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Wang Y, Zhou C, Wu X, Liu L, Deng L. Haemodynamic effects of non-Newtonian fluid blood on the abdominal aorta before and after double tear rupture. Med Eng Phys 2024; 130:104205. [PMID: 39160029 DOI: 10.1016/j.medengphy.2024.104205] [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: 12/14/2023] [Revised: 04/30/2024] [Accepted: 07/01/2024] [Indexed: 08/21/2024]
Abstract
OBJECTIVES Intimal tears caused by aortic dissection can weaken the arterial wall and lead to aortic aneurysms. However, the effect of different tear states on the blood flow behaviour remains complex. This study uses a novel approach that combines numerical haemodynamic simulation with in vitro experiments to elucidate the effect of arterial dissection rupture on the complex blood flow state within the abdominal aneurysm and the endogenous causes of end-organ malperfusion. MATERIALS AND METHODS Based on the CT imaging data and clinical physiological parameters, the overall arterial models including aortic dissection and aneurysm with single tear and double tear were established, and the turbulence behaviours and haemodynamic characteristics of arterial dissection and aneurysm under different blood pressures were simulated by using non-Newtonian flow fluids with the pulsatile blood flow rate of the clinical patients as a cycle, and the results of the numerical simulation were verified by in vitro simulation experiments. RESULTS Hemodynamic simulations revealed that the aneurysm and single-tear false lumen generated a maximum pressure of 320.591 mmHg, 267 % over the 120 mmHg criterion. The pressure differential generates reflux, leading to a WSS of 2247.9 Pa at the TL inlet and blood flow velocities of up to 6.41 m/s inducing extend of the inlet. DTD Medium FL instantaneous WP above 120 mmHg Standard 151 % Additionally, there was 82.5 % higher flow in the right iliac aorta than in the left iliac aorta, which triggered malperfusion. Thrombus was accumulated distal to the tear and turbulence. These results are consistent with the findings of the in vitro experiments. CONCLUSIONS This study reveals the haemodynamic mechanisms by which aortic dissection induces aortic aneurysms to produce different risk states. This will contribute to in vitro simulation studies as a new fulcrum in the process of moving from numerical simulation to clinical trials.
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Affiliation(s)
- Yiwen Wang
- Key Laboratory of Advanced Manufacturing and Intelligent Technology, Ministry of Education, Harbin University of Science and Technology, Harbin, 150080, China.
| | - Changli Zhou
- Key Laboratory of Advanced Manufacturing and Intelligent Technology, Ministry of Education, Harbin University of Science and Technology, Harbin, 150080, China
| | - Xuefeng Wu
- Key Laboratory of Advanced Manufacturing and Intelligent Technology, Ministry of Education, Harbin University of Science and Technology, Harbin, 150080, China
| | - Lijia Liu
- Key Laboratory of Advanced Manufacturing and Intelligent Technology, Ministry of Education, Harbin University of Science and Technology, Harbin, 150080, China
| | - Li Deng
- Department of Cardiovascular Surgery, First Affiliated Hospital of Harbin Medical University, Harbin, 150086, China
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2
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Yeerella RH, Cai S. Fracture mechanics modeling of aortic dissection. Biomech Model Mechanobiol 2024; 23:1377-1391. [PMID: 38658479 PMCID: PMC11341663 DOI: 10.1007/s10237-024-01845-3] [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: 02/15/2024] [Accepted: 03/29/2024] [Indexed: 04/26/2024]
Abstract
Aortic dissection, a critical cardiovascular condition with life-threatening implications, is distinguished by the development of a tear and its propagation within the aortic wall. A thorough understanding of the initiation and progression of these tears, or cracks, is essential for accurate diagnosis and effective treatment. This paper undertakes a fracture mechanics approach to delve into the mechanics of tear propagation in aortic dissection. Our objective is to elucidate the impact of geometric and material parameters, providing valuable insights into the determinants of this pivotal cardiovascular event. Through our investigation, we have gained an understanding of how various parameters influence the energy release rate for tear propagation in both longitudinal and circumferential directions, aligning our findings with clinical data.
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Affiliation(s)
- Ram Hemanth Yeerella
- Department of Mechanical and Aerospace Engineering, University of California San Diego, 9500 Gilman Dr, La Jolla, CA, 92093, USA
| | - Shengqiang Cai
- Department of Mechanical and Aerospace Engineering, University of California San Diego, 9500 Gilman Dr, La Jolla, CA, 92093, USA.
- Program in Materials Science and Engineering, University of California San Diego, 9500 Gilman Dr, La Jolla, CA, 92093, USA.
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3
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Forneris A, Hassanabad AF, Appoo JJ, Di Martino ES. Predicting Aneurysmal Degeneration in Uncomplicated Residual Type B Aortic Dissection. Bioengineering (Basel) 2024; 11:690. [PMID: 39061772 PMCID: PMC11274148 DOI: 10.3390/bioengineering11070690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2024] [Revised: 06/18/2024] [Accepted: 06/19/2024] [Indexed: 07/28/2024] Open
Abstract
The formation of an aneurysm in the false lumen (FL) is a long-term complication in a significant percentage of type B aortic dissection (AD) patients. The ability to predict which patients are likely to progress to aneurysm formation is key to justifying the risks of interventional therapy. The investigation of patient-specific hemodynamics has the potential to enable a patient-tailored approach to improve prognosis by guiding disease management for type B dissection. CFD-derived hemodynamic descriptors and geometric features were used to retrospectively assess individual aortas for a population of residual type B AD patients and analyze correlations with known outcomes (i.e., rapid aortic growth, death). The results highlight great variability in flow patterns and hemodynamic descriptors. A rapid aortic expansion was found to be associated with a larger FL. Time-averaged wall shear stress at the tear region emerged as a possible indicator of the dynamics of flow exchange between lumens and its effect on the evolution of individual aortas. High FL flow rate and tortuosity were associated with adverse outcomes suggesting a role as indicators of risk. AD induces complex changes in vessel geometry and hemodynamics. The reported findings emphasize the need for a patient-tailored approach when evaluating uncomplicated type B AD patients and show the potential of CFD-derived hemodynamics to complement anatomical assessment and help disease management.
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Affiliation(s)
- Arianna Forneris
- Department of Biomedical Engineering, Schulich School of Engineering, University of Calgary, Calgary, AB T2N 1N4, Canada;
- R&D Department, ViTAA Medical Solutions, Montreal, QC H2K 1M6, Canada
| | - Ali F. Hassanabad
- Section of Cardiac Surgery, Department of Cardiac Sciences, Libin Cardiovascular Institute, University of Calgary, Calgary, AB T2N 1N4, Canada; (A.F.H.); (J.J.A.)
| | - Jehangir J. Appoo
- Section of Cardiac Surgery, Department of Cardiac Sciences, Libin Cardiovascular Institute, University of Calgary, Calgary, AB T2N 1N4, Canada; (A.F.H.); (J.J.A.)
| | - Elena S. Di Martino
- Department of Biomedical Engineering, Schulich School of Engineering, University of Calgary, Calgary, AB T2N 1N4, Canada;
- R&D Department, ViTAA Medical Solutions, Montreal, QC H2K 1M6, Canada
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4
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Deus J, Martin E. Efficient Cardiovascular Parameters Estimation for Fluid-Structure Simulations Using Gappy Proper Orthogonal Decomposition. Ann Biomed Eng 2024:10.1007/s10439-024-03568-z. [PMID: 38969956 DOI: 10.1007/s10439-024-03568-z] [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: 12/22/2023] [Accepted: 06/21/2024] [Indexed: 07/07/2024]
Abstract
As full-scale detailed hemodynamic simulations of the entire vasculature are not feasible, numerical analysis should be focused on specific regions of the cardiovascular system, which requires the identification of lumped parameters to represent the patient behavior outside the simulated computational domain. We present a novel technique for estimating cardiovascular model parameters using gappy Proper Orthogonal Decomposition (g-POD). A POD basis is constructed with FSI simulations for different values of the lumped model parameters, and a linear operator is applied to retain information that can be compared to the available patient measurements. Then, the POD coefficients of the reconstructed solution are computed either by projecting patient measurements or by solving a minimization problem with constraints. The POD reconstruction is then used to estimate the model parameters. In the first test case, the parameter values of a 3-element Windkessel model are approximated using artificial patient measurements, obtaining a relative error of less than 4.2%. In the second case, 4 sets of 3-element Windkessel are approximated in a patient's aorta geometry, resulting in an error of less than 8% for the flow and less than 5% for the pressure. The method shows accurate results even with noisy patient data. It automatically calculates the delay between measurements and simulations and has flexibility in the types of patient measurements that can handle (at specific points, spatial or time averaged). The method is easy to implement and can be used in simulations performed in general-purpose FSI software.
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Affiliation(s)
- J Deus
- Departamento de Ingeniería Mecánica, Máquinas y Motores Térmicos y Fluidos, Universidade de Vigo, Campus Marcosende, 36310, Vigo, Spain
| | - E Martin
- Departamento de Ingeniería Mecánica, Máquinas y Motores Térmicos y Fluidos, Universidade de Vigo, Campus Marcosende, 36310, Vigo, Spain.
- Instituto de Física y Ciencias Aeroespaciales (IFCAE), Universidade de Vigo, Campus de As Lagoas, 32004, Ourense, Spain.
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5
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Liu B, Zhao J, Chen X, Fang K, Yang W, Zhang X, Shu C. Hemodynamic analysis of unilateral and bilateral renal artery stenosis based on fluid-structure interaction. Comput Methods Biomech Biomed Engin 2023:1-12. [PMID: 38009048 DOI: 10.1080/10255842.2023.2282949] [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: 07/27/2023] [Accepted: 11/07/2023] [Indexed: 11/28/2023]
Abstract
Renal artery stenosis (RAS) hypertension is a common type of secondary hypertension. This paper aimed to explore how unilateral renal artery stenosis (Uni-RAS) and bilateral renal artery stenosis (Bi-RAS) caused renovascular hypertension with the fluid-structure interaction (FSI) method. Based on a real RAS model, 20 ideal models with different stenosis degrees were established by modifying the stenosis segment. The hemodynamic parameters at different degrees of stenosis, mass flow rate (MFR), pressure drop (PD), fractional flow reserve (FFR), oscillatory shear index (OSI), and relative residence time (RRT), were numerically calculated by the computational fluid dynamics (CFD) method. The numerical results showed that RAS caused the decrease of MFR, and the increase of PD and the proportion of high OSI and high RRT. In the case of RAS, it could not be regarded as a reference indicator for causing renovascular hypertension that the value of FFR was greater than 0.9. In addition, the results of the statistical analysis indicated that Uni-RAS and Bi-RAS were statistically different for MFR, PD and the proportion of high RRT.
