Pulmonary artery atresia with intact interventricular septum in children. Pulmonary artery atresia with ventricular septal defect

Atresia pulmonary artery- this is a congenital pathology of the heart, in which the mouth and valve of the pulmonary artery are changed, as a result, blood from the right ventricle does not enter the pulmonary artery. It occurs in 1-3% of cases among congenital heart defects. The severity of this disease is due to the lack of effect of conservative therapy and poor prognosis in the absence of timely surgical treatment. Most newborns with pulmonary atresia die within 2 weeks after birth, the rest - during the first year of life.

Causes and classification of pathology

Pulmonary atresia is formed antenatally, semilunar valves (endocardial ridges) fuse in the fetal heart. This causes fusion of the vessel, that is, atresia of the pulmonary valve occurs. The immediate causes of the disease are not yet fully understood. Probably, the formation of the defect is associated with the influence of various adverse factors on the body of a pregnant woman. In particular, taking antibiotics, maternal rubella, diabetes, smoking, which leads to disruption of embryogenesis.

The malformation may involve an artery on different levels. Depending on this, the types of pulmonary atresia are distinguished:

1. Changes affect only the pulmonary valve. going on normal development branches and trunk of the artery, and blood enters the lungs with the help of ductus arteriosus.
2. Hypoplasia captures not only the valve, but also, the branches remain intact.
3. Damage to the valve, trunk and one of the branches of the pulmonary artery. Only the second branch is saved.
4. Atresia of the valve, trunk and two pulmonary arteries. In the lungs, blood flow is carried out only through additional collateral arteries.

In most cases, normal blood flow in the lungs is achieved through the formation of collaterals - additional arteries that extend from the aorta above the site of the lesion. At the same time, many patients have, with the help of which blood can also enter the lungs. In the presence of large collaterals or a sufficiently wide arterial duct, blood circulation in the lungs can reach almost the proper volume. In such cases, the degree of arterial hypoxemia may be insignificant and almost not manifest clinically.

Clinical symptoms

Pulmonary atresia in newborns is clinically manifested immediately after birth. Symptoms appear in the first hours or days. All manifestations are due to "oxygen starvation" -. This means not enough oxygen enters the arterial blood.

The main symptoms include:

• (bluish tinge of the skin), aggravated by any physical activity(sucking, screaming);
• shortness of breath - frequent, shallow breathing;
• the child quickly gets tired during feeding;
• the phalanges of the fingers thicken and acquire the characteristic appearance and shape of "drumsticks", and the nails become similar to "watch glasses";
• shape changes chest.

These symptoms are associated with the development of heart failure against the background of serious hemodynamic disorders caused by the discharge of venous blood from the right heart to the left. The severity of symptoms depends on the degree of the defect.

Diagnostic methods

Primary diagnosis is based on clinical manifestations. To the main diagnostic measures include:

1. : accent II tone and systolic-diastolic murmur at the base of the heart.
2. Electrocardiography to determine the presence of overload or hypertrophy of the right heart. Sometimes ischemic changes are possible.
3. echocardiography ( ECG of the heart) to determine the degree of defect, the structure of the valves, visualization of pathological blood flows.
4. Chest x-ray to assess lung pattern and heart size.
5. Phonocardiography to detect abnormal heart murmurs.
6. Angiocardiography - visualization of the cavities of the heart and the main vessels using the introduction contrast medium. Allows you to determine the presence of collaterals, ductus arteriosus.
7. Cardiac catheterization (probing). With the help of a Swan-Ganz catheter, the pressure in various cavities of the heart is determined. Pulmonary atresia manifests high pressure in the right side of the heart.

The course of the disease and prognosis

In patients with pulmonary atresia, there is no blood flow from the right ventricle to the lungs, instead, venous blood from the right side of the heart goes directly to the left. As a consequence, in arterial blood oxygen deficiency occurs (arterial hypoxemia), which leads to the formation of heart failure.

The survival of the child depends directly on the possibility of blood supply to the pulmonary arteries using additional blood supply pathways. With atresia of the pulmonary arteries in newborns, the prognosis is unfavorable - in the first few days fatal outcome observed in more than 50% of children, and within six months - about 85%. In the first days and weeks after birth, such high percent mortality is due to fusion of the arterial duct or severe narrowing of the aorto-pulmonary collaterals.

