Heart valves can malfunction in two ways. They can be stuck in a more closed position, so the flow through the valve will be restricted. It can also be stuck in a more open way, in which case the blood can leak back through the valve.

The heart valves control the flow of blood by helping it move in one direction through your heart and body. If a valve isn’t working properly, this blood flow and the blood vessels that carry oxygen throughout the body are affected

Most commonly, heart valve replacement is a major open-heart surgery with a recovery of several weeks. During this procedure, the doctor makes an incision in the chest, and circulates blood outside of the body using a machine to add oxygen to it.

The newer procedure, which is a percutaneous valve procedure (otherwise known as a TAVI), is less invasive, but isn’t performed at as many hospitals.

The most common tissues used for heart valve replacement are cow tissue, made of the heart sac of the cow, or pig valve, and sometimes a combination of both. Other options are a cadaver valve, or transferring your own valve from another part of your heart.