The mitral valve is the valve that allows oxygenated blood to flow from the left atrium (LA) to the left ventricle (LV) during diastole.  During normal function, the mitral valve is closed in systole and prevents blood from flowing from the LV to the LA.  In mitral regurgitation (MR), the blood does flow in the reverse (from LV to LA) direction. MiCardia is primarily interested in two MR disease pathologies: functional, usually caused by myocardial infarction (MI)and degenerative, caused by valve degeneration which is the deterioration of the leaflets and/or sub-valvular apparatus.

     Functional MR related to ischemic heart disease (ischemic mitral regurgitation or IMR) is mainly triggered by left ventricular remodeling and LV dysfunction both caused by a myocardial infarction (MI).  In turn, the ventricle issues cause tethering of the mitral leaflets and annular dilatation, which are the mechanisms for the incompetence (poor coaptation). The functional MR, more specifically IMR, is typically (approximately 80% of the time) surgically treated with annuloplasty rings alone to reshape the annulus.  Annuloplasty addresses the mechanisms of the IMR but not necessarily the cause. The literature documents recurring IMR rates at anywhere from 10-30%, as the LV remodeling and/or dysfunction continues.

     The degenerative or organic MR is treated by repairing the leaflets and/or the subvalvular structures (papillary muscles and/or chordae).  An annuloplasty ring is also implanted to improve the integrity of the valve annulus shape.