Pulmonary atresia, types, prognosis in newborns. pulmonary atresia with ventricular septal defect

Pulmonary atresia is characterized by the absence of direct communication between the right ventricle and the pulmonary arterial bed as a result of the complete congenital absence of an orifice at the level of the right ventricular outlet, pulmonary valve, right and left pulmonary arteries. When combined with VSD, this pathology is often covered in the literature as an "extreme form" of Fallot's tetrad or a "false" common arterial trunk [Litman I., Fono R., 1954; Yonash V., 1963].

History reference.

Due to the fact that one main vessel departs from the heart, long time pulmonary artery atresia with VSD was considered as one of the forms of OSA. However, the works of A. V. Ivanitsky (1977), J. Somerville (1970), performed at a high methodological level, convincingly showed that type IV of the common arterial trunk, according to the classification of R. Collett and J. Edwards (1949), is nothing more than , as atresia of the pulmonary trunk, combined with defects such as tetralogy of Fallot, as well as with one of the forms of TMS. Consequently, this group defects is an independent nosological unit.

Frequency.

Pulmonary artery atresia in combination with VSD is detected in 1-3% of all CHD cases.

The first successful radical operation for this defect was performed by J. Kirklin in 1965. To connect the right ventricle to the pulmonary arteries, the surgeon used an autopericardial tube made on the operating table. In our country, with atresia of the pulmonary trunk with hypoplasia of the pulmonary arteries, the first successful operation to connect the right ventricle with the pulmonary arteries using a tube from the autopericardium without closing the VSD, it was performed by V.P. Podzolkov in 1984.

Etiology and pathogenesis.

Pulmonary atresia in combination with VSD refers to conotruncus malformations. The pulmonary arterial bed consists of 3 main segments of different embryonic origin: 1) the pulmonary trunk is formed as a result of division of the common arterial trunk; 2) the right and left pulmonary arteries are formed from the 6th pair of aortic arches and 3) intrapulmonary arterial vessels from the rudiments of the lungs. The absence or disruption of the development of one or more segments explains the variety of anatomical variants of the defect. In connection with the violation of the development of the arterial cone, there is no fusion of the arterial and interventricular septa, which leads to the formation of VSD.

Classification.

Most common in clinical practice received two classifications. According to the classification of J. Somerville (1970), based on the degree of preservation of the pulmonary arteries, there are 4 types of defect: 1) atresia of the pulmonary valve (the pulmonary trunk, right and left pulmonary arteries are preserved); 2) atresia of the pulmonary valve and pulmonary trunk (the right and left pulmonary arteries are preserved, which can be connected and disconnected from each other); 3) atresia of the pulmonary valve, trunk and one pulmonary artery (the other pulmonary artery was preserved); 4) atresia of the pulmonary valve, trunk and both pulmonary arteries (the lungs are supplied with blood by the collateral systemic arteries).

C. Olin et al. (1976) distinguish 5 types pulmonary atresia: 1) atresia of the outflow tract of the right ventricle; 2) atresia of the pulmonary valve; 3) atresia of the proximal part of the pulmonary trunk; 4) diffuse atresia of the pulmonary trunk; 5) atresia of the proximal parts of the pulmonary arteries with the absence of their connection.

Pathological anatomy.

The anatomical criteria of the defect include the following 5 components: 1) atresia of the pulmonary trunk, leading to impaired communication of the right ventricle with the pulmonary arterial bed; 2) occluded output section of the right ventricle; 3) large VSD; 4) the presence of any source of collateral blood supply to the lungs; 5) dextroposition of the aortic root.

Atresia may be at the level of the right ventricular outlet, pulmonary valve, proximal pulmonary trunk, or the entire pulmonary trunk

(which in such cases looks like a narrow band) and the proximal sections of the right and left pulmonary arteries, while disrupting the communication between them. In some cases, hypoplasia of the pulmonary arteries or their local narrowing can be noted. A specific component of the defect, which distinguishes it from the common arterial trunk, is the blindly ending output section of the right ventricle and a single valve only for the aortic orifice.

The VSD is usually large, located below the supraventricular crest, in the subaortic region, and is similar to the defect seen in tetralogy of Fallot. More rarely, the VSD is located above the supraventricular crest, corresponding to the topography of the defect in the common truncus arteriosus.

In all cases, the dextroposition of the aorta can be noted. The aorta is always greatly dilated. The aortic valve usually contains three leaflets, rarely two or four. The coronary arteries are normally distributed in most cases. Rare observations include communication of the left coronary artery with the pulmonary trunk, which, in case of pulmonary atresia, is regarded as a variant of collateral pulmonary blood supply. In all cases of pulmonary atresia, right ventricular hypertrophy is noted, and in approximately 40% of cases, moderate left ventricular hypoplasia.

Among the sources of blood supply to the lungs in patients with pulmonary artery atresia and VSD, the following are noted: 1) large aortopulmonary collateral arteries; 2) open ductus arteriosus; 3) bronchial collateral arteries; 4) large mediastinal collateral arteries; 5) fistulas between the coronary and pulmonary arteries; 6) mixed molds.

The greatest difficulties are caused by the identification of systemic collateral arteries and the identification of patterns of their connection with the pulmonary arterial bed. M. Rabinovicht et al. (1981) in the pathoanatomical study established the three most common variants of systemic collateral arteries and three types of their connection with the pulmonary arterial system. The authors showed that bronchial collateral vessels most often form intrapulmonary anastomoses, when large collateral vessels, which often depart from the descending aorta, connect with the pulmonary arteries at the root of the lung (“straight” aortic arteries). Collateral vessels originating from any artery that is a branch of the aorta (for example, the subclavian artery) form extrapulmonary anastomoses ("indirect" aortic arteries).

