Abstract 13904: Ex vivo Biomechanical Analysis of Elastic Artificial Chordae Implantation for Beating-heart Transapical Mitral Valve Repair

Abstract

Introduction: Beating-heart transapical mitral valve repair represents a significant advancement in the minimally invasive treatment of mitral regurgitation. However, current techniques require increased artificial chordae length and altered anchoring position, which may increase the stresses on the suture. We hypothesized that artificial chordae manufactured with increased elasticity will dampen sharp increases in force, thus theoretically increasing durability. Methods: Porcine mitral valves (n=3) were mounted in a heart simulator and isolated mitral regurgitation was induced by cutting posterior primary chordae. Each valve was first repaired with standard CV-5 polytetrafluoroethylene (PTFE) suture affixed to a 3D-printed anchor with an embedded high-resolution Fiber Bragg Grating sensor to measure forces (Fig A). The repair was then repeated with an elastic suture manufactured using a biocompatible silicone and designed with a cross-sectional area of 0.56mm 2 , a geometry calculated to result in a desired 10-15% strain at relevant forces (Fig B). Results: Both materials allowed for successful repairs: mitral leakage volume was reduced from 28.29±4.83ml to 1.26±0.99ml ( p =0.009) with PTFE suture, and to 1.78±0.88ml ( p =0.008) with the elastic suture, with no significant difference between the repairs. Normalized force tracings (Fig C, standard deviation is shaded) revealed that the elastic suture resulted in a significantly lower peak systolic force when compared to PTFE suture (0.23±0.04N vs 0.32±0.03N, p =0.007). Conclusions: Artificial chordae with increased elasticity compared to traditional PTFE suture can dampen sharp peaks in force, thus offering a promising advancement in improving transapical repair durability. This proposal has the potential to apply to open-heart artificial chordae implantation as well. Future work to optimize suture material and manufacturability will help translate this development into clinical use.