It is also a key part of the procedure. Patients who benefit the most from MitraClip are those with degenerative MR or functional MR being other etiologies a contraindication for percutaneous treatment: rheumatic MR (type IIIa), endocarditic valve diseases or perforated mitral leaflets (endocarditic or cleft).

Along with etiology, careful evaluation of the anatomy of the MV will define suitability for the procedure. Assessment of anatomical specific measurements should be performed with TEE. Mainly, all those anatomic variations or abnormalities that may limit the possibility of leaflet grasping and clipping should be evaluated. As mentioned before, presence of significant stenosis is considered a contraindication. MV area should be assessed using the pressure half time method or by direct planimetry of the MV area by 2D or 3D echocardiography (Fig. 18.1). 2D TEE allows accurate evaluation of MV anatomy; however 3D TEE is helpful, especially for the assessment of the leaflet segment involved in cases of MV prolapse. In the case of functional MR, coaptation depth (Fig. 18.2) and length (Fig. 18.3) is normally measured in a mid esophagus 4 chamber plane and in the case of type II MR, A2 and P2 leaflet gap (Fig. 18.4) is best evaluated either in the 4 chambers view or in the long axis view (120°) while flail/prolapsed width should be assess in a transgastric short axis view or intercommissural view. Degree of thickness and calcification of mitral leaflets should be assessed as well. Another important issue to assess is the dimension of the left atrium (LA) and interatrial septal morphology, with presence of patent foramen oval depicted. Atrial septal puncture as will be discuss later, should be performed in the superior and posterior aspect of the interatrial septum (never through a patent foramen oval) and from the puncture point to the mitral coaptation point a minimum distance of 3.5–4 cm is needed (Fig. 18.5). This distance is the minimum distance necessary for movement and turning of the system once in the LA to reach the MV. In Table 18.2 accepted anatomic measurements and characteristics for MitraClip procedure are summarized. Of note, accepted echocardiographic criteria are based on those used in the clinical trial EVEREST I and II where patients with LV ejection fraction below 25 % or LV end systolic dimension >55 mm were not included [8, 9].

The MitraClip^TM is a polyester fabric-covered cobalt-chromium device with two arms which can be opened and closed with a steerable-guiding mechanism (Fig. 18.6). The system is composed by a catheter guide, a deliverable system and the clip itself. On the inner portion of the clip, the “grippers” secure the leaflets when the clip is closed [10]. It can be easily seen on TEE which allows along with fluoroscopy and step-by-step guidance of the implantation [3]. The procedure is performed under general anesthesia using an antegrade approach and it can be divided in 4 different steps: transseptal puncture, system advance to the MV, system alignment in the MR regurgitant orifice and MitraClip delivery.