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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. This changes the way blood circulates through the body causing  and causes oxygen-poor blood flowing to the body.  

How is TGA diagnosed and monitored during pregnancy?

If your doctor suspects TGA after reviewing your routine ultrasound, he/she may request a fetal echocardiogram, or an ultrasound of the fetal heart. This echocardiogram shows the structures of the heart and how it is funtioning, which can help us confirm the diagnosis of TGA. After diagnosis, the Fetal Heart Team will continue to assess fetal well being for the remainder of the pregnancy. 

How does TGA affect delivery?

Most babies with TGA can be delivered vaginally at full term unless otherwise indicated by your Obstetrician. 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).

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.

How does the diagnosis of TGA affect my child after delivery?

After delivery, your baby will need prostaglandin (PGE), an intravenous medication that allows mixing of oxygenated and deoxygenated blood through a blood vessel present in every fetus before birth. The PGE prevents this blood vessel from closing at birth.  Your baby may also require a special procedure done in the pediatric hybrid cardiac catheterization suite at Cardinal Glennon to enlarge a hole between the top two chambers of the heart (the right and left atrium). During ths 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 helps improve the mixing of blood.

What are the treatments and surgeries for TGA?

Medical treatment with PGE is required for all babies with TGA.

The surgical approach for TGA depends on the baby’s anatomy. The most common procedure is the arterial switch. In this open-heart surgery, the pulmonary artery and aorta are switched back to their normal positions.

For complex cases not amenable to the arterial switch, other options are considered. 

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 normal lives. They will need lifelong follow-up visits with a pediatric cardiologist.

In some cases children may develop narrowing of the pulmonary arteries, which might require further treatment.