What is transposition of the great arteries?
Babies diagnosed with transposition of the great arteries (TGA) (also sometimes known as transposition of the great vessels) are born with a heart defect in which the two main arteries going out of the heart — the pulmonary artery and the aorta — are switched in position (transposed). The exact cause is unknown.
In a normal heart, blood goes from the right side of the heart to the pulmonary artery and to the lungs, where it picks up oxygen. Then the blood goes to the left side of the heart, through the aorta, and out to the body. In babies with TGA, the blood goes from the heart to the lungs where it picks up oxygen, then goes back to the heart, then back to the lungs without ever going to the body. Blood from the body goes to the heart, then back to the body without ever picking up oxygen in the lungs.
How is TGA diagnosed?
Symptoms of TGA normally appear at birth or very soon afterward, and may include:
- Bluish-purple skin color
- Shortness of breath
- Trouble with feeding
While examining your baby, the doctor will first listen for a heart murmur with a stethoscope. If the doctor hears a heart murmur and your baby is showing symptoms of TGA, any or all of the following tests may be done to confirm the diagnosis:
- Cardiac catheterization: a procedure where a thin, flexible tube is inserted through a large artery and into the heart, allowing your doctor to see the flow of blood through your baby’s heart and blood vessels on an X-ray image. This procedure may also be used to create a hole between two of the heart’s chambers so that the blood can mix (balloon atrial septostomy).
- Chest X-ray: a painless test that creates pictures of the heart and lungs
- Electrocardiogram (EKG): a painless test that records the heart’s electrical activity
- Echocardiogram: a painless test that uses sound waves to create a moving picture of the heart
- Pulse oximetry: a painless test that shows how much oxygen is in the blood
How is TGA treated?
Initially, your baby will be given a medicine called prostaglandin through an intravenous (IV) line. This medicine helps keep a blood vessel called the ductus arteriosus open, which will allow the blood with the oxygen to mix with the blood without oxygen.
Shortly after birth, a surgery called an arterial switch procedure will be done to permanently correct the defect. The purpose of the surgery is to switch the great arteries back to their normal positions.
How will TGA affect my baby during and after surgery?
During surgery, your baby will be given general anesthesia, which means the baby will be comfortable and sleeping. After surgery, your baby will need to stay in a cardiac intensive care unit (CICU) for the first few days and may be connected to several tubes and wires to allow your baby’s doctor to best monitor the baby’s condition. Pain control will be used to make sure your baby is comfortable.
Most of the tubes and wires will be disconnected before your baby leaves the CICU, after which he or she will spend several more days in the hospital in a step down unit.
Your baby’s symptoms should improve after the surgery. Most babies who undergo arterial switch surgery go on to live normal lives.