A virtual sizing tool for mitral valve annuloplasty

Functional mitral regurgitation, a backward leakage of the mitral valve, is a result of left ventricular growth and mitral annular dilatation. Its gold standard treatment is mitral annuloplasty, the surgical reduction in mitral annular area through the implantation of annuloplasty rings. Recurrent regurgitation rates may, however, be as high as 30% and more. While the degree of annular downsizing has been linked to improved long-term outcomes, too aggressive downsizing increases the risk of ring dehiscences and significantly impairs repair durability. Here, we prototype a virtual sizing tool to quantify changes in annular dimensions, surgically induced tissue strains, mitral annular stretches, and suture forces in response to mitral annuloplasty. We create a computational model of dilated cardiomyopathy onto which we virtually implant annuloplasty rings of different sizes. Our simulations confirm the common intuition that smaller rings are more invasive to the surrounding tissue, induce higher strains, and require larger suture forces than larger rings: The total suture force was 2.2 N for a 24-mm ring, 1.9 N for a 28-mm ring, and 0.8 N for a 32-mm ring. Our model predicts the highest risk of dehiscence in the septal and postero-lateral annulus where suture forces are maximal. These regions co-localize with regional peaks in myocardial strain and annular stretch. Our study illustrates the potential of realistic predictive simulations in cardiac surgery to identify areas at risk for dehiscence, guide the selection of ring size and shape, rationalize the design of smart annuloplasty rings and, ultimately, improve long-term outcomes after surgical mitral annuloplasty. Copyright © 2016 John Wiley & Sons, Ltd.

[1]  W. Stewart,et al.  Mechanism of Outflow Tract Obstruction Causing Failed Mitral Valve Repair Anterior Displacement of Leaflet Coaptation , 1993, Circulation.

[2]  Gabriel Acevedo-Bolton,et al.  Human Cardiac Function Simulator for the Optimal Design of a Novel Annuloplasty Ring with a Sub-valvular Element for Correction of Ischemic Mitral Regurgitation , 2015, Cardiovascular engineering and technology.

[3]  S. Bolling,et al.  Mechanisms of Recurrent Functional Mitral Regurgitation After Mitral Valve Repair in Nonischemic Dilated Cardiomyopathy: Importance of Distal Anterior Leaflet Tethering , 2009, Circulation.

[4]  Neil B. Ingels,et al.  Characterization of Mitral Valve Annular Dynamics in the Beating Heart , 2011, Annals of Biomedical Engineering.

[5]  A. Berrebi,et al.  The "physio-ring": an advanced concept in mitral valve annuloplasty. , 1995, The Annals of thoracic surgery.

[6]  J. Tardif,et al.  Severe aortic regurgitation immediately after mitral valve annuloplasty. , 1999, The Annals of thoracic surgery.

[7]  R A Levine,et al.  Insights from three-dimensional echocardiography into the mechanism of functional mitral regurgitation: direct in vivo demonstration of altered leaflet tethering geometry. , 1997, Circulation.

[8]  Andrew W. Siefert,et al.  In-vivo mitral annuloplasty ring transducer: implications for implantation and annular downsizing. , 2013, Journal of biomechanics.

[9]  Mechanics of the Mitral Annulus in Chronic Ischemic Cardiomyopathy , 2013, Annals of Biomedical Engineering.

[10]  Ajit P. Yoganathan,et al.  A High-Fidelity and Micro-anatomically Accurate 3D Finite Element Model for Simulations of Functional Mitral Valve , 2013, FIMH.

[11]  A. McCulloch,et al.  Stress-dependent finite growth in soft elastic tissues. , 1994, Journal of biomechanics.

[12]  R C Gorman,et al.  Dynamic three-dimensional imaging of the mitral valve and left ventricle by rapid sonomicrometry array localization. , 1996, The Journal of thoracic and cardiovascular surgery.

[13]  Chad E. Eckert,et al.  On the In Vivo Deformation of the Mitral Valve Anterior Leaflet: Effects of Annular Geometry and Referential Configuration , 2012, Annals of Biomedical Engineering.

[14]  Gerhard A. Holzapfel,et al.  Nonlinear Solid Mechanics: A Continuum Approach for Engineering Science , 2000 .

[15]  Serdar Göktepe,et al.  A multiscale model for eccentric and concentric cardiac growth through sarcomerogenesis. , 2010, Journal of theoretical biology.

[16]  A. Yoganathan,et al.  Saddle shape of the mitral annulus reduces systolic strains on the P2 segment of the posterior mitral leaflet. , 2009, The Annals of thoracic surgery.

[17]  Ellen Kuhl,et al.  The Living Heart Project: A robust and integrative simulator for human heart function. , 2014, European journal of mechanics. A, Solids.

[18]  S. Goldstein,et al.  Left ventricular shape is the primary determinant of functional mitral regurgitation in heart failure. , 1992, Journal of the American College of Cardiology.

[19]  Torsten Doenst,et al.  Sizing for mitral annuloplasty: where does science stop and voodoo begin? , 2013, The Annals of thoracic surgery.

[20]  David S. Hirsh,et al.  Real-time 3-dimensional transesophageal echocardiography in the evaluation of post-operative mitral annuloplasty ring and prosthetic valve dehiscence. , 2009, Journal of the American College of Cardiology.