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Affiliation(s)
- Bingxin Liu
- School of Mathematics and Physics, University of Science and Technology Beijing, Beijing, China
| | - Jiawei Zhao
- Department of Vascular Surgery, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Xuehui Chen
- School of Mathematics and Physics, University of Science and Technology Beijing, Beijing, 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, China
| | - Weidong Yang
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, China
| | - Xuelan Zhang
- School of Mathematics and Physics, University of Science and Technology Beijing, Beijing, 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, China
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6
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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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7
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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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8
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Dadras R, Jabbari A, Asl NK, Soltani M, Rafiee F, Parsaee M, Golchin S, Pouraliakbar H, Sadeghipour P, Alimohammadi M. In-silico investigations of haemodynamic parameters for a blunt thoracic aortic injury case. Sci Rep 2023; 13:8355. [PMID: 37221220 DOI: 10.1038/s41598-023-35585-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2023] [Accepted: 05/20/2023] [Indexed: 05/25/2023] Open
Abstract
Accounting for 1.5% of thoracic trauma, blunt thoracic aortic injury (BTAI) is a rare disease with a high mortality rate that nowadays is treated mostly via thoracic endovascular aortic repair (TEVAR). Personalised computational models based on fluid-solid interaction (FSI) principals not only support clinical researchers in studying virtual therapy response, but also are capable of predicting eventual outcomes. The present work studies the variation of key haemodynamic parameters in a clinical case of BTAI after successful TEVAR, using a two-way FSI model. The three-dimensional (3D) patient-specific geometries of the patient were coupled with three-element Windkessel model for both prior and post intervention cases, forcing a correct prediction of blood flow over each section. Results showed significant improvement in velocity and pressure distribution after stenting. High oscillatory, low magnitude shear (HOLMES) regions require careful examination in future follow-ups, since thrombus formation was confirmed in some previously clinically reported cases of BTAI treated with TEVAR. The strength of swirling flows along aorta was also damped after stent deployment. Highlighting the importance of haemodynamic parameters in case-specific therapies. In future studies, compromising motion of aortic wall due to excessive cost of FSI simulations can be considered and should be based on the objectives of studies to achieve a more clinical-friendly patient-specific CFD model.
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Affiliation(s)
- Rezvan Dadras
- Department of Mechanical Engineering, K. N. Toosi Univeristy of Technology, Tehran, Iran.
| | - Alireza Jabbari
- Department of Mechanical Engineering, K. N. Toosi Univeristy of Technology, Tehran, Iran
| | - Narges Kamaei Asl
- Department of Mechanical Engineering, K. N. Toosi Univeristy of Technology, Tehran, Iran
| | - Madjid Soltani
- Department of Mechanical Engineering, K. N. Toosi Univeristy of Technology, Tehran, Iran
| | - Farnaz Rafiee
- Rajaie Cardiovascular, Medical, and Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Mozhgan Parsaee
- Rajaie Cardiovascular, Medical, and Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Shadi Golchin
- Rajaie Cardiovascular, Medical, and Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Hamidreza Pouraliakbar
- Rajaie Cardiovascular, Medical, and Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Parham Sadeghipour
- Rajaie Cardiovascular, Medical, and Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Mona Alimohammadi
- Department of Mechanical Engineering, K. N. Toosi Univeristy of Technology, Tehran, Iran.
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9
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Black SM, Maclean C, Hall Barrientos P, Ritos K, McQueen A, Kazakidi A. Calibration of patient-specific boundary conditions for coupled CFD models of the aorta derived from 4D Flow-MRI. Front Bioeng Biotechnol 2023; 11:1178483. [PMID: 37251565 PMCID: PMC10210162 DOI: 10.3389/fbioe.2023.1178483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Accepted: 04/21/2023] [Indexed: 05/31/2023] Open
Abstract
Introduction: Patient-specific computational fluid dynamics (CFD) models permit analysis of complex intra-aortic hemodynamics in patients with aortic dissection (AD), where vessel morphology and disease severity are highly individualized. The simulated blood flow regime within these models is sensitive to the prescribed boundary conditions (BCs), so accurate BC selection is fundamental to achieve clinically relevant results. Methods: This study presents a novel reduced-order computational framework for the iterative flow-based calibration of 3-Element Windkessel Model (3EWM) parameters to generate patient-specific BCs. These parameters were calibrated using time-resolved flow information derived from retrospective four-dimensional flow magnetic resonance imaging (4D Flow-MRI). For a healthy and dissected case, blood flow was then investigated numerically in a fully coupled zero dimensional-three dimensional (0D-3D) numerical framework, where the vessel geometries were reconstructed from medical images. Calibration of the 3EWM parameters was automated and required ~3.5 min per branch. Results: With prescription of the calibrated BCs, the computed near-wall hemodynamics (time-averaged wall shear stress, oscillatory shear index) and perfusion distribution were consistent with clinical measurements and previous literature, yielding physiologically relevant results. BC calibration was particularly important in the AD case, where the complex flow regime was captured only after BC calibration. Discussion: This calibration methodology can therefore be applied in clinical cases where branch flow rates are known, for example, via 4D Flow-MRI or ultrasound, to generate patient-specific BCs for CFD models. It is then possible to elucidate, on a case-by-case basis, the highly individualized hemodynamics which occur due to geometric variations in aortic pathology high spatiotemporal resolution through CFD.
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Affiliation(s)
- Scott MacDonald Black
- Department of Biomedical Engineering, University of Strathclyde, Glasgow, United Kingdom
| | - Craig Maclean
- Research and Development, Terumo Aortic, Glasgow, United Kingdom
| | - Pauline Hall Barrientos
- Clinical Physics, Queen Elizabeth University Hospital, NHS Greater Glasgow and Clyde, Glasgow, United Kingdom
| | - Konstantinos Ritos
- Department of Mechanical and Aerospace Engineering, University of Strathclyde, Glasgow, United Kingdom
- Department of Mechanical Engineering, University of Thessaly, Volos, Greece
| | - Alistair McQueen
- Department of Biomedical Engineering, University of Glasgow, Glasgow, United Kingdom
| | - Asimina Kazakidi
- Department of Biomedical Engineering, University of Strathclyde, Glasgow, United Kingdom
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10
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Zhu Y, Xu XY, Rosendahl U, Pepper J, Mirsadraee S. Advanced risk prediction for aortic dissection patients using imaging-based computational flow analysis. Clin Radiol 2023; 78:e155-e165. [PMID: 36610929 DOI: 10.1016/j.crad.2022.12.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Revised: 11/28/2022] [Accepted: 12/02/2022] [Indexed: 12/24/2022]
Abstract
Patients with either a repaired or medically managed aortic dissection have varying degrees of risk of developing late complications. High-risk patients would benefit from earlier intervention to improve their long-term survival. Currently serial imaging is used for risk stratification, which is not always reliable. On the other hand, understanding aortic haemodynamics within a dissection is essential to fully evaluate the disease and predict how it may progress. In recent decades, computational fluid dynamics (CFD) has been extensively applied to simulate complex haemodynamics within aortic diseases, and more recently, four-dimensional (4D)-flow magnetic resonance imaging (MRI) techniques have been developed for in vivo haemodynamic measurement. This paper presents a comprehensive review on the application of image-based CFD simulations and 4D-flow MRI analysis for risk prediction in aortic dissection. The key steps involved in patient-specific CFD analyses are demonstrated. Finally, we propose a workflow incorporating computational modelling for personalised assessment to aid in risk stratification and treatment decision-making.
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Affiliation(s)
- Y Zhu
- Department of Chemical Engineering, Imperial College London, London, UK
| | - X Y Xu
- Department of Chemical Engineering, Imperial College London, London, UK
| | - U Rosendahl
- Department of Cardiac Surgery, Royal Brompton and Harefield Hospitals, London, UK; National Heart and Lung Institute, Imperial College London, London, UK
| | - J Pepper
- Department of Cardiac Surgery, Royal Brompton and Harefield Hospitals, London, UK; National Heart and Lung Institute, Imperial College London, London, UK
| | - S Mirsadraee
- National Heart and Lung Institute, Imperial College London, London, UK; Department of Radiology, Royal Brompton and Harefield Hospitals, London, UK.
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11
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Li D, Wang J, Zeng W, Zeng X, Liu Z, Cao H, Yuan D, Zheng T. The loss of helical flow in the thoracic aorta might be an identifying marker for the risk of acute type B aortic dissection. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2023; 230:107331. [PMID: 36621070 DOI: 10.1016/j.cmpb.2022.107331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Revised: 12/06/2022] [Accepted: 12/29/2022] [Indexed: 06/17/2023]
Abstract
BACKGROUND AND OBJECTIVE The occurrence of acute type B aortic dissection (TBAD) remained unclear. This study aimed to investigate the association between flow features and hemodynamic parameters in aortas that demonstrated the risk of TBAD occurrence. METHODS The geometries of 15 hyperacute TBAD and 12 control patients (with healthy aorta) were reconstructed from computed tomography angiography images. Pre-TBAD models were then obtained by eliminating the dissection flaps. Flow features and hemodynamic parameters, including wall shear stress-related parameters and helicities, were compared between pre-TBAD and control models using computational fluid dynamics. RESULTS There were no significant differences in baseline characteristics and anatomical parameters between the two groups. Significant contralateral helical blood flow was present in the healthy thoracic aorta, while almost no helical flow was observed in the pre-TBAD group. In addition, the mean normal transverse wall shear stress (NtransWSS) was significantly higher in the pre-TBAD group (aortic arch 0.49±0.09 vs. 0.40±0.05, P = 0.04; descending aorta: 0.46±0.05 vs. 0.33±0.02, P<0.01). Moreover, a significantly negative correlation was found between helicity and NtransWSS in the descending aorta. Moreover, the location of primary tears in 12 pre-TABD subjects matched well with regions of high NtransWSS. CONCLUSIONS Loss of helical flow in the aortic arch and descending aorta may be a major flow feature in patients with underlying TBAD, resulting in increased flow disturbance and wall lesions.
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Affiliation(s)
- Da Li
- Department of Applied Mechanics, Sichuan University, No.24 South Section 1, Chengdu 610065, China; Yibin Institute of Industrial Technology, Sichuan University Yibin Park, Yibin, China
| | - Jiarong Wang
- Division of Vascular Surgery, Department of General Surgery, West China Hospital, Sichuan University, No. 37 Guo Xue Xiang, Chengdu 610041, China
| | - Wen Zeng
- Division of radiology, West China Hospital, Sichuan University, Chengdu, China
| | - Xiangguo Zeng
- Department of Applied Mechanics, Sichuan University, No.24 South Section 1, Chengdu 610065, China
| | - Zhan Liu
- Department of Applied Mechanics, Sichuan University, No.24 South Section 1, Chengdu 610065, China; Yibin Institute of Industrial Technology, Sichuan University Yibin Park, Yibin, China
| | - Haoyao Cao
- Department of Applied Mechanics, Sichuan University, No.24 South Section 1, Chengdu 610065, China; Yibin Institute of Industrial Technology, Sichuan University Yibin Park, Yibin, China
| | - Ding Yuan
- Division of Vascular Surgery, Department of General Surgery, West China Hospital, Sichuan University, No. 37 Guo Xue Xiang, Chengdu 610041, China; Med-X center for informatics, Sichuan University, Chengdu, China.
| | - Tinghui Zheng
- Department of Applied Mechanics, Sichuan University, No.24 South Section 1, Chengdu 610065, China; Yibin Institute of Industrial Technology, Sichuan University Yibin Park, Yibin, China; Med-X center for informatics, Sichuan University, Chengdu, China.
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12
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Tricarico R, Berceli SA, Tran-Son-Tay R, He Y. Non-invasive estimation of the parameters of a three-element windkessel model of aortic arch arteries in patients undergoing thoracic endovascular aortic repair. Front Bioeng Biotechnol 2023; 11:1127855. [PMID: 36926690 PMCID: PMC10011467 DOI: 10.3389/fbioe.2023.1127855] [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: 12/20/2022] [Accepted: 02/17/2023] [Indexed: 03/08/2023] Open
Abstract
Background: Image-based computational hemodynamic modeling and simulations are important for personalized diagnosis and treatment of cardiovascular diseases. However, the required patient-specific boundary conditions are often not available and need to be estimated. Methods: We propose a pipeline for estimating the parameters of the popular three-element Windkessel (WK3) models (a proximal resistor in series with a parallel combination of a distal resistor and a capacitor) of the aortic arch arteries in patients receiving thoracic endovascular aortic repair of aneurysms. Pre-operative and post-operative 1-week duplex ultrasound scans were performed to obtain blood flow rates, and intra-operative pressure measurements were also performed invasively using a pressure transducer pre- and post-stent graft deployment in arch arteries. The patient-specific WK3 model parameters were derived from the flow rate and pressure waveforms using an optimization algorithm reducing the error between simulated and measured pressure data. The resistors were normalized by total resistance, and the capacitor was normalized by total resistance and heart rate. The normalized WK3 parameters can be combined with readily available vessel diameter, brachial blood pressure, and heart rate data to estimate WK3 parameters of other patients non-invasively. Results: Ten patients were studied. The medians (interquartile range) of the normalized proximal resistor, distal resistor, and capacitor parameters are 0.10 (0.07-0.15), 0.90 (0.84-0.93), and 0.46 (0.33-0.58), respectively, for common carotid artery; 0.03 (0.02-0.04), 0.97 (0.96-0.98), and 1.91 (1.63-2.26) for subclavian artery; 0.18 (0.08-0.41), 0.82 (0.59-0.92), and 0.47 (0.32-0.85) for vertebral artery. The estimated pressure showed fairly high tolerance to patient-specific inlet flow rate waveforms using the WK3 parameters estimated from the medians of the normalized parameters. Conclusion: When patient-specific outflow boundary conditions are not available, our proposed pipeline can be used to estimate the WK3 parameters of arch arteries.
