The valves of the heart are made up of leaflets that separate and come together to regulate the flow of blood through the heart. Damage or scarring of the valve can happen because of birth defects, rheumatic fever, infections or a buildup of calcium deposits. When the heart valves do not open or close properly, the heart has to pump harder to get oxygen-rich blood to the body. This can weaken the heart, causing pain, shortness of breath, dizziness or other symptoms.

Sometimes medicines can be used to treat damaged heart valves. If this fails, surgery is needed.

Valve surgery is most often needed because of:

• Stenosis, which occurs when the leaflets thicken, stiffen or stick together. The leaflets are not able to open up properly, so only a small amount of blood can flow through the valve.
  
• Regurgitation (also known as valve insufficiency or incompetence) occurs when the valve does not close, so blood leaks backward into the chamber of the heart that should be emptying.
  

Every year, about a quarter of a million heart valve operations are done around the world. Most are done to repair or replace the mitral or aortic valves. These are on the left side of the heart, which works the hardest. Sometimes more than one valve needs to be repaired or replaced.

Valve repair involves the surgeon rebuilding the valve so that it works better. This can usually be done on valve defects or less damaged valves.

Valve repair surgery includes:

• Commissurotomy, in which thickened or stuck valves are opened up by cutting the points where the leaflets meet
• Valvuloplasty, in which a ring is attached around the outside of the opening of the valve to give it more support and help it close more tightly
• Reshaping, in which the surgeon cuts away part of a leaflet then sews it back together so that the valve can close properly
• Decalcification, in which calcium that has built up from the leaflets is removed so the leaflets can close properly
• Replacing or shortening the cords (chordae tendineae and the papillary muscles) that support the valve. When the cords are the right length, the valve can close properly.
  
• Patching, holes or tears in the leaflets

Valve replacement is done when the damage to the valve is too severe to repair. This surgery is most often done to treat aortic valves or seriously damaged mitral valves. It is also done when valve disease is life-threatening. The replacement can be done with a:

• Mechanical valve made of plastic, carbon or metal. Mechanical valves are strong and long lasting. Because blood tends to stick to mechanical valves and create blood clots, it is necessary to take blood-thinning drugs (anticoagulants) for the rest of your life if you have one of these valves. Because these drugs can increase the risk of bleeding in your body, be sure to wear a medical alert bracelet and tell your doctor and dentist that you are taking blood thinners.
• Biological valve made from animal tissue (called a xenograft ) or taken from a human donated heart (called an allograft or homograft Sometimes, a patient's own tissue can be used for valve replacement (called an autograft ). Patients with biological valves usually do not need to take blood-thinning medicines. A biological valve needs to be replaced about every 10 years - even more often in a child or young adult. These valves are used most often in elderly patients.

Valve repair and replacement surgery requires your heart to be stopped and a heart-lung machine to be used.

After you are hooked up to the heart-lung machine, your heart is stopped and cooled. Next, a cut is made into the heart or aorta, depending on which valve is being repaired or replaced. Once the surgeon has finished the repair or replacement, the heart is then restarted, and you are disconnected from the heart-lung machine.

The surgery takes two to four or more hours, depending on how many valves are repaired or replaced.

In some cases, minimally invasive valve surgery can be used to repair or replace a valve. Minimally invasive surgical techniques usually involve less pain and faster healing. These techniques, however, cannot be used in all cases.