What to do about the right aortic arch in the fetus. Right-sided position of the aortic arch

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If the right IV branchial arch is preserved after birth, right aortic arch. Identified as the only anomaly, and also in combination with a mirror arrangement of the organ, with. With this anomaly, the ascending aorta goes up and to the right from the trachea and esophagus, spreads over the right bronchus, and goes down either to the right or, passing behind the esophagus, to the left of the spine. The right-sided aorta often manifests itself without pathological symptoms. In these cases, the arterial ligament is located in front of the trachea and is not stretched, and if it passes behind the esophagus, it can be long. If the ligamentum arteriosus or patent ductus arteriosus passes from the pulmonary artery to the aorta to the left of the trachea and behind the esophagus, a ring is formed surrounding the esophagus and trachea. The arterial ligament presses on the esophagus and trachea. The left subclavian artery in one case passes in front of the trachea or diverticulum of the residual IV of the left branchial arch. The diverticulum is located at the junction of the right arch with the descending aorta. Diverticula are remnants of the left IV branchial arch with various options for the origin of the subclavian arteries.

Clinical symptoms

In children, a right-sided aortic arch can cause persistent hiccups. In the absence of a constricting ring closed by an arterial ligament, the course of the disease is asymptomatic. In adults with aortic sclerosis, the symptoms of dysphagia intensify. Respiratory disorders worsen after eating.

Varieties described in the literature

The aortic arch crosses the right main bronchus and descends the right side of the spine as the descending aorta. The left common carotid and left subclavian arteries depart from the innominate artery. The ligamentum arteriosus attaches to the innominate artery.

The right-sided aortic arch is located in the neck, at the level of the thyroid cartilage, on the right side of the larynx. The aortic arch is formed in this case from the third pair of the right branchial arch. The patent ductus arteriosus enters the descending aorta opposite the left subclavian artery. The left common carotid artery arises from the ascending aorta and ascends anteriorly and to the left of the trachea. The ductus arteriosus is involved in a vascular ring that compresses the trachea and esophagus.

1. X-ray data. When inhaling - insufficient aeration of the lungs, when exhaling - hyperaeration. Signs of infection in the lungs. The protrusion of the aorta is visible on the right side of the mediastinal shadow, and on the left the normal shadow of the aortic arch is absent. On the left side there is often a shadow image of a diverticulum located where the aortic bulge would normally be. The descending aorta is sometimes displaced towards the pulmonary fields. In the first oblique position, the trachea is shifted forward, and the shadow of the diverticulum is detected at the level of the arch between the trachea and the spine. In the left oblique position, the descending aorta bends. Lateral radiographs show a trachea filled with air in the upper normal part and clearly narrowed in the lower part.
2. Esophageal examination. A barium swallow reveals a sharp narrowing of the esophagus and compression of its left lateral and posterior surface, if there is a diverticulum or an arterial ligament in a closed ring. Above the notch on the posterior surface of the esophagus, a separate defect running obliquely upward and to the left is determined. It is caused by compression of the left subclavian artery, which passes behind the esophagus to the left clavicle. The shadow of the left subclavian artery, passing behind the esophagus, is located above the shadow of the right aortic arch. A pulsating left aortic diverticulum is seen posterior to the esophagus. The esophagus is displaced anteriorly.
3. Examination of the trachea with lipidol. If there are symptoms of tracheal compression, a contrast study of it shows the localization of the aortic ring. The introduction of lipoidol into the trachea reveals an elongated notch along the right wall of the trachea, caused by the adjacent aortic arch, a notch on the anterior wall of the trachea from compression by the pulmonary artery, and a depression on the left wall of the trachea - from the ligament arteriosus. If there is no compression of the trachea, then there is no point in examining it with lipidol.
4. Angiocardiography. It is produced when a right-sided aortic arch is combined with other congenital heart defects.

Differential diagnosis

A right-sided aortic arch can cause a picture similar to that observed with. In the anterior image, the right-sided aortic arch in children in the presence of an enlarged shadow of the thymus gland is not clearly visible. However, the gland does not move the esophagus forward. Tumors in the posterior portion of the superior mediastinal shadow may simulate the right aortic arch, but they do not pulsate. The normal prominence of the aortic arch on the left is preserved. With aneurysms of the innominate artery or left descending aorta, a shadow of the descending aorta is always detected.

Bend of the aortic arch to the right. A variant of the defect, in which the descending aorta is located to the right of the spinal column, is often combined with other defects in the development of the heart. It occurs in approximately 20% of patients with tetralogy of Fallot and often with the common truncus arteriosus. When there is a bend of the aortic arch to the right that is incompatible with other anomalies, there are no symptoms. It can be seen on an x-ray. When contrasting the esophagus, a depression of its right contour is noted at the level of the aortic arch.

