Doctors replace heart valves by accessing the heart through either open or minimally invasive surgery and use a machine to take over the work of the heart while the old valve is replaced by an artificial or donated valve, states MedlinePlus. It is generally the aortic valve that requires replacement.
Doctors perform heart valve replacement surgery when the valve is too damaged to be repaired, according to MedlinePlus. The aortic valve can never be repaired, so if it is damaged it must always be replaced. Each type of valve replacement has advantages and disadvantages. Artificial valves are made of ceramic or metal and last a long time, but a patient with an artificial heart valve must take medicine to thin the blood for as long as it is in place. A donated valve is made of either human or animal tissue and does not necessarily require blood thinners, but it only lasts between 12 and 15 years before it must be replaced.
The two types of problems that occur with heart valves are stenosis and regurgitation, MedlinePlus says. Stenosis is when the valve does not open sufficiently, and blood flow is restricted. Regurgitation occurs when the valve does not close completely, so blood can flow backward.