Transposition of the great arteries

Classification according to ICD-10
Q20.3	Discordant ventriculo-arterial connection - transposition of the great vessels (complete)
ICD-10 online (WHO version 2019)

The transposition of the large arteries (TGA) is a congenital swapping of the vessels leaving the heart and, in the case of levo-TGA, also the incoming vessels. In the more common dextro-transposition of the great arteries (d-TGA), the aorta is connected to the right (anterior) and the pulmonary artery to that of the left (posterior) ventricle of the heart . The pulmonary and body circulation are therefore separate and the clinical picture is not compatible with life unless there are other malformations (for example an atrial septal defect ) and the ductus arteriosus Botalli is closed (usually occurs in the first days of life).

TGA occurs with 5% of congenital heart defects both as the sole malformation and in connection with a ventricular septal defect (VSD), additional pulmonary stenosis (narrowing of the pulmonary artery valve ) and other complex malformations and is the second most common cyanotic malformation of the heart. Since it is caused by a disturbed rotation of the outflow path of the heart in the embryonic development, it is a common symptom in the context of so-called heterotaxies .

Clinical picture

cyanotic newborn with TGA and VSD

In d-TGA, the main artery ( aorta ) and the pulmonary artery are reversed. They do not cross over as in a healthy heart, but rise in parallel. The aorta is fed by the right ventricle, the pulmonary artery by the left. The body and pulmonary circulation are not connected in series, but form two separate circuits. In the fetus in the womb, the blood is oxygenated in the placenta, so the lungs do not yet have a gas-exchanging function. If the fetal (prenatal) cross-connections close after the birth, the child is in a life-threatening state because the body and pulmonary circulation are now actually separated and the oxygen supply to the body is cut off. In more than half of the children, however, there is also another heart defect, such as B. a ventricular septal defect . This decides on the degree of cyanosis .

Diagnosis

• The echocardiography almost always provides a definitive diagnosis.
• A cardiac catheterization is only necessary in some cases to clarify further complications.

therapy

Medicinal and Interventional Therapy

As soon as the ductus arteriosus and foramen ovale close as part of normal postnatal development and thus prevent the passage of oxygen-rich blood from the pulmonary into the body circulation, attempts are made to keep the ductus arteriosus open with the active ingredient prostaglandin as a life-saving measure . Another option is to widen the foramen ovale with the Rashkind maneuver (tearing the atrial septum with a balloon catheter). An artificial atrial septal defect (ASD) develops .

Operations

The common operation of a d-TGA today is the arterial switch operation . It is carried out in the first days or weeks of life. The aorta and pulmonary artery are cut off just above the heart valves and sutured again, reversed (pulmonary artery anastomosis was mostly reconstructed using a pericardial patch). The coronary arteries must also be transplanted. In the postoperative period, supravalvular pulmonary stenosis was frequently observed. An existing ventricular septal defect (VSD) is closed. The circuit now corresponds to the anatomically correct course. Eliminating the pericardial pick for pulmonary artery reconstruction and using a direct connection reduced the incidence of this complication. The children usually develop normally and without complications.

Earlier surgical procedures were the almost identical Senning or Mustard atrial reversal surgical procedures . The atrial septum was removed and an artificial diversion of the venous blood was created at the atrial level so that the oxygen-rich blood enters the body's circulation. The aorta and pulmonary artery remained in the "wrong" place. This means that now, contrary to the natural circulation, the right heart pumps into the body circulation and the left into the pulmonary circulation. Many patients who have been operated on using these methods are doing well today. In the long run, however, cardiac arrhythmias may have to be expected, the tricuspid valve may leak and the right system ventricle may fail due to the high pressures it has to exert. Therefore, after sufficient and positive experience with the arterial switch operation, these operations are only carried out in very rare cases.

The principle of the Rastelli operation in a d-TGA with VSD and pulmonary stenosis is based on the fact that the left ventricle has to apply high pressure due to a narrowing in the lower part of the pulmonary artery and therefore the oxygen-rich blood coming from the lungs via the VSD in the aorta can flow. The circuits are separated at the level of the ventricles (heart chambers) by the insertion of a valve-bearing conduit and thus the functional closure of the VSD. The conduit may need to be replaced later depending on the age and timing of the operation. Because after this operation the left ventricle pumps the blood into the body's circulation and the right ventricle pumps the blood into the pulmonary circulation, it is also an anatomical correction. This surgical procedure is still used today for appropriate indications.

