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Curcio N, Rosato A, Mazzaccaro D, Nano G, Conti M, Matrone G. 3D patient-specific modeling and structural finite element analysis of atherosclerotic carotid artery based on computed tomography angiography. Sci Rep 2023; 13:19911. [PMID: 37964071 PMCID: PMC10645924 DOI: 10.1038/s41598-023-46949-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Accepted: 11/07/2023] [Indexed: 11/16/2023] Open
Abstract
The assessment of carotid plaque vulnerability is a relevant clinical information that can help prevent adverse cerebrovascular events. To this aim, in this study, we propose a patient-specific computational workflow to quantify the stress distribution in an atherosclerotic carotid artery, by means of geometric modeling and structural simulation of the plaque and vessel wall. Ten patients were involved in our study. Starting with segmentation of the lumen, calcific and lipid plaque components from computed tomography angiography images, the fibrous component and the vessel wall were semi-automatically reconstructed with an ad-hoc procedure. Finite element analyses were performed using local pressure values derived from ultrasound imaging. Simulation outputs were analyzed to assess how mechanical factors influence the stresses within the atherosclerotic wall. The developed reconstruction method was first evaluated by comparing the results obtained using the automatically generated fibrous component model and the one derived from image segmentation. The high-stress regions in the carotid artery wall around plaques suggest areas of possible rupture. In mostly lipidic and heterogeneous plaques, the highest stresses are localized at the interface between the lipidic components and the lumen, in the fibrous cap.
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Affiliation(s)
- Nicoletta Curcio
- Department of Electrical, Computer and Biomedical Engineering, University of Pavia, Pavia, Italy
| | - Antonio Rosato
- 3D and Computer Simulation Laboratory, IRCCS Policlinico San Donato, San Donato Milanese, Italy
| | - Daniela Mazzaccaro
- Operative Unit of Vascular Surgery, IRCCS Policlinico San Donato, San Donato Milanese, Italy
| | - Giovanni Nano
- Operative Unit of Vascular Surgery, IRCCS Policlinico San Donato, San Donato Milanese, Italy
- Department of Biomedical Sciences for Health, University of Milan, Milan, Italy
| | - Michele Conti
- Department of Civil Engineering and Architecture, University of Pavia, Pavia, Italy
| | - Giulia Matrone
- Department of Electrical, Computer and Biomedical Engineering, University of Pavia, Pavia, Italy.
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Mendieta JB, Fontanarosa D, Wang J, Paritala PK, Muller J, Lloyd T, Li Z. MRI-based mechanical analysis of carotid atherosclerotic plaque using a material-property-mapping approach: A material-property-mapping method for plaque stress analysis. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2023; 231:107417. [PMID: 36827823 DOI: 10.1016/j.cmpb.2023.107417] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 01/23/2023] [Accepted: 02/07/2023] [Indexed: 06/18/2023]
Abstract
BACKGROUND AND OBJECTIVE Atherosclerosis is a major underlying cause of cardiovascular conditions. In order to understand the biomechanics involved in the generation and rupture of atherosclerotic plaques, numerical analysis methods have been widely used. However, several factors limit the practical use of this information in a clinical setting. One of the key challenges in finite element analysis (FEA) is the reconstruction of the structure and the generation of a mesh. The complexity of the shapes associated with carotid plaques, including multiple components, makes the generation of meshes for biomechanical computation a difficult and in some cases, an impossible task. To address these challenges, in this study, we propose a novel material-property-mapping method for carotid atherosclerotic plaque stress analysis that aims to simplify the process. METHODS The different carotid plaque components were identified and segmented using magnetic resonance imaging (MRI). For the mapping method, this information was used in conjunction with an in-house code, which provided the coordinates for each pixel/voxel and tissue type within a predetermined region of interest. These coordinates were utilized to assign specific material properties to each element in the volume mesh which provides a region of transition. The proposed method was subsequently compared to the traditional method, which involves creating a composed mesh for the arterial wall and plaque components, based on its location and size. RESULTS The comparison between the proposed material-property-mapping method and the traditional method was performed in 2D, 3D structural-only, and fluid-structure interaction (FSI) simulations in terms of stress, wall shear stress (WSS), time-averaged WSS (TAWSS), and oscillatory shear index (OSI). The stress contours from both methods were found to be similar, although the proposed method tended to produce lower local maximum stress values. The WSS contours were also in agreement between the two methods. The velocity contours generated by the proposed method were verified against phase-contrast magnetic resonance imaging (MRI) measurements, for a higher level of confidence. CONCLUSION This study shows that a material-property-mapping method can effectively be used for analyzing the biomechanics of carotid plaques in a patient-specific manner. This approach has the potential to streamline the process of creating volume meshes for complex biological structures, such as carotid plaques, and to provide a more efficient and less labor-intensive method.
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Affiliation(s)
- Jessica Benitez Mendieta
- School of Mechanical, Medical and Process Engineering, Queensland University of Technology, Brisbane 4000, Australia
| | - Davide Fontanarosa
- School of Clinical Sciences, Queensland University of Technology, Brisbane 4000, Australia
| | - Jiaqiu Wang
- School of Mechanical, Medical and Process Engineering, Queensland University of Technology, Brisbane 4000, Australia
| | - Phani Kumari Paritala
- School of Mechanical, Medical and Process Engineering, Queensland University of Technology, Brisbane 4000, Australia
| | - Juanita Muller
- Department of Vascular Surgery, Princess Alexandra Hospital, Brisbane 4102, Australia
| | - Thomas Lloyd
- Department of Radiology, Princess Alexandra Hospital, Brisbane 4102, Australia
| | - Zhiyong Li
- School of Mechanical, Medical and Process Engineering, Queensland University of Technology, Brisbane 4000, Australia; Faculty of Sports Science, Ningbo University, Ningbo 315211, China.
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Wang S, Yao W, Zhu X, Wang J, Lu L, Zhu N, Lan T, Kuang Y, Zhu W, Liu R, Huang L. Exploring the mechanism of the antithrombotic effects of Pueraria lobata and Pueraria lobata var. thomsonii based on network pharmacology. JOURNAL OF ETHNOPHARMACOLOGY 2023; 300:115701. [PMID: 36089177 DOI: 10.1016/j.jep.2022.115701] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 07/26/2022] [Accepted: 09/02/2022] [Indexed: 06/15/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Pueraria lobata (Willd.) Ohwi and Pueraria lobata var. thomsonii (Benth.) Maesen are nutritious medicine food homology plants that are widely used in the food and health products industry and are excellent natural materials for the development of new health foods, with great potential for domestic and foreign markets. Clinically, P. lobata and P. thomsonii are used to treat coronary heart disease, atherosclerosis, cerebral infarction and other cardiovascular diseases, and antithrombotic actions may be their core effect in the treatment of thrombotic diseases. However, the underlying mechanisms of the antithrombotic properties of P. lobata and P. thomsonii have not been clarified. METHODS First, P. lobata and P. thomsonii were identified by high-performance liquid chromatography (HPLC). An arteriovenous bypass thrombosis rat model was established. Thrombus dry‒wet weight, platelet accumulation rate and the four coagulation indices, including activated partial thromboplastin time (APTT), prothrombin time (PT), thrombin time (TT) and fibrinogen (FIB), were detected in plasma to manifest the P. lobata and P. thomsonii antithrombotic function. Network pharmacology and molecular docking methods were used to obtain key targets and verify reliability. David 6.8 was used for GO and KEGG analyses to explore pathways and potential targets for P. lobata and P. thomsonii antithrombotic functions. Prostaglandin I2 (PGI2), thromboxane A2 (TXA2), cyclooxygenase 2 (COX-2), myeloperoxidase (MPO) and endothelial nitric oxide synthase (eNOS) were tested by enzyme-linked immunosorbent assay (ELISA). RESULTS The results indicated that P. lobata and P. thomsonii can reduce thrombus dry‒wet weight and platelet accumulation in rats and inhibit TT, APTT, FIB, and PT. A comprehensive network pharmacology approach successfully identified 9 active ingredients in P. lobata and P. thomsonii. The main active ingredients include polyphenols, amino acids and flavonoids. A total of 15 antithrombotic function targets were obtained, including 3 key targets (PTGS2, NOS3, MPO). Pathway analysis showed 10 significant related pathways and 29 biological processes. P. lobata and P. thomsonii inhibited platelet aggregation by upregulating PGI2 and downregulating TXA2, inhibited PTGS2 to reduce inflammation, and increased the level of eNOS to promote vasodilation. In addition, P. lobata and P. thomsonii alleviated oxidative stress by increasing SOD levels and significantly decreasing MDA contents. CONCLUSION The results of the study further clarify the antithrombotic mechanism of action of P. lobata and P. thomsonii, which provides a scientific basis for the development of new drugs for thrombogenic diseases and lays the foundation for the development of P. lobata and P. thomsonii herbal resources and P. lobata and P. thomsonii health products.
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Affiliation(s)
- Song Wang
- School of Pharmacy, Jiangxi University of Chinese Medicine, Nanchang, Jiangxi, 330004, China; Key Laboratory of Pharmacology of TCM in Jiangxi Province, Nanchang, Jiangxi, 330004, China
| | - Wei Yao
- School of Pharmacy, Jiangxi University of Chinese Medicine, Nanchang, Jiangxi, 330004, China; Key Laboratory of Pharmacology of TCM in Jiangxi Province, Nanchang, Jiangxi, 330004, China
| | - Xudong Zhu
- School of Pharmacy, Jiangxi University of Chinese Medicine, Nanchang, Jiangxi, 330004, China; Key Laboratory of Pharmacology of TCM in Jiangxi Province, Nanchang, Jiangxi, 330004, China
| | - Jingjing Wang
- School of Pharmacy, Jiangxi University of Chinese Medicine, Nanchang, Jiangxi, 330004, China; Key Laboratory of Pharmacology of TCM in Jiangxi Province, Nanchang, Jiangxi, 330004, China
| | - Longhui Lu
- School of Pharmacy, Jiangxi University of Chinese Medicine, Nanchang, Jiangxi, 330004, China; Key Laboratory of Pharmacology of TCM in Jiangxi Province, Nanchang, Jiangxi, 330004, China
| | - Na Zhu
- School of Pharmacy, Jiangxi University of Chinese Medicine, Nanchang, Jiangxi, 330004, China; Key Laboratory of Pharmacology of TCM in Jiangxi Province, Nanchang, Jiangxi, 330004, China
| | - Tong Lan
- School of Pharmacy, Jiangxi University of Chinese Medicine, Nanchang, Jiangxi, 330004, China
| | - Yunxia Kuang
- School of Pharmacy, Jiangxi University of Chinese Medicine, Nanchang, Jiangxi, 330004, China
| | - Weifeng Zhu
- Key Laboratory of Jiangxi University of Chinese Medicine, Ministry of Education, Nanchang, Jiangxi, 330004, China
| | - Ronghua Liu
- School of Pharmacy, Jiangxi University of Chinese Medicine, Nanchang, Jiangxi, 330004, China.
| | - Liping Huang
- School of Pharmacy, Jiangxi University of Chinese Medicine, Nanchang, Jiangxi, 330004, China; Key Laboratory of Pharmacology of TCM in Jiangxi Province, Nanchang, Jiangxi, 330004, China.
