1
|
Thirugnanasambandam M, Canchi T, Piskin S, Karmonik C, Kung E, Menon PG, Avril S, Finol EA. Design, Development, and Temporal Evaluation of a Magnetic Resonance Imaging-Compatible In Vitro Circulation Model Using a Compliant Abdominal Aortic Aneurysm Phantom. J Biomech Eng 2021; 143:051004. [PMID: 33493273 PMCID: PMC8086180 DOI: 10.1115/1.4049894] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 01/05/2021] [Indexed: 11/08/2022]
Abstract
Biomechanical characterization of abdominal aortic aneurysms (AAAs) has become commonplace in rupture risk assessment studies. However, its translation to the clinic has been greatly limited due to the complexity associated with its tools and their implementation. The unattainability of patient-specific tissue properties leads to the use of generalized population-averaged material models in finite element analyses, which adds a degree of uncertainty to the wall mechanics quantification. In addition, computational fluid dynamics modeling of AAA typically lacks the patient-specific inflow and outflow boundary conditions that should be obtained by nonstandard of care clinical imaging. An alternative approach for analyzing AAA flow and sac volume changes is to conduct in vitro experiments in a controlled laboratory environment. In this study, we designed, built, and characterized quantitatively a benchtop flow loop using a deformable AAA silicone phantom representative of a patient-specific geometry. The impedance modules, which are essential components of the flow loop, were fine-tuned to ensure typical intraluminal pressure conditions within the AAA sac. The phantom was imaged with a magnetic resonance imaging (MRI) scanner to acquire time-resolved images of the moving wall and the velocity field inside the sac. Temporal AAA sac volume changes lead to a corresponding variation in compliance throughout the cardiac cycle. The primary outcome of this work was the design optimization of the impedance elements, the quantitative characterization of the resistive and capacitive attributes of a compliant AAA phantom, and the exemplary use of MRI for flow visualization and quantification of the deformed AAA geometry.
Collapse
Affiliation(s)
- Mirunalini Thirugnanasambandam
- University of Texas at San Antonio, UTSA/UTHSCSA Joint Graduate Program in Biomedical Engineering, San Antonio, TX 78249
| | - Tejas Canchi
- Department of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore 639798
| | - Senol Piskin
- Department of Mechanical Engineering, University of Texas at San Antonio, San Antonio, TX 78249; Department of Mechanical Engineering, Istinye University, Istanbul 34010, Turkey
| | | | - Ethan Kung
- Department of Mechanical Engineering, Clemson UniversityClemson, SC 29634
| | - Prahlad G. Menon
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15260
| | - Stephane Avril
- Ecole Nationale Supérieure des Mines, Center for Biomedical and Healthcare Engineering, St-Etienne 75006, France
| | - Ender A. Finol
- University of Texas at San Antonio, UTSA/UTHSCSA Joint Graduate Program in Biomedical Engineering, San Antonio, TX 78249; Department of Mechanical Engineering, University of Texas at San Antonio, Room EB 3.04.08 One UTSA Circle, San Antonio, TX 78249
| |
Collapse
|
2
|
Sharzehee M, Fatemifar F, Han HC. Computational simulations of the helical buckling behavior of blood vessels. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2019; 35:e3277. [PMID: 31680465 PMCID: PMC7286361 DOI: 10.1002/cnm.3277] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Revised: 08/27/2019] [Accepted: 10/17/2019] [Indexed: 06/10/2023]
Abstract
Tortuous vessels are often observed in vivo and could hinder or even disrupt blood flow to distal organs. Besides genetic and biological factors, the in vivo mechanical loading seems to play a role in the formation of tortuous vessels, but the mechanism for formation of helical vessel shape remains unclear. Accordingly, the aim of this study was to investigate the biomechanical loads that trigger the occurrence of helical buckling in blood vessels using finite element analysis. Porcine carotid arteries were modeled as thick-walled cylindrical tubes using generalized Fung and Holzapfel-Gasser-Ogden constitutive models. Physiological loadings, including axial tension, lumen pressure, and axial torque, were applied. Simulations of various geometric dimensions, different constitutive models and at various levels of axial stretch ratios, lumen pressures, and twist angles were performed to identify the mechanical factors that determine the helical stability. Our results demonstrated that axial torsion can cause wringing (twist buckling) that leads to kinking or helical coiling and even looping and winding. The specific buckling patterns depend on the combination of lumen pressure, axial torque, axial tension, and the dimensions of the vessels. This study elucidates the mechanism of how blood vessels buckle under various mechanical loads and how complex mechanical loads yield helical buckling.
