Multiple MitraClips: The balancing act between pressure gradient and regurgitation.

Abstract

Transcatheter mitral valve repair with the MitraClip is used for the symptomatic management of mitral regurgitation (MR). The challenge is reducing MR while avoiding an elevated mitral valve gradient (MVG). This study assesses how multiple MitraClips used to treat MR can affect valve performance. Six porcine mitral valves were assessed using an in vitro left heart simulator in the native, moderate-to-severe MR, and severe MR cases. MR cases were tested in the no-MitraClip, 1-MitraClip, and 2-MitraClip configurations. Mitral regurgitant fraction (MRF), MVG, and effective orifice area (EOA) were quantified. Native MRF, MVG, and EOA were 14.22%, 2.59 mm Hg, and 1.64 cm², respectively. For moderate-to-severe MR, MRF, MVG, and EOA were 34.07%, 3.31 mm Hg, and 2.22 cm², respectively. Compared with the no-MitraClip case, 1 MitraClip decreased MRF to 18.57% (P < .0001) and EOA to 1.50 cm² (P = .0002). MVG remained statistically unchanged (3.44 mm Hg). Two MitraClips decreased MRF to 14.26% (P < .0001) and EOA to 1.36 cm² (P = .0001). MVG remained unchanged (3.29 mm Hg). For severe MR, MRF, MVG, and EOA were 59.79%, 4.98 mm Hg, and 2.73 cm², respectively. Compared with the no-MitraClip case, 1 MitraClip decreased MRF to 30.72% (P < .0001) and EOA to 1.82 cm² (P < .0001); MVG remained unchanged (4.03 mm Hg). MVG remained statistically unchanged. Two MitraClips decreased MRF to 23.10% (P < .0001) and EOA to 1.58 cm² (P < .0001); MVG remained statistically unchanged (3.82 mm Hg). Both MR models yielded no statistical difference between 1 and 2 MitraClips. There is limited concern regarding elevation of MVG when reducing MR using 1 or 2 MitraClips, although 2 MitraClips did not significantly continue to reduce MRF.