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Gu SZ, Bennett MR. Plaque Structural Stress: Detection, Determinants and Role in Atherosclerotic Plaque Rupture and Progression. Front Cardiovasc Med 2022; 9:875413. [PMID: 35872913 PMCID: PMC9300846 DOI: 10.3389/fcvm.2022.875413] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Accepted: 06/10/2022] [Indexed: 12/02/2022] Open
Abstract
Atherosclerosis remains a major cause of death worldwide, with most myocardial infarctions being due to rupture or erosion of coronary plaques. Although several imaging modalities can identify features that confer risk, major adverse cardiovascular event (MACE) rates attributable to each plaque are low, such that additional biomarkers are required to improve risk stratification at plaque and patient level. Coronary arteries are exposed to continual mechanical forces, and plaque rupture occurs when plaque structural stress (PSS) exceeds its mechanical strength. Prospective studies have shown that peak PSS is correlated with acute coronary syndrome (ACS) presentation, plaque rupture, and MACE, and provides additional prognostic information to imaging. In addition, PSS incorporates multiple variables, including plaque architecture, plaque material properties, and haemodynamic data into a defined solution, providing a more detailed overview of higher-risk lesions. We review the methods for calculation and determinants of PSS, imaging modalities used for modeling PSS, and idealized models that explore structural and geometric components that affect PSS. We also discuss current experimental and clinical data linking PSS to the natural history of coronary artery disease, and explore potential for refining treatment options and predicting future events.
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Affiliation(s)
- Sophie Z Gu
- Section of Cardiorespiratory Medicine, Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Martin R Bennett
- Section of Cardiorespiratory Medicine, Department of Medicine, University of Cambridge, Cambridge, United Kingdom
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Xi X, Liu J, Sun H, Xu K, Wang X, Zhang L, Du T, Liu J, Li B. Accurate Calculation of FFR Based on a Physics-Driven Fluid‐Structure Interaction Model. Front Physiol 2022; 13:861446. [PMID: 35492614 PMCID: PMC9039540 DOI: 10.3389/fphys.2022.861446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Accepted: 03/24/2022] [Indexed: 11/30/2022] Open
Abstract
Background: The conventional FFRct numerical calculation method uses a model with a multi-scale geometry based upon CFD, and rigid walls. Therefore, important interactions between the elastic vessel wall and blood flow are not routinely considered. Changes in the resistance of coronary microcirculation during hyperaemia are likewise not typically incorporated using a fluid–structure interaction (FSI) algorithm. It is likely that both have resulted in FFRct calculation errors. Objective: In this study we incorporated both the influence of vascular elasticity and coronary microcirculatory structure on FFR, to improve the accuracy of FFRct calculation. Thus, in this study, a physics-driven 3D–0D coupled model including fluid–structure interaction was established to calculate accurate FFRct values. Methods: Based upon a novel geometric multi-scale modeling technology, a FSI simulation approach was used. A lumped parameter model (0D) was used as the outlet boundary condition for the 3D FSI coronary artery model to incorporate physiological microcirculation, with bidirectional coupling between the two models. Results: The accuracy, sensitivity, specificity, and both positive and negative predictive values of FFRDC calculated based upon the coupled 3D–0D model were 86.7, 66.7, 84.6, 66.7, and 91.7%, respectively. Compared to the calculated value using the basic CFD model (MSE = 5.9%, accuracy rate = 80%), the FFRCFD calculated based on the coupled 3D–0D model has a smaller MSE of 1.9%. Conclusion: The physics-driven coupled 3D–0D model that incorporates fluid–structure interactions not only consider the influence of the elastic vessel wall on blood flow, but also provides reliable microvascular resistance boundary conditions for the 3D FSI model. This allows for a calculation that is based upon conditions that are closer to the physiological environment, and thus improves the accuracy of FFRct calculation. It is likely that more accurate information will provide an enhanced recommendation regarding percutaneous coronary intervention (PCI) in the clinic.
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Affiliation(s)
- Xiaolu Xi
- Department of Biomedical Engineering, Faculty of Environment and Life, Beijing University of Technology, Beijing, China
| | - Jincheng Liu
- Department of Biomedical Engineering, Faculty of Environment and Life, Beijing University of Technology, Beijing, China
| | - Hao Sun
- Department of Biomedical Engineering, Faculty of Environment and Life, Beijing University of Technology, Beijing, China
| | - Ke Xu
- Department of Biomedical Engineering, Faculty of Environment and Life, Beijing University of Technology, Beijing, China
| | - Xue Wang
- Department of Biomedical Engineering, Faculty of Environment and Life, Beijing University of Technology, Beijing, China
| | - Liyuan Zhang
- Department of Biomedical Engineering, Faculty of Environment and Life, Beijing University of Technology, Beijing, China
| | - Tianming Du
- Department of Biomedical Engineering, Faculty of Environment and Life, Beijing University of Technology, Beijing, China
| | - Jian Liu
- Cardiovascular Department, Peking University People’s Hospital, Beijing, China
| | - Bao Li
- Department of Biomedical Engineering, Faculty of Environment and Life, Beijing University of Technology, Beijing, China
- *Correspondence: Bao Li,
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Dilba K, van Dam-Nolen DHK, Korteland SA, van der Kolk AG, Kassem M, Bos D, Koudstaal PJ, Nederkoorn PJ, Hendrikse J, Kooi ME, Gijsen FJH, van der Steen AFW, van der Lugt A, Wentzel JJ. The Association Between Time-Varying Wall Shear Stress and the Development of Plaque Ulcerations in Carotid Arteries From the Plaque at Risk Study. Front Cardiovasc Med 2021; 8:732646. [PMID: 34869634 PMCID: PMC8636734 DOI: 10.3389/fcvm.2021.732646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 10/06/2021] [Indexed: 11/24/2022] Open
Abstract
Background and Purpose: Shear stress (WSS) is involved in the pathophysiology of atherosclerotic disease and might affect plaque ulceration. In this case-control study, we compared carotid plaques that developed a new ulcer during follow-up and plaques that remained silent for their exposure to time-dependent oscillatory shear stress parameters at baseline. Materials and Methods: Eighteen patients who underwent CTA and MRI of their carotid arteries at baseline and 2 years follow-up were included. These 18 patients consisted of six patients who demonstrated a new ulcer and 12 control patients selected from a larger cohort with similar MRI-based plaque characteristics as the ulcer group. (Oscillatory) WSS parameters [time average WSS, oscillatory shear index (OSI), and relative residence time (RRT)] were calculated using computational fluid dynamics applying the MRI-based geometry of the carotid arteries and compared among plaques (wall thickness>2 mm) with and without ulceration (Mann–Whitney U test) and ulcer-site vs. non-ulcer-site within the plaque (Wilcoxon signed rank test). More detailed analysis on ulcer cases was performed and the predictive value of oscillatory WSS parameters was calculated using linear and logistic mixed-effect regression models. Results: The ulcer group demonstrated no difference in maximum WSS [9.9 (6.6–18.5) vs. 13.6 (9.7–17.7) Pa, p = 0.349], a lower maximum OSI [0.04 (0.01–0.10) vs. 0.12 (0.06–0.20) p = 0.019] and lower maximum RRT [1.25 (0.78–2.03) Pa−1 vs. 2.93 (2.03–5.28) Pa−1, p = 0.011] compared to controls. The location of the ulcer (ulcer-site) within the plaque was not always at the maximal WSS, but demonstrated higher average WSS, lower average RRT and OSI at the ulcer-site compared to the non-ulcer-sites. High WSS (WSS>4.3 Pa) and low RRT (RRT < 0.25 Pa) were associated with ulceration with an odds ratio of 3.6 [CI 2.1–6.3] and 2.6 [CI 1.54–4.44] respectively, which remained significant after adjustment for wall thickness. Conclusion: In this explorative study, ulcers were not exclusively located at plaque regions exposed to the highest WSS, OSI, or RRT, but high WSS and low RRT regions had a significantly higher odds to present ulceration within the plaque even after adjustment for wall thickness.
