Occlusion of carotids
Occlusion of carotids — a partial or full obturation of a gleam of carotid arteries, krovosnabzhayushchy a brain. Can have an asymptomatic current, but it is more often shown by repeated TIA, clinic of chronic cerebral ischemia, ischemic strokes in the pool of average and forward brain arteries. Diagnostic search at occlusion of carotids is directed to establishment of the place, genesis and degree of an obturation. It includes UZDG of carotid vessels, a cerebral angiography, a magnetic and resonant angiography, brain KT or MPT. The most effectively surgical treatment consisting in an endarterektomiya, stenting of an affected area of an artery or creation of the roundabout vascular shunt.
Occlusion of carotids
Modern researches in the field of neurology showed that at most of the patients having brain ischemia ekstrakranialny (extra cranial) departments krovosnabzhayushchy a brain of vessels are struck. Intrakranialny (intra cranial) changes of vessels come to light 4 times less often. At the same time occlusion of carotids makes about 56% of cases of cerebral ischemia and causes up to 30% of strokes.
Occlusion of carotids can have partial character when there is only a narrowing of a gleam of a vessel. In such cases the term "stenosis" is more often applied. Full occlusion represents an obturation of all diameter of an artery and at sharp development often leads to developing of an ischemic stroke, and in certain cases — by sudden death.
Anatomy of system of carotids
The left general carotid (GC) begins from an aorta arch, and right — from a brakhiotsefalny trunk. Both of them rise vertically up and in a neck are localized ahead of cross shoots of cervical vertebras. At the level of a thyroid cartilage each WASP is divided into internal (VSA) and external (NSA) carotids. NSA is responsible for blood supply of facial tissues and the head, other estrakranialny structures and a part of a firm brain cover. VSA in a temporal bone passes through the channel in a cavity of a skull and provides intrakranialny blood supply. It feeds a hypophysis, frontal, temporal and parietal shares of a brain of the party of the same name. The eye artery giving blood supply to various structures of an eyeball and eye-socket departs from VSA. In the field of a kavernozny sine of VSA gives a branch, anastomoziruyushchy with a branch of NSA passing to an internal surface of the basis of a skull through an opening of a wedge-shaped bone. On this anastomoz occurs collateral blood circulations at VSA obturation.
Reasons of occlusion of carotids
Atherosclerosis acts as the most often found etiologichesky factor of occlusion of carotid arteries. The atherosclerotic plaque settles down inside on a vascular wall and consists of cholesterol, fats, blood cells (mainly platelets). In process of growth the atherosclerotic plaque can cause full occlusion of a carotid artery. On a surface of a plaque formation of blood clot which with current of blood moves ahead further on the vascular course is possible and to become the reason of thrombosis of intrakranialny vessels. At incomplete occlusion the plaque can come off a vascular wall. Then it turns in , capable to lead to a thrombembolia of cerebral vessels of smaller caliber.
Of carotids also other pathological processes of a vascular wall can call Obturation, for example, at a fibromyshechny dysplasia, Horton's disease, Takayasu's arteritis, a disease moya-moya. Traumatic occlusion of carotid arteries develops as a result of ChMT and is caused by formation of a subintimalny hematoma. Carry hyper coagulative states to other etiofaktor (, crescent and cellular anemia, an anti-phospholipidic syndrome), a gomotsistinuriya, a cardiogenic embolism (at the valvate acquired and congenital heart diseases, a bacterial endocarditis, a myocardial infarction, vibrating arrhythmia with formation of blood clots), tumors.
Act as the factors promoting a stenosis and an obturation of carotid arteries: features of anatomy of these vessels (a hypoplasia, tortuosity, a kinking), diabetes, smoking, improper feeding with the increased content of animal fats in a diet, obesity and so forth.
Symptoms of occlusion of carotids
The clinic of an obturation of carotids depends on localization of defeat, speed of development of occlusion (suddenly or gradually) and extents of development vascular kollateraly, the same sites of a brain providing alternative blood supply. At gradual development of occlusion there is a reorganization of blood supply at the expense of collateral vessels and some adaptation of brain cages to the developed conditions (the lowered intake of nutrients and oxygen); the clinic of chronic ischemia of a brain is formed. Bilateral character of an obturation has heavier current and less favorable forecast. Sudden occlusion of carotid arteries as a rule leads to an ischemic stroke.
In most cases occlusion of carotids demonstrates the tranzitorny ischemic attack (TIA) — passing disorder of cerebral blood circulation which duration, first of all, depends on extent of development vascular the kollateraly struck brain zone. The most typical symptoms of TIA in carotid system are mono - or a hemiparesis and violations of sensitivity on the opposite side (geterolateralno) in combination with monocular disorders of sight on the party of defeat (gomolateralno). Usually as the beginning of the attack serves emergence of a sleep or paresteziya of a half of the face and fingers of a brush, development of muscular weakness in all hand or only in its disteel departments. Visual violations vary from feeling of spots before eyes before considerable decrease in visual acuity. The retina heart attack starting development of an atrophy of an optic nerve is in some cases possible. At an obturation of carotids treat more rare manifestations of TIA: dizartriya, aphasia, front paresis, headache. Certain patients point to dizziness, faintness, swallowing violations, visual hallucinations. In 3% of cases local spasms or big epipristupa are observed.
