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Sun C, Qin T, Kalyanasundaram A, Elefteriades J, Sun W, Liang L. Biomechanical stress analysis of Type-A aortic dissection at pre-dissection, post-dissection, and post-repair states. Comput Biol Med 2025; 184:109310. [PMID: 39515268 PMCID: PMC11663132 DOI: 10.1016/j.compbiomed.2024.109310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2024] [Revised: 08/05/2024] [Accepted: 10/18/2024] [Indexed: 11/16/2024]
Abstract
Acute type A aortic dissection remains a deadly and elusive condition, with risk factors such as hypertension, bicuspid aortic valves, and genetic predispositions. As existing guidelines for surgical intervention based solely on aneurysm diameter face scrutiny, there is a growing need to consider other predictors and parameters, including wall stress, in assessing dissection risk. Through our research, we aim to elucidate the biomechanical underpinnings of aortic dissection and provide valuable insights into its prediction and prevention. We applied finite element analysis (FEA) to assess stress distribution on a rare dataset comprising computed tomography (CT) images obtained from eight patients at three stages of aortic dissection: pre-dissection (preD), post-dissection (postD), and post-repair (postR). Our findings reveal significant increases in both mean and peak aortic wall stresses during the transition from the preD state to the postD state, reflecting the mechanical impact of dissection. Surgical repair effectively restores aortic wall diameter to pre-dissection levels, documenting its effectiveness in mitigating further complications. Furthermore, we identified stress concentration regions within the aortic wall that closely correlated with observed dissection borders, offering insights into high-risk areas. This study demonstrates the importance of considering biomechanical factors when assessing aortic dissection risk. Despite some limitations, such as uniform wall thickness assumptions and the absence of dynamic blood flow considerations, our patient-specific FEA approach provides valuable mechanistic insights into aortic dissection. These findings hold promise for improving predictive models and informing clinical decisions to enhance patient care.
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Affiliation(s)
| | | | - Asanish Kalyanasundaram
- Aortic Institute at Yale-New Haven Hospital, Yale University School of Medicine, New Haven, CT, USA
| | - John Elefteriades
- Aortic Institute at Yale-New Haven Hospital, Yale University School of Medicine, New Haven, CT, USA
| | - Wei Sun
- Sutra Medical Inc, Lake Forest, CA, USA
| | - Liang Liang
- Department of Computer Science, University of Miami, Coral Gables, FL, USA.
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Hussain A, Bilal S, Arshad T, Riaz Dar MN, Ahmed Aljohani A, Riaz MB, Ghith E. Unveiling thermal and hemodynamic effects of aneurysm on abdominal aorta using power law model and finite element analysis. CASE STUDIES IN THERMAL ENGINEERING 2024; 60:104746. [DOI: 10.1016/j.csite.2024.104746] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2025]
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Khabaz K, Yuan K, Pugar J, Jiang D, Sankary S, Dhara S, Kim J, Kang J, Nguyen N, Cao K, Washburn N, Bohr N, Lee CJ, Kindlmann G, Milner R, Pocivavsek L. The geometric evolution of aortic dissections: Predicting surgical success using fluctuations in integrated Gaussian curvature. PLoS Comput Biol 2024; 20:e1011815. [PMID: 38306397 PMCID: PMC10866512 DOI: 10.1371/journal.pcbi.1011815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Revised: 02/14/2024] [Accepted: 01/09/2024] [Indexed: 02/04/2024] Open
Abstract
Clinical imaging modalities are a mainstay of modern disease management, but the full utilization of imaging-based data remains elusive. Aortic disease is defined by anatomic scalars quantifying aortic size, even though aortic disease progression initiates complex shape changes. We present an imaging-based geometric descriptor, inspired by fundamental ideas from topology and soft-matter physics that captures dynamic shape evolution. The aorta is reduced to a two-dimensional mathematical surface in space whose geometry is fully characterized by the local principal curvatures. Disease causes deviation from the smooth bent cylindrical shape of normal aortas, leading to a family of highly heterogeneous surfaces of varying shapes and sizes. To deconvolute changes in shape from size, the shape is characterized using integrated Gaussian curvature or total curvature. The fluctuation in total curvature (δK) across aortic surfaces captures heterogeneous morphologic evolution by characterizing local shape changes. We discover that aortic morphology evolves with a power-law defined behavior with rapidly increasing δK forming the hallmark of aortic disease. Divergent δK is seen for highly diseased aortas indicative of impending topologic catastrophe or aortic rupture. We also show that aortic size (surface area or enclosed aortic volume) scales as a generalized cylinder for all shapes. Classification accuracy for predicting aortic disease state (normal, diseased with successful surgery, and diseased with failed surgical outcomes) is 92.8±1.7%. The analysis of δK can be applied on any three-dimensional geometric structure and thus may be extended to other clinical problems of characterizing disease through captured anatomic changes.