The most common source of pulmonary blood flow is the large systemic collateral arteries, which originate from the thoracic aorta or aortic arch. In 68% of cases, the collateral arteries contain local narrowings, which are determined at the site of their departure from the aorta, along the vessel, or when they are connected to the pulmonary arteries.

With severe hypoplasia of the pulmonary arteries, it is often possible to find both true pulmonary arteries and large aortopulmonary collateral arteries in various pulmonary segments of one or both lungs - the so-called multifocal type of blood supply to the lungs.

Hemodynamics.

Hemodynamic disturbances are determined by the presence of a single main artery, the aorta, which receives blood from the right and left ventricles through the VSD. The conditions under which both ventricles function are approximately equal, therefore the same systolic pressure equal to the aortic pressure is recorded in them.

Since arterial and venous blood flows are mixed in the aorta, blood of the same type enters the systemic and pulmonary circulations. gas composition and in almost all patients, severe arterial hypoxemia is determined, the degree of which depends on the magnitude of pulmonary blood flow through collaterals.

Most patients have a small PDA. The blood flow in the lungs is sharply depleted. Relatively small volume arterial blood through the lungs returns to the left ventricle and again enters the aorta. With a large aortopulmonary communication, such as through the PDA or large systemic collateral arteries, blood flow through the lungs may be quite satisfactory or even increased. In such patients, the level of arterial hypoxemia may be moderate or minimal.

Rarely, patients with an associated large patent ductus arteriosus may experience pulmonary hypertension with sclerotic changes in the pulmonary vessels.

The literature describes cases with asymmetric pulmonary blood flow, when one lung has a collateral type of blood supply, and the source of blood supply to the second lung is an open ductus arteriosus. Consequently, in the second lung, the blood flow is increased [Bukharin V.I. et al., 1979].

Clinic, diagnostics.

The clinical picture of pulmonary at-resia with VSD is usually quite characteristic. Predominant signs of chronic oxygen starvation. However, there are no shortness of breath and cyanotic attacks, which distinguishes this defect from most forms of Fallot's tetralogy. Along with the general cyanosis that has existed since the birth of the child, the symptoms of "drumsticks" and "watch glasses" are determined. To the left of the sternum, a deformity of the chest in the form of a "heart hump" can be seen. Auscultation determines the accent of the II tone above the base of the heart and, with satisfactorily developed collaterals, a systolic-diastolic murmur in the second or third intercostal space to the right or left of the sternum. Noise is well conducted to the back.

Changes to ECG uncharacteristic. Electric axis heart is deviated to the right, there are signs of hypertrophy of the right ventricle and right atrium.

At X-ray the study shows the depletion of the lung pattern, the roots of the lungs are poorly outlined. In the presence of developed branches of the pulmonary artery, an experienced researcher sees them on a survey radiograph.

Strengthening of the pulmonary pattern is usually associated with the presence of atypical shadows of collateral vessels. In some patients, asymmetry of the pulmonary pattern (Janus symptom) may be observed, when it is strengthened on the one hand, and depleted on the other. The shadow of the heart is moderately enlarged in diameter, often of normal size. Due to the fact that the arch of the pulmonary artery sinks, and the apex of the heart is raised by an enlarged right ventricle, the waist of the heart is emphasized and the shape of the heart is similar to that found in Fallot's tetrad, i.e., in the form of a wooden shoe. In oblique projections, an increase in the right sections of the heart and a decrease in the size of the left ventricle are determined. The shadow of the ascending aorta is enlarged, the amplitude of its pulsation is increased. Thus, already on the basis of non-invasive methods of examining a patient, it is possible to make a diagnosis of pulmonary artery atresia with VSD with great accuracy.

On the ECHOCG a dilated ascending aorta and a large VSD are visible. With type I defect, a sharply hypoplastic pulmonary trunk can be seen.

Cardiac catheterization performed according to the same program as in patients with Fallot's tetrad. It is usually possible to pass a catheter from the right ventricle through the VSD into the aorta. Systolic pressure in both ventricles and aorta is the same. Arterial oxygen saturation is usually reduced. It is possible to pass a catheter into the pulmonary trunk only if a PDA is present. With this heart disease, as a rule, there is a need for catheterization (from the lumen of the aorta) of collateral vessels supplying blood to the lungs, to perform selective arteriography. To do this, the catheter is passed into the aorta antegrade from the right ventricle or retrograde through the femoral artery.

Angiocardiographic the study should begin with the introduction of a contrast agent into the right ventricle. At the same time, the occluded outlet section of this ventricle is contrasted, which confirms the absence of a direct communication between the right ventricle and the pulmonary trunk, and the contrast agent enters the ascending aorta through the VSD.

Thus, with the help of right ventriculography, the diagnosis of pulmonary artery atresia with VSD is established and the type of ventricular-arterial junction is determined.