If the arterial duct does not overgrow and there are a sufficient number of large collaterals that provide normal blood flow in the lungs, then the disease long time may be asymptomatic. However, as the child grows, his condition may worsen. The size of the collateral vessels does not match the growing oxygen needs of the growing patient.

Therapeutic measures and complications

When a diagnosis of pulmonary atresia is established, treatment should begin immediately. Because the conservative therapy in this situation is ineffective, treatment is reduced to surgical correction vice. The sooner the operation is performed, the more likely the child will survive. Medical treatment appointed only as preparatory phase before surgery, as well as at the stage of recovery after surgery.

The volume of surgical treatment is determined individually, depending on anatomical features vice. The operation consists in performing aorto-pulmonary bypass and pulmonary valvotomy (). Aorto-pulmonary bypass needed for recovery normal blood flow in the lungs. Valvotomy (dissection of the valve leaflets) is performed with normal sizes of the valve ring and unchanged valve leaflets. If there is a stenosis (narrowing) of the valve, then transannular plasty is performed. Sometimes surgical treatment takes place in several stages.

Improving the patient's well-being usually occurs almost immediately after the operation, as the blood flow in the pulmonary artery is restored. After surgical correction, the symptoms of the disease may completely disappear. However, even after successful surgical treatment, a high percentage of mortality among newborns with this defect remains. Within a year after successful surgical treatment, on average, 70-80% survive, within 4 years - about 60%.

After the operation, mandatory medical support is required. Patients continue to be under the supervision of a cardiologist for life, drug maintenance therapy is carried out, and, if necessary, a second operation is prescribed.

In the presence of pulmonary atresia, even with surgical treatment, the following complications may develop:

• growth retardation and general development of the child;
• chronic heart failure;
• - secondary connection bacterial infection with damage to the inner lining of the heart - the endocardium;
• respiratory failure;
• due to a lack of oxygen in the arterial blood.

Pulmonary atresia is quite rare, but very serious illness, which develops rapidly and poses a significant danger in the first days of a child's life. It is very important to confirm the diagnosis as soon as possible and to short time to carry out surgical treatment, because the life and health of the baby is on the account.

Tetralogy of Fallot with atresia JIA). The combination of the absence of direct blood flow from the RV (right ventricle) to the LA (pulmonary artery) and tetrad-like VSD (ventricular septal defect).

The anatomy of the pulmonary bed is divided into three types:

– Type A: the source of blood supply is the PDA (open ductus arteriosus), the pulmonary arteries are normally developed.

– Type B: the source of blood supply is PDA and BALC (large aorto-pulmonary collaterals), native pulmonary collaterals are hypoplastic, often not connected to each other.

– Type C: the source of blood supply is BALK, there are no native pulmonary arteries.

This variant can be characterized as an extreme form of TF. In this case, the entire flow of venous blood is directed through the VSD to the aorta, and pulmonary blood flow is provided through the patent ductus arteriosus and/or through the aortopulmonary collaterals. In the presence of collaterals, often the branches of the pulmonary artery do not connect with each other, i.e. non-confluent. Despite the presence of PDA and collaterals, the blood flow in the ICC is insufficient and hypoxia is pronounced from birth.

In the case of PAL (pulmonary artery atresia) with VSD, most patients do not survive to two years, but in the presence of large and developed aortopulmonary collaterals, life expectancy can be rare cases be 15 years or more.

CLINIC

a. Clinical manifestations of the disease:

– cyanosis from birth (the degree of cyanosis depends on the functioning of the ductus arteriosus and on the development of aortopulmonary collaterals);

- shortness of breath (tachypnea).

b. Physical examination:

- a heart murmur is usually absent, but sometimes there is a murmur of a functioning PDA at the base of the heart and / or a murmur of blood flow through the aorto-pulmonary collaterals above the surface of the chest.

DIAGNOSTICS

1. Electrocardiography

- signs of hypertrophy of the right and left pancreas.

1. echocardiography

Diagnostic criteria:

– LA valve atresia;

- pronounced hypertrophy up to obstruction of the output section of the right ventricle (the pulmonary cone is not visible);

- hypoplasia of the LA trunk or its absence, depending on the type of atresia, there may be narrowing of the LA branches;

- open ductus arteriosus;

– ventricular septal defect, sometimes a defect interatrial septum.

TREATMENT AND OBSERVATION

1. Observation and treatment of patients with uncorrected ALA

a. IV infusion of prostaglandin E preparations is indicated (in order to prevent the closure of the arterial duct. The infusion can be prolonged until surgical intervention,

b. Correction of metabolic disorders.

in. Prevention of bacterial endocarditis when indicated.

