Pulmonary Stenosis

What is pulmonary stenosis?

Anatomy of the heart, view of the valves

Pulmonary stenosis is a congenital (present at birth) defect that occurs due to abnormal development of the fetal heart during the first eight weeks of pregnancy.

The pulmonary valve is found between the right ventricle and the pulmonary artery. It has three leaflets that function like a one-way door, allowing blood to flow forward into the pulmonary artery, but not backward into the right ventricle.

With pulmonary stenosis, problems with the pulmonary valve make it harder for the leaflets to open and permit blood to flow forward from the right ventricle to the lungs in a normal fashion. In children, these problems can include:

  • A valve that has leaflets that are partially fused together.

  • A valve that has thick leaflets that do not open all the way.

  • The area above or below the pulmonary valve is narrowed.

There are four different types of pulmonary stenosis:

  • Valvar pulmonary stenosis.The valve leaflets are thickened and/or narrowed 

  • Supravalvar pulmonary stenosis. The pulmonary artery just above the pulmonary valve is narrowed

  • Subvalvar (infundibular) pulmonary stenosis. The muscle under the valve area is thickened, narrowing the outflow tract from the right ventricle

  • Branch peripheral pulmonic stenosis. The right or left pulmonary artery is narrowed, or both may be narrowed

Pulmonary stenosis may be present in varying degrees, classified according to how much obstruction to blood flow is present. A child with severe pulmonary stenosis could be quite ill, with major symptoms noted early in life. A child with mild pulmonary stenosis may have few or no symptoms, or perhaps none until later in adulthood. A moderate or severe degree of obstruction can become worse with time.

Illustration of pulmonary stenosis

Pulmonary stenosis is a component of half of all complex congenital heart defects.

Pulmonary stenosis accounts for 5 to 10 percent of all congenital heart defect cases.

Prevention & Risk Treatment

Prevention & Risk Treatment

What causes pulmonary stenosis?

Congenital pulmonary stenosis occurs due to improper development of the pulmonary valve in the first eight weeks of fetal growth. It can be caused by a number of factors, though most of the time this heart defect occurs sporadically (by chance), with no clear reason evident for its development.

Some congenital heart defects may have a genetic link, either occurring due to a defect in a gene, a chromosome abnormality, or environmental exposure, causing heart problems to occur more often in certain families.

Why is pulmonary stenosis a concern?

Mild pulmonary stenosis may not cause any symptoms. Problems can occur when pulmonary stenosis is moderate to severe, including the following:

  • The right ventricle has to work harder to try to move blood through the tight pulmonary valve. Eventually, the right ventricle is no longer able to handle the extra workload, and it fails to pump forward efficiently. Pressure builds up in the right atrium, and then in the veins bringing blood back to the right side of the heart. Fluid retention and swelling may occur.

What are the symptoms of pulmonary stenosis?

The following are the most common symptoms of pulmonary stenosis. However, each child may experience symptoms differently. Symptoms may include:

  • Heavy or rapid breathing
  • Shortness of breath
  • Fatigue
  • Rapid heart rate
  • Swelling in the feet, ankles, face, eyelids, and/or abdomen

The symptoms of pulmonary stenosis may resemble other medical conditions or heart problems. Always consult your child's doctor for a diagnosis.

Diagnosis

Diagnosis

How is pulmonary stenosis diagnosed?

Your child's doctor may have heard a heart murmur during a physical examination, and referred your child to a pediatric cardiologist for a diagnosis. In this case, a heart murmur is simply a noise caused by the turbulence of blood flowing through the narrowed pulmonary valve. Symptoms your child exhibits will also help with the diagnosis.

A pediatric cardiologist specializes in the diagnosis and medical management of congenital heart defects, as well as heart problems that may develop later in childhood. The cardiologist will perform a physical examination, listening to the heart and lungs, and make other observations that help in the diagnosis. The location within the chest that the murmur is heard best, as well as the loudness and quality of the murmur (harsh or blowing) will give the cardiologist an initial idea of which heart problem your child may have. Diagnostic testing for congenital heart disease varies by the child's age, clinical condition, and institutional preferences. Some tests that may be recommended include the following:

  • Chest X-ray. A diagnostic test that uses X-ray beams to produce images of internal tissues, bones, and organs onto film.
  • Electrocardiogram (ECG or EKG). A test that records the electrical activity of the heart, shows abnormal rhythms (arrhythmias), and detects heart muscle stress.
  • Echocardiogram (echo). A procedure that evaluates the structure and function of the heart by using sound waves recorded on an electronic sensor that produce a moving picture of the heart and heart valves.
  • Cardiac catheterization. A cardiac catheterization is an invasive procedure that gives very detailed information about the structures inside the heart. Under sedation, a small, thin, flexible tube (catheter) is inserted into a blood vessel in the groin, and guided to the inside of the heart. Blood pressure and oxygen measurements are taken in the four chambers of the heart, as well as the pulmonary artery and aorta. Contrast dye is also injected to more clearly visualize the structures inside the heart.
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