An angiocardiographic study is the only way, which allows you to establish the sources of blood supply to the lungs. For these purposes, aortography is performed with the introduction of a contrast agent into the ascending aorta, which allows not only to differentiate this defect from OSA, but also to establish or exclude: a) large collateral arteries extending from the brachiocephalic arteries, and b) an open arterial duct. When large collateral arteries depart from the descending aorta, a contrast agent is injected through a catheter, the tip of which is placed at the border of the arch and the descending part of the aorta. At this stage of the study, the location of the origin of the large collateral artery is determined in order to perform selective arteriography at the next stage. This study is of great importance, since it allows us to more accurately judge the ways of collateral circulation in the left and right lung, as well as to resolve the issue of the existence of true pulmonary arteries and, therefore, indications for surgery [Ivanitsky AV, 1977; Podzolkov V.P. et al., 1981].

Contrasted large collateral arteries arising from the brachiocephalic arteries or the descending aorta may be of various diameters and lengths. According to M. de Leval (1983), in 50% of cases they have local narrowings, which are especially often observed at their junction with the lobar or segmental pulmonary artery. This causes a fairly frequent hypoplasia of the pulmonary arteries.

In the presence of an open arterial duct, the size of the pulmonary arteries is directly dependent on the diameter of the duct.

In those cases when using the above research methods it is not possible to obtain contrasting of the true pulmonary arteries, it is possible to introduce a contrast agent against blood flow into the pulmonary vein in order to obtain retrograde contrasting of the pulmonary arteries and their branches [Ivanitsky A. V., 1977; Nihill M. et al., 1978].

Natural course and forecast.

In the first days and weeks of life in patients with pulmonary atresia and VSD, mortality is associated with the closure of the PDA or progressive narrowing of the "large" aortopulmonary collateral arteries. Death usually occurs from increasing hypoxemia due to a decrease or almost complete cessation of pulmonary circulation. Deterioration in childhood is often associated with the fact that there is no increase in the size of the collateral arteries, according to the growth of the patient.

However, patients with a large patent ductus arteriosus and "large" aortopulmonary collateral arteries may be in a state of compensation for a long time.

indications for surgery.

Treatment is surgical only. With this type of defect, 2 types of operations are performed: palliative and radical. The need for palliative surgery in early childhood is due to progressive cyanosis due to the closing of the open ductus arteriosus and the small size of the pulmonary arteries. Therefore, the main goal of palliative surgery is to increase blood flow by performing an aortopulmonary anastomosis, which creates the prerequisites for the growth of true pulmonary arteries, and, if possible, to ligate the aortopulmonary collateral vessels. Among various types for aortopulmonary anastomoses, preference is given to the Blalock-Taussig subclavian-pulmonary anastomosis or the connection of these vessels using a Gore-Tex prosthesis.

Aortopulmonary anastomoses often create a preferential flow on the side of the connection with the pulmonary artery, and also lead to deformation, narrowing or kinking of the latter. Therefore, at present, two types of palliative operations are used to create a uniform blood flow in both pulmonary arteries in patients with type I defect (according to the classification developed by J. Somerville, 1970). The first type is the central anastomosis, which is created by connecting the hypoplastic pulmonary trunk to the left side wall of the ascending aorta. The second type of operation performed under EC conditions is the reconstruction of the outflow tract from the right ventricle by suturing a transanular patch without closing the defect. interventricular septum[Podzolkov V.P. et al., 1987]. Since hypoplasia of the pulmonary arteries is quite often observed in early childhood, such patients are shown to perform palliative operations even with moderate cyanosis.

Radical surgery is possible only with normal sizes of the pulmonary arteries. If with type I defect during correction it is possible to use a transanular patch (preferably with a single leaflet) to expand the narrowed sections, then with types II and III of defect, a radical operation can only be performed using an artificial trunk and valves of the pulmonary artery.

Surgery.

Due to the frequent detection of large aortopulmonary collateral arteries, surgical tactics for pulmonary atresia with VSD has its own characteristics. On the one hand, if the collaterals are not ligated, then the pulmonary blood flow increases. On the other hand, ligation of a collateral artery connected to a lobar pulmonary artery whose interlobar arteries have no connection with the central pulmonary arteries can lead to lung infarction. Rational tactics of surgical treatment of patients with this defect was developed by J. Kirklin et al. (1981).

Before the operation, a complete angiocardiographic examination is mandatory at the first admission of the patient to the clinic. Since hypoplasia of the pulmonary arteries is usually observed in early childhood, these patients, even with moderate cyanosis, are shown to perform the Blalock-Taussig anastomosis and ligate, if necessary, large aortopulmonary collaterals, except for those that go to the bronchopulmonary segments. favorable conditions for the operation are created when the anastomosis is performed on the side of the location of the descending part of the aorta.

Immediately after the operation, the patient is transferred to the angiocardiography room, where subclavian artery a contrast agent is injected to make sure that the blood enters all parts of the lung. If this does not happen, the patient is returned to the operating room and the ligature is removed from the collateral artery.

In the long term after the operation (at the age of 5-10 years), a repeated full angiocardiographic examination is performed. If, after anastomosis, the pulmonary arteries develop normally, then a radical operation is performed. Moreover, the expected ratio of pressure values ​​in the right and left ventricles, calculated before correction, should not exceed 0.7. If after the anastomosis there was no sufficient development of the pulmonary arteries and the expected value after correction will be more than 0.7, then one more palliative operation should be performed already under the conditions of IR creation between the right ventricle and the pulmonary arteries of an artificial trunk using a valveless or valve-containing prosthesis without closure VSD. If the repeated palliative operation contributes to the development and expansion of the pulmonary arteries, then another operation follows - the closure of the VSD.

