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Manta A, Tzirakis K. A comprehensive review on computational analysis, research advances, and major findings on Abdominal Aortic Aneurysms for the years 2021 to 2023. Ann Vasc Surg 2024:S0890-5096(24)00566-1. [PMID: 39343357 DOI: 10.1016/j.avsg.2024.07.111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2024] [Revised: 06/27/2024] [Accepted: 07/15/2024] [Indexed: 10/01/2024]
Abstract
BACKGROUND Abdominal Aortic Aneurysm (AAA) is a pathological condition characterized by the dilation of the lower part of the aorta, where significant hemodynamic forces are present. The prevalence and high mortality risk associated with AAA remain major concerns within the scientific community. There is a critical need for extensive research to understand the underlying mechanisms, pathophysiological characteristics, and effective detection methods for abdominal aortic abnormalities. Additionally, it is imperative to develop and refine both medical and surgical management strategies. This review aims to indicate the role of computational analysis in the comprehension and management of AAAs and covers recent research studies regarding the computational analysis approach conducted between 2021 and 2023. Computational analysis methods have emerged as sophisticated and non-invasive approaches, providing detailed insights into the complex dynamics of AAA and enhancing our ability to study and manage this condition effectively. METHODS Computational analysis relies on fluid mechanics principles applied to arterial flow, using the Navier-Stokes equations to model blood flow dynamics. Key hemodynamic indicators relevant to AAAs include Time-Average Wall Shear Stress (TAWSS), Oscillatory Shear Index (OSI), Endothelial Cell Activation Potential (ECAP), and Relative Residence Time (RRT). The primary methods employed for simulating the abdominal aorta and studying its biomechanical environment are Computational Fluid Dynamics (CFD) and Finite Element Methods (FEM). This review paper encompasses a thorough examination of recent literature, focusing on studies conducted between 2021 and 2023. RESULTS The latest studies have elucidated crucial insights into the blood flow characteristics and geometric attributes of AAAs. Notably, blood flow patterns within AAAs are associated with increased rupture risk, along with elevated intraluminal thrombus volume and specific calcification thresholds. Asymmetric AAAs exhibit heightened risks of rupture and thrombus formation due to low and oscillating wall shear stresses. Moreover, larger aneurysms demonstrate increased wall stress, pressure, and energy loss. Advanced modeling techniques have augmented predictive capabilities concerning growth rates and surgical thresholds. Additionally, the influence of material properties and thrombus volume on wall stress levels is noteworthy, while inlet velocity profiles significantly modulate blood flow dynamics within AAAs. CONCLUSIONS This review highlights the potential utility of computational modeling. However, the clinical applicability of computational modeling has been limited by methodological variability, despite the ongoing accumulation of evidence supporting the prognostic significance of biomechanical and hemodynamic indices in this field. The establishment of standardized reporting is critical for clinical implementation.
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Affiliation(s)
- Anastasia Manta
- Department of Mechanical Engineering, School of Engineering, Hellenic Mediterranean University, Heraklion, Greece; School of Medicine, University of Crete, Heraklion, Greece.
| | - Konstantinos Tzirakis
- Department of Mechanical Engineering, School of Engineering, Hellenic Mediterranean University, Heraklion, Greece
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Rezaeitaleshmahalleh M, Lyu Z, Mu N, Wang M, Zhang X, Rasmussen TE, McBane Ii RD, Jiang J. Computational Hemodynamics-Based Growth Prediction for Small Abdominal Aortic Aneurysms: Laminar Simulations Versus Large Eddy Simulations. Ann Biomed Eng 2024:10.1007/s10439-024-03572-3. [PMID: 39020077 DOI: 10.1007/s10439-024-03572-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Accepted: 06/27/2024] [Indexed: 07/19/2024]
Abstract
Prior studies have shown that computational fluid dynamics (CFD) simulations help assess patient-specific hemodynamics in abdominal aortic aneurysms (AAAs); patient-specific hemodynamic stressors are frequently used to predict an AAA's growth. Previous studies have utilized both laminar and turbulent simulation models to simulate hemodynamics. However, the impact of different CFD simulation models on the predictive modeling of AAA growth remains unknown and is thus the knowledge gap that motivates this study. Specifically, CFD simulations were performed for 70 AAA models derived from 70 patients' computed tomography angiography (CTA) data with known growth status (i.e., fast-growing [> 5 mm/yr] or slowly growing [< 5 mm/yr]). We used laminar and large eddy simulation (LES) models to obtain hemodynamic parameters to predict AAAs' growth status. Predicting the growth status of AAAs was based on morphological, hemodynamic, and patient health parameters in conjunction with three classical machine learning (ML) classifiers, namely, support vector machine (SVM), K-nearest neighbor (KNN), and generalized linear model (GLM). Our preliminary results estimated aneurysmal flow stability and wall shear stress (WSS) were comparable in both laminar and LES flow simulations. Moreover, computed WSS and velocity-related hemodynamic variables obtained from the laminar and LES simulations showed comparable abilities in differentiating the growth status of AAAs. More importantly, the predictive modeling performance of the three ML classifiers mentioned above was similar, with less than a 2% difference observed (p-value > 0.05). In closing, our findings suggest that two different flow simulations investigated did not significantly affect outcomes of computational hemodynamics and predictive modeling of AAAs' growth status, given the data investigated.
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Affiliation(s)
- Mostafa Rezaeitaleshmahalleh
- Department of Biomedical Engineering, Michigan Technological University, Houghton, MI, USA
- Joint Center for Biocomputing and Digital Health, Health Research Institute, and Institute of Computing and Cybernetics, Michigan Technological University, Houghton, MI, USA
| | - Zonghan Lyu
- Department of Biomedical Engineering, Michigan Technological University, Houghton, MI, USA
- Joint Center for Biocomputing and Digital Health, Health Research Institute, and Institute of Computing and Cybernetics, Michigan Technological University, Houghton, MI, USA
| | - Nan Mu
- Department of Biomedical Engineering, Michigan Technological University, Houghton, MI, USA
- Joint Center for Biocomputing and Digital Health, Health Research Institute, and Institute of Computing and Cybernetics, Michigan Technological University, Houghton, MI, USA
- Sichuan Normal University, Chengdu, Sichuan, China
| | - Min Wang
- Department of Management Science and Statistics, The University of Texas at San Antonio, San Antonino, TX, USA
| | - Xiaoming Zhang
- Department of Radiology, Mayo Clinic, Rochester, MN, 55905, USA
| | - Todd E Rasmussen
- Department of Vascular Surgery, Mayo Clinic, Rochester, MN, 55905, USA
| | | | - Jingfeng Jiang
- Department of Biomedical Engineering, Michigan Technological University, Houghton, MI, USA.
- Joint Center for Biocomputing and Digital Health, Health Research Institute, and Institute of Computing and Cybernetics, Michigan Technological University, Houghton, MI, USA.
- Department of Radiology, Mayo Clinic, Rochester, MN, 55905, USA.
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Balasubramanya A, Maes L, Rega F, Mazzi V, Morbiducci U, Famaey N, Degroote J, Segers P. Hemodynamics and wall shear metrics in a pulmonary autograft: Comparing a fluid-structure interaction and computational fluid dynamics approach. Comput Biol Med 2024; 176:108604. [PMID: 38761502 DOI: 10.1016/j.compbiomed.2024.108604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Revised: 05/02/2024] [Accepted: 05/11/2024] [Indexed: 05/20/2024]
Abstract
OBJECTIVE In young patients, aortic valve disease is often treated by placement of a pulmonary autograft (PA) which adapts to its new environment through growth and remodeling. To better understand the hemodynamic forces acting on the highly distensible PA in the acute phase after surgery, we developed a fluid-structure interaction (FSI) framework and comprehensively compared hemodynamics and wall shear-stress (WSS) metrics with a computational fluid dynamic (CFD) simulation. METHODS The FSI framework couples a prestressed non-linear hyperelastic arterial tissue model with a fluid model using the in-house coupling code CoCoNuT. Geometry, material parameters and boundary conditions are based on in-vivo measurements. Hemodynamics, time-averaged WSS (TAWSS), oscillatory shear index (OSI) and topological shear variation index (TSVI) are evaluated qualitatively and quantitatively for 3 different sheeps. RESULTS Despite systolic-to-diastolic volumetric changes of the PA in the order of 20 %, the point-by-point correlation of TAWSS and OSI obtained through CFD and FSI remains high (r > 0.9, p < 0.01) for TAWSS and (r > 0.8, p < 0.01) for OSI). Instantaneous WSS divergence patterns qualitatively preserve similarities, but large deformations of the PA leads to a decrease of the correlation between FSI and CFD resolved TSVI (r < 0.7, p < 0.01). Moderate co-localization between FSI and CFD is observed for low thresholds of TAWSS and high thresholds of OSI and TSVI. CONCLUSION FSI might be warranted if we were to use the TSVI as a mechano-biological driver for growth and remodeling of PA due to varying intra-vascular flow structures and near wall hemodynamics because of the large expansion of the PA.
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Affiliation(s)
| | - Lauranne Maes
- Department of Mechanical Engineering, KU Leuven, Leuven, Belgium
| | - Filip Rega
- Cardiac Surgery, Department of Cardiovascular Sciences, KU Leuven, Belgium
| | - Valentina Mazzi
- PolitoBIOMed Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy
| | - Umberto Morbiducci
- PolitoBIOMed Lab, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy
| | - Nele Famaey
- Department of Mechanical Engineering, KU Leuven, Leuven, Belgium
| | - Joris Degroote
- Department of Electromechanical Systems and Metal Engineering, Ghent University, Ghent, Belgium
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Natarajan T, Singh-Gryzbon S, Chen H, Sadri V, Ruile P, Neumann FJ, Yoganathan AP, Dasi LP. Sensitivity of Post-TAVR Hemodynamics to the Distal Aortic Arch Anatomy: A High-Fidelity CFD Study. Cardiovasc Eng Technol 2024:10.1007/s13239-024-00728-z. [PMID: 38653932 DOI: 10.1007/s13239-024-00728-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Accepted: 03/22/2024] [Indexed: 04/25/2024]
Abstract
PURPOSE Patient-specific simulations of transcatheter aortic valve (TAV) using computational fluid dynamics (CFD) often rely on assumptions regarding proximal and distal anatomy due to the limited availability of high-resolution imaging away from the TAV site and the primary research focus being near the TAV. However, the influence of these anatomical assumptions on computational efficiency and resulting flow characteristics remains uncertain. This study aimed to investigate the impact of different distal aortic arch anatomies-some of them commonly used in literature-on flow and hemodynamics in the vicinity of the TAV using large eddy simulations (LES). METHODS Three aortic root anatomical configurations with four representative distal aortic arch types were considered in this study. The arch types included a 90-degree bend, an idealized distal aortic arch anatomy, a clipped version of the idealized distal aortic arch, and an anatomy extruded along the normal of segmented anatomical boundary. Hemodynamic parameters both instantaneous and time-averaged such as Wall Shear Stress (WSS), and Oscillatory Shear Index (OSI) were derived and compared from high-fidelity CFD data. RESULTS While there were minor differences in flow and hemodynamics across the configurations examined, they were generally not significant within our region of interest i.e., the aortic root. The choice of extension type had a modest impact on TAV hemodynamics, especially in the vicinity of the TAV with variations observed in local flow patterns and parameters near the TAV. However, these differences were not substantial enough to cause significant deviations in the overall flow and hemodynamic characteristics. CONCLUSIONS The results suggest that under the given configuration and boundary conditions, the type of outflow extension had a modest impact on hemodynamics proximal to the TAV. The findings contribute to a better understanding of flow dynamics in TAV configurations, providing insights for future studies in TAV-related experiments as well as numerical simulations. Additionally, they help mitigate the uncertainties associated with patient-specific geometries, offering increased flexibility in computational modeling.
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Affiliation(s)
- Thangam Natarajan
- Department of Biomedical Engineering, Georgia Institute of Technology, 387 Technology Circle, Atlanta, GA, 30313-2412, USA
| | - Shelly Singh-Gryzbon
- Department of Biomedical Engineering, Georgia Institute of Technology, 387 Technology Circle, Atlanta, GA, 30313-2412, USA
- Department of Chemical Engineering, University of the West Indies, St.Augustine, Trinidad and Tobago
| | - Huang Chen
- Department of Biomedical Engineering, Georgia Institute of Technology, 387 Technology Circle, Atlanta, GA, 30313-2412, USA
| | - Vahid Sadri
- Department of Biomedical Engineering, Georgia Institute of Technology, 387 Technology Circle, Atlanta, GA, 30313-2412, USA
- Abbott Laboratories, 387 Technology Circle, Atlanta, GA, 30313-2412, USA
| | - Philipp Ruile
- Department of Cardiology and Angiology, Medical Center - University of Freiburg, and Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Franz-Josef Neumann
- Department of Cardiology and Angiology, Medical Center - University of Freiburg, and Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Ajit P Yoganathan
- Department of Biomedical Engineering, Georgia Institute of Technology, 387 Technology Circle, Atlanta, GA, 30313-2412, USA
| | - Lakshmi P Dasi
- Department of Biomedical Engineering, Georgia Institute of Technology, 387 Technology Circle, Atlanta, GA, 30313-2412, USA.
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Ali AM, Ghobashy AA, Sultan AA, Elkhodary KI, El-Morsi M. A 3D scaling law for supravalvular aortic stenosis suited for stethoscopic auscultations. Heliyon 2024; 10:e26190. [PMID: 38390109 PMCID: PMC10881376 DOI: 10.1016/j.heliyon.2024.e26190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Revised: 11/24/2023] [Accepted: 02/08/2024] [Indexed: 02/24/2024] Open
Abstract
In this study a frequency scaling law for 3D anatomically representative supravalvular aortic stenosis (SVAS) cases is proposed. The law is uncovered for stethoscopy's preferred auscultation range (70-120 Hz). LES simulations are performed on the CFD solver Fluent, leveraging Simulia's Living Heart Human Model (LHHM), modified to feature hourglass stenoses that range between 30 to 80 percent (mild to severe) in addition to the descending aorta. For physiological hemodynamic boundary conditions the Windkessel model is implemented via a UDF subroutine. The flow-generated acoustic signal is then extracted using the FW-H model and analyzed using FFT. A preferred receiver location that matches clinical practice is confirmed (right intercostal space) and a correlation between the degree of stenosis and a corresponding acoustic frequency is obtained. Five clinical auscultation signals are tested against the scaling law, with the findings interpreted in relation to the NHS classification of stenosis and to the assessments of experienced cardiologists. The scaling law is thus shown to succeed as a potential quantitative decision-support tool for clinicians, enabling them to reliably interpret stethoscopic auscultations for all degrees of stenosis, which is especially useful for moderate degrees of SVAS. Computational investigation of more complex stenotic cases would enhance the clinical relevance of this proposed scaling law, and will be explored in future research.
