not pose a danger.

stenting scheme

The stent is installed at the site of stenosis of the left or right carotid artery, it straightens out, it is possible to use special balloons that inflate the vessel at the site of narrowing. To prevent thromboembolic complications with damage to smaller arterial vessels of the brain during surgery, special filters are installed in the artery that do not interfere with blood flow, but delay tiny particles blood clots.

Once the stent is in place, the filters and catheter are removed and the stent remains in place. The intervention lasts no more than an hour, after which the patient can be sent to intensive care for a while or immediately transferred to the ward. For the first day, strict bed rest is recommended; there are no restrictions on food and fluid intake in the postoperative period.

The duration of hospitalization for surgical treatment is determined individually. After stenting, the patient spends 2-3 days in the hospital, after which he can go home. Open operation requires a longer observation - about a week, at the end of which skin sutures are removed.

The prognosis after timely correction of blood flow is favorable, but the patient should know that it does not protect against re-damage of this vessel or other arteries of the head and neck, therefore, maintaining a healthy lifestyle, normalizing nutrition, maintaining a normal level of pressure are the most important preventive actions, which cannot be neglected.

Prevention of carotid stenosis against the background of atherosclerotic lesions includes special diet, rational motor activity, the fight against excess weight, smoking cessation and drug treatment of existing cardiovascular and metabolic pathology. In addition, you should regularly visit doctors for a routine medical examination.

Video: carotid artery stenosis in the program “Live great!”

a. Doppler Criteria

Periorbital dopplerography

With occlusion of the ICA (Fig. 44), three options for the direction of blood flow in the supratrochlear artery are possible:

Fig.44. ICA occlusion.
1- OCA, 2- ICA stump, 3- NCA.

Retrograde blood flow in the supratrochlear artery during ICA occlusion indicates the inclusion of the ophthalmic anastomosis, which, as noted above, does not yet indicate that this anastomosis is the only one in collateral compensation. The results of compression tests are the same as in the presence of a sharp stenosis of the ICA (Fig. 45).

Fig.45. Retrograde blood flow in the supraorbital artery during ICA occlusion.

Antegrade blood flow in the supratrochlear artery on the side of the lesion occurs in the presence of a powerful overflow along the PSA from the opposite carotid artery. Compression of the homolateral CCA does not lead to a change in the magnitude of antegrade blood flow in the supratrochlear artery. Compression of the contralateral common carotid artery results in a sharp decline or supratrochlear flow inversion, indicating blood supply to the occluded internal carotid artery from the contralateral common carotid artery via the PSA. Much less often, antegrade blood flow in the supratrochlear artery does not respond to compression of both the same-named and contralateral common carotid artery, which indicates collateral blood supply from the vertebrobasilar basin through the PCA with functional or anatomical failure of the anterior communicating artery. -- The absence of blood flow in the supratrochlear artery is a very rare phenomenon, indicating, most likely, the failure of the ophthalmic anastomosis and insufficient PSA function in order to fill the branches of the ophthalmic artery. In general, periorbital Doppler sonography provides a rather superficial idea of ​​the state of collateral circulation in ICA occlusion. It is most accurately diagnosed by the TKD method.

Carotid Dopplerography The most reliable sign of the absence of blood flow in the projection of the ICA location, confirmed in unclear cases by D. Russel test. The remaining criteria are of an auxiliary nature.

Transcranial Dopplerography As well as in case of ICA stenoses, TCD has no independent determining value in the direct diagnosis of ICA occlusion. However, for determining the state of collateral circulation and assessing the reserve of collateral compensation, TCD is the main method. Criteria for diagnosing collateral circulation in ICA occlusion Sometimes, during a background study of blood flow in the MCA or ACA, a spectrum with typical characteristics of collateral blood flow is recorded on the side of occlusion (low systolic and high diastolic components of the spectrum with a decrease in the average blood flow velocity and low PI) (Fig. 46).

Fig.46. Collateral nature of blood flow in the MCA with occlusion of the ICA. The absence of response to compression of the homolateral CCA and the reduction of blood flow during compression of the contralateral CCA indicate the presence of collateral compensation of blood circulation in the MCA or ACA basin on the side of ICA occlusion through the ACA (Fig. 47).

Fig.47. Collateral blood flow in the MCA from the contralateral carotid
pool through the PSA with occlusion of the ICA.

Collateral circulation through the posterior communicating artery is diagnosed in the absence of changes in blood flow in the middle cerebral artery from the side of ICA occlusion with sequential compression of both CCAs (Fig. 48).

Fig.48. Collateral blood flow in the MCA from the vertebrobasilar basin
with ICA occlusion.

Quite often, collateral circulation can be carried out through two or more ways of collateral circulation. With TCD, it is realistic to diagnose a combination of collateral overflows through the ophthalmic anastomosis and PSA (Fig. 49).