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Affiliation(s)
- Kristine Dilba
- Department of Cardiology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, Netherlands.,Department of Radiology and Nuclear Medicine, Erasmus MC, University Medical Center Rotterdam, Rotterdam, Netherlands
| | - Dianne H K van Dam-Nolen
- Department of Radiology and Nuclear Medicine, Erasmus MC, University Medical Center Rotterdam, Rotterdam, Netherlands
| | - Suze-Anne Korteland
- Department of Cardiology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, Netherlands
| | - Anja G van der Kolk
- Department of Radiology, University Medical Center Utrecht, Utrecht, Netherlands
| | - Mohamed Kassem
- Department of Radiology and Nuclear Medicine, CARIM School for Cardiovascular Diseases, Maastricht University Medical Center+, Maastricht, Netherlands
| | - Daniel Bos
- Department of Radiology and Nuclear Medicine, Erasmus MC, University Medical Center Rotterdam, Rotterdam, Netherlands.,Department of Epidemiology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, Netherlands
| | - Peter J Koudstaal
- Department of Neurology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, Netherlands
| | - Paul J Nederkoorn
- Department of Neurology, University Medical Centers Amsterdam, Amsterdam, Netherlands
| | - Jeroen Hendrikse
- Department of Radiology, University Medical Center Utrecht, Utrecht, Netherlands
| | - M Eline Kooi
- Department of Radiology and Nuclear Medicine, CARIM School for Cardiovascular Diseases, Maastricht University Medical Center+, Maastricht, Netherlands
| | - Frank J H Gijsen
- Department of Cardiology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, Netherlands
| | - Anton F W van der Steen
- Department of Cardiology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, Netherlands
| | - Aad van der Lugt
- Department of Radiology and Nuclear Medicine, Erasmus MC, University Medical Center Rotterdam, Rotterdam, Netherlands
| | - Jolanda J Wentzel
- Department of Cardiology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, Netherlands
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Cai Y, Li Z. Mathematical modeling of plaque progression and associated microenvironment: How far from predicting the fate of atherosclerosis? COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2021; 211:106435. [PMID: 34619601 DOI: 10.1016/j.cmpb.2021.106435] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Accepted: 09/16/2021] [Indexed: 06/13/2023]
Abstract
Mathematical modeling contributes to pathophysiological research of atherosclerosis by helping to elucidate mechanisms and by providing quantitative predictions that can be validated. In turn, the complexity of atherosclerosis is well suited to quantitative approaches as it provides challenges and opportunities for new developments of modeling. In this review, we summarize the current 'state of the art' on the mathematical modeling of the effects of biomechanical factors and microenvironmental factors on the plaque progression, and its potential help in prediction of plaque development. We begin with models that describe the biomechanical environment inside and outside the plaque and its influence on its growth and rupture. We then discuss mathematical models that describe the dynamic evolution of plaque microenvironmental factors, such as lipid deposition, inflammation, smooth muscle cells migration and intraplaque hemorrhage, followed by studies on plaque growth and progression using these modelling approaches. Moreover, we present several key questions for future research. Mathematical models can complement experimental and clinical studies, but also challenge current paradigms, redefine our understanding of mechanisms driving plaque vulnerability and propose future potential direction in therapy for cardiovascular disease.
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Affiliation(s)
- Yan Cai
- School of Biological Sciences and Medical Engineering, Southeast University, Nanjing 210096, China.
| | - Zhiyong Li
- School of Biological Sciences and Medical Engineering, Southeast University, Nanjing 210096, China; School of Mechanical, Medical and Process Engineering, Queensland University of Technology, Brisbane, QLD 4001, Australia
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Bennati L, Vergara C, Domanin M, Malloggi C, Bissacco D, Trimarchi S, Silani V, Parati G, Casana R. A Computational Fluid-Structure Interaction Study for Carotids With Different Atherosclerotic Plaques. J Biomech Eng 2021; 143:1107993. [PMID: 33876184 DOI: 10.1115/1.4050910] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Indexed: 11/08/2022]
Abstract
Atherosclerosis is a systemic disease that leads to accumulation of deposits, known as atherosclerotic plaques, within the walls of the carotids. In particular, three types of plaque can be distinguished: soft, fibrous, and calcific. Most of the computational studies who investigated the interplay between the plaque and the blood flow on patient-specific geometries used nonstandard medical images to directly delineate and segment the plaque and its components. However, these techniques are not so widely available in the clinical practice. In this context, the aim of our work was twofold: (i) to propose a new geometric tool that allowed to reconstruct a plausible plaque in the carotids from standard images and (ii) to perform three-dimensional (3D) fluid-structure interaction (FSI) simulations where we compared some fluid-dynamic and structural quantities among 15 patients characterized by different typologies of plaque. Our results highlighted that both the morphology and the mechanical properties of different plaque components play a crucial role in determining the vulnerability of the plaque.
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Affiliation(s)
- Lorenzo Bennati
- Department of Surgery, Dentistry, Paediatrics and Gynaecology, University of Verona, Verona 37129, Italy
| | - Christian Vergara
- LABS, Dipartimento di Chimica, Materiali e Ingegneria Chimica "Giulio Natta," Politecnico di Milano, Milan 20133, Italy
| | - Maurizio Domanin
- Vascular Surgery Unit, IRCCS, Ospedale Maggiore Policlinico, Milan 20133, Italy; Department of Clinical Sciences and Community Health, University of Milan, Milan 20133, Italy
| | - Chiara Malloggi
- Laboratory of Research in Vascular Surgery, Istituto Auxologico Italiano, IRCCS, Milan 20133, Italy
| | - Daniele Bissacco
- Vascular Surgery Unit, IRCCS, Ospedale Maggiore Policlinico, Milan 20133, Italy
| | - Santi Trimarchi
- Vascular Surgery Unit, IRCCS, Ospedale Maggiore Policlinico, Milan 20133, Italy; Department of Clinical Sciences and Community Health, University of Milan, Milan 20133, Italy
| | - Vincenzo Silani
- Department of Neurology-Stroke Unit and Laboratory of Neuroscience, Ospedale San Luca, Istituto Auxologico Italiano, IRCCS, Milan 20133, Italy; Department of Pathophysiology and Transplantation, University of Milan, Milan 20133, Italy
| | - Gianfranco Parati
- Department of Cardiovascular, Neural and Metabolic Sciences, Ospedale San Luca, Istituto Auxologico Italiano, IRCCS, Milan 20133, Italy; Department of Medicine and Surgery, Università di Milano-Bicocca, Monza 20900, Italy
| | - Renato Casana
- Laboratory of Research in Vascular Surgery, Istituto Auxologico Italiano, IRCCS, Milan 20133, Italy; Department of Surgery, Istituto Auxologico Italiano, IRCCS, Milan 20133, Italy
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Identification of intra-individual variation in intracranial arterial flow by MRI and the effect on computed hemodynamic descriptors. MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE 2021; 34:659-666. [PMID: 33839985 DOI: 10.1007/s10334-021-00917-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 02/13/2021] [Accepted: 02/16/2021] [Indexed: 10/21/2022]
Abstract
OBJECTIVES To determine the intra-individual flow variation in serially acquired studies, and the influence of this variation on subsequent hemodynamic simulations using the inlet flow as a boundary condition. Author: Kindly check and confirm whether the corresponding authors are correctly identified.Confirmed. MATERIALS AND METHODS This prospective study included 51 patients (37 females and 14 males) with unruptured intracranial aneurysms who have received more than three times follow-up of 2D phase-contrast MR. The flow and velocity parameters were extracted to calculate the reproducibility and variation. Patient-specific computational fluid dynamics simulations were performed using the measured flows. RESULTS Intraclass correlation coefficients for mean and maximum velocity and flow parameters ranged from 0.77 to 0.90. A 10% CV of mean flow was identified. Variations of 10% in inlet flow resulted in hemodynamic changes including 41.41% of peak systolic wall shear stress; 39.13% of end-diastolic wall shear stress; 2.79% of low shear area at peak systole; 2.12% of low shear area at end diastole: 47.57% of time-averaged wall shear stress; and 0.17% of oscillatory shear index. CONCLUSION This study identified 10% of intra-individual mean flow variation on phase-contrast MR. Intra-individual flow variation resulted in a non-negligible variation in wall shear stress, but relatively small variation in low shear area in hemodynamic calculations.
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Settecase F, Rayz VL. Advanced vascular imaging techniques. HANDBOOK OF CLINICAL NEUROLOGY 2021; 176:81-105. [DOI: 10.1016/b978-0-444-64034-5.00016-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Blood flow simulations in patient-specific geometries of the carotid artery: A systematic review. J Biomech 2020; 111:110019. [PMID: 32905972 DOI: 10.1016/j.jbiomech.2020.110019] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 08/07/2020] [Accepted: 08/26/2020] [Indexed: 12/21/2022]
Abstract
Computational Fluid Dynamics (CFD) and Fluid-Structure Interaction (FSI) are currently widely applied in the study of blood flow parameters and their alterations under pathological conditions, which are important indicators for diagnosis of atherosclerosis. In this manuscript, a systematic review of the published literature was conducted, according to the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses, on the simulation studies of blood flow in patient-specific geometries of the carotid artery bifurcation. Scopus, PubMed and ScienceDirect databases were used in the literature search, which was completed on the 3rd of August 2020. Forty-nine articles were included after the selection process and were organized in two distinct categories: the CFD studies (36/49 articles), which comprise only the fluid analysis and the FSI studies (13/49 articles), which includes both fluid and Fluid-Structure domain in the analysis. The data of the research works was structured in different categories (Geometry, Viscosity models, Type of Flow, Boundary Conditions, Flow Parameters, Type of Solver and Validation). The aim of this systematic review is to demonstrate the methodology in the modelling, simulation and analysis of carotid blood flow and also identify potential gaps and challenges in this research field.
