Computer simulations of transapical mitral valve repair with neochordae implantation: Clinical implications

• Type of Material: Article
• Authors: Andrés Caballero, Georgia Institute of Technology; Raymond McKay, Hartford Hospital; Wei Sun, Emory University
• Language: English
• Date: 2020-09-01
• Publisher: Elsevier
• Publication Version: Final Published Version
• Copyright Statement: © 2020 The Authors
• License: Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1016/j.xjon.2020.05.010
• Title of Journal or Parent Work: JTCVS Open
• Volume: 3
• Start Page: 27
• End Page: 44
• Keywords: MR, mitral regurgitation; ePTFE, expanded polytetrafluoroethylene; AML, anterior mitral leaflet; AL-NC, antero-lateral neochordae; NC, neochordae; PM, papillary muscle; transapical neochord; beating heart mitral valve repair; PML, posterior mitral leaflet; PL-NC, postero-lateral neochordae; FSI, fluid-structure interaction; AV, aortic valve; primary mitral regurgitation; ePTFE suture; fluid-structure interaction FSI; LV, left ventricle; MV, mitral valve
• Research Categories: Engineering, Biomedical

Abstract

Objectives: Transapical beating heart neochordae implantation is an innovative mitral valve repair technique that has demonstrated promising clinical results in patients with primary mitral regurgitation. However, as clinical experience continues to increase, neochordae implantation criteria have not been fully standardized. The aim of this study was to investigate the biomechanical effects of selecting an antero-lateral apical access site compared with a postero-lateral site, and suboptimal neochordae length compared with optimal suture length, on restoring physiologic left heart dynamics. Methods: Transapical neochordae implantation using 3 and 4 sutures was computer simulated under 3 posterior mitral leaflet prolapse conditions: isolated P2, multiscallop P2/P3 and multiscallop P2/P1. Physiologic, pre- and postrepair left heart dynamics were evaluated using a fluid-structure interaction modeling framework. Results: Despite the absence of residual mitral regurgitation in all postrepair models with optimal neochordae length, selecting an antero-lateral apical entry site for the treatment of P2/P3 prolapse generated a significant increase (>80%) in neochordae tension and P2 peak stress, with respect to a postero-lateral entry site. During isolated P2 prolapse repair, although neochordae overtension by 5% led to minimal hemodynamic changes in the regurgitant volume compared with using an optimal suture length, a significant increase in systolic and diastolic neochordae tension (>300%) and posterior leaflet average stress (70%-460%) was quantified. On the other hand, neochordae undertension by 5% led to worsening of regurgitation severity. Conclusions: This parametric computer study represents a further step toward an improved understanding of the biomechanical outcomes of transapical neochordae technologies.