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)