The Dutch Asymptomatic Mitral Regurgitation Trial
The Dutch Asymptomatic Mitral Regurgitation Trial
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.
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].
Inclusion Criteria:

 -  Asymptomatic

 -  Severe organic mitral valve regurgitation.

 -  Preserved left ventricular function (left ventricular ejection fraction >60% and left
 ventricular end-systolic dimension ≤45 mm)

 -  The likelihood of MV repair should be more than 90% determined by the local heart team
 with a cardiologist and cardiothoracic surgeon

 Exclusion Criteria:

 -  Pulmonary hypertension (>50 mmHg at rest)

 -  Atrial fibrillation

 -  Physical inability as determined by the heart team to undergo surgery

 -  Other life-threatening morbidity

 -  Higher expected surgical risks in advance, according to the dedicated heart team

 -  Moderate to severe kidney disease (eGFR less than 30 mL/min)

 -  Flail leaflet together with a left ventricular end systolic diameter (LVESD) >40 mm