Truncus arteriosus: symptoms and treatment

In a normal heart, two arteries leave the heart. The pulmonary artery carries oxygen-poor blood to the lungs, and the aorta carries oxygen-rich blood to the body. The Children’s Heart Federation explains that, in early pregnancy, one large vessel, the truncus arteriosus, should divide into those two arteries.

In truncus arteriosus it does not divide. The single vessel has one large valve instead of separate aortic and pulmonary valves, and sits over a hole between the pumping chambers. Blood from both sides of the heart therefore enters the single trunk. The BHF says oxygen-rich and oxygen-poor blood mix, the lungs and body get less oxygen than they should, and the heart works harder.

The charity says the result is usually too much blood going to the lungs and too little oxygen-rich blood reaching the body. The BHF uses the name common arterial trunk too.

The BHF says there are different types depending on where the blood vessels sit in the heart. The Children’s Heart Federation describes three main types by how the lung arteries branch from the trunk. MSD describes several classification systems used by cardiologists.

The BHF says most people have no symptoms other than a heart murmur. Babies may seem healthy at birth, then become more breathless over the first few weeks as blood flow to the lungs rises. MSD says infants usually show mild blueness and heart failure signs in the first few weeks of life.

• Blue skin or lips.

• Fast or laboured breathing and shortness of breath.

• Not feeding or eating well, and sweating while feeding.

• Feeling very tired.

• Irregular or extra heartbeats.

• Poor weight gain, which the Children’s Heart Federation links to heart failure from extra blood flow to the lungs.

The Children’s Heart Federation says truncus arteriosus can sometimes be seen on a scan in pregnancy. The NHS notes that the 20-week scan screens for congenital heart disease but cannot find everything. After birth a heart murmur or colour changes may prompt tests.

The BHF says most people are diagnosed shortly after birth or in childhood, and some adults are diagnosed through a health check or symptoms. The most common test is an echocardiogram. A chest X-ray and ECG may also be used, adults may need a cardiac MRI, and a heart catheter test can look at heart function in more detail. MSD also lists CT angiography.

Babies are checked for other conditions at the same time, including 22q11 deletion syndrome, which the BHF says can cause learning difficulties and more frequent illness because the body cannot fight infection as well.

The Children’s Heart Federation says surgery is needed before the raised pressure irreversibly damages the lungs. This is open heart surgery using a heart bypass machine. The BHF describes the repair: the VSD is closed first, then the large vessel is turned into the aorta, and a new pulmonary artery is built with an artificial tube called a conduit.

The charity explains that the conduit, or homograft, does not grow with the child, so further operations are needed as the child grows. It says this could be perhaps another two or three open heart surgeries. Operations at the same time may deal with other heart problems.

MSD says medical treatment for heart failure usually comes first, followed by early surgical repair. The doctors discuss risks in detail before asking for consent, and the Children’s Heart Federation says the risk depends on how severe the defect is and how well the child is otherwise.

After surgery, a child is cared for in a recovery area and then on a ward. The Children’s Heart Federation says most babies are well, active and gaining weight a few days after surgery, with a scar down the middle of the chest. Chest infections and wound infections are not uncommon, some children develop fast or slow pulse rates needing medicine, and some need aspirin or warfarin because blood flows slowly through the conduit.

The BHF says you will usually need more surgery in the future, such as heart valve repair or replacement, or conduit repair if it becomes too narrow. It advises going to every appointment even when you feel well, and talking to the team about exercise, pregnancy and endocarditis risk. People with congenital heart disease, including truncus arteriosus, have an increased risk of endocarditis, and antibiotics may be recommended before or after some procedures.

The NHS advises calling 999 if a child with congenital heart disease has lips, tongue, face or skin that suddenly turn blue or grey, has difficulty breathing, chest pain, is confused or drowsy, has heart rhythm problems, or is limp, floppy or not responding normally. Do not drive to A&E.

For a less urgent worry about a child under 5, the NHS says to call 111. The Children’s Heart Federation advises families to make sure the GP, health visitor and local emergency department have the details of the child’s condition from the heart team, and to keep the number of a cardiac liaison nurse.

Surgery for truncus arteriosus is carried out in specialist paediatric cardiac centres, within the NHS. The NHS says people with congenital heart disease are referred to a specialist team at an NHS hospital, with regular check-ups afterwards.

Private cardiology can provide second opinions and echocardiograms, and adult congenital heart services take over as children grow. For the repair itself, the key factor is access to a centre with experience in operating on newborns.