Fig.49. a - location of retrograde blood flow in the ophthalmic artery
through the orbital window;
b- location of blood flow in the MCA through the PSA.

It is also possible to identify the combined function of the ophthalmic anastomosis with overflow along the PCA. It is practically difficult to diagnose the combination of flows by PSA and SSA. The state of the cerebral perfusion reserve (CPR) according to the TCD data. The study of the state of collateral circulation in the basin of the occluded carotid artery is very important for determining the tactics of treatment and prognosis of the disease. A high perfusion reserve determines a more favorable prognosis for the further course of cerebrovascular insufficiency, a low reserve of collateral circulation is one of the most important components in determining indications for surgical treatment. The control of changes in blood flow in the middle cerebral artery from the side of ICA occlusion is most often carried out using TCD. The complex of equipment for carrying out an activation test includes a system for obtaining a 5-6% mixture of carbon dioxide with air, injected into a bag, from which inhalation is carried out through a hose system, and a mouthpiece with a valve. The inhalation system works on the principle of a semi-open circuit, when the gas mixture is inhaled from the bag, and exhaled into the environment. The outlet hose is connected to a capnograph that measures the carbon dioxide tension (pCO2) in the exhaled air. The scheme of the activation test for determining the CPR is shown in fig. fifty.

Fig.50. Scheme of the activation test with carbon dioxide
with the help of TKD

The first stage of the study is air inhalation with simultaneous recording of the average blood flow velocity in the M3 segment of the middle cerebral artery using TCD (in the presence of a two-channel device - on both sides, with a single-channel recording - from the side of ICA occlusion) and carbon dioxide tension in the exhaled air. This stage of the study continues until a "plateau" is reached in terms of both MCA flow velocity and pCO2. Then the test itself is carried out - inhalation of a 5-6% mixture of air with carbon dioxide for 3-5 minutes until a new "plateau" is reached in the readings of the TCD and capnograph. After that, the test is terminated. Quantification of the so-called. CPR index is carried out according to the formula

ICPR \u003d (V1-V0) / (pCO2 "- pCO2), where V0 is the average blood flow velocity in the M3 segment at rest; V1 is the average blood flow velocity in the M3 segment after an activation test; pCO2 is the carbon dioxide tension in the exhaled air at rest; pCO2" is the tension of carbon dioxide in the exhaled air after the activation test. Calculation of pCO2 in the blood according to the formula:

pCO2 \u003d (Pa / 100%) x CO2%, where Pa is atmospheric pressure, CO2% is the percentage of carbon dioxide concentration at the end of exhalation. In healthy patients, the VMR value is 3.22 ± 0.33 cm/sec/mm Hg, while in ICA occlusion it is 0.99 ± 0.53 cm/sec/mm Hg. If the CPR value is below 1.1 cm/sec/mm .rt.st. the function of collateral sources of blood supply is in a state of decompensation, which indicates an existing risk of stroke due to possible violation general hemodynamics.

b. Indications for surgical treatment

Revascularization of the brain in ICA occlusion has long remained an insoluble problem. The first operations of thrombectomy from the ICA in the acute period of cerebral stroke in most cases were ineffective or impossible, especially when thrombosis spread to the intracranial parts of the ICA, which subsequently led to the abandonment of these operations. Numerous studies have shown that in ICA occlusion, the severity of cerebrovascular insufficiency is more a result of inadequate collateral circulation than ICA occlusion itself. In this regard, the creation of an extra-intracranial microanastomosis (EICMA) between the superficial temporal artery (STA) and the cortical branches of the middle or anterior cerebral arteries (MCA, ACA) with occlusion of the ICA (Fig. 51) is the most adequate operation aimed at brain revascularization and an increase in perfusion pressure (PP) in the area of ​​the occluded ICA.

Fig.51. Scheme of performing extracranial-intracranial
microanastomosis (EICMA) with occlusion of the internal carotid
arteries.
1 - branch of the superficial temporal artery, 2 - cortical branch of the middle
cerebral artery.

The idea of ​​creating EIKMA was first expressed in 1912 by Crutrie, and was implemented in 1967 by Donaghy and Yazargil. The introduction of this type of surgical correction into practice was regarded as a significant progress in the treatment of cerebrovascular diseases, since previously patients with ICA occlusion were considered inoperable and at high risk of recurrent strokes. At present, the main indications for the creation of EICMA have been determined. First of all, the concept of the hemodynamic significance of EICMA was formulated. The created anastomosis between the branches of the superficial temporal artery and the middle cerebral artery is hemodynamically significant when large branches or the trunk of the middle cerebral artery are filled through it (Fig. 52).

Fig.52. Right carotid angiography: autovenous graft
(arrow) between the CCA and the MCA branch.

This anastomosis was designated by us as a hemodynamically significant EICMA. If only small MCA branches located in the immediate vicinity of the anastomosis are filled, then such an anastomosis was designated as hemodynamically insignificant EICMA. Establishing the type of anastomosis is carried out using TCD, as shown in Fig. 53.