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Affiliation(s)
- Rosamaria Tricarico
- Department of Biomedical Engineering, University of Florida, Gainesville, FL, United States
| | - Scott A Berceli
- Division of Vascular Surgery and Endovascular Therapy, Department of Surgery, University of Florida, Gainesville, FL, United States.,North Florida/South Georgia Veterans Health System, Gainesville, FL, United States
| | - Roger Tran-Son-Tay
- Department of Biomedical Engineering, University of Florida, Gainesville, FL, United States.,Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, FL, United States
| | - Yong He
- Division of Vascular Surgery and Endovascular Therapy, Department of Surgery, University of Florida, Gainesville, FL, United States
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Liu D, Wang X, Zhao D, Sun Z, Biekan J, Wen Z, Xu L, Liu J. Influence of MRI-based boundary conditions on type B aortic dissection simulations in false lumen with or without abdominal aorta involvement. Front Physiol 2022; 13:977275. [PMID: 36160847 PMCID: PMC9490059 DOI: 10.3389/fphys.2022.977275] [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: 06/24/2022] [Accepted: 08/15/2022] [Indexed: 11/13/2022] Open
Abstract
Most computational hemodynamic studies of aortic dissections rely on idealized or general boundary conditions. However, numerical simulations that ignore the characteristics of the abdominal branch arteries may not be conducive to accurately observing the hemodynamic changes below the branch arteries. In the present study, two men (M-I and M-II) with type B aortic dissection (TBAD) underwent arterial-phase computed tomography angiography and four-dimensional flow magnetic resonance imaging (MRI) before and after thoracic endovascular aortic repair (TEVAR). The finite element method was used to simulate the computational fluid dynamic parameters of TBAD [false lumen (FL) with or without visceral artery involvement] under MRI-specific and three idealized boundary conditions in one cardiac cycle. Compared to the results of zero pressure and outflow boundary conditions, the simulations with MRI boundary conditions were closer to the initial MRI data. The pressure difference between true lumen and FL after TEVAR under the other three boundary conditions was lower than that of the MRI-specific results. The results of the outflow boundary conditions could not characterize the effect of the increased wall pressure near the left renal artery caused by the impact of Tear-1, which raised concerns about the distal organ and limb perfused by FL. After TEVAR, the flow velocity and wall pressure in the FL and the distribution areas of high time average wall shear stress and oscillating shear index were reduced. The difference between the calculation results for different boundary conditions was lower in M-II, wherein FL did not involve the abdominal aorta branches than in M-I. The boundary conditions of the abdominal branch arteries from MRI data might be valuable in elucidating the hemodynamic changes of the descending aorta in TBAD patients before and after treatment, especially those with FL involving the branch arteries.
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Affiliation(s)
- Dongting Liu
- Department of Radiology, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
| | - Xuan Wang
- Department of Mechanics and Engineering Science, College of Engineering, Peking University, Beijing, China
| | - Dongliang Zhao
- Department of Mechanics and Engineering Science, College of Engineering, Peking University, Beijing, China
| | - Zhonghua Sun
- Discipline of Medical Radiation Science, Curtin Medical School, Curtin University, Perth, WA, Australia
- *Correspondence: Jiayi Liu, ; Zhonghua Sun,
| | | | - Zhaoying Wen
- Department of Radiology, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
| | - Lei Xu
- Department of Radiology, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
| | - Jiayi Liu
- Department of Radiology, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
- *Correspondence: Jiayi Liu, ; Zhonghua Sun,
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14
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Ling Y, Schenkel T, Tang J, Liu H. Computational fluid dynamics investigation on aortic hemodynamics in double aortic arch before and after ligation surgery. J Biomech 2022; 141:111231. [PMID: 35901663 DOI: 10.1016/j.jbiomech.2022.111231] [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: 02/24/2022] [Revised: 07/15/2022] [Accepted: 07/18/2022] [Indexed: 02/08/2023]
Abstract
Double aortic arch (DAA) malformation is one of the reasons for symptomatic vascular rings, the hemodynamics of which is still poorly understood. This study aims to investigate the blood flow characteristics in patient-specific double aortic arches using computational fluid dynamics (CFD). Seven cases of infantile patients with DAA were collected and their computed tomography images were used to reconstruct 3D computational models. A modified Carreau model was used to consider the non-Newtonian effect of blood and a three-element Windkessel model taking the effect of the age of patients into account was applied to reproduce physiological pressure waveforms. Numerical results show that blood flow distribution and energy loss of DAA depends on relative sizes of the two aortic arches and their angles with the ascending aorta. Ligation of either aortic arch increases the energy loss of blood in the DAA, leading to the increase in cardiac workload. Generally, the rising rate of energy loss before and after the surgery is almost linear with the area ratio between the aortic arch without ligation and the ascending aorta.
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Affiliation(s)
- Yunfei Ling
- Department of Cardiovascular Surgery, West China Hospital, Sichuan University, Chengdu 610041, China; State Key Laboratory of Hydraulics and Mountain River Engineering, College of Water Resource & Hydropower, Sichuan University, Chengdu 610065, China
| | - Torsten Schenkel
- Department of Engineering and Mathematics, Sheffield Hallam University, Sheffield S1 1WB, United Kingdom
| | - Jiguo Tang
- State Key Laboratory of Hydraulics and Mountain River Engineering, College of Water Resource & Hydropower, Sichuan University, Chengdu 610065, China.
| | - Hongtao Liu
- State Key Laboratory of Hydraulics and Mountain River Engineering, College of Water Resource & Hydropower, Sichuan University, Chengdu 610065, China
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15
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Li Z, Xu H, Armour CH, Guo Y, Xiong J, Xu X, Chen D. The Necessity to Seal the Re-Entry Tears of Aortic Dissection After TEVAR: A Hemodynamic Indicator. Front Bioeng Biotechnol 2022; 10:831903. [PMID: 35433660 PMCID: PMC9009393 DOI: 10.3389/fbioe.2022.831903] [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: 12/09/2021] [Accepted: 01/11/2022] [Indexed: 11/13/2022] Open
Abstract
Thoracic endovascular aortic repair (TEVAR) is a common treatment for Stanford type B aortic dissection (TBAD). However, re-entry tears might be found distal to the stented region which transports blood between the true and false lumens. Sealing the re-entry tears, especially for the thoracic tears, could further reduce blood perfusion to the false lumen; however, it might also bring risks by re-intervention or surgery. Wise determination of the necessity to seal the re-entry tears is needed. In this study, patient-specific models of TBAD were reconstructed, and the modified models were established by virtually excluding the thoracic re-entries. Computational hemodynamics was investigated, and the variation of the functional index and first balance position (FBP) of the luminal pressure difference, due to the sealing of the re-entries, was reported. The results showed that the direction of the net flow through the unstented thoracic re-entries varied among cases. Excluding the re-entries with the net flow toward the false lumen may induce the FBP moving distally and the relative particle residence time increasing in the false lumen. This study preliminarily demonstrated that the hemodynamic status of the re-entry tears might serve as an indicator to the necessity of sealing. By quantifying the through-tear flow exchange and shift of FBP, one can predict the hemodynamic benefit by sealing the thoracic re-entries and thus wisely determine the necessity of further interventional management.
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Affiliation(s)
- Zhenfeng Li
- School of Life Science, Beijing Institute of Technology, Beijing, China
- Wenzhou Safety (Emergency) Institute of Tianjin University, Zhejiang, China
| | - Huanming Xu
- School of Life Science, Beijing Institute of Technology, Beijing, China
| | - Chlöe Harriet Armour
- Department of Chemical Engineering, Imperial College London, London, United Kingdom
| | - Yuze Guo
- School of Biomedical Engineering, University of Sydney, Sydney, NSW, Australia
| | - Jiang Xiong
- Department of Vascular and Endovascular Surgery, Chinese PLA General Hospital, Beijing, China
- *Correspondence: Jiang Xiong, ; Xiaoyun Xu,
| | - Xiaoyun Xu
- Department of Chemical Engineering, Imperial College London, London, United Kingdom
- *Correspondence: Jiang Xiong, ; Xiaoyun Xu,
| | - Duanduan Chen
- School of Life Science, Beijing Institute of Technology, Beijing, China
- Wenzhou Safety (Emergency) Institute of Tianjin University, Zhejiang, China
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16
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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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17
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Armour CH, Guo B, Saitta S, Pirola S, Liu Y, Dong Z, Xu XY. Evaluation and verification of patient-specific modelling of type B aortic dissection. Comput Biol Med 2022; 140:105053. [PMID: 34847383 DOI: 10.1016/j.compbiomed.2021.105053] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 11/16/2021] [Accepted: 11/16/2021] [Indexed: 02/07/2023]
Abstract
Quantitative assessment of the complex hemodynamic environment in type B aortic dissection (TBAD) through computational fluid dynamics (CFD) simulations can provide detailed insights into the disease and its progression. As imaging and computational technologies have advanced, methodologies have been developed to increase the accuracy and physiological relevance of CFD simulations. This study presents a patient-specific workflow to simulate blood flow in TBAD, utilising the maximum amount of in vivo data available in the form of CT images, 4D-flow MRI and invasive Doppler-wire pressure measurements, to implement the recommended current best practice methodologies in terms of patient-specific geometry and boundary conditions. The study aimed to evaluate and verify this workflow through detailed qualitative and quantitative comparisons of the CFD and in vivo data. Based on data acquired from five TBAD patients, a range of essential model inputs was obtained, including inlet flow waveforms and 3-element Windkessel model parameters, which can be utilised in further studies where in vivo flow data is not available. Local and global analysis showed good consistency between CFD results and 4D-MRI data, with the maximum velocity in the primary entry tear differing by up to 0.3 m/s, and 80% of the analysed regions achieving moderate or strong correlations between the predicted and in vivo velocities. CFD predicted pressures were generally well matched to the Doppler-wire measurements, with some deviation in peak systolic values. Overall, this study presents a validated comprehensive workflow with extensive data for CFD simulation of TBAD.
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Affiliation(s)
- Chlöe H Armour
- Department of Chemical Engineering, Imperial College London, London, SW7 2AZ, UK
| | - Baolei Guo
- Department of Vascular Surgery, Zhongshan Hospital, Institute of Vascular Surgery, Fudan University, Shanghai, China
| | - Simone Saitta
- Department of Chemical Engineering, Imperial College London, London, SW7 2AZ, UK; Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milan, Italy
| | - Selene Pirola
- Department of Chemical Engineering, Imperial College London, London, SW7 2AZ, UK
| | - Yifan Liu
- Department of Vascular Surgery, Zhongshan Hospital, Institute of Vascular Surgery, Fudan University, Shanghai, China
| | - Zhihui Dong
- Department of Vascular Surgery, Zhongshan Hospital, Institute of Vascular Surgery, Fudan University, Shanghai, China.
| | - Xiao Yun Xu
- Department of Chemical Engineering, Imperial College London, London, SW7 2AZ, UK.