1. Surgery

Indications for surgical treatment:

– the diagnosis of ALA in all variants is absolute reading to emergency surgery.

Contraindications for surgical treatment:

- Availability absolute contraindications on concomitant somatic pathology;

- high pulmonary hypertension caused by BALK (large aorto-pulmonary collaterals) (OLS> 10 U d / m 2 initially and> 7 U / m 2 after the use of vasodilators).

Surgical tactics

To determine the surgical tactics evaluate:

- total neopulmonary arterial index, which is calculated as the ratio of the sum of the cross-sectional area of ​​the right and left coronary arteries and BALC to the body surface area;

– Nakata index (the ratio of the sum of the cross-sectional area of ​​the right and left aircraft to the body surface area);

is the ratio of the number of segments of the lungs supplied by the LA to the number of segments supplied by the BALC (s LA: s BALC).

The VSD should be closed no earlier than the final unifocalization of the pulmonary blood flow. When performing one-stage unifocalization, the decision to immediately close the VSD is made during the operation. For this purpose, a test is performed with the injection of blood into the bed of the ICC (small circle of blood circulation). If during the test the average pressure in the channel is less than 30 mm Hg, it is possible to close the VSD. Simultaneous unifocalization is carried out if the patient's weight is more than 3.5 - 4 kilograms and the PNAI index (complete neopulmonary arterial index) is more than 150 mm2/m2.

Patients in whom MCC is supplied by BALK remain asymptomatic for a long time, as long as the circulation of BCC and MCC is balanced. When establishing a diagnosis in patients older than 1 year, it is necessary to individually approach the determination of indications for surgical treatment, weighing the dangers of the natural course of the defect with potential risks surgical treatment.

Surgical technique

Radical correction consists of two components: the formation of the ICC bed (unifocalization) and the connection of the ICC bed with the source of its blood supply - temporary (systemic-pulmonary shunt) or permanent (valve-containing conduit in the RV-LA position).

Unifocalization of pulmonary blood flow

To determine tactics in relation to BALK, the significance of each of them for the blood supply to the lung tissue is determined.

BALC can:

- supply blood lung segment together with native aircraft,

- fall into native LA,

– to supply blood to a segment of the lung in the absence of its blood supply from the native LA.

The first two groups of BALK can be ligated and crossed.

BALK of the third group must be included in the bed of the native pulmonary artery or combined with each other in the absence of native LA, forming the bed of the ICC.

Connection of the ICC with a source of blood supply.

The imposition of a systemic-pulmonary anastomosis is performed in accordance with the principles described above. If the pulmonary arteries are connected to each other, it is possible to perform a bilateral shunt.

Prosthetics of the LA trunk using a valve-containing conduit. If the patient has type A ALA, this operation is a method of radical correction. In type B and C, with the help of this intervention, a radical correction of the defect is completed. The conduit is connected to the right ventricle through ventriculotomy in the area of ​​the RVOT, and to the ICC bed through a wide anastomosis and plasty with the tissues of the conduit.

To determine tactics in relation to VSD during surgical treatment, it is possible to conduct a test to determine " bandwidth» LA. A cannula attached to the arterial line is installed in the LA, and blood is pumped on full EC. With an average pressure in the LA less than or equal to 30 mm Hg. VSD plastic surgery is possible.

Specific Complications surgical treatment:

– residual VSD;

– damage to the coronary arteries;

- arrhythmias (atrioventricular blockade, ventricular tachycardia);

- RV dysfunction (residual cyanosis - RV weakness in the presence of a fistula in the MPP, or low cardiac output of RV weakness without a fistula in the MPP);

- chylothorax;

- conduit stenosis.

Postoperative follow-up

1. Observation is carried out every 6-12 months for life. The state of shunts, anastomoses, valve-containing conduits, functional state ventricles and heart rate.
2. Prevention of bacterial endocarditis is carried out according to indications for life.
3. The admissibility of physical education after the correction of the defect is determined individually. Most patients after CHD correction have I-II functional class of heart failure.