In patients with well-developed pulmonary arteries, primary radical surgery is possible. Before performing a radical operation, it is necessary to have a complete understanding of the size of the pulmonary arteries, the left ventricle, and the nature of the collateral blood supply to the lungs. It is necessary to accurately imagine to what extent and in what areas of the lung the blood supply is carried out by true pulmonary vessels and what role belongs to the aortopulmonary collateral arteries. This is due to the fact that ligation of the collateral arteries is possible only when the pulmonary arteries have a dual blood supply: through the aortopulmonary collateral arteries and through the true pulmonary arteries. Therefore, after ligation of the collateral artery, an adequate natural route for the blood supply to the pulmonary arteries must remain.

The most difficult group for surgical treatment is represented by patients with hypoplastic pulmonary arteries. The complexity of the pathology determines the need for a multi-stage surgical approach, which most often consists of at least 3 stages. During the first stage, an operation is performed aimed at increasing pulmonary blood flow and, consequently, dilating the hypoplastic pulmonary arteries. The second stage consists in ligation of the large aortopulmonary collateral arteries or their connections with the true pulmonary arteries, which is called "unifocalization". The third stage is a radical correction: closure of the ventricular septal defect and sometimes implantation of an artificial pulmonary artery trunk. So, in one of the patients we observed with type I pulmonary atresia, multi-stage treatment consisted of 5 operations.

radical operation. The operation is performed through a longitudinal sternotomy under conditions of hypothermic IR and cardioplegia. The presence of multiple aortopulmonary collateral arteries forces a reduction in perfusion volume rates and even resort to circulatory arrest in some patients.

One of the technically difficult stages of the operation is the isolation of large aortopulmonary collaterals and bronchial arteries. This stage can be performed from the median approach by opening the anterior mediastinal pleura or the posterior pericardium between the superior vena cava and the ascending aorta. With the left-sided location of the descending part of the aorta, additional lateral thoracotomy in the fourth intercostal space is often required to isolate and bring ligatures under the collateral vessels and bronchial arteries. Median sternotomy is performed only after suturing this wound and leaving drainage. The anterior leaf of the mediastinal pleura is opened and ligatures are found under the collateral arteries.

At the beginning of EC, a decompression cannula is inserted into the left ventricle, and if necessary, the aortopulmonary collateral arteries are ligated. If there are previously imposed anastomoses of Blalock-Taussig, Waterstone-Couley and Potts, then they are eliminated according to the usual technique during CPB. In cases where there is a large return of blood through the pulmonary arteries, it is possible to isolate and clamp their distal sections during the operation, or, after opening them, insert a Fogarty catheter and obturate the lumen of the arteries.

At the next stage, the right ventricle is opened with a longitudinal incision and the VSD is closed with a patch. Further, with type I defect, the incision of the right ventricle is continued through the valve ring to the pulmonary trunk and the left pulmonary artery. As with the tetralogy of Fallot, patching expands the narrowed sections and creates a message between the right ventricle and the pulmonary arteries. However, in 50–60% of cases of pulmonary atresia (especially with type II and in some cases type 1 defects), a radical operation can be done only by creating an artificial pulmonary artery trunk using a valveless or valve-containing prosthesis. For this purpose, a transverse incision is made to open the junction of the right and left pulmonary arteries and perform a distal anastomosis, and then a proximal one with an opening on the right ventricle.

Palliative surgery-reconstruction of the outflow tract from the right ventricle without closure of the VSD is performed in patients with hypoplasia of the pulmonary arteries. The difference from the radical operation described above is that the VSD is not closed, and in young children, an autopericardial tube created during the operation is used to connect the pulmonary arteries to the right ventricle, F. Alvarez-Diaz et al., F. Puga, G. Uretzky (1982) developed a method for connecting the right ventricle to the pulmonary trunk without the use of EC. The operation consists in suturing to outer surface right ventricle and pulmonary artery patch, under which they are opened.

Postoperative complications.

Most frequent complication after radical surgery is acute heart failure, which is most often caused by high pressure in the right ventricle due to hypoplasia of the pulmonary arteries. J. Kirklin et al. (1981), after analyzing the results of surgical treatment of patients with this defect, came to the conclusion that even with a successful corrective operation, the ratio of pressure values ​​between the right and left ventricles in patients without large collateral arteries was 0.58, and in their presence, 0, 87. The authors explain this difference by anomalies of the pulmonary arteries and hypoplasia of the terminal interlobar branches in patients of the last group.

Another complication is associated with errors in assessing the blood supply to the lungs during ligation of the large aortopulmonary collateral artery leading to the lobar or segmental artery, which do not have communication with the central pulmonary arteries. This leads to a heart attack of the corresponding section of the lung with the development of respiratory failure.

immediate and long-term results.

S. Olin et al. seem to have the greatest experience in surgical treatment. (1976), who presented the results of a radical operation performed in 103 patients; postoperative mortality was 9.7%. O. Alfiery et al. (1978) noted 16% of adverse outcomes after 80 radical operations, and among 48 patients who required suturing a valve-containing prosthesis, postoperative mortality was 23%, while among 32 operated patients without suturing the prosthesis, only 6.2%.

Patients who have undergone surgery, as a rule, feel well and belong to the I or II functional class, according to the classification of the New York Heart Association. AT remote period most common causes deaths were chronic heart failure due to the remaining high pressure in the right ventricle, or a second operation, which was required due to stenosis of a valve-containing prosthesis.

This defect accounts for 1-1.5% of all CHD and is present in almost 3% of patients in critical condition. In its simplest definition, the anomaly is characterized by membranous or muscular right ventricular exit atresia with an intact interventricular septum, but it is an extremely severe defect with marked morphological heterogeneity.