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18
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Abazari MA, Rafiei D, Soltani M, Alimohammadi M. The effect of beta-blockers on hemodynamic parameters in patient-specific blood flow simulations of type-B aortic dissection: a virtual study. Sci Rep 2021; 11:16058. [PMID: 34362955 PMCID: PMC8346572 DOI: 10.1038/s41598-021-95315-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Accepted: 07/20/2021] [Indexed: 12/23/2022] Open
Abstract
Aortic dissection (AD) is one of the fatal and complex conditions. Since there is a lack of a specific treatment guideline for type-B AD, a better understanding of patient-specific hemodynamics and therapy outcomes can potentially control the progression of the disease and aid in the clinical decision-making process. In this work, a patient-specific geometry of type-B AD is reconstructed from computed tomography images, and a numerical simulation using personalised computational fluid dynamics (CFD) with three-element Windkessel model boundary condition at each outlet is implemented. According to the physiological response of beta-blockers to the reduction of left ventricular contractions, three case studies with different heart rates are created. Several hemodynamic features, including time-averaged wall shear stress (TAWSS), highly oscillatory, low magnitude shear (HOLMES), and flow pattern are investigated and compared between each case. Results show that decreasing TAWSS, which is caused by the reduction of the velocity gradient, prevents vessel wall at entry tear from rupture. Additionally, with the increase in HOLMES value at distal false lumen, calcification and plaque formation in the moderate and regular-heart rate cases are successfully controlled. This work demonstrates how CFD methods with non-invasive hemodynamic metrics can be developed to predict the hemodynamic changes before medication or other invasive operations. These consequences can be a powerful framework for clinicians and surgical communities to improve their diagnostic and pre-procedural planning.
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Affiliation(s)
- Mohammad Amin Abazari
- Department of Mechanical Engineering, K. N. Toosi University of Technology, Tehran, Iran
| | - Deniz Rafiei
- Department of Mechanical Engineering, K. N. Toosi University of Technology, Tehran, Iran
| | - M Soltani
- Department of Mechanical Engineering, K. N. Toosi University of Technology, Tehran, Iran.
- Department of Electrical and Computer Engineering, Faculty of Engineering, School of Optometry and Vision Science, Faculty of Science, University of Waterloo, Waterloo, Canada.
- Advanced Bio Initiative Center, Multidisciplinary International Complex, K. N. Toosi University of Technology, Tehran, Iran.
- Centre for Biotechnology and Bioengineering (CBB), University of Waterloo, Waterloo, ON, Canada.
- Cancer Biology Research Center, Cancer Institute of Iran, Tehran University of Medical Sciences, Tehran, Iran.
| | - Mona Alimohammadi
- Department of Mechanical Engineering, K. N. Toosi University of Technology, Tehran, Iran.
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19
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Arthurs CJ, King AP. Active training of physics-informed neural networks to aggregate and interpolate parametric solutions to the Navier-Stokes equations. JOURNAL OF COMPUTATIONAL PHYSICS 2021; 438:None. [PMID: 34345054 PMCID: PMC8174474 DOI: 10.1016/j.jcp.2021.110364] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 03/13/2021] [Accepted: 04/11/2021] [Indexed: 06/13/2023]
Abstract
The goal of this work is to train a neural network which approximates solutions to the Navier-Stokes equations across a region of parameter space, in which the parameters define physical properties such as domain shape and boundary conditions. The contributions of this work are threefold:1.To demonstrate that neural networks can be efficient aggregators of whole families of parametric solutions to physical problems, trained using data created with traditional, trusted numerical methods such as finite elements. Advantages include extremely fast evaluation of pressure and velocity at any point in physical and parameter space (asymptotically, ∼3 μs/query), and data compression (the network requires 99% less storage space compared to its own training data).2.To demonstrate that the neural networks can accurately interpolate between finite element solutions in parameter space, allowing them to be instantly queried for pressure and velocity field solutions to problems for which traditional simulations have never been performed.3.To introduce an active learning algorithm, so that during training, a finite element solver can automatically be queried to obtain additional training data in locations where the neural network's predictions are in most need of improvement, thus autonomously acquiring and efficiently distributing training data throughout parameter space. In addition to the obvious utility of Item 2, above, we demonstrate an application of the network in rapid parameter sweeping, very precisely predicting the degree of narrowing in a tube which would result in a 50% increase in end-to-end pressure difference at a given flow rate. This capability could have applications in both medical diagnosis of arterial disease, and in computer-aided design.
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20
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Numerical Models Can Assist Choice of an Aortic Phantom for In Vitro Testing. Bioengineering (Basel) 2021; 8:bioengineering8080101. [PMID: 34436104 PMCID: PMC8389249 DOI: 10.3390/bioengineering8080101] [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: 05/19/2021] [Revised: 07/18/2021] [Accepted: 07/19/2021] [Indexed: 11/17/2022] Open
Abstract
(1) Background: The realization of appropriate aortic replicas for in vitro experiments requires a suitable choice of both the material and geometry. The matching between the grade of details of the geometry and the mechanical response of the materials is an open issue that deserves attention. (2) Methods: To explore this issue, we performed a series of Fluid–Structure Interaction simulations, which compared the dynamics of three aortic models. Specifically, we reproduced a patient-specific geometry with a wall of biological tissue or silicone, and a parametric geometry based on in vivo data made in silicone. The biological tissue and the silicone were modeled with a fiber-oriented anisotropic and isotropic hyperelastic model, respectively. (3) Results: Clearly, both the aorta’s geometry and its constitutive material contribute to the determination of the aortic arch deformation; specifically, the parametric aorta exhibits a strain field similar to the patient-specific model with biological tissue. On the contrary, the local geometry affects the flow velocity distribution quite a lot, although it plays a minor role in the helicity along the arch. (4) Conclusions: The use of a patient-specific prototype in silicone does not a priori ensure a satisfactory reproducibility of the real aorta dynamics. Furthermore, the present simulations suggest that the realization of a simplified replica with the same compliance of the real aorta is able to mimic the overall behavior of the vessel.
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21
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Li D, Zheng T, Liu Z, Li Y, Yuan D, Fan Y. Influence of Distal Re-entry Tears on False Lumen Thrombosis After Thoracic Endovascular Aortic Repair in Type B Aortic Dissection Patients: A Computational Fluid Dynamics Simulation. Cardiovasc Eng Technol 2021; 12:426-437. [PMID: 33768445 DOI: 10.1007/s13239-021-00532-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Accepted: 03/05/2021] [Indexed: 02/05/2023]
Abstract
PURPOSE Distal re-entry tears play a significant role in false lumen (FL) thrombosis, which will strongly affect the postoperative long-term survival of patients with type B aortic dissection (TBAD) after thoracic endovascular aortic repair (TEVAR). This study aimed to investigate the influence of a peculiar morphological parameter of the residual re-entry tears in TBAD patients after TEVAR on long-term FL thrombosis using the computational fluid dynamics. METHODS Ideal population-based three-dimensional models of post-operative TBAD were established. Numerical simulation was performed to investigate the hemodynamic differences caused by different tear features, including the tear count, the maximum distance between tears, and the tear area. RESULTS Although the low relative residence time (RRT) area did not change significantly when the tear distance was fixed, the area of oscillatory shear index (OSI) > 0.45 and endothelial cell activation potential (ECAP) > 1.5 decreased significantly with the tear count and area increased and a dramatic increase in blood flow into the FL was also observed. When tear count and total area were fixed, for each 10-mm increase in the maximum distance between tears, the area of low RRT in the FL increased significantly, while the average pressure difference increased by 10.85%. CONCLUSION The different morphology of the re-entry tears had different effects on the thrombosis-related hemodynamic parameters in FL following TEVAR. and the number of re-entry tears was most crucial to the potential thrombosis in the post-TEVAR FL of TBAD patients.
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Affiliation(s)
- Da Li
- Department of Applied Mechanics, Sichuan University, Chengdu, 610065, China
| | - Tinghui Zheng
- Department of Applied Mechanics, Sichuan University, Chengdu, 610065, China
| | - Zhan Liu
- Department of Applied Mechanics, Sichuan University, Chengdu, 610065, China
| | - Yan Li
- Department of Applied Mechanics, Sichuan University, Chengdu, 610065, China
| | - Ding Yuan
- Department Vascular Surgery of West China Hospital, Sichuan University, No. 37 Guo Xue Xiang, Chengdu, 610041, China.
| | - Yubo Fan
- Beijing Advanced Innovation Center of Biomedical Engineering, Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing, 100191, China.
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22
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A computational fluid study on hemodynamics in visceral arteries in a complicated type B aortic dissection after thoracic endovascular repair. MEDICINE IN NOVEL TECHNOLOGY AND DEVICES 2021. [DOI: 10.1016/j.medntd.2020.100054] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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23
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Arthurs CJ, Xiao N, Moireau P, Schaeffter T, Figueroa CA. A flexible framework for sequential estimation of model parameters in computational hemodynamics. ADVANCED MODELING AND SIMULATION IN ENGINEERING SCIENCES 2020; 7:48. [PMID: 33282681 PMCID: PMC7717067 DOI: 10.1186/s40323-020-00186-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2020] [Accepted: 11/06/2020] [Indexed: 06/02/2023]
Abstract
A major challenge in constructing three dimensional patient specific hemodynamic models is the calibration of model parameters to match patient data on flow, pressure, wall motion, etc. acquired in the clinic. Current workflows are manual and time-consuming. This work presents a flexible computational framework for model parameter estimation in cardiovascular flows that relies on the following fundamental contributions. (i) A Reduced-Order Unscented Kalman Filter (ROUKF) model for data assimilation for wall material and simple lumped parameter network (LPN) boundary condition model parameters. (ii) A constrained least squares augmentation (ROUKF-CLS) for more complex LPNs. (iii) A "Netlist" implementation, supporting easy filtering of parameters in such complex LPNs. The ROUKF algorithm is demonstrated using non-invasive patient-specific data on anatomy, flow and pressure from a healthy volunteer. The ROUKF-CLS algorithm is demonstrated using synthetic data on a coronary LPN. The methods described in this paper have been implemented as part of the CRIMSON hemodynamics software package.
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Affiliation(s)
| | - Nan Xiao
- Dept. of Biomedical Engineering, King’s College London, London, UK
| | - Philippe Moireau
- Inria, Inria Saclay-Ile de France, 91128 Palaiseau, France
- LMS, Ecole Polytechnique, CNRS, Institut Polytechnique de Paris, 91128 Palaiseau, France
| | - Tobias Schaeffter
- Physikalisch-Technische Bundesanstalt, Berlin, Germany
- Technical University Berlin, Berlin, Germany
| | - C. Alberto Figueroa
- Depts. of Surgery and Biomedical Engineering, University of Michigan, 2800 Plymouth Rd, Ann Arbor, MI 48109 USA
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24
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Numerical investigation of patient-specific thoracic aortic aneurysms and comparison with normal subject via computational fluid dynamics (CFD). Med Biol Eng Comput 2020; 59:71-84. [PMID: 33225424 DOI: 10.1007/s11517-020-02287-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2020] [Accepted: 11/05/2020] [Indexed: 10/22/2022]
Abstract
Vascular hemodynamics play an important role in cardiovascular diseases. This work aimed to investigate the effects of an increase in ascending aortic diameter (AAD) on hemodynamics throughout a cardiac cycle for real patients. In this study, two scans of thoracic aortic aneurysm (TAA) subject with different AADs (42.94 mm and 48.01 mm) and a scan of a normal subject (19.81 mm) were analyzed to assess the effects of hemodynamics on the progression of TAA with the same flow rate. Real-patient aortic geometries were scanned by computed tomography angiography (CTA), and steady and pulsatile flow conditions were used to simulate real patient aortic geometries. Aortic arches were obtained from routine clinical scans. Computational fluid dynamics (CFD) simulations were performed with in vivo boundary conditions, and 3D Navier-Stokes equations were solved by a UDF (user-defined function) code defining a real cardiac cycle of one patient using Fourier series (FS). Wall shear stress (WSS) and pressure distributions were presented from normal subject to TAA cases. The results show that during the peak systolic phase pressure load increased by 18.56% from normal subject to TAA case 1 and by 23.8% from normal subject to TAA case 2 in the aneurysm region. It is concluded that although overall WSS increased in aneurysm cases but was low in dilatation areas. As a result, abnormal changes in WSS and higher pressure load may lead to rupture and risk of further dilatation. CFD simulations were highly effective to guide clinical predictions and assess the progress of aneurysm regions in case of early surgical intervention. Graphical abstract.
