Acute arterial obstruction (thrombosis and embolism)

1. Thrombotic vascular lesions
2. Fat embolism
3. Air embolism
4. Which vessels can be affected by embolism and how does it manifest?
5. Carotid embolism
6. Occlusion of mesenteric vessels and renal artery
7. Peripheral vascular occlusion
8. Treatment and prevention of pathology
9. Prevention and treatment of fat embolism
10. Prevention and treatment of air embolism
11. Amniotic fluid embolism
12. Causes
13. Treatment and prevention

Vascular embolism is a condition in which the lumen of a blood vessel is completely or partially blocked. This leads to disruption of blood supply, which causes oxygen starvation of tissues. If left untreated, they gradually die off as the cells stop receiving oxygen and nutrients. Vessel blockage can be caused by:

• blood clots;
• particles of adipose tissue;
• air bubbles;
• foreign objects.

Regardless of the cause, vascular embolism poses a threat to the health and life of the patient. This condition requires treatment, which can be conservative or surgical.

Thrombotic vascular lesions

It is the most common type of embolism and can occur with the following diseases:

• varicose veins;
• heart disease (heart attack, myocarditis, etc.);
• excess body weight;
• thrombophilia.

The risk of pathology increases with a hereditary predisposition to thrombosis, after extensive surgical interventions, when taking hormonal contraceptives, and low physical activity. The most dangerous for the patient are thrombotic lesions of the great vessels of the brain, kidneys and intestines. In this case, there is a direct threat to life due to the development of tissue necrosis of vital organs. If treatment is not carried out in a timely manner, the patient's life can be saved, but he may remain disabled.

If a blood clot occludes a peripheral vessel, gangrene of the limb may develop and amputation may become necessary. Thromboembolism of peripheral arteries is easier to diagnose, which helps prevent severe complications.

Pulmonary thromboembolism is very life-threatening. A blood clot can block the main trunk of the pulmonary artery or its branch. This condition occurs suddenly, and the pathology leads to a very rapid deterioration in the patient’s well-being. He develops cardiopulmonary failure, which ends in cardiac and respiratory arrest.

The main cause of the pathology is the migration of a blood clot from the veins of the lower extremities or pelvis.

Possible reasons

The reasons for the formation of blood clots and emboli in the arteries can be divided into several groups:

· pathological changes in the walls of the arteries (endarteritis, atherosclerosis, vasculitis);

· changes in blood flow that occur with aneurysms, vascular stenosis, as well as their damage (bending, compression, etc.);

· diseases that negatively affect blood clotting.

The source of arterial thromboembolism often becomes the heart in the presence of pathologies associated with cardiac arrhythmias, left ventricular aneurysm, endocarditis, etc.

Also, the formation of blood clots may be preceded by a surgical operation to replace the valve apparatus with an artificial prosthesis.

Another common source of the disease are vessels with atherosclerotic plaques.

In the development of arterial thrombosis and embolism, special attention should be paid to the functional neurovascular factor. The human central nervous system is directly involved in the regulation of blood circulation in certain areas, which is why nervous shocks and disorders often cause disturbances in coronary and cerebral circulation.

Fat embolism

Pathology occurs:

• when injecting oil solutions;
• for injuries and damage that are accompanied by bone fractures and vascular injury;
• with necrotic lesions of pancreatic tissue.

Lipid droplets enter the blood from the yellow bone marrow if the damaged bone is damaged or as a result of surgery. They are able to merge into a single whole and move with the bloodstream throughout the body. Having reached a certain size, the accumulation of adipose tissue particles blocks the lumen of the vessel. Most often, the pathology affects the tissues of the spinal cord, brain, heart, and lungs.

Air embolism

The pathology is characterized by blockage of the vessel with air or gas bubbles. The reason is:

• improper administration of intravenous injections;
• damage to large vessels;
• decompression sickness.

If a large vein is injured and the bleeding is not stopped in time, air can get inside and move with the blood along the arterial bed, which ultimately leads to a blockage. A type of air embolism is gas embolism, which is caused by the so-called decompression sickness. It develops in people who engage in scuba diving. If a person rises to the surface too quickly, the inhaled gas mixture does not have time to be absorbed. Air bubbles block the vessels and lead to embolism. The person may lose consciousness, and in severe cases, a stroke is possible.

Sources

1. Yakovlev V.N., Marchenkov Yuri Viktorovich, Panova N.S., Alekseev V.G., Moroz V.V. Fat embolism. 2013. General resuscitation;
2. Kuzmichev D. E., Skrebov R. V., Viltsev I. M., Chirkov S. V. Fat embolism. 2014. Problems of expertise in medicine;
3. Rybalko N.V. Development of Doppler detection of cerebral embolism. 2014. Bulletin of the National Medical and Surgical Center named after. N. I. Pirogova;
4. Aksenov A. A. Prevention of postoperative thrombosis in cancer patients. 2014. Bulletin of Medical Internet Conferences;
5. Dikiy S.V., Shendrikov Yu.M., Dynin P.G. Treatment tactics for patients with acute arterial embolisms. 2007. Acta Biomedica Scientifica;
6. Z. A. Suslina, A. V. Fonyakin, A. L. Kuznetsov Development of Doppler detection of cerebral embolism. 2004. Atmosphere. Cardiology news.

