The neochord mitral valve repair procedure: Numerical simulation of different neochords tensioning protocols

Transapical off-pump mitral valve repair with neochord implantation is an established technique for minimally-invasive intervention on mitral valve prolapse/flail. The procedure involves the positioning of artificial chords, whose length/tension is adjusted intraoperatively, adopting different methods based on the experience of the surgeon. This unsystematic approach occasionally leads to complications such as leaflet rupture and excessive/insufficient load on the neochords. In this study, finite element models of a generalized prolapsing mitral valve are used to verify the effect of two alternative tensioning approaches (AT – All together and 1-by-1 – one by one sequences) on the coaptation area and valve biomechanics, comparing results with a corresponding healthy configuration. The total force of about 1 N is exerted by the chords in both strategies, but the maximum stress and coaptation area are closer to those of the healthy configuration in the 1-by-1 sequence. However, the analysis also provides an explanation for the chords unloading in the 1-by-1 strategy observed in the clinical practice, and suggests an optimum tensioning methodology for NeoChord procedures. The study also reveals the potential power of the implemented numerical approach to serve as a tool for procedural planning, supporting the identification of the most suitable ventricular access site and the most effective stitching points for the artificial chords.