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Mei Y, Xu H, Ma W, Li Z, Yang R, Yuan H, Peng Y, Wu M, Chen Z, Guo W, Gao T, Xiong J, Chen D. Retrograde branched extension limb assembling stent of pararenal abdominal aortic aneurysm: A longitudinal hemodynamic analysis for stent graft migration. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2020; 36:e3394. [PMID: 32790046 DOI: 10.1002/cnm.3394] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 03/31/2020] [Accepted: 08/02/2020] [Indexed: 06/11/2023]
Abstract
PURPOSE Pararenal abdominal aortic aneurysms (PRAAAs) are a life-threatening disease, and hemodynamic analysis may provide greater insight into the effectiveness and long-term outcomes of endovascular aneurysm repair (EVAR). However, the lack of patient-specific boundary conditions on the periphery compromises the accuracy. Windkessel (WK) boundary conditions coupled to hemodynamic follow-up models of a PRAAA patient, aims to provide insights into the link between hemodynamics and poor prognosis. METHOD One PRAAA patient underwent EVAR and reintervention after one branch of stent-graft (SG) had migrated. Totally five computational follow-up models were studied. Patient-specific flow data acquired via ultrasound were used to define the boundary conditions in the ascending aorta and the following three branches. Coupled zero-dimensional WK models representing the distal vasculature were used to define the outlet boundary conditions under the abdomen. RESULTS Flow divisions of the main SG branches were 40.7% and 24.7%, respectively. Time-averaged wall shear stress and oscillatory shear index (OSI) increased at the junction connected the SG branch and the stent leading to the right common iliac artery (RCIA) where the stent migrated. The OSI and relative residence time (RRT) value in superior mesenteric artery increased notably after the migration, the RRT continuously increased following the reintervention. CONCLUSION Unbalanced flow, resulting in locally high-speed flow, high WSS and OSI might significantly affect stent stability. Results suggest that diameters and interconnection design of stents in complex cases should take the flow division into consideration and computational simulations might be considered as a tool for intervention protocol design.
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Affiliation(s)
- Yuqian Mei
- School of Life Science, Beijing Institute of Technology, Beijing, China
| | - Huanming Xu
- School of Life Science, Beijing Institute of Technology, Beijing, China
| | - Wei Ma
- School of Life Science, Beijing Institute of Technology, Beijing, China
| | - Zhenfeng Li
- School of Life Science, Beijing Institute of Technology, Beijing, China
| | - Rui Yang
- Department of Vascular and Endovascular Surgery, Chinese PLA General Hospital, Beijing, China
| | - Hai Yuan
- Department of Vascular Surgery, Provincial Hospital Affiliated to Shandong University, Jinan, China
| | - Yan Peng
- Beijing CapitalBio Technology Corporation, Beijing, China
| | - Muyang Wu
- Department of Health Science Newark, University of Delaware, Newark, Delaware, USA
| | - Zhangtao Chen
- Department of Biomedical Engineering, Pennsylvania State University, State College, Pennsylvania, USA
| | - Wei Guo
- Department of Vascular and Endovascular Surgery, Chinese PLA General Hospital, Beijing, China
| | - Tianxin Gao
- School of Life Science, Beijing Institute of Technology, Beijing, China
| | - Jiang Xiong
- Department of Vascular and Endovascular Surgery, Chinese PLA General Hospital, Beijing, China
| | - Duanduan Chen
- School of Life Science, Beijing Institute of Technology, Beijing, China
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Surman TL, Abrahams JM, O'Rourke D, Reynolds KJ, Edwards J, Worthington MG, Beltrame J. The functional limits of the aneurysmal aortic root. A unique pressure testing apparatus. J Cardiothorac Surg 2020; 15:259. [PMID: 32943099 PMCID: PMC7500551 DOI: 10.1186/s13019-020-01288-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Accepted: 09/01/2020] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND The aortic root has unique embryological development and is a highly sophisticated and complex structure. In studies that report on the biomechanical characteristics of the thoracic aorta, distinction between the aortic root and ascending aorta regions is nonexistent. Our objective is to determine the maximal pressures at which dissection occurs or tissue failure occurs in the aortic root compared to that of the ascending aorta in the presence of aortic aneurysms. This may help guide preoperative monitoring, diagnosis and the decision for operative intervention for aortic root aneurysms in the normal and susceptible populations. METHODS We developed a simple aortic root and ascending aorta pressure testing unit in series. Ten fresh porcine hearts were obtained from the local abattoir (n = 5 aortic root and n = 5 ascending aorta for comparison). Using a saline filled needle and syringe, artificial fluid-filled aneurysms were created between the intima and medial layers of the aortic root. The aorta lumen was then progressively filled with saline solution. Pressure measurement was taken at time of loss of tissue integrity, obvious tissue dissection or aneurysm rupture, and the tissue structure was then visually examined. RESULTS In the aortic root, mean maximal pressure (mmHg) at tissue failure was 208 mmHg. Macroscopic examination revealed luminal tears around the coronary ostia in 2/5 specimens, and in all specimens, there was propagation of the dissection in the aortic root in a circumferential direction. In all ascending aorta specimens, the maximal aortic pressures exceeded 300 mmHg without tissue failure or dissection, and eventual apparatus failure. CONCLUSION Our results indicate that the aneurysmal aortic root tissues are at greater risk of rupture and dissection propagation at lower aortic pressure. With further analysis, this could guide clinical and surgical management.
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Affiliation(s)
- Timothy Luke Surman
- D'Arcy Sutherland Cardiothoracic Surgical Unit, Royal Adelaide Hospital, Adelaide, South Australia, Australia.
| | - John Matthew Abrahams
- D'Arcy Sutherland Cardiothoracic Surgical Unit, Royal Adelaide Hospital, Adelaide, South Australia, Australia
| | - Dermot O'Rourke
- Medical Device Research Institute, College of Science & Engineering, Flinders University, Adelaide, South Australia
| | - Karen Jane Reynolds
- Medical Device Research Institute, College of Science & Engineering, Flinders University, Adelaide, South Australia
| | - James Edwards
- D'Arcy Sutherland Cardiothoracic Surgical Unit, Royal Adelaide Hospital, Adelaide, South Australia, Australia
| | - Michael George Worthington
- D'Arcy Sutherland Cardiothoracic Surgical Unit, Royal Adelaide Hospital, Adelaide, South Australia, Australia
| | - John Beltrame
- Cardiology Department, Queen Elizabeth Hospital, Adelaide, South Australia
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Zadrazil I, Corzo C, Voulgaropoulos V, Markides CN, Xu XY. A combined experimental and computational study of the flow characteristics in a Type B aortic dissection: Effect of primary and secondary tear size. Chem Eng Res Des 2020. [DOI: 10.1016/j.cherd.2020.05.025] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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The effect of the entry and re-entry size in the aortic dissection: a two-way fluid-structure interaction simulation. Biomech Model Mechanobiol 2020; 19:2643-2656. [PMID: 32621161 DOI: 10.1007/s10237-020-01361-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 06/20/2020] [Indexed: 12/16/2022]
Abstract
Aortic dissection (AD) is one of the most catastrophic cardiovascular diseases. AD occurs when a layer inside the aorta is disrupted and gives rise to the formation of a true lumen and a false lumen. These lumens can be connected through tears in the intimal flap which are known as entries. Despite being known for about two centuries, the effects of many factors on the morbidity and mortality of this disease are still unknown. As the blood interaction with the aorta is crucial in the severity and the progression of the aortic dissection, a biomechanical approach is chosen to investigate the influence of different morphologies on the severity of this disease. Using the finite element method (FEM) and the fluid-structure interaction (FSI) approach, we have evaluated the blood flow characteristics along the diseased aorta, in conjunction with the deformation of the aortic wall. In this study, an idealized geometry of a dissected descending aorta (type B) with two entries has been studied. The values for the diameter of the entry tear were chosen to be 5 mm and 10 mm. Therefore, a total of four conditions were investigated. According to our results, the retrograde flow through the proximal tear is dependent on the size of the distal re-entry and vice versa. Our results revealed that when both entry and re-entry tears are 10 mm in diameter, the flow passes through the true and false lumens with smaller resistance, resulting in a smaller flutter of the intimal flap, and therefore more stable intimal flap. Major oscillation frequencies of 2.5 Hz and 7.4 Hz were observed for the oscillation of the intimal flap, and amplitudes of the waves with higher frequencies were negligible.
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Longitudinal computational fluid dynamics study of stenosis and aneurysmal degeneration of an aortorenal bypass. Biomech Model Mechanobiol 2020; 19:1965-1975. [PMID: 32200478 DOI: 10.1007/s10237-020-01320-9] [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: 10/16/2019] [Accepted: 03/12/2020] [Indexed: 02/05/2023]
Abstract
Saphenous vein graft (SVG) bypass placement is regarded as the optimal option for renal artery stenosis, which usually causes secondary hypertension and poor renal perfusion. Using computational fluid dynamics, this study aimed to investigate the underlying hemodynamic mechanism of the vein aneurysm and stenosis after aortorenal bypass surgery. Three-dimensional models were reconstructed based on computed tomographic angiography images of a 20-year-old female patient who suffered from uncontrollable hypertension using the image processing package Mimics (Materialise). The morphology and hemodynamic parameters in the healthy state, at initial presentation and at post-operative 9-month and 2-year follow-ups after surgery were analysed. The hemodynamic parameters became normal in the left and right renal arteries after bypass surgery. However, flow separation and stagnation occurred at the post-operative 9-month aorta-vein anastomosis, which caused asymmetrical flow and extremely high wall shear stress (WSS) and WSS gradients at the outflow vein tract, where the stenosis occurred 2 years later. In addition, the graft bending produced an asymmetrical flow pattern downstream. This research revealed that the abnormal hemodynamics, including flow separation and extremely high WSS values and gradients, caused by the retrograde flow of aortorenal bypass may be responsible for the SVG degeneration. In addition, flow asymmetry due to vessel bending is a potential risk factor for SVG aneurysm dilation.
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Xu H, Xiong J, Han X, Mei Y, Shi Y, Wang D, Zhang M, Chen D. Computed tomography-based hemodynamic index for aortic dissection. J Thorac Cardiovasc Surg 2020; 162:e165-e176. [PMID: 32217023 DOI: 10.1016/j.jtcvs.2020.02.034] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Revised: 02/03/2020] [Accepted: 02/04/2020] [Indexed: 10/25/2022]
Abstract
OBJECTIVE In this study we aimed to propose a new computed tomography-based hemodynamic indicator to quantify the functional significance of aortic dissection and predict post intervention luminal remodeling. METHODS Computational hemodynamics and 3D structural analyses were conducted in 51 patients with type B aortic dissection, at initial presentation and at approximately 1 month, 3 months, and 1 year post intervention. A functional index was proposed on the basis of luminal pressure difference. Statistical relationships between the proposed indicator and longitudinal luminal development were analyzed. RESULTS The computed luminal pressure difference (true lumen pressure minus false lumen pressure) varied overall from positive to negative along the aorta. The first balance position at which the pressure difference equals 0 was proposed as the functional indicator. A more distally located first balance position indicated better functional status. Implantation of stent graft distally shifted this balance position. Patients with the balance position shifted out of the dissected region (43%) presented the highest functional improvement after intervention; whereas those with the balance position shifted to the abdominal region (25%) showed unsatisfactory results. The magnitude of distal shifting of the first balance position at 3 months post intervention was statistically related to the subsequent true lumen expansion and false lumen reduction. CONCLUSIONS The first balance position of luminal pressure difference quantified the hemodynamic status of the dissected aorta. The magnitude of distal shifting of the balance position after intervention was associated with functional improvement and might be used predict longitudinal aortic remodeling.