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12
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Xu K, Yu L, Wan J, Wang S, Lu H. The influence of the elastic modulus of the plaque in carotid artery on the computed results of FFRCT. Comput Methods Biomech Biomed Engin 2020; 23:201-211. [PMID: 31910646 DOI: 10.1080/10255842.2019.1710741] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- Kesong Xu
- Institute of Biomechanics, Department of Aeronautics and Astronautics, Fudan University, Shanghai, China
| | - Long Yu
- Institute of Biomechanics, Department of Aeronautics and Astronautics, Fudan University, Shanghai, China
| | - Jun Wan
- Interventional Department, Shanghai Jing'an District Central Hospital, Shanghai, China
| | - Shengzhang Wang
- Institute of Biomechanics, Department of Aeronautics and Astronautics, Fudan University, Shanghai, China
| | - Haiyan Lu
- Ultrasound Division of VIP Clinic Department, Dongfang Hospital Affiliated to Tongji University, Shanghai, China
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13
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Wang Q, Tang D, Wang L, Canton G, Wu Z, Hatsukami TS, Billiar KL, Yuan C. Combining morphological and biomechanical factors for optimal carotid plaque progression prediction: An MRI-based follow-up study using 3D thin-layer models. Int J Cardiol 2019; 293:266-271. [PMID: 31301863 DOI: 10.1016/j.ijcard.2019.07.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2019] [Revised: 05/24/2019] [Accepted: 07/02/2019] [Indexed: 11/24/2022]
Abstract
Plaque progression prediction is of fundamental significance to cardiovascular research and disease diagnosis, prevention, and treatment. Magnetic resonance image (MRI) data of carotid atherosclerotic plaques were acquired from 20 patients with consent obtained. 3D thin-layer models were constructed to calculate plaque stress and strain. Data for ten morphological and biomechanical risk factors were extracted for analysis. Wall thickness increase (WTI), plaque burden increase (PBI) and plaque area increase (PAI) were chosen as three measures for plaque progression. Generalized linear mixed models (GLMM) with 5-fold cross-validation strategy were used to calculate prediction accuracy and identify optimal predictor. The optimal predictor for PBI was the combination of lumen area (LA), plaque area (PA), lipid percent (LP), wall thickness (WT), maximum plaque wall stress (MPWS) and maximum plaque wall strain (MPWSn) with prediction accuracy = 1.4146 (area under the receiver operating characteristic curve (AUC) value is 0.7158), while PA, plaque burden (PB), WT, LP, minimum cap thickness, MPWS and MPWSn was the best for WTI (accuracy = 1.3140, AUC = 0.6552), and a combination of PA, PB, WT, MPWS, MPWSn and average plaque wall strain (APWSn) was the best for PAI with prediction accuracy = 1.3025 (AUC = 0.6657). The combinational predictors improved prediction accuracy by 9.95%, 4.01% and 1.96% over the best single predictors for PAI, PBI and WTI (AUC values improved by 9.78%, 9.45%, and 2.14%), respectively. This suggests that combining both morphological and biomechanical risk factors could lead to better patient screening strategies.
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Affiliation(s)
- Qingyu Wang
- School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China
| | - Dalin Tang
- School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China; Mathematical Sciences Department, Worcester Polytechnic Institute, Worcester, MA 01609, USA.
| | - Liang Wang
- School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China.
| | - Gador Canton
- Department of Mechanical Engineering, University of Washington, Seattle, WA 98195, USA.
| | - Zheyang Wu
- Mathematical Sciences Department, Worcester Polytechnic Institute, Worcester, MA 01609, USA.
| | - Thomas S Hatsukami
- Division of Vascular Surgery, University of Washington, Seattle, WA 98195, USA.
| | - Kristen L Billiar
- Biomedical Engineering Department, Worcester Polytechnic Institute, Worcester, MA 01609, USA.
| | - Chun Yuan
- Department of Radiology, University of Washington, Seattle, WA 98195, USA.
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14
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Rezvani-Sharif A, Tafazzoli-Shadpour M, Avolio A. Progressive changes of elastic moduli of arterial wall and atherosclerotic plaque components during plaque development in human coronary arteries. Med Biol Eng Comput 2018; 57:731-740. [PMID: 30374700 DOI: 10.1007/s11517-018-1910-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Accepted: 10/03/2018] [Indexed: 12/14/2022]
Abstract
Stiffness of the arterial wall and atherosclerotic plaque components is a determinant of the stress field within plaques, which has been suggested to be an indicator of plaque vulnerability. The diversity and inhomogeneous structure of atherosclerotic lesions complicate the characterization of plaque components. In the present study, stiffness of the arterial wall and atherosclerotic plaque components in human coronary arteries was examined in early and developed atherosclerotic lesions. The force-spectroscopy mode of the atomic force microscope and histological examination were used for determination of elastic moduli at specified locations within samples. Fibrous cap (E = 14.1 ± 3.8 kPa) showed lower stiffness than the fibrous tissue beneath the lipid pool (E = 17.6 ± 3.2 kPa). Calcification zones (E = 96.1 ± 18.8 kPa) and lipid pools (E = 2.7 ± 1.8 kPa) were the stiffest and softest components of atherosclerotic lesions, respectively. The increase of media stiffness (%44.8) and reduction of the elastic modulus of the internal elastic lamina (%28.9) was observed in coronary arteries. Moreover, significant differences were observed between the stiffness of medial layer in diseased parts and free-plaque segments in incomplete plaques of coronary arteries. Our results can be used for better understanding of remodeling mechanisms of the arterial wall with plaque development. Graphical abstract Stiffness alteration of the arterial wall and atherosclerotic plaque components with plaque development in coronary arteries.
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Affiliation(s)
- Alireza Rezvani-Sharif
- Faculty of Biomedical Engineering, Amirkabir University of Technology, Hafez Street, Tehran, Iran.,Department of Biomedical Science, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW, 2109, Australia
| | | | - Alberto Avolio
- Faculty of Biomedical Engineering, Amirkabir University of Technology, Hafez Street, Tehran, Iran
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15
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Onaizah O, Poepping TL, Zamir M. A model of blood supply to the brain via the carotid arteries: Effects of obstructive vs. sclerotic changes. Med Eng Phys 2017; 49:121-130. [PMID: 28917828 DOI: 10.1016/j.medengphy.2017.08.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2016] [Revised: 05/31/2017] [Accepted: 08/18/2017] [Indexed: 10/18/2022]
Abstract
The carotid artery is one of the major supply routes of blood to the brain and a common site of vascular disease. Obstructive and sclerotic disorders within the carotid artery impact local blood flow patterns as well as overall impedance and blood supply to the brain. A lumped parameter model and an experimental in-vitro flow loop were used to study the effects of local stenosis and stiffness in the carotid artery based on a family of phantoms with different degrees of stenosis and compliance. The model also allows independent examination of the effects of downstream resistance and compliance. Mild to moderate stenosis was found to lead to minimal (∼1%) reduction in blood supply to the brain. Reduction in mean internal carotid artery (ICA) flow was statistically significant (p< 0.01) only above 70% stenosis. On the other hand, a three-fold increase in stiffness of the carotid artery, as might occur in aging, was found to lead to a modest yet statistically significant reduction (p< 0.01) in mean ICA flow. Effects of changing downstream resistance and compliance were examined. For a given pressure waveform, reduction in downstream compliance led to altered waveform shape and reduction in peak systolic flow rates where the mean flow rates were not altered. Increased downstream resistance resulted in drastic reduction in mean flow rates.
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Affiliation(s)
- O Onaizah
- Department of Medical Biophysics, The University of Western Ontario, London, Canada
| | - T L Poepping
- Department of Medical Biophysics, The University of Western Ontario, London, Canada; Department of Physics and Astronomy, The University of Western Ontario, London, Canada
| | - M Zamir
- Department of Applied Mathematics, The University of Western Ontario, London, Canada; Department of Medical Biophysics, The University of Western Ontario, London, Canada.
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16
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Hazell GGJ, Peachey AMG, Teasdale JE, Sala-Newby GB, Angelini GD, Newby AC, White SJ. PI16 is a shear stress and inflammation-regulated inhibitor of MMP2. Sci Rep 2016; 6:39553. [PMID: 27996045 PMCID: PMC5171773 DOI: 10.1038/srep39553] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Accepted: 11/23/2016] [Indexed: 01/26/2023] Open
Abstract
Raised endothelial shear stress is protective against atherosclerosis but such protection may be lost at sites of inflammation. We found that four splice variants of the peptidase inhibitor 16 (PI16) mRNA are among the most highly shear stress regulated transcripts in human coronary artery endothelial cells (HCAECs), in vitro but that expression is reduced by inflammatory mediators TNFα and IL-1β. Immunohistochemistry demonstrated that PI16 is expressed in human coronary endothelium and in a subset of neointimal cells and medial smooth muscle cells. Adenovirus-mediated PI16 overexpression inhibits HCAEC migration and secreted matrix metalloproteinase (MMP) activity. Moreover, PI16 inhibits MMP2 in part by binding an exposed peptide loop above the active site. Our results imply that, at high endothelial shear stress, PI16 contributes to inhibition of protease activity; protection that can be reversed during inflammation.
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Affiliation(s)
- Georgina G J Hazell
- School of Clinical Sciences, University of Bristol, Bristol Royal Infirmary, Bristol, BS2 8HW, UK
| | - Alasdair M G Peachey
- School of Clinical Sciences, University of Bristol, Bristol Royal Infirmary, Bristol, BS2 8HW, UK
| | - Jack E Teasdale
- School of Clinical Sciences, University of Bristol, Bristol Royal Infirmary, Bristol, BS2 8HW, UK
| | - Graciela B Sala-Newby
- School of Clinical Sciences, University of Bristol, Bristol Royal Infirmary, Bristol, BS2 8HW, UK
| | - Gianni D Angelini
- School of Clinical Sciences, University of Bristol, Bristol Royal Infirmary, Bristol, BS2 8HW, UK
| | - Andrew C Newby
- School of Clinical Sciences, University of Bristol, Bristol Royal Infirmary, Bristol, BS2 8HW, UK
| | - Stephen J White
- School of Clinical Sciences, University of Bristol, Bristol Royal Infirmary, Bristol, BS2 8HW, UK.,School of Healthcare Science, Manchester Metropolitan University, John Dalton Building, Manchester M1 5GD, UK
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17
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Stress analysis of fracture of atherosclerotic plaques: crack propagation modeling. Med Biol Eng Comput 2016; 55:1389-1400. [DOI: 10.1007/s11517-016-1600-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Accepted: 11/28/2016] [Indexed: 12/19/2022]
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18
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Huang X, Yang C, Zheng J, Bach R, Muccigrosso D, Woodard PK, Tang D. 3D MRI-based multicomponent thin layer structure only plaque models for atherosclerotic plaques. J Biomech 2016; 49:2726-2733. [PMID: 27344199 DOI: 10.1016/j.jbiomech.2016.06.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Revised: 05/22/2016] [Accepted: 06/01/2016] [Indexed: 01/13/2023]
Abstract
MRI-based fluid-structure interactions (FSI) models for atherosclerotic plaques have been developed to perform mechanical analysis to investigate the association of plaque wall stress (PWS) with cardiovascular disease. However, the time consuming 3D FSI model construction process is a great hinder for its clinical implementations. In this study, a 3D thin-layer structure only (TLS) plaque model was proposed as an approximation with much less computational cost to 3D FSI models for better clinical implementation potential. 192 TLS models were constructed based on 192 ex vivo MRI Images of 12 human coronary atherosclerotic plaques. Plaque stresses were extracted from all lumen nodal points. The maximum value of Plaque wall stress (MPWS) and average value of plaque wall stress (APWS) of each slice were used to compare with those from corresponding FSI models. The relative errors for MPWS and APWS were 9.76% and 9.89%, respectively. Both MPWS and APWS values obtained from TLS models showed very good correlation with those from 3D FSI models. Correlation results from TLS models were in consistent with FSI models. Our results indicated that the proposed 3D TLS plaque models may be used as a good approximation to 3D FSI models with much less computational cost. With further validation, 3D TLS models may be possibly used to replace FSI models to save time and perform mechanical analysis for atherosclerotic plaques for clinical implementation.
