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Keramati H, Birgersson E, Kim S, Leo HL. A Monte Carlo Sensitivity Analysis for a Dimensionally Reduced-Order Model of the Aortic Dissection. Cardiovasc Eng Technol 2024; 15:333-345. [PMID: 38381368 DOI: 10.1007/s13239-024-00718-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Accepted: 01/11/2024] [Indexed: 02/22/2024]
Abstract
PURPOSE Aortic dissection is associated with a high mortality rate. Although computational approaches have shed light on many aspects of the disease, a sensitivity analysis is required to determine the significance of different factors. Because of its complex geometry and high computational expense, the three-dimensional (3D) fluid-structure interaction (FSI) simulation is not a suitable approach for sensitivity analysis. METHODS We performed a Monte Carlo simulation (MCS) to investigate the sensitivity of hemodynamic quantities to the lumped parameters of our zero-dimensional (0D) model with numerically calculated lumped parameters. We performed local and global analyses on the effect of the model parameters on important hemodynamic quantities. RESULTS The MCS showed that a larger lumped resistance value for the false lumen and the tears result in a higher retrograde flow rate in the false lumen (the coefficient of variation,c v , i = 0.0183 , the sensitivityS X i σ = 0.54 , Spearman's coefficient,ρ s = 0.464 ). For the intraluminal pressure, our results show a significant role in the resistance and inertance of the true lumen (the coefficient of variation,c v , i = 0.0640 , the sensitivityS X i σ = 0.85 , and Spearman's coefficient,ρ s = 0.855 for the inertance of the true lumen). CONCLUSION This study highlights the necessity of comparing the results of the local and global sensitivity analyses to understand the significance of multiple lumped parameters. Because of the efficiency of the method, our approach is potentially useful to investigate and analyze medical planning.
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Affiliation(s)
- Hamed Keramati
- Integrative Sciences and Engineering Programme (ISEP), National University of Singapore, Singapore, Singapore
- Department of Biomedical Engineering, National University of Singapore, Singapore, 117576, Singapore
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, UK
| | - Erik Birgersson
- Department of Mechanical Engineering, National University of Singapore, Singapore, 117575, Singapore
| | - Sangho Kim
- Integrative Sciences and Engineering Programme (ISEP), National University of Singapore, Singapore, Singapore
- Department of Biomedical Engineering, National University of Singapore, Singapore, 117576, Singapore
| | - Hwa Liang Leo
- Integrative Sciences and Engineering Programme (ISEP), National University of Singapore, Singapore, Singapore.
- Department of Biomedical Engineering, National University of Singapore, Singapore, 117576, Singapore.
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Guo B, Akhtar R, Liu H, Yan C, Guo D, Patterson B, Fu W. Staged surgically created type B aortic dissection model with endovascular reintervention for different morphological features. INTERDISCIPLINARY CARDIOVASCULAR AND THORACIC SURGERY 2023; 37:ivad133. [PMID: 37561091 PMCID: PMC10656095 DOI: 10.1093/icvts/ivad133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 05/28/2023] [Accepted: 08/09/2023] [Indexed: 08/11/2023]
Abstract
OBJECTIVES Understanding morphology and how this relates to treatment strategy is critical for achieving remodelling in aortic dissection. A controllable and reproducible large animal model is required for investigating new therapeutic devices and interventions. METHODS Our experimental protocol involved the development of surgically created type B aortic dissection (TBAD) and endovascular reintervention-induced TBAD porcine models. The sample was randomly divided into 2 groups: 1 underwent a secondary tear creation (STC) procedure and the other underwent a false lumen extension (FLE) procedure. Anatomical features were observed at 1 and 3 months, and 2 animals in each group were euthanized at 3 months after the procedures. The aorta and main branches were harvested en bloc, cross-sectioned and prepared for histological examination. RESULTS All surgically created TBAD models were successfully generated, and no unintended complications occurred. The endovascular reintervention-induced TBAD model was successfully created in 11 of 12 animals, with 6 in the STC group and 5 in the FLE group. In the STC group, the intraoperative mean diameter of the new secondary tear was 7.23 mm, and a slight increase was observed at first 30 days (P = 0.0026). In the FLE group, the intraoperative new propagation length was (235.80 ± 84.94) mm. The FL propagation length at the 1-month follow-up was significantly longer than that measured intraoperatively (P = 0.0362). Histological evaluation demonstrated that the elastic fibres in the media layer of the aortic wall were disrupted and appeared to be significantly stretched on the adventitial side of the false lumen. CONCLUSIONS Our endovascular reintervention is a reliable, minimally invasive approach for producing specific TBAD models with different morphologies.