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Affiliation(s)
- Kameel Khabaz
- Department of Surgery, The University of Chicago, Chicago, Illinois, United States of America
| | - Karen Yuan
- Department of Surgery, The University of Chicago, Chicago, Illinois, United States of America
| | - Joseph Pugar
- Department of Surgery, The University of Chicago, Chicago, Illinois, United States of America
- Departments of Material Science and Engineering, Biomedical Engineering, and Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States of America
| | - David Jiang
- Department of Surgery, The University of Chicago, Chicago, Illinois, United States of America
| | - Seth Sankary
- Department of Surgery, The University of Chicago, Chicago, Illinois, United States of America
| | - Sanjeev Dhara
- Department of Surgery, The University of Chicago, Chicago, Illinois, United States of America
| | - Junsung Kim
- Department of Surgery, The University of Chicago, Chicago, Illinois, United States of America
| | - Janet Kang
- Department of Surgery, The University of Chicago, Chicago, Illinois, United States of America
| | - Nhung Nguyen
- Department of Surgery, The University of Chicago, Chicago, Illinois, United States of America
| | - Kathleen Cao
- Department of Surgery, The University of Chicago, Chicago, Illinois, United States of America
| | - Newell Washburn
- Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States of America
| | - Nicole Bohr
- Department of Surgery, The University of Chicago, Chicago, Illinois, United States of America
| | - Cheong Jun Lee
- Department of Surgery, NorthShore University Health System, Evanston, Illinois, United States of America
| | - Gordon Kindlmann
- Department of Computer Science, The University of Chicago, Chicago, Illinois, United States of America
| | - Ross Milner
- Department of Surgery, The University of Chicago, Chicago, Illinois, United States of America
| | - Luka Pocivavsek
- Department of Surgery, The University of Chicago, Chicago, Illinois, United States of America
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Cosentino F, Sherifova S, Sommer G, Raffa G, Pilato M, Pasta S, Holzapfel GA. Regional biomechanical characterization of human ascending aortic aneurysms: Microstructure and biaxial mechanical response. Acta Biomater 2023; 169:107-117. [PMID: 37579911 DOI: 10.1016/j.actbio.2023.08.016] [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: 04/06/2023] [Revised: 07/17/2023] [Accepted: 08/09/2023] [Indexed: 08/16/2023]
Abstract
The ascending thoracic aortic aneurysm (ATAA) is a permanent dilatation of the vessel with a high risk of adverse events, and shows heterogeneous properties. To investigate regional differences in the biomechanical properties of ATAAs, tissue samples were collected from 10 patients with tricuspid aortic valve phenotype and specimens from minor, anterior, major, and posterior regions were subjected to multi-ratio planar biaxial extension tests and second-harmonic generation (SHG) imaging. Using the data, parameters of a microstructure-motivated constitutive model were obtained considering fiber dispersion. SHG imaging showed disruptions in the organization of the layers. Structural and material parameters did not differ significantly between regions. The non-symmetric fiber dispersion model proposed by Holzapfel et al. [25] was used to fit the data. The mean angle of collagen fibers was negatively correlated between minor and anterior regions, and the parameter associated with collagen fiber stiffness was positively correlated between minor and major regions. Furthermore, correlations were found between the stiffness of the ground matrix and the mean fiber angle, and between the parameter associated with the collagen fiber stiffness and the out-of-plane dispersion parameter in the posterior and minor regions, respectively. The experimental data collected in this study contribute to the biomechanical data available in the literature on human ATAAs. Region-specific parameters for the constitutive models are fundamental to improve the current risk stratification strategies, which are mainly based on aortic size. Such investigations can facilitate the development of more advanced finite element models capable of capturing the regional heterogeneity of pathological tissues. STATEMENT OF SIGNIFICANCE: Tissue samples of human ascending thoracic aortic aneurysms (ATAA) were collected. Samples from four regions underwent multi-ratio planar biaxial extension tests and second-harmonic generation imaging. Region-specific parameters of a microstructure-motivated model considering fiber dispersion were obtained. Structural and material parameters did not differ significantly between regions, however, the mean fiber angle was negatively correlated between minor and anterior regions, and the parameter associated with collagen fiber stiffness was positively correlated between minor and major regions. Furthermore, correlations were found between the stiffness of the ground matrix and the mean fiber angle, and between the parameter associated with the collagen fiber stiffness and the out-of-plane dispersion parameter in the posterior and minor regions, respectively. This study provides a unique set of mechanical and structural data, supporting the microstructural influence on the tissue response. It may facilitate the development of better finite element models capable of capturing the regional tissue heterogeneity.