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Affiliation(s)
- Ahmed M Ali
- Department of Mechanical Engineering, The American University in Cairo, 11835 New Cairo, Egypt
| | - Aly A Ghobashy
- Department of Mechanical Engineering, The American University in Cairo, 11835 New Cairo, Egypt
| | - Abdelrahman A Sultan
- Department of Mechanical Engineering, The American University in Cairo, 11835 New Cairo, Egypt
| | - Khalil I Elkhodary
- Department of Mechanical Engineering, The American University in Cairo, 11835 New Cairo, Egypt
| | - Mohamed El-Morsi
- Department of Mechanical Engineering, The American University in Cairo, 11835 New Cairo, Egypt
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Sawka DM, Su Y, Monteagudo J, Zenit R. Fluid Flow Analysis of Neonatal Dual-Lumen Cannulas for Venovenous Extracorporeal Membrane Oxygenation. J Biomech Eng 2024; 146:021008. [PMID: 38071491 DOI: 10.1115/1.4064212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Indexed: 12/21/2023]
Abstract
Hemolysis persists as a common and serious problem for neonatal patients on extracorporeal membrane oxygenation (ECMO). Since the cannula within the ECMO circuit is associated with hemolysis-inducing shear stresses, real-world internal fluid flow measurements are urgently needed to understand the mechanism and confirm computational estimates. This study appears to be the first experimental study of fluid flow inside commercial ECMO dual-lumen cannulas (DLCs) and first particle image velocimetry (PIV) visualization inside a complicated medical device. The internal geometries of four different opaque neonatal DLCs, both atrial and bicaval positioning geometries each sized 13 Fr and 16 Fr, were replicated by three-dimensional printing clear lumen scaled-up models, which were integrated in a circuit with appropriate ECMO flow parameters. PIV was then used to visualize two-dimensional fluid flow in a single cross section within the models. An empirical model accounting for shear stress and exposure time was used to compare the maximum expected level of hemolysis through each model. The maximum measured peak shear stress recorded was 16±2 Pa in the top arterial bicaval 13 Fr model. The atrial and 16 Fr cannula models never produced greater single-pass peak shear stress or hemolysis than the bicaval and 13 Fr models, respectively, and no difference was found in hemolysis at two different flow rates. After 5 days of flow, small DLC-induced hemolysis values for a single pass through each cannula were modeled to linearly accumulate and caused the most severe hemolysis in the bicaval 13 Fr DLC. Engineering and clinical solutions to improve cannula safety are proposed.
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Affiliation(s)
- Danielle M Sawka
- The Warren Alpert Medical School of Brown University, 70 Ship Street Box G-9486, Providence, RI 02903
| | - Yunxing Su
- Center for Fluid Mechanics, Brown University School of Engineering, 345 Brook St, Providence, RI 02912
| | - Julie Monteagudo
- Pediatric Surgery, The Warren Alpert Medical School of Brown University, 70 Ship Street Box G-M1, Providence, RI 02903
| | - Roberto Zenit
- Center for Fluid Mechanics, Brown University School of Engineering, 345 Brook St, Providence, RI 02912
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Sarantides P, Raptis A, Mathioulakis D, Moulakakis K, Kakisis J, Manopoulos C. Computational Study of Abdominal Aortic Aneurysm Walls Accounting for Patient-Specific Non-Uniform Intraluminal Thrombus Thickness and Distinct Material Models: A Pre- and Post-Rupture Case. Bioengineering (Basel) 2024; 11:144. [PMID: 38391630 PMCID: PMC10886172 DOI: 10.3390/bioengineering11020144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 01/23/2024] [Accepted: 01/26/2024] [Indexed: 02/24/2024] Open
Abstract
An intraluminal thrombus (ILT) is present in the majority of abdominal aortic aneurysms, playing a crucial role in their growth and rupture. Although most computational studies do not include the ILT, in the present study, this is taken into account, laying out the whole simulation procedure, namely, from computed tomography scans to medical image segmentation, geometry reconstruction, mesh generation, biomaterial modeling, finite element analysis, and post-processing, all carried out in open software. By processing the tomography scans of a patient's aneurysm before and after rupture, digital twins are reconstructed assuming a uniform aortic wall thickness. The ILT and the aortic wall are assigned different biomaterial models; namely, the first is modeled as an isotropic linear elastic material, and the second is modeled as the Mooney-Rivlin hyperelastic material as well as the transversely isotropic hyperelastic Holzapfel-Gasser-Ogden nonlinear material. The implementation of the latter requires the designation of local Cartesian coordinate systems in the aortic wall, suitably oriented in space, for the proper orientation of the collagen fibers. The composite aneurysm geometries (ILT and aortic wall structures) are loaded with normal and hypertensive static intraluminal pressure. Based on the calculated stress and strain distributions, ILT seems to be protecting the aneurysm from a structural point of view, as the highest stresses appear in the thrombus-free areas of the aneurysmal wall.
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Affiliation(s)
- Platon Sarantides
- Laboratory of Biofluid Mechanics & Biomedical Technology, School of Mechanical Engineering, National Technical University of Athens, 157 72 Zografos, Greece
| | - Anastasios Raptis
- Laboratory of Biofluid Mechanics & Biomedical Technology, School of Mechanical Engineering, National Technical University of Athens, 157 72 Zografos, Greece
| | - Dimitrios Mathioulakis
- Laboratory of Biofluid Mechanics & Biomedical Technology, School of Mechanical Engineering, National Technical University of Athens, 157 72 Zografos, Greece
- School of Engineering, Bahrain Polytechnic, Isa Town P.O. Box 33349, Bahrain
| | - Konstantinos Moulakakis
- Department of Vascular Surgery, School of Medicine, University of Patras, 265 04 Patras, Greece
| | - John Kakisis
- Department of Vascular Surgery, Attikon University Hospital, National and Kapodistrian University of Athens, 106 79 Athens, Greece
| | - Christos Manopoulos
- Laboratory of Biofluid Mechanics & Biomedical Technology, School of Mechanical Engineering, National Technical University of Athens, 157 72 Zografos, Greece
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Zhang X, Peng Y, Li G, Li J, Luo M, Che Y, Zheng L, Anzai H, Ohta M, Shu C. Elongation of the proximal descending thoracic aorta and associated hemodynamics increase the risk of acute type B aortic dissection. Technol Health Care 2024; 32:765-777. [PMID: 37545271 DOI: 10.3233/thc-230194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/08/2023]
Abstract
BACKGROUND Acute type B aortic dissection (ATBAD) is a life-threatening aortic disease. However, little information is available on predicting and understanding of ATBAD. OBJECTIVE The study sought to explore the underlying mechanism of ATBAD by analyzing the morphological and hemodynamic characteristics related to aortic length. METHODS The length and tortuosity of the segment and the whole aorta in the ATBAD group (n= 163) and control group (n= 120) were measured. A fixed anatomic landmark from the distal of left subclavian artery (LSA) to the superior border of sixth thoracic vertebra was proposed as the proximal descending thoracic aorta (PDTA), and the dimensionless parameter, length ratio, was introduced to eliminate the individual differences. The significant morphological parameters were filtrated and the associations between parameters were investigated using statistical approaches. Furthermore, how aortic morphology influenced ATBAD was explored based on idealized aortic models and hemodynamic-related metrics. RESULTS The PDTA length was significantly increased in the ATBAD group compared with the control group and had a strong positive correlation with the whole aortic length (r= 0.89). The length ratio (LR2) and tortuosity (T2) of PDTA in the ATBAD group were significantly increased (0.15 ± 0.02 vs 0.12 ± 0.02 and 1.73 ± 0.48 vs 1.50 ± 0.36; P< 0.001), and LR2 was positive correlation with T2 (r= 0.73). In receiver-operating curve analysis, the area under the curve was 0.835 for LR2 and 0.641 for T2. Low and oscillatory shear (LOS) was positive correlation with LR2, and the elevated LOS occurred in the distal of LSA. CONCLUSION Elongation of PDTA is associated with ATBAD, and the length ratio is a novel predictor. Elongated PDTA induced more aggressive hemodynamic forces, and high LOS regions may correspond to the entry tear location. The synergy of the morphological variation and aggressive hemodynamics creates contributory conditions for ATBAD.
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Affiliation(s)
- Xuelan Zhang
- School of Mathematics and Physics, University of Science and Technology Beijing, Beijing, China
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, China
| | - Yuan Peng
- Department of Vascular Surgery, Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Gaoyang Li
- Institute of Fluid Science, Tohoku University, Sendai, Japan
| | - Jiehua Li
- Department of Vascular Surgery, Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Mingyao Luo
- Department of Vascular Surgery, Fuwai Hospital, Chinese Academy of Medical Science & Peking Union Medical College, Beijing, China
| | - Yue Che
- School of Mathematics and Physics, University of Science and Technology Beijing, Beijing, China
| | - Liancun Zheng
- School of Mathematics and Physics, University of Science and Technology Beijing, Beijing, China
| | - Hitomi Anzai
- Institute of Fluid Science, Tohoku University, Sendai, Japan
| | - Makoto Ohta
- Institute of Fluid Science, Tohoku University, Sendai, Japan
| | - Chang Shu
- Department of Vascular Surgery, Second Xiangya Hospital, Central South University, Changsha, Hunan, China
- Department of Vascular Surgery, Fuwai Hospital, Chinese Academy of Medical Science & Peking Union Medical College, Beijing, China
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Huang Y, Herbst EB, Xie Y, Yin L, Islam ZH, Kent EW, Wang B, Klibanov AL, Hossack JA. In Vivo Validation of Modulated Acoustic Radiation Force-Based Imaging in Murine Model of Abdominal Aortic Aneurysm Using VEGFR-2-Targeted Microbubbles. Invest Radiol 2023; 58:865-873. [PMID: 37433074 PMCID: PMC10784413 DOI: 10.1097/rli.0000000000001000] [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] [Indexed: 07/13/2023]
Abstract
OBJECTIVES The objective of this study is to validate the modulated acoustic radiation force (mARF)-based imaging method in the detection of abdominal aortic aneurysm (AAA) in murine models using vascular endothelial growth factor receptor 2 (VEGFR-2)-targeted microbubbles (MBs). MATERIALS AND METHODS The mouse AAA model was prepared using the subcutaneous angiotensin II (Ang II) infusion combined with the β-aminopropionitrile monofumarate solution dissolved in drinking water. The ultrasound imaging session was performed at 7 days, 14 days, 21 days, and 28 days after the osmotic pump implantation. For each imaging session, 10 C57BL/6 mice were implanted with Ang II-filled osmotic pumps, and 5 C57BL/6 mice received saline infusion only as the control group. Biotinylated lipid MBs conjugated to either anti-mouse VEGFR-2 antibody (targeted MBs) or isotype control antibody (control MBs) were prepared before each imaging session and were injected into mice via tail vein catheter. Two separate transducers were colocalized to image the AAA and apply ARF to translate MBs simultaneously. After each imaging session, tissue was harvested and the aortas were used for VEGFR-2 immunostaining analysis. From the collected ultrasound image data, the signal magnitude response of the adherent targeted MBs was analyzed, and a parameter, residual-to-saturation ratio ( Rres - sat ), was defined to measure the enhancement in the adherent targeted MBs signal after the cessation of ARF compared with the initial signal intensity. Statistical analysis was performed with the Welch t test and analysis of variance test. RESULTS The Rres - sat of abdominal aortic segments from Ang II-challenged mice was significantly higher compared with that in the saline-infused control group ( P < 0.001) at all 4 time points after osmotic pump implantation (1 week to 4 weeks). In control mice, the Rres - sat values were 2.13%, 1.85%, 3.26%, and 4.85% at 1, 2, 3, and 4 weeks postimplantation, respectively. In stark contrast, the Rres - sat values for the mice with Ang II-induced AAA lesions were 9.20%, 20.6%, 22.7%, and 31.8%, respectively. It is worth noting that there was a significant difference between the Rres - sat for Ang II-infused mice at all 4 time points ( P < 0.005), a finding not present in the saline-infused mice. Immunostaining results revealed the VEGFR-2 expression was increased in the abdominal aortic segments of Ang II-infused mice compared with the control group. CONCLUSIONS The mARF-based imaging technique was validated in vivo using a murine model of AAA and VEGFR-2-targeted MBs. Results in this study indicated that the mARF-based imaging technique has the ability to detect and assess AAA growth at early stages based on the signal intensity of adherent targeted MBs, which is correlated with the expression level of the desired molecular biomarker. The results may suggest, in very long term, a pathway toward eventual clinical implementation for an ultrasound molecular imaging-based approach to AAA risk assessment in asymptomatic patients.
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Affiliation(s)
- Yi Huang
- From the Department of Biomedical Engineering, University of Virginia, Charlottesville, VA (Y.H., Y.X., J.A.H.); Philips Research North America, Cambridge, MA (E.B.H.); Department of Surgery, School of Medicine, University of Virginia, Charlottesville, VA (L.Y., Z.H.I., E.W.K., B.W.); and Division of Cardiovascular Medicine, Cardiovascular Research Center and Department of Biomedical Engineering, University of Virginia, Charlottesville, VA (A.L.K.)
