Common truncus arteriosus in the fetus on ultrasound. Causes of the common arterial truncus
General truncus arteriosus- In PS, in which one large vessel departs from the base of the heart through a single semilunar valve and provides coronary, pulmonary and systemic circulation [Bankl H., 1980]. Other names: common trunk, common aortopulmonary trunk, persistent truncus arteriosus. The first description of the vice belongs to A. Buchanan (1864). This defect accounts for 3.9% of all congenital heart defects according to the results of pathological studies [McNamara J. J., Gross R. E., 1969] and 0.8 - 1.7% - according to clinical data [Gasul V. M. et at., 1966; Kidd V., 1978].
Anatomy - classification. Anatomical criteria the common arterial trunk are: the departure from the base of the heart of one vessel, providing systemic, coronary and pulmonary blood supply; the pulmonary arteries arise from the ascending trunk; there is a single barrel valve ring. The term pseudotruncus refers to anomalies in which the pulmonary artery is either atretic and consists of fibrous bundles. R. W. Collett and J. E. Edwards (1949) distinguish 4 types of common arterial trunk (Fig. 65): 1 - single trunk pulmonary artery and the ascending one departs from common trunk, right and left pulmonary arteries - from the short pulmonary trunk; II - the left and right pulmonary arteries are located nearby and each depart from back wall truncus; Ш - origin of the right, left or both pulmonary arteries from the lateral walls of the truncus; IV - the absence of pulmonary arteries, due to which the blood supply to the lungs is carried out through the bronchial arteries extending from the descending aorta. This variant is not currently recognized as a type of true truncus arteriosus, in which at least one branch of the pulmonary artery must arise from the truncus. Thus, we can talk mainly about two types of defects: I and II - III.
With type I of the common arterial trunk, the length of the common trunk of the pulmonary artery is 0.4 - 2 cm. Anomalies in the development of the pulmonary artery are possible: absence of the right or left branch, stenosis of the mouth of the common trunk. In option II, the sizes of the pulmonary arteries are equal and range from 2 to 8 mm, sometimes one is smaller than the other. The valve of the common arterial trunk can be one - (4%), two - (32 %), three - (49%) and four-leaf (15 %). F. Butto et al. (1986) were the first to describe a valve with one commissure in the common truncus arteriosus, which, as in aortic stenosis, creates a stenotic hemodynamic effect. The valves can be normal, thickened (22%) (small nodules and myxomatous changes are visible along the edges), display-like (50 %). This structure of the valves predisposes to valve insufficiency. With age, the deformation of the valves increases; in older children, cal -
cinosis. The valve leaflets of the common trunk are fibrously connected to the mitral valve, so it is considered to be primarily aortic.
The location of the truncus above the ventricles is important when selecting patients for radical correction of the defect. In observations of F. Butto et al. (1986) in 42% it was located in equally over both ventricles, in 42% - predominantly over the right and in 16% - predominantly over the left ventricle. In these cases, the exit from the ventricle, which is not connected to the trunk, is the VSD. According to other observations, the truncus departs from the right ventricle in 80% of cases, while closure of the VSD during surgery leads to subaortic obstruction.
A VSD is always present with the common truncus arteriosus; it does not have an upper edge, lies directly under the valves and merges with the mouth of the truncus; there is no infundibular septum.
This defect is often combined with anomalies of the aortic arch: break, atresia, right-sided arch, vascular ring, coarctation.
Other accompanying congenital disorders are open general at -
rioventricular canal, single ventricle, single pulmonary artery, anomalous drainage of the pulmonary veins. Extra cardiac defects include anomalies of the gastrointestinal tract, urogenital and skeletal anomalies.
Common truncus arteriosus - congenital heart disease, in which one large vessel arises from the base of the heart through a single semilunar valve and provides coronary, pulmonary and systemic circulation. Other names: common trunk, common aortopulmonary trunk, persistent truncus arteriosus. The first description of the vice belongs to A. Buchanan (1864). This defect accounts for 3.9% of all congenital heart defects according to the results of pathological studies and 0.8-
- 7% - according to clinical data.