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Affiliation(s)
- Federica Cosentino
- Ri.MED Foundation, Palermo, Italy; Department of Engineering, University of Palermo, Italy
| | - Selda Sherifova
- Institute of Biomechanics, Graz University of Technology, Austria
| | - Gerhard Sommer
- Institute of Biomechanics, Graz University of Technology, Austria
| | - Giuseppe Raffa
- Department for the Treatment and Study of Cardiothoracic Diseases and Cardiothoracic Transplantation, IRCCS-ISMETT, Palermo, Italy
| | - Michele Pilato
- Department for the Treatment and Study of Cardiothoracic Diseases and Cardiothoracic Transplantation, IRCCS-ISMETT, Palermo, Italy
| | - Salvatore Pasta
- Department of Engineering, University of Palermo, Italy; Department for the Treatment and Study of Cardiothoracic Diseases and Cardiothoracic Transplantation, IRCCS-ISMETT, Palermo, Italy
| | - Gerhard A Holzapfel
- Institute of Biomechanics, Graz University of Technology, Austria; Department of Structural Engineering, Norwegian Institute of Science and Technology (NTNU), Trondheim, Norway.
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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: 14] [Impact Index Per Article: 7.0] [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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Kim T, Tjahjadi NS, He X, van Herwaarden JA, Patel HJ, Burris NS, Figueroa CA. Three-Dimensional Characterization of Aortic Root Motion by Vascular Deformation Mapping. J Clin Med 2023; 12:4471. [PMID: 37445507 DOI: 10.3390/jcm12134471] [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: 06/05/2023] [Revised: 06/29/2023] [Accepted: 07/02/2023] [Indexed: 07/15/2023] Open
Abstract
The aorta is in constant motion due to the combination of cyclic loading and unloading with its mechanical coupling to the contractile left ventricle (LV) myocardium. This aortic root motion has been proposed as a marker for aortic disease progression. Aortic root motion extraction techniques have been mostly based on 2D image analysis and have thus lacked a rigorous description of the different components of aortic root motion (e.g., axial versus in-plane). In this study, we utilized a novel technique termed vascular deformation mapping (VDM(D)) to extract 3D aortic root motion from dynamic computed tomography angiography images. Aortic root displacement (axial and in-plane), area ratio and distensibility, axial tilt, aortic rotation, and LV/Ao angles were extracted and compared for four different subject groups: non-aneurysmal, TAA, Marfan, and repair. The repair group showed smaller aortic root displacement, aortic rotation, and distensibility than the other groups. The repair group was also the only group that showed a larger relative in-plane displacement than relative axial displacement. The Marfan group showed the largest heterogeneity in aortic root displacement, distensibility, and age. The non-aneurysmal group showed a negative correlation between age and distensibility, consistent with previous studies. Our results revealed a strong positive correlation between LV/Ao angle and relative axial displacement and a strong negative correlation between LV/Ao angle and relative in-plane displacement. VDM(D)-derived 3D aortic root motion can be used in future studies to define improved boundary conditions for aortic wall stress analysis.
