The common arterial trunk in the fetus on ultrasound. Causes of the common arterial trunk
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 arterial trunk (persistent truncus arteriosus). The first description of vice belongs to A . Buchanan (1864). This defect accounts for 3.9% of all CHD according to the results of post-mortem studies [McNamara J. J ., Gross R . E ., 1969] and 0.8 - 1.7% - according to clinical data [ Gasul V. M. et at ., 1966; Kidd W., 1978].
Anatomy, - classification. Anatomical criteria common arterial trunk are: the departure from the base of the heart of one vessel, providing systemic, coronary and pulmonary blood supply; pulmonary arteries depart from the ascending part of the trunk; there is a single valve stem ring. The term pseudotruncus refers to an anomaly in which the pulmonary artery is either atretic and presents with fibrous bundles. R. W. Collette and J. E. Edwards (1949) distinguish 4 types of the common arterial trunk (Fig. 65): 1 - a single trunk pulmonary artery and ascending depart from common trunk, right and left pulmonary arteries - from a short pulmonary trunk; II - the left and right pulmonary arteries are located side by side and each depart from rear wall truncus; Ш - departure of the right, left or both pulmonary arteries from the side walls of the trunk; 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 originate from the truncus. Thus, we can talk mainly about two types of defects: I and II - III.
With type I 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: the absence of the right or left branch, stenosis of the mouth of the common trunk. In variant II, the dimensions of the pulmonary arteries are equal and amount to 2–8 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) first described a valve with a single commissure in a common truncus arteriosus, which, as in aortic stenosis, creates a stenotic hemodynamic effect. The leaflets can be normal, thickened (22%) (small nodules, myxomatous changes are visible along the edge), display - tic (50 %). This structure of the valves predisposes to valvular insufficiency. With age, the deformation of the valves increases, in older children, the development of calculus is possible.
cynosis. The leaflets of the valve of the common trunk are fibrously associated with the mitral valve, so it is considered to be mainly aortic.
The location of the truncus above the ventricles is important in the selection of patients for radical correction of the defect. In the observations of F. Butto et al. (1986) in 42% it was located in equally over both ventricles, in 42% - mainly over the right and in 16% - mainly 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 discharge of the trunk from the right ventricle occurs in 80% of cases, while the closure of the VSD during surgery leads to subaortic obstruction.
VSD is always present at the common arterial trunk, it does not have an upper edge, lies directly under the valves and merges with the mouth of the trunk, there is no infundibular septum.
This defect is often combined with anomalies of the aortic arch: interruption, atresia, right arch, vascular ring, coarctation.
Other concomitant UPUs are open general at -
rioventricular canal, single ventricle, single pulmonary artery, anomalous pulmonary venous drainage. Of the extra-cardiac defects, there are anomalies of the gastrointestinal tract, urogenital and skeletal anomalies.
Common arterial trunk - CHD, in which one large vessel departs 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 arterial trunk (persistent truncus arteriosus). The first description of vice belongs to A. Buchanan (1864). This defect accounts for 3.9% of all CHD according to the results of pathoanatomical studies and 0.8-
- 7% - according to clinical data.
- - origin of the right, left or both pulmonary arteries from the side walls of the trunk; 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 originate from the truncus. Thus, we can talk mainly about two types of defects: I and II-III.
cynosis. The leaflets of the valve of the common trunk are fibrously associated with the mitral valve, so it is considered to be mainly aortic.
The location of the truncus above the ventricles is important in the selection of 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 discharge of the trunk from the right ventricle occurs in 80% of cases, while the closure of the VSD during surgery leads to subaortic obstruction.
VSD is always present at the common arterial trunk, it does not have an upper edge, lies directly under the valves and merges with the mouth of the trunk, there is no infundibular septum.
This defect is often combined with anomalies of the aortic arch: interruption, atresia, right arch, vascular ring, coarctation.
Other concomitant UPUs are open general atm.
rioventricular canal, single ventricle, single pulmonary artery, anomalous pulmonary venous drainage. Of the extracardiac malformations, 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, trunk and branches of the pulmonary artery is equal, which explains early development pulmonary hypertension; the exception is cases with stenosis of the mouth of the pulmonary artery and its branches or their small diameter. The right ventricle, with a common arterial trunk, overcomes systemic resistance, which causes hypertrophy of its myocardium, dilatation of the cavity. The hemodynamic features of the defect are largely determined by the state of circulation in the pulmonary circulation. The following options can be distinguished.
