Koarktation of an aorta – a congenital segmentary stenosis (or a full atresia) aortas in the field of an isthmus - transition of an arch to the descending part; more rare – in the descending, ascending or belly departments. Koarktation of an aorta is shown at children's age by concern, cough, cyanosis, short wind, a hypotrophy, fatigue, dizziness, heartbeat, nasal bleedings. At diagnostics of a koarktation of an aorta data of the ECG, a X-ray analysis of a thorax, EhoKG, sounding of cavities of heart, the ascending aortografiya, the left ventrikulografiya, a coronary angiography are considered. As methods of surgical treatment of a koarktation of an aorta serve translyuminalny balloon dilatation, an istmoplastika (direct and indirect), an aorta koarktation resection, shunting.
Koarktation of an aorta
Koarktation of an aorta – the congenital anomaly of an aorta which is characterized by its stenosis, as a rule, in the typical place - distalny the left subclavial artery, in the place of transition of an arch to the descending aorta. In children's cardiology the koarktation of an aorta meets frequency of 7,5%, at the same time is 2 — 2,5 times more often at males. In 60-70% of cases the koarktation of an aorta is combined with other congenital heart diseases: an open arterial channel (70%), defect of an interventricular partition (53%), an aorta stenosis (14%), a stenosis or insufficiency of the mitralny valve (3-5%), is more rare with a transposition of the main vessels. At a part of newborns from a koarktatsiy aorta heavy ekstrakardialny congenital anomalies of development come to light.
Aorta koarktation reasons
In a heart surgery several theories of formation of a koarktation of an aorta are considered. It is considered to be that violation of merge of aortal arches in the embryogenesis period is the cornerstone of defect. According to the theory of Skoda, a koarktation of an aorta it is formed owing to closing of the open arterial channel (OAC) with simultaneous involvement of an adjacent part of an aorta. The obliteration of Batallov Canal occurs soon after the birth; at the same time walls of a channel are fallen down and cicatrize. When involving in this process of a wall of an aorta there is its narrowing or a full zarashcheniye of a gleam on a certain site.
According to Anderson-Becker's theory existence of a crescent ligament of aorta which causes narrowing of an isthmus at OAP obliteration in the field of its arrangement can serve as the reason of a koarktation.
According to the haemo dynamic theory of Rudolf, an aorta koarktation – a consequence of features of pre-natal blood circulation of a fruit. During pre-natal development through the ascending aorta there pass 50% of emission of blood from ventricles, through descending - 65%, at the same time only 25% of blood come to an isthmus of an aorta. The relative narrowness of an isthmus of an aorta which under some conditions (with septalny defects) remains and aggravated after the child's birth is connected with this fact.
Features of haemo dynamics at an aorta koarktation
As the typical location of a stenosis serves the terminal department of an arch of an aorta between an arterial channel and the mouth of the left subclavial artery (area of an isthmus of an aorta). In this place the koarktation of an aorta comes to light at 90-98% of patients. Outside narrowing can have an appearance of hourglasses or a banner with a normal diameter of an aorta in proximal and disteel departments. External narrowing, as a rule, does not correspond to the size of internal diameter of an aorta as in a gleam of an aorta the hanging crescent fold or a diaphragm which in certain cases completely block an internal gleam of a vessel settles down. Extent of a koarktation of an aorta can make from several mm to 10 and more than a cm, however is more often limited to 1-2 cm.
Stenotichesky change of an aorta in the place of transition of its arch to the descending part causes development of two modes of blood circulation in a big circle: proksimalny places of an obstacle to a blood-groove there is arterial hypertension, distalny – hypotension. Due to the available haemo dynamic violations at patients from a koarktatsiy aorta compensatory mechanisms turn on – the hypertrophy of a myocardium of the left ventricle develops, shock and minute volume increases, diameter of the ascending aorta and branches of its arch extends, the network of kollateraly rasyoshiryatsya. At children 10 years in an aorta and vessels are more senior atherosclerotic changes are already noted.