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Zhang X, Mao B, Che Y, Kang J, Luo M, Qiao A, Liu Y, Anzai H, Ohta M, Guo Y, Li G. Physics-informed neural networks (PINNs) for 4D hemodynamics prediction: An investigation of optimal framework based on vascular morphology. Comput Biol Med 2023; 164:107287. [PMID: 37536096 DOI: 10.1016/j.compbiomed.2023.107287] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Revised: 07/06/2023] [Accepted: 07/28/2023] [Indexed: 08/05/2023]
Abstract
Hemodynamic parameters are of great significance in the clinical diagnosis and treatment of cardiovascular diseases. However, noninvasive, real-time and accurate acquisition of hemodynamics remains a challenge for current invasive detection and simulation algorithms. Here, we integrate computational fluid dynamics with our customized analysis framework based on a multi-attribute point cloud dataset and physics-informed neural networks (PINNs)-aided deep learning modules. This combination is implemented by our workflow that generates flow field datasets within two types of patient personalized models - aorta with fine coronary branches and abdominal aorta. Deep learning modules with or without an antecedent hierarchical structure model the flow field development and complete the mapping from spatial and temporal dimensions to 4D hemodynamics. 88,000 cases on 4 randomized partitions in 16 controlled trials reveal the hemodynamic landscape of spatio-temporal anisotropy within two types of personalized models, which demonstrates the effectiveness of PINN in predicting the space-time behavior of flow fields and gives the optimal deep learning framework for different blood vessels in terms of balancing the training cost and accuracy dimensions. The proposed framework shows intentional performance in computational cost, accuracy and visualization compared to currently prevalent methods, and has the potential for generalization to model flow fields and corresponding clinical metrics within vessels at different locations. We expect our framework to push the 4D hemodynamic predictions to the real-time level, and in statistically significant fashion, applicable to morphologically variable vessels.
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Affiliation(s)
- Xuelan Zhang
- School of Mathematics and Physics, University of Science and Technology Beijing, Beijing, 100083, China
| | - Baoyan Mao
- Beijing University of Chinese Medicine, Beijing 100029, China
| | - Yue Che
- School of Mathematics and Physics, University of Science and Technology Beijing, Beijing, 100083, China
| | - Jiaheng Kang
- School of Mathematics and Physics, University of Science and Technology Beijing, Beijing, 100083, China
| | - Mingyao Luo
- Department of Vascular Surgery, Fuwai Hospital, Chinese Academy of Medical Science & Peking Union Medical College, Beijing, 100037, China; Department of Vascular Surgery, Fuwai Yunnan Cardiovascular Hospital, Affiliated Cardiovascular Hospital of Kunming Medical University, Kunming, 650102, China
| | - Aike Qiao
- Faculty of Environment and Life, Beijing University of Technology, Beijing, China
| | - Youjun Liu
- Faculty of Environment and Life, Beijing University of Technology, Beijing, China
| | - Hitomi Anzai
- Institute of Fluid Science, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, 980-8577, Japan
| | - Makoto Ohta
- Institute of Fluid Science, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, 980-8577, Japan
| | - Yuting Guo
- Department of Mechanical Engineering and Science, Kyoto University, Kyoto, 615-8540, Japan
| | - Gaoyang Li
- Institute of Fluid Science, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, 980-8577, Japan.
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11
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Spartera M, Stracquadanio A, Pessoa-Amorim G, Harston G, Mazzucco S, Young V, Von Ende A, Hess AT, Ferreira VM, Kennedy J, Neubauer S, Casadei B, Wijesurendra RS. Reduced Left Atrial Rotational Flow Is Independently Associated With Embolic Brain Infarcts. JACC Cardiovasc Imaging 2023; 16:1149-1159. [PMID: 37204381 DOI: 10.1016/j.jcmg.2023.03.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 02/22/2023] [Accepted: 03/10/2023] [Indexed: 05/20/2023]
Abstract
BACKGROUND Up to 25% of embolic strokes occur in individuals without atrial fibrillation (AF) or other identifiable mechanisms. OBJECTIVES This study aims to assess whether left atrial (LA) blood flow characteristics are associated with embolic brain infarcts, independently of AF. METHODS The authors recruited 134 patients: 44 with a history of ischemic stroke and 90 with no history of stroke but CHA2DS2VASc score ≥1. Cardiac magnetic resonance (CMR) evaluated cardiac function and LA 4-dimensional flow parameters, including velocity and vorticity (a measure of rotational flow), and brain magnetic resonance imaging (MRI) was performed to detect large noncortical or cortical infarcts (LNCCIs) (likely embolic), or nonembolic lacunar infarcts. RESULTS Patients (41% female; age 70 ± 9 years) had moderate stroke risk (median CHA2DS2VASc = 3, Q1-Q3: 2-4). Sixty-eight (51%) had diagnosed AF, of whom 58 (43%) were in AF during CMR. Thirty-nine (29%) had ≥1 LNCCI, 20 (15%) had ≥1 lacunar infarct without LNCCI, and 75 (56%) had no infarct. Lower LA vorticity was significantly associated with prevalent LNCCIs after adjustment for AF during CMR, history of AF, CHA2DS2VASc score, LA emptying fraction, LA indexed maximum volume, left ventricular ejection fraction, and indexed left ventricular mass (OR: 2.06 [95% CI: 1.08-3.92 per SD]; P = 0.027). By contrast, LA flow peak velocity was not significantly associated with LNCCIs (P = 0.21). No LA parameter was associated with lacunar infarcts (all P > 0.05). CONCLUSIONS Reduced LA flow vorticity is significantly and independently associated with embolic brain infarcts. Imaging LA flow characteristics may aid identification of individuals who would benefit from anticoagulation for embolic stroke prevention, regardless of heart rhythm.
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Affiliation(s)
- Marco Spartera
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom; University of Oxford Centre for Clinical Magnetic Resonance Research, Oxford, United Kingdom; Oxford University Hospital NHS Foundation Trust, Oxford, United Kingdom.
| | - Antonio Stracquadanio
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom; University of Oxford Centre for Clinical Magnetic Resonance Research, Oxford, United Kingdom; Oxford University Hospital NHS Foundation Trust, Oxford, United Kingdom
| | - Guilherme Pessoa-Amorim
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom; University of Oxford Centre for Clinical Magnetic Resonance Research, Oxford, United Kingdom; Oxford University Hospital NHS Foundation Trust, Oxford, United Kingdom; CTSU Nuffield Department of Population Health, University of Oxford, Oxford, United Kingdom
| | - George Harston
- Oxford University Hospital NHS Foundation Trust, Oxford, United Kingdom
| | - Sara Mazzucco
- Oxford University Hospital NHS Foundation Trust, Oxford, United Kingdom; Wolfson Centre for Prevention of Stroke and Dementia, Nuffield Department of Clinical Neuroscience, Oxford, United Kingdom
| | - Victoria Young
- Oxford University Hospital NHS Foundation Trust, Oxford, United Kingdom
| | - Adam Von Ende
- CTSU Nuffield Department of Population Health, University of Oxford, Oxford, United Kingdom
| | - Aaron T Hess
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom; University of Oxford Centre for Clinical Magnetic Resonance Research, Oxford, United Kingdom
| | - Vanessa M Ferreira
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom; University of Oxford Centre for Clinical Magnetic Resonance Research, Oxford, United Kingdom; Oxford University Hospital NHS Foundation Trust, Oxford, United Kingdom
| | - James Kennedy
- Oxford University Hospital NHS Foundation Trust, Oxford, United Kingdom
| | - Stefan Neubauer
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom; University of Oxford Centre for Clinical Magnetic Resonance Research, Oxford, United Kingdom; Oxford University Hospital NHS Foundation Trust, Oxford, United Kingdom
| | - Barbara Casadei
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom; Oxford University Hospital NHS Foundation Trust, Oxford, United Kingdom
| | - Rohan S Wijesurendra
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom; University of Oxford Centre for Clinical Magnetic Resonance Research, Oxford, United Kingdom; Oxford University Hospital NHS Foundation Trust, Oxford, United Kingdom; CTSU Nuffield Department of Population Health, University of Oxford, Oxford, United Kingdom
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12
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Rezaeitaleshmahalleh M, Lyu Z, Mu N, Zhang X, Rasmussen TE, McBane RD, Jiang J. Characterization of small abdominal aortic aneurysms' growth status using spatial pattern analysis of aneurismal hemodynamics. Sci Rep 2023; 13:13832. [PMID: 37620387 PMCID: PMC10449842 DOI: 10.1038/s41598-023-40139-z] [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: 05/26/2023] [Accepted: 08/05/2023] [Indexed: 08/26/2023] Open
Abstract
Aneurysm hemodynamics is known for its crucial role in the natural history of abdominal aortic aneurysms (AAA). However, there is a lack of well-developed quantitative assessments for disturbed aneurysmal flow. Therefore, we aimed to develop innovative metrics for quantifying disturbed aneurysm hemodynamics and evaluate their effectiveness in predicting the growth status of AAAs, specifically distinguishing between fast-growing and slowly-growing aneurysms. The growth status of aneurysms was classified as fast (≥ 5 mm/year) or slow (< 5 mm/year) based on serial imaging over time. We conducted computational fluid dynamics (CFD) simulations on 70 patients with computed tomography (CT) angiography findings. By converting hemodynamics data (wall shear stress and velocity) located on unstructured meshes into image-like data, we enabled spatial pattern analysis using Radiomics methods, referred to as "Hemodynamics-informatics" (i.e., using informatics techniques to analyze hemodynamic data). Our best model achieved an AUROC of 0.93 and an accuracy of 87.83%, correctly identifying 82.00% of fast-growing and 90.75% of slowly-growing AAAs. Compared with six classification methods, the models incorporating hemodynamics-informatics exhibited an average improvement of 8.40% in AUROC and 7.95% in total accuracy. These preliminary results indicate that hemodynamics-informatics correlates with AAAs' growth status and aids in assessing their progression.
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Affiliation(s)
- Mostafa Rezaeitaleshmahalleh
- Department of Biomedical Engineering, Michigan Technological University, Houghton, MI, USA
- Joint Center for Biocomputing and Digital Health, Health Research Institute, and Institute of Computing and Cybernetics, Michigan Technological University, Houghton, MI, USA
| | - Zonghan Lyu
- Department of Biomedical Engineering, Michigan Technological University, Houghton, MI, USA
- Joint Center for Biocomputing and Digital Health, Health Research Institute, and Institute of Computing and Cybernetics, Michigan Technological University, Houghton, MI, USA
| | - Nan Mu
- Department of Biomedical Engineering, Michigan Technological University, Houghton, MI, USA
- Joint Center for Biocomputing and Digital Health, Health Research Institute, and Institute of Computing and Cybernetics, Michigan Technological University, Houghton, MI, USA
| | - Xiaoming Zhang
- Department of Radiology, Mayo Clinic, Rochester, MN, USA
| | - Todd E Rasmussen
- Division of Vascular and Endovascular Surgery, Mayo Clinic, Rochester, MN, USA
| | - Robert D McBane
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN, USA
| | - Jingfeng Jiang
- Department of Biomedical Engineering, Michigan Technological University, Houghton, MI, USA.
- Joint Center for Biocomputing and Digital Health, Health Research Institute, and Institute of Computing and Cybernetics, Michigan Technological University, Houghton, MI, USA.
- Department of Radiology, Mayo Clinic, Rochester, MN, USA.
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13
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Wang X, Carpenter HJ, Ghayesh MH, Kotousov A, Zander AC, Amabili M, Psaltis PJ. A review on the biomechanical behaviour of the aorta. J Mech Behav Biomed Mater 2023; 144:105922. [PMID: 37320894 DOI: 10.1016/j.jmbbm.2023.105922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 05/14/2023] [Accepted: 05/20/2023] [Indexed: 06/17/2023]
Abstract
Large aortic aneurysm and acute and chronic aortic dissection are pathologies of the aorta requiring surgery. Recent advances in medical intervention have improved patient outcomes; however, a clear understanding of the mechanisms leading to aortic failure and, hence, a better understanding of failure risk, is still missing. Biomechanical analysis of the aorta could provide insights into the development and progression of aortic abnormalities, giving clinicians a powerful tool in risk stratification. The complexity of the aortic system presents significant challenges for a biomechanical study and requires various approaches to analyse the aorta. To address this, here we present a holistic review of the biomechanical studies of the aorta by categorising articles into four broad approaches, namely theoretical, in vivo, experimental and combined investigations. Experimental studies that focus on identifying mechanical properties of the aortic tissue are also included. By reviewing the literature and discussing drawbacks, limitations and future challenges in each area, we hope to present a more complete picture of the state-of-the-art of aortic biomechanics to stimulate research on critical topics. Combining experimental modalities and computational approaches could lead to more comprehensive results in risk prediction for the aortic system.
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Affiliation(s)
- Xiaochen Wang
- School of Electrical and Mechanical Engineering, The University of Adelaide, Adelaide, South Australia 5005, Australia.
| | - Harry J Carpenter
- School of Electrical and Mechanical Engineering, The University of Adelaide, Adelaide, South Australia 5005, Australia
| | - Mergen H Ghayesh
- School of Electrical and Mechanical Engineering, The University of Adelaide, Adelaide, South Australia 5005, Australia.
| | - Andrei Kotousov
- School of Electrical and Mechanical Engineering, The University of Adelaide, Adelaide, South Australia 5005, Australia
| | - Anthony C Zander
- School of Electrical and Mechanical Engineering, The University of Adelaide, Adelaide, South Australia 5005, Australia
| | - Marco Amabili
- Department of Mechanical Engineering, McGill University, Montreal H3A 0C3, Canada
| | - Peter J Psaltis
- Adelaide Medical School, The University of Adelaide, Adelaide, South Australia 5005, Australia; Department of Cardiology, Central Adelaide Local Health Network, Adelaide, South Australia 5000, Australia; Vascular Research Centre, Heart Health Theme, South Australian Health & Medical Research Institute (SAHMRI), Adelaide, South Australia 5000, Australia
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14
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Wang X, Ghayesh MH, Kotousov A, Zander AC, Dawson JA, Psaltis PJ. Fluid-structure interaction study for biomechanics and risk factors in Stanford type A aortic dissection. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2023:e3736. [PMID: 37258411 DOI: 10.1002/cnm.3736] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 04/04/2023] [Accepted: 05/16/2023] [Indexed: 06/02/2023]
Abstract
Aortic dissection is a life-threatening condition with a rising prevalence in the elderly population, possibly as a consequence of the increasing population life expectancy. Untreated aortic dissection can lead to myocardial infarction, aortic branch malperfusion or occlusion, rupture, aneurysm formation and death. This study aims to assess the potential of a biomechanical model in predicting the risks of a non-dilated thoracic aorta with Stanford type A dissection. To achieve this, a fully coupled fluid-structure interaction model was developed under realistic blood flow conditions. This model of the aorta was developed by considering three-dimensional artery geometry, multiple artery layers, hyperelastic artery wall, in vivo-based physiological time-varying blood velocity profiles, and non-Newtonian blood behaviours. The results demonstrate that in a thoracic aorta with Stanford type A dissection, the wall shear stress (WSS) is significantly low in the ascending aorta and false lumen, leading to potential aortic dilation and thrombus formation. The results also reveal that the WSS is highly related to blood flow patterns. The aortic arch region near the brachiocephalic and left common carotid artery is prone to rupture, showing a good agreement with the clinical reports. The results have been translated into their potential clinical relevance by revealing the role of the stress state, WSS and flow characteristics as the main parameters affecting lesion progression, including rupture and aneurysm. The developed model can be tailored for patient-specific studies and utilised as a predictive tool to estimate aneurysm growth and initiation of wall rupture inside the human thoracic aorta.
