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Pulmonary atresia is a congenital heart defect in which the pulmonary valve is missing or does not open.
The pulmonary valve is the valve between the right pumping chamber, or ventricle, and the pulmonary artery, which brings blood out to the lungs. When the valve is missing or not opening, blood is not able to follow the normal path from the right ventricle to the lungs.
Pulmonary atresia can be seen with a ventricular septal defect (VSD), a hole in the wall between the two pumping chambers. In this case, the blood can exit the right ventricle by going across the VSD and out to the body through the aorta. However, there is no way to get blood to the lungs.
When pulmonary atresia is seen without a VSD, it is called pulmonary atresia with intact ventricular septum (IVS). In these patients, the blood cannot exit the right ventricle unless it goes back the way it came (across the tricuspid valve). For this reason, not much blood flows into the right ventricle, and it does not grow well before birth. When the right ventricle does not grow normally, it is called hypoplastic, meaning small.
In most cases, there is no known cause for pulmonary atresia. DiGeorge syndrome can be associated with pulmonary atresia. Pulmonary atresia can be seen in the recipient of twin-to-twin transfusion syndrome.
Diagnosing Pulmonary Atresia
Pulmonary Atresia is usually diagnosed by:
- Echocardiogram - an ultrasound of the heart.
- Fetal echocardiogram - an ultrasound of the heart before birth
- Others may not be detected until after birth
- Failing the newborn pulse oximetry screen. The diagnosis would be confirmed with an echocardiogram
If the diagnosis of pulmonary atresia is discovered before birth, then your baby’s delivery may be planned. He or she will go to the neonatal intensive care unit (NICU) after birth. An echocardiogram will be done and the baby’s breathing and oxygen level will be monitored.
The same things would happen if the diagnosis is made after birth.
The baby would be started on a medicine called prostaglandins, which are given through an IV. The prostaglandins keep the PDA open, so blood flow gets to the lungs. This medication is not a long-term solution, so before the baby goes home a surgery or other procedure will need to be done.
Surgery for Pulmonary Atresia
There are a few different procedures that are done for babies with pulmonary atresia.
Which procedure is done depends on what is wrong with the pulmonary valve – the possibilities are different if the valve is completely missing, or if it is there but just unable to open. It also depends on whether or not there is a VSD (hole) or an IVS (no hole). The size of the baby also affects what type of initial surgery is best.
Pulmonary Atresia with VSD
The most common form of pulmonary atresia is seen with a VSD.
Many of these babies will require an initial surgery to supply blood flow to the lungs, followed by a later surgery to close the hole and provide a more long-term solution to get blood flow to the lungs.
The initial surgery for these babies is the placement of a shunt. A shunt is a small tube that would connect the aorta to the pulmonary artery, allowing blood to get to the lungs from the aorta. This acts just like the PDA, but does not require the IV medication.
After the shunt is placed, the oxygen level will still be decreased as the red and blue blood are still mixing before being pumped out of the heart.
At around 3-6 months the baby should be big enough for the next surgery.
The surgery at this stage can be done in two different ways depending on how big the pulmonary artery is and how it is attached to the heart.
- Transannular patch: The surgeon cuts across the abnormal pulmonary valve, removes the abnormal valve and places a patch to create an open connection between the right ventricle and pulmonary artery.
- Rastelli procedure: The surgeon places a prosthetic tube with a valve, called a homograft, between the right ventricle and pulmonary artery.
With both procedures, a patch is used to close the VSD. Sometimes, if the baby’s size and type of pulmonary atresia permits, the surgeon will do the transannular patch or Rastelli as the first step instead of the shunt.
There is no procedure that will make the heart normal. However, these surgeries fix all of the abnormal connections and should allow the blood flow to get to the lungs and body through the normal pathways.
Pulmonary Atresia with IVS
Pulmonary atresia with intact ventricular septum (IVS) may be addressed in different ways.
The decision about which procedure is needed depends mostly on the size of the structures on the right side of the heart.
- If the right side of the heart did not develop enough and is too small, then the baby will be treated as a “single ventricle” heart defect. This would require a shunt, as described above, and further surgeries to deal with the fact that there is only one pumping chamber.
- If the right heart structures are large enough, then the connection between the right ventricle and pulmonary artery needs to be restored. This can be done with a transannular patch or homograft (see above), or by a cardiac catheterization procedure. This would involve catheters which are placed in the blood vessels and the heart. These catheters can be used open up the abnormal valve and allow blood flow to get from the right ventricle to the pulmonary artery.
Follow-up After Surgery
Babies who have to undergo a shunt procedure will have to return later for the next part of the repair.
The procedures are all effective at fixing the abnormal connections in the heart (opening up the valve and closing the VSD). However, the heart can never be made 100% normal. Patients with pulmonary atresia need lifelong follow-up with a cardiologist.
Patients who have a transannular patch have no valve between the right ventricle and pulmonary artery. The blood can easily get out of the right ventricle, but it can also leak back into the right ventricle. Many of these patients will eventually need a valve replacement.
Patients who undergo the Rastelli procedure have a homograft with a valve that connects the right ventricle to the pulmonary artery. Since these are not made of the patient’s own body tissue, it does not grow and will need to be replaced every five to 10 years.
Any patient with pulmonary atresia may need future cardiac catheterizations or surgeries.
In general, the long term prognosis for pulmonary atresia is good.
Although patients may need additional surgeries or procedures, they are not typically on a lot of medications. Their activities are typically not limited. Some patients may develop heart rhythm abnormalities later in life, requiring medications or pacemakers.
When one family member has a congenital heart defect, there is an increased risk in other family members. A genetic counselor can better determine what the risk would be for future pregnancies.
To make an appointment with a Children's Heart Program physician, please call 410-328-4348.