Truncus Arteriosus

What is truncus arteriosus?

Truncus arteriosus is a rare heart condition where there is just a single blood vessel coming from the ventricles of the heart instead of two.

Normally, the heart has two great vessels leaving the ventricles called the aorta and pulmonary artery. The aorta takes blood to the body and has an aortic valve and the pulmonary artery takes blood to the lungs and has a pulmonary valve. These valves control the flow of the blood. In truncus arteriosus there is just a single blood vessel coming from the ventricles of the heart instead of two.

There is usually a hole in the wall between the ventricles called a ventricular septal defect (VSD) and the vessel sits over this hole allowing blood from both ventricles to flow through. The vessels that go to the lungs (pulmonary arteries) arise from this single large vessel.

Also, instead of there being an aortic valve and a pulmonary valve, there is a single common valve called a truncal valve which controls the blood flow. Sometimes, this  valve can not function properly.  It can be thickened making it difficult for blood to leave the heart or it can be leaky allowing  blood that has already left the heart to leak back into the heart.

There are three different types of truncus arteriosus where the pulmonary arteries arise from the common trunk in one of several patterns.

How can truncus arteriosus be spotted?

Truncus arteriosus can be detected at the 20-week anatomy scan or after birth by echocardiogram.

If it is not picked up in the antenatal period, once the baby is born it will display the following signs:

• rapid breathing
• grunting or very noisy breathing
• nasal flaring
• poor feeding
• bluish skin colour

How can truncus arteriosus be treated?

Surgical repair is usually performed in the first few weeks of life and this will be open heart surgery under general anaesthetic.

This will involve the pulmonary arteries being separated from the single common artery and placement of a valve and an artificial tube (conduit) to create a connection between the pulmonary arteries and the right ventricle.

The hole between the ventricles will be closed and repair of the single trunk and truncal valve so that it becomes a fully functioning aorta.

Full recovery usually takes a few weeks.

General advice/info for the future

Babies and children with truncus arteriosus (even when surgically treated) will need lifelong follow-up.

Sometimes they can experience other heart problems later in life, including an irregular heartbeat or a leaky aortic valve.

Further surgeries in the future will be required to replace the conduit because this does not grow with the child.

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