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

Abstract

BACKGROUND 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 ePTFE 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 two techniques to correct posterior leaflet prolapse and reduce mitral regurgitation, and quantify the acute post-repair leaflet kinematics. METHODS 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 followed by induction of isolated P2 flail by transecting the two 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. RESULTS 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 to the baseline measurements. CONCLUSIONS Comparable reduction leaflet flail and regurgitation, and restoration of physiological leaflet coaptation with the two techniques indicates that under acute conditions, use of artificial neochordae or native chordal translocations have similar benefits.

Bench Models for Assessing the Mechanics of Mitral Valve Repair and Percutaneous Surgery

“…9). 27,30,38,42 In leaflet billowing, the regions of the anterior and/or posterior leaflet are observed to balloon above the mitral annular plane. Simulating this dysfunction has been achieved by selectively displacing the PMs towards the mitral annular plane.…”

“…Pulsatile flow within these systems has been generated through the use of piston pumps, 18 ventricular assist devices, 5 and pneumatic bladder-pump systems. 8,20,27 By adjusting the pump's stroke volume, frequency, and ventricular afterload; the system's ejection volume and cardiac output can be precisely controlled. While a range of hemodynamic conditions can be readily achieved, rigid LV models are most frequently operated at average human left heart hemodynamics of approximately 5 L/min cardiac output, 70 mL/beat ejection volume, 70 beats/min, and a 120 mmHg peak transmitral pressure gradient.…”

“…1a). 5,8,12,[18][19][20]22,23,[26][27][28][29][30][31][32][34][35][36][37][38][39]44,[46][47][48] These components are supplemented by systemic resistances and compliances to control cardiac output, systemic pressures, and dampen undesired flow and pressure oscillations within the rigid chambers of the system.…”

“…These models have been used to evaluate multiple repairs on a single MV, changes in leaflet mobility and coaptation, improvements in transmitral hemodynamics, and provide direct quantitative measures of tissue loading. [3][4][5]8,9,[11][12][13][14][17][18][19][20][22][23][24][26][27][28][29][30][31][32][33][34][35][36][37][38][39]41,42,44,[46][47][48] Within the limitation of each setup, these models are more risk averse, controlled, reproducible, and less expensive than clinical studies or large animal models. Understanding the advantages and limits of these models will aid the interpretation of their resulting data, inform future experimental evaluations, and further the translation of results to procedure and device development.…”

Management of Incomplete Initial Repair in the Treatment of Degenerative Mitral Insufficiency

“…Mitral valve repair was performed with selective use of one or more techniques, including posterior leaflet resection, artificial chordal implantation, chordal transfer, and edge-to-edge suturing, the details of which have been described in previous studies. [5][6][7] After the repair attempt was complete and saline testing showed a satisfactory result, annuloplasty was performed using a Carpentier-Edwards Physio I ring or a Cosgrove band (Edwards Lifesciences, Irving, CA, USA). Concomitant tricuspid annuloplasty was then performed on eight cases of the study cohort.…”