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Which vessels can be affected by embolism and how does it manifest?

Blockage of the lumen can occur in any vessel. Depending on the location of the pathology, its symptoms vary. Signs of arterial embolism are:

• a sharp drop in blood pressure;
• irregular pulse and breathing;
• sweating;
• pallor;
• chest pain that radiates to neighboring areas of the body;
• weakness, dizziness;
• loss of consciousness.

Carotid embolism

Signs of pathology are:

• weakness and dizziness;
• headache;
• deterioration in coordination of movements;
• fainting state.

Occlusion of mesenteric vessels and renal artery

In this case, the superior and inferior mesenteric arteries are affected. The pathology is manifested by severe abdominal pain, bloating, loose stools mixed with blood, and impaired intestinal motility.

If there is a blockage of the renal artery, the patient experiences severe pain in the lower back. The functioning of the kidney is disrupted, which causes difficulty urinating until it completely stops, and blood is released in the urine.

Peripheral vascular occlusion

Embolism of the arteries of the extremities leads to pain in the affected area, which is accompanied by spasms and muscle cramps. Due to impaired blood supply, the skin turns pale. Trophic ulcers appear on the surface - non-healing wounds that can lead to gangrene.

Treatment and prevention of pathology

Treatment of the disease depends on its type. A treatment protocol has been developed for each type of pathology. It is aimed at normalizing vital functions and eliminating the cause that led to blockage of the vessel.

Conservative therapy includes taking medications:

• anticoagulants;
• glycosides;
• fibronolytics;
• glucocorticosteroids.

If the pathology occurs due to injury or infection, antibiotics are prescribed.

A patient with thromboembolism is prescribed ozone therapy, which eliminates the lack of oxygen in tissues and has a bactericidal effect.

If drug therapy is not effective enough, surgery is performed to remove the blood clot. To prevent thromboembolism, it is necessary to regularly monitor blood clotting parameters. There is a special analysis for this - a coagulogram. If necessary, a patient at high risk of thrombosis should take anticoagulants.

Varicose veins and heart disease are factors that provoke thrombotic damage to the arteries. If you have such diseases, it is important to monitor your condition and undergo timely treatment.

Prevention and treatment of fat embolism

In case of fat embolism, the patient needs to be hospitalized in the intensive care unit and connected to a ventilator. Drug therapy involves taking drugs that dissolve fatty particles. The patient is also prescribed anticoagulants, cardiac glycosides, and oxygen therapy.

To prevent fat embolism, it is necessary to eliminate factors that could cause lipid particles to enter the blood. In case of fractures, it is important to stop the bleeding as soon as possible, correctly fix the injured limb, monitor the patient’s condition, and control blood pressure.

Prevention and treatment of air embolism

If there are signs of pathology, the patient needs emergency care. He is fitted with a venous catheter for air aspiration and connected to an artificial respiration apparatus. To eliminate tissue hypoxia, oxygen instillations and hyperbaric oxygenation are performed.

To prevent air embolism, scuba divers must strictly follow safety rules when ascending from depth to the surface in order to prevent decompression sickness. The pathology can be caused by air entering an injured blood vessel, so it is important to promptly provide medical care to patients with such injuries and monitor their health.

When injecting drugs into a vein, it is important to follow safety requirements to avoid air bubbles entering the vessel.

Acute arterial thrombosis.

Acute arterial thrombosis extremely rarely develops in healthy arteries.
In more than 90% of cases, it occurs in patients with chronic obliterating diseases of the arteries of atherosclerotic (mainly) origin. More rare causes of thrombosis are: a violation of the blood coagulation system and a slowdown in blood flow. To varying degrees, they are present in patients with chronic obliterating lesions of the arteries. Men get sick more often than women. The peak incidence occurs in the 5th-6th decade of life. The symptoms of the disease are the same as for arterial embolism and depend on the severity of ischemia and the speed of its development. In general, it is believed that the development of ischemia during thrombosis is slower and not as pronounced as during embolism. However, a differential diagnosis cannot be based on these signs. A supporting sign may be previous chronic vascular disease and the absence of embologenic sources (heart disease, aneurysm, etc.). Of the additional examination methods, it is necessary, first of all, to point out angiography, which makes it possible to establish the location and extent of the thrombosed segment, and most importantly, the condition of the arteries located distal to the thrombosis. Angiograms show characteristic signs of chronic obliterating lesions of the arteries: segmental stenoses, corroded (uneven) artery contours, formed collaterals. In embolism, on the contrary, the occlusion border has a characteristic concave surface and ends abruptly, the overlying vessels have smooth walls, and the collaterals are poorly defined.

Treatment.