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Affiliation(s)
- Xueying Huang
- School of Mathematical Sciences, Xiamen University, Xiamen, Fujian 361005, China; Fujian Provincial Key Laboratory of Mathematical Modeling and High-Performance Scientific Computation, Xiamen University, Xiamen, Fujian 361005 China; Department of Mathematical Sciences, Worcester Polytechnic Institute, MA 01609, USA.
| | - Chun Yang
- Department of Mathematical Sciences, Worcester Polytechnic Institute, MA 01609, USA; Network Technology Research Institute, China United Network Communications Co., Ltd., Beijing, China
| | - Jie Zheng
- Mallinkcrodt Institute of Radiology, Washington University, St. Louis, MO 63110, USA
| | - Richard Bach
- Cardiovascular Division, Washington University, St. Louis, MO 63110, USA
| | - David Muccigrosso
- Mallinkcrodt Institute of Radiology, Washington University, St. Louis, MO 63110, USA
| | - Pamela K Woodard
- Mallinkcrodt Institute of Radiology, Washington University, St. Louis, MO 63110, USA
| | - Dalin Tang
- Department of Mathematical Sciences, Worcester Polytechnic Institute, MA 01609, USA; School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China
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19
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Boekhoven RW, Peters MFJ, Rutten MCM, van Sambeek MR, van de Vosse FN, Lopata RGP. Inflation and Bi-Axial Tensile Testing of Healthy Porcine Carotid Arteries. ULTRASOUND IN MEDICINE & BIOLOGY 2016; 42:574-585. [PMID: 26598396 DOI: 10.1016/j.ultrasmedbio.2015.09.019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Revised: 09/16/2015] [Accepted: 09/16/2015] [Indexed: 06/05/2023]
Abstract
Knowledge of the intrinsic material properties of healthy and diseased arterial tissue components is of great importance in diagnostics. This study describes an in vitro comparison of 13 porcine carotid arteries using inflation testing combined with functional ultrasound and bi-axial tensile testing. The measured tissue behavior was described using both a linear, but geometrically non-linear, one-parameter (neo-Hookean) model and a two-parameter non-linear (Demiray) model. The shear modulus estimated using the linear model resulted in good agreement between the ultrasound and tensile testing methods, GUS = 25 ± 5.7 kPa and GTT = 23 ± 5.4 kPa. No significant correspondence was observed for the non-linear model aUS = 1.0 ± 2.7 kPa vs. aTT = 17 ± 8.8 kPa, p ∼ 0); however, the exponential parameters were in correspondence (bUS = 12 ± 4.2 vs. bTT = 10 ± 1.7, p > 0.05). Estimation of more complex models in vivo is cumbersome considering the sensitivity of the model parameters to small changes in measurement data and the absence of intraluminal pressure data, endorsing the use of a simple, linear model in vivo.
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Affiliation(s)
- Renate W Boekhoven
- Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Mathijs F J Peters
- Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Marcel C M Rutten
- Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Marc R van Sambeek
- Vascular Surgery, Catharina Hospital Eindhoven, Eindhoven, The Netherlands
| | - Frans N van de Vosse
- Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Richard G P Lopata
- Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands.
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20
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Teng Z, Yuan J, Feng J, Zhang Y, Brown AJ, Wang S, Lu Q, Gillard JH. The influence of constitutive law choice used to characterise atherosclerotic tissue material properties on computing stress values in human carotid plaques. J Biomech 2015; 48:3912-21. [PMID: 26472305 PMCID: PMC4655867 DOI: 10.1016/j.jbiomech.2015.09.023] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Revised: 09/16/2015] [Accepted: 09/24/2015] [Indexed: 01/01/2023]
Abstract
Calculating high stress concentration within carotid atherosclerotic plaques has been shown to be complementary to anatomical features in assessing vulnerability. Reliability of stress calculation may depend on the constitutive laws/strain energy density functions (SEDFs) used to characterize tissue material properties. Different SEDFs, including neo-Hookean, one-/two-term Ogden, Yeoh, 5-parameter Mooney–Rivlin, Demiray and modified Mooney–Rivlin, have been used to describe atherosclerotic tissue behavior. However, the capacity of SEDFs to fit experimental data and the difference in the stress calculation remains unexplored. In this study, seven SEDFs were used to fit the stress–stretch data points of media, fibrous cap, lipid and intraplaque hemorrhage/thrombus obtained from 21 human carotid plaques. Semi-analytic solution, 2D structure-only and 3D fully coupled fluid-structure interaction (FSI) analyses were used to quantify stress using different SEDFs and the related material stability examined. Results show that, except for neo-Hookean, all other six SEDFs fitted the experimental points well, with vessel stress distribution in the circumferential and radial directions being similar. 2D structural-only analysis was successful for all seven SEDFs, but 3D FSI were only possible with neo-Hookean, Demiray and modified Mooney–Rivlin models. Stresses calculated using Demiray and modified Mooney–Rivlin models were nearly identical. Further analyses indicated that the energy contours of one-/two-term Ogden and 5-parameter Mooney–Rivlin models were not strictly convex and the material stability indictors under homogeneous deformations were not always positive. In conclusion, considering the capacity in characterizing material properties and stabilities, Demiray and modified Mooney–Rivlin SEDF appear practical choices for mechanical analyses to predict the critical mechanical conditions within carotid atherosclerotic plaques.
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Affiliation(s)
- Zhongzhao Teng
- Department of Radiology, University of Cambridge, UK; Department of Engineering, University of Cambridge, UK.
| | - Jianmin Yuan
- Department of Radiology, University of Cambridge, UK
| | - Jiaxuan Feng
- Department of Vascular Surgery, Changhai Hospital, Shanghai, China
| | - Yongxue Zhang
- Department of Vascular Surgery, Changhai Hospital, Shanghai, China
| | - Adam J Brown
- Division of Cardiovascular Medicine, University of Cambridge, UK
| | - Shuo Wang
- Department of Radiology, University of Cambridge, UK
| | - Qingsheng Lu
- Department of Vascular Surgery, Changhai Hospital, Shanghai, China
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21
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Pedrigi RM, de Silva R, Bovens SM, Mehta VV, Petretto E, Krams R. Thin-Cap Fibroatheroma Rupture Is Associated With a Fine Interplay of Shear and Wall Stress. Arterioscler Thromb Vasc Biol 2014; 34:2224-31. [DOI: 10.1161/atvbaha.114.303426] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
In this review, we summarized the effect of mechanical factors (shear and wall stress) on thin-cap fibroatheroma formation and rupture. To make this review understandable for a biology-oriented audience, we start with detailed definitions of relevant mechanical metrics. We then describe how biomechanics has supported histopathologic efforts to understand the basis of plaque rupture. In addition to plaque rupture, biomechanics also contributes toward the progression of thin-cap fibroatheroma through a multitude of reported mechanobiological mechanisms. We thus propose a new mechanism whereby both shear stress and wall stress interact to create thin-cap fibroatheromas. Specifically, when regions of certain blood flow and wall mechanical stimuli coincide, they synergistically create inflammation within the cellular environment that can lead to thin-cap fibroatheroma rupture. A consequence of this postulate is that local shear stress is not sufficient to cause rupture, but it must coincide with regions of local tissue stiffening and stress concentrations that can occur during plaque progression. Because such changes to the wall mechanics occur over a micrometer scale, high spatial resolution imaging techniques will be necessary to evaluate this hypothesis and ultimately predict plaque rupture in a clinical environment.
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Affiliation(s)
- Ryan M. Pedrigi
- From the Department of Bioengineering, Imperial College London, London, United Kingdom (R.M.P., S.M.B., V.V.M., R.K.); NHLI, Imperial College London and NIHR Cardiovascular Biomedical Research Unit, Royal Brompton and Harefield NHS Foundation Trust, London, United Kingdom (R.d.S.); and MRC-Clinical Sciences Centre, Imperial College London, London, United Kingdom (E.P.)
| | - Ranil de Silva
- From the Department of Bioengineering, Imperial College London, London, United Kingdom (R.M.P., S.M.B., V.V.M., R.K.); NHLI, Imperial College London and NIHR Cardiovascular Biomedical Research Unit, Royal Brompton and Harefield NHS Foundation Trust, London, United Kingdom (R.d.S.); and MRC-Clinical Sciences Centre, Imperial College London, London, United Kingdom (E.P.)
| | - Sandra M. Bovens
- From the Department of Bioengineering, Imperial College London, London, United Kingdom (R.M.P., S.M.B., V.V.M., R.K.); NHLI, Imperial College London and NIHR Cardiovascular Biomedical Research Unit, Royal Brompton and Harefield NHS Foundation Trust, London, United Kingdom (R.d.S.); and MRC-Clinical Sciences Centre, Imperial College London, London, United Kingdom (E.P.)
| | - Vikram V. Mehta
- From the Department of Bioengineering, Imperial College London, London, United Kingdom (R.M.P., S.M.B., V.V.M., R.K.); NHLI, Imperial College London and NIHR Cardiovascular Biomedical Research Unit, Royal Brompton and Harefield NHS Foundation Trust, London, United Kingdom (R.d.S.); and MRC-Clinical Sciences Centre, Imperial College London, London, United Kingdom (E.P.)
| | - Enrico Petretto
- From the Department of Bioengineering, Imperial College London, London, United Kingdom (R.M.P., S.M.B., V.V.M., R.K.); NHLI, Imperial College London and NIHR Cardiovascular Biomedical Research Unit, Royal Brompton and Harefield NHS Foundation Trust, London, United Kingdom (R.d.S.); and MRC-Clinical Sciences Centre, Imperial College London, London, United Kingdom (E.P.)
| | - Rob Krams
- From the Department of Bioengineering, Imperial College London, London, United Kingdom (R.M.P., S.M.B., V.V.M., R.K.); NHLI, Imperial College London and NIHR Cardiovascular Biomedical Research Unit, Royal Brompton and Harefield NHS Foundation Trust, London, United Kingdom (R.d.S.); and MRC-Clinical Sciences Centre, Imperial College London, London, United Kingdom (E.P.)
