A normal heart has four valves that are like one-way doors. These “doors” open and shut to control the blood flow to and from the heart. The four valves are the:
- Aortic valve
- Pulmonary valve
- Mitral valve
- Tricuspid valve
Each valve has leaflets — either two or three depending on the type of valve — that open and close to let the blood go through and to stop it from going back in the wrong direction.
In some congenital heart defects, one or more of the valves does not work properly. Some infections and diseases, like endocarditis, rhuematic fever and Kawasaki disease, can damage the heart valves, too. The two most common problems with the valves are narrowing of the valves and leaky valves. Sometimes the valve is extremely narrow or missing, and there is no opening where there should be one (atresia).
Cardiologists treat heart-valve problems differently depending on how severe the problem is. Some children with heart-valve problems have no symptoms for many years and will not need surgery. Other times, cardiologists will prescribe medicine to treat valve disease and to prevent more damage to the valves.
In severe cases, heart surgeons may need to repair or replace the valve. Valve repair is more common for the tricuspid valve and the mitral valve. In some cases, the repair can be done without open-chest surgery, but this is typically not an option if your child has other heart problems that need to be fixed at the same time. Valve replacement is done when the valve cannot be repaired. The old valve is removed, and an artificial valve is put in its place.
There are two types of artificial valves: tissue valves and mechanical valves. Tissue valves are made from pig heart valves or cow cardiac tissue. Both of these work a lot like human heart valves. Another option is a homograft, which is a human valve from a human donor.
A benefit to tissue valves is that people who get them often don’t have to be on blood-thinning medication (anti-coagulants) for life. However, a disadvantage is that tissue valves may not last as long as mechanical ones. Mechanical valves are made to work just like a normal heart valve, and they are designed to last for life.
In children, however, the valve may need to be replaced as the child grows because it cannot grow with the child. People who get mechanical valves will need to take anti-coagulants to prevent blood clots from forming on the valve. Today, cardiologists are able to do some replacements for pulmonary valves and aortic valves through cardiac catheterizations, but this is mostly done in adults. Once children reach a certain size, the pulmonary valve may be able to be replaced via cardiac catheterization rather than open-chest surgery.