Truncus Arteriosus

Truncus arteriosus is a congenital heart defect in which the heart has one main artery (truncus) connected to both pumping chambers of the heart instead of two separate arteries.

About Truncus Arteriosus

In a normal heart, the pulmonary artery connects to the right ventricle (pumping chamber of the heart) to allow blood to flow to the lungs and the aorta connects to the left ventricle to allow blow to flow to the rest of the body. Truncus arteriosus occurs when the heart only has one main artery (truncus) connected to both pumping chambers of the heart instead of two separate arteries. This single truncus supplies blood flow to both the lungs and the body.

When patients are diagnosed with truncus arteriosus, they almost always have a hole between the two pumping chambers of their heart (ventricular septal defect), which allows the mixing of oxygen-rich and oxygen-poor blood and causes the blood to not be as oxygenated as it should be.

Symptoms of Truncus Arteriosus

Symptoms of truncus arteriosus usually appear within the first days of life.

Symptoms of truncus arteriosus may include:

• Difficulty feeding or sweating during feeding
• Lips, skin, or nails that are blueish in color
• More sleepiness than normal
• Poor weight gain
• Rapid breathing

Diagnosing Truncus Arteriosus

Truncus arteriosus is often diagnosed during prenatal ultrasounds before a baby is born. During physical examinations, your child’s doctor listens to your child’s heart and lungs and may detect a heart murmur, which are extra sounds heard throughout the cardiac cycle due to increased blood flow. If your pediatrician suspects increased blood flow, a recommendation to see a pediatric cardiologist may be made. Your doctor may also refer you to a pediatric cardiologist if your child is breathing fast or has lips or skin that appear blue in color. Once the diagnosis of truncus arteriosus has been made, chromosomal analysis should be performed to determine if the baby also has a genetic condition or syndrome.

Tests performed when diagnosing truncus arteriosus may include:

• Cardiac Catheterization: During cardiac catheterization, a small catheter (thin tube) is inserted into a larger blood vessel, typically in the groin, and guided to the heart where blood pressure and oxygen measurements can be taken in the aorta and pulmonary artery as well as the four chambers of the heart. A dye can also be injected through the tube to make the heart’s structure more visible on an X-ray.
• Cardiac MRI or CT Scan: A cardiac MRI or CT scan is used to take more detailed images of the heart to help define the anatomy and detect anomalies.
• Chest X-Ray: A chest X-ray produces an image of the tissue and bones in the heart and lungs and helps your provider assess the shape, size, and structure of the heart and lungs as well as the aeration of or any congestion in the lungs.
• Echocardiogram: An echocardiogram uses ultrasound technology to create a moving image of the heart and its valves, allowing your provider to assess the structure and function of the heart. An echocardiogram also helps provide information about blood flow and how well the heart is pumping blood.
• Electrocardiogram (ECG or EKG): An electrocardiogram uses electrodes that are placed on the body to record the electrical activity taking place in the heart. An ECG/EKG test helps detect abnormal rhythms, such as cardiac arrhythmias, stress on the heart, and damage to the heart muscles.

Treating Truncus Arteriosus

Treatment of truncus arteriosus requires open-heart surgery, usually shortly after birth. During surgery, the pulmonary arteries will be separated from the trunk and connected to the pulmonary arteries to the right pumping chamber (ventricle) of the heart using tubes or conduits. The trunk is repaired so that it becomes a separate functioning aorta or main body artery. If the baby also has a ventricular septal defect, this is typically closed by placing a patch over the hole during the same operation.

Care Team Approach

The Texas Center for Pediatric and Congenital Heart Disease, a clinical partnership between Dell Children’s Medical Center and UT Health Austin, takes a multidisciplinary approach to your child’s care. This means your child and your family will benefit from the expertise of multiple specialists across a variety of disciplines. Your care team will include pediatric cardiologists, cardiothoracic surgeons, interventional cardiologists, critical care specialists, hospitalists, anesthesiologists, perfusionists, nurses, advanced practice providers, social workers, psychologists, child life specialists, dietitians, physical and occupational therapists, pharmacists, and more, who work together to provide unparalleled care for patients every step of the way. We collaborate with our colleagues at the Dell Medical School and The University of Texas at Austin to utilize the latest research, diagnostic, and treatment techniques, allowing us to identify new therapies to improve treatment outcomes. We are committed to communicating and coordinating your child’s care with referring physicians and other partners in the community to ensure that we are providing comprehensive, whole-person care.

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