On features of haemo dynamics at an aorta koarktation considerable impact is exerted by the accompanying congenital heart diseases and vessels. Over time in the arteries involved in collateral blood circulation (intercostal, internal chest, side chest, scapular, epigastralny, etc.), there are changes: their walls become thinner, and diameter increases, contributing to formation of prestenotichesky and poststenotichesky aneurisms of an aorta, aneurisms of arteries of a brain, etc. Usually anevrizmatichesky expansion of vessels is observed at patients 20 years are more senior.
Pressure of wavy and expanded intercostal arteries upon edges promotes education (jags) at bottom edges of edges. These changes appear at patients from a koarktatsiy aorta aged 15 years are more senior.
Classification of a koarktation of an aorta
Taking into account localization of pathological narrowing distinguish a koarktation in the field of an isthmus, the ascending, descending, chest, belly aorta. Some sources allocate the following anatomic options of defect - a preduktalny stenosis (narrowing of an aorta proksimalny OAP confluences) and a postduktalny stenosis (narrowing of an aorta distaltny OAP confluences).
A. V. Pokrovsky classifies 3 types of a koarktation of an aorta by criterion of plurality of anomalies of heart and vessels:
- 1 type - the isolated aorta koarktation (73%);
- 2 type – an aorta koarktation combination to OAP; with arterial or venous dumping of blood (5%);
- 3 type – an aorta koarktation combination to others of a gemodinamicheska significant anomalies of vessels and VPS (12%).
In the natural course of a koarktation of an aorta allocate 5 periods:
- I (the critical period) - at children till 1 year; it is characterized by symptoms of insufficiency of blood circulation on a small circle; high a heavy warm and pulmonary and renal failure mortality, especially at an aorta koarktation combination to other VPS.
- II (the adaptive period) - at children from 1 to 5 years; it is characterized by reduction of symptomatology of insufficiency of blood circulation which is usually presented by increased fatigue and short wind.
- III (the compensatory period) – at children are from 5 to 15 years; it is characterized by mainly asymptomatic current.
- IV (the period of development of a relative decompensation) – at patients are 15-20 years; in the period of puberty signs of insufficiency of blood circulation accrue.
- V (the decompensation period) – at patients are 20-40 years; it is characterized by symptoms of arterial hypertension, heavy left-and right ventricular heart failure, a high lethality.
Aorta koarktation symptoms
The clinical picture of a koarktation of an aorta is presented by a set of symptoms; manifestations and their expressiveness depend on the period of a course of defect and the accompanying anomalies influencing intracardial and system haemo dynamics. At children of early age from a koarktatsiy aorta the growth inhibition and increases in body weight can be noted. Symptoms of left ventricular insufficiency prevail: , short wind, cardiac asthma, hypostasis of lungs.
At more advanced age, in connection with development of pulmonary hypertensia, complaints to dizziness, headache, heartbeat, noise in ears, decrease in visual acuity are characteristic. At a koarktation of an aorta nasal bleedings, faints, a blood spitting, feeling of a sleep and chill, the alternating lameness, spasms in the lower extremities, the abdominal pains caused by intestines ischemia are frequent.
Average life expectancy of patients from a koarktatsiy aorta makes 30-35 years, about 40% of patients die in the critical period (age till 1 year). As the most frequent reasons of a lethal outcome in the period of a decompensation serve heart failure, a septic endocarditis, ruptures of aneurisms of an aorta, a hemorrhagic stroke.
Diagnostics of a koarktation of an aorta
At survey existence of athletic type of a constitution (primary development of a humeral belt pays attention at thin lower extremities); strengthening of a pulsation of sleepy and intercostal arteries, easing or lack of a pulsation on femoral arteries; raised HELL on the top extremities at decrease HELL on the lower extremities; systolic noise over a top and the basis of heart, on carotids etc.
