Heart and Blood Conditions

Truncus Arteriosus

What is truncus arteriosus?

Truncus arteriosus (pronounced TRUN-kus ar-teer-ee-OH-sus) is a rare birth defect in which only one large artery leaves the heart.

Normally, two large arteries leave the heart — the aorta, which carries oxygen-rich (red) blood to the body, and the pulmonary artery, which carries oxygen-poor (blue) blood to the lungs.

In babies with this condition, the aorta and pulmonary artery are joined. They form a large common artery, called the truncus arteriosus, or trunk. The arteries to the lung (pulmonary arteries) branch off from this trunk.

There are four different types of truncus arteriosus (types I to IV). The type depends on the position of the pulmonary arteries, and whether they developed as a single artery or several arteries. Your doctor will consider the type of truncus arteriosus your child has when recommending which kind of surgery is needed, and when.

These babies also have a hole in the septum between their left and right ventricles. This hole is known as a ventricular septal defect. The hole allows oxygen-rich blood from the left ventricle to mix with oxygen-poor blood from the right ventricle.

The mixed blood enters the trunk and goes out to both the body and the lungs. This explains why a baby with this condition may be blue (cyanotic). Some of the blood going out to their body does not have oxygen.

The other main problem is that the lungs may get too much blood. This makes breathing hard, and it can lead to high blood pressure in the lungs and heart failure.

Truncus Arteriosus in Children

Before birth, it’s normal for babies to have one common artery leaving their heart. As they develop, this common artery should divide into an aorta and a pulmonary artery. It’s not clear why the common artery does not divide the way it should in some babies.

Truncus Arteriosus at Seattle Children’s

Our heart team has treated many children with truncus arteriosus. We have extensive experience with the surgery these patients require. We also have a pediatric cardiac anesthesia team and a cardiac intensive care unit to help care for children who undergo heart surgery.

When you come to Children’s, a team of people will take care of your child. Along with your child’s heart doctor (cardiologist), you are connected with surgeons, newborn specialists (neonatologists), lung doctors (pulmonologists), nurses, child life specialists, social workers and others, if their expertise is needed. We work together to meet all of your child’s health needs and help your family through this experience.

Seattle Children’s has been treating children since 1907. Our team members are trained in their fields and in meeting the unique needs of children. For example, the doctors who give your child anesthesia (sedation) are board certified in pediatric anesthesiology. This means they have extra years of training in how to take care of kids. Our child life specialists know how to help children understand their illnesses and treatments in ways that make sense for their age.

The Adult Congenital Heart Disease Program shared by Children’s and the University of Washington can help with care throughout your child’s life.

Contact Us

Contact the Heart Center at 206-987-2015 for a cardiac referral, a second opinion or more information.