Chronic mitral regurgitation and aortic regurgitation: have indications for surgery changed?

The timing of surgery in patients with mitral regurgitation (MR) and aortic regurgitation (AR) continues to elicit uncertainty and considerable controversy. Some patients will incur myocardial structural changes, pulmonary hypertension, or arrhythmias before they manifest symptoms, with the risk that these adverse endpoints will not be reversible after valve repair or replacement. Imaging to assess valve morphology, severity of regurgitation, and left ventricular (LV) volume and function is firmly established, and the guidelines of the American College of Cardiology/American Heart Association and the European Society of Cardiology support this approach. However, with improvement in surgical technique and outcomes, there is momentum toward earlier intervention before patients reach class I indications of symptoms or LV systolic dysfunction, particularly in patients with degenerative MR who are candidates for mitral repair. In expert centers, mitral valve repair is achieved at low risk and with excellent long-term durability of repair, returning patients to a lifespan equivalent to that of the normal population. In AR, decision making is more complex because patients almost invariably require valve replacement. Prospective clinical trials are needed to provide the evidence base for more objective decisions regarding timing of surgery. Biomarkers and new methods to assess interstitial fibrosis and regional myocardial function have also evolved for clinical investigation and hold the promise of enhanced determination of those in whom early surgical intervention is warranted.