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Affiliation(s)
- Xiaochen Wang
- School of Mechanical Engineering, University of Adelaide, Adelaide, Australia
| | - Mergen H Ghayesh
- School of Mechanical Engineering, University of Adelaide, Adelaide, Australia
| | - Andrei Kotousov
- School of Mechanical Engineering, University of Adelaide, Adelaide, Australia
| | - Anthony C Zander
- School of Mechanical Engineering, University of Adelaide, Adelaide, Australia
| | - Joseph A Dawson
- Department of Vascular & Endovascular Surgery, Royal Adelaide Hospital, Adelaide, Australia
- Trauma Surgery Unit, Royal Adelaide Hospital, Adelaide, Australia
- Adelaide Medical School, University of Adelaide, Adelaide, Australia
| | - Peter J Psaltis
- Adelaide Medical School, University of Adelaide, Adelaide, Australia
- Vascular Research Centre, Lifelong Health Theme, South Australian Health & Medical Research Institute (SAHMRI), Adelaide, Australia
- Department of Cardiology, Central Adelaide Local Health Network, Adelaide, Australia
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15
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Bontekoe J, Matsumura J, Liu B. Thrombosis in the pathogenesis of abdominal aortic aneurysm. JVS Vasc Sci 2023; 4:100106. [PMID: 37564632 PMCID: PMC10410173 DOI: 10.1016/j.jvssci.2023.100106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Accepted: 03/23/2023] [Indexed: 08/12/2023] Open
Abstract
Background Abdominal aortic aneurysms (AAAs) are a relatively common vascular pathology of the elderly with high morbidity potential. Irreversible degeneration of the aortic wall leads to lethal rupture if left untreated. Nearly all AAAs contain intraluminal thrombus (ILT) to a varying degree, yet the mechanisms explaining how thrombosis is disturbed in AAA are relatively unknown. This review examined the thrombotic complications associated with AAA, the impact of thrombosis on AAA surgical outcomes and AAA pathogenesis, and the use of antithrombotic therapy in the management of this disease. Methods A literature search of the PubMed database was conducted using relevant keywords related to thrombosis and AAAs. Results Thrombotic complications are relatively infrequent in AAA yet carry significant morbidity risks. The ILT can impact endovascular aneurysm repair by limiting anatomic suitability and influence the risk of endoleaks. Many of the pathologic mechanisms involved in AAA development, including hemodynamics, inflammation, oxidative stress, and aortic wall remodeling, contain pathways that interact with thrombosis. Conversely, the ILT can also be a source of biochemical stress and exacerbate these aneurysmal processes. In animal AAA models, antithrombotic therapies have shown favorable results in preventing and stabilizing AAA. Antiplatelet agents may be beneficial for reducing risks of major adverse cardiovascular events in AAA patients; however, neither antiplatelet nor anticoagulation is currently used solely for the management of AAA. Conclusions Thrombosis and ILT may have detrimental effects on AAA growth, rupture risk, and patient outcomes, yet there is limited understanding of the pathologic thrombotic mechanisms in aneurysmal disease at the molecular level. Preventing ILT using platelet and coagulation inhibitors may be a reasonable theoretical target for aneurysm progression and stability; however, the practical benefits of current antithrombotic therapies in AAA are unclear. Further research is needed to demonstrate the extent to which thrombosis impacts AAA pathogenesis and to develop novel pharmacologic strategies for the medical management of this disease.
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Affiliation(s)
- Jack Bontekoe
- Division of Vascular Surgery, Department of Surgery, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI
| | - Jon Matsumura
- Division of Vascular Surgery, Department of Surgery, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI
| | - Bo Liu
- Division of Vascular Surgery, Department of Surgery, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI
- Department of Cellular and Regenerative Biology, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI
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16
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Gasser TC, Miller C, Polzer S, Roy J. A quarter of a century biomechanical rupture risk assessment of abdominal aortic aneurysms. Achievements, clinical relevance, and ongoing developments. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2023; 39:e3587. [PMID: 35347895 DOI: 10.1002/cnm.3587] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 01/28/2022] [Accepted: 03/03/2022] [Indexed: 05/12/2023]
Abstract
Abdominal aortic aneurysm (AAA) disease, the local enlargement of the infrarenal aorta, is a serious condition that causes many deaths, especially in men exceeding 65 years of age. Over the past quarter of a century, computational biomechanical models have been developed towards the assessment of AAA risk of rupture, technology that is now on the verge of being integrated within the clinical decision-making process. The modeling of AAA requires a holistic understanding of the clinical problem, in order to set appropriate modeling assumptions and to draw sound conclusions from the simulation results. In this article we summarize and critically discuss the proposed modeling approaches and report the outcome of clinical validation studies for a number of biomechanics-based rupture risk indices. Whilst most of the aspects concerning computational mechanics have already been settled, it is the exploration of the failure properties of the AAA wall and the acquisition of robust input data for simulations that has the greatest potential for the further improvement of this technology.
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Affiliation(s)
- T Christian Gasser
- Department of Engineering Mechanics, KTH Royal Institute of Technology, Stockholm, Sweden
- Faculty of Health Sciences, University of Southern Denmark, Odense, Denmark
| | - Christopher Miller
- Department of Engineering Mechanics, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Stanislav Polzer
- Department of Applied Mechanics, VSB-Technical University of Ostrava, Ostrava-Poruba, Czech Republic
| | - Joy Roy
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
- Department of Vascular Surgery, Karolinska University Hospital, Stockholm, Sweden
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17
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Aggarwal A, Jennings CL, Manning E, Cameron SJ. Platelets at the Vessel Wall in Non-Thrombotic Disease. Circ Res 2023; 132:775-790. [PMID: 36927182 PMCID: PMC10027394 DOI: 10.1161/circresaha.122.321566] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Accepted: 02/15/2023] [Indexed: 03/18/2023]
Abstract
Platelets are small, anucleate entities that bud from megakaryocytes in the bone marrow. Among circulating cells, platelets are the most abundant cell, traditionally involved in regulating the balance between thrombosis (the terminal event of platelet activation) and hemostasis (a protective response to tissue injury). Although platelets lack the precise cellular control offered by nucleate cells, they are in fact very dynamic cells, enriched in preformed RNA that allows them the capability of de novo protein synthesis which alters the platelet phenotype and responses in physiological and pathological events. Antiplatelet medications have significantly reduced the morbidity and mortality for patients afflicted with thrombotic diseases, including stroke and myocardial infarction. However, it has become apparent in the last few years that platelets play a critical role beyond thrombosis and hemostasis. For example, platelet-derived proteins by constitutive and regulated exocytosis can be found in the plasma and may educate distant tissue including blood vessels. First, platelets are enriched in inflammatory and anti-inflammatory molecules that may regulate vascular remodeling. Second, platelet-derived microparticles released into the circulation can be acquired by vascular endothelial cells through the process of endocytosis. Third, platelets are highly enriched in mitochondria that may contribute to the local reactive oxygen species pool and remodel phospholipids in the plasma membrane of blood vessels. Lastly, platelets are enriched in proteins and phosphoproteins which can be secreted independent of stimulation by surface receptor agonists in conditions of disturbed blood flow. This so-called biomechanical platelet activation occurs in regions of pathologically narrowed (atherosclerotic) or dilated (aneurysmal) vessels. Emerging evidence suggests platelets may regulate the process of angiogenesis and blood flow to tumors as well as education of distant organs for the purposes of allograft health following transplantation. This review will illustrate the potential of platelets to remodel blood vessels in various diseases with a focus on the aforementioned mechanisms.
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Affiliation(s)
- Anu Aggarwal
- Department of Cardiovascular and Metabolic Sciences, Lerner Research Institute, Cleveland, Ohio
| | - Courtney L. Jennings
- Department of Cardiovascular and Metabolic Sciences, Lerner Research Institute, Cleveland, Ohio
| | - Emily Manning
- Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Scott J. Cameron
- Department of Cardiovascular and Metabolic Sciences, Lerner Research Institute, Cleveland, Ohio
- Heart Vascular and Thoracic Institute, Department of Cardiovascular Medicine, Section of Vascular Medicine, Cleveland Clinic Foundation, Cleveland, Ohio, USA
- Case Western Reserve University School of Medicine, Cleveland, Ohio
- Department of Hematology, Taussig Cancer Center, Cleveland, Ohio
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18
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Classification of Blood Rheological Models through an Idealized Symmetrical Bifurcation. Symmetry (Basel) 2023. [DOI: 10.3390/sym15030630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/06/2023] Open
Abstract
The assumed rheological behavior of blood influences the hemodynamic characteristics of numerical blood flow simulations. Until now, alternative rheological specifications have been utilized, with uncertain implications for the results obtained. This work aims to group sixteen blood rheological models in homogeneous clusters, by exploiting data generated from numerical simulations on an idealized symmetrical arterial bifurcation. Blood flow is assumed to be pulsatile and is simulated using a commercial finite volume solver. An appropriate mesh convergence study is performed, and all results are collected at three different time instants throughout the cardiac cycle: at peak systole, early diastole, and late diastole. Six hemodynamic variables are computed: the time average wall shear stress, oscillatory shear index, relative residence time, global and local non-Newtonian importance factor, and non-Newtonian effect factor. The resulting data are analyzed using hierarchical agglomerative clustering algorithms, which constitute typical unsupervised classification methods. Interestingly, the rheological models can be partitioned into three homogeneous groups, whereas three specifications appear as outliers which do not belong in any partition. Our findings suggest that models which are defined in a similar manner from a mathematical perspective may behave substantially differently in terms of the data they produce. On the other hand, models characterized by different mathematical formulations may belong to the same statistical group (cluster) and can thus be considered interchangeably.
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19
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Mutlu O, Salman HE, Al-Thani H, El-Menyar A, Qidwai UA, Yalcin HC. How does hemodynamics affect rupture tissue mechanics in abdominal aortic aneurysm: Focus on wall shear stress derived parameters, time-averaged wall shear stress, oscillatory shear index, endothelial cell activation potential, and relative residence time. Comput Biol Med 2023; 154:106609. [PMID: 36724610 DOI: 10.1016/j.compbiomed.2023.106609] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Revised: 01/19/2023] [Accepted: 01/22/2023] [Indexed: 01/24/2023]
Abstract
An abdominal aortic aneurysm (AAA) is a critical health condition with a risk of rupture, where the diameter of the aorta enlarges more than 50% of its normal diameter. The incidence rate of AAA has increased worldwide. Currently, about three out of every 100,000 people have aortic diseases. The diameter and geometry of AAAs influence the hemodynamic forces exerted on the arterial wall. Therefore, a reliable assessment of hemodynamics is crucial for predicting the rupture risk. Wall shear stress (WSS) is an important metric to define the level of the frictional force on the AAA wall. Excessive levels of WSS deteriorate the remodeling mechanism of the arteries and lead to abnormal conditions. At this point, WSS-related hemodynamic parameters, such as time-averaged WSS (TAWSS), oscillatory shear index (OSI), endothelial cell activation potential (ECAP), and relative residence time (RRT) provide important information to evaluate the shear environment on the AAA wall in detail. Calculation of these parameters is not straightforward and requires a physical understanding of what they represent. In addition, computational fluid dynamics (CFD) solvers do not readily calculate these parameters when hemodynamics is simulated. This review aims to explain the WSS-derived parameters focusing on how these represent different characteristics of disturbed hemodynamics. A representative case is presented for spatial and temporal formulation that would be useful for interested researchers for practical calculations. Finally, recent hemodynamics investigations relating WSS-related parameters with AAA rupture risk assessment are presented. This review will be useful to understand the physical representation of WSS-related parameters in cardiovascular flows and how they can be calculated practically for AAA investigations.
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Affiliation(s)
- Onur Mutlu
- Biomedical Research Center, Qatar University, Doha, Qatar
| | - Huseyin Enes Salman
- Department of Mechanical Engineering, TOBB University of Economics and Technology, Ankara, Turkey
| | - Hassan Al-Thani
- Department of Surgery, Trauma and Vascular Surgery, Hamad General Hospital, Hamad Medical Corporation, P.O. Box 3050, Doha, Qatar
| | - Ayman El-Menyar
- Department of Surgery, Trauma and Vascular Surgery, Hamad General Hospital, Hamad Medical Corporation, P.O. Box 3050, Doha, Qatar; Clinical Medicine, Weill Cornell Medical College, Doha, Qatar
| | - Uvais Ahmed Qidwai
- Department of Computer Science Engineering, Qatar University, Doha, Qatar
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20
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Nakayama K, Furuyama T, Matsubara Y, Morisaki K, Onohara T, Ikeda T, Yoshizumi T. Gut dysbiosis and bacterial translocation in the aneurysmal wall and blood in patients with abdominal aortic aneurysm. PLoS One 2022; 17:e0278995. [PMID: 36516156 PMCID: PMC9749999 DOI: 10.1371/journal.pone.0278995] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Accepted: 11/28/2022] [Indexed: 12/15/2022] Open
Abstract
Inflammation plays a part in the development of abdominal aortic aneurysm (AAA), and the gut microbiota affects host inflammation by bacterial translocation. The relationship between abdominal aortic aneurysm and the gut microbiota remains unknown. This study aimed to detect bacterial translocation in the aneurysmal wall and blood of patients with abdominal aortic aneurysm, and to investigate the effect of the gut microbiota on abdominal aortic aneurysm. We investigated 30 patients with abdominal aortic aneurysm from 2017 to 2019. We analysed the aneurysmal wall and blood using highly sensitive reverse transcription-quantitative polymerase chain reaction, and the gut microbiota was investigated using next-generation sequencing. In the 30 patients, bacteria were detected by reverse transcription- quantitative polymerase chain reaction in 19 blood samples (detection rate, 63%) and in 11 aneurysmal wall samples (detection rate, 37%). In the gut microbiota analysis, the Firmicutes/Bacteroidetes ratio was increased. The neutrophil-lymphocyte ratio was higher (2.94 ± 1.77 vs 1.96 ± 0.61, P < 0.05) and the lymphocyte-monocyte ratio was lower (4.02 ± 1.25 vs 5.86 ± 1.38, P < 0.01) in the bacterial carrier group than in the bacterial non-carrier group in blood samples. The volume of intraluminal thrombus was significantly higher in the bacterial carrier group than in the bacterial non-carrier group in aneurysmal wall samples (64.0% vs 34.7%, P < 0.05). We confirmed gut dysbiosis and bacterial translocation to the blood and aneurysmal wall in patients with abdominal aortic aneurysm. There appears to be a relationship between the gut microbiota and abdominal aortic aneurysm.
