The mitral valve has two leaflets and is located between the left atrium and left ventricle of the heart. The valve opens to allow blood to flow from the atrium to the ventricle and closes (coapts) to prevent blood from flowing backwards from the ventricle to the atrium.
Normal Mitral Valve
Figure 1: Normal mitral valve
Mitral Regurgitation (MR) or mitral valve insufficiency develops when the mitral valve leaflets fail to coapt properly and blood leaks back into the left atrium of the heart. Any disorder that weakens or damages the mitral valve or the left ventricle may lead to mitral regurgitation. MR can be caused by damage to the valve itself, or as a result of an underlying cardiac condition which triggers changes to the size and/or shape of the heart (remodeling). MR is classified in one of two categories:
- Structural / Degenerative Mitral Regurgitation
If the valve itself is structurally abnormal (such as Mitral Valve Prolapse Syndrome or a congenitally malformed valve), has been damaged (as a result of infection or by rheumatic fever), or is “degenerating” due to the normal aging process, the mitral regurgitation is considered structural or degenerative.
- Functional Mitral Regurgitation (FMR)
If the valve is structurally normal (functional), but leaks because of changes to the size and/or shape of the heart (remodeling) or damage to the heart muscle from coronary artery disease or a heart attack, the mitral regurgitation is considered functional.
FMR is a Ventricular Disease
FMR is considered a ventricular disease because it occurs in the context of left ventricular (LV) function and geometry (see below). As the condition of FMR worsens, larger volumes of blood begin to leak back into the atrium which decreases the amount of blood flow to the body. To compensate, the heart works harder to pump the extra blood (volume overload). Ultimately, the LV continues to dilate, further compromising leaflet coaptation and thus setting up a continuing loop of increased LV dilatation leading to increased FMR
- Figure 2: An initial event produces LV dysfunction manifested by either global or localized wall motion abnormalities
- Figure 3: These changes cause annular dilatation and/or LV dysfunction leading to subvalvular geometric changes
- Figure 4: The geometric changes compromise leaflet coaptation resulting in FMR
Treating FMR is Important
The incidence of FMR continues to be a growing concern in the clinical community. Literature suggests that 10-20% of patients who present for coronary artery bypass procedures (CABG) also have MR. If the condition persists, the patient can also develop atrial fibrillation and potentially congestive heart failure, leading to shortness of breadth, dizziness, chest pain, and fatigue. In addition, the literature indicates that 30-50% of later stage congestive heart failure patients (Class III or IV) have MR with estimated survival at 6 years steadily decreasing from 80% in patients with no MR down to 50% in patients with MR grade 2-4.
Current Treatment Options
The most common surgical procedure to repair a leaky mitral valve is placement of an annuloplasty ring. In this procedure, a surgeon performs a sternotomy (opens chest), opens the atrium, and sews in an annuloplasty ring to reduce the diameter of the annulus and thus improve leaflet coaptation. The patient must be put on cardiopulmonary bypass (stopping the heart) because of the invasive nature of this procedure. In combination with CABG, this procedure can have up to a 16% mortality rate and a complication rate that some surgeons estimate at over 25%.
The Coapsys System is an innovative technology designed to provide a complete, long-term solution for the treatment of FMR. The therapeutic goals of the Coapsys device are to:
- Reduce FMR acutely and long-term
- Reshape the heart to its more natural size and shape
- Improve patient’s quality of life