Heterogeneous growth-induced prestrain in the heart

• Published in: Journal of biomechanics Vol. 48; no. 10; pp. 2080 - 2089
• Main Authors: Genet, M., Rausch, M.K., Lee, L.C., Choy, S., Zhao, X., Kassab, G.S., Kozerke, S., Guccione, J.M., Kuhl, E.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Ltd 16.07.2015; Elsevier Limited; Elsevier
• Subjects: Angles (geometry); Animals; Arteries - physiology; Biomechanical Phenomena; Biomechanics; Biomedical research; Continuums; Engineering Sciences; Experiments; Female; Finite Element Analysis; Finite element method; Finite strain; Heart; Heart Ventricles; Humans; Laboratory animals; Male; Mathematical analysis; Mathematical models; Mechanical analysis; Mechanics; Medical services; Models, Animal; Models, Cardiovascular; Opening angle; Patient-specific modeling; Physical Medicine and Rehabilitation; Physiology; Prestrain; Pulmonary arteries; Residual stress; Stress, Mechanical; Swine; Ventricular Function - physiology; Finite element method; Opening angle; Patient-specific modeling; Prestrain; Finite strain; Residual stress
• ISSN: 0021-9290; 1873-2380
• DOI: 10.1016/j.jbiomech.2015.03.012

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.