Management of asymptomatic, severe mitral regurgitation

In chronic, severe mitral regurgitation (MR), cardiac function can remain well compensated and patients can remain asymptomatic for many years. Eventually, in most patients, the originally favorable loading conditions give way to unfavorable remodeling, which results in left ventricular (LV) dysfunction and dilation, and ultimately symptoms of pulmonary congestion. Symptomatic, chronic severe MR is a clear indication for surgical correction. However, the optimal management of asymptomatic patients is less clear. While asymptomatic severe MR patients who have developed LV dysfunction or LV dilation warrant surgery, the decision to operate without these findings hinges on the presence of other clinical sequelae, such as atrial arrhythmias and pulmonary hypertension, and on the likelihood of successful mitral valve repair. Controversy exists as to the optimal approach to patients without any of these objective triggers, with some evidence supporting earlier prophylactic surgery and other evidence supporting a "watch and wait" approach. It is our conviction that in absence of an established guideline-based indication for surgical correction, for most asymptomatic patients with chronic severe MR, the preferred approach is close monitoring with serial echocardiography for development of symptoms or other clinical sequelae. However, it is reasonable to consider earlier surgical correction in select asymptomatic patients in whom there is a high likelihood of successful mitral valve repair. In this paper, we comprehensively review all guideline-based management of asymptomatic chronic severe MR, and discuss new evidence that impacts clinical decision-making in these patients.