Abstract 11144: Mitral Valve Leaflet Strains Are Unphysiologically Altered After Mitraclip to Repair Functional Mitral Regurgitation

Abstract

Introduction: Transcatheter edge-to-edge repair (TEER) by approximating the leaflet edges with the MitraClip system ( Fig. A ) is rapidly gaining momentum as the primary therapy for repair of functional mitral regurgitation. Though effective acutely, the unphysiological mechanics that TEER imposes on the valve can be substantial and effect durability of the repair. In this study, we used stereo digital image correlation (sDIC) to quantify the leaflet strains that TEER imposes on the mitral valve in the repair of FMR. Hypothesis: TEER imposes an unphysiological diastolic and early systolic strain on the mitral valve leaflets, which may be associated with poor long-term outcomes. Methods: MVs with intact papillary muscles (PMs) were isolated from porcine hearts and mounted within an acrylic left ventricle chamber. A speckle pattern was imprinted on the valve leaflet surface and a sDIC system with two high-speed cameras imaging at 250 fps recorded synchronized image sequences upon pressurization of the chamber to 120 mm Hg in three different configurations: baseline/healthy, FMR/tethered valve configuration, and with TEER/MitraClip. Results: FMR configuration ( Fig. A2 ) did not alter the peak systolic leaflet strains but elevated the diastolic leaflet strains. The time to peak strain was delayed as well in the FMR configuration. TEER reduced the overall systolic strains on the leaflet from the disease state, but the diastolic strains were further elevated compared to FMR condition. Sub-regional analysis depicted that the leaflet edge section where the TEER was applied was under constantly high strain throughout the cardiac cycle, without an unloading phase. Conclusions: TEER imposes a supraphysiological strain field on the mitral valve leaflet when used to repair FMR. The impact of such strains is not yet known, but may be associated with leaflet remodeling and the 2% of the procedures in which single leaflet detachment has been reported.