Pulmonary valve stenosis is a narrowing of the valve between the lower right heart chamber and the lung arteries. In a narrowed heart valve, the valve flaps may become thick or stiff. This reduces blood flow through the valve.

In pulmonary stenosis, the pulmonary valve is narrowed. The greater the narrowing, the harder the lower right heart chamber, called the right ventricle, must work to pump blood to the lungs. The increased pressure causes the right ventricle to become thick.
Usually, pulmonary valve disease is caused by a heart problem that develops before birth. A heart problem present at birth is called a congenital heart defect. In adults, pulmonary valve stenosis may be a complication of another illness.
Pulmonary valve stenosis ranges from mild to severe. Some people with mild pulmonary valve stenosis don't have symptoms. They may need only occasional health checkups. Moderate and severe pulmonary valve stenosis may need a procedure to repair or replace the valve.
Pulmonary valve stenosis symptoms depend on how much blood flow is blocked. Some people with mild pulmonary stenosis do not have symptoms. Those with more-severe pulmonary stenosis may first notice symptoms while exercising.
Pulmonary valve stenosis symptoms may include:
Babies with pulmonary valve stenosis may have blue or gray skin due to low oxygen levels.
Talk to your health care provider if you or your child has:
Prompt diagnosis and treatment of pulmonary valve stenosis can help reduce the risk of complications.
Pulmonary valve stenosis usually results from a heart problem present at birth. The exact cause is unclear. The pulmonary valve doesn't develop properly as the baby is growing in the womb.
The pulmonary valve is made of three thin pieces of tissue called flaps, also called cusps. The cusps open and close with each heartbeat. They make sure blood moves in the right direction.
In pulmonary valve stenosis, one or more of the cusps may be stiff or thick. Sometimes the cusps may be joined together. That means they are fused. So the valve doesn't open fully. The smaller opening makes it harder for blood to leave the lower right heart chamber. Pressure increases inside the chamber. The increased pressure strains the heart. Eventually the lower right heart chamber wall gets thicker.
Things that may increase the risk of pulmonary valve stenosis include:
Possible complications of pulmonary stenosis include: