Truncus Arteriosus

Nemours Cardiac Center at Nemours/Alfred I. duPont Hospital for Children

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Children’s heart conditions can’t be prevented, but a lot can be done to improve and often completely repair their hearts at any age. Thanks to advanced technology and the pediatric heart experts at the Nemours Cardiac Center (based at Nemours/Alfred I. duPont Hospital for Children), most children born with a heart problem — even newborns only hours or days old — can be quickly diagnosed and treated right when it matters the most. At the Cardiac Center, we specialize in early detection and repair of congenital heart defects (also often called, “congenital heart disease”).

If your child’s been diagnosed with truncus arteriosus, we’re here to ease your concerns, answer your questions, and give your child the best possible chance for a healthy future.

What Is It?

As the heart develops in the first few weeks of fetal life in the womb, the single blood vessel leaving the heart (called the “truncus arteriosus communis”) separates into two blood vessels:

  • the aorta (which delivers oxygen-rich blood from the left ventricle to the body)
  • the pulmonary artery (which delivers oxygen poor blood from the right ventricle to the lungs)

In babies with truncus arteriosus (also called a “persistent truncus arteriosus” or “common aorticopulmonary trunk”), this separation didn’t happen. The failed separation starts within the heart itself, creating a ventricular septal defect (or “VSD,” a hole in the wall — the “ventricular septum” — between the right and left ventricles).

Where there should be two separate valves (one between the left ventricle and the aorta, and one between the right ventricle and pulmonary artery) there’s one common “truncal” valve that connects both ventricles to the truncus arteriosus. And instead of two vessels, there’s only the one truncus arteriosus initially, though it will branch into the pulmonary artery (sending blood to the lungs) and the aorta (sending blood to the body).

The result of this defect is that the low-oxygen blood from the right ventricle and the oxygen-rich blood of the left ventricle mix together and are pumped to both the lungs and the body. The blood vessels in the lungs are exposed to much higher pressure than normal (because they’re connected to the blood vessels to the body which operate at higher blood pressures). There’s also increased blood flow through the lungs (because the resistance to blood flow, called the “pulmonary vascular resistance,” is lower in the lungs than in the body, where the resistance is called “systemic vascular resistance”).

How Does the Heart Normally Work?

When your child has a congenital heart defect, there’s usually something wrong with the structure of the heart. In order to understand your child’s condition, it can help to know how the heart should work normally.
Learn More About Normal Cardiac Anatomy »

Nemours’ experts at also offer these helpful resources to help both you and your child understand how the heart works:

How & When Is It Diagnosed?

Children with truncus arteriosus show signs of heart failure and low oxygen levels in the body (called “hypoxia”).

Heart failure symptoms include:
  • rapid breathing
  • rapid heart rate
  • poor ability to feed and lack of weight gain (also known as “failure to thrive”)

We can usually diagnose truncus arteriosus using an echocardiogram (or “echo”). An echo is a completely safe and painless test that uses ultrasound (sound waves) to build a series of pictures of the heart.

In the rare cases where a child with truncus arteriosus is older, we may perform a cardiac catheterization before having surgery. Catheterization involves inserting a thin plastic, flexible tube (called a “catheter”) into an artery and vein that lead to the heart. Cardiac catheterization is done under sedation with local anesthesia or under general anesthesia, depending on your child’s age and condition.

How & When Is It Treated?

Babies with truncus arteriosus will need corrective surgery as soon as the diagnosis is made. If left untreated, about 50 percent of children won’t survive their first month, so our Nemours Cardiac Center heart surgeons perform surgery to repair the defect as soon as possible.

Complete repair requires multiple parts:
  1. closing the ventricular septal defect
  2. separating the pulmonary artery from the trunk
  3. closing the hold remaining where the pulmonary artery was removed
  4. creating a connection between the right ventricle and pulmonary artery

The VSD is closed so that blood from the left ventricle is directed to the truncal valve. The truncal valve and common arterial trunk then functions as the aortic valve and aorta would normally — directing blood from the left ventricle to the body. A connection then needs to be constructed between the right ventricle and pulmonary artery. This is called a “right ventricle to pulmonary artery conduit” (or “RV-PA conduit”). This way, the two sides of the heart are separated from each other and the oxygenated and deoxygenated blood no longer mix. And, so, the baby’s circulation is returned to a normal pathway.

Learn More About Heart Surgery »

How Will It Affect My Child Long Term?

Nearly all children with truncus arteriosus will need additional operations as they grow into adulthood. Most commonly, since it can’t grow with the child, the right ventricle to pulmonary artery (or “RV-PA”) conduit will need to be replaced as it becomes too small. About half of children will require this procedure before they’re 5 years old, but nearly all will need it by age 14.

Children may also need additional procedures on the truncal valve. Although surgery fixes the circulation of blood, it doesn’t change the fact that the valve itself is abnormal. In children who have a  valve that functions well before surgery, only about 10 percent will eventually need the valve replaced. However, among children where the truncal valve leaked prior to surgery, about 50 percent will need the valve replaced within 10 years.

If your child has truncus arteriosus, know that at the Nemours Cardiac Center we’re here to give your child the very best, most comprehensive and compassionate care. Our goal is to guide your family, from start to finish, through your child’s heart defect journey — and to help your child live the healthiest, most fulfilling life possible.

Learn More About Congenital Heart Defects »

Why Choose Us

From our outcomes to our family-centered care, find out all of the reasons why your child’s heart will be in good hands at the Nemours Cardiac Center. Learn More »

Make an Appointment

(800) 416-4441

Insurance We Accept »

Information for Patients

Outpatient Services and Inpatient Units: (302) 651-6660

After 5 p.m. and Weekends:

Cardiac Intensive Care Unit: (302) 651-6644
General Inpatient Unit, 2B: (302) 651-6690


+1 (302) 651-4993

Stories From the Heart

Meet children treated in the Nemours Cardiac Center who know what it’s like to live with a heart problem.

Read Their Inspiring Stories »