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Affiliation(s)
- Ken Nakayama
- Department of Surgery and Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Tadashi Furuyama
- Department of Surgery and Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
- * E-mail:
| | - Yutaka Matsubara
- Department of Surgery and Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Koichi Morisaki
- Department of Surgery and Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Toshihiro Onohara
- Department of Vascular Surgery, National Hospital Organization Kyushu Medical Center, Fukuoka, Japan
| | - Tetsuo Ikeda
- Department of Surgery and Endoscope Center, Oral Medicine Research Center, Fukuoka Dental College, Fukuoka, Japan
| | - Tomoharu Yoshizumi
- Department of Surgery and Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
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21
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Zhang J, Rothenberger SM, Brindise MC, Markl M, Rayz VL, Vlachos PP. Wall Shear Stress Estimation for 4D Flow MRI Using Navier-Stokes Equation Correction. Ann Biomed Eng 2022; 50:1810-1825. [PMID: 35943617 PMCID: PMC10263099 DOI: 10.1007/s10439-022-02993-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Accepted: 06/09/2022] [Indexed: 12/30/2022]
Abstract
This study introduces a novel wall shear stress (WSS) estimation method for 4D flow MRI. The method improves the WSS accuracy by using the reconstructed pressure gradient and the flow-physics constraints to correct velocity gradient estimation. The method was tested on synthetic 4D flow data of analytical Womersley flow and flow in cerebral aneurysms and applied to in vivo 4D flow data acquired in cerebral aneurysms and aortas. The proposed method's performance was compared to the state-of-the-art method based on smooth-spline fitting of velocity profile and the WSS calculated from uncorrected velocity gradient. The proposed method improved the WSS accuracy by as much as 100% for the Womersley flow and reduced the underestimation of mean WSS by 39 to 50% for the synthetic aneurysmal flow. The predicted mean WSS from the in vivo aneurysmal data using the proposed method was 31 to 50% higher than the other methods. The predicted aortic WSS using the proposed method was 3 to 6 times higher than the other methods and was consistent with previous CFD studies and the results from recently developed methods that take into account the limited spatial resolution of 4D flow MRI. The proposed method improves the accuracy of WSS estimation from 4D flow MRI, which can help predict blood vessel remodeling and progression of cardiovascular diseases.
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Affiliation(s)
- Jiacheng Zhang
- School of Mechanical Engineering, Purdue University, West Lafayette, IN, 47907, USA
| | - Sean M Rothenberger
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, 47907, USA
| | - Melissa C Brindise
- Department of Mechanical Engineering, Pennsylvania State University, University Park, PA, 16802, USA
| | - Michael Markl
- Feinberg School of Medicine, Northwestern University, Chicago, IL, 60611, USA
- McCormick School of Engineering, Northwestern University, Evanston, IL, 60208, USA
| | - Vitaliy L Rayz
- School of Mechanical Engineering, Purdue University, West Lafayette, IN, 47907, USA
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, 47907, USA
| | - Pavlos P Vlachos
- School of Mechanical Engineering, Purdue University, West Lafayette, IN, 47907, USA.
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, 47907, USA.
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22
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Lynch S, Nama N, Figueroa CA. Effects of non-Newtonian viscosity on arterial and venous flow and transport. Sci Rep 2022; 12:20568. [PMID: 36446813 PMCID: PMC9709089 DOI: 10.1038/s41598-022-19867-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2022] [Accepted: 09/06/2022] [Indexed: 11/30/2022] Open
Abstract
It is well known that blood exhibits non-Newtonian viscosity, but it is generally modeled as a Newtonian fluid. However, in situations of low shear rate, the validity of the Newtonian assumption is questionable. In this study, we investigated differences between Newtonian and non-Newtonian hemodynamic metrics such as velocity, vorticity, and wall shear stress. In addition, we investigated cardiovascular transport using two different approaches, Eulerian mass transport and Lagrangian particle tracking. Non-Newtonian solutions revealed important differences in both hemodynamic and transport metrics relative to the Newtonian model. Most notably for the hemodynamic metrics, in-plane velocity and vorticity were consistently larger in the Newtonian approximation for both arterial and venous flows. Conversely, wall shear stresses were larger for the non-Newtonian case for both the arterial and venous models. Our results also indicate that for the Lagrangian metrics, the history of accumulated shear was consistently larger for both arterial and venous flows in the Newtonian approximation. Lastly, our results also suggest that the Newtonian model produces larger near wall and luminal mass transport values compared to the non-Newtonian model, likely due to the increased vorticity and recirculation. These findings demonstrate the importance of accounting for non-Newtonian behavior in cardiovascular flows exhibiting significant regions of low shear rate and recirculation.
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Affiliation(s)
- Sabrina Lynch
- grid.214458.e0000000086837370Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI USA
| | - Nitesh Nama
- grid.24434.350000 0004 1937 0060Department of Mechanical & Materials Engineering, University of Nebraska, Lincoln, NE USA
| | - C. Alberto Figueroa
- grid.214458.e0000000086837370Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI USA ,grid.214458.e0000000086837370Department of Surgery, University of Michigan, Ann Arbor, MI USA
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23
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Koivumäki JT, Hoffman J, Maleckar MM, Einevoll GT, Sundnes J. Computational cardiac physiology for new modelers: Origins, foundations, and future. Acta Physiol (Oxf) 2022; 236:e13865. [PMID: 35959512 DOI: 10.1111/apha.13865] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 08/04/2022] [Accepted: 08/05/2022] [Indexed: 01/29/2023]
Abstract
Mathematical models of the cardiovascular system have come a long way since they were first introduced in the early 19th century. Driven by a rapid development of experimental techniques, numerical methods, and computer hardware, detailed models that describe physical scales from the molecular level up to organs and organ systems have been derived and used for physiological research. Mathematical and computational models can be seen as condensed and quantitative formulations of extensive physiological knowledge and are used for formulating and testing hypotheses, interpreting and directing experimental research, and have contributed substantially to our understanding of cardiovascular physiology. However, in spite of the strengths of mathematics to precisely describe complex relationships and the obvious need for the mathematical and computational models to be informed by experimental data, there still exist considerable barriers between experimental and computational physiological research. In this review, we present a historical overview of the development of mathematical and computational models in cardiovascular physiology, including the current state of the art. We further argue why a tighter integration is needed between experimental and computational scientists in physiology, and point out important obstacles and challenges that must be overcome in order to fully realize the synergy of experimental and computational physiological research.
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Affiliation(s)
- Jussi T Koivumäki
- Faculty of Medicine and Health Technology, and Centre of Excellence in Body-on-Chip Research, Tampere University, Tampere, Finland
| | - Johan Hoffman
- Division of Computational Science and Technology, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Mary M Maleckar
- Computational Physiology Department, Simula Research Laboratory, Oslo, Norway
| | - Gaute T Einevoll
- Centre for Integrative Neuroplasticity, University of Oslo, Oslo, Norway.,Department of Physics, University of Oslo, Oslo, Norway.,Department of Physics, Norwegian University of Life Sciences, Ås, Norway
| | - Joakim Sundnes
- Computational Physiology Department, Simula Research Laboratory, Oslo, Norway
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24
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On non-Kolmogorov turbulence in blood flow and its possible role in mechanobiological stimulation. Sci Rep 2022; 12:13166. [PMID: 35915207 PMCID: PMC9343407 DOI: 10.1038/s41598-022-16079-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Accepted: 07/04/2022] [Indexed: 01/09/2023] Open
Abstract
The study of turbulence in physiologic blood flow is important due to its strong relevance to endothelial mechanobiology and vascular disease. Recently, Saqr et al. (Sci Rep 10, 15,492, 2020) discovered non-Kolmogorov turbulence in physiologic blood flow in vivo, traced its origins to the Navier–Stokes equation and demonstrated some of its properties using chaos and hydrodynamic-stability theories. The present work extends these findings and investigates some inherent characteristics of non-Kolmogorov turbulence in monoharmonic and multiharmonic pulsatile flow under ideal physiologic conditions. The purpose of this work is to propose a conjecture for the origins for picoNewton forces that are known to regulate endothelial cells’ functions. The new conjecture relates these forces to physiologic momentum-viscous interactions in the near-wall region of the flow. Here, we used high-resolution large eddy simulation (HRLES) to study pulsatile incompressible flow in a straight pipe of \documentclass[12pt]{minimal}
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\begin{document}$$L/D=20$$\end{document}L/D=20. The simulations presented Newtonian and Carreau–Yasuda fluid flows, at \documentclass[12pt]{minimal}
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\begin{document}$$R{e}_{m}\approx 250$$\end{document}Rem≈250, each represented by one, two and three boundary harmonics. Comparison was established based on maintaining constant time-averaged mass flow rate in all simulations. First, we report the effect of primary harmonics on the global power budget using primitive variables in phase space. Second, we describe the non-Kolmogorov turbulence in frequency domain. Third, we investigate the near-wall coherent structures in time and space domains. Finally, we propose a new conjecture for the role of turbulence in endothelial cells’ mechanobiology. The proposed conjecture correlates near-wall turbulence to a force field of picoNewton scale, suggesting possible relevance to endothelial cells mechanobiology.
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25
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The Detrimental Role of Intraluminal Thrombus Outweighs Protective Advantage in Abdominal Aortic Aneurysm Pathogenesis: The Implications for the Anti-Platelet Therapy. Biomolecules 2022; 12:biom12070942. [PMID: 35883500 PMCID: PMC9313225 DOI: 10.3390/biom12070942] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Revised: 06/20/2022] [Accepted: 07/01/2022] [Indexed: 02/01/2023] Open
Abstract
Abdominal aortic aneurysm (AAA) is a common cardiovascular disease resulting in morbidity and mortality in older adults due to rupture. Currently, AAA treatment relies entirely on invasive surgical treatments, including open repair and endovascular, which carry risks for small aneurysms (diameter < 55 mm). There is an increasing need for the development of pharmacological intervention for early AAA. Over the last decade, it has been increasingly recognized that intraluminal thrombus (ILT) is involved in the growth, remodeling, and rupture of AAA. ILT has been described as having both biomechanically protective and biochemically destructive properties. Platelets are the second most abundant cells in blood circulation and play an integral role in the formation, expansion, and proteolytic activity of ILT. However, the role of platelets in the ILT-potentiated AAA progression/rupture remains unclear. Researchers are seeking pharmaceutical treatment strategies (e.g., anti-thrombotic/anti-platelet therapies) to prevent ILT formation or expansion in early AAA. In this review, we mainly focus on the following: (a) the formation/deposition of ILT in the progression of AAA; (b) the dual role of ILT in the progression of AAA (protective or detrimental); (c) the function of platelet activity in ILT formation; (d) the application of anti-platelet drugs in AAA. Herein, we present challenges and future work, which may motivate researchers to better explain the potential role of ILT in the pathogenesis of AAA and develop anti-platelet drugs for early AAA.
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26
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Chuchalerm N, Sawangtong W, Wiwatanapataphee B, Siriapisith T. Study of Non-Newtonian blood flow - heat transfer characteristics in the human coronary system with an external magnetic field. MATHEMATICAL BIOSCIENCES AND ENGINEERING : MBE 2022; 19:9550-9570. [PMID: 35942772 DOI: 10.3934/mbe.2022444] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
This paper proposes a novel mathematical model of non-Newtonian blood flow and heat transfer in the human coronary system with an external magnetic field. As the blood viscosity is assumed to depend not only on shear rate but also on temperature and magnet strength, the modified Carreau-Yasuda viscosity model is formulated. The computational domain includes the base of the aorta, the right coronary artery, and the left coronary artery, with the left circumflex and left anterior descending arteries. The element-based finite volume method is derived for the solution of the proposed model. Numerical simulations are carried out to investigate the magnetic field effect on the blood flow-heat transfer characteristic in the human coronary system. It is found that the magnetic field has a significant impact on fluid viscosity, leading to enhanced fluid velocity.
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Affiliation(s)
- Nattawan Chuchalerm
- Department of Mathematics, Faculty of Science, Mahidol University, Bangkok 10400, Thailand
- Centre of Excellence in Mathematics, Commission on Higher Education, Bangkok 10400, Thailand
| | - Wannika Sawangtong
- Department of Mathematics, Faculty of Science, Mahidol University, Bangkok 10400, Thailand
- Centre of Excellence in Mathematics, Commission on Higher Education, Bangkok 10400, Thailand
| | - Benchawan Wiwatanapataphee
- School of Electrical Engineering, Computing and Mathematical Sciences, Curtin University, Perth, WA 6845, Australia
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27
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Morris L, Tierney P, Hynes N, Sultan S. An in vitro Assessment of the Haemodynamic Features Occurring Within the True and False Lumens Separated by a Dissection Flap for a Patient-Specific Type B Aortic Dissection. Front Cardiovasc Med 2022; 9:797829. [PMID: 35369331 PMCID: PMC8968342 DOI: 10.3389/fcvm.2022.797829] [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: 10/19/2021] [Accepted: 02/15/2022] [Indexed: 11/14/2022] Open
Abstract
One of the highest mortality rates of cardiovascular diseases is aortic dissections with challenging treatment options. Currently, less study has been conducted in developing in vitro patient-specific Type B aortic dissection models, which mimic physiological flow conditions along the true and false lumens separated by a dissection flap with multiple entry and exit tears. A patient-specific Stanford Type B aortic dissection scan was replicated by an in-house manufactured automatic injection moulding system and a novel modelling technique for creating the ascending aorta, aortic arch, and descending aorta incorporating arterial branching, the true/false lumens, and dissection flap with entry and exit intimal tears. The physiological flowrates and pressure values were monitored, which identified jet stream fluid flows entering and exiting the dissection tears. Pressure in the aorta’s true lumen region was controlled at 125/85 mmHg for systolic and diastolic values. Pressure values were obtained in eight sections along the false lumen using a pressure transducer. The true lumen systolic pressure varied from 122 to 128 mmHg along the length. Flow patterns were monitored by ultrasound along 12 sections. Detailed images obtained from the ultrasound transducer probe showed varied flow patterns with one or multiple jet steam vortices along the aorta model. The dissection flap movement was assessed at four sections of the patient-specific aorta model. The displacement values of the flap varied from 0.5 to 3 mm along the model. This model provides a unique insight into aortic dissection flow patterns and pressure distributions. This dissection phantom model can be used to assess various treatment options based on the surgical, endovascular, or hybrid techniques.
