Abstract 16974: Experimental Insights Into Transapical Neochordplasty: A Quantitative Examination of Neochord Placement Using an Ex Vivo Left Heart Simulator

Introduction: Neochordoplasty is an important repair technique, though the optimal anchoring position is unknown. While typically anchored at papillary muscles, new percutaneous devices anchor the chordae at or near the ventricular apex, which we hypothesize will result in significantly higher forces on the chordae and neochord. Methods: Porcine mitral valves were dissected (n=3) and mounted in a custom 3D printed left heart simulator generating physiological pressure and flow. Hemodynamic and echocardiographic data were collected, and chordal forces were measured using Fiber Bragg Grating (FBG) strain gauge sensors. Isolated MR was induced by cutting P2 primary chordae resulting in prolapse. Regurgitant valves were then repaired with a PTFE neochord with transapical fixation, followed by papillary fixation for comparison. In both cases, the neochord was anchored to a customized force-sensing post positioned to mimic in vivo placement ( Fig. A ). Results: Hemodynamic and echocardiographic data confirmed that both techniques resulted in elimination of MR in all valves and restoration of physiologic hemodynamics. Peak forces on the chordae and neochord were lower for papillary than the transapical fixation (p=0.04). Force tracings were compiled for each class of chordae at baseline, after prolapse, and after both repair techniques ( Fig. B ). The maximum dF/dt for the neochord suture was 30.6 N/s with the papillary fixation and 51.7 N/s with the transapical fixation. These may translate into increased stress on the mitral valve apparatus. Conclusions: Transapical fixation results in higher peak forces on the chordae and noechord suture as well as an increased rate of loading on the neochord when compared to the papillary muscle fixation and may influence repair durability.