- - origin of the right, left or both pulmonary arteries from the lateral walls of the truncus; IV - absence of pulmonary arteries, due to which the blood supply to the lungs is carried out through the bronchial arteries arising from the descending aorta. This variant is not currently recognized as a type of true truncus arteriosus, in which at least one branch of the pulmonary artery must arise from the truncus. Thus, we can talk mainly about two types of defects: I and II-III.
cinosis. The valve leaflets of the common trunk are fibrously connected to the mitral valve, so it is considered to be primarily aortic.
The location of the truncus above the ventricles is important when selecting patients for radical correction of the defect. In the observations of F. Butto et al (1986), in 42% it was located equally above both ventricles, in 42% - predominantly above the right and 16% - predominantly above the left ventricle. In these cases, the exit from the ventricle, which is not connected to the trunk, is the VSD. According to other observations, the truncus departs from the right ventricle in 80% of cases, while closure of the VSD during surgery leads to subaortic obstruction.
A VSD is always present with the common truncus arteriosus; it does not have an upper edge, lies directly under the valves and merges with the mouth of the truncus; there is no infundibular septum.
This defect is often combined with anomalies of the aortic arch: break, atresia, right-sided arch, vascular ring, coarctation.
Other concomitant CHDs include open general at
rioventricular canal, single ventricle, single pulmonary artery, anomalous drainage of the pulmonary veins. Of the extracardiac defects, there are anomalies of the gastrointestinal intestinal tract, urogenital and skeletal anomalies.
Hemodynamics. Blood from the right and left ventricles enters a single vessel through the VSD; the pressure in both ventricles, truncus and branches of the pulmonary artery is equal, which explains early development pulmonary hypertension; The exception is cases with stenosis of the pulmonary artery orifice and its branches or their small diameter. The right ventricle, with the common truncus arteriosus, overcomes systemic resistance, which causes hypertrophy of its myocardium and dilatation of the cavity. The hemodynamic features of the defect are determined largely by the state of blood circulation in the pulmonary circle. The following options can be distinguished.
- Increased pulmonary blood flow with low resistance in the pulmonary vessels, pressure in the pulmonary arteries is equal to systemic pressure, which indicates high pulmonary hypertension. It is more common in young children and is accompanied by heart failure that is resistant to therapy. Cyanosis may not be present because large number blood is oxygenated in the lungs and mixed in the ventricles due to large size VSD. Large discharge into the common trunk, especially with a multi-leaf valve, contributes to the appearance of valvular insufficiency over time, which further aggravates the severity clinical course diseases.
- Normal or slightly increased pulmonary blood flow due to new resistance in the pulmonary vessels, preventing a large discharge of blood into the common trunk. There is no heart failure; cyanosis appears with exercise.
- Reduced pulmonary blood flow (hypovolemia) can occur with narrowing of the mouth of the trunk or branches of the pulmonary artery or with progressive sclerosis of the pulmonary vessels. Severe cyanosis is constantly observed, since a small part of the blood is oxygenated in the lungs.
Clinic, diagnostics. By clinical manifestations children with this defect resemble patients with a large VSD. The leading symptom should be considered shortness of breath of the tachypnea type up to 50-100 per minute. In cases of reduced pulmonary blood flow shortness of breath is significantly less pronounced. Cyanosis in the common truncus arteriosus varies: it is minimal or absent with increased pulmonary blood flow, expressed with sclerotic changes in the pulmonary vessels (Eisenmenger reaction) or pulmonary artery stenosis. In the latter cases, he supported
is driven by the development of symptoms of “watch glasses” and “ drumsticks", iolicythemia. With cardiomegaly, a heart hump appears. Heart sounds are loud, the second heart sound above the pulmonary artery is accentuated, can be single or split if there are more than three valves. An apical systolic click is often detected. A rough, continuous noise of VSD is determined in the third and fourth intercostal spaces on the left near the sternum; there may be meso at the apex diastolic murmur relative stenosis mitral valve- a sign of hypervolemia of the pulmonary circulation. If the structure of the valves causes a stenotic effect in the second and third intercostal spaces, auscultation is heard on the left or right systolic murmur type of exile. With the development of trunk valve insufficiency, a protodiastolic murmur appears along the left edge of the sternum. Heart failure is expressed in the right and left ventricular type, up to the picture pulmonary edema; it is less or absent with hypovolemia of the pulmonary circulation and sclerotic changes in the pulmonary vessels.
There are no specific electrocardiographic characteristics of the defect. Electric axis the heart is located normally or deviated to the right (from -(-60 to 4-120°). In half of the patients, enlarged right atrium, right ventricle (in the lead QRS complex type R or qR), less often both ventricles. With pulmonary hypertension, the ECG shows signs of “strain” type overload in the right precordial leads (decrease in the ST interval by 0.3-0.8 cm, negative T waves in the leads
Vi-z).
On FCG, tones of normal amplitude are visible at the apex, aortic clicks are recorded in the second intercostal space; The second tone is often single, but can be wide and consist of several high-amplitude components; A pansystolic murmur is recorded, sometimes high-frequency with a maximum in the third and fourth intercostal spaces on the left, and a protodiastolic murmur is a sign of valvular insufficiency.
On a chest x-ray, the pulmonary pattern is usually strengthened, with stenosis of the pulmonary artery mouth it is depleted on both sides, with stenosis or atresia of one of the branches - on one side, with the sclerotic phase of pulmonary hypertension - it is depleted mainly along the periphery and strengthened in the hilar zone. The heart is often moderately enlarged (cardiothoracic ratio - from 52 to 80%), may become ovoid with a narrow vascular bundle, which resembles transposition great vessels, but with a straighter upper left edge. As a rule, both ventricles are enlarged. Sometimes the heart is similar in shape to that of tetralogy of Fallot, there is a characteristic wide base of the vessel with an S-shaped course. The right-sided location of the aortic arch is found in 3 patients, which, in combination with increased pulmonary blood flow and cyanosis, should raise suspicion of a common arterial trunk. A certain diagnosis
the high position of the left pulmonary artery may have a nostic significance.
A characteristic M-echocardiographic sign of the defect is the absence of a continuous septal-aortic (anterior) continuation, while a wide vessel “sits astride” the VSD. With the predominant departure of the common trunk from the left ventricle, the posterior (mitral-lunar) continuation is preserved. When the arterial trunk communicates predominantly with the right ventricle, a violation of the anterior and posterior continuous continuations is recorded. Other M-echocardiographic signs of the defect are: inability to determine the second semilunar valve; diastolic flutter of the anterior leaflet of the mitral valve due to insufficiency of the semilunar valve of the common truncus arteriosus; dilatation of the left atrium.
A two-dimensional echocardiographic examination in the long axis projection of the left ventricle reveals a wide great vessel crossing (“ridden”) the septum, a large VSD, the posterior continuation is preserved. In a short projection at the level of the base of the heart, the ventricular outflow tract and the pulmonary valve are not identified. From the suprasternal approach, in some cases, it is possible to determine the origin of the pulmonary artery or its branches from the truncus.
Catheterization of the cardiac cavities and angiocardiography have crucial in diagnostics. Venous catheter enters the right ventricle, where the pressure is equal to the systemic one, but in combination with an increase in blood oxygen saturation indicates
about VSD. Next, the catheter is freely passed into the truncus, where the pressure is the same as in the ventricles. Blood oxygen saturation in the common arterial truncus usually ranges from 90-96% in cases with hypervolemia. The difference in oxygen saturation of the blood of the pulmonary artery and truncus does not exceed 10%. A decrease in blood oxygen saturation to 80% indicates sclerotic changes in the pulmonary vessels and inoperability of patients. When inserted contrast agent in the right ventricle the common arterial trunk is visible (better in the lateral projection), from which the coronary vessels and the pulmonary artery (or its branches). Aortography allows you to finally confirm the origin of the true pulmonary arteries directly from the trunk, detail the type of defect and determine the degree of insufficiency of the truncus valve (Fig. 66).
Differential diagnosis should be carried out in cases without cyanosis with VSD, in cases of cyanosis - with tetralogy of Fallot (especially in pulmonary atresia), transposition of the great vessels, Eisenmenger syndrome.
Course, treatment. The course of the defect is severe from the first days of the patient’s life due to severe heart failure and
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pulmonary hypervolemia; with cyanosis, the severity of the patient's condition is determined by the degree of hypoxemia. Most children die in the first months of life and only "/5 survive the first year, and 10% survive until the 1st-3rd decade)