Vascular ring. Congenital anomalies in the structure of the aortic arch and its main branches lead to the formation of vascular rings around the trachea and esophagus, compressing them to varying degrees. The most common:

1) doubling of the aortic arch;

2) bending of the aortic arch to the right in combination with the left arterial ligament;

3) anomalous origin of the right subclavian artery, which in such cases represents the last large thoracic branch of the normally located aorta;

4) localization of the site of origin of the innominate artery from the aortic arch to the left than compared to the norm;

5) the beginning of the left carotid artery is to the right compared to the norm and its localization is anterior to the trachea;

6) accessory left pulmonary artery.

The latter arises either from the trunk of the pulmonary artery, which is longer than usual, or from the right pulmonary artery. It passes between the trachea and esophagus, squeezing them.

The clinical picture is extremely variable. In some cases, especially with an anomalous origin of the right subclavian artery, there are no symptoms. When the trachea and esophagus are compressed by a vascular ring, it often appears in infancy. Breathing is stridorous in nature and intensifies when the child cries, during feeding, and when the head is tilted. Leaning your head back makes breathing easier. Vomiting often occurs, there may be a cough with a metallic tint, and pneumonia is not uncommon. X-ray examination of the patient with contrasting of the esophagus and aortography allows us to establish a diagnosis.

Surgical treatment is indicated for patients who have clinical signs of anomaly and radiographic signs of compression of the trachea or esophagus. When doubling the aortic arch, the vessel lying in front is usually dissected. In case of compression caused by the right aortic arch and the left arterial ligament, the latter is dissected. The abnormal right subclavian artery is ligated at its origin from the aorta. Since the abnormally originating innominate or carotid artery cannot be ligated, the tracheal compression they cause is eliminated by attaching the adventitia of these vessels to the sternum. Correction of the anomalous origin of the left pulmonary artery is carried out under conditions of artificial circulation by ligating the artery at the site of its origin, bringing it anterior to the trachea and reattaching it to the trunk of the pulmonary artery. Concomitant severe tracheomalacia worsens the prognosis.

The right aortic arch in the fetus is a congenital heart defect, which can occur alone or be combined with other, sometimes severe, defects. In any case, during the formation of the right arch, disturbances in the normal development of the fetal heart occur.

The aorta is the largest vessel in the human body, the function of which is to move blood from the heart to other arterial trunks, up to the arteries and capillaries of the whole body.

Phylogenetically, the development of the aorta undergoes complex changes during evolution. Thus, the formation of the aorta as an integral vessel occurs only in vertebrates, in particular in fish (two-chamber heart), amphibians (two-chamber heart with an incomplete septum), reptiles (three-chamber heart), birds and mammals (four-chamber heart). However, all vertebrates have an aorta, into which arterial blood mixed with venous, or entirely arterial, flows.

During the process of individual development of the embryo (ontogenesis), the formation of the aorta undergoes changes as complex as the heart itself. Starting from the first two weeks of embryo development, there is an increased convergence of the arterial trunk and the venous sinus, located in the cervical part of the embryo, which subsequently migrated more medially, towards the future thoracic cavity. The arterial trunk gives rise not only to two ventricles subsequently, but also to six branchial (arterial) arches (six on each side), which, as they develop, within 3-4 weeks, are formed as follows:

• the first and second aortic arches are reduced,
• the third arch gives rise to the internal carotid arteries that supply the brain,
• the fourth arch gives rise to the aortic arch and the so-called “right” part,
• the fifth arc is reduced,
• the sixth arch gives rise to the pulmonary trunk and the arterial (Botallov) duct.

The heart becomes completely four-chambered, with a clear division of the cardiac vessels into the aorta and pulmonary trunk, by the sixth week of development. A 6-week embryo has a fully formed, beating heart with large vessels.

After the formation of the aorta and other internal organs, the topography of the vessel looks like this. Normally, the left aortic arch begins from the aortic bulb in its ascending part, which, in turn, originates from the left ventricle. That is, the ascending part of the aorta passes into the arch approximately at the level of the second rib on the left, and the arch bends around the left main bronchus, heading posteriorly and to the left. The uppermost part of the aortic arch projects onto the jugular notch just above the upper part of the sternum. The aortic arch goes down to the fourth rib, located to the left of the spine, and then passes into the descending part of the aorta.

In the case when the aortic arch “turns” not to the left, but to the right, due to a failure in the formation of human vessels from the branchial arches of the embryo, they speak of a right-sided aortic arch. In this case, the aortic arch extends through the right main bronchus, and not through the left, as it should normally be.

Why does vice occur?

