Abstract Body (Do not enter title and authors here): Background
Neochord repair is a common technique to mitigate mitral regurgitation (MR). Certain techniques, such as the loop technique, purposefully anchor all neochords to one papillary muscle head, generating crossed configurations. The objective was to evaluate the impact of crossing neochord on mitral valve (MV) biomechanics using ex vivo mitral valve prolapse (MVP) models.
Methods
Twenty-four healthy porcine MVs were explanted. The valves were randomly assigned to generate A2 or P2 MVP models by transecting A2 or P2 primary and secondary native chords. For each model, the valves were further randomly assigned to neochord repair by crossing the medial-lateral plane or the anterior-posterior plane. Fiber Bragg grating force sensors were mounted to measure chordal forces. Data were collected using an ex vivo heart simulator for baseline, MVP, and neochord repair in the native and the crossed configuration. Statistical analysis was performed using repeated measures analysis of variance with post-hoc correction.
Results
In the P2 MVP model, AP crossed configuration was effective in reducing MR (p=.003) compared with the native configuration (p=.004), but the medial-laterally (ML) crossed configuration was not effective in reducing MR (p=.07) compared with the native configuration (p=.05). In the A2 MVP model, anterior-posteriorly crossed configuration was associated with increased average neochordal force compared with the native configuration (0.16±0.06N vs. 0.09±0.07N, p=.05). The ML crossed configuration was also associated with increased average neochordal force compared with the native configuration (0.05±0.03N vs.0.03±0.03N, p=.03). Peak native secondary chordal forces were increased in the ML crossed configuration compared with the native configuration (0.76±0.45N vs. 0.61±0.38N, p=.05). No differences between the crossed and native configurations were observed in the P2 MVP model.
Conclusions
Differences exist in P2 MVP model hemodynamics and A2 MVP model chordal forces when neochords were crossed compared with the native configurations. These findings may provide important biomechanics insight regarding neochord implantation techniques and repair durability.