Impact of Anchor Location on Mitral Neochordae Forces: An In Vitro Study.

Abstract

This study examined changes in force distribution between the neochordae corresponding to different ventricular anchor locations. Seven porcine mitral valves were mounted in a left heart simulator. Neochordae (expanded polytetrafluoroethylene) originated from either a simulated left ventricular apex, papillary muscle base, or papillary muscle tip location. The neochordae were attached at three sites along the P₂ leaflet segment: P_2Lateral; P_2Center, and P_2Medial. Mitral regurgitation was induced by cutting posterior leaflet P₂ marginal chordae. The forces on each neochord required to restore normal mitral valve coaptation were quantified for different ventricular anchoring origins and leaflet insertion sites. The results showed that under both normotensive and hypertensive conditions, the force exerted was much higher at P_2Center than either P_2Lateral or P_2Medial, independent of ventricular anchor location. Also, forces on both P_2Lateral and P_2Medial were not statistically different. Artificial neochordae treatment for all anchoring locations was effective in correcting induced mitral regurgitation. The P₂ central neochordae had a significantly higher force than both lateral neochords under all conditions.