What is Pulmonary Stenosis
The lungs can only do their job when all the body's systems are working properly. Their function is particularly affected by anything that compromises the heart's function. If something is wrong with the heart, the lungs' capability of oxygenating blood and clearing carbon dioxide out becomes impaired.
Normal heart function involves the four ventricles (chambers) of the heart working together to pump oxygen-poor blood to the lungs and oxygenated blood out to the rest of the body. The pulmonary artery is responsible for delivering oxygen-poor blood to the lungs. The aorta is responsible for delivering the oxygenated blood to the rest of the body.
A normal heart's structure includes valves at the junctions between the particular ventricles and the arteries so that blood only flows one way. In the case of the pulmonary stenosis, it is the pulmonary valve that is malformed and unable to open completely.
A normal valve is comprised of three "leaflets." There are three main issues with these leaflets that can affect optimal blood flow and heart and lung function:
- a valve with only one or two leaflets instead of three
- a valve where the leaflets are partially fused together
- a valve with thick leaflets that cannot open all the way
The severity of pulmonary stenosis and the subsequent symptoms varies according to the amount of blockage. For example, the greater the extent of the obstruction, the harder the heart has to work and the higher a person's blood pressure will be.
Pulmonary stenosis is a congenital disease--that is, it is present at birth. Since the heart develops during the first eight weeks of pregnancy, it is assumed that something during that process does not happen as it should. In the vast majority of cases, there is no clear reason why such a deformity occurs. In the smaller amount of cases, the deformity is genetic.
"Pulmonary stenosis is a component of half of all complex congenital heart defects. Pulmonary stenosis is the second most common congenital heart defect, composing 5 to 10 percent of all cases" (www.childrenshospital.org).