This defect makes up 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 atresia of the right ventricular outlet 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 ring and pulmonary trunk are usually normal sizes. 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 in the early stages of cardiac morphogenesis, 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 region of the right ventricle, the atretic pulmonary valve consists of three semilunar cusps fused along 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 DMZHP. 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 outflow of blood from the right ventricle predetermines the presence of a right-left shunt at the atrial level through the foramen ovale or secondary ASD. Cases of prenatal closure of the foramen ovale lead to inevitable death fetus. Rarely, with an intact atrial septum or with a restrictive foramen ovale, there is an alternative systemic venous return route through 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. The calculation of the diameter of the tricuspid valve Z, referred to the surface of the body and compared with the norm, was widely used, published by Rowlatt et al. in 1963:

"Measured Diameter - Average Normal Diameter",

Where 2-exponent = standard deviation from the average normal diameter.

The more negative meaning indicator 2, the smaller size tricuspid valve. The higher the value of indicator 2, the more valve and the more pronounced regurgitation. Data multicenter studies showed that there is a close correlation of the tricuspid valve 2-score with the size of the cavity of the right ventricle. 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 congenital pathology hearts, which allow us to state 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 laid down 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, the mitral valve chords are 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 great content 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 a complete degeneration of the morphology vascular wall, manifested by the replacement normal structure 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.

Anatomy and Physiology

Blood entering the right ventricle from the right atrium leaves its cavity through the tricuspid valve back to right atrium and through the interatrial message enters the left atrium. Thus, the presence of communication between the atria is life-supporting. Therefore the character clinical course disease and the very life of the patient depend on the size of this message. The same communication that ensures the viability of the patient is an open ductus arteriosus, the only source of, carrying out pulmonary circulation, and closing one of these messages results in the immediate death of the patient.

Clinic and diagnostics

At x-ray examination the shadow of the heart does not have a characteristic outline. The pulmonary pattern is usually depleted. With echocardiography, it is possible to assess the degree of right ventricular hypoplasia, the presence and size of the patent ductus arteriosus and interatrial communication. In some cases, a high-quality echocardiographic examination can eliminate the need for X-ray surgical studies, which are undoubtedly dangerous in these patients, and, if indicated, will only allow closed atrial septostomy to adequately increase interatrial communication.

The minimum program of X-ray surgical studies for this pathology includes:
1. Catheterization of the right heart.
2. Catheterization of the left ventricle through the interatrial communication.
3. Right ventriculography in standard radiological projections.
4. Left ventriculography in standard radiological projections.

During catheterization of the heart cavities, an increase in mean pressure in the right atrium is determined and systolic pressure in the right stomach. With a small amount of interatrial communication, there is a mean pressure gradient between the right and left atria, indicating the inadequacy of this communication. Right ventriculography makes it possible to accurately establish the diagnosis and objectively assess such an important sign of a defect for subsequent surgical treatment as the degree of right ventricular hypoplasia.

Left ventriculography is performed to better visualize the size of the patent ductus arteriosus, the trunk of the pulmonary artery and its branches, which are also of fundamental importance for surgical treatment. This method of contrasting the left parts of the heart, compared with aortography, is the least traumatic, since in most cases the catheter freely, without much effort, passes through the interatrial communication into the left atrium and then into the left ventricle. In this case, there is no need for long-term manipulation of the catheter in the heart cavity to pass into the aorta or its retrograde contrast enhancement.

Right ventriculogram in anteroposterior (a) and lateral (b) projections. A contrast agent is injected into the right ventricle. Visible right ventricular hypoplasia with pronounced sinusoids and occlusion of the right ventricular outlet at the level of the pulmonary valve. With an intact interventricular septum and insufficiency of the right atrioventricular orifice, contrasted blood enters from the right ventricle into a significantly enlarged cavity of the right atrium

Based on the foregoing, the tactics of surgical treatment of newborns with severe anatomical variants of Atr.LA with STEMI, who are in critical condition, is as follows: after confirming the diagnosis and determining the indications in the least traumatic way, a closed atrial septostomy is performed to increase interatrial communication. After that, the patient is immediately transferred to the operating room for the imposition of a systemic-pulmonary anastomosis or a pulmonary valvotomy.

Atresia of the right atrioventricular opening

Anatomy and Physiology

The variety of anatomical variants of AVAVO and its accompanying anomalies determines the difference between hemodynamic disorders and clinical manifestations vice. Hemodynamics in all anatomical variants of the defect has common features. Deoxygenated blood from the right atrium, bypassing the right ventricle, enters the left atrium through the interatrial communication, where it mixes with the oxygenated blood of the latter. Then the mixed blood enters the left ventricle and through the defect of the interventricular septum into the hypoplastic right ventricle and into the main vessels.