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Affiliation(s)
- Taeouk Kim
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
| | - Nic S Tjahjadi
- Department of Cardiac Surgery, University of Michigan, Ann Arbor, MI 48109, USA
| | - Xuehuan He
- Department of Radiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - J A van Herwaarden
- Department of Vascular Surgery, University Medical Center Utrecht, 3584 CX Utrecht, The Netherlands
| | - Himanshu J Patel
- Department of Cardiac Surgery, University of Michigan, Ann Arbor, MI 48109, USA
| | - Nicholas S Burris
- Department of Radiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - C Alberto Figueroa
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Surgery, University of Michigan, Ann Arbor, MI 48109, USA
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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: 1.0] [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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Wen J, Huang H, Su Z, Jiang L, Gao Q, Chen X, Yan T, Peng L. Predicting the Risk of Type B Aortic Dissection Using Hemodynamic Parameters in Aortic Arches: A Comparative Study between Healthy and Repaired Aortas. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2023; 230:107326. [PMID: 36608431 DOI: 10.1016/j.cmpb.2022.107326] [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: 09/03/2022] [Revised: 11/19/2022] [Accepted: 12/24/2022] [Indexed: 06/17/2023]
Abstract
BACKGROUND AND OBJECTIVE The development of acute aortic dissection (AD) remains unpredictable due to the intricate nature of the AD mechanism and the varied patient-specific aortic anatomy. The aim of this study was to simulate the hemodynamic parameters in the aortas before the onset of TBAD with healthy controls. METHODS This study numerically assessed the effectiveness of hemodynamic indicators in predicting the risk of type B AD (TBAD) by investigating the differences in hemodynamic parameters between healthy and repaired aortas (aortas before TBAD development). Four wall shear stress (WSS)-based indicators and three helicity-based indicators were adopted and analyzed. RESULTS The results showed that more pathological anatomical feathers can be observed in the repaired aortas. For WSS-based indicators, only averaged cross flow index (CFI) and oscillatory shear index OSI (CFI, 1.03 ± 0.07 vs. 0.83 ± 0.10 and OSI, 0.12 ± 0.03 vs. 0.04 ± 0.02) (all p<0.001) were significantly higher in the repaired aortas than those in the healthy aortas. On the other hand, average helicity in the repaired aortas also showed a significant difference compared with that in healthy aortas (h1, 3.88 ± 5.55 vs. -8.03 ± 14.16) (p<0.05). Furthermore, the skewed helical structure and flow disturbance was found in the repaired aortas. CONCLUSION 1) There are marked differences in pathological anatomical features, such as aortic dilation, elongation and tortuosity between the healthy aortas and repaired aortas, and the corresponding hemodynamic indicators also have also been significantly changed. 2) Compared with anatomical characteristics, hemodynamic indicators may be more accurate for predicting the risk and location of TBAD, such as the OSI and CFI index were significantly enhanced in the region where the entry tears have occurred. 3) In clinical practice, anatomical features remain important factors for assessing the risk for development of TBAD; however, hemodynamic analyses with quantitative data and more visualizing characteristics have showed promising potential in this aspect.
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Affiliation(s)
- Jun Wen
- Department of Computer Science and technology, Southwest University of Science and Technology, Mianyang 621010, China
| | - Haodi Huang
- Institute of Civil Engineering and Architecture, Southwest University of Science and Technology, Mianyang 621010, China
| | - Zhiqiao Su
- Institute of Civil Engineering and Architecture, Southwest University of Science and Technology, Mianyang 621010, China
| | - Linke Jiang
- Institute of Civil Engineering and Architecture, Southwest University of Science and Technology, Mianyang 621010, China
| | - Qi Gao
- Institute of Civil Engineering and Architecture, Southwest University of Science and Technology, Mianyang 621010, China
| | - Xiaoyi Chen
- Department of Radiology, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Tingli Yan
- Department of Radiology, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Liqing Peng
- Department of Radiology, West China Hospital, Sichuan University, Chengdu 610041, China.