Any malformation is formed in the fetus if a woman is influenced by negative environmental factors during pregnancy - smoking, alcoholism, drug addiction, ecology and unfavorable background radiation. However, genetic (hereditary) factors play an important role in the development of the child’s heart, as well as existing chronic diseases in the mother or past infectious diseases, especially in the early stages of pregnancy (influenza, herpes infection, chickenpox, rubella, measles, toxoplasmosis and many others) .

But, in any case, when any of these factors influence a woman in the early stages of pregnancy, the normal processes of ontogenesis (individual development) of the heart and aorta, formed during evolution, are disrupted.

So, in particular, the period of pregnancy of approximately 2-6 weeks is especially vulnerable to the fetal heart, since it is at this time that the aorta is formed.

Classification of the right-sided aortic arch

variant of the right aortic arch with the formation of a vascular ring

Depending on the anatomy of the duct anomaly, there are:

1. The right aortic arch without the formation of a vascular ring, when the arterial ligament (overgrown arterial, or Botallov, duct, as it should be normally after childbirth) is located behind the esophagus and trachea,
2. The right arch of the aorta with the formation of a vascular ring, code arterial ligament, or patent ductus arteriosus, is located on the left of the trachea and esophagus, as if surrounding them.
3. As well as a separate similar form, the double arch of the aorta is distinguished - in this case, the vascular ring is formed not by the connective ligament, but by the inflow of the vessel.

Figure: a variety of options for the atypical structure of the aortic arch

Depending on whether any other structures of the heart were damaged during its formation, the following types of defect are distinguished:

1. An isolated type of defect, without other developmental anomalies (in this case, if the right-sided aorta is not combined with the DiGeorge syndrome characteristic of it in some cases, the prognosis is as favorable as possible);
2. In combination with (mirror, right position of the heart and great vessels, including the aorta), (which is also usually not dangerous),
3. In combination with a more serious heart defect - in particular (aortic dextraposition, ventricular septal defect, pulmonary stenosis, right ventricular hypertrophy).

Tetralogy of Fallot combined with the right arch is an unfavorable development option

How to recognize a vice?

Diagnosis of the defect is not difficult even during pregnancy. This is especially true in cases where the right aortic arch is combined with other, more severe anomalies of heart development. However, to confirm the diagnosis, a pregnant woman is repeatedly examined, including with expert-class ultrasound machines, and a council of geneticists, cardiologists and cardiac surgeons is assembled to make a decision on the prognosis and the possibility of delivery in a specialized perinatal center. This is due to the fact that with some types of defects combined with the right aortic arch, the newborn baby may require heart surgery immediately after delivery.

Regarding the clinical manifestations of the right aortic arch, it should be mentioned that an isolated defect may not manifest itself at all, only sometimes accompanied by frequent obsessive hiccups in the child. In the case of a combination with tetralogy of Fallot, which accompanies the defect in some cases, the clinical manifestations are pronounced and appear in the first days after birth, such as increasing pulmonary heart failure with severe cyanosis (blue discoloration of the skin) in the baby. That is why tetralogy of Fallot is classified as a “blue” heart defect.

What screening shows a defect in pregnant women?

The diagnosis of a right-sided aortic arch can be made already at the first screening, that is, at 12-13 weeks of pregnancy. More accurate information about the condition of the fetal heart can be obtained at the second and third screening ultrasound examinations (20 and 30 weeks of pregnancy).

An analysis of fetal DNA can further clarify the absence of a connection between the formation of a right-sided aorta and severe genetic mutations. In this case, chorionic villus material or amniotic fluid is usually collected through a puncture. First of all, DiGeorge syndrome is excluded.

Treatment

In the event that the right aortic arch is isolated and is not accompanied by any clinical manifestations after the birth of the child, the defect does not require surgical treatment. All you need is a monthly examination by a pediatric cardiologist with regular (every six months - once a year) ultrasound of the heart.

When combined with other heart defects, the type of surgical intervention is selected based on the type of defect. Thus, with tetralogy of Fallot, surgery is indicated in the first year of a child’s life, carried out in stages. At the first stage, palliative (auxiliary) shunts are applied between the aorta and the pulmonary trunk to improve blood flow into the pulmonary circulation. At the second stage, open heart surgery is performed using a cardiopulmonary bypass machine (ACB) to eliminate pulmonary stenosis.

In addition to surgery, cardiotropic drugs that can slow the progression of chronic heart failure (ACE inhibitors, diuretics, etc.) are prescribed for auxiliary purposes.

Forecast

The prognosis for an isolated right-sided aortic arch is favorable, since in most cases surgical intervention is not even required. So, in general, we can say that an isolated right aortic arch is not life-threatening for the child.

With combined types, the situation is much more complicated, since the prognosis is determined by the type of concomitant heart defect. For example, With tetralogy of Fallot, the prognosis without treatment is extremely unfavorable, unoperated children with this disease usually die in the first year of life. After surgery, the duration and quality of life increase, and the prognosis becomes more favorable.