Truncus Arteriosus

What is truncus arteriosus?

Truncus arteriosus (TRUN-kus are-teer-e-OH-sus) is a congenital heart defect (heart condition that’s present at birth). A baby with truncus arteriosus has one large artery (instead of the usual two arteries) for blood to flow in and out of the heart. These babies also have a single truncal valve instead of two valves to control this blood flow.

Truncus arteriosus is a life-threatening condition. It requires surgery shortly after birth.

How does truncus arteriosus affect blood flow?

The heart and the arteries are part of the body’s circulatory system. A healthy heart should have a pulmonary artery (sends blue blood to the lungs) and an aorta (sends red blood to the body). A pulmonary valve and an aortic valve are two of the four valves that control blood flow through the heart.

Typically, blood flows from the right side of the heart through the pulmonary artery to the lungs to get oxygen. This oxygenated blood then flows to the left side of the heart and through the aorta to the rest of the body. Because a baby with truncus arteriosus only has one artery leading out of the heart, blood with and without oxygen mixes together.

Babies with truncus arteriosus also have ventricular septal defects (VSD). A VSD is a hole in the heart wall (septum) that separates the lower ventricles, or chambers, of the heart.

These two congenital heart defects allow too much blood to go into the lungs while not enough blood reaches the rest of the body. This forces the heart and lungs to work harder.

How common is truncus arteriosus?

Truncus arteriosus is a rare birth defect (congenital disability). It occurs in approximately 1 in 10,000 births and affects baby boys and girls equally. Healthcare providers diagnose about 250 babies with this heart condition every year.

What other heart conditions occur with truncus arteriosus?

Other heart conditions associated with truncus arteriosus include:

• Atrial septal defect or ASD (hole in the heart wall separating the heart’s two upper chambers or atria).
• Interrupted aortic arch (incomplete aorta).
• Patent ductus arteriosus or PDA (abnormal connection between the aorta and pulmonary artery).

What causes truncus arteriosus?

In the uterus, all fetuses start with one large blood vessel (the truncus) that branches from the heart. As the fetus develops, the truncus divides into the pulmonary artery and aorta. When this split doesn’t happen, truncus arteriosus occurs. Not having the separation also leads to the VSD.

Experts are still trying to determine why some fetuses develop this type of congenital heart defect. It’s possible that certain gene changes play a role. About 1 in 3 children with truncus arteriosus also have a chromosomal disorder called DiGeorge syndrome. In addition to heart defects, this condition causes immune system problems and developmental delays.

What are the risk factors for truncus arteriosus?

A family history of congenital heart defects may increase the risk of a child having truncus arteriosus.

Certain factors that occur during pregnancy may also play a role. These include:

• Diabetes.
• Excessive alcohol use.
• Medication use.
• Rubella (German measles) or another virus.

What are the symptoms of truncus arteriosus?

Newborns with truncus arteriosus often show signs of distress soon after birth because the heart is working too hard to pump blood.

Signs of truncus arteriosus include:

• Bluish or grayish tint to skin (cyanosis).
• Breathing problems, such as shortness of breath or rapid breathing.
• Extreme sleepiness.
• Heart murmur.
• Poor feeding.
• Rapid heart rate or weak pulse.
• Sweating.

How is truncus arteriosus diagnosed?

A prenatal ultrasound that takes place during pregnancy sometimes detects this heart defect. If an ultrasound indicates a potential problem, you may get a fetal echocardiogram. This type of ultrasound produces images of the fetal heart.

After your baby is born, a healthcare provider may use an echocardiogram to diagnose truncus arteriosus.

What are the complications of truncus arteriosus?

Untreated truncus arteriosus can lead to:

• Arrhythmia (abnormal heart rhythm).
• Heart failure.
• Hypertrophy (enlarged heart).
• Pulmonary hypertension (high blood pressure in the lungs).
• Stroke.

How is truncus arteriosus managed or treated?

Babies with truncus arteriosus need heart surgery within the first weeks of life. There are several procedures to correct truncus arteriosus. The most common procedure is called a Rastelli repair. The surgery involves:

• Using a patch to close the VSD, or hole in the heart.
• Creating a new aorta using the existing single blood vessel (truncus).
• Placing an artificial tube (conduit) and artificial valve to create a new pulmonary artery and valve.

A newborn may also need:

• High-calorie formulas or feeding tubes to promote weight gain.
• Medications before surgery to strengthen the heart, get rid of excess fluid and manage blood pressure.

Will my child need other treatments?

Children with truncus arteriosus have a higher risk of developing a serious bacterial heart infection called endocarditis. Your child may need to take antibiotics before seeing the dentist or getting surgical procedures. Your child may need cardiac catheterizations (a procedure to look inside the heart) and repeat surgery to either address the truncal valve (new aortic valve) and/or the artificial tube used to make the new pulmonary artery.

Can you prevent truncus arteriosus?

Truncus arteriosus occurs for no known reason. There isn’t anything you can do to prevent it. For a healthy pregnancy, people should limit alcohol consumption (or not drink at all) and check with healthcare providers before taking medications.

What is the prognosis (outlook) for children who have truncus arteriosus?

After surgery, most children enjoy full, active lives. Your child may be able to play certain sports but should probably avoid high-impact activities. Talk to your healthcare provider about what activities are safe for your child.

Children with this heart condition need to see a heart specialist (pediatric cardiologist) for ongoing care. They will need to see a cardiologist throughout their life and will need to transition care to an adult congenital cardiologist around their 18th birthday. This doctor monitors your child’s heart health to quickly detect problems like leaky heart valves.

Will my child need additional surgeries for truncus arteriosus?

A child will need two to three surgeries to replace the artificial pulmonary artery with larger tubes as their heart and body grow. If the truncal valve thickens and becomes leaky, your child may get an artificial valve. Some people need another conduit and valve replacement procedure during adulthood.

Rarely, the artificial artery narrows or becomes blocked. Your child’s provider may perform a catheter-based procedure using a balloon device to open it up. Or the provider may place a stent (tiny tube) into the artery to keep it open.

When should I call the doctor?

You should call your healthcare provider if your child experiences:

• Bluish or ashen skin tone.
• Changes in heart rate or rhythm.
• Chest pain or breathing problems.
• Dizziness or fainting.
• Extreme fatigue.
• Lack of appetite or unexplained weight loss.

What questions should I ask my doctor?

You may want to ask your healthcare provider:

• What treatments can help my child?
• Are there any activities my child should avoid?
• When will my child need another surgery?
• Should I look out for signs of complications?

A note from Cleveland Clinic

Truncus arteriosus is a rare but serious congenital heart defect. It often occurs along with a ventricular septal defect or hole in the heart. These heart conditions allow blood with and without oxygen to mix. The heart must work harder to get oxygenated blood to the body. A baby with truncus arteriosus needs surgery soon after birth to correct the problem. Your child will need more heart surgeries as they grow. Most children with this heart defect live long, happy lives after surgical treatment.