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Linear and nonlinear viscoelastic modeling of aorta and carotid pressure-area dynamics under in vivo and ex vivo conditions.
Ann Biomed Eng 2011; 39(5):1438-56AB

Abstract

A better understanding of the biomechanical properties of the arterial wall provides important insight into arterial vascular biology under normal (healthy) and pathological conditions. This insight has potential to improve tracking of disease progression and to aid in vascular graft design and implementation. In this study, we use linear and nonlinear viscoelastic models to predict biomechanical properties of the thoracic descending aorta and the carotid artery under ex vivo and in vivo conditions in ovine and human arteries. Models analyzed include a four-parameter (linear) Kelvin viscoelastic model and two five-parameter nonlinear viscoelastic models (an arctangent and a sigmoid model) that relate changes in arterial blood pressure to the vessel cross-sectional area (via estimation of vessel strain). These models were developed using the framework of Quasilinear Viscoelasticity (QLV) theory and were validated using measurements from the thoracic descending aorta and the carotid artery obtained from human and ovine arteries. In vivo measurements were obtained from 10 ovine aortas and 10 human carotid arteries. Ex vivo measurements (from both locations) were made in 11 male Merino sheep. Biomechanical properties were obtained through constrained estimation of model parameters. To further investigate the parameter estimates, we computed standard errors and confidence intervals and we used analysis of variance to compare results within and between groups. Overall, our results indicate that optimal model selection depends on the artery type. Results showed that for the thoracic descending aorta (under both experimental conditions), the best predictions were obtained with the nonlinear sigmoid model, while under healthy physiological pressure loading the carotid arteries nonlinear stiffening with increasing pressure is negligible, and consequently, the linear (Kelvin) viscoelastic model better describes the pressure-area dynamics in this vessel. Results comparing biomechanical properties show that the Kelvin and sigmoid models were able to predict the zero-pressure vessel radius; that under ex vivo conditions vessels are more rigid, and comparatively, that the carotid artery is stiffer than the thoracic descending aorta; and that the viscoelastic gain and relaxation parameters do not differ significantly between vessels or experimental conditions. In conclusion, our study demonstrates that the proposed models can predict pressure-area dynamics and that model parameters can be extracted for further interpretation of biomechanical properties.

Authors+Show Affiliations

Department of Mathematics, North Carolina State University, Box 8205, Raleigh, NC 27695-8205, USA.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.

Language

eng

PubMed ID

21203846

Citation

Valdez-Jasso, Daniela, et al. "Linear and Nonlinear Viscoelastic Modeling of Aorta and Carotid Pressure-area Dynamics Under in Vivo and Ex Vivo Conditions." Annals of Biomedical Engineering, vol. 39, no. 5, 2011, pp. 1438-56.
Valdez-Jasso D, Bia D, Zócalo Y, et al. Linear and nonlinear viscoelastic modeling of aorta and carotid pressure-area dynamics under in vivo and ex vivo conditions. Ann Biomed Eng. 2011;39(5):1438-56.
Valdez-Jasso, D., Bia, D., Zócalo, Y., Armentano, R. L., Haider, M. A., & Olufsen, M. S. (2011). Linear and nonlinear viscoelastic modeling of aorta and carotid pressure-area dynamics under in vivo and ex vivo conditions. Annals of Biomedical Engineering, 39(5), pp. 1438-56. doi:10.1007/s10439-010-0236-7.
Valdez-Jasso D, et al. Linear and Nonlinear Viscoelastic Modeling of Aorta and Carotid Pressure-area Dynamics Under in Vivo and Ex Vivo Conditions. Ann Biomed Eng. 2011;39(5):1438-56. PubMed PMID: 21203846.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Linear and nonlinear viscoelastic modeling of aorta and carotid pressure-area dynamics under in vivo and ex vivo conditions. AU - Valdez-Jasso,Daniela, AU - Bia,Daniel, AU - Zócalo,Yanina, AU - Armentano,Ricardo L, AU - Haider,Mansoor A, AU - Olufsen,Mette S, Y1 - 2011/01/04/ PY - 2010/09/24/received PY - 2010/12/21/accepted PY - 2011/1/5/entrez PY - 2011/1/5/pubmed PY - 2011/7/29/medline SP - 1438 EP - 56 JF - Annals of biomedical engineering JO - Ann Biomed Eng VL - 39 IS - 5 N2 - A better understanding of the biomechanical properties of the arterial wall provides important insight into arterial vascular biology under normal (healthy) and pathological conditions. This insight has potential to improve tracking of disease progression and to aid in vascular graft design and implementation. In this study, we use linear and nonlinear viscoelastic models to predict biomechanical properties of the thoracic descending aorta and the carotid artery under ex vivo and in vivo conditions in ovine and human arteries. Models analyzed include a four-parameter (linear) Kelvin viscoelastic model and two five-parameter nonlinear viscoelastic models (an arctangent and a sigmoid model) that relate changes in arterial blood pressure to the vessel cross-sectional area (via estimation of vessel strain). These models were developed using the framework of Quasilinear Viscoelasticity (QLV) theory and were validated using measurements from the thoracic descending aorta and the carotid artery obtained from human and ovine arteries. In vivo measurements were obtained from 10 ovine aortas and 10 human carotid arteries. Ex vivo measurements (from both locations) were made in 11 male Merino sheep. Biomechanical properties were obtained through constrained estimation of model parameters. To further investigate the parameter estimates, we computed standard errors and confidence intervals and we used analysis of variance to compare results within and between groups. Overall, our results indicate that optimal model selection depends on the artery type. Results showed that for the thoracic descending aorta (under both experimental conditions), the best predictions were obtained with the nonlinear sigmoid model, while under healthy physiological pressure loading the carotid arteries nonlinear stiffening with increasing pressure is negligible, and consequently, the linear (Kelvin) viscoelastic model better describes the pressure-area dynamics in this vessel. Results comparing biomechanical properties show that the Kelvin and sigmoid models were able to predict the zero-pressure vessel radius; that under ex vivo conditions vessels are more rigid, and comparatively, that the carotid artery is stiffer than the thoracic descending aorta; and that the viscoelastic gain and relaxation parameters do not differ significantly between vessels or experimental conditions. In conclusion, our study demonstrates that the proposed models can predict pressure-area dynamics and that model parameters can be extracted for further interpretation of biomechanical properties. SN - 1573-9686 UR - https://www.unboundmedicine.com/medline/citation/21203846/Linear_and_nonlinear_viscoelastic_modeling_of_aorta_and_carotid_pressure_area_dynamics_under_in_vivo_and_ex_vivo_conditions_ L2 - https://doi.org/10.1007/s10439-010-0236-7 DB - PRIME DP - Unbound Medicine ER -