Contemporary Review in Interventional Cardiology: Mitral Annuloplasty in Secondary Mitral Regurgitation

Secondary mitral regurgitation (SMR, also known as functional mitral regurgitation or FMR) is one of the most prevalent types of valvular heart disease and occurs when the left ventricle dilates, causing papillary muscle displacement, chordal leaflet tethering, and impaired leaflet coaptation despite an otherwise structurally “normal” mitral valve. Mitral annular dilation is a common feature of SMR, and is a significant contributor to impaired leaflet coaptation. Surgical mitral annuloplasty has been used commonly since first description in 1955 and can normalize mitral annular dimensions and restore leaflet coaptation in properly selected patients. Numerous reports utilizing surgical mitral annuloplasty have established the efficacy of annular reduction in reducing SMR, but have also identified anatomic subsets in which annuloplasty is less effective. With the advent of transcatheter annuloplasty procedures, it will be imperative that members of the heart team have a clear understanding of normal and diseased mitral valve anatomy, and the risks, benefits, and technical considerations of various mitral annuloplasty procedures. This review describes the procedure of mitral annuloplasty in treating SMR, starting with describing the relevant anatomy and physiological mechanisms, followed by reviewing the evidence behind current surgical and transcatheter techniques.