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What is Transposition of the Great Arteries (TGA)?

Transposition of the great arteries (TGA) is a congenital heart defect, where the aorta and pulmonary artery are switched, or transposed. This changes the way blood circulates through the body and causes a shortage of oxygen-rich blood flowing to the body.

A baby with untreated TGA can survive for a short while without intervention, but TGA must be treated soon after birth, because the body cannot function without enough oxygenated blood. Surgery is usually performed in the first week of life.

How is TGA diagnosed and monitored during pregnancy?

The Fetal Heart Team can diagnose TGA through a fetal echocardiogram (ECHO), or an ultrasound of the fetus’ heart. After diagnosing TGA during your pregnancy, our team monitors your baby closely, and helps your family create a plan for delivery.

How does TGA impact delivery?

Most babies with TGA can be delivered by whatever route the mother desires, usually vaginally. It is best for these babies to be delivered at a medical center where there is immediate access to a team of pediatric cardiologists and neonatologists, along with an established NICU (Neonatal Intensive Care Unit).

After delivery, the baby will need PGE, a special medicine that gives a blood vessel between the aorta and pulmonary artery the ability to remain patent, or open, after birth, which allows for mixing of oxygen poor and oxygen rich blood. If there is an inadequate atrial communication an urgent balloon atrial septostomy may be needed to improve mixing of oxygenated and non-oxygenated blood. During this minimally invasive procedure, a small catheter with a balloon attached to the tip is used to enlarge the hole between the right and left atria. This hole also helps improve the oxygenation of the blood.

The Fetal Heart Program at the St. Louis Fetal Care Institute has the experience, facilities and technology to handle the most medically challenging deliveries. In the most severe cases the team can perform cesarean sections and EXIT procedures at SSM Cardinal Glennon Children’s Medical Center. The EXIT procedure allows the fetal and cardiothoracic surgeons to perform life-saving procedures on the baby before cutting the umbilical cord. If additional intervention is needed, the baby is next door to the pediatric operating room and the pediatric hybrid cardiac catheterization suite.

What is the surgery for TGA, and how does it work?

The surgical approach for TGA depends on the baby’s anatomy:

  • Arterial Switch Surgery: This is the most common surgery for TGA, usually performed in the first week of life. In this open-heart surgery, the pulmonary artery and aorta are switched—moved back to their normal positions. Then, the coronary arteries are reattached to the aorta. If your baby has a hole between the ventricles or atria of the heart, typically the surgeon will close this hole (though in some cases, if the hole is small, it will close on its own).
  • Rastelli Operation: For complex TGA with a ventricular defect (or hole) that is not amenable to the arterial switch procedure the Rastelli Operation can be done. This open-heart procedure involves closing the VSD, and placing a right ventricle to pulmonary artery (RV-PA) conduit (artificial tube) to supply blood flow to the lungs.

For complex cases not amenable to these surgeries, other options include atrial switch surgery or palliative surgeries used for single ventricle lesions.

What happens after the surgeries, and what is the long-term prognosis?

With early diagnosis and treatment, many children born with TGA live healthy and relatively normal lives. They will need regular follow-up visits with a cardiologist to monitor their progress, but most lead normal and healthy lives. Many can perform physical activities at a normal level.

In some cases, there may be other complications down the road, such as arrhythmias or narrowing of the pulmonary arteries, which would need further treatment. But in many cases, the initial surgery will be the only treatment your child needs.