Clinic and diagnostics

X-ray examination reveals one or another degree of enlargement of the heart due to hypertrophy of the left ventricle and right atrium. Echocardiographic examination allows to put with a high degree of certainty correct diagnosis: no echo from tricuspid valve, location small cavity right ventricle, interruption of the echo signal in the area of ​​the interatrial septum and the presence of an enlarged cavity of the left ventricle.

The X-ray research program includes:
1. Catheterization of the right atrium.
2 Catheterization of the left atrium and left ventricle (via interatrial communication).
3. Right atriography.
4. Left ventriculography.

One of the pathognomonic signs of cardiac catheterization in this pathology is the impossibility of passing a catheter from the right atrium into the right ventricle. The catheter easily passes through the interatrial communication into the left atrium and then into the left ventricle. When registering pressure curves, an increase in the maximum and average pressure in the right atrium is determined, the presence of a mean pressure gradient between the right and left atria, the magnitude of which depends on the size of the interatrial message.

Analysis gas composition blood reveals a decrease in blood oxygen saturation in the left atrium and severe arterial hypoxemia. Left ventriculography has importance to choose the method of surgical treatment. It allows you to assess the size of the ventricular septal defect, the degree of hypoplasia of the right ventricle, the size of the patent ductus arteriosus, the state of the collateral circulation and the nature of the damage to the pulmonary artery system. Right atriography allows you to assess the nature of the interatrial message.

At this study the dimensions of this message are determined in the lateral projection or in the projection of "4 chambers" according to the width of the jet of contrast agent coming from the right atrium to the left. It is important to note that the right atriography reveals a pathognomonic sign of defect in the anteroposterior projection: an uncontrasted triangular area located at the site of the inflow part of the right ventricle between the contrasted right atrium and left ventricle. Indications for palliative surgery are determined by the size of the interatrial communication, the state of the pulmonary blood flow.

Angiocardiogram of a patient with atresia of the right atrioventricular orifice. Right atriogram in anteroposterior projection. The contrasted blood, bypassing the right ventricle, enters the left atrium, then into the left ventricle and aorta. In the projection of the hypoplastic right ventricle, an uncontrasted triangle is determined

Anesthesiological support

Currently, in patients in critical condition, in most cases, intubation anesthesia is used according to the methodology developed at the Institute of Agricultural Surgery named after A.I. A.N. Bakulev Academy of Medical Sciences of the USSR:
1. 10 mg/kg of ketamine, 0.1 mg/kg of seduxen and 0.1 ml of a 0.1% solution of atropine sulfate are injected intramuscularly.
2. After tracheal intubation through the nose, artificial ventilation of the lungs is carried out with a mixture of oxygen and nitrous oxide in a ratio of 1: 1, with severe hypoxemia, artificial ventilation of the lungs is carried out with 100% oxygen.

In cases where studies are carried out against the background of deep premedication and local anesthesia 0.5% solution of novocaine, 30 minutes before the study, patients are injected intramuscularly with Seduxen 0.3-0.5 mg / kg and subcutaneously 0.05-0.1 ml of a 0.1% solution of atropine sulfate. In the X-ray operating room, immediately before the study, 8-10 mg/kg of ketamine is administered intramuscularly. As a rule, these dosages are sufficient for the study. In some cases, when the patient is anxious, 4 mg/kg of ketamine or 0.25 mg/kg of seduxen is additionally administered through a diagnostic catheter or a catheter installed in peripheral vein for drip infusion.

Regardless of the anesthesia technique, adequate anesthetic management includes a number of necessary measures:
1. Intravenous administration 4% sodium bicarbonate solution at the rate of 1/3 BE x the patient's body weight to correct metabolic disorders.
2. Intravenous administration of 10% calcium gluconate solution, 10% solution calcium chloride, hormonal and antihistamines in age dosage- as a set of measures to protect the body from the toxic effects of a contrast agent.
3. Timely compensation for the slightest blood loss.
4. The use of heating pads or heating mattresses to prevent spontaneous hypothermia.

V.A. Gharibyan, B.G. Alekyan

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. In this case, the coronary vessel is filled through the expanded 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 type 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

AT modern 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 high blood pressure blood 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.

In tetralogy of Fallot with atresia, the patient needs urgent operation. 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.

Can be identified using 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 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;
• pass the genetic expertise if there were people with heart defects in the family.

These preventive measures significantly reduce the chances of developing in the unborn child serious violations in the construction of the SSS.