Comparison of Artificial Neochordae and Native Chordal Transfer in the Repair of a Flail Posterior Mitral Leaflet: An Experimental Study

Abstract

Surgical reconstruction of a flail posterior leaflet is a routine mitral valve repair, the techniques for which have evolved from leaflet resection to leaflet preservation. Artificial expanded polytetrafluoroethylene neochordae are frequently used to stabilize the flail leaflet and seldom, translocation of the native secondary chordae of the valve to the leaflet free edge is used. In this study, we sought to investigate the efficacy of the 2 techniques to correct posterior leaflet prolapse and reduce mitral regurgitation, and quantify the acute post repair leaflet kinematics. Adult porcine mitral valves (n =7) were studied in a pulsatile left heart experimental model in which isolated P2 flail was mimicked by marginal chordal transection. Baseline conditions were established in each valve under normal conditions (control) and were followed by induction of isolated P2 flail by transecting the 2 marginal chordae on the posterior leaflet free edge (disease). The flail posterior leaflet was reconstructed using artificial neochordae (repair 1) and then native chordal translocation (repair 2). Reduction in leaflet flail, changes in mitral regurgitation fraction, leaflet coaptation length, and posterior leaflet mobility were measured using B-mode echocardiography or color Doppler. At baseline, all the valves were competent with no mitral regurgitation. After transection of the marginal chordae on the posterior leaflet, isolated P2 flail was evident with 13.7% ± 13% regurgitation. Reconstruction with artificial neochordae eliminated leaflet flail and reduced mitral regurgitation to 3.2% ± 2.8%, and with chordal translocation leaflet flail was corrected and mitral regurgitation was measured at 2.3% ± 2.6%. Using either repair techniques, leaflet coaptation and mobility of the repaired leaflets were adequate and comparable with the baseline measurements. Comparable reduction leaflet flail and regurgitation, and restoration of physiologic leaflet coaptation with the 2 techniques indicate that under acute conditions, use of artificial neochordae or native chordal translocations have similar benefits.