Truncus Arteriosus

Truncus arteriosus is a congenital (birth) heart defect where the blood vessel coming out of the heart in the developing infant doesn't separate completely. This leaves a connection between the aorta and pulmonary arteries.

Normally, the right side of the heart pumps blood that doesn't have enough oxygen to the lungs to become oxygenated. Then the left side of the heart pumps oxygen-rich blood to the rest of the body. In infants with a truncus arteriosus, this oxygen-poor blood and oxygen-rich blood get mixed because the aorta and pulmonary artery are still connected. Too much blood goes to the lungs, and the heart has to work harder to pump blood to the rest of the body.

With truncus arteriosus, there is also usually a hole between the bottom two chambers called a ventricular septal defect.

What happens once you have truncus arteriosus?

With truncus arteriosus, too much blood circulation in the lungs may cause extra fluid to build up in and around them. This makes it hard to breathe.

If left untreated, more than normal blood flows to the lungs for a long time and the lungs' blood vessels become permanently damaged. Over time, it becomes hard for the heart to force blood to them. This is called pulmonary hypertension, which can be life-threatening.

Infants with truncus arteriosus may have a bluish skin color (cyanosis) because their blood isn’t carrying enough oxygen. They can also have symptoms such as:

• Weak pulse.


• Poor feeding.


• Pounding heart.


• Problems breathing.


• Extreme sleepiness.

What causes truncus arteriosus?

The cause of truncus arteriosus, and other heart defects, is unknown. Congenital heart defects are thought to be caused by the combination of genes and other environmental factors such as things the mother breathes, eats, or drinks or certain medications she uses.

What types of tests are used to diagnose truncus arteriosus?

Infants with truncus arteriosus are usually in distress in the first few days of life because of the high amount of blood going to the lungs, making the heart work harder. These tests can diagnose the problem:

• Echocardiogram: This detailed ultrasound of the baby’s heart can show problems with the heart's structure, like a single large vessel coming from the heart, and if the blood is leaking back into the heart or moving through a hole between the ventricles.


• Pulse oximetry: This is a simple bedside test to determine the amount of oxygen in a baby’s blood. Pulse oximetry can identify truncus arteriosus before a newborn shows any symptoms.

What types of treatments and procedures are used to treat truncus arteriosus?

An infant with truncus arteriosus will likely need surgery soon after birth. The surgery is done to create a separate flow of oxygen-poor blood to the lungs and oxygen-rich blood to the body. How the surgery is done depends on how sick the child is and the structure of the defect.

The surgeon will close the hole between the bottom chambers of the heart (ventricular septal defect), usually with a patch. Then they will use the original single blood vessel to create a new aorta to carry oxygen-rich blood from the left ventricle out to the body. Finally, they will use an artificial tube with an artificial valve to connect the right ventricle to the arteries going to the lungs to carry oxygen-poor blood to the lungs.

Some infants with truncus arteriosus will need to take medicines. These can strengthen the heart muscle, lower their blood pressure, and help the body get rid of extra fluid.

Some infants with truncus arteriosus might not eat enough to gain weight because they are too tired. To make sure these infants have enough nutrition, they may be prescribed a high-calorie formula. Some babies might need a feeding tube temporarily.

What can I do to support my infant's health when they have truncus arteriosus?

Most infants with truncus arteriosus survive the surgery. However, they may need more surgery or other procedures as they get older. For example, the artificial tube doesn’t grow, so it will need to be replaced as the child grows. There also may be blockages to blood flow which may need to be relieved, or problems with the truncal valve.

A person born with truncus arteriosus will need regular follow-up visits with a cardiologist (a heart doctor) to check how well they are doing and avoid other health problems.

Why choose Presbyterian for truncus arteriosus?

Presbyterian’s Pediatric and Congenital Cardiology team has many different options to help you manage your or your child’s heart condition. The team performs various diagnostic tests and procedures to help form an accurate diagnosis and create individualized treatment plans. Depending on the type of heart condition your child has and its underlying cause, the team can recommend a wide variety of treatment options. Our pediatric cardiologists, pediatric interventional cardiologists, and pediatric cardiovascular surgeons work closely together for cases in which cardiac repair or surgery is the best treatment option.