In 80% of patients, atresia at the level of the valve looks like a diaphragm, in 20% of patients the infundibular part of the ventricle is atrezed. The valve annulus and pulmonary trunk are usually normal in size. The right ventricle is hypoplastic varying degrees and sharply hypertrophied. Bull et al. in 1982 classified the degree of right ventricular hypoplasia depending on the presence or absence of its three divisions - inlet, trabecular and infundibular:

in the presence of all departments, hypoplasia is regarded as moderate;

with obliteration of the trabecular part - as pronounced;

in the absence of trabecular and infundibular parts - as sharp.

High pressure is created in the right ventricle, which causes tricuspid valve regurgitation. The ventricle also unloads through the coronary sinusoids into the left or right coronary arteries. They are found in ventriculography in 30-50% of patients. Often the proximal part of the coronary arteries is obliterated. The coronary arteries are perfused with desaturated blood from the right ventricle.

A prerequisite for the survival of patients is the presence of interatrial communication and PDA.

Pulmonary atresia with a VSD occurs earlier than pulmonary atresia with an intact septum. This conclusion was made based on the analysis of a number of morphological factors - the diameter of the pulmonary trunk, the anatomy of the valve and the arterial duct. Pulmonary artery atresia with VSD is formed on early stages morphogenesis of the heart, during and immediately after the separation of the ventricles. Pulmonary atresia with an intact ventricular septum forms after this, so it is likely that it is acquired due to prenatal inflammatory process, not a bookmark defect. Perhaps this applies to those forms of defect in which the size of the right ventricle is almost normal and the obliterated pulmonary valve has well-formed three commissures. The inflammatory hypothesis is not supported by the absence of obvious histological signs of acute or subacute inflammation in fetuses and newborns. There is no explanation why in cases of a very small right ventricle with ventricular-coronary connections, delayed maturation occurs earlier than in fetuses with a well-formed right ventricle and a pulmonic valve that is not perforated. The right-sided aortic arch observed in some cases also does not fit into the hypothesis of the inflammatory origin of the defect.

Changes in the main components of the system in pulmonary artery atresia with an intact interventricular septum

Pulmonary arteries

Pulmonary circulation in the vast majority of cases is carried out through the left ductus arteriosus, although very rarely through large aortopulmonary collaterals. Usually there is a pulmonary trunk with an atrezirovanny valve. In patients with a well-formed infundibular section of the right ventricle, the atretic pulmonary valve consists of three semilunar cusps fused along the commissures.

In patients with a tiny right ventricle and a sharply narrowed or atrezed infundibular region, the pulmonary valve is primitive.

The branches of the pulmonary artery are usually confluent. They are developed normally or somewhat narrowed. The expressed underdevelopment of branches of a pulmonary artery meets seldom. The left branch may be narrowed at the confluence of the arterial duct, so the duct closes earlier with this defect than with pulmonary atresia with VSD. Occasionally, the pulmonary arteries do not merge and each is supplied by its own ductus arteriosus.

In patients with extremely severe tricuspid valve insufficiency, the lungs are compressed by a sharply dilated heart, but are not underdeveloped, as in diaphragmatic hernia.

Right atrium

The coronary sinus usually opens in the right atrium. Sometimes it is narrowed or atrezirovan. In these cases, the coronary system is unloaded into the left atrium through the uncovered coronary sinus.

The absence of a natural exit of blood from the right ventricle predetermines the presence of a right-left shunt at the atrial level through oval window or secondary ASD. Cases of prenatal closure of the foramen ovale lead to inevitable fetal death. Rarely with intact interatrial septum or with a restrictive foramen ovale, there is an alternative systemic venous return route via the coronary sinus fenestration to the left atrium. In conditions of right atrial hypertension, the primary septum may protrude to the left in the form of a hernial sac prolapsing into the mitral valve.

Tricuspid valve and right ventricle

The tricuspid valve is rarely normal in pulmonary atresia with an intact ventricular septum. Its features range from severe stenosis to severe regurgitation. With a stenotic valve, the ring is narrowed and muscular. All components of the valvular apparatus are abnormal:

free edges of valves are thickened;

chords are shortened and thickened;

papillary muscles are parachute-shaped.

The most pronounced narrowing and even obstruction of the valve is observed in patients with ventricular underdevelopment, and, conversely, in patients with a sharp dilatation of the ventricle, the tricuspid valve is enlarged and incompetent. With severe regurgitation, the tricuspid valve has signs of displacement and dysplasia. Ebstein's anomaly is found in 10% of patients at autopsy. In some cases, an obstructive form of the Ebstein valve is found.

Throughout the surgical era, researchers have attempted to quantify the size of the right ventricle, as this parameter is key to tactical decision making. Descriptive criteria "small" or "large" and quantitative angiocardiographic measures of inflow and outflow axis length using the Simpson rule are currently unpopular. Wide application obtained a calculation of the diameter of the tricuspid valve Z, referred to the surface of the body and compared with the norm, published by Rowlatt et al. in 1963:

"Measured Diameter - Average Normal Diameter",

Where 2-score = standard deviation from mean normal diameter.

The more negative meaning indicator 2, the smaller the size of the tricuspid valve. The higher the value of indicator 2, the more valve and the more pronounced regurgitation. Data from multicenter studies have shown that there is a close correlation between tricuspid valve 2-score and right ventricular cavity size. This correlation also exists in the presence of ventriculocoronary connections. To estimate the size of the tricuspid valve, it was also proposed to calculate the ratio of the diameters of the tricuspid and mitral valves.