Collapse
Affiliation(s)
- Mohammadali Sharzehee
- Department of Mechanical Engineering, The University of Texas at San Antonio, San Antonio, TX, USA
| | - Fatemeh Fatemifar
- Department of Mechanical Engineering, The University of Texas at San Antonio, San Antonio, TX, USA
| | - Hai-Chao Han
- Department of Mechanical Engineering, The University of Texas at San Antonio, San Antonio, TX, USA
- Biomedical Engineering Program, UTSA-UTHSCSA, San Antonio, TX
| |
Collapse
|
4
|
Peng K, Cui X, Qiao A, Mu Y. Mechanical analysis of a novel biodegradable zinc alloy stent based on a degradation model. Biomed Eng Online 2019; 18:39. [PMID: 30940146 PMCID: PMC6444843 DOI: 10.1186/s12938-019-0661-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Accepted: 03/26/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Biodegradable stents display insufficient scaffold performance due to their poor Young's Modulus. In addition, the corresponding biodegradable materials harbor weakened structures during degradation processes. Consequently, such stents have not been extensively applied in clinical therapy. In this study, the scaffold performance of a patented stent and its ability to reshape damaged vessels during degradation process were evaluated. METHODS A common stent was chosen as a control to assess the mechanical behavior of the patented stent. Finite element analysis was used to simulate stent deployment into a 40% stenotic vessel. A material corrosion model involving uniform and stress corrosion was implemented within the finite element framework to update the stress state following degradation. RESULTS The results showed that radial recoiling ratio and mass loss ratio of the patented stent is 7.19% and 3.1%, respectively, which are definitely lower than those of the common stent with the corresponding values of 22.6% and 14.1%, respectively. Moreover, the patented stent displayed stronger scaffold performance in a corrosive environment and the plaque treated with patented stents had a larger and flatter lumen. CONCLUSION Owing to its improved mechanical performance, the novel biodegradable zinc alloy stent reported here has high potential as an alternative choice in surgery.
Collapse
Affiliation(s)
- Kun Peng
- College of Life Science and Bioengineering, Beijing University of Technology, No.100, Pingleyuan, Chaoyang District, Beijing, 100124 China
| | - Xinyang Cui
- College of Life Science and Bioengineering, Beijing University of Technology, No.100, Pingleyuan, Chaoyang District, Beijing, 100124 China
| | - Aike Qiao
- College of Life Science and Bioengineering, Beijing University of Technology, No.100, Pingleyuan, Chaoyang District, Beijing, 100124 China
| | - Yongliang Mu
- Northeastern University, Shenyang, 110819 Liaoning China
| |
Collapse
|
5
|
Fatemifar F, Feldman MD, Oglesby M, Han HC. Comparison of Biomechanical Properties and Microstructure of Trabeculae Carneae, Papillary Muscles, and Myocardium in the Human Heart. J Biomech Eng 2019; 141:021007. [PMID: 30418486 PMCID: PMC6298537 DOI: 10.1115/1.4041966] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2018] [Revised: 10/28/2018] [Indexed: 12/13/2022]
Abstract
Trabeculae carneae account for a significant portion of human ventricular mass, despite being considered embryologic remnants. Recent studies have found trabeculae hypertrophy and fibrosis in hypertrophied left ventricles with various pathological conditions. The objective of this study was to investigate the passive mechanical properties and microstructural characteristics of trabeculae carneae and papillary muscles compared to the myocardium in human hearts. Uniaxial tensile tests were performed on samples of trabeculae carneae and myocardium strips, while biaxial tensile tests were performed on samples of papillary muscles and myocardium sheets. The experimental data were fitted with a Fung-type strain energy function and material coefficients were determined. The secant moduli at given diastolic stress and strain levels were determined and compared among the tissues. Following the mechanical testing, histology examinations were performed to investigate the microstructural characteristics of the tissues. Our results demonstrated that the trabeculae carneae were significantly stiffer (Secant modulus SM2 = 80.06 ± 10.04 KPa) and had higher collagen content (16.10 ± 3.80%) than the myocardium (SM2 = 55.14 ± 20.49 KPa, collagen content = 10.06 ± 4.15%) in the left ventricle. The results of this study improve our understanding of the contribution of trabeculae carneae to left ventricular compliance and will be useful for building accurate computational models of the human heart.
