Assessment and Treatment for Secondary Mitral Regurgitation

The assessment and treatment for secondary mitral regurgitation (MR) are based on the concepts different from those for primary MR. The main etiology of traditional secondary MR is mitral leaflet tethering-tenting occurring from left ventricular dilatation and systolic dysfunction. The origin of secondary MR usually takes a transverse direction along the mitral leaflets' coaptation. Consequently, the Doppler-derived volumetric method should be selected for the echocardiographic quantitative analysis of the secondary MR rather than the proximal isovelocity surface area method. In general, the strong medical therapies are required in heart failure patients with significant secondary MR. Mitral valve surgery may be also considered for patients with severe secondary MR with heart failure symptoms despite the optimal medical therapies. Concomitant mitral valve surgery is more reasonable in patients with coronary artery disease and severe secondary MR at the time of coronary artery bypass grafting (CABG). It is still controversial whether concomitant mitral valve surgery should be performed in patients with coronary artery disease and moderate secondary MR at the time of CABG. Low-dose dobutamine stress echocardiography or exercise stress echocardiography may be helpful to address this issue. For secondary MR seen in patients with atrial fibrillation and left atrial dilatation despite havinf preserved left ventricular ejection fraction, mitral annuloplasty would be the primary treatment.