Mitral Valve Repair and Annular Motion: Is Less Really More?

Abstract

doi:10.1016/j. In North America, approximately 10,000 isolated primary mitral valve (MV) operations are performed annually, with increasing rates of MV repair. There are substantial advantages of MV repair compared with MV replacement in patients with degenerative MV disease, including lower operative mortality, improved left ventricular (LV) function, lower risk for stroke and infection, fewer complications related to anticoagulation therapy, and superior long-term survival. During the past few decades, repair techniques have evolved and improved, with different centers reporting excellent long-term results for degenerative MV disease. Current American College of Cardiology and American Heart Association guidelines for the management of patients with valvular heart disease recommend surgery for asymptomatic patients with chronic severe mitral regurgitation as long as there is high probability of MV repair with low operativemortality. The goal of achieving high rates ofMVrepair with good outcomes is dependent on surgical skills and techniques, linked to an understanding of the complexity of disease. The routine use of real-time three-dimensional (3D) transesophageal echocardiography has allowed highly detailed evaluation of the key anatomic information required for successful repair of degenerative MV disease, namely, the status of MV leaflets, chordae tendineae, and the MV annulus. There is a broad spectrum of degenerative disease causing MV prolapse, ranging from fibroelastic deficiency to advanced Barlow’s disease with marked leaflet thickening, hooding, elongated chordae, and marked annular dilation. Although MV repair has been performed since the early days of cardiac surgery, Carpentier and colleagues are credited for having developed a rational functional classification of MV lesions and techniques of repair, such as anterior and posterior leaflet resection, chordal shortening and chordal transfer, and placement of a rigid annuloplasty ring. Important advances included the introduction of artificial polytetrafluoroethylene chordae in the mid-1980s that allowed replacement instead of shortening or transfer of diseased chordae and the development of the sliding annuloplasty technique when reduction of posterior leaflet height is required to avoid postoperative dynamic LV outflow tract obstruction due to systolic anterior motion of the MV leaflets. More recently, the introduction of minimally invasive and robotic repair techniques has shown promising short-term results. It is well recognized that theMVannulus is not a fixed structure but changes its shape from a more circular and less steeply saddle-shaped configuration in diastole to a more elliptical and more steeply saddleshaped configuration in systole, which results in a significant change of the MV annular area. Of course, these dynamics are affected in diseased MVs. MV annuloplasty becomes necessary whenever the MV annulus is dilated and the normal ratio of the anterior-posterior