Pulmonary Stenosis: Facts and Resources About the Congenital Heart Defect

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Pulmonary stenosis refers to the main pulmonary artery being narrowed at, above, or below the pulmonary valve. The narrowing may also happen in the pulmonary artery branches (left side or right). The large size of the pulmonary artery enables it to send oxygen-poor blood into the lungs to be encompassed with oxygen. Therefore, any blockages will cause trouble for the blood to travel to the lungs to pick up oxygen. To compensate for the narrowing, the right ventricle will increase pressure as it pumps blood into the pulmonary arteries. The high pressure could rise up to levels that may be damaging to the heart muscle.

Right Ventricle

The right ventricle is the lower right chamber of the heart. It contracts when the heart squeezes and forces blood out into the pulmonary artery. Between the right ventricle and the main pulmonary artery lies the pulmonary value. It actually sits on the way out of the heart. The valve is capable of preventing blood from leaking back into the heart between heartbeats.

Three Leaflets

There are three slender and flexible leaflets (tissues) that forms the pulmonary valve. The leaflets are arranged in a circle like a three-slice cake. When pulmonary stenosis is detected, the three leaflets either are fused or too thick or there happens to be fewer than three. Sometimes the diameter of the pulmonary valve is small or hypoplastic,. Thus, the valve becomes too narrow for the heart to pump blood with normal strength. Myocardium, the muscle of the right ventricle, gradually thickens to help out the right ventricle eject blood into the lungs. The heart ends up working harder to pump sufficient blood to go past any obstructions and into the body.

Different Locations Around the Pulmonary Valve

The location of where the pulmonary valve can occur on different spots. Subpulmonic stenosis is found below the valve caused by muscular bundles. Supravalvar pulmonic stenosis refers to stenosis located above the valve.

Other Names

Other names used for pulmonary stenosis are pulmonic stenosis or pulmonary valve stenosis. The pulmonary valve being obstructed can occur in different degrees: trivial, mild, moderate, severe or critical.

Types of Pulmonary Stenosis

There are four kinds of pulmonary stenosis. The first one to mention is branch peripheral pulmonic stenosis. It is the narrowing of the left or right pulmonary artery. Perhaps both sides may be narrowed. The second type is subvalvar (infundibular) pulmonary stenosis. This occurs when the muscle under the valve area is thickened and causing the narrowing of the outflow tract from the right ventricle. The third type is supravalvar pulmonary stenosis. This refers to the pulmonary artery just above the pulmonary valve being narrowed. The last kind is the valvar pulmonary stenosis, which happens when the valve leaflets are thickened and/or narrowed.

Occurs with Other Congenital Heart Defects

Pulmonary stenosis usually shows up in combination with other congenital heart defects including:

• Patent ductus arteriosus is a passageway between the pulmonary artery and the aorta that won’t close soon after birth.
• Pulmonary atresia is blood being hindered from flowing from the right ventricle into the pulmonary artery and towards to the lungs.
• Tetralogy of Fallot is a defect that includes four anomalies comprising of a right ventricle that is more forceful than others, a ventricular septal defect, an aorta that sits right over the ventricular septal defect, and pulmonary stenosis.
• Truncus arteriosus occurs when the heart forms one artery instead of the normal amount two.

Causes of Stenosis

When the pulmonary valve doesn’t properly grow during fetal development, the stenosis of it customary occurs. The babies that have the deformity often will also have other heart abnormalities that are usually detected at birth. So far, there’s not one known cause that can make the pulmonary artery to deviate its growth.

An artificial valve can cause older individuals to have pulmonary stenosis. Having other medical conditions can also affect the pumping of blood to the lungs. One disorder is carcinoid syndrome, which can happen when serotonin, a hormonal transmitter, is released from growth called carcinoid tumors located in the digestive system. Combination of signs and symptoms is involved for this syndrome, which include diarrhea and blushing of the skin. Heart valves can be problematic just because the presence of serotonin. Another disorder that can compromise the functioning of the pulmonary artery is rheumatic fever. It is a complication of an infection such as scarlet fever or strep throat caused by streptococcus bacteria.

Lastly, Noonan’s syndrome, Holt-Oram syndrome, and Leopard syndrome can cause congenital valvular malformations that involves stenosis of the pulmonic valves.

Resources About Pulmonary Stenosis

Cleveland Clinic
The Children’s Hospital of Philadelphia
Cincinnati’s Children
Lucile Packard Children’s Hospital at Stanford
Mayo Clinic

Resource by S.Lee

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