- Increased pulmonary blood flow with low resistance in the vessels of the lung, the pressure in the pulmonary arteries is equal to the systemic one, which indicates high pulmonary hypertension. It is more common in young children, accompanied by heart failure resistant to therapy. cyanosis may not be a large number of blood is oxygenated in the lungs and mixed in the ventricles due to big size VSD. A large discharge into the common trunk, especially with a multi-leaf valve, contributes to the appearance of valvular insufficiency over time, which further exacerbates the severity clinical course diseases.
- Normal or slightly increased pulmonary blood flow due to new resistance in the vessels of the small circle, preventing a large discharge of blood into the common trunk. There is no heart failure, cyanosis appears during exercise.
- Reduced pulmonary blood flow (hypovolemia) may occur when the mouth of the trunk or branches of the pulmonary artery narrows or with progressive sclerosis of the pulmonary vessels. Severe cyanosis is constantly noted, as 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 sign should be considered shortness of breath by the type of tachypnea up to 50-100 per minute. In cases of reduced pulmonary blood flow shortness of breath is much less pronounced. Cyanosis in the common arterial trunk is different: 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, it
driven by the development of symptoms of "watch glasses" and " drumsticks", iolicythemia. With cardiomegaly, a heart hump appears. The heart sounds are loud, the II tone above the pulmonary artery is accentuated, it can be single and split in the presence of more than three valves. An apical systolic click is often determined. A rough, prolonged VSD murmur is determined in the third and fourth intercostal spaces on the left side of 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 leaflets causes a stenotic effect in the second and third intercostal spaces, the left or right is auscultated systolic murmur type of exile. With the development of insufficiency of the trunk valves along the left edge of the sternum, a protodiastolic murmur appears. Heart failure is expressed according to the right and left ventricular type up to the picture pulmonary edema; it is less or absent in hypovolemia of the pulmonary circulation and sclerotic changes in the pulmonary vessels.
There are no specific electrocardiographic characteristics of the defect. Electric axle the heart is located normally or deviated to the right (from - (-60 to 4-120 °). Half of the patients have increased right atrium, right ventricle (in assignment QRS complex type R or qR), less often both ventricles. With pulmonary hypertension, the ECG shows signs of "strain" type overload in the right chest leads (decrease in the ST interval by 0.3-0.8 cm, negative T waves in the leads
Vi-h).
On the FCG, the usual amplitude of the tone at the apex is visible, in the second intercostal space aortic clicks are fixed; II 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 enhanced, with stenosis of the mouth of the pulmonary artery it is depleted on both sides, with stenosis or atresia of one of the branches - on one, with a sclerotic phase of pulmonary hypertension - it is depleted mainly along the periphery and enhanced in the root zone. The heart is often moderately enlarged (cardiothoracic ratio - from 52 to 80%), may become ovoid with a narrow vascular bundle, which resembles a transposition main vessels, but with a straighter top left edge. Both ventricles are usually enlarged. Sometimes the heart is similar in shape to that of Fallot's tetrad, 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 one-third of patients, which, combined with increased pulmonary blood flow and cyanosis, should raise suspicion of a common arterial trunk.
Nostic value may have a high position of the left pulmonary artery.
A characteristic M-echocardiographic sign of the defect is the absence of a continuous septal-aortic (anterior) continuation, while the wide vessel "sits on top" of the VSD. With a predominant departure of the common trunk from the left ventricle, the posterior (mitral-lunate) continuation is preserved. When the arterial trunk communicates mainly with the right ventricle, a violation of the anterior and posterior continuous continuations is recorded. Other M-echocardiographic signs of defect are: the 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 arterial trunk; dilatation of the left atrium.
A two-dimensional echocardiographic examination in the projection of the long axis of the left ventricle reveals a wide main vessel that crosses the ("top sitting") 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 place of origin of the pulmonary artery or its branches from the trunk.
Cardiac catheterization 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 DMZHP. Further, the catheter is freely passed into the truncus, where the pressure is the same as in the ventricles. The saturation of blood with oxygen in the common arterial trunk 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. With the introduction contrast agent into the right ventricle is visible (preferably in lateral projection) the common arterial trunk, from which 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 truncus valve insufficiency (Fig. 66).
Differential Diagnosis should be performed in cases without cyanosis with VSD, with cyanosis - with Fallot's tetrad (especially with pulmonary artery atresia), transposition of the great vessels, Eisenmenger's 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; in 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 of them survive the first year, and 10% survive until the 1-3rd decade)