Collapse
Affiliation(s)
- Fatemeh Fatemifar
- Department of Mechanical Engineering,
University of Texas at San Antonio,
San Antonio, TX 78249
| | - Marc D. Feldman
- Department of Medicine,
University of Texas Health Science
Center at San Antonio,
San Antonio, TX 78229
| | - Meagan Oglesby
- Department of Medicine,
University of Texas Health Science
Center at San Antonio,
San Antonio, TX 78229
| | - Hai-Chao Han
- Department of Mechanical Engineering,
University of Texas at San Antonio,
San Antonio, TX 78249
e-mail:
| |
Collapse
|
6
|
Sharzehee M, Khalafvand SS, Han HC. Fluid-structure interaction modeling of aneurysmal arteries under steady-state and pulsatile blood flow: a stability analysis. Comput Methods Biomech Biomed Engin 2018; 21:219-231. [PMID: 29446991 PMCID: PMC5879495 DOI: 10.1080/10255842.2018.1439478] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Tortuous aneurysmal arteries are often associated with a higher risk of
rupture but the mechanism remains unclear. The goal of this study was to analyze
the buckling and post-buckling behaviors of aneurysmal arteries under pulsatile
flow. To accomplish this goal, we analyzed the buckling behavior of model
carotid and abdominal aorta with aneurysms by utilizing fluid-structure
interaction (FSI) method with realistic waveforms boundary conditions. FSI
simulations were done under steady-state and pulsatile flow for normal (1.5) and
reduced (1.3) axial stretch ratios to investigate the influence of aneurysm,
pulsatile lumen pressure and axial tension on stability. Our results indicated
that aneurysmal artery buckled at the critical buckling pressure and its
deflection nonlinearly increased with increasing lumen pressure. Buckling
elevates the peak stress (up to 118%). The maximum aneurysm wall stress
at pulsatile FSI flow was (29%) higher than under static pressure at the
peak lumen pressure of 130 mmHg. Buckling results show an increase in lumen
shear stress at the inner side of the maximum deflection. Vortex flow was
dramatically enlarged with increasing lumen pressure and artery diameter.
Aneurysmal arteries are more susceptible than normal arteries to mechanical
instability which causes high stresses in the aneurysm wall that could lead to
aneurysm rupture.
Collapse
Affiliation(s)
- Mohammadali Sharzehee
- a Department of Mechanical Engineering , The University of Texas at San Antonio , San Antonio , TX , USA
| | | | - Hai-Chao Han
- a Department of Mechanical Engineering , The University of Texas at San Antonio , San Antonio , TX , USA
| |
Collapse
|
7
|
Gama Sosa MA, De Gasperi R, Perez Garcia GS, Sosa H, Searcy C, Vargas D, Janssen PL, Perez GM, Tschiffely AE, Janssen WG, McCarron RM, Hof PR, Haghighi FG, Ahlers ST, Elder GA. Lack of chronic neuroinflammation in the absence of focal hemorrhage in a rat model of low-energy blast-induced TBI. Acta Neuropathol Commun 2017; 5:80. [PMID: 29126430 PMCID: PMC6389215 DOI: 10.1186/s40478-017-0483-z] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Accepted: 10/17/2017] [Indexed: 11/10/2022] Open
Abstract
Blast-related traumatic brain injury (TBI) has been a common cause of injury in the recent conflicts in Iraq and Afghanistan. Blast waves can damage blood vessels, neurons, and glial cells within the brain. Acutely, depending on the blast energy, blast wave duration, and number of exposures, blast waves disrupt the blood-brain barrier, triggering microglial activation and neuroinflammation. Recently, there has been much interest in the role that ongoing neuroinflammation may play in the chronic effects of TBI. Here, we investigated whether chronic neuroinflammation is present in a rat model of repetitive low-energy blast exposure. Six weeks after three 74.5-kPa blast exposures, and in the absence of hemorrhage, no significant alteration in the level of microglia activation was found. At 6 weeks after blast exposure, plasma levels of fractalkine, interleukin-1β, lipopolysaccharide-inducible CXC chemokine, macrophage inflammatory protein 1α, and vascular endothelial growth factor were decreased. However, no differences in cytokine levels were detected between blast-exposed and control rats at 40 weeks. In brain, isolated changes were seen in levels of selected cytokines at 6 weeks following blast exposure, but none of these changes was found in both hemispheres or at 40 weeks after blast exposure. Notably, one animal with a focal hemorrhagic tear showed chronic microglial activation around the lesion 16 weeks post-blast exposure. These findings suggest that focal hemorrhage can trigger chronic focal neuroinflammation following blast-induced TBI, but that in the absence of hemorrhage, chronic neuroinflammation is not a general feature of low-level blast injury.
