Heterogeneous growth-induced prestrain in the heart.
Even when entirely unloaded, biological structures are not stress-free, as shown by Y.C. Fung׳s seminal opening angle experiment on arteries and the left ventricle. As a result of this prestrain, subject-specific geometries extracted from medical imaging do not represent an unloaded reference configuration necessary for mechanical analysis, even if the structure is externally unloaded. Here we propose a new computational method to create physiological residual stress fields in subject-specific left ventricular geometries using the continuum theory of fictitious configurations combined with a fixed-point iteration. We also reproduced the opening angle experiment on four swine models, to characterize the range of normal opening angle values. The proposed method generates residual stress fields which can reliably reproduce the range of opening angles between 8.7±1.8 and 16.6±13.7 as measured experimentally. We demonstrate that including the effects of prestrain reduces the left ventricular stiffness by up to 40%, thus facilitating the ventricular filling, which has a significant impact on cardiac function. This method can improve the fidelity of subject-specific models to improve our understanding of cardiac diseases and to optimize treatment options.
Department of Surgery, School of Medicine, University of California at San Francisco, USA; Institute for Biomedical Engineering, University and ETH Zürich, Switzerland. Electronic address: genet@biomed.ee.ethz.ch.
M
M
Genet
Department of Mechanical Engineering, Stanford University, CA, USA.
M K
MK
Rausch
Department of Surgery, School of Medicine, University of California at San Francisco, USA; Department of Mechanical Engineering, Michigan State University, MI, USA.
L C
LC
Lee
Department of Biomedical Engineering, Indiana University-Purdue University Indianapolis, USA.
S
S
Choy
Department of Biomedical Engineering, Indiana University-Purdue University Indianapolis, USA.
X
X
Zhao
Department of Mechanical Engineering, Michigan State University, MI, USA; Department of Cellular and Integrative Physiology, Indiana University-Purdue University Indianapolis, USA; Department of Surgery, Indiana University-Purdue University Indianapolis, USA.
G S
GS
Kassab
Institute for Biomedical Engineering, University and ETH Zürich, Switzerland.
S
S
Kozerke
Department of Surgery, School of Medicine, University of California at San Francisco, USA.
J M
JM
Guccione
Department of Mechanical Engineering, Stanford University, CA, USA; Department of Bioengineering, Stanford University, CA, USA; Department of Cardiothoracic Surgery, Stanford University, CA, USA.
E
E
Kuhl
D000818:Animals; D001158:Arteries / Q000502:physiology*; D001696:Biomechanical Phenomena; D005260:Female; D020342:Finite Element Analysis; D006352:Heart Ventricles; D006801:Humans; D008297:Male; D023421:Models, Animal; D008955:Models, Cardiovascular; D013314:Stress, Mechanical; D013552:Swine; D016276:Ventricular Function / Q000502:physiology*
Finite element method; Finite strain; Opening angle; Patient-specific modeling; Prestrain; Residual stress