Pediatric Pulmonary Stenosis

Pulmonary stenosis is a birth defect of the heart (congenital). It can happen when the pulmonary valve doesn’t grow as it should in a baby during the first 8 weeks of pregnancy. The pulmonary valve connects the right ventricle to the pulmonary artery. It normally has 3 flaps (leaflets) that work like a 1-way door. This means they allow blood to flow from the right ventricle to the pulmonary artery, but not backward from the pulmonary artery to the right ventricle.

With pulmonary stenosis, it is harder for the flaps to open and the blood to flow as it should. The flaps may be stuck together. Or the flaps may be thick and not able to open all the way. In some cases, the valve may be narrowed. In some cases, the stenosis may not be related to a problem with the valve leaflets but with the area directly below and above the valve.

Pulmonary stenosis varies according to how much of the blood flow is blocked. A child with severe pulmonary stenosis is likely to be quite ill and have clear symptoms. A child with mild pulmonary stenosis may have few or no symptoms. They may get symptoms later in life. The blockage and symptoms can get worse over time. It is uncommon for this condition to be found during pregnancy. 

Pulmonary stenosis often occurs as part of other complex congenital heart defects.

Pulmonary stenosis occurs when the pulmonary valve doesn’t grow as it should or the area below or above the valve doesn't grow fully in a baby during the first 8 weeks of pregnancy. Why this happens isn't known.

Some congenital heart defects are passed down through families (genetic defects).

If not treated, moderate to severe pulmonary stenosis can cause complications. The right ventricle has to work harder to try to move blood through the pulmonary valve or narrowed area. In time, the right ventricle becomes enlarged and is no longer able to handle the extra work. It fails to pump well (heart failure). Another complication can be an abnormal heart rhythm (arrhythmia).

Some children with pulmonary stenosis do not have symptoms. The more severe the stenosis, the more likely the child is to have symptoms. The most common symptoms may include:

• Hard or fast breathing
• Bluish color around the lips or fingers that mean low oxygen levels (cyanosis)
• Shortness of breath
• Feeling tired, especially with activity or exercise
• Fast heart rate
• Swelling of the legs, ankles, feet, face or belly (abdomen)
• Fainting
• Chest pain

The symptoms of pulmonary stenosis can be like other health conditions. Make sure your child sees a healthcare provider for a diagnosis.

The healthcare provider will ask about your child’s symptoms and health history. They will give your child a physical exam. The provider will listen to your child's heart and lungs with a stethoscope. The provider may hear an abnormal heart sound (heart murmur). They may also find other signs or symptoms. The provider may refer your child to a pediatric cardiologist. This is a doctor with special training to treat heart problems in children.

The cardiologist will also examine your child. They will carefully listen for a heart murmur. The details about the heart murmur will help with the diagnosis. Your child may have tests, such as:

• Echocardiogram (echo). An echo uses sound waves (ultrasound) to make a moving picture of the heart and heart valves. This test is most helpful in diagnosing pulmonary stenosis.
• Chest X-ray. A chest X-ray may show changes of the heart or pulmonary artery.
• Echocardiogram (ECG). An ECG records the electrical activity of the heart. It shows abnormal rhythms (arrhythmias), and finds heart muscle stress. Although the ECG is often normal, it may show abnormalities that are found with pulmonary stenosis.
• Cardiac catheterization. Your child is given medicine to help them relax. The healthcare provider puts a thin, flexible tube (catheter) into a blood vessel in the groin. They move it to the heart. The heart is checked by measuring blood pressure and oxygen in the 4 chambers of the heart. The pulmonary artery and aorta are also checked. Contrast dye is also injected to let the provider more clearly see the structures inside the heart. Your child may not need this test if the diagnosis can be made with an echocardiogram.

Mild pulmonary stenosis often does not need treatment. Moderate or severe stenosis needs repair.

Some infants will be very sick and need care in the intensive care unit (ICU) before the defect can be fixed. Some infants may need an emergency repair if the stenosis is very severe. Prostaglandins, a medicine that keeps the ductus arteriosus open, will be given so that enough blood flows in the lungs. Once the child is stabilized, a procedure will be done to repair the valve. A child with less severe stenosis will have the repair scheduled.

Repair choices include:

• Balloon dilation or valvuloplasty. A thin, flexible tube (catheter) is put into the heart. The catheter has a balloon on the tip. When the catheter reaches the narrowed valve or area, the provider inflates the balloon for a short time to stretch it open. Children who have had balloon dilation may need to take antibiotics to prevent heart infection after being discharged from the hospital.
• Valvotomy. This is surgery to remove scar tissue from the pulmonary valve leaflets. This lets the valve open as it should.
• Valvectomy. This is surgery to remove the valve. Often a patch is used to help the blood flow from the right ventricle into the pulmonary artery. The pulmonary valve may need to be replaced when the child is an adult.
• Patch enlargement. Patches are used to enlarge narrowed areas. They may be added to the right ventricle or the pulmonary artery.
• Pulmonary valve replacement. Some children may need to have the pulmonary valve replaced. A tissue valve (pig or human) may be used. Children who have had valve replacement will need to take antibiotics before medical and dental procedures in the future.

The outlook for children with pulmonary stenosis is usually excellent. For a period of time, your child's cardiologist may advise that your child take antibiotics to prevent infection of the heart lining and valves (bacterial endocarditis). Your child may need to take them before medical and dental procedures.

In some cases, a child may need to have procedures done again over time to stretch the valve open. Your child may need a pulmonary valve replacement as a teen or young adult to prevent complications.

Your child will need regular follow-up care at a congenital cardiac care center during their life. 

Check with your child's cardiologist about your child's outlook.

Your child's cardiologist may recommend that antibiotics be given to prevent bacterial endocarditis for a period of time following surgery and always for all valve replacements.

Occasionally, repeat interventional cath lab procedures may be necessary during infancy and childhood to stretch the valve open. Replacement of the pulmonary valve may be recommended later during adolescence or early adulthood to prevent complications such as enlargement of the right ventricle, heart failure and arrhythmias (irregular or fast heartbeats).

Regular follow-up care at a center offering pediatric or adult congenital cardiac care should continue throughout the individual's lifespan.

Consult your child's doctor regarding the specific outlook for your child.