Another group of surgeons adheres to the morphological approach in assessing the functional viability of the right ventricle. Although there is no agreement on whether the right ventricle is embryologically established as two or three parts, there are examples of congenital heart pathology that suggest that a normally formed right ventricle has three fused components: inflow, apical trabecular and outflow. Based on this, a classification of pulmonary atresia with an intact interventricular septum was constructed. Favorable cases of this defect are represented by all three parts of the ventricle, while with an extreme degree of hypoplasia there is only an inflow part. The intermediate form is characterized by the presence of supply and output parts. FROM clinical point From the point of view, this division is quite correct; however, it should be taken into account that embryologically the ventricle was probably formed as a three-component one, and the subsequent muscular hypertrophy and growth practically obliterated the apical and excretory zones.

left ventricle

The left ventricle may be more or less hypertrophied and inflexible, especially in patients past infancy. In half of the patients, chordae mitral valve shortened and dysplastic. In patients with hypersystemic pressure in the small right ventricle, the outlet portion of the interventricular septum sometimes bulges into the cavity of the left ventricle, causing subaortic narrowing. Under these conditions, the Fontan operation becomes dangerous due to the unfavorable ratio between the mass of the left ventricle and the end-diastolic volume. Cases of aortic valve stenosis have been described in newborns and in older children. Histopathological changes in the left ventricle may affect the long-term results of treatment.

Surgical tactics and treatment outcomes are determined by the presence of anatomical risk factors. Among them, in addition to the size of the tricuspid valve and the right ventricle, ventriculocoronary connections and dependent on the right ventricle are of fundamental importance. coronary circulation.

coronary circulation

For atresia of the pulmonary artery with an intact interventricular septum, a deep disorganization of the coronary circulation is characteristic. It is based on the presence of ventriculocoronary connections and myocardial sinusoids.

These specific connections between the cavity of the right ventricle and the coronary arteries were found at autopsy more than 75 years ago. Freedom and Harrington were the first to suggest that they may be the cause of myocardial ischemia. Gittenberger-de Groot and colleagues recently published a detailed study of the histopathology of the ventriculocoronary arterial connections. According to the pooled data from several centers, among 140 patients, normal coronary arteries occurred in 58%, small and large fistulas were identified in 15% and 17%, respectively. In 10 patients, stenoses of the coronary arteries were found. The mean Z-score for this patient cohort was minus 1.6.

Histopathological changes in the coronary arteries are manifested by myointimal hyperplasia with a high content of mucopolysaccharides. They are observed in both intramural and extramural coronary arteries. Violations of the microstructure are expressed in varying degrees - from a slight thickening of the intima and media, in which the integrity of the elastic plate and the normal lumen of the vessel are preserved, to the complete degeneration of the morphology of the vascular wall, manifested by the replacement of the normal structure with fibrous cell tissue containing disordered elastin bundles, and severe stenosis or obliteration of the lumen . Some morphologists have defined these changes as fibroelastosis of the coronary arteries. Hyperplasia of the intima and smooth muscle layer of vessels, which does not fit into the concept of "fibroelastosis", is observed only in patients with high pressure in the right ventricle and ventricular-coronary connections. This suggests that in the pathogenesis vascular changes the leading role is played by damage to the intima by turbulent blood flow coming under high pressure from the right ventricle through the ventriculocoronary canals. In intra- and extramural coronary arteries, remote from the ventricular-coronary fistulas, vascular damage is less pronounced.

Right ventricular dependent coronary circulation

Another pathology of large coronary arteries is also specific for this defect: lack of connection between the aorta and the proximal part of one or two coronary arteries, narrowing or interruption of the coronary arteries along their length, and the presence of large fistulas between the right or left coronary arteries and the cavity of the right ventricle. This feature defines the surgical algorithm.

AT normal heart coronary blood flow is carried out in the diastolic phase. The blood supply to the heart deteriorates with a decrease in diastolic pressure in the aorta, shortening of the diastole, a decrease in aortic distensibility and with anatomical factors, such as narrowing of the coronary arteries, in particular, occurring in pulmonary atresia with an intact interventricular septum. With this defect, the coronary circulation is fully or partially dependent on the right ventricle, venous blood enters the coronary artery system retrogradely in the systole phase under suprasystemic pressure. According to the multicenter studies of the Congenital Heart Surgeon Study, in 9% of 145 patients, coronary blood flow was entirely provided by the right ventricle. This percentage roughly corresponds to that in other publications. Surgical decompression of the right ventricle can lead to a decrease in perfusion pressure and leakage of blood from the coronary arteries into the ventricle, myocardial ischemia, infarction and death. A unique case of the absence of a proximal aortocoronary connection with the blood supply to the left coronary artery through the direct systemic artery, which originates from the descending thoracic aorta, is described.

All parents want their children to be healthy. And most adequate mothers and fathers begin to take care of this even before the active planning of the child. They visit the right doctors undergo many studies, accept vitamin preparations eat a balanced diet and lead a completely healthy lifestyle. But sometimes all these measures are not enough. Even during the most prosperous pregnancy, something can go wrong, and the fetus can develop various disorders. Pulmonary atresia is one of these, we will consider the types of this condition, discuss its features in newborns and clarify what kind of prognosis doctors give to infants with this diagnosis.

