Transposition of great vessels

Transposition of the great arteries (TGA) is a group of congenital heart defects (CHDs) involving an abnormal spatial arrangement of the primary arteries (pulmonary artery and aorta). It is a type of transposition of the great vessels, and was first described in 1797 by Matthew Baillie. more...

Description

In a normal heart, oxygen-depleted ("blue") blood is pumped from the right side of the heart, through the pulmonary artery, to the lungs where it is oxygenated. The oxygen-rich ("red") blood then returns to the left heart, via the pulmonary veins, and is pumped through the aorta to the rest of the body, including the heart muscle itself.

Transposed arteries can present a large variety of ventriculoarterial and arteriovenous discordance. The effects may range from a change in blood pressure to an interruption in circulation, depending on the nature and degree of the misplacement and the presence or absence of other defects.

Variations and Similar Defects

TGA may be defined as either dextro-TGA (d-TGA) or levo-TGA (l-TGA). With d-TGA, the aorta is anterior and to the right of the pulmonary artery, creating two separate, “circular” circulatory systems; with l-TGA, the aorta is anterior and to the left of the pulmonary artery and is accompanied by transposed ventricles; this combination results in a “corrected” circulation.

Simple and Complex TGA

TGA is often accompanied by other heart defects, the most common type being intracardiac shunts such as atrial septal defect (ASD) including patent foramen ovale (PFO), ventricular septal defect (VSD), and patent ductus arteriosus (PDA). Stenosis, or other defects, of valves and/or vessels may also be present.

When no other heart defects are present it is called 'simple' TGA; when other defects are present it is called 'complex' TGA.

Similar Defects

The following defects also involve abnormal spatial arrangement and/or structure of the great arteries:

• Coarctation of the aorta
• Double outlet right ventricle (DORV)
• Left heart hypoplasia or hypoplastic left heart syndrome (HLHS)
• Overriding aorta
• Patent ductus arteriosus (PDA)
• Taussig-Bing syndrome
• Tetralogy of Fallot (TOF)
• Truncus arteriosus
• Vascular rings

External Links

• Information on Transposition of the Great Arteries from Seattle Children's Hospital Heart Center

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