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Affiliation(s)
- Baolei Guo
- Department of Vascular Surgery, Zhongshan Hospital, Institute of Vascular Surgery, Fudan University, Shanghai, China
- National Clinical Research Center for Interventional Medicine, Shanghai, China
- Fudan Zhangjiang Institute, Shanghai, China
| | - Riaz Akhtar
- Department of Mechanical, Materials and Aerospace Engineering, School of Engineering, University of Liverpool, Liverpool, UK
| | - Haofei Liu
- Department of Mechanics, Tianjin University, Tianjin, China
| | - Cheng Yan
- National Clinical Research Center for Interventional Medicine, Shanghai, China
- Department of Radiology, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Daqiao Guo
- Department of Vascular Surgery, Zhongshan Hospital, Institute of Vascular Surgery, Fudan University, Shanghai, China
- National Clinical Research Center for Interventional Medicine, Shanghai, China
| | - Benjamin Patterson
- Department of Vascular Surgery, University Hospital Southampton, Southampton, UK
| | - Weiguo Fu
- Department of Vascular Surgery, Zhongshan Hospital, Institute of Vascular Surgery, Fudan University, Shanghai, China
- National Clinical Research Center for Interventional Medicine, Shanghai, China
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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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Aigner P, Sella Bart E, Panfili S, Körner T, Mach M, Andreas M, Königshofer M, Saitta S, Redaelli A, Schmid A, Moscato F. Quantification of paravalvular leaks associated with TAVI implants using 4D MRI in an aortic root phantom made possible by the use of 3D printing. Front Cardiovasc Med 2023; 10:1083300. [PMID: 36742071 PMCID: PMC9894656 DOI: 10.3389/fcvm.2023.1083300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Accepted: 01/02/2023] [Indexed: 01/21/2023] Open
Abstract
Introduction Transcatheter aortic valve implantation (TAVI) has become an alternative to surgical replacement of the aortic valve elderly patients. However, TAVI patients may suffer from paravalvular leaks (PVL). Detecting and grading is usually done by echocardiography, but is limited by resolution, 2D visualization and operator dependency. 4D flow magnetic resonance imaging (MRI) is a promising alternative, which did not reach clinical application in TAVI patients. The aim of this study was applying 3D printing technologies in order to evaluate flow patterns and hemodynamics of PVLs following TAVI, exploiting 4D flow MRI and standard ultrasound. Materials and methods An MR-compatible, anatomically left ventricle, aortic root, and ascending aorta model was fabricated by combining 3D-printed parts and various soft silicone materials to match physiological characteristics. An Abbott Portico™ valve was used in continuous antegrade flow (12-22 l/min), retrograde flow with varying transvalvular pressures (60-110 mmHg), and physiological pulsatile hemodynamics (aortic pressure: 120/80 mmHg, cardiac output: 5 l/min) Time-resolved MR measurements were performed above and below the TAVI stent and compared with color Doppler ultrasound measurements in exactly the same setup. Results The continuous antegrade flow measurements from MRI largely agreed with the flowmeter measurements, and a maximum error of only 7% was observed. In the retrograde configuration, visualization of the paravalvular leaks was possible from the MR measurements, but flow was overestimated by up to 33%. The 4D MRI measurement in the pulsatile setup revealed a single main PVL, which was also confirmed by the color Doppler measurements, and velocities were similar (2.0 m/s vs. 1.7 m/s). Discussion 4D MRI techniques were used to qualitatively assess flow in a patient-specific, MR-compatible and flexible model, which only became possible through the use of 3D printing techniques. Flow patterns in the ascending aorta, identification and quantification of PVLs was possible and the location and extent of PVLs were confirmed by ultrasound measurements. The 4D MRI flow technique allowed evaluation of flow patterns in the ascending aorta and the left ventricle below the TAVI stent with good results in identifying PVLs, demonstrating its capabilities over ultrasound by providing the ability to visualize the paravalvular jets in three dimensions at however, additional expenditure of time and money.
