Is valve surgery indicated in patients with severe mitral regurgitation even if they are asymptomatic?

There is a natural reluctance among clinicians to recommend surgery in asymptomatic patients with cardiac disease and in patients with stenotic disease of the mitral and aortic valves; this instinct will mislead us very rarely. However, among patients with chronic volume overload of the LV, this rule-of-thumb does not always apply. For truly asymptomatic patients with severe MR who clearly have normal LV function, continued medical therapy with serial monitoring of LV dynamics is a prudent alternative to the small risk of corrective surgery. However, the major challenge in addressing this problem is the definition and detection of LV dysfunction in chronic MR. Thus, for MR patients with questionable impairment of myocardial function (generally those with an SEF between 0.55 and 0.70), an examination of chamber dimensions and particularly stress-shortening relations may be necessary to detect early LV dysfunction. Should LV dysfunction be identified or should serial studies indicate an adverse trend in LV performance, a strong case can be made for proceeding with surgery. Patients with an SEF of less than 0.55 must be assumed to have LV dysfunction and analogous data from patients with chronic AR suggest that a satisfactory surgical result may be achieved if the duration of LV dysfunction is brief. Those patients with chronic MR whose disease is likely to be amenable to mitral valve repair rather than valve replacement deserve a lower threshold for corrective surgery.