Finite element analysis of annuloplasty and papillary muscle relocation on a patient-specific mitral regurgitation model

PLOS ONE, Nov 2019

Objectives Functional mitral regurgitation (FMR) is a significant complication of left ventricle (LV) dysfunction associated with poor prognosis and commonly treated by undersized ring annuloplasty. This study aimed to quantitatively simulate the treatment outcomes and mitral valve (MV) biomechanics following ring annulopalsty and papillary muscle relocation (PMR) procedures for a FMR patient. Methods We utilized a validated finite element model of the left heart for a patient with severe FMR and LV dilation from our previous study and simulated virtual ring annuloplasty procedures with various sizes of Edwards Classic and GeoForm annuloplasty rings. The model included detailed geometries of the left ventricle, mitral valve, and chordae tendineae, and incorporated age- and gender- matched nonlinear, anisotropic hyperelastic tissue material properties, and simulated chordal tethering at diastole due to LV dilation. Results Ring annuloplasty with either the Classic or GeoForm ring improved leaflet coaptation and increased the total leaflet closing force while increased posterior mitral leaflet (PML) stresses and strains. Classic rings resulted in larger coaptation forces and areas compared to GeoForm rings. The PMR procedure further improved the leaflet coaptation, decreased the PML stress and strain for both ring shapes and all sizes in this patient model. Conclusions This study demonstrated that a rigorously developed patient-specific computational model can provide useful insights into annuloplasty repair techniques for the treatment of FMR patients and could potentially serve as a tool to assist in pre-operative planning for MV repair surgical or interventional procedures.

A PDF file should load here. If you do not see its contents the file may be temporarily unavailable at the journal website or you do not have a PDF plug-in installed and enabled in your browser.

Alternatively, you can download the file locally and open with any standalone PDF reader:

https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0198331&type=printable

Finite element analysis of annuloplasty and papillary muscle relocation on a patient-specific mitral regurgitation model

June Finite element analysis of annuloplasty and papillary muscle relocation on a patient- specific mitral regurgitation model Fanwei Kong 0 1 Thuy Pham 0 1 Caitlin Martin 0 1 John Elefteriades 1 Raymond McKay 1 Charles Primiano 1 Wei Sun 0 1 0 The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University , Atlanta , Georgia , United States of America, 2 Aortic Institute of Yale-New Haven Hospital, Yale University , New Haven , Connecticut, United States of America, 3 Cardiology Department, The Hartford Hospital , Hartford, Connecticut , United States of America 1 Editor: Dalin Tang, Worcester Polytechnic Institute , UNITED STATES Functional mitral regurgitation (FMR) is a significant complication of left ventricle (LV) dysfunction associated with poor prognosis and commonly treated by undersized ring annuloplasty. This study aimed to quantitatively simulate the treatment outcomes and mitral valve (MV) biomechanics following ring annulopalsty and papillary muscle relocation (PMR) procedures for a FMR patient. We utilized a validated finite element model of the left heart for a patient with severe FMR and LV dilation from our previous study and simulated virtual ring annuloplasty procedures with various sizes of Edwards Classic and GeoForm annuloplasty rings. The model included detailed geometries of the left ventricle, mitral valve, and chordae tendineae, and incorporated age- and gender- matched nonlinear, anisotropic hyperelastic tissue material properties, and simulated chordal tethering at diastole due to LV dilation. - Data Availability Statement: All relevant data are within the paper and its Supporting Excel file. Funding: This work was supported in part by the NIH HL104080 and HL127570 grants. The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing interests: The authors have declared that no competing interests exist. Objectives Methods Results Ring annuloplasty with either the Classic or GeoForm ring improved leaflet coaptation and increased the total leaflet closing force while increased posterior mitral leaflet (PML) stresses and strains. Classic rings resulted in larger coaptation forces and areas compared to GeoForm rings. The PMR procedure further improved the leaflet coaptation, decreased the PML stress and strain for both ring shapes and all sizes in this patient model. Conclusions This study demonstrated that a rigorously developed patient-specific computational model can provide useful insights into annuloplasty repair techniques for the treatment of FMR patients and could potentially serve as a tool to assist in pre-operative planning for MV repair surgical or interventional procedures. Introduction Functional mitral regurgitation (FMR) is a significant complication of left ventricular (LV) dysfunction and is strongly associated with a poor prognosis in patients with heart failure. FMR is commonly treated by using an undersized annuloplasty ring to reduce the septallateral diameter of the annulus and improve leaflet coaptation. Annuloplasty is an effective method to correct MR with a low operative mortality rate; however, it remains controversial whether it has a substantial survival benefit over valve replacement or medical treatments for patients with severe FMR [1±3]. Significant recurrence of MR has been reported following annuloplasty [3±5]. The use of undersized annuloplasty may augment posterior leaflet tethering which contributes to persistent MR following surgical annuloplasty [ 6 ]. The three-dimensional (3D)-shaped GeoForm ring was specifically designed to aggressively reduce the septal-lateral distance while displacing the posterior annulus towards the left atrium, which may counteract the tethering forces of the chordae [ 7 ]. Papillary muscle relocation (PMR) as an adjunct procedure to downsized ring annuloplasty was developed to reduce leaflet tethering, tenting area, and coaptation depth by pulling the papillary muscle tips closer to the annulus[ 8 ]. Both techniques have demonstrated potential in effectively relieving MR and preventing recurrent MR, although cases of recurrent MR still occur [ 7,8 ]. The finite element method (FEM) has been developed and utilized as a possible tool for evaluating clinical treatment strategies and predicting treatment outcomes. While several studies have applied FEM to study the effect of annuloplasty on treating MR using various ring shapes [9±15], to our knowledge, no study has used human MR models to investigate the effect of PMR on MV biomechanics [ 16 ]. Due to the complexity of the MV apparatus, many limitations continue to undermine the accuracy of computational analysis, such as the use of simplified chordal morphology [ 9,12,13,15 ], simplified leaflet geometries [10±12,14], and assumed stress-free initial geometries. Also, such models did not account for the presence of le (...truncated)


This is a preview of a remote PDF: https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0198331&type=printable

Fanwei Kong, Thuy Pham, Caitlin Martin, John Elefteriades, Raymond McKay, Charles Primiano, Wei Sun. Finite element analysis of annuloplasty and papillary muscle relocation on a patient-specific mitral regurgitation model, PLOS ONE, 2018, Volume 13, Issue 6, DOI: 10.1371/journal.pone.0198331