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Percutaneous Mitral Edge-to-Edge Repair
Acknowledgments
The authors gratefully acknowledge Julia Grapsa, MD, PhD; Ilias D. Koutsogeorgis, MD; Petros Nihoyannopoulos, MD; and Ferande Peters, MD, who were the authors of this chapter in the previous edition.
The percutaneous mitral edge-to-edge repair is based on the principle of surgical edge-to-edge repair, also known as the Alfieri technique, introduced in 1991 by the Italian surgeon Ottavio Alfieri, who successfully treated a patient with anterior leaflet prolapse. , Using a stitch, he approximated the edges of the middle portions of the anterior and posterior leaflets to create a double-orifice mitral valve (MV). The surgical group subsequently reported a series of 260 patients, of whom 80% underwent the Alfieri technique and had additional mitral annuloplasty, which was associated with reduced rate of reoperation within a follow-up period of 5 years.
The initial percutaneous edge-to-edge repair system is referred to as the MitraClip (Abbott). Since then at least one additional system has been developed, namely the PASCAL system (Edwards LifeScience). The mitral leaflet–grasping device in both systems may be generically referred to as a “mitral clip.” In this chapter, percutaneous edge-to-edge repair is described for the MitraClip, but similar principles apply to the PASCAL system.
The percutaneously implanted MitraClip has been the most studied device for the transcatheter treatment of mitral regurgitation (MR). The Endovascular Valve Edge-to-Edge Repair Study I (EVEREST I) demonstrated efficacy, safety, and clear hemodynamic improvement in patients with moderate to severe and severe MR. In the EVEREST II trial, , , the percutaneous approach was safer than surgery (30-day rate of major adverse cardiac events, 15% vs 48%; P < .001). Although patients treated with the MitraClip more commonly required surgery to treat residual MR by the first year of follow-up, a limited number of surgeries were needed, and there was no difference in the prevalence of moderate to severe and severe MR or mortality at 4 years. Other studies confirmed the efficacy of the MitraClip in primary (degenerative) MR. More recently, the MitraClip device has been demonstrated to show benefit in patients with secondary (functional) MR. ,
Indications
Patient selection criteria for the percutaneous mitral edge-to-edge repair procedure is based entirely on echocardiography. Transthoracic echocardiography (TTE) is an initial appropriate screening tool for presence and severity of MR. Determination of suitability for edge-to-edge repair is determined based on morphologic features of MV visualized on transesophageal echocardiography (TEE). As the procedural experience has increased, the suitability criteria have expanded ( Table 166.1 ) into optimal, challenging, and unsuitable morphologies for both primary and secondary MR ( Fig. 166.1 ).
TABLE 166.1
Suitability Criteria for the MitraClip Procedure That Encompasses Both Primary and Secondary Mitral Regurgitation
Adapted from Nyman CB, et al: Transcatheter mitral valve repair using the edge-to-edge clip, J Am Soc Echocardiogr 31:434–453, 2018.
| Optimal Morphology | Challenging Morphology | Unsuitable Morphology |
|---|---|---|
| Central A2 or P2 pathology | Peripheral A1/P1 or A3/P3 pathology | Cleft or perforation |
| No calcification of leaflets | Calcification present but not in grasping zone | Calcification in grasping zone |
| MVA >4 cm 2 | MVA 3–4 cm 2 | MVA <3 cm 2 or MG >5 mm Hg |
| Posterior leaflet >10 mm | Posterior leaflet 7–10 mm | Posterior leaflet <7 mm |
| Tenting height <11 mm; coaptation reserve >2 mm | Tenting height ≥11 mm | |
| Normal leaflets and mobility | Carpentier IIIB (restricted motion in diastole) | Carpentier IIIA (restricted motion in systole and diastole) |
| Flail gap <10 mm; flail width <15 mm | Flail width >15 mm (with sufficient valve area to tolerate multiple clips) | Multiple segments, Barlow’s valve |
MVA , Mitral valve area; MG , mean gradient.
Video 166.1. Morphologic criteria for the MitraClip device using two-dimensional transesophageal echocardiography. A, Optimal: isolated P2 flail with a flail gap smaller than 10 mm. B, Optimal: reduced coaptation with adequate coaptation length and depth. C, Unsuitable: anterior leaflet calcification at the grasping zone (arrow) . D, Unsuitable: multiple segments with severe billowing (arrow) . (Also see Fig. 166.1).
Transesophageal Echocardiography
Multiplane TEE is the gold-standard modality for preoperative assessment as well as intraprocedural guidance for percutaneous mitral edge-to-edge repair insertion. To perform a comprehensive examination of the MV, it is essential to understand how transesophageal probe maneuvers change the imaging plane with respect to the MV.
Two-dimensional (2D) TEE has long been used to visualize the scallops of the MV. In the standard midesophageal four-chamber view (typically at a transducer angle of 0 degrees), A1, A2, P1, and P2 scallops are best visualized. From this position, flexion and withdrawal of the transducer tip allow visualization of the aortic root and anterolateral portions of the mitral leaflets at 120 degrees (A2 and P2). Similarly, retroflexion and advancement of the transducer tip allow visualization of the posteromedial portions of the leaflets (A3 and P3). The midesophageal plane at an angle between 45 and 90 degrees (intercommissural, also referred to as bicommissural, view) provides the opportunity for mitral leaflets to be examined with a plane parallel to the mitral orifice and to confirm MV pathology. Through the major axis of the valve orifice, P3, A2, and P1 may be evaluated on the TEE image from left to right. Subsequently, by manual rotation of the probe in a clockwise direction, the entire anterior leaflet can be visualized (A1, A2, and A3). Counterclockwise probe rotation provides visualization of the entire posterior leaflet (P1, P2, and P3). Other imaging planes and transducer positions, such as the transgastric short-axis view, may be used for additional imaging and to assist with the assessment of the MV.
Three-dimensional (3D) TEE is superior to 2D TEE in visualizing the entire anatomy of the MV in real time, the “surgeon’s view” with the aortic root at the 12 o’clock position, establishing the anterior landmark ( Fig. 166.2 ). From this view, the different scallops can be seen in their entirety along with surrounding structures and anatomic landmarks. Adding color to the 3D TEE view can help localize and quantify severity of MR, particularly multiple jets. Although 2D TEE is adequate for vena contracta, direct measurement of vena contracta area using 3D TEE demonstrates that jets are not spherical ( Fig. 166.3 ), and geometric assumptions may be challenging with multiple jets. The assessment of the severity of MR follows the current guidelines for MV evaluation and encompasses and both 2D and 3D quantitative methods.
Video 166.2. Three-dimensional transesophageal echocardiography mitral valve en face (“surgeon’s view”) from the left atrium, with appropriate anatomic landmarks. This patient has severe prolapse and flail of the P2 scallop (arrow) . (Also see Fig. 166.2).
Procedure
The percutaneous mitral edge-to-edge repair procedure is divided into seven important steps.
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