What is truncus arteriosus?
Sometimes a baby's heart doesn't grow properly in the womb. This can
cause a rare defect called a truncus arteriosus.
Normally, when the heart contracts, the right side takes blood from the
body and sends it to the lungs for fresh oxygen. This oxygenated blood then
travels to the left side of the heart, which pumps it to the rest of the body.
The main pulmonary artery is the vessel that carries blood from the
heart to the lungs. The one that sends it to the body is the aorta. A valve in
each artery regulates the flow to make sure the blood follows its usual path.
With the truncus arteriosus, these vessels do not become separate
canals. The child has only one large artery that carries blood to the lungs and
body.
A baby born with this condition usually has only one valve instead of
two that controls the outflow of blood from the heart, and this valve is often
problematic. It may be too thick or too narrow, which means that too little
blood can get into the lungs. Or it may leak, which means that the blood
returns to the heart.
In most cases, there is also a hole in the wall that separates the lower
chambers of the heart from each other. This means that oxygen-rich blood and
oxygen-poor blood can mix.
Causes and risk factors
As with most birth defects, doctors don't know what causes trunk
arteries. But some things can increase the chances of having a baby with heart
problems. These include things related to the mother, such as:
- They have an illness during pregnancy, such as rubella or diabetes, that's not managed properly.
- They smoke during pregnancy.
- They have a family history of heart defects or genetic disorders.
- They take medications that aren't recommended during pregnancy.
Symptoms and diagnosis
A baby with this birth defect has less oxygen in the blood than usual.
This can cause the skin around the mouth or nails to turn slightly blue. Their
breathing is often rapid and they may wheeze. Their pulse quickens and they
don't eat well.
These are signs that the baby isn't getting enough oxygen or is
developing congestive heart failure, which means the heart can't pump enough
blood to meet the body's needs. It can enlarge and weaken their hearts.
If the doctor thinks your child may have a truncus arteriosus, a simple
test that measures the amount of oxygen in the child's blood can help confirm
this. An echocardiogram, which uses sound waves to image the baby's heart, can
also help find the problem.
If a problem with the baby's heart is detected by ultrasound before the
baby is born, a fetal echocardiogram may be done to show more information about
the structure of the heart. This can help doctors and nurses prepare for any
complications when they are born.
Treatment
To solve this problem, an operation on the baby's heart is performed
within the first two weeks after birth. Before the procedure, the baby may be
given medicine to strengthen the heart and help the body get rid of fluid.
The surgeon will turn one blood vessel into two by inserting a tube
called a conduit that contains an artificial heart valve. This will connect the
right side of the heart to the blood vessel going to the lungs.
The original single blood vessel then becomes the aorta and carries
oxygen-rich blood from the heart to the body. A tissue patch covers the opening
between the two sides of the heart.
After the operation, the child will spend several days in the hospital
and may need painkillers such as acetaminophen or ibuprofen. It will take them
several weeks to fully recover, during which time they will likely need more
rest than usual.
Outlook and follow-up
Surgery is successful in more than 90% of babies who have it. But a
child born with the condition will need repeat surgeries and regular check-ups
with a cardiologist for the rest of their lives.
As your child grows, he will most likely outgrow the duct and will need
to be replaced two or three times. Over time, the duct can become narrow or
blocked and need to be opened or cleared. Sometimes the valve leading to the
reconstructed aorta can leak and need to be replaced.
Some children born with truncus arteriosus are unable to participate in
strenuous physical activity or play sports. And they will need to take
antibiotics before future surgery or dental treatment to prevent an infection
known as endocarditis, which affects the lining of the heart.
Some people also experience problems later in life, such as leaky heart valves, an irregular heartbeat, or high blood pressure in the lungs. A person born with a truncus arteriosus will need regular checkups for the rest of their life to keep these things under control or other heart problems.