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9
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Gomez A, Wang Z, Xuan Y, Hope MD, Saloner DA, Guccione JM, Ge L, Tseng EE. Association of diameter and wall stresses of tricuspid aortic valve ascending thoracic aortic aneurysms. J Thorac Cardiovasc Surg 2022; 164:1365-1375. [PMID: 34275618 PMCID: PMC8716675 DOI: 10.1016/j.jtcvs.2021.05.049] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 05/17/2021] [Accepted: 05/21/2021] [Indexed: 12/27/2022]
Abstract
OBJECTIVE Ascending thoracic aortic aneurysms carry a risk of acute type A dissection. Elective repair guidelines are designed around size thresholds, but the 1-dimensional parameter of maximum diameter cannot predict acute events in small aneurysms. Biomechanically, dissection can occur when wall stress exceeds strength. Patient-specific ascending thoracic aortic aneurysm wall stresses may be a better predictor of dissection. Our aim was to compare wall stresses in tricuspid aortic valve-associated ascending thoracic aortic aneurysms based on diameter. METHODS Patients with tricuspid aortic valve-associated ascending thoracic aortic aneurysm and diameter 4.0 cm or greater (n = 221) were divided into groups by 0.5-cm diameter increments. Three-dimensional geometries were reconstructed from computed tomography images, and finite element models were developed taking into account prestress geometries. A fiber-embedded hyperelastic material model was applied to obtain longitudinal and circumferential wall stress distributions under systolic pressure. Median stresses with interquartile ranges were determined. The Kruskal-Wallis test was used for comparisons between size groups. RESULTS Peak longitudinal wall stresses for tricuspid aortic valve-associated ascending thoracic aortic aneurysm were 290 (265-323) kPa for size 4.0 to 4.4 cm versus 330 (296-359) kPa for 4.5 to 4.9 cm versus 339 (320-373) kPa for 5.0 to 5.4 cm versus 318 (293-351) kPa for 5.5 to 5.9 cm versus 373 (363-449) kPa for 6.0 cm or greater (P = 8.7e-8). Peak circumferential wall stresses were 460 (421-543) kPa for size 4.0 to 4.4 cm versus 503 (453-569) kPa for 4.5 to 4.9 cm versus 549 (430-588) kPa for 5.0 to 5.4 cm versus 540 (471-608) kPa for 5.5 to 5.9 cm versus 596 (506-649) kPa for 6.0 cm or greater (P = .0007). CONCLUSIONS Circumferential and longitudinal wall stresses are higher as diameter increases, but size groups had large overlap of stress ranges. Wall stress thresholds based on aneurysm wall strength may be a better predictor of patient-specific risk of dissection than diameter in small ascending thoracic aortic aneurysms.
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Affiliation(s)
- Axel Gomez
- Division of Adult Cardiothoracic Surgery, Department of Surgery, University of California San Francisco and San Francisco VA Medical Center, San Francisco, Calif
| | - Zhongjie Wang
- Division of Adult Cardiothoracic Surgery, Department of Surgery, University of California San Francisco and San Francisco VA Medical Center, San Francisco, Calif
| | - Yue Xuan
- Division of Adult Cardiothoracic Surgery, Department of Surgery, University of California San Francisco and San Francisco VA Medical Center, San Francisco, Calif
| | - Michael D Hope
- Department of Radiology & Biomedical Imaging, University of California San Francisco and San Francisco VA Medical Center, San Francisco, Calif
| | - David A Saloner
- Department of Radiology & Biomedical Imaging, University of California San Francisco and San Francisco VA Medical Center, San Francisco, Calif
| | - Julius M Guccione
- Division of Adult Cardiothoracic Surgery, Department of Surgery, University of California San Francisco and San Francisco VA Medical Center, San Francisco, Calif
| | - Liang Ge
- Division of Adult Cardiothoracic Surgery, Department of Surgery, University of California San Francisco and San Francisco VA Medical Center, San Francisco, Calif
| | - Elaine E Tseng
- Division of Adult Cardiothoracic Surgery, Department of Surgery, University of California San Francisco and San Francisco VA Medical Center, San Francisco, Calif.
