MANAGEMENT OF MITRAL REGURGITATION

In 1960, mitral valve replacement was introduced as surgical treatment for mitral regurgitation (MR). Initially, this procedure was reserved for patients with New York Heart Association (NYHA) functional class III symptoms. In these patients, it was thought that the improvement in symptoms and quality of life outweighed the surgical mortality and the long-term morbidity associated with a prosthetic valve. 31 Improvements in valve design and in methods of myocardial protection coupled with development of surgical techniques for valve repair and preservation of the subvalvular apparatus have lowered surgical mortality and improved the long-term results of mitral valve surgery. Concurrent with these developments, a body of evidence has accumulated indicating the deleterious effects of left ventricular (LV) dysfunction on mortality and morbidity of patients undergoing valve replacement. Consequently the current trend is to recommend surgery earlier. Rather than wait for symptoms to progress, surgeons now commonly operate patients in NYHA functional class II, particularly if they show signs of LV dysfunction. Concerns about permanent injury to the left ventricle have prompted in some cases referral for surgery of asymptomatic patients. This article discusses the factors that may influence long-term prognosis in MR, reviews the evidence supporting earlier intervention, and provides some guidelines based, when possible, on experimental findings and at times on the author's opinion. The discussion is limited exclusively to isolated MR without stenosis or any other significant valvular lesion.