Notice there are two "leaflets" to the mitral valve:

1) anterior leaflet

2) posterior leaflet

Mitral Stenosis

Like any valve, the mitral valve can become either blocked ("stenosis") or it can leak ("insufficiency").

Mitral stenosis is fairly rare nowadays, since the advent of antibiotics.  Previously, mitral stenosis was the most common valvular disorder in adults due to Rheumatic fever:

In Rheumatic heart disease, the mitral valve leaflets become thickened and begin to fuse to each other.  Eventually the valve becomes calcified and can no longer be repaired.  Therefore, most patients with mitral valve stenosis need their valve replaced.  As with aortic valves, the choices for replacement of the mitral valve are "mechanical prosthetic valves" versus "tissue prosthetic valves" (see discussion under "Aortic Valve")

Mitral Insufficiency

By far, the most common mitral valve problem today is mitral insufficiency  --a leaking mitral valve.  Here's an animation of a leaking mitral valve:

There are several reasons why the mitral valve may be leaking:

1) Mitral Valve Prolapse:  Though a commonly used term, it can apply to several different lesions.  The pathology can range from simply having a slight excess or thinning of a particular leaflet, to having a diseased process effecting both leaftlets (Barlow's syndrome)  to having a torn leaftlet or support structure (known as myxomatous degeneration of the valve).  These are the most common indications for Mitral Valve Repair.

2) Ischemic Cardiomyopathy:  This is a fancy term that also applies to several different lesions.  The most common is a patient with not enough blood supply to an area of heart muscle that provides the support structures to the mitral valve.  In this instance, coronary artery bypass surgery may be all that is needed.  By supplying fresh blood to the muscle, the function of the valve returns to normal.  However, when the leaking is severe the valve can often be repaired.

A very serious complication from a heart attack can be the sudden loss of blood supply to the specialized muscle that holds the support structures to the mitral valve, the papillary muscles.  In this instance, the papillary muscle ruptures and the patient has immediate congestive heart failure as a result of sudden, torrential leaking of blood across the mitral valve.  Though there are reports of repairing papillary muscles, most surgeons will opt to replace the mitral valve in this very serious, life-saving emergency operation.

Lastly, a patient may slowly develop an enlarged heart from chronic heart failure.  In this instance, as the heart enlarges the mitral valve becomes incompetent.  The valve itself is completely normal, but the opening becomes gapping because of the ever enlarging heart.  This is a controversial area.  Some surgeons will opt for repair, while others will opt for replacement.

3) Rheumatic Heart Disease:  When a valve becomes blocked, it can also leak.  The reason is simple:  the valve is blocked but stays in a fixed position, never completely closing and never completely opening.  As discussed above, almost all of these valves will need to be replaced.

The history of mitral valve repair is quite interesting.  Dr. Alain Carpentier began developing the techniques of mitral valve repair in Paris in the early 1970's.

Below is a picture of me with Dr. Carpentier (next to me).  Behind us is Dr. Charles Benoit, the Chief at the Geisinger Medical Center in Danville, Pennsylvania.

There were two reasons Professor Carpentier developed these techniques.

First, the early results of mitral valve replacement with prosthetic valves was poor.  Unfortunately, surgeons didn't fully understand the anatomy of the mitral valve at that time, especially the importance of the so-called sub-valvular apparatus (the papillary muscle and the attachments holding the mitral leaflets).

As a result, when surgeons placed prosthetic valves in the early days of heart surgery, they often used to cut out the leaflets and their attachments.  This changed the geometry of the pumping chamber of the heart and resulted in a weakened heart muscle.  Many of these patients died of heart failure after their valves were successfully replaced.

In addition, the use of blood thinners was not as standardized as it is today.  Patients had many complications such as clotting of the prosthetic valves, stokes, and so on.

Second, Professor Carpentier began treating many poor patients from throughout Europe and Africa who suffered from Rheumatic heart disease and who would most certainly be non-compliant in taking their medications once they returned home.  Therefore, regulating blood thinners in these patients was simply out of the question.  By repairing their valves, these patients would not need blood thinners and would more likely survive with little medical follow-up.

Mitral valve repair, therefore is physiologically better than mitral valve replacement.  As a result, we try to repair the mitral valve whenever possible.

Is mitral valve replacement bad?  No.  As a follow-up to the development of mitral valve repair, an interesting parallel history occurred with mitral valve replacement with prosthetic valves:  Surgeons better understood the anatomy of the mitral valve and began preserving the sub-valvular structures when mitral valve was replaced.  Consequently, the results improved.  Also, blood thinning therapy has also become standardized.  Therefore, patients now do exceptionally well with prosthetic mitral valves.

So, is it better to repair or replace the mitral valve?  Even though mitral valve replacement with a prosthetic valve is now completely safe, it is still always preferable to have the valve repaired if possible.

The reasons still remain the same.  A repaired valve is physiologically closer to normal and the patient can avoid blood thinners.  Though blood thinners are generally safe, they do have about a 2% yearly risk of complications.  Plus, if you are on blood thinners, you have to have your blood level checked regularly.

But, mitral valve repair can be a complex procedure.  Not every mitral valve can be repaired and not every repair works.

So, if you end up with a mitral valve replacement, it may be just what you need.  You should not look upon this as a failure.

In my hands, approximately 90% of patients with mitral valve insufficiency will receive a repair.  However, every patient and every valve is different.  I prepare every patient for the possibility of needing a replacement valve even though I am going into the operation planning on repairing their valve.

I have had the privilege of taking multiple courses on mitral valve repair both in the United States and in Paris.  I've watched many of the true pioneers:  Dr. Alain Carpentier, Dr. Carlos Duran, Dr. Delos Cosgrove, and Dr. Christophe Acar.

Dr. Carpentier

Dr. Acar, Dr. Singer (me), and Dr. Duran

   Mitral valve repair remains one of the most interesting and challenging open heart operations that we perform.

CLICK HERE and see an interesting case - an example of Mitral Valve Repair!