Mitral valve repair

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Mitral valve repair is a cardiac surgery procedure performed by cardiac surgeons to treat stenosis (narrowing) or regurgitation (leakage) of the mitral valve. The mitral valve is the "inflow valve" for the left side of the heart. Blood flows from the lungs, where it picks up oxygen, through the pulmonary veins, to the left atrium of the heart. After the left atrium fills with blood, the mitral valve allows blood to flow from the left atrium into the heart's main pumping chamber called the left ventricle. It then closes to keep blood from leaking back into the left atrium or lungs when the ventricle contracts (squeezes) to push blood out to the body. It has two flaps, or leaflets.

The techniques of mitral valve repair include inserting a cloth-covered ring around the valve to bring the leaflets into contact with each other (annuloplasty), removal of redundant/loose segments of the leaflets (quadrangular resection), re-suspension of the leaflets with artificial (Gore-Tex) cords. More recently the Alfieri stitch (or "bow-tie") has been adapted to allow percutaneous repair in select patients.

Procedures on the mitral valve usually require a median sternotomy, but advances in non-invasive methods (such as keyhole surgery) allow surgery without a sternotomy (and resulting pain and scar). Minimally invasive mitral valve surgery is much more technically demanding and may involve higher risk.

Occasionally, the mitral valve is abnormal from birth (congenital). More often the mitral valve becomes abnormal with age (degenerative) or as a result of rheumatic fever. In rare instances the mitral valve can be destroyed by infection or a bacterial endocarditis. Mitral regurgitation may also occur as a result of ischemic heart disease (coronary artery disease).

The development of the heart-lung machine in the 1950s paved the way for replacement of the mitral valve with an artificial valve in the 1960s. For decades, mitral valve replacement was the standard operation for a patient with a diseased mitral valve.

There are significant downsides to an prosthetic mitral valve. Infection of the artificial valve can occur, which is very dangerous. Patients with mechanical heart valves are required to take blood thinners for the rest of their lives and are at risk for bleeding complications. Artificial tissue valves will last between 10 and 15 years, placing the patient at risk of a second operation to replace the valve. The risk of stroke with an artificial mitral valve is significant (approximately 1 % per year).

In the last two decades, some surgeons have embraced surgical techniques to repair, rather than replace, the mitral valve. These techniques were pioneered by a French heart surgeon, Dr. Alain F. Carpentier, who published a landmark paper in the mid 1980s entitled The French Correction.