dextro-Transposition of the great arteries (d-Transposition of the great arteries, dextro-TGA, or d-TGA) is a potentially life-threatening birth defect in the large arteries of the heart. The primary arteries (the aorta and the pulmonary artery) are transposed.It is called a cyanotic congenital heart defect (CHD) because the newborn infant turns blue from lack of oxygen. In segmental analysis, this condition is described as ventriculoarterial discordance with atrioventricular concordance, or just ventriculoarterial discordance. d-TGA is often referred to simply as transposition of the great arteries (TGA); however, TGA is a more general term which may also refer to levo-transposition of the great arteries (l-TGA).Another term commonly used to refer to both d-TGA and l-TGA is transposition of the great vessels (TGV), although this term might have an even broader meaning than TGA. Prenatally, a baby with d-TGA experiences no symptoms as the lungs will not be used until after birth, and oxygen is provided by the mother via the placenta and umbilical cord; in order for the red blood to bypass the lungs in utero, the fetal heart has two shunts that begin to close when the newborn starts breathing; these are the foramen ovale and the ductus arteriosus. The foramen ovale is a hole in the atrial septum which allows blood from the right atrium to flow into the left atrium; after birth, the left atrium will be filled with blood returning from the lungs and the foramen ovale will close.
When no other heart defects are present it is called simple d-TGA; when other defects are present it is called complex d-TGA.Although it may seem counterintuitive, complex d-TGA presents better chance of survival and less developmental risks than simple d-TGA, as well as usually requiring fewer invasive palliative procedures. This is because the left-to-right and bidirectional shunting caused by the defects common to complex d-TGA allow a higher amount of oxygen-rich blood to enter the systemic circulation. However, complex d-TGA may cause a very slight increase to length and risk of the corrective surgery, as most or all other heart defects will normally be repaired at the same time, and the heart becomes "irritated" the more it is manipulated. Treatment
Life-saving heart surgery is always required. If the diagnosis is made in a standard hospital or other clinical facility, the baby will be transferred to a childrens hospital, if such facilities are available, for specialized paediatric treatment and equipment. The patient will require constant monitoring and care in an intensive care unit (ICU). Palliative
Palliative treatment is normally administered prior to corrective surgery in order to reduce the symptoms of d-TGA (and any other complications), giving the newborn or infant a better chance of surviving the surgery.