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Truncus arteriosus

Medically reviewed by Last updated on Nov 12, 2022.


Truncus arteriosus (TRUNG-kus ahr-teer-e-O-sus) is a rare heart problem present at birth. That means it's a congenital heart defect. In this condition, one large blood vessel leads out of the heart, instead of two.

Having only one large blood vessel means that oxygen-poor and oxygen-rich blood mix. This mixing reduces the amount of oxygen delivered to the body. It usually increases the amount of blood flow into the lungs too. The heart has to work harder to adjust for the changes in blood flow.

A person with truncus arteriosus also usually has a hole between the two lower heart chambers, called the ventricles. The hole is called a ventricular septal defect.

Another name for truncus arteriosus is common arterial trunk.

Truncus arteriosus is a life-threatening condition. A baby with the condition needs surgery to repair the heart problems and fix blood flow. Surgery is generally successful, especially if done before the baby is 1 month old.

Truncus arteriosus

In truncus arteriosus, one large vessel comes out of the heart, instead of two separate ones. There's also usually a hole in the wall between the lower heart chambers, called the ventricles. The hole is called a ventricular septal defect. In truncus arteriosus, oxygen-rich blood, shown in red, and oxygen-poor blood, shown in blue, mix together. The mixed blood is shown in purple. It doesn't contain enough oxygen for the body's needs.


Symptoms of truncus arteriosus usually occur in the first few days of life. They include:

When to see a doctor

If you have concerns about your baby's feedings, sleep patterns or growth, contact your health care provider for an appointment.

Always seek emergency medical care if a baby has any of the following:


Truncus arteriosus occurs as a baby's heart forms during pregnancy. There's often no clear cause. Genetics and environmental factors may play a role.

How the heart works

To understand more about truncus arteriosus, it may be helpful to know how the heart typically works.

The typical heart is made of four chambers. They are:

A baby's heart before birth

The formation of a baby's heart is complex. At a certain point, babies in the womb have a single large blood vessel exiting the heart. The vessel is called the truncus arteriosus. It usually splits in two as the baby grows in the womb. One part becomes the lower end of the body's main artery, called the aorta. The other part becomes the lower part of the pulmonary artery.

But in some babies, the truncus arteriosus never splits. The wall separating the two lower heart chambers isn't closed completely. This results in a large hole between those chambers, called a ventricular septal defect.

Babies with truncus arteriosus also typically have a problem with the heart valve that controls blood flow from the lower heart chambers to the single vessel. This valve may not close completely when the heart relaxes. Blood can move the wrong way, back into the heart. This is called truncal valve regurgitation.

Risk factors

The exact cause of truncus arteriosus is unknown. But some things might increase the risk of a heart problem at birth. Risk factors include:


Truncus arteriosus causes severe problems with how blood flows through the lungs, heart and rest of the body.

Complications of truncus arteriosus in babies include:

Even with successful surgical repair of the heart during infancy, other complications can occur later in life. These complications include:

Common symptoms of these complications include:

Truncus arteriosus in adults

Rarely, some people born with truncus arteriosus can survive without surgery to fix the heart problems. They may live into adulthood. But those with the condition will almost certainly have heart failure and develop a complication called Eisenmenger syndrome. This syndrome is caused by permanent lung vessel damage. It results in a significant lack of blood flow to the lungs.


Because the cause is unclear, it may not be possible to prevent truncus arteriosus. Getting good prenatal care is important. If you have a family history of heart problems present at birth, consider talking with a genetic counselor and a heart doctor, called a cardiologist, before getting pregnant.

If you decide to get pregnant, taking these steps can help keep your baby healthy:


Truncus arteriosus is usually diagnosed soon after a child is born. The baby may look blue or gray and have trouble breathing.

When a baby is born, a health care provider always listens to the baby's lungs to check breathing. If a baby has truncus arteriosus, the provider may hear sounds of fluid in the lungs during this exam. The provider also listens to the baby's heart to check for irregular heartbeats or a whooshing sound, called a murmur.


Tests to diagnose truncus arteriosus include:


Infants with truncus arteriosus need surgery to improve blood flow and oxygen levels. Many procedures or surgeries might be needed, especially as a child grows. Medicines might be given before surgery to help improve heart health.

Children and adults with surgically repaired truncus arteriosus need regular health checkups for life.


Some of the medicines that might be given before truncus arteriosus surgery include:

Surgery or other procedures

Most infants with truncus arteriosus have surgery within the first few weeks after birth. The specific type of surgery depends on the baby's condition. Usually, the baby's surgeon:

The tube used to create the new pulmonary artery doesn't grow with a child. Follow-up surgeries are needed to replace the tube as the child grows.

Future surgeries may be done with a flexible tube called a catheter. This avoids the need for open-heart surgery. The health care provider inserts the catheter into a blood vessel in the groin and guides it to the heart. A new valve can be delivered through the catheter to the proper area.

Sometimes a small balloon at the tip of the catheter is inflated at the site of a blockage, widening a blocked artery. This procedure is called balloon angioplasty.

After truncus arteriosus surgery, a person needs lifelong follow-up care with a heart doctor specializing in congenital disease. This type of provider is called a congenital cardiologist.

Lifestyle and home remedies

If you or your child had truncus arteriosus, your provider may recommend taking a few steps to protect the heart.

Coping and support

Caring for a baby with a serious heart problem, such as truncus arteriosus, can be challenging. Here are some strategies that might be helpful.

Preparing for an appointment

What you can do

If possible, ask your family members about their medical history. Heart problems at birth can be passed down through families. So it's helpful to know if anyone in your child's family has a history of early heart problems.

Also make a list of questions to ask your baby's health care provider. Preparing this list can help you and your health care provider make the most of your time together. Here are some questions you might want to ask:

Don't hesitate to ask other questions.

What to expect from your doctor

Your child's health care provider typically asks the following questions:

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