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10
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Sun L, Li X, Wang G, Sun J, Zhang X, Chi H, Cao H, Ma W, Yan Z, Liu G. Relationship Between Length and Curvature of Ascending Aorta and Type a Dissection. Front Cardiovasc Med 2022; 9:927105. [PMID: 35795370 PMCID: PMC9251172 DOI: 10.3389/fcvm.2022.927105] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2022] [Accepted: 05/30/2022] [Indexed: 11/17/2022] Open
Abstract
Background Type A aortic dissection (TAAD) has a rapid onset and high mortality. Currently, aortic diameter is the major criterion for evaluating the risk of TAAD. We attempted to find other aortic morphological indicators to further analyze their relationships with the risk of type A dissection. Methods We included the imaging and clinical data of 112 patients. The patients were divided into three groups, of which Group 1 had 49 patients with normal aortic diameter, Group 2 had 22 patients with ascending aortic aneurysm, and Group 3 had 41 patients with TAAD. We used AW Server software, version 3.2, to measure aorta-related morphological indicators. Results First, in Group 1, the univariate analysis results showed that ascending aortic diameter was correlated with patient age (r2 = 0.35) and ascending aortic length (AAL) (r2 = 0.43). AAL was correlated with age (r2 = 0.12) and height (r2 = 0.11). Further analysis of the aortic morphological indicators among the three groups found that the median aortic diameter was 36.20 mm in Group 1 (Q1–Q3: 33.40–37.70 mm), 42.5 mm in Group 2 (Q1–Q3: 41.52–44.17 mm) and 48.6 mm in Group 3 (Q1–Q3: 42.4–55.3 mm). There was no significant difference between Groups 2 and 3 (P > 0.05). Group 3 had the longest AAL (median: 109.4 mm, Q1–Q3: 118.3–105.3 mm), followed by Group 2 (median: 91.0 mm, Q1–Q3: 95.97–84.12 mm) and Group 1 (81.20 mm, Q1–Q3: 76.90–86.20 mm), and there were statistically significant differences among the three groups (P < 0.05). The Aortic Bending Index (ABI) was 14.95 mm/cm in Group 3 (Q1–Q3: 14.42–15.78 mm/cm), 13.80 mm/cm in Group 2 (Q1–Q3: 13.42–14.42 mm/cm), and 13.29 mm/cm in Group 1 (Q1–Q3: 12.71–13.78 mm/cm), and the difference was statistically significant in comparisons between any two groups (P < 0.05). Regression analysis showed that aortic diameter + AAL + ABI differentiated Group 2 and Group 3 with statistical significance (area under the curve (AUC) = 0.834), which was better than aortic diameter alone (AUC = 0.657; P < 0.05). Conclusions We introduced the new concept of ABI, which has certain clinical significance in distinguishing patients with aortic dissection and aneurysm. Perhaps the ascending aortic diameter combined with AAL and ABI could be helpful in predicting the occurrence of TAAD.
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Affiliation(s)
- Lianjie Sun
- Department of Cardiovascular Surgery, The Affiliated Hospital of Qingdao University, Qingdao, China
| | - Xiao Li
- Department of Ultrasound in Medicine, Shanghai Jiao Tong University Affiliated 6th People's Hospital, Shanghai Institute of Ultrasound in Medicine, Shanghai, China
| | - Guoqing Wang
- Department of Cardiovascular Surgery, The Affiliated Hospital of Qingdao University, Qingdao, China
| | - Jianchao Sun
- Department of Cardiovascular Surgery, The Affiliated Hospital of Qingdao University, Qingdao, China
| | - Xiaoming Zhang
- Department of Cardiovascular Surgery, The Affiliated Hospital of Qingdao University, Qingdao, China
| | - Honghui Chi
- Department of Cardiovascular Surgery, The Affiliated Hospital of Qingdao University, Qingdao, China
| | - Huihui Cao
- Department of Cardiovascular Surgery, The Affiliated Hospital of Qingdao University, Qingdao, China
| | - Wanteng Ma
- Department of Cardiovascular Surgery, The Affiliated Hospital of Qingdao University, Qingdao, China
| | - Zhisheng Yan
- Department of Cardiovascular Surgery, The Affiliated Hospital of Qingdao University, Qingdao, China
| | - Gaoli Liu
- Department of Cardiovascular Surgery, The Affiliated Hospital of Qingdao University, Qingdao, China
- *Correspondence: Gaoli Liu
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11