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Affiliation(s)
- Liam Morris
- Galway-Mayo Institute of Technology, Galway, Ireland
- Galway Medical Technology Centre, Department of Mechanical and Industrial Engineering, Galway-Mayo Institute of Technology, Galway, Ireland
- Medical and Engineering Technology Centre, Department of Mechanical and Industrial Engineering, Galway-Mayo Institute of Technology, Galway, Ireland
- Lero – Science Foundation Ireland Research Centre for Software, Galway-Mayo Institute of Technology, Galway, Ireland
- *Correspondence: Liam Morris,
| | - Paul Tierney
- Galway Medical Technology Centre, Department of Mechanical and Industrial Engineering, Galway-Mayo Institute of Technology, Galway, Ireland
- Medical and Engineering Technology Centre, Department of Mechanical and Industrial Engineering, Galway-Mayo Institute of Technology, Galway, Ireland
| | - Niamh Hynes
- CÚRAM, National University of Ireland, Galway, Ireland
| | - Sherif Sultan
- Western Vascular Institute, Department of Vascular and Endovascular Surgery, University College Hospital Galway, Galway, Ireland
- Department of Vascular and Endovascular Surgery, Galway Clinic, Royal College of Surgeons in Ireland, Doughiska, Ireland
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28
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Almeida GDC, Gomes BADA, Azevedo FSD, Kalaun K, Ibanez I, Teixeira PS, Gottlieb I, Melo MM, Oliveira GMMD, Nieckele AO. Fluidodinâmica Computacional na Avaliação do Risco Futuro de Aneurismas de Aorta Ascendente. Arq Bras Cardiol 2022; 118:448-460. [PMID: 35262580 PMCID: PMC8856676 DOI: 10.36660/abc.20200926] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Accepted: 02/24/2021] [Indexed: 11/18/2022] Open
Abstract
Fundamentos Uma metodologia para identificação de pacientes portadores de aneurisma de aorta ascendente (AAAs) sob alto risco de remodelamento aórtico não está completamente definida. Objetivo Esta pesquisa objetiva caracterizar numericamente o fluxo sanguíneo aórtico, relacionando a distribuição do estresse mecânico resultante com o crescimento de AAAs. Métodos Estudo analítico, observacional, unicêntrico, em que um protocolo de fluidodinâmica computacional (CFD - Computacional Fluid Dynamics) foi aplicado a imagens de angiotomografia computadorizada (ATC) de aorta de pacientes portadores de AAAs. Duas ATC de aorta com pelo menos um ano de intervalo foram obtidas. Dados clínicos dos pacientes foram registrados e, a partir das imagens de ATC, foram gerados modelos tridimensionais. Foram realizados estudos do campo de velocidade e estruturas coerentes (vórtices) com o objetivo de relacioná-los ao crescimento ou não do aneurisma e, posteriormente, compará-los com os dados clínicos dos pacientes. O teste de Kolmogorov-Smirnov foi utilizado para avaliar a normalidade da amostra e o teste não-paramétrico Wilcoxon signed-rank foi aplicado para comparações de dados pareados entre os ângulos aórticos. A significância estatística foi fixada em 5%. Resultados Para o grupo que apresentou crescimento do aneurisma, a incidência do jato na parede aórtica gerou áreas de recirculação posterior ao jato, induzindo à formação de vórtices complexos, ocasionando um incremento na pressão média no endotélio aórtico. O grupo sem crescimento do aneurisma apresentou diminuição na pressão média. Conclusão Este estudo piloto mostrou que a CFD baseada em ATC pode, em um futuro próximo, ser uma ferramenta auxiliar na identificação dos padrões de fluxo associados ao processo de remodelamento de AAAs.
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29
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Zambrano BA, Gharahi H, Lim CY, Lee W, Baek S. Association of vortical structures and hemodynamic parameters for regional thrombus accumulation in abdominal aortic aneurysms. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2022; 38:e3555. [PMID: 34859615 PMCID: PMC8858872 DOI: 10.1002/cnm.3555] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Revised: 11/18/2021] [Accepted: 11/27/2021] [Indexed: 05/08/2023]
Abstract
The intraluminal thrombus (ILT) has been shown to negatively impact the progression of the abdominal aortic aneurysms (AAAs). The formation of this thrombus layer has been connected to the local flow environment within AAAs, but the specific mechanisms leading to thrombus formation are still not fully understood. Our study investigated the association between vortical structures, near-wall hemodynamic metrics (e.g., time averaged wall shear stress (TAWSS) and oscillatory shear index (OSI)), and ILT accumulation in a longitudinal cohort of 14 AAAs (53 scans total). Vortices and hemodynamic parameters were estimated using hemodynamic simulations performed to each scan of each patient and compared to local 3D changes of ILT thickness between two consecutive scans (ΔILT). Results showed that vortices formed and remained strong and close to the lumen surface in AAAs without an ILT, while in AAAs with ILTs these detached from the lumen surface and dissipated nearby wall region where an increase in ILT thickness was observed. Although low TAWSS was observed in regions with and without ILT accumulation, an inverse correlation between ∆ ILT and TAWSS was observed within the regions that experienced a thrombus growth. Our results support the idea that vortical structures might be playing a role modulating ILT accumulation into specific wall regions. Also, it submits the idea that the low TAWSS will be modulating the growth of thrombus within these preferred ILT accumulated regions.
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Affiliation(s)
- Byron A Zambrano
- J. Mike Walker '66 Department of Mechanical Engineering, Texas A&M University, College Station, Texas, USA
| | - Hamidreza Gharahi
- Department of Mechanical Engineering, Michigan State University, East Lansing, Michigan, USA
| | - Chae Young Lim
- Department of Statistics, Seoul National University, Seoul, Korea
| | - Whal Lee
- Department of Radiology, Seoul National University, Seoul, Korea
| | - Seungik Baek
- Department of Mechanical Engineering, Michigan State University, East Lansing, Michigan, USA
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30
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Fatma K, Carine GC, Marine G, Philippe P, Valérie D. Numerical modeling of residual type B aortic dissection: longitudinal analysis of favorable and unfavorable evolution. Med Biol Eng Comput 2022; 60:769-783. [PMID: 35076858 DOI: 10.1007/s11517-021-02480-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 11/24/2021] [Indexed: 11/26/2022]
Abstract
Residual type B aortic dissection was numerically investigated to highlight the contribution of biomechanical parameters to the pathology's evolution. Patient-specific geometries from cases involving both favorable and unfavorable evolution were modeled to assess their hemodynamic features. This original approach was supported by a longitudinal study confirming the association between morphological changes, hemodynamic features, adverse clinical outcomes, and CT-angioscan observations on the same patient. Comparing one patient with unfavorable evolution with one with favorable one, we identify potential biomechanical indicators predictive of unfavorable evolution: (i) a patent false lumen with a flow rate above 50% of inlet flow rate; (ii) high wall shear stress above 18 Pa at entry tears, and above 10 Pa at some regions of the false lumen wall; (iii) low time-averaged wall shear stress in distal false lumen below 0.5 Pa; (iv) vortical structure dynamics. Although these comparisons could only be conducted on 2 patients and need to be confirmed by a larger number of cases, our findings point to these hemodynamic markers as possible candidates for early evaluation of the pathology's evolution towards an unfavorable scenario. Graphical Abstract Correlation between hemodynamics index and thrombus initiation for unfavorable case. ET2 and ET3 are entry tear numbers 2 and 3 respectively. WSS is wall shear stress. TAWSS is time average shear stress.
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Affiliation(s)
- Khannous Fatma
- Aix Marseille Univ, CNRS, IRPHE-UMR7342, Ecole Centrale, Marseille, France
| | | | - Gaudry Marine
- Aix Marseille Univ, CNRS, IRPHE-UMR7342, Ecole Centrale, Marseille, France
- Aix Marseille Univ, APHM, Timone Hospital, Department of Vascular Surgery, Marseille, France
| | - Piquet Philippe
- Aix Marseille Univ, APHM, Timone Hospital, Department of Vascular Surgery, Marseille, France
| | - Deplano Valérie
- Aix Marseille Univ, CNRS, IRPHE-UMR7342, Ecole Centrale, Marseille, France.
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31
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Sun W, Zheng J, Gao Y. Targeting Platelet Activation in Abdominal Aortic Aneurysm: Current Knowledge and Perspectives. Biomolecules 2022; 12:biom12020206. [PMID: 35204706 PMCID: PMC8961578 DOI: 10.3390/biom12020206] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2021] [Revised: 01/21/2022] [Accepted: 01/22/2022] [Indexed: 01/28/2023] Open
Abstract
Abdominal aortic aneurysm (AAA) is a potentially fatal vascular disease that involves complex multifactorial hemodynamic, thrombotic, inflammatory, and aortic wall remodeling processes. However, its mechanisms are incompletely understood. It has become increasingly clear that platelets are involved in pathological processes of vascular diseases beyond their role in hemostasis and thrombosis. Platelet activation with membrane receptors and secreted mediators promotes thrombus formation and the accumulation of inflammatory cells, which may play an important role in the development of AAA by destroying the structural integrity and stability of the vessel wall. Turbulent blood flow in aortic aneurysms promotes platelet activation and aggregation. Platelet count and heterogeneity are important predictive, diagnostic, and prognostic indicators of AAA. We summarize the relationship between platelet activation and AAA development and propose future research directions and possible clinical applications.
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Affiliation(s)
- Weiliang Sun
- Institute of Clinical Medicine Sciences, China-Japan Friendship Hospital, 2 Yinghua Dongjie, Chaoyang District, Beijing 100029, China;
| | - Jingang Zheng
- Department of Cardiology, China-Japan Friendship Hospital, 2 Yinghua Dongjie, Chaoyang District, Beijing 100029, China;
| | - Yanxiang Gao
- Department of Cardiology, China-Japan Friendship Hospital, 2 Yinghua Dongjie, Chaoyang District, Beijing 100029, China;
- Correspondence:
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32
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Darwish A, Norouzi S, Kadem L. Spectral-Clustering of Lagrangian Trajectory Graphs: Application to Abdominal Aortic Aneurysms. Cardiovasc Eng Technol 2021; 13:504-513. [PMID: 34845627 DOI: 10.1007/s13239-021-00590-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Accepted: 11/01/2021] [Indexed: 11/29/2022]
Abstract
PURPOSE Identification of coherent structures in cardiovascular flows is crucial to describe the transport and mixing of blood. Coherent structures can highlight locations where minimal blood mixing takes place, thus, potential thrombus formation can be expected thither. Graph-based approaches have recently been introduced in order to describe fluid transport and mixing between multiple Lagrangian trajectories, where each trajectory serves as a node that can be connected to another trajectory based on their relative distance during the course of time. METHODS In this study, we compute the Lagrangian trajectories from in vitro planar instantaneous velocity fields in two models of abdominal aortic aneurysms, (AAA) namely single bulge and bi-lobed. Then, we construct unweighted and undirected graphs based on the pairwise distance of Lagrangian trajectories. We report local measures of the graph namely the degree and the clustering coefficient. We also perform spectral clustering of the graph Laplacian to extract the flow coherent sets. RESULTS Local graph measures reveal fluid regions of high mixing such as vortex boundaries. Through spectral clustering, the fluid is partitioned into a reduced number of coherent sets where within each set, inner mixing of fluid is maximized while the fluid mixing between different coherent sets is minimized. The approach reveals multiple coherent sets adjacent to the AAA bulge that have sustained this adjacency to the wall through their coherent motion during one cardiac cycle. CONCLUSION Identifying coherent sets enables tracking their transport during the cardiac cycle and identify their role in the flow dynamics. Moreover, the size and the transport of the long residing coherent sets inside the AAA bulges can be deduced which may aid in predicting thrombus formation at such location.
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Affiliation(s)
- Ahmed Darwish
- Laboratory of Cardiovascular Fluid Dynamics, Concordia University, Montréal, QC, H3G 1M8, Canada. .,Mechanical Engineering Department, Assiut University, 71515, Assiut, Egypt.
| | - Shahrzad Norouzi
- Laboratory of Cardiovascular Fluid Dynamics, Concordia University, Montréal, QC, H3G 1M8, Canada
| | - Lyes Kadem
- Laboratory of Cardiovascular Fluid Dynamics, Concordia University, Montréal, QC, H3G 1M8, Canada
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Pandey PK, Das MK. Effect of foam insertion in aneurysm sac on flow structures in parent lumen: relating vortex structures with disturbed shear. Phys Eng Sci Med 2021; 44:1231-1248. [PMID: 34581959 DOI: 10.1007/s13246-021-01058-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Accepted: 09/05/2021] [Indexed: 11/26/2022]
Abstract
Numerous studies suggest that disturbed shear, causing endothelium dysfunction, can be related to neighboring vortex structures. With this motivation, this study presents a methodology to characterize the vortex structures. Precisely, we use mapping and characterization of vortex structures' changes to relate it with the hemodynamic indicators of disturbed shear. Topological features of vortex core lines (VCLs) are used to quantify the changes in vortex structures. We use the Sujudi-Haimes algorithm to extract the VCLs from the flow simulation results. The idea of relating vortex structures with disturbed shear is demonstrated for cerebral arteries with aneurysms virtually treated by inserting foam in the sac. To get physiologically realistic flow fields, we simulate blood flow in two patient-specific geometries before and after foam insertion, with realistic velocity waveform imposed at the inlet, using the Carreau-Yasuda model to mimic the shear-thinning behavior. With homogenous porous medium assumption, flow through the foam is modeled using the Forchheimer-Brinkman extended Darcy model. Results show that foam insertion increases the number of VCLs in the parent lumen. The average length of VCL increases by 168.9% and 55.6% in both geometries. For both geometries under consideration, results demonstrate that the region with increased disturbed shear lies in the same arterial segment exhibiting an increase in the number of oblique VCLs. Based on the findings, we conjecture that an increase in oblique VCLs is related to increased disturbed shear at the neighboring portion of the arterial wall.