In acute thrombosis, urgent surgery is indicated only in cases accompanied by severe ischemia that threatens the viability of the limb.
But even in these cases, all efforts should be directed at preliminary clarification of local operability (Dopplerography, angiography). In those patients whose limb ischemia is not severe after thrombosis, it is better to restore blood circulation in a delayed period. During this period, conservative therapy and a comprehensive examination of the patient are carried out.

Conservative treatment.

In some cases, fibrinolytic therapy is used. In this case, thrombus lysis is possible in the early stages by endovascular administration of thrombolytic drugs to the thrombosed segment or systemic administration of thrombolytics.

Surgery:

in case of thrombosis, it cannot be limited to thrombectomy. Reconstructive operations such as bypass surgery, thromboendarterectomy, etc. are required.

Amniotic fluid embolism

Amniotic fluid embolism is a pathological condition in pregnant women. It occurs when amniotic fluid enters the mother's bloodstream. This liquid contains prostaglandins and other components, the effect of which causes an anaphylactoid reaction.

Pathology manifests itself in the following forms:

• swelling of the lung tissue with the development of acute respiratory failure;
• cardiac shock, which is characterized by a thread-like rapid pulse, a sharp decrease in pressure, nausea and vomiting, pallor, bluish skin, loss of consciousness;
• convulsive syndrome, which affects all muscle groups;
• hemorrhagic bleeding from the nose and mouth, vagina;
• multiple organ failure, which manifests itself as a disruption in the functioning of the main organs and systems.

Causes

Amniotic fluid can enter the bloodstream of a pregnant woman if the pressure inside the uterus increases, the pressure in the veins of the uterus decreases, or if the vessels that contact the amniotic sac are damaged.

Risk factors are:

• multiple pregnancy or high fetal weight;
• breech presentation of the fetus;
• polyhydramnios;
• low elasticity of the cervix;
• rapid labor;
• individual anatomical features of the birth canal.

The development of embolism against the background of a decrease in venous pressure can occur in patients with diabetes mellitus, heart defects, and preeclampsia. Women with low vascular tone due to frequent childbirth and patients taking diuretics and antihypertensive drugs are susceptible to pathology.

The entry of amniotic fluid into the blood due to damage to the amniotic sac and vascular injury occurs during placental abruption, careless cesarean section or embryotomy - an operation to remove the fetus through the birth canal in the event of intrauterine death.

Treatment and prevention

In case of amniotic fluid embolism, a woman needs urgent medical care, which is aimed at eliminating the anaphylactoid reaction. First of all, oxygen therapy is used, which consists of connecting the patient to an artificial respiration apparatus and using oxygen instillations. To normalize hemostasis, blood products, blood replacement fluids, and high doses of glucocorticosteroids are used.

If the above measures lead to a positive result, delivery is possible naturally through the birth canal. If there is no improvement, an urgent caesarean section is required. To prevent amniotic fluid embolism, it is important to avoid conditions that can lead to such a pathology. It is important to visit your doctor in a timely manner to monitor the progress of pregnancy and eliminate uterine hypertonicity. In the case of placental insufficiency and other pathological conditions, it is necessary to take timely measures aimed at preventing embolism.

Diagnostics

To diagnose embolism, a comprehensive examination is prescribed: it is important not only to establish an accurate diagnosis, but also to find out the nature and cause of the embolism.

Diagnosis of thromboembolism is based primarily on the use of computed tomography (CT), a method that allows one to determine the presence of a blood clot in the pulmonary vessels. Other diagnostic methods are also used (ventilation-perfusion scintigraphy, venous compression ultrasonography, pulmonary vascular angiography), which are of auxiliary value.

Source: cardiobook.ru

In case of fat embolism, laboratory tests can reveal:

• decreased oxygen content in the blood;
• decreased hemoglobin levels;
• decreased platelet count, decreased fibrinogen levels;
• the presence of neutral fat in urine, blood, sputum, liquor;
• the presence of fatty retinal angiopathy;
• presence of fat on skin biopsy in the area of ​​petechiae.

Instrumental studies (MRI, CT) make it possible to establish the origin of the embolism; chest radiography allows us to exclude or confirm pneumothorax and the presence of acute respiratory distress syndrome. Monitoring using pulse oximetry and control of intracranial pressure are also used.

Diagnosis of air embolism is made using the following methods:

• capnogram - a non-invasive method of measuring and recording carbon dioxide levels during the respiratory cycle;
• blood gas examination reveals external respiration disorders - hypoxemia and hypercapnia;
• transesophageal echocardiography allows you to measure the volume of air entering the systemic circulation and detects atrial septal defect;
• precordial and transesophageal Dopplerography - does not provide information on the amount of air incoming, but is a highly sensitive diagnostic method and allows you to monitor the left and right parts of the heart simultaneously;
• transcranial Doppler sonography - used to assess the speed of blood flow in vessels; it can also diagnose air emboli in the vessels of the brain.

Consequences and complications of amniotic fluid embolism can include acute cerebrovascular accidents, acute renal failure, and death of the mother and fetus.