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22
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Kefayati S, Milner JS, Holdsworth DW, Poepping TL. In vitro shear stress measurements using particle image velocimetry in a family of carotid artery models: effect of stenosis severity, plaque eccentricity, and ulceration. PLoS One 2014; 9:e98209. [PMID: 25007248 PMCID: PMC4090132 DOI: 10.1371/journal.pone.0098209] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Accepted: 04/30/2014] [Indexed: 01/15/2023] Open
Abstract
Atherosclerotic disease, and the subsequent complications of thrombosis and plaque rupture, has been associated with local shear stress. In the diseased carotid artery, local variations in shear stress are induced by various geometrical features of the stenotic plaque. Greater stenosis severity, plaque eccentricity (symmetry) and plaque ulceration have been associated with increased risk of cerebrovascular events based on clinical trial studies. Using particle image velocimetry, the levels and patterns of shear stress (derived from both laminar and turbulent phases) were studied for a family of eight matched-geometry models incorporating independently varied plaque features - i.e. stenosis severity up to 70%, one of two forms of plaque eccentricity, and the presence of plaque ulceration). The level of laminar (ensemble-averaged) shear stress increased with increasing stenosis severity resulting in 2-16 Pa for free shear stress (FSS) and approximately double (4-36 Pa) for wall shear stress (WSS). Independent of stenosis severity, marked differences were found in the distribution and extent of shear stress between the concentric and eccentric plaque formations. The maximum WSS, found at the apex of the stenosis, decayed significantly steeper along the outer wall of an eccentric model compared to the concentric counterpart, with a 70% eccentric stenosis having 249% steeper decay coinciding with the large outer-wall recirculation zone. The presence of ulceration (in a 50% eccentric plaque) resulted in both elevated FSS and WSS levels that were sustained longer (∼20 ms) through the systolic phase compared to the non-ulcerated counterpart model, among other notable differences. Reynolds (turbulent) shear stress, elevated around the point of distal jet detachment, became prominent during the systolic deceleration phase and was widely distributed over the large recirculation zone in the eccentric stenoses.
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Affiliation(s)
- Sarah Kefayati
- Department of Physics and Astronomy, University of Western Ontario, London, ON, Canada
| | - Jaques S. Milner
- Imaging Research Laboratories, Robarts Research Institute, London, ON, Canada
| | - David W. Holdsworth
- Imaging Research Laboratories, Robarts Research Institute, London, ON, Canada
- Department of Surgery, University of Western Ontario, London, ON, Canada
| | - Tamie L. Poepping
- Department of Physics and Astronomy, University of Western Ontario, London, ON, Canada
- Imaging Research Laboratories, Robarts Research Institute, London, ON, Canada
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23
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Huang Y, Teng Z, Sadat U, Graves MJ, Bennett MR, Gillard JH. The influence of computational strategy on prediction of mechanical stress in carotid atherosclerotic plaques: comparison of 2D structure-only, 3D structure-only, one-way and fully coupled fluid-structure interaction analyses. J Biomech 2014; 47:1465-71. [PMID: 24529358 PMCID: PMC3989027 DOI: 10.1016/j.jbiomech.2014.01.030] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Revised: 01/15/2014] [Accepted: 01/15/2014] [Indexed: 11/15/2022]
Abstract
BACKGROUND Compositional and morphological features of carotid atherosclerotic plaques provide complementary information to luminal stenosis in predicting clinical presentations. However, they alone cannot predict cerebrovascular risk. Mechanical stress within the plaque induced by cyclical changes in blood pressure has potential to assess plaque vulnerability. Various modeling strategies have been employed to predict stress, including 2D and 3D structure-only, 3D one-way and fully coupled fluid-structure interaction (FSI) simulations. However, differences in stress predictions using different strategies have not been assessed. METHODS Maximum principal stress (Stress-P1) within 8 human carotid atherosclerotic plaques was calculated based on geometry reconstructed from in vivo computerized tomography and high resolution, multi-sequence magnetic resonance images. Stress-P1 within the diseased region predicted by 2D and 3D structure-only, and 3D one-way FSI simulations were compared to 3D fully coupled FSI analysis. RESULTS Compared to 3D fully coupled FSI, 2D structure-only simulation significantly overestimated stress level (94.1 kPa [65.2, 117.3] vs. 85.5 kPa [64.4, 113.6]; median [inter-quartile range], p=0.0004). However, when slices around the bifurcation region were excluded, stresses predicted by 2D structure-only simulations showed a good correlation (R(2)=0.69) with values obtained from 3D fully coupled FSI analysis. 3D structure-only model produced a small yet statistically significant stress overestimation compared to 3D fully coupled FSI (86.8 kPa [66.3, 115.8] vs. 85.5 kPa [64.4, 113.6]; p<0.0001). In contrast, one-way FSI underestimated stress compared to 3D fully coupled FSI (78.8 kPa [61.1, 100.4] vs. 85.5 kPa [64.4, 113.7]; p<0.0001). CONCLUSIONS A 3D structure-only model seems to be a computationally inexpensive yet reasonably accurate approximation for stress within carotid atherosclerotic plaques with mild to moderate luminal stenosis as compared to fully coupled FSI analysis.
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Affiliation(s)
- Yuan Huang
- University Departments of Radiology, University of Cambridge, UK
| | - Zhongzhao Teng
- University Departments of Radiology, University of Cambridge, UK; Department of Engineering, University of Cambridge, UK.
| | - Umar Sadat
- Department of Surgery, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
| | - Martin J Graves
- University Departments of Radiology, University of Cambridge, UK
| | - Martin R Bennett
- Division of Cardiovascular Medicine, University of Cambridge, UK
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Huang X, Yang C, Canton G, Ferguson M, Yuan C, Tang D. Quantifying effect of intraplaque hemorrhage on critical plaque wall stress in human atherosclerotic plaques using three-dimensional fluid-structure interaction models. J Biomech Eng 2014; 134:121004. [PMID: 23363206 DOI: 10.1115/1.4007954] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Recent magnetic resonance studies have indicated that intraplaque hemorrhage (IPH) may accelerate plaque progression and play an important role in plaque destabilization. However, the impact of hemorrhage on critical plaque wall stress (CPWS) and strain (CPWSn) has yet to be determined. The objective of this study was to assess the effect of the presence and size of IPH on wall mechanics. The magnetic resonance image (MRI) of one patient with histology-confirmed IPH was used to build eight 3D fluid-structure interaction (FSI) models by altering the dimensions of the existing IPH. As a secondary end point, the combined effect of IPH and fibrous cap thickness (FCT) was assessed. A volume curve fitting method (VCFM) was applied to generate a mesh that would guarantee numerical convergence. Plaque wall stress (PWS), strain (PWSn), and flow shear stress (FSS) were extracted from all nodal points on the lumen surface for analysis. Keeping other conditions unchanged, the presence of intraplaque hemorrhage caused a significant increase (27.5%) in CPWS; reduced FCT caused an increase of 22.6% of CPWS. Similar results were found for CPWSn. Furthermore, combination of IPH presence, reduced FCT, and increased IPH volume caused an 85% and 75% increase in CPWS and CPWSn, respectively. These results show that intraplaque hemorrhage has considerable impact on plaque stress and strain conditions and accurate quantification of IPH could lead to more accurate assessment of plaque vulnerability. Large-scale studies are needed to further validate our findings.
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Affiliation(s)
- Xueying Huang
- School of Mathematical Sciences, Xiamen University, Xiamen, Fujian 361005, PRC.
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Teng Z, Sadat U, Brown AJ, Gillard JH. Plaque hemorrhage in carotid artery disease: pathogenesis, clinical and biomechanical considerations. J Biomech 2014; 47:847-58. [PMID: 24485514 PMCID: PMC3994507 DOI: 10.1016/j.jbiomech.2014.01.013] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/13/2014] [Indexed: 12/21/2022]
Abstract
Stroke remains the most prevalent disabling illness today, with internal carotid artery luminal stenosis due to atheroma formation responsible for the majority of ischemic cerebrovascular events. Severity of luminal stenosis continues to dictate both patient risk stratification and the likelihood of surgical intervention. But there is growing evidence to suggest that plaque morphology may help improve pre-existing risk stratification criteria. Plaque components such a fibrous tissue, lipid rich necrotic core and calcium have been well investigated but plaque hemorrhage (PH) has been somewhat overlooked. In this review we discuss the pathogenesis of PH, its role in dictating plaque vulnerability, PH imaging techniques, marterial properties of atherosclerotic tissues, in particular, those obtained based on in vivo measurements and effect of PH in modulating local biomechanics.