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Affiliation(s)
- Pawan Kumar Pandey
- Department of Mechanical Engineering, Indian Institute of Technology Kanpur, Kanpur, 208016, Uttar Pradesh, India
| | - Malay Kumar Das
- Department of Mechanical Engineering, Indian Institute of Technology Kanpur, Kanpur, 208016, Uttar Pradesh, India.
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Boyd AJ. Intraluminal thrombus: Innocent bystander or factor in abdominal aortic aneurysm pathogenesis? JVS Vasc Sci 2021; 2:159-169. [PMID: 34617066 PMCID: PMC8489244 DOI: 10.1016/j.jvssci.2021.02.001] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Accepted: 02/20/2021] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND Abdominal aortic aneurysms (AAAs) represent a complex multifactorial hemodynamic, thrombotic, and inflammatory process that can ultimately result in aortic rupture and death. Despite improved screening and surgical management of AAAs, the mortality rates have remained high after rupture, and little progress has occurred in the development of nonoperative treatments. Intraluminal thrombus (ILT) is present in most AAAs and might be involved in AAA pathogenesis. The present review examined the latest clinical and experimental evidence for possible involvement of the ILT in AAA growth and rupture. METHODS A literature review was performed after a search of the PubMed database from 2012 to June 2020 using the terms "abdominal aortic aneurysm" and "intraluminal thrombus." RESULTS The structure, composition, and hemodynamics of ILT formation and propagation were reviewed in relation to the hemostatic and proteolytic factors favoring ILT deposition. The potential effects of the ILT on AAA wall degeneration and rupture, including a review of the current controversies regarding the position, thickness, and composition of ILT, are presented. Although initially potentially protective against increased wall stress, increasing evidence has shown that an increased volume and greater age of the ILT have direct detrimental effects on aortic wall integrity, which might predispose to an increased rupture risk. CONCLUSIONS ILT does not appear to be an innocent bystander in AAA pathophysiology. However, its exact role remains elusive and controversial. Despite computational evidence of a possible protective role of the ILT in reducing wall stress, increasing evidence has shown that the ILT promotes AAA wall degeneration in humans and in animal models. Further research, with large animal models and with more chronic ILT is crucial for a better understanding of the role of the ILT in AAAs and for the potential development of targeted therapies to slow or halt AAA progression.
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Affiliation(s)
- April J. Boyd
- Department of Vascular Surgery, University of Manitoba, Winnipeg, Manitoba, Canada
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Le-Nguyen A, Joharifard S, Côté G, Borsuk D, Ghali R, Lallier M. Neonatal Microsurgical Repair of a Congenital Abdominal Aortic Aneurysm with a Cadaveric Graft. European J Pediatr Surg Rep 2021; 9:e23-e27. [PMID: 33680709 PMCID: PMC7929720 DOI: 10.1055/s-0041-1723019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 08/18/2020] [Indexed: 10/28/2022] Open
Abstract
Congenital abdominal aortic aneurysms (AAA) are an extremely rare entity. We present the case of a female fetus diagnosed with an AAA on routine prenatal ultrasound. A postnatal computed tomography angiogram revealed an infrarenal AAA with a narrow proximal neck. Surgery was performed on day of life 14 using a cadaveric femoral artery graft. The proximal anastomosis was performed under the microscope given the severity of the aortic stenosis and the proximity of the renal arteries. The patient's postoperative course was uneventful and she is developing normally 1 year after surgery. The graft remains permeable, albeit with evidence of proximal and distal stenosis and graft calcification on imaging.
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Affiliation(s)
- Annie Le-Nguyen
- Department of Surgery, Division of General Surgery, Saint Justine Hospital, Montreal, Quebec, Canada
| | - Shahrzad Joharifard
- Department of Surgery, Division of Pediatric Surgery, Saint Justine Hospital, Montreal, Quebec, Canada
| | - Geneviève Côté
- Department of Anesthesiology, Saint Justine Hospital, Montreal, Quebec, Canada
| | - Daniel Borsuk
- Department of Surgery, Division of Plastic Surgery, Saint Justine Hospital, Montreal, Quebec, Canada
| | - Rafik Ghali
- Department of Surgery, Division of Vascular Surgery, Hôpital Maisonneuve-Rosemont, Montreal, Quebec, Canada
| | - Michel Lallier
- Department of Surgery, Division of Pediatric Surgery, Saint Justine Hospital, Montreal, Quebec, Canada
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Gutierrez MA. Computational Analysis of Fluid Dynamics in the Transcatheter Aortic Valve Replacement. Arq Bras Cardiol 2020; 115:688-689. [PMID: 33111870 PMCID: PMC8386972 DOI: 10.36660/abc.20201002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Affiliation(s)
- Marco A Gutierrez
- Instituto do Coração (InCor), Faculdade de Medicina da Universidade de São Paulo (FMUSP), São Paulo, SP - Brasil
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Zhang X, Luo M, Fang K, Li J, Peng Y, Zheng L, Shu C. Analysis of the formation mechanism and occurrence possibility of Post-Stenotic Dilatation of the aorta by CFD approach. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2020; 194:105522. [PMID: 32422474 DOI: 10.1016/j.cmpb.2020.105522] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 04/24/2020] [Accepted: 04/25/2020] [Indexed: 06/11/2023]
Abstract
BACKGROUND AND OBJECTIVE Post-Stenotic Dilatation (PSD), the common complication of coarctation of the aorta (COA), is a progressive disease involving aortic aneurysm and even rupture. However, there has been no definitive method that could investigate the mechanism of PSD formation, progression and rupture. The purpose of the present work is to analyze the mechanism behind PSD formation and to further assess the risk of COA patients with different coarctation degrees deteriorating into PSD. METHOD Three-dimensional non-Newtonian (Carreau-Yasuda) hemodynamic simulations are performed throughout the cardiac cycle, and a novel parameter (λci¯ intensity) is proposed to evaluate the intensity of vortices within the aorta. The PSD geometry is reconstructed from Computed Tomography scans. To analyze the formation mechanism and occurrence possibility of PSD, the computer technology is utilized to restore the expansive and/or narrow regions to obtain its previous state (COA) and control group (Normal), and to modify the minimum diameter to obtain the aortas with different coarctation degrees. The clinical cases of pre- and post-operation are further introduced to verify the analysis. RESULTS Compared with the Normal, the vortical structures with higher swirling strength are generated and accumulated at the downstream of the coarctation segment after COA occurrence, and partially disappear in the wake of PSD formation. The sequence of λci¯ intensity is COA > PSD > Normal and pre-operation > post-operation. With increasing the degree of coarctation, the λci¯ intensity is higher and the jet-flow becomes more drastic. CONCLUSIONS The formation of PSD is caused by the vortical structures with higher swirling strength accumulating at the downstream of the coarctation segment. An increase in coarctation degree elevates the risk of PSD occurrence and even aneurysmal dilatation.
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Affiliation(s)
- Xuelan Zhang
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing 10083, China; School of Mathematics and Physics, University of Science and Technology Beijing, Beijing 100083, China
| | - Mingyao Luo
- Department of Vascular Surgery, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100037, China
| | - Kun Fang
- Department of Vascular Surgery, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100037, China
| | - Jiehua Li
- Department of Vascular Surgery, the Second Xiangya Hospital, Central South University, Changsha, 410000, China
| | - Yuan Peng
- Department of Vascular Surgery, the Second Xiangya Hospital, Central South University, Changsha, 410000, China
| | - Liancun Zheng
- School of Mathematics and Physics, University of Science and Technology Beijing, Beijing 100083, China.
| | - Chang Shu
- Department of Vascular Surgery, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100037, China.
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Kyriakou F, Maclean C, Dempster W, Nash D. Efficiently Simulating an Endograft Deployment: A Methodology for Detailed CFD Analyses. Ann Biomed Eng 2020; 48:2449-2465. [PMID: 32394221 PMCID: PMC7505889 DOI: 10.1007/s10439-020-02519-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Accepted: 04/24/2020] [Indexed: 01/10/2023]
Abstract
Numerical models of endografts for the simulation of endovascular aneurysm repair are increasingly important in the improvement of device designs and patient outcomes. Nevertheless, current finite element analysis (FEA) models of complete endograft devices come at a high computational cost, requiring days of runtime, therefore restricting their applicability. In the current study, an efficient FEA model of the Anaconda™ endograft (Terumo Aortic, UK) was developed, able to yield results in just over 4 h, an order of magnitude less than similar models found in the literature. The model was used to replicate a physical device that was deployed in a 3D printed aorta and comparison of the two shapes illustrated a less than 5 mm placement error of the model in the regions of interest, consistent with other more computationally intensive models in the literature. Furthermore, the final goal of the study was to utilize the deployed fabric model in a hemodynamic analysis that would incorporate realistic fabric folds, a feature that is almost always omitted in similar simulations. By successfully exporting the deployed graft geometry into a flow analysis, it was illustrated that the inclusion of fabric wrinkles enabled clinically significant flow patterns such as flow stagnation and recirculation to be detected, paving the way for this modelling methodology to be used in future for stent design optimisation.
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Affiliation(s)
- Faidon Kyriakou
- Department of Mechanical and Aerospace Engineering, University of Strathclyde, 75 Montrose Street, Glasgow, G1 1XJ, UK.
| | | | - William Dempster
- Department of Mechanical and Aerospace Engineering, University of Strathclyde, 75 Montrose Street, Glasgow, G1 1XJ, UK
| | - David Nash
- Department of Mechanical and Aerospace Engineering, University of Strathclyde, 75 Montrose Street, Glasgow, G1 1XJ, UK
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Lipp SN, Niedert EE, Cebull HL, Diorio TC, Ma JL, Rothenberger SM, Stevens Boster KA, Goergen CJ. Computational Hemodynamic Modeling of Arterial Aneurysms: A Mini-Review. Front Physiol 2020; 11:454. [PMID: 32477163 PMCID: PMC7235429 DOI: 10.3389/fphys.2020.00454] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Accepted: 04/09/2020] [Indexed: 01/02/2023] Open
Abstract
Arterial aneurysms are pathological dilations of blood vessels, which can be of clinical concern due to thrombosis, dissection, or rupture. Aneurysms can form throughout the arterial system, including intracranial, thoracic, abdominal, visceral, peripheral, or coronary arteries. Currently, aneurysm diameter and expansion rates are the most commonly used metrics to assess rupture risk. Surgical or endovascular interventions are clinical treatment options, but are invasive and associated with risk for the patient. For aneurysms in locations where thrombosis is the primary concern, diameter is also used to determine the level of therapeutic anticoagulation, a treatment that increases the possibility of internal bleeding. Since simple diameter is often insufficient to reliably determine rupture and thrombosis risk, computational hemodynamic simulations are being developed to help assess when an intervention is warranted. Created from subject-specific data, computational models have the potential to be used to predict growth, dissection, rupture, and thrombus-formation risk based on hemodynamic parameters, including wall shear stress, oscillatory shear index, residence time, and anomalous blood flow patterns. Generally, endothelial damage and flow stagnation within aneurysms can lead to coagulation, inflammation, and the release of proteases, which alter extracellular matrix composition, increasing risk of rupture. In this review, we highlight recent work that investigates aneurysm geometry, model parameter assumptions, and other specific considerations that influence computational aneurysm simulations. By highlighting modeling validation and verification approaches, we hope to inspire future computational efforts aimed at improving our understanding of aneurysm pathology and treatment risk stratification.
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Affiliation(s)
- Sarah N. Lipp
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, United States
| | - Elizabeth E. Niedert
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, United States
| | - Hannah L. Cebull
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, United States
| | - Tyler C. Diorio
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, United States
| | - Jessica L. Ma
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, United States
| | - Sean M. Rothenberger
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, United States
| | - Kimberly A. Stevens Boster
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, United States
- School of Mechanical Engineering, Purdue University, West Lafayette, IN, United States
| | - Craig J. Goergen
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, United States
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Lee SH, Kang PK. Three-Dimensional Vortex-Induced Reaction Hot Spots at Flow Intersections. PHYSICAL REVIEW LETTERS 2020; 124:144501. [PMID: 32338949 DOI: 10.1103/physrevlett.124.144501] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Accepted: 03/06/2020] [Indexed: 06/11/2023]
Abstract
We show the emergence of reaction hot spots induced by three-dimensional (3D) vortices with a simple A+B→C reaction. We conduct microfluidics experiments to visualize the spatial map of the reaction rate with a chemiluminescence reaction and cross validate the results with direct numerical simulations. 3D vortices form at spiral-saddle-type stagnation points, and the 3D vortex flow topology is essential for initiating reaction hot spots. The effect of vortices on mixing and reaction becomes more vigorous for rough-walled channels, and our findings are valid over wide ranges of channel dimensions and Damköhler numbers.
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Affiliation(s)
- Sang H Lee
- Department of Earth and Environmental Sciences, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - Peter K Kang
- Department of Earth and Environmental Sciences, University of Minnesota, Minneapolis, Minnesota 55455, USA
- Saint Anthony Falls Laboratory, University of Minnesota, Minneapolis, Minnesota 55455, USA
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Goode D, Dhaliwal R, Mohammadi H. Transcatheter Mitral Valve Replacement: State of the Art. Cardiovasc Eng Technol 2020; 11:229-253. [DOI: 10.1007/s13239-020-00460-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Accepted: 02/14/2020] [Indexed: 10/24/2022]
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Wang Z, Wang C, Li F, Zhao Y. Endovascular repair during complex thoracic aortic dissection using a micropore stent graft: Midterm follow-up clinical outcomes. Catheter Cardiovasc Interv 2020; 95:E111-E119. [PMID: 31408266 PMCID: PMC7078903 DOI: 10.1002/ccd.28437] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Revised: 07/09/2019] [Accepted: 07/27/2019] [Indexed: 12/22/2022]
Abstract
Objective This study explored the clinical efficacy and hemodynamic effects of the micropore stent graft (MSG) that could promote aortic remodeling and preserve important organ branches. Methods We conducted a retrospective analysis of 26 patients who underwent endovascular repair using an MSG for DeBakey types I and III TAD at our center between December 2014 and December 2017. The main efficacy parameters were rupture of the false lumen or dissection‐related death, conversion to open repair, secondary reintervention, branch vessel patency, and the hemodynamic effects of TAD at 12 months. Results Dissection rupture, dissection‐related mortality, conversion to open repair, and secondary reintervention rates at 12 months were 0, 3.9, 0, and 0%, respectively. In the 24 patients with more than 6 months of follow‐up, micropore stents were implanted to cover 39 openings in aortic arch branches, 91.7% (22/24) presented with complete thrombosis in the false lumen, 8.3% (2/24) presented with partial thrombosis in the false lumen, 35.2% (6/17) presented with a thrombus in the false lumen that was completely absorbed, and all 39 branches were patent. After surgery, pressure peak value and fluctuation along with the degree and range of unstable blood flow in the aortic lumen decreased. Conclusions For type I and type III thoracic artic dissection, endovascular treatment with an MSG may be a safe and effective treatment option with a good midterm outcome.