In diagnostics of a koarktation of an aorta the crucial role is played by tool researches: The ECG, EhoKG, an aortografiya, a X-ray analysis of a thorax and a X-ray analysis of heart with contrasting of a gullet, sounding of cavities of heart, a ventrikulografiya, etc.
Electrocardiographic data testify for an overload and a hypertrophy of the left and/or right departments of heart, ischemic changes of a myocardium. The radiological picture is characterized by a kardiomegaliya, a vybukhaniye of an arch of a pulmonary artery, change of a configuration of a shadow of an arch of an aorta, uzuratsiy edges.
The echocardiography allows to visualize directly a koarktation of an aorta and to define stenosis degree. To children of advanced age and adults chrespishchevodny EhoKG can be carried out.
At a kateterization of cavities of heart prestenotichesky hypertensia and poststenotichesky hypotension, decrease in partial pressure of oxygen in poststenotichesky department of an aorta is defined. By means of the ascending aortografiya and the left ventrikulografiya the stenosis is found, its degree and anatomic option is estimated. Coronary angiography at a koarktation of an aorta is shown in case of existence of episodes of stenocardia, and also when planning operation to patients 40 years for IBS exception are more senior.
Koarktatsy should differentiate aortas from other pathological states proceeding with the phenomena of pulmonary hypertensia: vazorenalny and essentsialny arterial hypertension, aortal heart disease, nonspecific aortit (Takayasu's disease).
Treatment of a koarktation of an aorta
At a koarktation of an aorta there is a need for medicamentous prevention of an infectious endocarditis, correction of arterial hypertension and heart failure. Elimination of anatomic defect of an aorta is carried out only by an operational way.
Cardiac operation for a koarktation of an aorta is carried out in early terms (at critical defect - till 1 year, in other cases aged from 1 up to 3 years). As contraindications to surgical treatment of a koarktation of an aorta serve irreversible degree of pulmonary hypertensia, existence of the heavy or nekorrigiruyemy accompanying pathology, a terminal stage of heart failure.
For treatment of a koarktation of an aorta it is offered the following types of open operations now:
- I. Local and plastic reconstruction of an aorta: a resection of the stenozirovanny site of an aorta with imposing of an anastomoz "the end in the end"; a direct istmoplastika with a longitudinal section of a stenosis and sewing together of an aorta in the cross direction; an indirect istmoplastika (with use of a rag from the left subclavial artery or a synthetic patch, with imposing of a sleepy and subclavial anastomoz).
- II. An aorta koarktation resection with prosthetics: with defect replacement with an arterial gomotransplantat or a synthetic artificial limb.
- III. Creation of roundabout anastomoz: roundabout shunting with use of the left subclavial artery, splenic artery or a corrugated vascular artificial limb.
At a local or tandem stenosis and lack of the expressed kaltsinoz and fibrosis in the field of a koarktation translyuminalny balloon dilatation of an aorta is carried out. Postoperative complications can include development of a rekoarktation of an aorta, aneurism, bleeding; ruptures of anastomoz, thromboses of the reconstructed sites of an aorta; ischemia of a spinal cord, ischemic gangrene of the left top extremity, etc.
Forecast of a koarktation of an aorta
The natural course of a koarktation of an aorta is defined by option of narrowing of an aorta, existence of other VPS and in general has extremely adverse forecast. In the absence of the cardiac help of 40-55% of patients perishes on the first year of life. At timely surgical treatment of a koarktation of an aorta the good remote results manage to be achieved at 80-95% of patients, especially if operation is performed aged up to 10 years.
The operated patients about koarktatsy aortas for life are under observation of the cardiologist and heart surgeon; restriction of physical activity and loadings, regular dynamic surveys for an exception of postoperative complications is recommended to them. The result of pregnancy after reconstructive operations for an aorta koarktation usually favorable. In the course of conducting pregnancy for prevention of a rupture of an aorta hypotensive means are appointed, prevention of an infectious endocarditis is carried out.