Pulmonary atresia is a congenital malformation of the heart. In this condition, the child does not have a normal communication between the right ventricle and the pulmonary artery that exits it. Such a violation can develop if there is a complete fusion of the cusps of the pulmonary valve or fusion of the pulmonary trunk. As a result of pulmonary artery atresia, blood from the right ventricle is not able to enter the pulmonary circulation, which in turn significantly disrupts hemodynamics, makes normal gas exchange and the activity of the body as a whole impossible.

In some cases, pulmonary atresia is accompanied by other disorders. At little patient not only the complete absence of an opening in the pulmonary trunk can be observed, but also a significant decrease in the volume of the right ventricle, and a significant underdevelopment of the tricuspid valve. In some cases, the pulmonary trunk is completely absent.

At the same time, the child often retains such embryonic structural features, as an open ductus arteriosus, as well as an oval window. They support respiratory function, since blood through them can penetrate into the pulmonary artery.
Types of pulmonary atresia

There are four main varieties of this defect:

Atresia of the pulmonary valve - the patient has both the pulmonary trunk and both arteries;
- atresia of the valve of the pulmonary artery, as well as its trunk - the patient has only arteries;
- atresia of the pulmonary valve, trunk, as well as one pulmonary artery - only one pulmonary artery remains intact;
- atresia of the pulmonary valve, trunk and both arteries - blood circulation in the lungs can be carried out only thanks to the collateral systemic arteries.

Danger of pulmonary atresia

Pulmonary atresia is a rather rare and dangerous pathology. With such a defect, blood with a low oxygen content circulates through the body of the newborn. And oxygen deficiency eventually causes the death of brain cells.
Pulmonary atresia poses a threat to the life of the child in the first weeks and days of his life.

Symptoms of pulmonary atresia

The disease is diagnosed already in the first hours of a newborn's life. But sometimes its symptoms appear only a few days after birth. Pulmonary atresia results in a bluish discoloration of the skin. Doctors classify this condition as cyanosis; oxygen starvation of the brain leads to it. In addition, the child often and difficult to breathe, he has shortness of breath. When feeding, a newborn gets tired very quickly.

Can children with pulmonary atresia be helped?

Today, doctors with such a diagnosis can offer surgical intervention: radical or palliative.

A radical operation allows you to eliminate the causes of the disease, it is carried out with the first type of disease - when both pulmonary arteries are present in a small patient.
In the second and third types, radical surgery is also possible, but doctors have to use an artificial trunk and pulmonary valves.

Palliative surgery is not aimed at eliminating the cause of the defect, but at increasing the blood supply to the lungs. It is performed with progressive cyanosis. Palliative surgery involves the imposition of an aortopulmonary anastomosis, which creates the prerequisites for the active growth of the pulmonary arteries. Immediately after the connection is formed, doctors perform a secondary angiocardiographic examination, which should show that all parts of the lung are bathed in blood. If this does not happen, the patient is operated on again.

Five to ten years after the palliative surgery, doctors perform another angiographic examination. In the event that during this time the pulmonary arteries have developed normally, radical surgery is performed.

Pulmonary artery atresia in newborns - what is the prognosis?

With timely therapy, the prognosis of pulmonary atresia in newborns is quite favorable. With the first type of this defect, postoperative mortality is 6.2%, however, with the second and third types of the disease, it increases to 23% (if it is necessary to sew in a prosthesis of the arterial trunk and valve).

In most cases, patients feel well after surgery, and mortality occurs due to heart failure due to high blood pressure blood in the right ventricle.

Lack of therapy is fraught with the death of the patient from oxygen starvation in the first weeks after birth.

At an older age, children with operated pulmonary atresia should be constantly monitored by a cardiologist. They are more likely to develop endocarditis.

Additional Information

Many children who have undergone major surgery in childhood face frequent colds over time. They need to strengthen their immunity, and traditional medicine will come to the rescue in this matter.

So pine needles give an excellent effect, beneficial features which strengthens the immune system. Rinse a couple of tablespoons of pine needles and brew with a glass of boiling water. Heat the medicine to a boil and boil over low heat for twenty minutes. After that, cool the broth for half an hour and strain it. Sweeten the drink with juice and give it to your child a couple of tablespoons at a time, three times a day.

Pulmonary atresia is a severe and rare congenital heart disease, which is formed due to the fact that the artery does not depart from the right ventricle. For this reason, it does not fulfill its function, the blood is not saturated with oxygen and gas exchange in the body is difficult.

This defect is life-threatening, since the first days after birth, the blood flow is maintained by the PDA and aortopulmonary collateral arteries. When this blood pathway closes, the child dies from lack of oxygen. Sometimes blood flow continues with an ASD or VSD when there is communication between the right and left sides of the heart.

Fortunately, atresia in newborns is not so common. Less than 3% of children with congenital heart disease are susceptible to this pathology. At the same time, the birth rate of children with heart disease is also not high - less than 10 children per 1000 newborns.

Artery

In medicine, there are four types of atresia of this type.

1. Malformation of the valve of the artery, but at the same time the artery and all its branches are developed, which allows for normal blood exchange.
2. Underdevelopment of the artery trunk, however, all branches are developed to the end.
3. Underdevelopment of the valve, trunk and right or left branch of the artery.
4. Malformation of the trunk, valve and all branches of the artery. In the body, only collateral circulation occurs, since the artery is not developed.

Causes of the disease

Until now, scientists have not figured out why children are born with congenital heart defects, in particular, such as arterial atresia.