All operations are performed with the help of the heart-lung machine . Lifelong check-ups must be observed and endocarditis prophylaxis must also be taken into account.

Taussig-Bing complex

The Taussig-Bing complex is a very rare special form of TGA (a partial TGA):

• The aorta arises from the right ventricle
• The pulmonary artery "rides" over a ventricular septal defect and receives blood from both heart chambers

Consequences:

• The venous blood from the circulatory system flows through the right atrium into the right ventricle, then into the aorta and into the circulatory system.
• The oxygenated blood from the lungs flows through the left atrium into the left ventricle and then, for the greater part, through the "riding" pulmonary artery (which is connected to both the right and left ventricles) back into the lungs and, to a lesser extent, through the Ventricular septal defect into the right ventricle and then via the aorta into the circulatory system.
• The result is an overload of both the lungs and the right heart, which can lead to insufficiency of both organs.

This clinical picture is named after Helen B. Taussig (pediatrician and cardiologist) and Richard J. Bing (American surgeon).

Corrected transposition of the great arteries

In the corrected transposition of the large arteries and levo-transposition of the large arteries (l-TGA), the arteries run parallel, as described above, but the right and left ventricles are also swapped. The left atrium releases its blood, which it received through the swapped pulmonary artery, directly to the right ventricle. From there it flows via the swapped aorta and the body's circulation into the right atrium, which releases it into the left ventricle. The heart and lung circulation are thus separated, but the left ventricle maintains the pulmonary circulation and the much weaker right ventricle maintains the body circulation. After the birth, the children may initially appear to have a healthy heart. Additional heart malformations can complicate this clinical picture.

Painting position

One speaks of a malposition when both large arteries arise from one ventricle, corresponding to a double outlet right / left ventricle (DORV / DOLV). Since one artery is fed correctly and the other incorrectly, the incorrect term “transposition” is avoided here.

literature

• P. Martins, E. Castela: Transposition of the great arteries. In: Orphanet J Rare Dis. 2008 Oct 13; 3, p. 27. PMID 18851735 , PMC 2577629 (free full text)
• Thomas Borth-Bruhns, Andrea Eichler: Pediatric Cardiology . 1st edition. Springer, Berlin 2004, ISBN 3-540-40616-6 , pp. 197 ff .
• Reinhard Larsen: Anesthesia and intensive medicine in cardiac, thoracic and vascular surgery. (1st edition 1986) 5th edition. Springer, Berlin / Heidelberg / New York et al. 1999, ISBN 3-540-65024-5 , pp. 370–377.
• S2k guideline D transposition of the large arteries of the German Society for Pediatric Cardiology (DGPK). In: AWMF online (as of 2013)

Web links

Animated heart defect description of the TGA, transposition of the great arteries

Individual evidence

1. ↑ Jürgen Apitz (Ed.): [Pediatric Cardiology] . 1st edition. Steinkopf, Darmstadt 1998, ISBN 3-7985-1036-9 , p. 330 .
2. ↑ Kuroczyński W , Kampmann Ch, Peivandi AA, Hartert M, Knuf M, Heinemann MK, Vahl CF: Mid-term results of a modified arterial switch operation using the direct reconstruction technique of the pulmonary artery. Cardiology Journal, 2010, vol. 17, no. 6, pp. 574-579
3. ↑ Moll JJ, Michalak KW, Młudzik K, Moszura T, Kopala M, Moll M, Moll JA .: Long-term outcome of direct neopulmonary artery reconstruction during the arterial switch procedure. Ann Thorac Surg. 2012 Jan; 93 (1): 177-84
4. ^ EW Keck, G. Hausdorf (Ed.): Pediatric Cardiology . 5th edition. Urban & Fischer, Munich / Jena 2002, ISBN 3-437-21960-X , p. 215 .

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