Large vessel abnormality

Anomaly of the great vessels. In medicine, transposition of the great vessels (TGV) refers to a group of congenital heart defects in which there is an abnormal arrangement of the main blood vessels that leave the heart: the superior and / or inferior vena cava. , the pulmonary artery, pulmonary veins, and aorta. If only the arteries (pulmonary artery and aorta) are affected, the disorder is known as transposition of the great arteries.

Important and diagnosable syndromes are observed in the child , caused by the abnormal development of the aortic arch and the aberrant position of one or more vessels originating from it. Early diagnosis is of utmost importance , because early surgical intervention saves life and prevents many cases of serious illness .

Many insignificant aberrations of the origin and course of the intrathoracic arteries go unnoticed, since, despite their abnormal location, they do not compress the trachea or esophagus .

Summary

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  • 1 Etiology
  • 2 Frequency
  • 3 Diagnosis
    • 1 Roentgenological diagnosis
  • 4 Forecast
  • 5 Treatment
  • 6 Sources

Etiology

The development of the aortic arch is carried out by a series of evolutions of the even primitive aortic arches.

Frequency

There are many such abnormalities, but only a minority of them cause symptoms. The most common disorder in this symptomatic group is the double aortic arch. Wolman, in his remarkable communication of 1939 , could already find 6 cases in the medical literature.

It may well be conjectured that more than 100 cases have been operated in North America alone since that date. The right aortic arch is also not uncommon, but there is still a higher proportion of cases that do not produce symptoms. They only cause manifestations when the surrounding ring is completed with a patent ductus arteriosus , with an arterial ligament, or with another aberrant vessel.

Diagnosis

The signs and symptoms caused depend on the location of the aberrant vessel or vessels and the compression produced in the esophagus and trachea. In the double aortic arch, a combination of respiratory and digestive signs can be expected, with a predominance of respiratory signs. There dyspnea from birth, or presents only the several weeks. Stridulous respiration is observed in most cases, although expiratory stridency is heard more often than inspiratory. Stridor often persists during sleep and is intensified by crying. There may be permanent or episodic cyanosis .

Diet tends to initiate or intensify stridor, and to cause or increase dyspnea and cyanosis. The bottle is often poorly swallowed , and regurgitation may occur. The vomit sometimes contains fresh or altered blood . The food can also stimulate paroxysmal cough. All signs are aggravated by respiratory infections that repeatedly attack these children. During infections intense dyspnea and false croup may occur, signs that indicate acute laryngotracheobronchitis. In severe cases, children prefer to lie down and with the head at maximum extension, since the flexion of the neckintensifies dyspnea. The metallic voice is typical.

The right aortic arch itself produces few or no symptoms. Rarely, as it is directed to the right instead of the left, it compresses the trachea or the right pulmonary bronchi . In this case, compression produces atelectasis or pulmonary emphysema , or both. It most often causes the disorder when it constitutes a branch of a complete vascular ring and the others are a patent ductus arteriosus, a ligament, or a right subclavian artery. The vascular ring is not clinically different from a double aortic arch.

The most frequent anomaly of a single vessel is observed in the left subclavian artery with an aberrant origin on the right side of the arch and the path from it to the left side. It usually crosses behind the esophagus, less often between the esophagus and trachea, or, rarely, in front of the trachea. If symptoms occur, they may be limited to dysphagia , but if one of the two less frequent routes is followed, respiratory symptoms may also occur.

The presence of respiratory symptoms without esophageal symptoms suggests that the trachea is compressed by an abnormal innominate artery. There may be no symptoms or signs at birth, and yet they appear and intensify in the first months of life, only to disappear later. Episodes of apnea , laxity and cyanosis are possible in these circumstances , as in other forms of tracheal compression, caused by aberrant vessels.

Roentgenological diagnosis

Normalized atelectasis or emphysema of the newborn , if persistent, should suggest vascular compression of a main bronchus. Exposure of the trachea in current anteroposterior and lateral views reveals a stenosis above the carina, in addition to one of a deviation towards the horizontal or sagittal plane. The most effective procedure for diagnosis is the esophagogram, after swallowing the barium , which shows the abnormalities of the esophageal contour. The use of high voltages in the impression of the films, intensifies the contrast between the air and the soft tissues and helps to identify a tracheal compression.

When the esophagus is filled with barium, its forward deflection is observed by a pulsating, spherical body. Instant, localized roentgenograms reveal constriction from both sides, and in the lateral view, show deep depression in front and behind. The aberrant right subclavian artery with the usual path from left to right produces an oblique defect on the posterior aspect of the esophagus, with a width of approximately 0.5 cm and a length of 3 to 4 cm.

Tracheograms and contrast angiograms are not indicated, except in rare cases where current roentgenograms and esophagograms are not sufficient to establish the suspected diagnosis. They are useful to the surgeon by indicating if the anterior or posterior arch is better, thus deciding which one should be ligated. The incision used may depend on this information.

Forecast

The prognosis varies depending on the degree of tracheal obstruction, the nature of the abnormality, and the treatment instituted. Children with early symptoms will be carefully observed, because often, along with development, strangulation of the ring increases. Sudden death can occur. Infections of the lower respiratory tract, sometimes pneumonia , are frequently observed , but in most cases, conditions resembling severe laryngotracheobronchitis. After surgical correction, even if dyspnea quickly disappears, stridor is likely to persist for many months.

Treatment

Surgical correction has been successfully achieved in all types of ring-shaped vascular abnormalities. The surgical risk is still great. In choosing the appropriate time of operation, the surgical hazard should be compared with the degree of respiratory distress. If it is serious from the beginning, the operation is indicated in the neonatal period. If the operation can be deferred, all respiratory infections will be treated promptly and vigorously with antimicrobial agents.

The most frequent problem that occurs in the postoperative period is the persistence of the respiratory disorder once the obstruction vessel has been excised. Often, when the trachea cannot be restored to its normal dimensions, this is due to the existence of hypoplastic segments of the trachea, which frequently require subsequent intervention. In some cases, supports made from an autologous rib have been used in cases of symptomatic tracheomalacia. In certain circumstances, a tracheostomy is essential

 

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