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Affiliation(s)
- Huanming Xu
- Department of Biomedical Engineering, School of Life Science, Beijing Institute of Technology, Beijing, China
| | - Jiang Xiong
- Department of Vascular and Endovascular Surgery, Chinese PLA General Hospital, Beijing, China
| | - Xiaofeng Han
- Department of Diagnostic and Interventional Radiology, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
| | - Yuqian Mei
- Department of Biomedical Engineering, School of Life Science, Beijing Institute of Technology, Beijing, China
| | - Yue Shi
- Department of Engineering and Technology, Meiyin (Beijing) Medical Device Development Ltd, Beijing, China
| | - Dianpeng Wang
- Department of Probability and Statistics, School of Mathematics and Statistics, Beijing Institute of Technology, Beijing, China
| | - Mingchen Zhang
- Department of Mathematics, University of California Santa Barbara, Santa Barbara, Calif
| | - Duanduan Chen
- Department of Biomedical Engineering, School of Life Science, Beijing Institute of Technology, Beijing, China.
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Computational Fluid Dynamics Modeling of Hemodynamic Parameters in the Human Diseased Aorta: A Systematic Review. Ann Vasc Surg 2020; 63:336-381. [DOI: 10.1016/j.avsg.2019.04.032] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2018] [Revised: 03/09/2019] [Accepted: 04/18/2019] [Indexed: 02/07/2023]
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Xiong Z, Yang P, Li D, Qiu Y, Zheng T, Hu J. A computational fluid dynamics analysis of a patient with acute non-A-non-B aortic dissection after type I hybrid arch repair. Med Eng Phys 2020; 77:43-52. [PMID: 31948772 DOI: 10.1016/j.medengphy.2019.10.019] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 09/10/2019] [Accepted: 10/14/2019] [Indexed: 02/08/2023]
Abstract
The clinical presentation and natural courses in acute non-A-non-B aortic dissection (AD) are quite different from classical acute type A or type B AD, and the benefit of hybrid technique for this clinical scenario has not been validated. By using computational fluid dynamics (CFD) analysis, we aim to investigate a series of hemodynamic-related changes in aortic morphology in a patient who underwent type I hybrid arch repair (HAR). Computed tomographic angiographies (preoperative, one week, one month and one year after HAR) of a 52-year old male patient with arch-entry type acute non-A-non-B dissection were collected. Three-dimensional models were reconstructed by using an image processing package Mimics (materialize). Morphological and hemodynamic parameters of aorta and its branch vessels were analysed. Post-operatively, the false lumen index (FLI) gradually decreased from 2.02 to 0.38 and the curvature of the aortic arch was also reduced. However, the aortic arch lengthened and the diameter of the distal abdominal aorta expanded. In addition, the blood flow gradually became organised and the pressure in the true lumen (TL) increased over time and eventually approximated the pressure in the false lumen (FL). Moreover, the region of the abnormal wall shear stress (WSS) in the TL progressively decreased while the WSS in most areas of the FL remained below 4 dyne/cm2. The blood supply to most of the aortic branches returned to normal at the one-year follow-up. Type I HAR is an effective procedure for patients with acute non-A-non-B aortic dissection in terms of restoring normal blood flow in TL and facilitating positive remodeling of distal aorta. Long-term surveillance and follow-up is mandatory.
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Affiliation(s)
- Zhuxiang Xiong
- Department of Applied Mechanics, Sichuan University, Chengdu 610065, China
| | - Peng Yang
- Department of Cardiovascular Surgery, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Da Li
- Department of Applied Mechanics, Sichuan University, Chengdu 610065, China
| | - Yue Qiu
- Department of Applied Mechanics, Sichuan University, Chengdu 610065, China
| | - Tinghui Zheng
- Department of Applied Mechanics, Sichuan University, Chengdu 610065, China.
| | - Jia Hu
- Department of Cardiovascular Surgery, West China Hospital, Sichuan University, Chengdu 610041, China.
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Biomechanical implications of the fenestration structure after thoracic endovascular aortic repair. J Biomech 2020; 99:109478. [DOI: 10.1016/j.jbiomech.2019.109478] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2019] [Revised: 10/28/2019] [Accepted: 10/30/2019] [Indexed: 12/11/2022]
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Qiao Y, Mao L, Ding Y, Fan J, Zhu T, Luo K. Hemodynamic consequences of TEVAR with in situ double fenestrations of left carotid artery and left subclavian artery. Med Eng Phys 2019; 76:32-39. [PMID: 31882394 DOI: 10.1016/j.medengphy.2019.10.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Revised: 10/02/2019] [Accepted: 10/20/2019] [Indexed: 11/25/2022]
Abstract
The aortic major branches after thoracic endovascular aortic repair (TEVAR) could be preserved by in situ fenestration (ISF). This study aims to explore the hemodynamic consequences of ISF-TEVAR with double fenestrations. Two patients with aortic dissection and aneurysm, respectively, were treated by ISF-TEVAR and both the left carotid artery (LCA) and left subclavian artery (LSA) were reconstructed by fenestration technique. The blood was considered a non-Newtonian fluid and the Windkessel model was adopted at the aortic outlets. Simulations were performed in two postoperative models to analyze the effects of the double fenestration stents on the hemodynamics. The postoperative wall pressure of the LCA and LSA is relatively low and the pressure difference between the inner and outer walls of the protruding segment of the LSA stent is found. Acceleration occurs when blood flows around the fenestration stents and the shear-thinning rheological behavior is observed at the aortic arch. Moreover, regions susceptible to thrombosis are identified and the surface exposed to high relative residence time is located at the aortic arch after the LSA stent. The presence of the double fenestration stents has a profound impact on the postoperative hemodynamics, and the aortic arch and rebuilt branches should be closely watched during follow-up.
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Affiliation(s)
- Yonghui Qiao
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, China
| | - Le Mao
- Department of Vascular Surgery, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Ying Ding
- Department of Radiology, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Jianren Fan
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, China
| | - Ting Zhu
- Department of Vascular Surgery, Zhongshan Hospital, Fudan University, Shanghai, China.
| | - Kun Luo
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, China.
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Munshi B, Parker LP, Norman PE, Doyle BJ. The application of computational modeling for risk prediction in type B aortic dissection. J Vasc Surg 2019; 71:1789-1801.e3. [PMID: 31831314 DOI: 10.1016/j.jvs.2019.09.032] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Accepted: 09/04/2019] [Indexed: 02/06/2023]
Abstract
OBJECTIVE New tools are urgently needed to help with surgical decision-making in type B aortic dissection (TBAD) that is uncomplicated at the time of initial presentation. This narrative review aims to answer the clinical question, Can computational modeling be used to predict risk in acute and chronic Stanford TBAD? METHODS The review (PROSPERO 2018 CRD42018104472) focused on risk prediction in TBAD. A comprehensive search of the Ovid MEDLINE database, using terms related to computational modeling and aortic dissection, was conducted to find studies of any form published between 1998 and 2018. Cohort studies, case series, and case reports of adults (older than 18 years) with computed tomography or magnetic resonance imaging diagnosis of TBAD were included. Computational modeling was applied in all selected studies. RESULTS There were 37 studies about computational modeling of TBAD identified from the search, and the findings were synthesized into a narrative review. Computational modeling can produce numerically calculated values of stresses, pressures, and flow velocities that are difficult to measure in vivo. Hemodynamic parameters-high or low wall shear stress, high pressure gradient between lumens during the cardiac cycle, and high false lumen flow rate-have been linked to the pathogenesis of branch malperfusion and aneurysm formation by numerous studies. Considering the major outcomes of end-organ failure, aortic rupture, and stabilization and remodeling, hypotheses have been generated about inter-relationships of measurable parameters in computational models with observable anatomic and pathologic changes, resulting in specific clinical outcomes. CONCLUSIONS There is consistency in study findings about computational modeling in TBAD, although a limited number of patients have been analyzed using various techniques. The mechanistic patterns of association found in this narrative review should be investigated in larger cohort prospective studies to further refine our understanding. It highlights the importance of patient-specific computational hemodynamic parameters in clinical decision-making algorithms. The current challenge is to develop and to test a risk assessment method that can be used by clinicians for TBAD.
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Affiliation(s)
- Bijit Munshi
- Vascular Engineering Laboratory, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, Australia; Centre for Medical Research, The University of Western Australia, Perth, Australia; Medical School, The University of Western Australia, Perth, Australia; Department of Vascular Surgery, Fiona Stanley Hospital, Perth, Australia
| | - Louis P Parker
- Vascular Engineering Laboratory, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, Australia; Centre for Medical Research, The University of Western Australia, Perth, Australia; School of Engineering, The University of Western Australia, Perth, Australia
| | - Paul E Norman
- Vascular Engineering Laboratory, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, Australia; Centre for Medical Research, The University of Western Australia, Perth, Australia; Medical School, The University of Western Australia, Perth, Australia; Department of Vascular Surgery, Fiona Stanley Hospital, Perth, Australia
| | - Barry J Doyle
- Vascular Engineering Laboratory, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, Australia; Centre for Medical Research, The University of Western Australia, Perth, Australia; School of Engineering, The University of Western Australia, Perth, Australia.
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Pirola S, Guo B, Menichini C, Saitta S, Fu W, Dong Z, Xu XY. 4-D Flow MRI-Based Computational Analysis of Blood Flow in Patient-Specific Aortic Dissection. IEEE Trans Biomed Eng 2019; 66:3411-3419. [DOI: 10.1109/tbme.2019.2904885] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Patient-specific and real-time model of numerical simulation of the hemodynamics of type B aortic dissections. Med Hypotheses 2019; 135:109477. [PMID: 31756588 DOI: 10.1016/j.mehy.2019.109477] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Revised: 11/05/2019] [Accepted: 11/08/2019] [Indexed: 01/16/2023]
Abstract
INTRODUCTION Regular monitoring of uncomplicated type B aortic dissection is essential because 25-30% will progress to aneurysmal form. The predictive factors of this evolution are not clearly defined, but they seem to be correlated with hemodynamic data. HYPOTHESIS Our goal is to create a patient-specific and real-time model of numerical simulation of the hemodynamics of uncomplicated type B aortic dissections in order to predict the evolution of these pathologies for earlier treatment. METHOD This model consists in a coupling 0D (hydraulic-electric analogy) - 3D (CT angiography segmentation) of the aortic arch with optimization by comparison to the 2D Phase Contrast MRI data and using Reduced Order Models to drastically reduce computing times. We tested our model on a healthy and a dissected patient. Then we realized different systolic blood pressure scenarios for each case, which we compared. RESULTS In the dissected patient, the blood pressure at the false lumen wall was less important than the true lumen. Furthermore, the aortic wall shear stress and the velocity fields in aorta increase at the entry and re-entry tears between the two lumens. The simulation of different blood pressures scenarios shows a decrease in all these three parameters related to the decrease of the systolic blood pressure. CONCLUSION Our model provides reliable patient-specific and real-time 3D rendering. It has also allowed us to realize different flow variation scenarios to simulate different clinical conditions and to compare them. However, the model still needs improvement in view of a daily clinical application.
