Truncus Arteriosus

Truncus arteriosus is a rare congenital heart defect where only one large blood vessel leads out of the heart instead of two, and branches to form both the pulmonary arteries (taking blood to the lungs) and the aorta (taking blood to the body). There is also a hole in the wall (ventricular septum) between the bottom chambers of the heart (the right and the left ventricle). This hole is called a ventricular septal defect (VSD) and allows oxygenated and unoxygenated blood to mix together.

If your doctor suspects a fetal heart anomaly after reviewing your routine ultrasound, he or she may request a fetal echocardiogram (echo), an ultrasound of the fetus’s heart. This safe, noninvasive test shows the structure of the heart and how it is functioning, which can help us confirm the diagnosis of truncus arteriosus and discuss possible options for treatment after delivery. Our fetal heart team will monitor your baby closely for the remainder of the pregnancy.

How Does Truncus Arteriosus Affect Delivery?

Most babies with truncus arteriosus 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 access to a team of pediatric cardiologists and neonatologists, along with an established Neonatal Intensive Care Unit (NICU).

How is Truncus Arteriosus Treated?

Surgical repair of Truncus Arteriosus

Most babies with truncus arteriosus need surgery in the newborn period. There are several components of the repair:

• The pulmonary arteries are separated from the blood vessel leading out of the heart.
• An artificial pulmonary valve is placed between the right ventricle and the pulmonary arteries.
• The VSD is closed.
• The large blood vessel is left in place as the aorta.

After surgery your baby will require a stay in the Neonatal or Pediatric Intensive Care Unit (NICU or PICU) until they overcome any feeding and breathing difficulties. Your child will likely need lifelong follow-up visits with a cardiologist so the heart remains healthy.

Because the pulmonary valve is artificial and does not grow with your child, this valve will need to be replaced periodically. In some cases the truncal valve may become leaky or blocked and require replacement, as well. However, the long-term prognosis remains good.