In mitral valve disease, the valve between the left heart chambers—left atrium and left ventricle—doesn’t function as intended. Under normal conditions, the mitral valve works as a one-way valve through the left heart chamber. Blood flows from the lungs into the left atrium and then through the mitral valve in the left ventricle. As the left ventricle contracts, it pumps blood out through the aorta to the rest of the body, then the mitral valve closes so blood doesn’t flow backwards into the left atrium.
Two types of mitral valve disease are: Mitral valve regurgitation, when the leaflets, or flaps of the mitral valve weaken causing blood to “leak” backward into the left atrium in the heart, and Mitral valve stenosis, a condition caused by the restricted narrowing of the mitral valve opening. Damage to the mitral valve can occur from a congenital defect, the natural process of aging, infection, or from a heart attack.
Damage to the mitral valve interferes with the normal passage of blood through the heart, and ultimately causes blood to back-up into the lungs. This can cause significant respiratory symptoms, and eventually congestive heart failure. It is for this reason that a damaged mitral valve may eventually need to be either repaired or replaced.
During the surgery, doctors repair the damaged valve and support it with a “ring” or replace the valve altogether with a “tissue” or “mechanical” valve.
Tissue and mechanical valves function similarly, however, there are distinct advantages and disadvantages of each. The advantage of mechanical valves, which are made from ceramic, is that they last forever. The disadvantage of mechanical valves is that they require anticoagulation with blood thinners for the remainder of a patient's life to keep blood clots from forming in the heart.
Tissue valves, made from cow or pig hearts, do not require formal anticoagulation. The disadvantage of tissue valves, however, is that they generally wear out after 12-15 years, at which time another operation would be required to replace the worn out valve.
Generally speaking, valve repair and replacement are open-heart surgeries.