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Affiliation(s)
- Philipp Aigner
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria,Ludwig Boltzmann Institute for Cardiovascular Research, Vienna, Austria,*Correspondence: Philipp Aigner,
| | - Eleonora Sella Bart
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria,Department of Electronics, Information, and Bioengineering, Politecnico di Milano, Milan, Italy
| | - Sebastiano Panfili
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria,Department of Electronics, Information, and Bioengineering, Politecnico di Milano, Milan, Italy
| | - Tito Körner
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Markus Mach
- Department of Cardiac Surgery, Medical University of Vienna, Vienna, Austria
| | - Martin Andreas
- Department of Cardiac Surgery, Medical University of Vienna, Vienna, Austria
| | - Markus Königshofer
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Simone Saitta
- Department of Electronics, Information, and Bioengineering, Politecnico di Milano, Milan, Italy
| | - Alberto Redaelli
- Department of Electronics, Information, and Bioengineering, Politecnico di Milano, Milan, Italy
| | - Albrecht Schmid
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Francesco Moscato
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria,Ludwig Boltzmann Institute for Cardiovascular Research, Vienna, Austria,Austrian Cluster for Tissue Regeneration, Vienna, Austria
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Osztrogonacz P, Berczeli M, Chinnadurai P, Chang SM, Shah DJ, Lumsden AB. Dynamic Imaging of Aortic Pathologies: Review of Clinical Applications and Imaging Protocols. Methodist Debakey Cardiovasc J 2023; 19:4-14. [PMID: 36910554 PMCID: PMC10000327 DOI: 10.14797/mdcvj.1172] [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: 12/15/2022] [Accepted: 12/15/2022] [Indexed: 03/09/2023] Open
Abstract
The past decade has seen significant advances in dynamic imaging of the aorta. Today's vascular surgeons have the opportunity to choose from a wide array of imaging modalities to evaluate different aortic pathologies. While vascular ultrasound and aortography are considered to be the bread and butter imaging modalities, newer dynamic imaging techniques provide time-resolved information in various aortic pathologies. However, despite growing evidence of their advantages in the literature, they have not been routinely adopted. In order to understand the role of these emerging modalities, one must understand their principles, advantages, and limitations in the context of various clinical scenarios. In this review, we provide an overview of dynamic imaging techniques for aortic pathologies and describe various dynamic computed tomography and magnetic resonance imaging protocols, clinical applications, and potential future directions.
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Affiliation(s)
- Peter Osztrogonacz
- Houston Methodist Hospital, Houston, Texas, US.,Semmelweis University, Budapest, Hungary
| | - Marton Berczeli
- Houston Methodist Hospital, Houston, Texas, US.,Semmelweis University, Budapest, Hungary
| | - Ponraj Chinnadurai
- Houston Methodist Hospital, Houston, Texas, US.,Siemens Medical Solutions USA Inc., Malvern, Pennsylvania, US
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Takehara Y. Clinical Application of 4D Flow MR Imaging for the Abdominal Aorta. Magn Reson Med Sci 2022; 21:354-364. [PMID: 35185062 PMCID: PMC9680546 DOI: 10.2463/mrms.rev.2021-0156] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2021] [Accepted: 01/05/2022] [Indexed: 07/30/2023] Open
Abstract
Blood vessels can be regarded as autonomous organs. The endothelial cells on the vessel surface serve as mechanosensors or mechanoreceptors for the flow velocity and turbulence of the blood flow in terms of wall shear stress (WSS), thereby monitoring changes in the flow velocity. Accordingly, the endothelial cells regulate the flow velocity by releasing numerous mediators. Such regulatory systems also trigger atherosclerosis, where the WSS decreases or fluctuates to maintain the flow velocity or local WSS. As occurrences of abdominal aortic aneurysms and aortic dissection are closely related to atherosclerosis, understanding the hemodynamics of the abdominal aorta is necessary to obtain useful information concerning the pathogenesis, diagnosis, and interventions. 4D flow MRI is beneficial for measuring the hemodynamics through comprehensive retrospective flowmetry of the entire spatio-temporal distributions of the flow vectors. This section focuses on abdominal aortic aneurysms and aortic dissection as representative examples of abdominal aortic diseases. Their hemodynamic characteristics and how hemodynamics is involved in their progression are described, and how 4D flow MRI can contribute to their assessment is also explained.
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Affiliation(s)
- Yasuo Takehara
- Departments of Fundamental Development for Low Invasive Diagnostic Imaging and Radiology, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
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