Timing of mitral valve surgery.

Mitral valve surgery has changed considerably in the past decades and is now indicated mostly for pure or predominant mitral regurgitation. This is the result of the regression of rheumatic disease, of the efficacy of mitral balloon valvuloplasty for mitral stenosis, and of the aging of the population with increasing degenerative or ischaemic disease causing mitral regurgitation. Mitral regurgitation can be “organic” (that is, caused by intrinsic mitral disease such as rheumatic disease, ruptured chord, perforation of leaflet) or be “functional” (that is, where a normal valve regurgitates because of ventricular dysfunction). The timing of mitral surgery has remained one of the most vexing problems of clinical cardiology because symptoms can remain absent or minimal despite severe regurgitation caused by adaptive remodelling of left ventricle and atrium, or because of patient adaptation to the disease. However, recent advances in the understanding of the natural history of the disease and of the impact of left ventricular dysfunction on outcome, in the echocardiographic evaluation of mitral diseases and in the risk and success of mitral repair, have resulted in a widespread evolution towards earlier surgery.