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Affiliation(s)
- Zhe Wang
- Department of Vascular Surgery, First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Cheng Wang
- Department of Vascular Surgery, First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Fenghe Li
- Department of Vascular Surgery, First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Yu Zhao
- Department of Vascular Surgery, First Affiliated Hospital of Chongqing Medical University, Chongqing, China
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Salman HE, Ramazanli B, Yavuz MM, Yalcin HC. Biomechanical Investigation of Disturbed Hemodynamics-Induced Tissue Degeneration in Abdominal Aortic Aneurysms Using Computational and Experimental Techniques. Front Bioeng Biotechnol 2019; 7:111. [PMID: 31214581 PMCID: PMC6555197 DOI: 10.3389/fbioe.2019.00111] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2019] [Accepted: 05/02/2019] [Indexed: 11/13/2022] Open
Abstract
Abdominal aortic aneurysm (AAA) is the dilatation of the aorta beyond 50% of the normal vessel diameter. It is reported that 4-8% of men and 0.5-1% of women above 50 years of age bear an AAA and it accounts for ~15,000 deaths per year in the United States alone. If left untreated, AAA might gradually expand until rupture; the most catastrophic complication of the aneurysmal disease that is accompanied by a striking overall mortality of 80%. The precise mechanisms leading to AAA rupture remains unclear. Therefore, characterization of disturbed hemodynamics within AAAs will help to understand the mechanobiological development of the condition which will contribute to novel therapies for the condition. Due to geometrical complexities, it is challenging to directly quantify disturbed flows for AAAs clinically. Two other approaches for this investigation are computational modeling and experimental flow measurement. In computational modeling, the problem is first defined mathematically, and the solution is approximated with numerical techniques to get characteristics of flow. In experimental flow measurement, once the setup providing physiological flow pattern in a phantom geometry is constructed, velocity measurement system such as particle image velocimetry (PIV) enables characterization of the flow. We witness increasing number of applications of these complimentary approaches for AAA investigations in recent years. In this paper, we outline the details of computational modeling procedures and experimental settings and summarize important findings from recent studies, which will help researchers for AAA investigations and rupture mechanics.
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Affiliation(s)
| | - Burcu Ramazanli
- Department of Mechanical Engineering, Middle East Technical University, Ankara, Turkey
| | - Mehmet Metin Yavuz
- Department of Mechanical Engineering, Middle East Technical University, Ankara, Turkey
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Khannous F, Gaudry M, Guivier-Curien C, Piquet P, Deplano V. How can flow dynamics predict clinical evolution of residual type B aortic dissection? Comput Methods Biomech Biomed Engin 2019. [DOI: 10.1080/10255842.2020.1713495] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- F. Khannous
- Aix-Marseille Université, CNRS, Ecole Centrale, IRPHE UMR 7342, Marseille, France
| | - M. Gaudry
- Aix-Marseille Université, CNRS, Ecole Centrale, IRPHE UMR 7342, Marseille, France
- Aix-Marseille Université, APHM, Hôpital la Timone, Service de Chirurgie Vasculaire, Marseille, France
| | - C. Guivier-Curien
- Aix-Marseille Université, CNRS, Ecole Centrale, IRPHE UMR 7342, Marseille, France
| | - P. Piquet
- Aix-Marseille Université, APHM, Hôpital la Timone, Service de Chirurgie Vasculaire, Marseille, France
| | - V. Deplano
- Aix-Marseille Université, CNRS, Ecole Centrale, IRPHE UMR 7342, Marseille, France
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Liu C, Chen S, Sheng C, Ding P, Qian Z, Ren L. The art of a hydraulic joint in a spider’s leg: modelling, computational fluid dynamics (CFD) simulation, and bio-inspired design. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2019; 205:491-504. [DOI: 10.1007/s00359-019-01336-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Revised: 03/28/2019] [Accepted: 04/01/2019] [Indexed: 10/26/2022]
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Overeem SP, de Vries JPPM, Boersen JT, Slump CH, Reijnen MMPJ, Versluis M, Groot Jebbink E. Haemodynamics in Different Flow Lumen Configurations of Customised Aortic Repair for Infrarenal Aortic Aneurysms. Eur J Vasc Endovasc Surg 2019; 57:709-718. [PMID: 31000458 DOI: 10.1016/j.ejvs.2018.11.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Accepted: 11/20/2018] [Indexed: 11/25/2022]
Abstract
OBJECTIVE Customised aortic repair (CAR) is a new and minimally invasive technique for the endovascular treatment of abdominal aortic aneurysms (AAAs). The aneurysm is completely sealed with a non-contained, non-cross linked polymer, while a new flow lumen is created with balloons. For CAR, the haemodynamically most favourable balloon and flow lumen configuration has not been established before; therefore, four flow parameters were assessed in an in vitro model. METHODS Three in vitro balloon configurations were implanted in an in vitro AAA model; a configuration with crossing balloons (CC) and two parallel configurations (PC1 and PC2). These three models were consecutively placed in a flow system that mimics physiological flow conditions. Laser particle imaging velocimetry (PIV) was used to resolve spatial and temporal flow patterns during the cardiac cycle. In house built algorithms were used to analyse the PIV data for the computing of (i) flow velocity; (ii) vorticity; (iii) wall shear stress (WSS); and (iv) time averaged wall shear stress (TAWSS). RESULTS Suprarenal flow patterns were similar in all models. The CC showed a higher infrarenal velocity than PC1 and PC2 (38 cm/s vs. 23 cm/s vs. 23 cm/s), and a higher vorticity at the crossing of the lumens (CC: 337/s; PC1 127/s; PC2: 112/s). The lowest vorticity was observed in PC2, especially in the infrarenal neck (CC: 200/s; PC1 164/s; PC2: 98/s). Although WSS and TAWSS varied between configurations, values were in the within non-pathological range. CONCLUSION The flow lumens created by three balloon configurations used in an in vitro model of CAR have been studied, and resulted in different haemodynamics. The differences in velocity and lower vorticity, especially at the crossing section of the two balloons, showed that PC2 has favourable haemodynamics compared with the CC and PC1. Future research will be focused on the clinical applicability of CAR based on the PC2 design.
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Affiliation(s)
- Simon P Overeem
- Department of Vascular Surgery, St. Antonius Hospital, Nieuwegein, the Netherlands; Multimodality Medical Imaging M3i Group, Technical Medical Centre, University of Twente, the Netherlands.
| | - Jean-Paul P M de Vries
- Division of Surgery, Department of Vascular Surgery, University Medical Centre Groningen, Groningen, the Netherlands
| | - Jorrit T Boersen
- Department of Vascular Surgery, St. Antonius Hospital, Nieuwegein, the Netherlands
| | - Cornelis H Slump
- Robotics and Mechatronics, Technical Medical Centre, University of Twente, Enschede, the Netherlands
| | - Michel M P J Reijnen
- Multimodality Medical Imaging M3i Group, Technical Medical Centre, University of Twente, the Netherlands; Department of Vascular Surgery, Rijnstate Hospital, Arnhem, the Netherlands
| | - Michel Versluis
- Multimodality Medical Imaging M3i Group, Technical Medical Centre, University of Twente, the Netherlands; Physics of Fluids Group, University of Twente, Enschede, the Netherlands
| | - Erik Groot Jebbink
- Multimodality Medical Imaging M3i Group, Technical Medical Centre, University of Twente, the Netherlands
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Raptis A, Xenos M, Kouvelos G, Giannoukas A, Matsagkas M. Haemodynamic performance of AFX and Nellix endografts: a computational fluid dynamics study. Interact Cardiovasc Thorac Surg 2019; 26:826-833. [PMID: 29325136 DOI: 10.1093/icvts/ivx414] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Accepted: 12/03/2017] [Indexed: 11/14/2022] Open
Abstract
OBJECTIVES The objective of this study is to analyse the flow conditions in the AFX and Nellix endografts (EGs) accounting for their postimplantation configuration in patients with an endovascular aneurysm repair-treated abdominal aortic aneurysm. METHODS We reconstructed post-endovascular aneurysm repair computed tomography scans of patients treated with an AFX or Nellix EG creating post-implantation EG models. We examined 16 patients, 8 in each group. The blood flow properties were obtained by computational fluid dynamics simulations and were subsequently compared with physiological infrarenal blood flow properties measured in 5 healthy subjects. Specifically, pressure drop, maximum velocity and wall shear stress were measured at peak systole and mean helicity at mid-diastole. RESULTS Our statistical analyses showed that the haemodynamic properties in both control regions did not vary statistically after the implantation of either the AFX or the Nellix EG, except for helicity that was significantly lower in the abdominal part of the Nellix EG compared with the expected physiological measurement. Regardless of the overall blood flow restoration, it is important to note that low pressure drop was detected along the limbs of the AFX and suppressed blood helical motion was detected at the entrance of the Nellix device. CONCLUSIONS It is observed from the results that the AFX EG has achieved absolute restoration of blood flow after endovascular aneurysm repair, although the development of secondary flow in the upper part of the EG and the low pressure drop in its limbs should be acknowledged. The Nellix EG also seems to be haemodynamically efficient. However, the suppression of helical flow before blood enters the device might raise concerns about its clinical application.
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Affiliation(s)
- Anastasios Raptis
- Laboratory for Vascular Simulations, Institute of Vascular Diseases, Ioannina, Greece
| | - Michalis Xenos
- Laboratory for Vascular Simulations, Institute of Vascular Diseases, Ioannina, Greece.,Department of Mathematics, University of Ioannina, Ioannina, Greece
| | - George Kouvelos
- Department of Vascular Surgery, Faculty of Medicine, University of Thessaly, Larissa, Greece
| | - Athanasios Giannoukas
- Laboratory for Vascular Simulations, Institute of Vascular Diseases, Ioannina, Greece.,Department of Vascular Surgery, Faculty of Medicine, University of Thessaly, Larissa, Greece
| | - Miltiadis Matsagkas
- Laboratory for Vascular Simulations, Institute of Vascular Diseases, Ioannina, Greece.,Department of Vascular Surgery, Faculty of Medicine, University of Thessaly, Larissa, Greece
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Domonkos A, Staffa R, Kubíček L. Effect of intraluminal thrombus on growth rate of abdominal aortic aneurysms. INT ANGIOL 2019; 38:39-45. [DOI: 10.23736/s0392-9590.18.04006-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Arzani A. Accounting for residence-time in blood rheology models: do we really need non-Newtonian blood flow modelling in large arteries? J R Soc Interface 2018; 15:rsif.2018.0486. [PMID: 30257924 DOI: 10.1098/rsif.2018.0486] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Accepted: 09/03/2018] [Indexed: 12/27/2022] Open
Abstract
Patient-specific computational fluid dynamics (CFD) is a promising tool that provides highly resolved haemodynamics information. The choice of blood rheology is an assumption in CFD models that has been subject to extensive debate. Blood is known to exhibit shear-thinning behaviour, and non-Newtonian modelling has been recommended for aneurysmal flows. Current non-Newtonian models ignore rouleaux formation, which is the key player in blood's shear-thinning behaviour. Experimental data suggest that red blood cell aggregation and rouleaux formation require notable red blood cell residence-time (RT) in a low shear rate regime. This study proposes a novel hybrid Newtonian and non-Newtonian rheology model where the shear-thinning behaviour is activated in high RT regions based on experimental data. Image-based abdominal aortic and cerebral aneurysm models are considered and highly resolved CFD simulations are performed using a minimally dissipative solver. Lagrangian particle tracking is used to define a backward particle RT measure and detect stagnant regions with increased rouleaux formation likelihood. Our novel RT-based non-Newtonian model shows a significant reduction in shear-thinning effects and provides haemodynamic results qualitatively identical and quantitatively close to the Newtonian model. Our results have important implications in patient-specific CFD modelling and suggest that non-Newtonian models should be revisited in large artery flows.
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Affiliation(s)
- Amirhossein Arzani
- Department of Mechanical Engineering, Northern Arizona University, Flagstaff, AZ, USA
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Strongly Coupled Morphological Features of Aortic Aneurysms Drive Intraluminal Thrombus. Sci Rep 2018; 8:13273. [PMID: 30185838 PMCID: PMC6125404 DOI: 10.1038/s41598-018-31637-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Accepted: 08/15/2018] [Indexed: 01/13/2023] Open
Abstract
Over 75% of abdominal aortic aneurysms harbor an intraluminal thrombus, and increasing evidence suggests that biologically active thrombus contributes to the natural history of these potentially lethal lesions. Thrombus formation depends on the local hemodynamics, which in turn depends on morphological features of the aneurysm and near vasculature. We previously presented a hemodynamically motivated “thrombus formation potential” that predicts where and when thrombus might form. Herein, we combine detailed studies of the three-dimensional hemodynamics with methods of sparse grid collocation and interpolation via kriging to examine roles of five key morphological features of aneurysms on thrombus formation: lesion diameter, axial position, length, curvature, and renal artery position. Computational simulations suggest that maximum diameter is a key determinant of thrombogenicity, but other morphological features modulate this dependence. More distally located lesions tend to have a higher thrombus formation potential and shorter lesions tend to have a higher potential than longer lesions, given the same aneurysmal dilatation. Finally, movement of vortical structures through the infrarenal aorta and lesion can significantly affect thrombogenicity. Formation of intraluminal thrombus within an evolving abdominal aortic aneurysm thus depends on coupled morphological features, not all intuitive, and computational simulations can be useful for predicting thrombogenesis.
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