[21]  J. Wong,et al.  Generating fibre orientation maps in human heart models using Poisson interpolation , 2014, Computer methods in biomechanics and biomedical engineering.

[22]  C Veyrat,et al.  Tissue Doppler, strain, and strain rate echocardiography for the assessment of left and right systolic ventricular function , 2003, Heart.

[23]  Gabriel Acevedo-Bolton,et al.  Distribution of normal human left ventricular myofiber stress at end diastole and end systole: a target for in silico design of heart failure treatments. , 2014, Journal of applied physiology.

[24]  E Kuhl,et al.  Computational modeling of growth: systemic and pulmonary hypertension in the heart , 2011, Biomechanics and modeling in mechanobiology.

[25]  A. McCulloch,et al.  Passive material properties of intact ventricular myocardium determined from a cylindrical model. , 1991, Journal of biomechanical engineering.

[26]  F. Venuta,et al.  Journal of Thoracic and Cardiovascular Surgery , 2011 .

[27]  Maria A. Holland,et al.  Growth on demand: reviewing the mechanobiology of stretched skin. , 2013, Journal of the mechanical behavior of biomedical materials.

[28]  K. Peterson,et al.  Diastolic Left Ventricular Pressure-Volume and Stress-Strain Relations in Patients with Valvular Aortic Stenosis and Left Ventricular Hypertrophy , 1978, Circulation.

[29]  Robert C Gorman,et al.  Annuloplasty ring selection for chronic ischemic mitral regurgitation: lessons from the ovine model. , 2003, The Annals of thoracic surgery.

[30]  J HOUEL,et al.  [Cardiac surgery]. , 1954, Afrique francaise chirurgicale.

[31]  R. Levine,et al.  Mechanistic insights into functional mitral regurgitation , 2002, Current cardiology reports.

[32]  Michael S Sacks,et al.  An inverse modeling approach for stress estimation in mitral valve anterior leaflet valvuloplasty for in-vivo valvular biomaterial assessment. , 2014, Journal of biomechanics.

[33]  A. Yoganathan,et al.  Impact of mitral valve geometry on hemodynamic efficacy of surgical repair in secondary mitral regurgitation. , 2014, The Journal of heart valve disease.

[34]  Peter Johansen,et al.  What forces act on a flat rigid mitral annuloplasty ring? , 2008, The Journal of heart valve disease.

[35]  Neil B. Ingels,et al.  How Do Annuloplasty Rings Affect Mitral Annular Strains in the Normal Beating Ovine Heart? , 2012, Circulation.

[36]  Andrew W. Siefert,et al.  Mitral valve annular downsizing forces: implications for annuloplasty device development. , 2014, The Journal of thoracic and cardiovascular surgery.

[37]  C. Duran,et al.  Outcome after mitral valve repair for functional ischemic mitral regurgitation. , 2002, The Journal of heart valve disease.

[38]  Roy C. P. Kerckhoffs,et al.  Computational modeling of cardiac growth in the post-natal rat with a strain-based growth law. , 2012, Journal of biomechanics.

[39]  R. Frater,et al.  Mitral ring annuloplasty: An incomplete correction of functional mitral regurgitation associated with left ventricular remodeling , 2001, Current cardiology reports.

[40]  V. Fuster,et al.  The natural history of idiopathic dilated cardiomyopathy. , 1981, The American journal of cardiology.

[41]  Ellen Kuhl,et al.  Kinematics of cardiac growth: in vivo characterization of growth tensors and strains. , 2012, Journal of the mechanical behavior of biomedical materials.

[42]  J D Humphrey,et al.  Mechanics, mechanobiology, and modeling of human abdominal aorta and aneurysms. , 2012, Journal of biomechanics.

[43]  Gideon Cohen,et al.  Recurrent mitral regurgitation after annuloplasty for functional ischemic mitral regurgitation. , 2004, The Journal of thoracic and cardiovascular surgery.

[44]  Brian P. Baillargeon,et al.  Modeling Pathologies of Diastolic and Systolic Heart Failure , 2015, Annals of Biomedical Engineering.

[45]  E. Kuhl,et al.  Mitral Valve Annuloplasty A Quantitative Clinical and Mechanical Comparison of Different Annuloplasty Devices , 2012 .

[46]  D. Adams,et al.  Mitral Valve Repair With Carpentier-McCarthy-Adams IMR ETlogix Annuloplasty Ring for Ischemic Mitral Regurgitation: Early Echocardiographic Results From a Multi-Center Study , 2006, Circulation.

[47]  Ellen Kuhl,et al.  A critical review, an in vivo parameter identification, and the effect of prestrain , 2013 .

[48]  Serdar Göktepe,et al.  Rigid, Complete Annuloplasty Rings Increase Anterior Mitral Leaflet Strains in the Normal Beating Ovine Heart , 2010, Circulation.

[49]  Jun Kwan,et al.  Geometric Differences of the Mitral Apparatus Between Ischemic and Dilated Cardiomyopathy With Significant Mitral Regurgitation: Real-Time Three-Dimensional Echocardiography Study , 2002, Circulation.