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Patient-specific haemodynamic simulations of complex aortic dissections informed by commonly available clinical datasets. Med Eng Phys 2019; 71:45-55. [DOI: 10.1016/j.medengphy.2019.06.012] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 05/22/2019] [Accepted: 06/09/2019] [Indexed: 12/26/2022]
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Qiu Y, Wang Y, Fan Y, Peng L, Liu R, Zhao J, Yuan D, Zheng T. Role of intraluminal thrombus in abdominal aortic aneurysm ruptures: A hemodynamic point of view. Med Phys 2019; 46:4263-4275. [PMID: 31206182 DOI: 10.1002/mp.13658] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Revised: 05/27/2019] [Accepted: 06/05/2019] [Indexed: 02/05/2023] Open
Abstract
PURPOSE Intraluminal thrombus (ILTs) are found in most abdominal aortic aneurysms (AAAs) of clinically relevant size; however, the role of ILTs in AAA ruptures remains unclear. This study investigated the role of the presence and thickness of ILTs in AAA ruptures by analyzing the hemodynamic environment in ruptured AAAs (RAAAs). METHODS Three-dimensional reconstructions from computed tomography scans were performed, and 13 RAAA cases were categorized into a no-ILT group, a thin-layered ILT group (thickness < 3 mm), and a thick-layered ILT group. The hemodynamic features of the RAAAs were assessed using computational fluid dynamics simulation. RESULTS The thin- and thick-layered ILT groups showed significant differences in aneurysm diameters (P < 0.05). The three types of AAAs ruptured at different flow regions, with different hemodynamic features: (a) the no-ILT AAAs ruptured at regions of flow recirculation where velocity and wall shear stresses (WSSs) were close to zero; (b) the thin-layered ILT AAAs ruptured at sites at which the dominant flow impinged the wall; and (c) the thick-layered ILT AAAs ruptured at the border of the dominant flow channel and recirculation zone where the flow velocity and pressure changed dramatically. CONCLUSIONS Hemodynamic characteristics influence the rupture mechanisms of particular AAAs differently on the basis of the presence and thickness of ILTs. Recirculation flows and low WSSs may have negative effects by inducing local rupture or positive effects by promoting the formation of thin-layered ILTs. However, eccentrically located thick-layered ILTs may increase the rupture risk of small AAAs because of their location in the sac lumen, which results in chaotic flow patterns and rapid increases in flow resistance.
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Affiliation(s)
- Yue Qiu
- Department of Applied Mechanics, Sichuan University, Chengdu, 610065, China
| | - Yi Wang
- Department of Computer Science, Sichuan University of Science and Engineering, Zigong, Sichuan, 643000, China
| | - Yubo Fan
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing, 100191, P. R. China
| | - Liqing Peng
- The Department of Radiology, West China Hospital, Sichuan University, Chengdu, China
| | - Rong Liu
- Institute of Textiles and Clothing, The Hong Kong Polytechnic University, Hong Kong, China
| | - Jichun Zhao
- Department Vascular Surgery of West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Ding Yuan
- Department Vascular Surgery of West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Tinghui Zheng
- Department of Applied Mechanics, Sichuan University, Chengdu, 610065, China
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40
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Athanasiou LS, Nezami FR, Edelman ER. Hemodynamic consequences of a multilayer flow modulator in aortic dissection. Med Biol Eng Comput 2019; 57:1861-1874. [PMID: 31209712 DOI: 10.1007/s11517-019-01997-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Accepted: 05/22/2019] [Indexed: 10/26/2022]
Abstract
Aortic dissections are challenging for it remains perplexing to determine when surgical, endovascular, or medical therapies are optimal. We studied the effect of the multilayer flow modulator (MFM) device in patients with different forms of type-B aortic dissections. CT scans were performed pre-, immediately post-MFM implantation, and multiple times within a 24-month follow-up. Three-dimensional reconstructions were created from these scans and the multilayer or single-layer mesh device placed virtually into the true lumen. We observed that MFM device can sufficiently restore flow perfusion, reduce the false lumen, eliminate local flow recirculation, and reduce wall shear stress distribution globally. Single-layer devices can reduce false lumen dimensions; however, they generate local disturbance and recirculation zones in selected areas at specific time points. Moreover, in polar extremes of dissection, the MFM device restored flow to vital organs perfusing vessels independent of effects on luminal patency. Management of aortic dissections should focus on modulation of blood flow, suppression of local recirculation, and restoration of vital organ perfusion rather than primarily restoring vascular lumen morphology. While the latter restores the geometry of the true lumen, only the former restores homeostasis. Graphical abstract.
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Affiliation(s)
- Lambros S Athanasiou
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, USA. .,Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
| | - Farhad Rikhtegar Nezami
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Elazer R Edelman
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, USA.,Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
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41
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Auricchio F, Conti M, Romarowski RM, de Beaufort HW, Grassi V, Trimarchi S. Computational tools for thoracic endovascular aortic repair planning. ITALIAN JOURNAL OF VASCULAR AND ENDOVASCULAR SURGERY 2019. [DOI: 10.23736/s1824-4777.18.01386-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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42
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Huang H, Shu Z, Song B, Ji L, Zhu N. Modeling left ventricular dynamics using a switched system approach based on a modified atrioventricular piston unit. Med Eng Phys 2018; 63:42-49. [PMID: 30554979 DOI: 10.1016/j.medengphy.2018.12.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Revised: 11/26/2018] [Accepted: 12/04/2018] [Indexed: 11/29/2022]
Abstract
The contribution of the longitudinal atrioventricular plane displacement to ventricular pumping has drawn more and more attentions. In this paper, differential equations of the left ventricle (LV) are derived via the atrioventricular piston concept. The contribution of left ventricular radial function to blood flow was converted to an equivalent coefficient. A systemic circulatory model incorporating the modified atrioventricular piston unit was developed on a switched system form by adding some state-dependent switching planes. Simulation results prove that the end-systolic pressure volume relationship of the model with a changing systemic arterial resistance is approximately linear and insensitive to perturbations in afterload. Then the LV model was validated using a data fitting method. A pressure-volume loop from a patient undergoing routine diagnostic cardiac catheterization with LV angiography was used as measurements. Model parameters and the trapezoidal profile of contraction forces were adjusted by a trial method. The root mean squared error between the measured and estimated LV pressure is 2.99 mmHg. The LV compliance is 0.34 ml/mmHg. The ratio between left ventricular and left atrial cross-section is 1.8. Therefore, parameter values used in the modified LV model match physiological data. The model can reproduce the realistic pressure-flow relationship in the LV chamber.
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Affiliation(s)
- Huan Huang
- School of Electrical Engineering and Automation, Jiangsu Normal University, Xuzhou, Jiangsu, China
| | - Zhan Shu
- School of Electrical Engineering and Automation, Jiangsu Normal University, Xuzhou, Jiangsu, China; Electro-Mechanical Group, Faculty of Engineering and the Environment, University of Southampton, Southampton SO17 1BJ, UK.
| | - Bo Song
- School of Electrical Engineering and Automation, Jiangsu Normal University, Xuzhou, Jiangsu, China
| | - Liya Ji
- Department of Cardiology, Xuzhou Central Hospital, Xuzhou, Jiangsu, China
| | - Nan Zhu
- School of Electrical Engineering and Automation, Jiangsu Normal University, Xuzhou, Jiangsu, China
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43
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Rikhtegar Nezami F, Athanasiou LS, Amrute JM, Edelman ER. Multilayer flow modulator enhances vital organ perfusion in patients with type B aortic dissection. Am J Physiol Heart Circ Physiol 2018; 315:H1182-H1193. [PMID: 30095992 DOI: 10.1152/ajpheart.00199.2018] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Management of aortic dissections (AD) is still challenging, with no universally approved guideline among possible surgical, endovascular, or medical therapies. Approximately 25% of patients with AD suffer postintervention malperfusion syndrome or hemodynamic instability, with the risk of sudden death if left untreated. Part of the issue is that vascular implants may themselves induce flow disturbances that critically impact vital organs. A multilayer mesh construct might obviate the induced flow disturbances, and it is this concept we investigated. We used preintervention and post-multilayer flow modulator implantation (PM) geometries from clinical cases of type B AD. In-house semiautomatic segmentation routines were applied to computed tomography images to reconstruct the lumen. The device was numerically reconstructed and adapted to the PM geometry concentrically fit to the true lumen centerline. We also numerically designed a pseudohealthy case, where the geometry of the aorta was extracted interpolating geometric features of preintervention, postimplantation, and published representative healthy volunteers. Computational fluid dynamics methods were used to study the time-dependent flow patterns, shear stress metrics, and perfusion to vital organs. A three-element Windkessel lumped parameter module was coupled to a finite-volume solver to assign dynamic outlet boundary conditions. Multilayer flow modulator not only significantly reduced false lumen blood flow, eliminated local flow disturbances, and globally regulated wall shear stress distribution but also maintained physiological perfusion to peripheral vital organs. We propose further investigation to focus the management of AD on both modulation of blood flow and restoration of physiologic end-organ perfusion rather than mere restoration of vascular lamina morphology. NEW & NOTEWORTHY The majority of aortic dissection modeling efforts have focused on the maintenance of physiological flow using minimally invasive placed grafts. The multilayer flow modulator is a complex mesh construct of wires, designed to eliminate flow disruptions in the lumen, regulate the physiological wall stresses, and enhance endothelial function and offering the promise of improved perfusion of vital organs. This has never been fully proved or modeled, and these issues we confirmed using a dynamic framework of time-varying arterial waveforms.
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Affiliation(s)
- Farhad Rikhtegar Nezami
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology , Cambridge, Massachusetts
| | - Lambros S Athanasiou
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology , Cambridge, Massachusetts.,Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School , Boston, Massachusetts
| | - Junedh M Amrute
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology , Cambridge, Massachusetts.,Division of Biology and Biological Engineering, California Institute of Technology , Pasadena, California
| | - Elazer R Edelman
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology , Cambridge, Massachusetts.,Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School , Boston, Massachusetts
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44
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Bonfanti M, Balabani S, Greenwood JP, Puppala S, Homer-Vanniasinkam S, Díaz-Zuccarini V. Computational tools for clinical support: a multi-scale compliant model for haemodynamic simulations in an aortic dissection based on multi-modal imaging data. J R Soc Interface 2018; 14:rsif.2017.0632. [PMID: 29118115 PMCID: PMC5721167 DOI: 10.1098/rsif.2017.0632] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 10/13/2017] [Indexed: 11/12/2022] Open
Abstract
Aortic dissection (AD) is a vascular condition with high morbidity and mortality rates. Computational fluid dynamics (CFD) can provide insight into the progression of AD and aid clinical decisions; however, oversimplified modelling assumptions and high computational cost compromise the accuracy of the information and impede clinical translation. To overcome these limitations, a patient-specific CFD multi-scale approach coupled to Windkessel boundary conditions and accounting for wall compliance was developed and used to study a patient with AD. A new moving boundary algorithm was implemented to capture wall displacement and a rich in vivo clinical dataset was used to tune model parameters and for validation. Comparisons between in silico and in vivo data showed that this approach successfully captures flow and pressure waves for the patient-specific AD and is able to predict the pressure in the false lumen (FL), a critical variable for the clinical management of the condition. Results showed regions of low and oscillatory wall shear stress which, together with higher diastolic pressures predicted in the FL, may indicate risk of expansion. This study, at the interface of engineering and medicine, demonstrates a relatively simple and computationally efficient approach to account for arterial deformation and wave propagation phenomena in a three-dimensional model of AD, representing a step forward in the use of CFD as a potential tool for AD management and clinical support.
