Pulmonary valve stenosis: causes and treatment

The pulmonary valve sits between the right ventricle and the pulmonary artery. It opens to let blood flow to the lungs and closes to stop it flowing backwards. In stenosis the valve and the area around it are narrow. Over time the muscle of the right ventricle can become thicker as it works harder, in the same way other muscles thicken with extra work, as the Leeds leaflet explains.

The BHF describes three types. Valvular stenosis, where the valve itself is narrow, is the most common. Subvalvular stenosis is a narrowing before the valve, which can happen when the heart muscle is thickened. Supravalvular stenosis is a narrowing in the pulmonary artery, and the BHF says it is more likely with a genetic condition such as Williams syndrome. Some people also have an atrial or ventricular septal defect.

Severity describes how much the narrowing limits flow. The BHF says that in mild stenosis enough blood is pumped to the lungs, whereas in moderate or severe stenosis the lungs do not get enough blood and the heart has to work harder. Leeds says that if the narrowing is mild the heart copes very well, but if it is very severe the heart cannot pump normally, which can limit how much exercise a child manages.

Over a long time, a heart that works harder can develop thickened muscle, heart failure, an irregular rhythm or Eisenmenger syndrome, according to the BHF. This is why moderate and severe cases are treated and mild cases are checked regularly.

The BHF explains that most people with pulmonary valve stenosis have no symptoms except a heart murmur, a swishing sound that a doctor hears with a stethoscope. In severe cases there can be more tiredness than usual. A murmur does not always mean a heart problem, but a persistent one is checked.

Most people are diagnosed shortly after birth during a routine health check, though some adults are found during a health check or because of symptoms. The BHF lists an ECG, an echocardiogram, a chest X-ray, CT, MRI, a stress test, blood tests and sometimes a cardiac catheter study. Leeds says an echocardiogram is required to look at the valve. These tests do not hurt.

• Echocardiogram, the key test for seeing the valve and measuring flow

• ECG to check the heart rhythm and signs of muscle thickening

• Chest X-ray, and sometimes CT or MRI for more detail

• Cardiac catheter study in some cases

• Exercise stress test for older children and adults

The BHF states that it is not known why pulmonary valve stenosis happens. It develops as the heart forms before birth. Some forms are linked to a genetic condition, such as Williams syndrome in the supravalvular type, but many children have no other health problems.

The NHS adds, about congenital heart disease in general, that problems arise while the heart is forming in the womb and that often there is no clear reason. Parents often search for something they may have done. The sources do not point to any single cause for most children.

Mild stenosis usually needs only regular appointments. For stenosis that needs treatment, the BHF says it is usually treated when you are a baby, by balloon valvuloplasty or open heart surgery. Leeds explains that balloon valvuloplasty is done under general anaesthetic: a catheter with a collapsed balloon is passed from a vein at the top of the leg across the narrowed valve and inflated under X-ray guidance.

It is often a day case or a one-night stay, according to Leeds, and the BHF says a hospital stay of 1 or 2 days is usual. Sometimes the narrowing is only partly relieved and the procedure is repeated. Because thickened muscle can itself cause narrowing, it can take a few weeks to see the full result, and a small proportion of patients need surgery to remove some of the muscle.

Open-heart surgery may be needed when the valve cannot be stretched. The surgeon can enlarge the area around the valve or replace it. The BHF gives a usual hospital stay of 5 to 7 days, and Leeds says about 5 days for a child.

Leeds explains that after any treatment the pulmonary valve never works completely normally and will leak to some extent. This is pulmonary regurgitation. It is usually well tolerated for years, but there is a small chance of needing a valve repair or replacement later in life. Children who needed no treatment by adulthood usually never do, though in rare cases the valve narrows in later adult life.

The BHF says most people who have treatment or have mild stenosis can live well, and it is important to keep appointments even when well. Exercise advice depends on severity: generally people with moderate stenosis should avoid high-intensity exercise and sports like climbing or gymnastics, and with severe stenosis only low-intensity exercise. Anyone planning a pregnancy should speak to their doctor first.