According to various data the risk of an ischemic stroke within 1 year after emergence of TIA makes from 12 to 25%. Approximately at 1/3 patients the stroke happens to occlusion of carotids after one or several TIA, at 1/3 it develops without the previous TIA. 1/3 more patients at whom the ischemic stroke is not observed make, and TIA continue to occur. The clinical picture of an ischemic stroke is similar to TIA symptoms, however it has an enduring current, i.e. neurologic deficiency (paresis, a gipesteziya, visual frustration) does not pass over time and can will decrease only as a result of timely adequate treatment.
In certain cases manifestations of occlusion have no sharp beginning and are so not expressed that it is very difficult to assume vascular genesis of the arisen problems. The condition of the patient at the same time is often treated as clinic of a cerebral tumor or dementia. Certain authors point that irritability, the depression, confusion of consciousness, a gipersomniya, emotional lability and dementia can develop as a result of occlusion or a microembolism of VSA on the prepotent party or on both sides.
Obturation of the general carotid meets only in 1% of cases. If it develops against the background of normal passability of HCA and BCA, then the collateral blood-groove going through NSA to VSA it appears enough to avoid ischemic damage of a brain. However, as a rule, atherosclerotic changes of carotids have multilevel character that leads to emergence of the occlusion symptoms described above.
The bilateral type of occlusion of carotids at well developed can have a malosimptomny current. But more often it leads to the bilateral strokes of brain hemispheres which are shown a spastic tetraplegiya and a coma.
Diagnostics of occlusion of carotids
In diagnostics, along with neurologic inspection of the patient and studying of data of the anamnesis, tool methods of a research of carotids have fundamental value. UZDG of vessels of the head and a neck belongs to the most available, safe and rather informative method. At occlusion of carotid arteries of UZDG of ekstrakranialny vessels usually reveals the accelerated retrograde blood-groove on superficial branches of NSA. In the conditions of occlusion blood on them moves to an eye artery, and through it to VSA. During UZDG carry out test with a sdavleniye of one of superficial branches of NSA (more often than a temporal artery). Reduction of a blood-groove on an eye artery at a manual sdavleniye of a temporal artery indicates VSA occlusion.
The angiography of cerebral vessels allows to determine the level of occlusion of carotids precisely. However because of danger of complications it can be carried out only in difficult diagnostic cases or just before implementation of surgical treatment. MRA — a magnetic and resonant angiography became excellent and safe replacement of an angiography. Today in many clinics of MRA in combination with MRT of a brain are "the gold standard" of diagnostics of occlusion of carotids.
Ischemic defeat of cerebral structures is visualized by means of brain MPT or KT. At the same time existence of "white" ischemia indicates gradual atherosclerotic character of an obturation of carotid arteries, and ischemia with hemorrhagic treatment — embolichesky type of defeat. It is also necessary to consider that approximately at 30% of patients with an ischemic stroke in the first days focal changes in tissues of a brain are not visualized.
Treatment of occlusion of carotids
Concerning occlusion of carotids application of various surgical tactics which choice depends on a look, level and degree of an obturation, a condition of collateral blood circulation is possible. In cases when operation is carried out later 6-8ch from the beginning of the progressing ischemic stroke, the lethality of patients reaches 40%. In this regard expeditious treatment is expedient before development of a stroke and has preventive value. As a rule, it is carried out in intervals between TIA at stabilization of a condition of the patient. Surgical treatment is performed mainly at ekstrakranialny type of occlusion.
Among indications to surgical treatment there is a stenozirovaniye and obturation of carotid arteries allocate: recently postponed TIA, an ended ischemic stroke with the minimum neurologic violations, asymptomatic occlusion of the cervical site of VSA more than 70%, existence of sources of an embolism in ekstrakranialny arteries, a syndrome of insufficient arterial blood supply of a brain.
At partial occlusion of carotids operations of the choice are: stenting and carotid endarterektomiya (eversionny or classical). The full obturation of a vascular gleam is the indication for creation extra- an anastomoza — a new way of blood supply, bypassing the okklyuzirovanny site. At safety of a gleam of VSA subclavial and all-sleepy prosthetics is recommended, at its obturation — subclavial prosthetics.
Forecast and prevention
According to the generalized data asymptomatic partial occlusion of carotid arteries to 60% in 11 cases from 100 is followed by development of a stroke within 5 years. When narrowing a gleam of an artery to 75% risk of an ischemic stroke — 5,5% a year. At 40% of patients with full occlusion of VSA the ischemic stroke develops in the first year of its emergence. Performing preventive surgical treatment allows to minimize risk of development of ONMK.
The actions directed to prevention of arterial occlusion include disposal of addictions, healthy nutrition, fight against excess weight, correction of a lipidic profile of blood, timely treatment of cardiovascular diseases, vaskulit and hereditary pathology (for example, various koagulopatiya).