The Dutch Asymptomatic Mitral Regurgitation Trial (Dutch AMR)

• Composite endpoint: cardiovascular mortality, congestive heart failure and hospitalization for nonfatal cardiovascular events [ Time Frame: Min. 5 years ] [ Designated as safety issue: Yes ]
  The primary outcome is defined as time to first event of the composite endpoint of cardiovascular mortality, congestive heart failure and hospitalization for nonfatal cardiovascular events
  
  

• Cardiovascular mortality [ Time Frame: Min. 5 years ] [ Designated as safety issue: Yes ]
  Secondary outcome measures the separate component cardiovascular mortality at a minimum of 5 years.
  
  
• Congestive heart failure [ Time Frame: Min. 5 years ] [ Designated as safety issue: Yes ]
  Secondary outcome measures the separate component congestive heart failure at a minimum of 5 years.
  
  
• Hospitalization for nonfatal cardiovascular events [ Time Frame: Min. 5 years ] [ Designated as safety issue: Yes ]
  Secondary outcome measures the separate component hospitalization for nonfatal cardiovascular events (including but not limited to acute coronary syndrome, arrhythmia and heart surgery) at a minimum of 5 years.
  
  
• All-cause mortality [ Time Frame: Min. 5 years ] [ Designated as safety issue: Yes ]
  Secondary outcome measures the incidence of all-cause mortality at a minimum of 5 years.
  
  
• Costs and effectiveness [ Time Frame: Min. 5 years ] [ Designated as safety issue: No ]
  Secondary outcome measures total direct and indirect costs and cost-effectiveness at a minimum of 5 years.
  
  
• Quality of life [ Time Frame: Min. 5 years ] [ Designated as safety issue: No ]
  Secondary outcome measures health-related quality of life at a minimum of 5 years.
  
  
• Echocardiographic parameters [ Time Frame: Min. 5 years ] [ Designated as safety issue: No ]
  Secondary outcome measures echocardiographic parameters at a minimum of 5 years.
  
  
• CMR parameters [ Time Frame: Min. 5 years. ] [ Designated as safety issue: No ]
  Secondary outcome measures Cardiovascular Magnetic Resonance imaging (CMR)parameters (left ventricular function, left atrial dimensions, pulmonary hypertension) at a minimum of 5 years.
  
  
• Atrial fibrillation [ Time Frame: Min. 5 years ] [ Designated as safety issue: No ]
  Secondary outcome measures the incidence of asymptomatic atrial fibrillation at a minimum of 5 years.
  
  
• Exercise test parameters [ Time Frame: Min. 5 years. ] [ Designated as safety issue: No ]
  Secondary outcome measures exercise test parameters at a minimum of 5 years.
  
  
• BNP [ Time Frame: Min. 5 years ] [ Designated as safety issue: No ]
  Secondary outcome measures brain natriuretic peptide (BNP) plasma levels at a minimum of 5 years.
  
  

• Surgery complication rate [ Time Frame: Min. 5 years ] [ Designated as safety issue: Yes ]
  The complication rate in the mitral valve surgery group (e.g. re-operation for bleeding, pneumonia, residual or recurrent mitral valve regurgitation) will be determined at a minimum of 5 years.
  
  
• Rate of surgery [ Time Frame: Min. 5 years ] [ Designated as safety issue: Yes ]
  Rate of surgery in the watchful waiting group will be determined at a minimum of 5 years.
  
  

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].