The MitraClip (Abbott Laboratories, Chicago, IL) device offers a novel, percutaneous, transvenous, transcatheter approach for patients suffering from severe mitral regurgitation, despite maximal medical therapy, in whom surgery is not an option. This chapter serves to describe mitral valve anatomy in the context of regurgitant pathology, provide a detailed description of the MitraClip procedure along with practical “pearls” to optimize deployment, and finally outline the current evidence base for MitraClip through a brief review of published literature.
The mitral valve apparatus is an elegantly complex structure that is comprised of the mitral valve leaflets, annulus, annular attachment at the atrioventricular junction, chordae tendineae, and the papillary muscles, all of which work synchronously throughout the cardiac cycle to deliver blood to the left ventricle.
The valve itself is composed of the aortic and mural leaflets, more often clinically referred to as the anterior and posterior leaflet, respectively.1,2 The anterior leaflet of the mitral valve is broader than the posterior leaflet and comprises one-third of the annular circumference. This semicircular anterior leaflet shares a fibrous continuity with the left and noncoronary cusps of the aortic valve and between the aortic cusps adjacent to the membranous septum. This region of continuity is referred to as the intervalvular fibrosa or aortic-mitral curtain. The motion of the leaflet defines an important boundary between the inflow (during diastole) and outflow (during systole) tracts of the left ventricle. In contrast to the anterior leaflet, the posterior leaflet is narrower and extends two-thirds around the left atrioventricular junction within the inlet portion of the ventricle. The posterior leaflet is commonly described as having 2 clefts that separate the leaflet into 3 scallops along the free edge. The Carpentier nomenclature describes the most lateral scallop as P1, adjacent to the anterolateral commissure; the central scallop as P2; and the most medial as P3, adjacent to the posteromedial commissure.1,2 The anterior leaflet is divided into 3 regions, named A1, A2, and A3, which correspond to the opposing scallops of the posterior leaflet (Fig. 46-1). Often, the free edge of the anterior leaflet is continuous and without indentation, making the distinction between different regions of the anterior leaflet somewhat challenging.
MitraClip Implantation Pearl
The primary purpose of the MitraClip procedure is to perform a percutaneous edge-to-edge repair and effectively create a double mitral orifice, based on the original "Alfieri stitch" surgical approach.3 Accordingly, due to the central location within the valvular complex, A2 and P2 pathology generally provides the ideal anatomy for procedural success. Commissural regurgitant jets pose a technical challenge, due to difficulty delivering the clip and grasping tissue at the ends of the free edge of each leaflet.
The mitral annulus gives a point ...