Truncus Arteriosus (TA)
Overview
Truncus arteriosus is a heart defect that is present at birth (congenital). It happens
when there is an abnormal connection between the aorta and pulmonary artery. Normally,
the aorta and the pulmonary artery are separate. In truncus arteriosus, both the aorta
and pulmonary artery begin from a common blood vessel.
Another congenital heart defect that nearly always happens with this condition is
a
ventricular septal defect (VSD). This is an abnormal hole in the wall (septum) between
the two lower chambers of the heart (right and left ventricles).
In
truncus arteriosus, oxygen-poor (blue) and oxygen-rich (red) blood mix through the
VSD.
The mixed blood that goes to the body does not have as much oxygen as it should.
Causes
Some congenital heart defects may
occur more often in certain families. These are called genetic defects. Truncus
arteriosus is often seen in babies born with 22q11.2 deletion syndrome. But in most
cases, the cause is not known.
Symptoms
Symptoms of truncus arteriosus include:
- Blue
color to skin, lips, and nails (cyanosis)
- Problems
breathing
- Poor
feeding or eating
- Tiredness (fatigue)
- Enlarged liver
- Extreme
sleepiness
The
symptoms of truncus arteriosus can be like other health conditions. Have your child
see
their healthcare provider for a diagnosis.
Diagnosis
A
prenatal ultrasound may show truncus arteriosus. Your child's healthcare provider
will
check your child after birth. They may find signs like a pounding heart and weak pulse.
They may hear an abnormal heart sound (heart murmur) when listening to your baby's
chest
with a stethoscope. If they do, you may have been referred to a pediatric cardiologist
for a diagnosis. This is a healthcare provider with special training to diagnose and
treat heart problems in babies and children.
These
specialists will also examine your baby. They will listen to their heart and lungs
with
a stethoscope. Your baby may have other tests, including:
-
Pulse
oximetry.
A probe placed on your child's finger or toe can measure the oxygen
level. Low levels may mean a diagnosis of truncus arteriosus.
-
Chest
X-ray.
This shows the overall size and shape of the heart and lungs. It may
show signs typical of truncus arteriosus.
-
Electrocardiogram (ECG). An ECG records the electrical activity of the
heart. It shows abnormal rhythms, and finds heart muscle stress.
-
Echocardiogram (echo). An echo uses sound waves (ultrasound) to make a
moving picture of the heart and heart valves. An echo shows the truncus
arteriosus.
-
Cardiac
catheterization.
This gives very detailed information about the structures
inside the heart. Your baby will be given medicine to relax (sedation). The
healthcare provider will put a thin, flexible tube (catheter) into a blood vessel
in
the groin. It is then moved to the heart. They will take measurements of blood
pressure and oxygen in the heart chambers. The pulmonary artery and aorta will also
be checked. Contrast dye is also injected to let the provider more clearly see the
structures inside the heart.
Treatment
Treatment will depend on your child’s symptoms, age, and general health. It will also
depend on how severe the condition is.
Truncus arteriosus must be treated with surgery to fix the defects. Typically surgery
needs to occur during the first few days or weeks of life. But your child may need
medical support until it is time for the operation to take place. Support may
include:
- Medicines to help the heart pump better.
- A
device (noninvasive positive pressure ventilation) to help make breathing easier.
Some children may need mechanical ventilation.
Nutritional support may include:
-
Special nutritional supplements. These may be added
to formula or pumped breastmilk to increase calories.
-
Tube feedings. These are given through a small,
flexible tube that passes through the nose, down the esophagus, and into the
stomach. These feedings may be added to or take the place of bottle-feedings. Infants
who can drink part of their bottles, but not all, may be fed the rest through the
feeding tube. Infants who are too tired to bottle-feed may get their formula or
breastmilk through the feeding tube alone.
Surgery is often done in the first few weeks after birth to prevent lung damage. The
pulmonary arteries are separated from the aorta and reattached to the right ventricle.
The pulmonary arteries may be reattached directly to the right ventricle typically
using
a conduit. The ventricular septal defect is also closed. Your child will stay in the
hospital until after the surgical repair.
Complications
If
not treated, truncus arteriosus may cause complications, such as:
- Lung
damage
- Heart
failure
- Infection of the lining of the heart and heart valves (bacterial endocarditis)
- Poor
growth and development
- Diminished ability to function
- Easily
tired
- Death
Living with
Soon
after surgery, babies have more energy and start to eat better and gain weight faster.
But your baby may need high-calorie formula for several weeks or months after surgery.
Your baby may also need tube feedings until they are able to feed better.
Your
baby may become tired easily, and sleep more right after surgery. But in a few weeks,
they should be fully recovered.
You
may get other instructions from your child's cardiac team and the hospital staff.
Most
children who have had truncus arteriosus surgical repair will live healthy lives.
Their
activity levels, appetite, and growth will often return to normal. Talk with your
child's cardiologist about what activities and sports are safe for your child.
Your
child most likely will need more surgery and/or cardiac catheterization procedures
as
they grow. Surgery in young adulthood may also be needed. These surgeries may involve
replacing valves, repairing a narrowed aorta or pulmonary arteries, or replacing
conduits.
The
cardiologist may advise that your child take antibiotics before surgery or dental
procedures. This is to prevent infection in the lining of the heart and heart valves
(bacterial endocarditis).
Your
child will need regular follow-up care at a pediatric or adult congenital cardiac
care
center throughout life.
Talk
with the cardiologist about your child’s outlook.
When to Call a Healthcare Provider
Call your child's healthcare provider
if your child has trouble breathing or feeding, or develops new symptoms.
Key Points
- Truncus
arteriosus happens when there is an abnormal connection between the aorta and
pulmonary artery.
- It
causes oxygen-poor (blue) blood and oxygen-rich blood to mix and to be pumped to the
body. This causes blue skin, lips, or nails (cyanosis).
- The low
levels of oxygen may not be enough to meet the body's needs and sustain life.
- The
condition must be treated with surgery. Most children who have surgery will live
healthy lives.
- Your
child will need regular follow-up care with a pediatric cardiologist.
Next Steps
Tips
to help you get the most from a visit to your child’s healthcare provider:
- Know
the reason for the visit and what you want to happen.
- Before
your visit, write down questions you want answered.
- At the
visit, write down the name of a new diagnosis, and any new medicines, treatments,
or
tests. Also write down any new instructions your provider gives you for your
child.
- Know why
a new medicine or treatment is prescribed and how it will help your child. Also know
what the side effects are.
- Ask if
your child’s condition can be treated in other ways.
- Know why
a test or procedure is recommended and what the results could mean.
- Know
what to expect if your child does not take the medicine or have the test or
procedure.
- If your
child has a follow-up appointment, write down the date, time, and purpose for that
visit.
- Know
how you can contact your child’s healthcare provider after office hours. This is
important if your child becomes ill and you have questions or need advice.