Pulmonary atresia (uh-TREE-zhuh) is one of several heart valve defects that may be found at birth or soon after. In pulmonary atresia, the valve between the heart and lungs (pulmonary valve) is not fully developed, which prevents forward blood flow to the lungs, and your baby doesn't get needed oxygen.
Normally, some blood enters the lungs through other passages within the heart and its arteries. Before your baby is born, it receives blood through a hole (foramen ovale) between the top chambers of your baby's heart, and oxygen-rich blood is pumped out to the rest of your baby's body. After birth, the foramen ovale usually closes, but in pulmonary atresia it may stay open. Another temporary opening (ductus arteriosus) may allow some blood flow, but your baby will need medication, procedures or surgery to correct the atresia.
In this heart defect, there is also a hole between the two pumping chambers of your baby's heart (ventricular septal defect, or VSD). The pulmonary artery and its branches can be very small or nonexistent. In the latter case, additional arteries arise from the aorta to provide blood flow to the lung (major aortopulmonary collateral arteries, or MAPCAs).
Doctors may use several tests to diagnose pulmonary atresia:
- X-ray. An X-ray shows your baby's doctor the shape and size of your baby's heart and any defects.
- Echocardiogram. In an echocardiogram, sound wave movement reveals the features of your baby's heart. Your doctor might also use an echocardiogram of your abdomen before you deliver your baby (fetal echocardiogram) to diagnose pulmonary atresia.
- Electrocardiogram (ECG). In this test, sensor patches with wires attached (electrodes) measure the electrical impulses given off by your baby's heart. An ECG finds abnormal heart rhythms (arrhythmias or dysrhythmias) and may show other heart damage.
- Cardiac catheterization. In catheterization, the doctor inserts a thin, flexible tube (catheter) into a blood vessel in your baby's groin and guides it to your baby's heart. This test shows your baby's heart structure and the blood pressure and oxygen levels in your baby's heart, pulmonary artery and aorta. The doctor may inject a dye into the catheter to see your baby's arteries more easily under X-ray.
- Cardiac CT scan. This is a scan of your baby's heart and blood vessels to help understand the anatomy and the presence of these collateral arteries (MAPCAs), which will be important for planning the repair.
Medication and several procedures may be needed to treat your baby's pulmonary atresia with ventricular septal defect.
Procedures. Your baby will need one or more procedures to improve heart function and blood flow. There are several treatment pathways depending on the anatomy of the pulmonary arteries and the presence or absence of the MAPCAs.
- Stent placement. Placement of a rigid tube (stent) between the aorta and pulmonary artery (ductus arteriosus) allows blood to flow to your infant's lungs.
- Systemic-to-pulmonary artery shunt. In this procedure, your infant's surgeon uses a part of an artery from another part of the body to create a passage for blood flow (shunt).
- Neonatal complete repair. If your baby's heart has well-developed pulmonary arteries and no MAPCAs, your baby's surgeon can perform the complete repair in one stage during the neonatal period. This will include closure of the ventricular septal defect and placement of a valve conduit between the right ventricle and the pulmonary artery.
- One-stage complete repair. In this procedure, your baby's surgeon connects all the MAPCAs together to create the new pulmonary arteries and then completes the repair with closure of the VSD and placement of the conduit. This is usually performed between 4 and 6 months of age. This procedure may also be called unifocalization.
- Staged unifocalization. If the MAPCAs are small or have multiple areas of narrowing, they may be connected in stages. This allows the arteries to grow to adequate size prior to the complete repair. The source of blood flow to the lungs will be provided through a small shunt from the aorta to the newly constructed pulmonary arteries. After a few months, your baby's heart will be evaluated with a cardiac catheterization and cardiac CT scan to determine the suitability and timing of the complete repair.
- Catheter interventions for the pulmonary artery branches. This procedure is done to assess the anatomy of your baby's heart and reconstruct pulmonary artery branches and dilate or stent the areas that have narrowing in them.