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Affiliation(s)
- Zhongzhao Teng
- University Department of Radiology, University of Cambridge, UK; Department of Engineering, University of Cambridge, UK.
| | - Umar Sadat
- Department of Surgery, Cambridge University Hospitals NHS Foundation Trust, UK
| | - Adam J Brown
- Department of Cardiovascular Medicine, University of Cambridge, UK
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Huang X, Yang C, Zheng J, Bach R, Muccigrosso D, Woodard PK, Tang D. Higher critical plaque wall stress in patients who died of coronary artery disease compared with those who died of other causes: a 3D FSI study based on ex vivo MRI of coronary plaques. J Biomech 2013; 47:432-7. [PMID: 24345380 DOI: 10.1016/j.jbiomech.2013.11.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2013] [Revised: 10/08/2013] [Accepted: 11/06/2013] [Indexed: 12/16/2022]
Abstract
Mechanical forces play an important role in the rupture of vulnerable plaques. This process is often associated with cardiovascular syndromes, such as heart attack and stroke. In this study, magnetic resonance imaging (MRI)-based models were used to investigate the association between plaque wall stress (PWS) and coronary artery disease (CAD). Ex vivo MRI data of coronary plaques from 12 patients were used to construct 12 three-dimensional (3D) fluid-structure interaction (FSI) computational models. Six of the patients had died from CAD and six had died from non-CAD causes. PWS was assessed using all nodal points on the lumen surface of each plaque. The maximum PWS from all possible vulnerable sites of each plaque was defined as the 3D critical plaque wall stress (CPWS). Mean 3D CPWS in the CAD group was 94.3% higher than that in the non-CAD group (265.6 vs. 136.7 kPa, P=0.0029). There was no statistically significant difference in global maximum plaque wall stress (GMPWS) between the two groups (P=0.347). There was also no statistically significant difference in plaque burden between the CAD group (84.4±5%) and the non-CAD group (82.0±8%, P=0.552). The results indicate that plaques from patients who died from CAD were associated with higher CPWS compared with those from patients who died from non-CAD causes. With further validation, analysis of CPWS may prove to be an important component in assessment of plaque vulnerability.
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Affiliation(s)
- Xueying Huang
- School of Mathematical Sciences, Xiamen University, 422 South Siming Road, Xiamen, Fujian 361005, China; Department of Mathematical Sciences, Worcester Polytechnic Institute, MA 01609, USA.
| | - Chun Yang
- Department of Mathematical Sciences, Worcester Polytechnic Institute, MA 01609, USA; China United Network Communications Co., Ltd., Beijing 100048, China
| | - Jie Zheng
- Mallinkcrodt Institute of Radiology, Washington University, St. Louis, MO 63110, USA
| | - Richard Bach
- Cardiovascular Division, Washington University, St. Louis, MO 63110, USA
| | - David Muccigrosso
- Mallinkcrodt Institute of Radiology, Washington University, St. Louis, MO 63110, USA
| | - Pamela K Woodard
- Mallinkcrodt Institute of Radiology, Washington University, St. Louis, MO 63110, USA
| | - Dalin Tang
- Department of Mathematical Sciences, Worcester Polytechnic Institute, MA 01609, USA
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Boekhoven RW, Lopata RGP, van Sambeek MR, van de Vosse FN, Rutten MCM. A novel experimental approach for three-dimensional geometry assessment of calcified human stenotic arteries in vitro. ULTRASOUND IN MEDICINE & BIOLOGY 2013; 39:1875-1886. [PMID: 23910903 DOI: 10.1016/j.ultrasmedbio.2013.03.019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Revised: 01/31/2013] [Accepted: 03/14/2013] [Indexed: 06/02/2023]
Abstract
To improve diagnosis and understanding of the risk of rupture of atherosclerotic plaque, new strategies to realistically determine mechanical properties of atherosclerotic plaque need to be developed. In this study, an in vitro experimental method is proposed for accurate 3-D assessment of (diseased) vessel geometry using ultrasound. The method was applied to a vascular phantom, a healthy porcine carotid artery and human carotid endarterectomy specimens (n = 6). Vessel segments were pressure fixed and rotated in 10 ° steps. Longitudinal cross sections were imaged over 360 °. Findings were validated using micro-computed tomography (μCT). Results show good agreement between ultrasound and μCT-based geometries of the different segment types (ISI phantom = 0.94, ISI healthy = 0.79, ISI diseased = 0.75-0.80). The method does not suffer from acoustic shadowing effects present when imaging stenotic segments and allows future dynamic measurements to determine mechanical properties of atherosclerotic plaque in an in vitro setting.
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Affiliation(s)
- Renate W Boekhoven
- Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands.
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Cardoso L, Weinbaum S. Changing views of the biomechanics of vulnerable plaque rupture: a review. Ann Biomed Eng 2013; 42:415-31. [PMID: 23842694 DOI: 10.1007/s10439-013-0855-x] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Accepted: 06/20/2013] [Indexed: 12/21/2022]
Abstract
This review examines changing perspectives on the biomechanics of vulnerable plaque rupture over the past 25 years from the first finite element analyses (FEA) showing that the presence of a lipid pool significantly increases the local tissue stress in the atheroma cap to the latest imaging and 3D FEA studies revealing numerous microcalcifications in the cap proper and a new paradigm for cap rupture. The first part of the review summarizes studies describing the role of the fibrous cap thickness, tissue properties, and lesion geometry as main determinants of the risk of rupture. Advantages and limitations of current imaging technologies for assessment of vulnerable plaques are also discussed. However, the basic paradoxes as to why ruptures frequently did not coincide with location of PCS and why caps >65 μm thickness could rupture at tissue stresses significantly below the 300 kPa critical threshold still remained unresolved. The second part of the review describes recent studies in the role of microcalcifications, their origin, shape, and clustering in explaining these unresolved issues including the actual mechanism of rupture due to the explosive growth of tiny voids (cavitation) in local regions of high stress concentration between closely spaced microinclusions oriented along their tensile axis.
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Affiliation(s)
- Luis Cardoso
- Department of Biomedical Engineering, The City College of New York, Steinman Hall, 160 Convent Ave, New York, NY, 10031, USA
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29
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Computer Simulations in Stroke Prevention: Design Tools and Virtual Strategies Towards Procedure Planning. Cardiovasc Eng Technol 2013. [DOI: 10.1007/s13239-013-0134-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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30
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High wall shear stress and spatial gradients in vascular pathology: a review. Ann Biomed Eng 2012; 41:1411-27. [PMID: 23229281 DOI: 10.1007/s10439-012-0695-0] [Citation(s) in RCA: 225] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2012] [Accepted: 11/06/2012] [Indexed: 12/18/2022]
Abstract
Cardiovascular pathologies such as intracranial aneurysms (IAs) and atherosclerosis preferentially localize to bifurcations and curvatures where hemodynamics are complex. While extensive knowledge about low wall shear stress (WSS) has been generated in the past, due to its strong relevance to atherogenesis, high WSS (typically >3 Pa) has emerged as a key regulator of vascular biology and pathology as well, receiving renewed interests. As reviewed here, chronic high WSS not only stimulates adaptive outward remodeling, but also contributes to saccular IA formation (at bifurcation apices or outer curves) and atherosclerotic plaque destabilization (in stenosed vessels). Recent advances in understanding IA pathogenesis have shed new light on the role of high WSS in pathological vascular remodeling. In complex geometries, high WSS can couple with significant spatial WSS gradient (WSSG). A combination of high WSS and positive WSSG has been shown to trigger aneurysm initiation. Since endothelial cells (ECs) are sensors of WSS, we have begun to elucidate EC responses to high WSS alone and in combination with WSSG. Understanding such responses will provide insight into not only aneurysm formation, but also plaque destabilization and other vascular pathologies and potentially lead to improved strategies for disease management and novel targets for pharmacological intervention.
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Maldonado N, Kelly-Arnold A, Vengrenyuk Y, Laudier D, Fallon JT, Virmani R, Cardoso L, Weinbaum S. A mechanistic analysis of the role of microcalcifications in atherosclerotic plaque stability: potential implications for plaque rupture. Am J Physiol Heart Circ Physiol 2012; 303:H619-28. [PMID: 22777419 DOI: 10.1152/ajpheart.00036.2012] [Citation(s) in RCA: 167] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The role of microcalcifications (μCalcs) in the biomechanics of vulnerable plaque rupture is examined. Our laboratory previously proposed (Ref. 44), using a very limited tissue sample, that μCalcs embedded in the fibrous cap proper could significantly increase cap instability. This study has been greatly expanded. Ninety-two human coronary arteries containing 62 fibroatheroma were examined using high-resolution microcomputed tomography at 6.7-μm resolution and undecalcified histology with special emphasis on calcified particles <50 μm in diameter. Our results reveal the presence of thousands of μCalcs, the vast majority in lipid pools where they are not dangerous. However, 81 μCalcs were also observed in the fibrous caps of nine of the fibroatheroma. All 81 of these μCalcs were analyzed using three-dimensional finite-element analysis, and the results were used to develop important new clinical criteria for cap stability. These criteria include variation of the Young's modulus of the μCalc and surrounding tissue, μCalc size, and clustering. We found that local tissue stress could be increased fivefold when μCalcs were closely spaced, and the peak circumferential stress in the thinnest nonruptured cap (66 μm) if no μCalcs were present was only 107 kPa, far less than the proposed minimum rupture threshold of 300 kPa. These results and histology suggest that there are numerous μCalcs < 15 μm in the caps, not visible at 6.7-μm resolution, and that our failure to find any nonruptured caps between 30 and 66 μm is a strong indication that many of these caps contained μCalcs.
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Affiliation(s)
- Natalia Maldonado
- Department of Biomedical Engineering, The City College of New York, The City University of New York, New York, New York 10031, USA
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Belzacq T, Avril S, Leriche E, Delache A. Mechanical action of the blood onto atheromatous plaques: influence of the stenosis shape and morphology. Comput Methods Biomech Biomed Engin 2012; 17:527-38. [PMID: 22757631 DOI: 10.1080/10255842.2012.697898] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
The vulnerability of atheromatous plaques in the carotid artery may be related to several factors, the most important being the degree of severity of the endoluminal stenosis and the thickness of the fibrous cap. It has recently been shown that the plaque length can also affect the mechanical response significantly. However, in their study on the effect of the plaque length, the authors did not consider the variations of the plaque morphology and the shape irregularities that may exist independently of the plaque length. These aspects are developed in this paper. The mechanical interactions between the blood flow and an atheromatous plaque are studied through a numerical model considering fluid-structure interaction. The simulation is achieved using the arbitrary Lagrangian-Eulerian scheme in the COMSOL TM commercial finite element package. The stenosis severity and the plaque length are, respectively, set to 45% and 15 mm. Different shapes of the stenosis are modelled, considering irregularities made of several bumps over the plaque. The resulting flow patterns, wall shear stresses, plaque deformations and stresses in the fibrous cap reveal that the effects of the blood flow are amplified if the slope upstream stenosis is steep or if the plaque morphology is irregular with bumps. More specifically, the maximum stress in the fibrous cap is 50% larger for a steep slope than for a gentle slope. These results offer new perspectives for considering the shape of plaques in the evaluation of the vulnerability.
