Severe asymptomatic organic mitral valve (MV) regurgitation with preserved left ventricular (LV) function is a challenging clinical entity as data on the recommended treatment strategy for these patients are scarce and conflicting, which is reflected in current guidelines. European guidelines advocate a more conservative strategy i.e. watchful waiting, with yearly echocardiography, whilst American guidelines are more in favour of early surgery to reconstruct the MV, i.e. MV repair (in contrast to MV replacement) in order to prevent future LV dysfunction and complaints.~A number of non-randomised trials show a favourable outcome of early surgery and the early surgery strategy has shown to be associated with improved long-term survival, decreased cardiac mortality and decreased morbidity compared with the conservative management [citations 1-3]. On the other hand, non-randomised trials describe also that a conservative strategy (i.e. watchful waiting) can be safely accomplished. If facilitated surgery is performed in this population it has proven to be eventually associated with good perioperative and postoperative outcome in 50% of the patients at 10 years when careful follow-up is being carried out [citation 4]. Non-randomised trials inherently have a number of drawbacks. A randomised trial comparing both strategies and objectivising the best treatment strategy has never been performed.~The Dutch AMR (Asymptomatic Mitral Regurgitation) trial is a multicenter, prospective, randomised trial comparing early MV repair versus watchful waiting in asymptomatic patients with severe organic MV regurgitation and preserved LV function [citation 5, 6].
The purpose of this study is to compare early mitral valve repair versus a watchful waiting strategy in asymptomatic patients with severe organic mitral valve regurgitation and preserved left ventricular function.