Collapse
Affiliation(s)
- Miguel A Gama Sosa
- General Medical Research Service, James J. Peters Department of Veterans Affairs Medical Center, 130 West Kingsbridge Road, Bronx, New York, 10468, USA.
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
| | - Rita De Gasperi
- Research and Development Service, James J. Peters Department of Veterans Affairs Medical Center, Bronx, New York, USA
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Georgina S Perez Garcia
- Research and Development Service, James J. Peters Department of Veterans Affairs Medical Center, Bronx, New York, USA
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Heidi Sosa
- Research and Development Service, James J. Peters Department of Veterans Affairs Medical Center, Bronx, New York, USA
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Courtney Searcy
- Research and Development Service, James J. Peters Department of Veterans Affairs Medical Center, Bronx, New York, USA
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Danielle Vargas
- Research and Development Service, James J. Peters Department of Veterans Affairs Medical Center, Bronx, New York, USA
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Pierce L Janssen
- Research and Development Service, James J. Peters Department of Veterans Affairs Medical Center, Bronx, New York, USA
- Fishberg Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Gissel M Perez
- Research and Development Service, James J. Peters Department of Veterans Affairs Medical Center, Bronx, New York, USA
| | - Anna E Tschiffely
- Operational and Undersea Medicine Directorate, Naval Medical Research Center, Silver Spring, MD, USA
| | - William G Janssen
- Fishberg Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Richard M McCarron
- Operational and Undersea Medicine Directorate, Naval Medical Research Center, Silver Spring, MD, USA
- Department of Surgery, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Patrick R Hof
- Fishberg Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Department of Geriatrics and Palliative Care, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Fatemeh G Haghighi
- Research and Development Service, James J. Peters Department of Veterans Affairs Medical Center, Bronx, New York, USA
- Fishberg Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Stephen T Ahlers
- Operational and Undersea Medicine Directorate, Naval Medical Research Center, Silver Spring, MD, USA
| | - Gregory A Elder
- Neurology Service, James J. Peters Department of Veterans Affairs Medical Center, Bronx, New York, USA
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| |
Collapse
|
8
|
Garcia JR, Sanyal A, Fatemifar F, Mottahedi M, Han HC. Twist buckling of veins under torsional loading. J Biomech 2017; 58:123-130. [PMID: 28526174 DOI: 10.1016/j.jbiomech.2017.04.018] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Revised: 03/31/2017] [Accepted: 04/24/2017] [Indexed: 10/19/2022]
Abstract
Veins are often subjected to torsion and twisted veins can hinder and disrupt normal blood flow but their mechanical behavior under torsion is poorly understood. The objective of this study was to investigate the twist deformation and buckling behavior of veins under torsion. Twist buckling tests were performed on porcine internal jugular veins (IJVs) and human great saphenous veins (GSVs) at various axial stretch ratio and lumen pressure conditions to determine their critical buckling torques and critical buckling twist angles. The mechanical behavior under torsion was characterized using a two-fiber strain energy density function and the buckling behavior was then simulated using finite element analysis. Our results demonstrated that twist buckling occurred in all veins under excessive torque characterized by a sudden kink formation. The critical buckling torque increased significantly with increasing lumen pressure for both porcine IJV and human GSV. But lumen pressure and axial stretch had little effect on the critical twist angle. The human GSVs are stiffer than the porcine IJVs. Finite element simulations captured the buckling behavior for individual veins under simultaneous extension, inflation, and torsion with strong correlation between predicted critical buckling torques and experimental data (R2=0.96). We conclude that veins can buckle under torsion loading and the lumen pressure significantly affects the critical buckling torque. These results improve our understanding of vein twist behavior and help identify key factors associated in the formation of twisted veins.
Collapse
Affiliation(s)
- Justin R Garcia
- Department of Mechanical Engineering, University of Texas at San Antonio, USA; Biomedical Engineering Program, UTSA-UTHSCSA, USA
| | - Arnav Sanyal
- Department of Mechanical Engineering, University of Texas at San Antonio, USA
| | - Fatemeh Fatemifar
- Department of Mechanical Engineering, University of Texas at San Antonio, USA
| | - Mohammad Mottahedi
- Department of Mechanical Engineering, University of Texas at San Antonio, USA
| | - Hai-Chao Han
- Department of Mechanical Engineering, University of Texas at San Antonio, USA; Biomedical Engineering Program, UTSA-UTHSCSA, USA; Institute of Mechanobiology & Medical Engineering, Shanghai Jiaotong University, China.
| |
Collapse
|