Truncus Arteriosus

Truncus arteriosus is a heart defect in which a single artery instead of two (truncus arteriosus) carries blood from the heart. It’s a congenital condition, meaning a baby is born with it. A baby with truncus arteriosus also is born without a pulmonary valve.

In a normal heart, the aorta carries blood out of the left heart ventricle, and the pulmonary artery carries blood out of the right ventricle. With truncus arteriosus, there is only one blood vessel to pump blood to both the body and the lungs. Having just a single vessel means that oxygen-rich (red) blood and oxygen-poor (blue) blood is mixed and flows through the lungs and body. Over time, this can cause damage to the heart and lungs.

Children with truncus arteriosus also have a ventricular septal defect (VSD), a hole in the wall that normally separates the left and right ventricles.

Truncus arteriosus is rare. Fewer than one out of every 10,000 babies is born with this condition. Babies born with truncus arteriosus need surgery to repair the defect.

The most common symptoms of truncus arteriosus include:

• Fatigue
• Sweating
• Pale or cool skin
• Rapid or heavy breathing
• Rapid heart rate
• Congested breathing
• Disinterest in feeding, or tiring while feeding
• Poor weight gain
• Cyanosis (blue color of the skin, lips, and nail beds)

The heart forms during the first eight weeks of fetal development. The problem occurs at the midpoint of this time, when the aorta and the pulmonary artery don’t divide to form two separate vessels, but rather remain as a single vessel. It isn’t entirely clear what causes congenital heart malformations, including truncus arteriosus, although in most cases it appears that some combination of genetics and environmental factors is involved.

Truncus arteriosus and some other cyanotic congenital heart defects are sometimes associated with chromosomal disorders.

Truncus arteriosus is usually diagnosed before birth or soon after a baby’s birth. In some cases, truncus arteriosus is diagnosed during pregnancy with an echocardiogram of the of the baby’s heart.

If your newborn baby is born with a bluish tint to the skin, or if your young child has symptoms of a heart problem, your pediatrician will refer you to a pediatric cardiologist for an exam and testing.

Your child’s doctor may order one or more of the following tests to confirm a diagnosis of truncus arteriosus, and to provide detailed information on the shape and condition of your baby’s heart:

• Echocardiogram (cardiac ultrasound)
• Chest X-ray
• Electrocardiogram (ECG or EKG)

Truncus arteriosus must be treated through surgery. While your baby is waiting for surgery, he or she may need to take medications to reduce fluid in the lungs and have high-calorie feedings to build strength.

Most babies with truncus arteriosus need surgery in the first few days or weeks of life. During the surgery, the surgeon will:

• Detach the pulmonary arteries from the common artery (truncus arteriosus)
• Connect the pulmonary arteries to the right ventricle using a homograft (a section of pulmonary artery and its valves from a tissue donor) or an artificial conduit (a small tube containing a valve)
• Close the ventricular septal defect (VSD) with a patch.

During the operation, a heart-lung machine does the work of the baby's heart and lungs. The machine protects the heart muscle, brain, and other organs.

Most children who've had surgery for truncus arteriosus recover and grow normally. However, your child will need regular check-ups with a cardiologist, since this condition puts them at risk for arrhythmias, leaky valves, and narrowing of the lung arteries. Your child may also need additional procedures as he or she grows, since children eventually outgrow the homograft or conduit repair.

Your child's cardiologist will help you create a long-term care program as your baby matures into childhood, the teen years, and adulthood, where we continue care in the Boston Adult Congenital Heart (BACH) and Pulmonary Hypertension Program. Most people who have had congenital heart disease repair will have an ongoing relationship with their cardiologist.

Our team in the Boston Children’s Hospital Benderson Family Heart Center treat some of the most complex pediatric heart conditions in the world, with overall success rates approaching 98 percent — among the highest in the nation among large pediatric cardiac centers. Our specialized training in pediatric cardiology means we understand the unique challenges, circumstances, and intricacies of working with young people who have heart conditions. In addition to our medical expertise, we provide patient-centered care that always recognizes your child as an individual — and we offer resources to meet the needs of your entire family.

Care for truncus lasts a lifetime. We specialize in the neonatal full repair but also specialize in the follow-up care which can include:

• Pulmonary valve replacements, either with a catheter or surgically
• Heart catheterization to help the pulmonary arteries grow

Sometimes, the truncal valve can leak and it needs to be repaired or replaced at some point in the future.

Pediatric cardiologists and pediatric cardiovascular surgeons at Boston Children’s Hospital have pioneered the interventional catheterization techniques now used widely for many congenital heart defects.

A significant amount of the groundbreaking cardiac research currently being conducted at Boston Children’s aims to refine and advance the open-heart surgery and catheterization procedures that correct congenital heart defects in newborns and young children — including truncus arteriosus.

We also specialize in complex neonatal truncal valve repairs. Sometimes, patients have anomalous coronary arteries off of the aorta. We specialize and have great success with truncal valve repairs. We even have a lot of experience with truncus-arteriosus and aortic-arch anomalies.