Congenital Heart Defects: 6 Facts To Know About Truncus Arteriosus

Truncus arteriosus is a rare congenital heart disease in which, instead of two different blood vessels that take blood away from the heart (one to the lungs and one to the body), there is just one large blood vessel. Patients typically also have a hole between the two bottom chambers of the heart called a ventricular septal defect. This caused oxygen-rich blood and oxygen-poor blood to mix, leading to severe circulatory problems. Since there only one blood vessel leaves the heart, there is no particular pathway to the lungs for the blood.

What are the symptoms associated with truncus arteriosus?

Usually, children with truncus arteriosus will present with symptoms within the first few days of their life. Symptoms will often include:

• Cyanosis, a condition in which the baby has a lack of oxygen and acquires a bluish tint.
• Not feeding properly.
• Having a pounding heart.
• Being excessively sleepy.
• Growing very poorly.
• Having dyspnea, which refers to shortness of breath.
• Having tachypnea, which refers to rapid breathing.

You should seek medical treatment if your baby has cyanosis, is not feeding properly, and is excessively sleepy. You should be particularly diligent and take your child to the emergency department if you see your child has rapid or shallow breathing, a blue tint to the skin, and if your child loses consciousness.

What causes truncus arteriosus?

While the cause of truncus arteriosus is not yet known, it does occur when the baby is still a fetus when the heart is under development. Hence, truncus arteriosus is present at birth.

What are the risk factors for truncus arteriosus?

Despite the fact that the exact reason why truncus arteriosus develops is not known, there are several different factors that can lead to an increased risk of the disease. These risk factors include:

• If the mother has a viral illness, such as rubella or other virus, during pregnancy, particularly during early pregnancy, there is a higher risk that the baby will have congenital heart defects.
• If the mother has poorly controlled diabetes when she is pregnant, that also leads to a higher risk of the baby having heart defects.
• If the mother has taken certain medications when is pregnant, that can lead to a higher risk of congenital heart disease. You need to make sure that whatever medicine you take during pregnancy is safe. Talk to your doctor.
• There are certain chromosomal disorders (in which patients have an extra or impaired chromosome), such as with DiGeorge's syndrome or velocardiofacial syndrome, that are associated with a higher risk of developing truncus arteriosus.
• If the mother smokes when she is pregnant, she is more likely to have a baby who is born with a heart defect.

How is truncus arteriosus diagnosed?

After the baby has been born, the doctor might suspect a congenital heart disease if they hear an irregular heartbeat or heart murmur. At that point, the doctor may choose to order:

• An echocardiogram, which shows a detailed image of a heart using ultrasound waves.
• Chest X-rays, to create an image of the structures within the chest.

How is truncus arteriosus treated?

Treatment for truncus arteriosus involves using surgery to close the ventricular septal defect, as well as to separate the blood flow so that the blood can go to the body and to the lungs. Children with truncus arteriosus will need to undergo this surgery very early on in childhood, usually during infancy, to avoid the resulting high blood pressure from damaging the lungs permanently. Surgeons will use a patch to close the ventricular septal defect. They will also conduct a Rastelli repair, in which an artery is disconnected from the single blood vessel and a tube is put in so that the child will have two exiting blood vessels.

Truncus arteriosus needs to be treated and if it is not, the condition can be fatal. Usually, surgery for truncus arteriosus is successful, particularly when the repair is done before the baby is one month old.

What complications are associated with truncus arteriosus?

Truncus arteriosus is a serious disorder that can lead to significant problems with blood circulation. Since oxygen-rich and oxygen-poor blood become mixed, the body cannot get enough oxygen, leading to several complications including:

• Issues with breathing, as there is often too much blood flowing into the lungs and the extra fluid makes breathing difficult.
• Problems with pulmonary hypertension (high blood pressure), as there is such high blood volume in the lungs. This makes it very difficult for the baby’s heart to pump blood to the lungs.
• Cardiomegaly, which refers to an enlargement of the heart. Since circulatory and pulmonary issues cause the heart to work harder, the muscles can become large. Eventually, the larger heart gets weaker.
• Some children might experience heart failure (when the heart can’t pump an adequate amount of blood), which develops due to the higher workload and poor oxygen supply.