It is only known that a mutation becomes a stimulus for the development of pathology, that is, a gene change that appears spontaneously or under the influence of external factors.

Researchers identify two theories of the causes of the disease. Both were developed in past centuries.

1. Back in 1875, K. Rokitansky came to the conclusion that the disease occurs due to the fact that at a certain stage in the development of a new organism in the womb, his heart stops developing.
2. In 1923, S. Spitzer stated that a defect is formed due to a return to a certain stage in the evolutionary development of organisms.

External factors include mutagens. They are of the following types:

• chemical (for example, taking antibiotics by a pregnant woman);
• physical (ionizing, and in particular ultraviolet radiation);
• biological (alcohol intake or smoking by the mother, diabetes mellitus or rubella, which adversely affect the proper development of the heart).

In addition to LA atresia, there is atresia of the aorta and the mouth of the coronary artery. Wherein coronary vessel is filled through extended sinusoids, which in medicine is called the coronary way of blood circulation. Such a coronary way of blood circulation worsens the dangerous pathology many times, as there is a large load on the aorta.

Symptoms

The deviation may appear immediately after birth or after a few days. Main symptoms:

• the skin becomes bluish in color due to a lack of oxygen in the blood and oxygen starvation of the brain, in medical circles this process is called cyanosis;
• when screaming, sucking, or any other form of physical activity the skin turns blue even more;
• the baby quickly gets tired when feeding;
• the child breathes with difficulty and too often, he has shortness of breath;
• there is a change in the shape of the chest;
• fingers thicken and resemble drumsticks, nails change color.

The severity of certain symptoms depends on the severity of the disease and the degree of defect.

Diagnostics

Babies are diagnosed with LA atresia immediately at the hospital. But it happens that the pathology manifests itself even after a few days, when the mother and child have already left the medical facility.

Measures primary diagnosis include 6 methods.

1. Chest x-ray. The picture shows an increase in the right ventricle, the shadow of the ascending aorta is expanded, the contour of the lungs is fuzzy.
2. Electrocardiography, which reveals the dominance of the right ventricle, which is not typical for newborns. Even with the help of this method, stenosis can be detected.
3. Echocardiography, which determines the structure of the valves and the degree of development of the defect.
4. Phonocardiography, which detects extraneous and pathological heart murmurs. Auscultated and blood flow in the aorta.
5. Doppler echocardiography to detect the impossibility of blood flow in the body through the LA valve.
6. Angiocardiography, which is considered a mandatory measure. It reveals anomalies in the structure of blood vessels.

Treatment

In today's world, atresia or artery fusion is treated only with the help of surgery. To prepare for the operation, the doctor may prescribe medications, but not in the role of self-treatment.

The operation is carried out in two types.

1. Radical surgery. Most often, it is carried out with type 1 disease, when the newborn has fully developed LA. However, such an operation is also performed with types 2 and 3, then surgeons install artificial valves and trunk of arteries.
2. Palliative surgery. Carry out with cyanosis, especially progressive. In this case, with the help of an aortopulmonary anastomosis, the prerequisites for the development of LA are created.

After the operation, a second examination is carried out, and if the blood flow is not restored, then a secondary operation is performed.

Type 4 atresia is practically not subject to surgical intervention.

When treated on time, the chance of recovery reaches 80% after a year, and 60% after 4 years.

Complications

Unfortunately, even the timely establishment of the defect and its treatment does not prevent the development of complications. The most frequent of them:

• developmental delay;
• growth retardation;
• heart failure due to increased blood pressure in the pancreas;
• breathing problems;
• damage to the heart by a secondary bacterial infection.

Tetrad

- a kind of heart disease, which is accompanied by stenosis or atresia of the LA. Plus, there is VSD, enlargement of the pancreas, dextrapposition of the aorta. Symptoms of the pathology are similar to LA atresia:

• breathing problems;
• developmental delay;
• frequent dizziness.

Tetralogy of Fallot is found in 1 out of 4 thousand infants, which is 5% of all children with congenital heart defects.

With tetralogy of Fallot with atresia, the patient needs urgent surgery. Newborns with a severe form are first assigned a palliative operation (anastomoses), and after reducing the risk of complications, a radical surgical intervention is performed.

Stenosis

Stenosis is a pathology that manifests itself in Fallot's tetrad or separately. At the same time, the lumen of the aircraft is narrowed. blood passes partially. At the same time, a characteristic noise is heard over the artery.

It can be detected using a Doppler study. Echocardiography shows an increase in the size of the right ventricle.

The narrowing is eliminated by balloon expansion or implantation of a special medical stent. Valvular stenosis is corrected by balloon valvuloplasty or commissurotomy. Moderate narrowing does without surgical intervention.

Forecast and prevention

Atresia is a very dangerous pathology. If the operation was carried out in a timely manner and correctly, the baby will grow up completely healthy. When predicting the manifestation of the disease in the future, the doctor must take into account the severity of atresia and the quality of the operation performed.

Important! A baby with atresia needs constant medical supervision.

To minimize the occurrence of illness, future mommy is obliged:

• do not come into contact with physical and chemical mutagenic substances;
• avoid contact with people suffering from measles, rubella, influenza and similar infections;
• completely exclude alcohol-containing drinks, nicotine, medicines (antibiotics) and narcotic substances from your diet;
• undergo a genetic examination if there were people with heart defects in the family.

These preventive measures will significantly reduce the likelihood of a future child developing serious disorders in the structure of the cardiovascular system.