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Affiliation(s)
- Mirko Bonfanti
- Department of Mechanical Engineering, University College London, Torrington Place, London WC1E 7JE, UK
| | - Stavroula Balabani
- Department of Mechanical Engineering, University College London, Torrington Place, London WC1E 7JE, UK
| | - John P Greenwood
- Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds LS2 9JT, UK.,Leeds Teaching Hospitals NHS Trust, Leeds LS1 3EX, UK
| | - Sapna Puppala
- Leeds Teaching Hospitals NHS Trust, Leeds LS1 3EX, UK
| | - Shervanthi Homer-Vanniasinkam
- Department of Mechanical Engineering, University College London, Torrington Place, London WC1E 7JE, UK.,Leeds Teaching Hospitals NHS Trust, Leeds LS1 3EX, UK.,University of Warwick Medical School & University Hospitals Coventry and Warwickshire NHS Trust, Coventry CV2 2DX, UK
| | - Vanessa Díaz-Zuccarini
- Department of Mechanical Engineering, University College London, Torrington Place, London WC1E 7JE, UK
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45
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van Bakel TM, Romarowski RM, Morganti S, van Herwaarden JA, Moll FL, de Beaufort HW, Marrocco-Trischitta MM, Secchi F, Conti M, Auricchio F, Trimarchi S. Blood Flow after Endovascular Repair in the Aortic Arch: A Computational Analysis. AORTA (STAMFORD, CONN.) 2018; 6:81-87. [PMID: 30795032 PMCID: PMC6386644 DOI: 10.1055/s-0039-1683771] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Accepted: 11/05/2018] [Indexed: 01/26/2023]
Abstract
BACKGROUND The benefits of thoracic endovascular aortic repair (TEVAR) have encouraged stent graft deployment more proximally in the aortic arch. This study quantifies the hemodynamic impact of TEVAR in proximal landing zone 2 on the thoracic aorta and the proximal supra-aortic branches. METHODS Patients treated with TEVAR in proximal landing zone 2 having available preoperative and 30-day postoperative computer tomography angiography and phase-contrast magnetic resonance imaging data were retrospectively selected. Blood flow was studied using patient-specific computational fluid dynamics simulations. RESULTS Four patients were included. Following TEVAR in proximal landing zone 2, the mean flow in the left common carotid artery (LCCA) increased almost threefold, from 0.21 (0.12-0.41) L/min to 0.61 (0.24-1.08) L/min (+294%). The surface area of the LCCA had not yet increased commensurately and therefore maximum flow velocity in the LCCA increased from 44.9 (27.0-89.3) cm/s to 72.6 (40.8-135.0) cm/s (+62%). One of the patients presented with Type Ib endoleak at 1-year follow-up. The displacement force in this patient measured 32.1 N and was directed dorsocranial, perpendicular to the distal sealing zone. There was a linear correlation between the surface area of the stent graft and the resulting displacement force (p = 0.04). CONCLUSION TEVAR in proximal landing zone 2 alters blood flow in the supra-aortic branches, resulting in increased flow with high flow velocities in the LCCA. High displacement forces were calculated and related to stent graft migration and Type I endoleak during 1-year follow-up.
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Affiliation(s)
- Theodorus M. van Bakel
- Thoracic Aortic Research Center, IRCCS—Policlinico San Donato, University of Milan, Milan, Italy
- Department of Vascular Surgery, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Rodrigo M. Romarowski
- Thoracic Aortic Research Center, IRCCS—Policlinico San Donato, University of Milan, Milan, Italy
- Department of Civil Engineering and Architecture, University of Pavia, Pavia, Italy
| | - Simone Morganti
- Department of Civil Engineering and Architecture, University of Pavia, Pavia, Italy
| | | | - Frans L. Moll
- Department of Vascular Surgery, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Hector W. de Beaufort
- Thoracic Aortic Research Center, IRCCS—Policlinico San Donato, University of Milan, Milan, Italy
- Department of Vascular Surgery, University Medical Center Utrecht, Utrecht, The Netherlands
| | | | - Francesco Secchi
- Department of Radiology, IRCCS—Policlinico San Donato, San Donato Milanese, Italy
| | - Michele Conti
- Department of Civil Engineering and Architecture, University of Pavia, Pavia, Italy
| | - Ferdinando Auricchio
- Department of Civil Engineering and Architecture, University of Pavia, Pavia, Italy
| | - Santi Trimarchi
- Thoracic Aortic Research Center, IRCCS—Policlinico San Donato, University of Milan, Milan, Italy
- Department of Biomedical Sciences for Health, University of Milan, Milan, Italy
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46
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Bonfanti M, Balabani S, Alimohammadi M, Agu O, Homer-Vanniasinkam S, Díaz-Zuccarini V. A simplified method to account for wall motion in patient-specific blood flow simulations of aortic dissection: Comparison with fluid-structure interaction. Med Eng Phys 2018; 58:S1350-4533(18)30074-2. [PMID: 29759947 DOI: 10.1016/j.medengphy.2018.04.014] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Revised: 04/16/2018] [Accepted: 04/30/2018] [Indexed: 10/16/2022]
Abstract
Aortic dissection (AD) is a complex and highly patient-specific vascular condition difficult to treat. Computational fluid dynamics (CFD) can aid the medical management of this pathology, yet its modelling and simulation are challenging. One aspect usually disregarded when modelling AD is the motion of the vessel wall, which has been shown to significantly impact simulation results. Fluid-structure interaction (FSI) methods are difficult to implement and are subject to assumptions regarding the mechanical properties of the vessel wall, which cannot be retrieved non-invasively. This paper presents a simplified 'moving-boundary method' (MBM) to account for the motion of the vessel wall in type-B AD CFD simulations, which can be tuned with non-invasive clinical images (e.g. 2D cine-MRI). The method is firstly validated against the 1D solution of flow through an elastic straight tube; it is then applied to a type-B AD case study and the results are compared to a state-of-the-art, full FSI simulation. Results show that the proposed method can capture the main effects due to the wall motion on the flow field: the average relative difference between flow and pressure waves obtained with the FSI and MBM simulations was less than 1.8% and 1.3%, respectively and the wall shear stress indices were found to have a similar distribution. Moreover, compared to FSI, MBM has the advantage to be less computationally expensive (requiring half of the time of an FSI simulation) and easier to implement, which are important requirements for clinical translation.
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Affiliation(s)
- Mirko Bonfanti
- Department of Mechanical Engineering, University College London, WC1E 7JE, UK.
| | - Stavroula Balabani
- Department of Mechanical Engineering, University College London, WC1E 7JE, UK
| | - Mona Alimohammadi
- Department of Mechanical Engineering, University College London, WC1E 7JE, UK
| | | | - Shervanthi Homer-Vanniasinkam
- Department of Mechanical Engineering, University College London, WC1E 7JE, UK; Leeds Teaching Hospitals NHS Trust, LS1 3EX, UK; University of Warwick Medical School & University Hospitals Coventry and Warwickshire NHS Trust, CV4 7AL, UK
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47
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Razavi SE, Farhangmehr V, Zendeali N. Numerical investigation of the blood flow through the middle cerebral artery. ACTA ACUST UNITED AC 2018; 8:195-200. [PMID: 30211079 PMCID: PMC6128971 DOI: 10.15171/bi.2018.22] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Revised: 04/29/2018] [Accepted: 05/01/2018] [Indexed: 11/09/2022]
Abstract
Introduction: The middle cerebral artery (MCA) is one of the three major paired arteries that supply the blood to the cerebrum. In the present study, the three-dimensional (3D) blood flow in the left MCA was numerically simulated by using the medical imaging. Methods: The arterial geometry was obtained by applying the CT angiography of the MCA of a 75-year-old man. The blood flow was assumed to be laminar and unsteady. Numerical simulations were done by commercial software package COMSOL Multiphysics 5.2. In this software, the Galerkin's finite element method was applied to solve the governing equations. Results: It was found that the results obtained for the Newtonian and non-Newtonian models of blood do not differ from each other significantly. Thus, the Newtonian model for blood flow in the MCA is acceptable. Also, the most susceptible region of the MCA for Atherosclerosis was detected. Conclusion: It can be concluded that the application of the Newtonian model for the blood flowing in the MCA is acceptable. Also, atherosclerosis has the potential to occur at the middle of a branch of the MCA which has the highest geometrical curvature.
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Affiliation(s)
- Seyed Esmail Razavi
- Department of Mechanical Engineering, Faculty of Mechanical Engineering, University of Tabriz, Tabriz, Iran
| | - Vahid Farhangmehr
- Department of Mechanical Engineering, University of Bonab, Bonab, Iran
| | - Nafiseh Zendeali
- Department of Mechanical Engineering, Faculty of Mechanical Engineering, University of Tabriz, Tabriz, Iran
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48
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Xu H, Piccinelli M, Leshnower BG, Lefieux A, Taylor WR, Veneziani A. Coupled Morphological-Hemodynamic Computational Analysis of Type B Aortic Dissection: A Longitudinal Study. Ann Biomed Eng 2018; 46:927-939. [PMID: 29594688 DOI: 10.1007/s10439-018-2012-z] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Accepted: 03/21/2018] [Indexed: 10/17/2022]
Abstract
Progressive false lumen aneurysmal degeneration in type B aortic dissection (TBAD) is a complex process with a multi-factorial etiology. Patient-specific computational fluid dynamics (CFD) simulations provide spatial and temporal hemodynamic quantities that facilitate understanding this disease progression. A longitudinal study was performed for a TBAD patient, who was diagnosed with the uncomplicated TBAD in 2006 and treated with optimal medical therapy but received surgery in 2010 due to late complication. Geometries of the aorta in 2006 and 2010 were reconstructed. With registration algorithms, we accurately quantified the evolution of the false lumen, while with CFD simulations we computed several hemodynamic indexes, including the wall shear stress (WSS), and the relative residence time (RRT). The numerical fluid model included large eddy simulation (LES) modeling for efficiently capturing the flow disturbances induced by the entry tears. In the absence of complete patient-specific data, the boundary conditions were based on a specific calibration method. Correlations between hemodynamics and the evolution field in time obtained by registration of the false lumen are discussed. Further testing of this methodology on a large cohort of patients may enable the use of CFD to predict whether patients, with originally uncomplicated TBAD, develop late complications.
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Affiliation(s)
- Huijuan Xu
- The George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, USA. .,Department of Mathematics and Computer Science, Emory University, Atlanta, USA.
| | - Marina Piccinelli
- Department of Radiology and Imaging Sciences, Emory University, Atlanta, USA
| | | | - Adrien Lefieux
- Department of Mathematics and Computer Science, Emory University, Atlanta, USA.,Department of Cardiology, Emory University, Atlanta, USA
| | - W Robert Taylor
- Department of Cardiology, Emory University, Atlanta, USA.,Atlanta VA Medical Center, Atlanta, USA
| | - Alessandro Veneziani
- Department of Mathematics and Computer Science, Emory University, Atlanta, USA.,School of Advanced Studies IUSS, Pavia, Italy
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49
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Menichini C, Cheng Z, Gibbs RG, Xu XY. A computational model for false lumen thrombosis in type B aortic dissection following thoracic endovascular repair. J Biomech 2018; 66:36-43. [DOI: 10.1016/j.jbiomech.2017.10.029] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Revised: 09/28/2017] [Accepted: 10/27/2017] [Indexed: 10/18/2022]
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50
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Roustaei M, Nikmaneshi MR, Firoozabadi B. Simulation of Low Density Lipoprotein (LDL) permeation into multilayer coronary arterial wall: Interactive effects of wall shear stress and fluid-structure interaction in hypertension. J Biomech 2018; 67:114-122. [DOI: 10.1016/j.jbiomech.2017.11.029] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Revised: 11/19/2017] [Accepted: 11/26/2017] [Indexed: 10/18/2022]
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