Transposition of the Great Arteries (TGA)

Transposition of the great arteries (TGA) is a rare birth condition that affects how the heart is connected to the lungs and body.

Normally, the right side of the heart pumps blood into the lungs, where it receives oxygen. The left side of the heart then pumps this oxygen-rich blood to the rest of the body. The blood follows this important path thanks to two arteries or “great vessels,” the pulmonary artery and the aorta. The pulmonary artery is connected to the right side of the heart, and the aorta is connected to the left side.

But in TGA, the arteries’ connections are reversed: The pulmonary artery is connected to the left side of the heart, and the aorta is connected to the right side. This causes blood to flow through the heart and lungs in the wrong direction, resulting in something called “parallel circulation.” Instead of sending blood that’s low in oxygen to the lungs, the right side of the heart sends it directly out to the body. Meanwhile, the left side of the heart sends blood that already has enough oxygen back to the lungs.

As a result, the body never gets the oxygen-rich blood that it needs.

Patients with TGA may also have a hole in the heart known as a ventricular septal defect (VSD), or other heart problems. In extreme cases, patients may have a single ventricle anatomy, meaning that only one side of their heart is functioning properly.

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What Are the Signs and Symptoms of Transposition of the Great Arteries?

TGA is often detected before birth, or in the first days of a baby’s life. Here are common signs of TGA in infants:

  • Bluish or grayish lips, skin and nails
  • Trouble breathing
  • Trouble feeding
  • Poor weight gain
  • Low energy and activity

At Connecticut Children’s, we can diagnose many congenital heart problems in utero before babies are even born. We work with our award-winning neonatologists, fetal cardiologists, the mother’s labor and delivery doctors, and our other pediatric specialists to plan ahead for the birth and the important moments that follow.
 

What Causes Transposition of the Great Arteries?

TGA is a condition that occurs before birth, when the great vessels (the aorta and pulmonary artery) don’t attach in the correct position to the heart during pregnancy.

For some babies, TGA may be linked to genetic condition like DiGeorge syndrome. For others, there is no known cause.

How is Transposition of the Great Arteries Treated?

Usually, babies with TGA need surgery within a few days of being born.

  • Before surgery, supplemental oxygen or a machine to help the baby breathe
  • Before surgery, medication to help the baby’s heart and lungs work better
  • Before surgery, balloon atrial septostomy: Uses a long, thin tube (catheter) to place a balloon in a natural hole in between the upper chambers of the heart. This enlarges the hole and allows blood from both sides of the heart to mix, which results in more oxygen-rich blood going to the body

Arterial switch operation: Surgery to connect the aorta and pulmonary artery to the correct sides of the heart

Like many patients with congenital heart defects, patients born with TGA have a unique anatomy. So it’s important that, throughout their life, they continue to get care from congenital heart experts, understand how their heart was reconstructed in surgery, and how it functions today.

Connecticut Children’s Heart Center provides this expertise at locations close to home, including access routine care like echocardiograms. We’re proud to stay with patients as they grow into adult care, too, with our nationally accredited Adult Congenital Heart Disease program.

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