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Affiliation(s)
- Tristan Belzacq
- a Ecole Nationale Supérieure des Mines, Centre Ingénierie et Santé , CNRS UMR 5146, 158 Cours Fauriel, 42023 Saint-Etienne Cedex 2 , France
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Analysis of carotid artery plaque and wall boundaries on CT images by using a semi-automatic method based on level set model. Neuroradiology 2012; 54:1207-14. [PMID: 22562690 DOI: 10.1007/s00234-012-1040-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2011] [Accepted: 04/05/2012] [Indexed: 10/28/2022]
Abstract
INTRODUCTION The purpose of this study was to evaluate the potentialities of a semi-automated technique in the detection and measurement of the carotid artery plaque. METHODS Twenty-two consecutive patients (18 males, 4 females; mean age 62 years) examined with MDCTA from January 2011 to March 2011 were included in this retrospective study. Carotid arteries are examined with a 16-multi-detector-row CT system, and for each patient, the most diseased carotid was selected. In the first phase, the carotid plaque was identified and one experienced radiologist manually traced the inner and outer boundaries by using polyline and radial distance method (PDM and RDM, respectively). In the second phase, the carotid inner and outer boundaries were traced with an automated algorithm: level-set-method (LSM). Data were compared by using Pearson rho correlation, Bland-Altman, and regression. RESULTS A total of 715 slices were analyzed. The mean thickness of the plaque using the reference PDM was 1.86 mm whereas using the LSM-PDM was 1.96 mm; using the reference RDM was 2.06 mm whereas using the LSM-RDM was 2.03 mm. The correlation values between the references, the LSM, the PDM and the RDM were 0.8428, 0.9921, 0.745 and 0.6425. Bland-Altman demonstrated a very good agreement in particular with the RDM method. CONCLUSION Results of our study indicate that LSM method can automatically measure the thickness of the plaque and that the best results are obtained with the RDM. Our results suggest that advanced computer-based algorithms can identify and trace the plaque boundaries like an experienced human reader.
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Peter DA, Alemu Y, Xenos M, Weisberg O, Avneri I, Eshkol M, Oren T, Elazar M, Assaf Y, Bluestein D. Fluid Structure Interaction With Contact Surface Methodology for Evaluation of Endovascular Carotid Implants for Drug-Resistant Hypertension Treatment. J Biomech Eng 2012; 134:041001. [DOI: 10.1115/1.4006339] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Drug-resistant hypertensive patients may be treated by mechanical stimulation of stretch-sensitive baroreceptors located in the sinus of carotid arteries. To evaluate the efficacy of endovascular devices to stretch the carotid sinus such that the induced strain might trigger baroreceptors to increase action potential firing rate and thereby reduce systemic blood pressure, numerical simulations were conducted of devices deployed in subject-specific carotid models. Two models were chosen—a typical physiologic carotid and a diminutive atypical physiologic model representing a clinically worst case scenario—to evaluate the effects of device deployment in normal and extreme cases, respectively. Based on the anatomical dimensions of the carotids, two different device sizes were chosen out of five total device sizes available. A fluid structure interaction (FSI) simulation methodology with contact surface between the device and the arterial wall was implemented for resolving the stresses and strains induced by device deployment. Results indicate that device deployment in the carotid sinus of the physiologic model induces an increase of 2.5% and 7.5% in circumferential and longitudinal wall stretch, respectively, and a maximum of 54% increase in von Mises arterial stress at the sinus wall baroreceptor region. The second device, deployed in the diminutive carotid model, induces an increase of 6% in both circumferential and longitudinal stretch and a 50% maximum increase in von Mises stress at the sinus wall baroreceptor region. Device deployment has a minimal effect on blood-flow patterns, indicating that it does not adversely affect carotid bifurcation hemodynamics in the physiologic model. In the smaller carotid model, deployment of the device lowers wall shear stress at sinus by 16% while accelerating flow entering the external carotid artery branch. Our FSI simulations of carotid arteries with deployed device show that the device induces localized increase in wall stretch at the sinus, suggesting that this will activate baroreceptors and subsequently may control hypertension in drug-resistant hypertensive patients, with no consequential deleterious effects on the carotid sinus hemodynamics.
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Affiliation(s)
- Dinesh A. Peter
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794
| | - Yared Alemu
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794
| | - Michalis Xenos
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794
| | | | | | | | - Tal Oren
- Vascular Dynamics Ltd., Herzelia, Israel
| | | | | | - Danny Bluestein
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794
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Belzacq T, Avril S, Leriche E, Delache A. A numerical parametric study of the mechanical action of pulsatile blood flow onto axisymmetric stenosed arteries. Med Eng Phys 2012; 34:1483-95. [PMID: 22464939 DOI: 10.1016/j.medengphy.2012.02.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2011] [Revised: 12/24/2011] [Accepted: 02/19/2012] [Indexed: 10/28/2022]
Abstract
In the present paper, a fluid-structure interaction model is developed, questioning how the mechanical action of the blood onto an atheromatous plaque is affected by the length and the severity of the stenosis. An axisymmetric model is considered. The fluid is assumed Newtonian. The plaque is modelled as a heterogeneous hyperelastic anisotropic solid composed of the arterial wall, the lipid core and the fibrous cap. Transient velocity and pressure conditions of actual pulsatile blood flow are prescribed. The simulation is achieved using the Arbitrary Lagrangian Eulerian scheme in the COMSOL commercial Finite Element package. The results reveal different types of behavior in function of the length (denoted L) and severity (denoted S) of the stenosis. Whereas large plaques (L>10 mm) are mostly deformed under the action of the blood pressure, it appears that shorter plaques (L<10 mm) are significantly affected by the shear stresses. The shear stresses tend to deform the plaque by pinching it. This effect is called: "the pinching effect". It has an essential influence on the mechanical response of the plaque. For two plaques having the same radius severity S=45%, the maximum stress in the fibrous cap is 50% larger for the short plaque (L=5 mm) than for a larger plaque (L=10 mm), and the maximum wall shear stress is increased by 100%. Provided that they are confirmed by experimental investigations, these results may offer some new perspectives for understanding the vulnerability of short plaques.
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Affiliation(s)
- Tristan Belzacq
- Ecole Nationale Supérieure des Mines, Centre Ingénierie et Santé, CNRS UMR 5146, Saint-Etienne, France
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Creane A, Kelly DJ, Lally C. Patient Specific Computational Modeling in Cardiovascular Mechanics. PATIENT-SPECIFIC COMPUTATIONAL MODELING 2012. [DOI: 10.1007/978-94-007-4552-0_3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
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White SJ, Hayes EM, Lehoux S, Jeremy JY, Horrevoets AJG, Newby AC. Characterization of the differential response of endothelial cells exposed to normal and elevated laminar shear stress. J Cell Physiol 2011; 226:2841-8. [PMID: 21302282 PMCID: PMC3412226 DOI: 10.1002/jcp.22629] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Most acute coronary events occur in the upstream region of stenotic atherosclerotic plaques that experience laminar shear stress (LSS) elevated above normal physiological levels. Many studies have described the atheroprotective effect on endothelial behavior of normal physiological LSS (approximately 15 dynes/cm2) compared to static or oscillatory shear stress (OSS), but it is unknown whether the levels of elevated shear stress imposed by a stenotic plaque would preserve, enhance or reverse this effect. Therefore we used transcriptomics and related functional analyses to compare human endothelial cells exposed to laminar shear stress of 15 (LSS15-normal) or 75 dynes/cm2 (LSS75-elevated). LSS75 upregulated expression of 145 and downregulated expression of 158 genes more than twofold relative to LSS15. Modulation of the metallothioneins (MT1-G, -M, -X) and NADPH oxidase subunits (NOX2, NOX4, NOX5, and p67phox) accompanied suppression of reactive oxygen species production at LSS75. Shear induced changes in dual specificity phosphatases (DUSPs 1, 5, 8, and 16 increasing and DUSPs 6 and 23 decreasing) were observed as well as reduced ERK1/2 but increased p38 MAP kinase phosphorylation. Amongst vasoactive substances, endothelin-1 expression decreased whereas vasoactive intestinal peptide (VIP) and prostacyclin expression increased, despite which intracellular cAMP levels were reduced. Promoter analysis by rVISTA identified a significant over representation of ATF and Nrf2 transcription factor binding sites in genes upregulated by LSS75 compared to LSS15. In summary, LSS75 induced a specific change in behavior, modifying gene expression, reducing ROS levels, altering MAP kinase signaling and reducing cAMP levels, opening multiple avenues for future study. J. Cell. Physiol. 226: 2841–2848, 2011. © 2011 Wiley-Liss, Inc.
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Affiliation(s)
- Stephen J White
- Bristol Heart Institute, University of Bristol (Clinical Sciences South Bristol), Bristol, UK.
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Cummins M, Rossmann JS. Hemodynamics of ulcerated plaques: before and after. J Biomech Eng 2010; 132:104503. [PMID: 20887021 DOI: 10.1115/1.4002372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The hemodynamics and fluid mechanical forces in blood vessels have long been implicated in the deposition and growth of atherosclerotic plaque. Detailed information about the hemodynamics in vessels affected by significant plaque deposits can also provide insight into the mechanisms and likelihood of plaque weakening and rupture. In the current study, the governing equations are solved in their finite volume formulation in several patient-specific stenotic geometries. Of specific interest are the flow patterns and forces near ulcerations in the plaque. The flow patterns and forces in vessels with ulcerated plaques are compared with those in stenotic vessels without evidence of ulceration and to the hemodynamics in the same vessels as they likely appeared prior to ulceration. Hemodynamics "before" and "after" hemorrhage may suggest fluid mechanical and morphological factors of diagnostic and predictive value. Recirculation zones, vortex shedding, and secondary flows are captured by both laminar and turbulent solutions. The forces on vessel walls are shown to correlate with unstable plaque deposits. Performing before and after studies of vessels in long-term radiology studies may illuminate mechanisms of hemorrhage and other vessel remodeling.
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Affiliation(s)
- Megan Cummins
- Department of Biology, Lafayette College, Easton, PA 18042, USA
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