Mitral Valve Repair in Asymptomatic Patients With Severe Mitral Regurgitation: Pushing Past the Tipping Point Rakesh M. Suri, MD, DPhil, Hartzell V. Schaff, MD, and Maurice Enriquez-Sarano, MD Degenerative mitral valve regurgitation (MR) is the one of the most frequent valvular heart conditions in the Western world and is increasingly recognized as an important preventable cause of chronic heart failure. This condition also represents the most common indication for mitral surgery and is of particular interest because the mitral valve can be repaired in most patients with very low surgical risk. Historical single-center studies have supported the performance of “early mitral valve repair” in asymptomatic patients with severe degenerative MR to normalize survival and improve late outcomes. Emerging recent evidence further indicates for the first time that the prompt surgical correction of severe MR due to flail mitral leaflets within 3 months following diagnosis in asymptomatic patients without classical Class I indications (symptoms or left ventricular dysfunction) conveys a 40% decrease in the risk of late death and a 60% diminution in heart failure incidence. A 10-point rationale based on the weight of rapidly accumulating clinical data, supports the performance of early mitral valve repair even in the absence of symptoms, left ventricular dysfunction, or guideline-based triggers; when effective operations can be provided using conventional or minimally invasive techniques at very low surgical risk. Semin Thoracic Surg 26:95–101 I 2014 Elsevier Inc. All rights reserved. INTRODUCTION Degenerative mitral valve regurgitation (MR) is a frequent cause of heart valve disease in young, otherwise healthy patients (1%-3% of the Western population) and is being increasingly recognized as an important prevent- able cause of chronic heart failure. 1 This condition represents the most frequent indication for mitral surgery in contemporary practice and is unique among heart valve lesions in that the degenerative mitral valve (ie, flail or prolapse) can be surgically repaired in most patients. Mitral valve repair of degenerative MR not only amelio- rates and prevents heart failure symptoms but has also been proven to restore normal life expectancy. 2-5 How- ever, despite a growing body of evidence, discordance persists in mainstream clinical practice regarding the timing of recommendation and performance of surgery following the initial diagnosis of severe MR, 6-8 partic- ularly in patients without Class I indications for mitral surgery, that is, those with no or minimal symptoms and absence of overt left ventricular (LV) dysfunction. The recent 2014 AHA/ACC guidelines indicate that surgical mitral valve repair is reasonable (Class II a) in asymptomatic patients with chronic severe primary MR with preserved LV function (LV ejection fraction [EF] 460% and LV end systolic dimension [LVESD] o40 mm) in whom the likelihood of a successful and durable repair without residual MR is more than 95% with an expected mortality rate of less than 1% when performed at a Heart Valve Center of Excellence. 9,10 In contrast, European consensus statements have relegated repair under these circumstances to Class IIIb (not favored) status. 11 The disagreement centers on differing understanding of the natural history of severe uncorrected MR. Some clinicians believe that severe MR in asymptomatic individuals is a benign con- dition that is best managed by “watchful waiting.” This recommendation is based largely on a small study of outcomes in young patients with MR and near-normal ventricular dimensions who had strictly mandated follow-up at 1 center. 12 Recent studies have exposed the excess mortality associated with severe uncorrected MR under medical management alone along with an increase in associated adverse consequences such as heart failure and atrial fibrillation. 1 Mayo Clinic College of Medicine, Rochester, Minnesota Address reprint requests to Rakesh M. Suri, MD, DPhil, Division of Cardiovascular Surgery, Mayo Clinic, 200 First St. SW, Rochester, MN 55905. E-mail: suri.rakesh@mayo.edu 1043-0679/$-see front matter ª 2014 Elsevier Inc. All rights reserved. 95 http://dx.doi.org/10.1053/j.semtcvs.2014.07.004 INVITED ARTICLE