Abstract 14766: Acute Impact of Transapical Ventricular Reshaping Device on Dilated Left Ventricle With Functional Mitral Regurgitation in Swine Model

Abstract

Introduction: Functional mitral regurgitation (FMR) after myocardial infarction (MI) exacerbates morbidity and mortality. Correcting FMR plays a critical role in mitigating or reversing ventricular remodeling in MI patients with FMR. However, the COAPT trial demonstrated that FMR correction yields favorable results in smaller left ventricles (LVs) but not in severely dilated LVs. In this study, we evaluated the efficacy of a transapical device in MI swine model with FMR, which can perform papillary muscle approximation (PMA) and simultaneous reduction of LV volume. Methods: Yorkshire pig (n=15) were used in this study. MI was induced by percutaneous occlusion of the left circumflex artery, which caused LV dilatation and FMR by 3 months. The device was implanted through the LV apex to achieve PMA and LV reshaping until FMR was eliminated (Figure A). The immediate effects of the device implantation on the mitral valve and the LV were assessed using echocardiography and pressure-volume loops. Results: The device implantation decreased inter-papillary muscle distance from 24.5±3.8mm to 16.7±3.8mm (p<0.0001), and significantly reduced FMR. Coaptation length significantly increased from 3.4±0.7mm to 5.5±1.2mm (p<0.0001). End-diastolic volume decreased from 153±48ml to 117±33ml, a 23.5% reduction (p=0.0004). The end-systolic pressure-volume relationship and preload adjusted dP/dt max significantly increased after the device implant, indicating an improvement of LV contractility. There were no differences observed in Tau and end-diastolic pressure-volume relationship, depicting minimal acute impact on diastolic ventricular function after device implantation (Figure B and C). Conclusions: This transapical reshaping device effectively corrects FMR in very enlarged LVs, but also reduces systolic chamber wall stress by reducing the LV volume. An acute improvement in LV systolic function was observed, potentially indicating a therapeutic effect.