A

B

Fig.53. A. Layout of the transcranial sensor (left) and
Dopplerograms (right) in type I EICMA: PVA compression (a) is not
leads to a change in blood flow, compression of the contralateral CCA
(b) - to the reduction of blood flow.
B. Layout of the transcranial sensor (left) and
dopplerograms (right) in type II EICMA: PVA compression (a)
leads to a reduction in blood flow, compression of the contralateral CCA
(b) does not change blood flow. (Cooperberg E.B. et al. Cardiovascular Surg., 1993 (c) - Vol.1- N.6) / P> The location of retrograde blood flow in the anastomosis area with its reduction during compression of the superficial temporal artery at a depth of 25 to 55 mm undoubtedly indicates hemodynamic significance of EICMA. What are the conditions for the formation of hemodynamically significant EICMA? They are based on the objectively proven position that EICMA only makes sense if there is a low cerebral perfusion reserve (CPR) in the occluded ICA, when the collateral blood circulation through the connecting arteries of the circle of Willis and other collaterals is so "tense" that the need for additional increase in blood flow (with any unfavorable extracerebral factors) is not realized, while the risk of cerebral ischemia increases dramatically. At the same time, when the collateral circulation is well developed, the CPR is high enough to respond with an increase in blood flow in any unfavorable situation. To determine this important indicator, a situation is clinically modeled in which an increase in blood flow is necessary. A number of researchers use drug tests (diamox, nitroglycerin), others (including us) use an activation test with inhalation of a 5-6% mixture of carbon dioxide with air. The role of the CPR in determining indications for EICMA was confirmed by us on the basis of mathematical multivariate analysis. For this analysis, the following parameters were evaluated using TCD:

• the state of the communicating arteries of the circle of Willis (anterior, posterior communicating arteries) and ophthalmic anastomosis according to the criteria described in detail in this manual;
• the value of perfusion cerebral reserve (CPR);
• type of EICMA functioning (hemodynamically significant and hemodynamically insignificant).

• state of neurological deficit in points;
• condition of the communicating arteries of the circle of Willis, separately for the anterior communicating artery (ACA), posterior communicating artery (PCA) and for the ophthalmic anastomosis (GA);
• the value of the CPR index in cm/sec/mm Hg (ICPR) on the side of ICA occlusion;
• PA state;
• the volume of focal lesions of the brain tissue according to CT data (in cubic cm), including the localization of the focus - superficial or deep;
• clinical efficacy after the creation of EICMA (recovery and improvement of the condition was defined as a "positive effect", in the absence of dynamics - "no effect").

Fig.54. Prediction of hemodynamic efficiency of EICMA by the method
multivariate analysis.
1- degree of cerebrovascular insufficiency in points, 2- condition
collateral circulation through the PSA, 3- the state of the collateral
blood circulation through the PCA and ophthalmic anastomosis, 4-index cereb-
perfusion reserve (CPR), 5 - the magnitude of cerebral infarction according to
computed tomography, 6 - the size of the deep focus of cerebral infarction according to
computed tomography data, 7 - the state of the vertebral arteries according to
angiography. (Kuperberg E.B. et al. International symposium of
transcranial Doppler and intraoperative monitoring, St.Petersburg, 1995)

Fig.55. Comparison of preoperative CPR indices with EICMA types

Doppler and intraoperative monitoring, St.Petersburg, 1995) Ensuring the hemodynamic efficiency of EICMA is a necessary condition for indications for this operation. Only after a confident prediction that the anastomosis will be hemodynamically significant, it is possible to build a prediction about its clinical effectiveness. The prognosis of the clinical efficacy of EICMA (of course, with hemodynamically significant EICMA), also carried out using the method of multivariate mathematical analysis, showed (Fig. 56) that the clinical efficacy depended primarily on the initial state of the neurological status (indicator "BALL") and closely related with him indicators of the state of the brain tissue ("CT" and "GO"). A positive prognosis of clinical efficacy is possible only with a minimal amount of brain tissue damage according to computed tomography in the presence of superficial lesions, which corresponds to high values ​​of the "SCORE" indicator.

Fig.56. Prediction of clinical efficacy of EICMA by the method
multivariate analysis.
1- degree of cerebrovascular insufficiency in points, 2- state of colla-
lateral blood circulation through PSA, 3 - state of collateral circulation through PCA and ophthalmic anastomosis, 4 - magnitude of cerebral infarction according to computed tomography, 5 - magnitude of deep focus of cerebral infarction according to computed tomography, 6 - state of vertebral arteries according to angiography.
(Kuperberg E.B. et al. International symposium of transcranial
Doppler and intraoperative monitoring, St.Petersburg, 1995) Thus, hemodynamic indications for EICMA are formulated as follows: