Transposition of the great arteries

Transposition of the great arteries (TGA), also known as transposition of the great vessels, is one of the most common cyanotic congenital cardiac conditions in infancy. It occurs when the aorta and pulmonary arteries are in the wrong position, which causes oxygen-rich blood to go back to the lungs and oxygen-deprived blood to go to the body.

TGA occurs in the womb when your baby’s heart is developing. Since this disorder deprives the organs of much needed oxygen, it must be treated immediately with medication and/or intervention for the infant to survive. Effects of untreated TGA can include:

• Hypoxia, or insufficient oxygen flow to tissues. This typically leads to death unless there is some presence of oxygenated blood within the infant’s body.
• Heart failure, resulting from the right ventricle working in overdrive to deliver enough oxygen to the rest of the body. 

If a baby is born with TGA, he or she will exhibit the following symptoms:

• Blue skin, also known as cyanosis
• Shortness of breath
• Poor weight gain
• Lack of appetite

Transposition of the great arteries is typically diagnosed upon birth and in the first few weeks of life. However, it can also be diagnosed prenatally, and prenatal diagnoses often produce the best outcomes. 

All cases of TGA require early surgery, usually within the first week of your baby’s life. This treatment is usually done in steps.

When babies are born with transposition of the great arteries, it is necessary that the oxygenated blood coming from the lungs mixes with the less oxygenated blood coming from the rest of the body. If the baby does not have adequate openings in the walls that separate the left and right side of the heart, a balloon atrial septostomy may be required. This is a type of heart procedure known as a cardiac catheterization. In this procedure, a tube or a catheter is inserted through the baby’s veins and advanced into the top left chamber of the heart. The balloon is then pulled through to make the hole bigger and allow oxygen-rich and oxygen-poor blood to mix better. This procedure is usually done either in the neonatal intensive care unit or in the cardiac catheterization area of the hospital.

After the baby is stabilized, the surgical team completes the arterial switch operations where the two great arteries are switched to their proper positions coming from the heart. In general, babies who have had these procedures will be in the hospital for a couple of weeks after the heart surgery, and will then follow up with their cardiologist as they grow for any problems that might arise. While this is a serious heart problem, most babies who have transposition of the great arteries can be expected to do very well.