The Causes of a Common Arterial Trunk

Common arterial trunk appears during fetal development when the baby's heart is still forming. Therefore, this condition is already present at the time they're born.
The Causes of a Common Arterial Trunk

Last update: 27 November, 2020

Common arterial trunk, or arterial truncus, is a congenital malformation. In it, a single artery comes from the heart and it doesn’t have well-formed ventricles and atria.  In other words, a person has one large artery instead of two separate ones to carry blood in the lungs and the rest of the body.

This is a rare cardiac disease. Overall, there’s an incidence of 0.21-0.34% of people born with this congenital heart anomaly.

Causes of a Common Arterial Trunk

The arterial trunk inside a person.

In a normal heart, blood follows this cycle: body-heart-lungs-heart-body. When a person has a common arterial trunk, the blood that leaves the heart doesn’t follow the normal cycle.

In these cases, the heart doesn’t have four separate compartments. Instead, there’s only one cavity. So, there are neither atria nor ventricles that separate the blood (depending on its origin and destination, that is).

Therefore, there’s only one common artery. Also, there’s no specific route for blood rich in carbon dioxide, nor one with oxygenated blood.

A heart typically has two separate pathways: one for oxygenated blood and another for carbon-dioxide-rich blood.

A common arterial trunk appears during fetal growth when the baby’s heart is developing. Thus, this condition is present at the time of birth, so it’s a congenital problem.

The cause of this heart problem is still unknown in most cases. However, we do know several factors that may increase the risk of a common arterial trunk, including:

  • A family history of congenital heart problems.
  • Also, children with chromosome anomalies are at higher risk of developing this condition. This is especially true for those with velocardiofacial syndrome and DiGeorge syndrome.
  • Certain medications taken during pregnancy can harm a fetus.
  • Women who get viral diseases such as rubella may be more likely to give birth to a baby with a common artery trunk.

What are the Symptoms?

Each patient may experience symptoms differently. However, there are some common symptoms shared between babies afflicted by this condition.

The most common signs are:

  • Cyanosis
  • Fatigue
  • Sweating
  • Cold skin
  • Difficult, accelerated breathing
  • Accelerated heart rate
  • Respiratory congestion
  • Lack of appetite

However, all these symptoms may be common to other medical conditions or other heart problems. Thus, it’s very important to consult the doctor if your child presents any of these symptoms.

How Is it Diagnosed?

Various views of an echocardiogram.
Echocardiograms are one of the most effective techniques to diagnose congenital heart problems.

Doctors can usually diagnose this kind of anomaly before a baby is born. To do so, they use a fetal echocardiogram. This is a technique that uses sound waves to recreate a moving heart image.

Thanks to this, we can see the appearance of the heart and examine its functioning when a baby’s still in the womb. With this information, doctors can program treatment immediately after birth.

There’s also a pulse oximetry test. This is a simple test that measures the amount of oxygen present in the bloodstream. This is often the first clue that there is a heart problem.

Treatment for a Common Arterial Trunk

Unfortunately, data of common arterial trunk studies suggest 50% mortality during the first month of life alone. After this, survival in the first year of life is between 10-25%.

However, the vast majority of patients who survive past the first year of life. Nevertheless, many of them also have severe pulmonary vascular disease, which is often irreversible.

As for treatment, babies with this condition will need open heart surgery to prevent possible complications. This procedure is usually carried out during their first month of after birth. During surgery, the doctor separates the aorta and pulmonary arteries. This is to create a way for blood to go from the right ventricle of the heart into the lungs. They’ll also correct the interventricular communication and any other detected cardiac abnormality as well.

If surgery doesn’t correct this problem, the baby may die. However, surgery is usually successful.