The Dutch Asymptomatic Mitral Regurgitation Trial (Dutch AMR)

Dutch AMR; Early Mitral Valve Repair Versus Watchful Waiting in Asymptomatic Patients With Severe Organic Mitral Regurgitation; a Multicenter, Randomised Trial.

Leiden University Medical Center, The Interuniversity Cardiology Institute of the Netherlands, WCN, Dutch Network for Cardiovascular Research

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].

Mitral Valve Insufficiency, Mitral Valve Regurgitation, Asymptomatic Mitral Valve Regurgitation, Asymptomatic Mitral Valve Insufficiency, Mitral Valve Repair, Watchful Waiting

In case of watchful waiting a conservative treatment is performed, based on close monitoring of the patient for clear signs of deterioration that triggers facilitated surgery before left ventricular dysfunction is present.

Patients in the group of early mitral valve repair will be operated by way of routine mitral valve repair procedures in specialized centres.

Composite endpoint: cardiovascular mortality, congestive heart failure and hospitalization for nonfatal cardiovascular events

The primary outcome is defined as 'time to first event'. It concerns time to first event of the composite endpoint of cardiovascular mortality, congestive heart failure, non-fatal cardiovascular events requiring hospitalization, defined as: stroke/cerebrovascular accident (CVA), atrial fibrillation (permanent or requiring hospitalization) and/or reoperation after elective MV surgery.

Secondary outcome measures are the separate components of the composite primary endpoint: cardiovascular mortality, congestive heart failure, hospitalization for nonfatal cardiovascular events (stroke/cerebrovascular accident (CVA), AF (permanent or requiring hospitalization) and reoperation after elective MV surgery).

Secondary outcome measures are the separate components of the composite primary endpoint: cardiovascular mortality, congestive heart failure, hospitalization for nonfatal cardiovascular events (stroke/cerebrovascular accident (CVA), AF (permanent or requiring hospitalization) and reoperation after elective MV surgery).

Secondary outcome measures are the separate components of the composite primary endpoint: cardiovascular mortality, congestive heart failure, hospitalization for nonfatal cardiovascular events (stroke/cerebrovascular accident (CVA), AF (permanent or requiring hospitalization) and reoperation after elective MV surgery).

Secondary outcome measures total direct and indirect costs and cost-effectiveness at a minimum of 5 years.

Secondary outcome measures Cardiovascular Magnetic Resonance imaging (CMR) parameters at a minimum of 5 years.

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 for the need of facilitated surgery in the watchful waiting group will be determined at a minimum of 5 years.

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

Ling LH, Enriquez-Sarano M, Seward JB, Orszulak TA, Schaff HV, Bailey KR, Tajik AJ, Frye RL. Early surgery in patients with mitral regurgitation due to flail leaflets: a long-term outcome study. Circulation. 1997 Sep 16;96(6):1819-25. doi: 10.1161/01.cir.96.6.1819.

Enriquez-Sarano M, Avierinos JF, Messika-Zeitoun D, Detaint D, Capps M, Nkomo V, Scott C, Schaff HV, Tajik AJ. Quantitative determinants of the outcome of asymptomatic mitral regurgitation. N Engl J Med. 2005 Mar 3;352(9):875-83. doi: 10.1056/NEJMoa041451.

Chenot F, Montant P, Vancraeynest D, Pasquet A, Gerber B, Noirhomme PH, El Khoury G, Vanoverschelde JL. Long-term clinical outcome of mitral valve repair in asymptomatic severe mitral regurgitation. Eur J Cardiothorac Surg. 2009 Sep;36(3):539-45. doi: 10.1016/j.ejcts.2009.02.063. Epub 2009 Jul 25.

Rosenhek R, Rader F, Klaar U, Gabriel H, Krejc M, Kalbeck D, Schemper M, Maurer G, Baumgartner H. Outcome of watchful waiting in asymptomatic severe mitral regurgitation. Circulation. 2006 May 9;113(18):2238-44. doi: 10.1161/CIRCULATIONAHA.105.599175. Epub 2006 May 1.

Tietge WJ, de Heer LM, van Hessen MW, Jansen R, Bots ML, van Gilst W, Schalij M, Klautz RJ, Van den Brink RB, Van Herwerden LA, Doevendans PA, Chamuleau SA, Kluin J. Early mitral valve repair versus watchful waiting in patients with severe asymptomatic organic mitral regurgitation; rationale and design of the Dutch AMR trial, a multicenter, randomised trial. Neth Heart J. 2012 Mar;20(3):94-101. doi: 10.1007/s12471-012-0249-y.

Jansen R, Kluin J, Chamuleau SA. Research versus clinical practice in asymptomatic patients with severe organic mitral regurgitation and preserved LV function. J Am Coll Cardiol. 2014 Oct 14;64(15):1639-40. doi: 10.1016/j.jacc.2014.07.964. No abstract available.