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Wen J, Yan T, Su Z, Huang H, Gao Q, Chen X, Wong KKL, Peng L. Risk evaluation of type B aortic dissection based on WSS-based indicators distribution in different types of aortic arch. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2022; 221:106872. [PMID: 35594583 DOI: 10.1016/j.cmpb.2022.106872] [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: 02/07/2022] [Revised: 04/26/2022] [Accepted: 05/09/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND AND OBJECTIVE The underlying mechanism of aortic dissection (AD) remains unclear and the onset of AD is still unpredictable. Although clinical study with statistical analysis has reported that type III aortic arch may have strong correlation with type B AD (TBD), the effects of different arch types on the wall shear stress (WSS) have not been clarified. METHODS As a complementary work, this study numerically investigated the distribution of five WSS-based indicators in thirty aortic arches without AD, which were classified into three groups based on the arch types. RESULTS The distribution of most WSS indicators, such as time averaged WSS (TAWSS), oscillatory shear index (OSI) and relative residence time (RRT) had no significant difference among different types of aortic arches (P>0.05). However, a multidirectional WSS index, namely CFI, was found its maximum value was positively correlated with type III aortic arch in proximal descending aorta (p<0.001, r = 0.65). CONCLUSIONS It can be concluded that the enhancement or oscillation of WSS may not be the main reason of TBD is prevalence in type III arches, while the multidirectional WSS distribution may be an important factor. It can be further referred that the CFI may have a potential to predict the onset of TBD.
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Affiliation(s)
- Jun Wen
- Institute of Civil Engineering and Architecture, Southwest University of Science and Technology, Mianyang 621010, China
| | - Tingli Yan
- Department of Radiology, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Zhiqiao Su
- Institute of Civil Engineering and Architecture, Southwest University of Science and Technology, Mianyang 621010, China
| | - Haodi Huang
- Institute of Civil Engineering and Architecture, Southwest University of Science and Technology, Mianyang 621010, China
| | - Qi Gao
- Institute of Civil Engineering and Architecture, Southwest University of Science and Technology, Mianyang 621010, China
| | - Xiaoyi Chen
- Department of Radiology, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Kelvin K L Wong
- School of Computer Science and Engineering, Central South University, Changsha 410000, China.
| | - Liqing Peng
- Department of Radiology, West China Hospital, Sichuan University, Chengdu 610041, China.
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12
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Erkul S, Alptekin Erkul GS. Retrograde ascending aortic dissection in the midterm period after thoracic endovascular aortic repair: a case report and literature review. Acta Chir Belg 2022; 122:211-214. [PMID: 32674719 DOI: 10.1080/00015458.2020.1794340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Retrograde ascending aortic dissection (rAAD) is a catastrophic complication of thoracic endovascular aortic repair (TEVAR). A 56 year-old male patient who had undergone TEVAR for Stanford type B aortic dissection 6-month ago was admitted to our clinic with uncontrolled hypertension for the last twelve hours and history of a syncopal attack three days ago. Retrograde ascending aortic dissection was detected in computed tomography angiography. Ascending aorta and hemiarch replacement with a Dacron graft was safely performed via hypothermic circulatory arrest and antegrade cerebral perfusion for the treatment of rAAD after TEVAR.
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Affiliation(s)
- Sinan Erkul
- Cardiovascular Surgery Department, Kutahya University of Health Sciences Evliya Celebi Training and Research Hospital, Kutahya, Turkey
| | - Gulen Sezer Alptekin Erkul
- Cardiovascular Surgery Department, Kutahya University of Health Sciences Evliya Celebi Training and Research Hospital, Kutahya, Turkey
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13
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Gomez A, Wang Z, Xuan Y, Hope MD, Saloner DA, Guccione JM, Ge L, Tseng EE. Regional wall stress differences on tricuspid aortic valve-associated ascending aortic aneurysms. Interact Cardiovasc Thorac Surg 2022; 34:1115-1123. [PMID: 34718581 PMCID: PMC10634398 DOI: 10.1093/icvts/ivab269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Revised: 07/15/2021] [Accepted: 08/27/2021] [Indexed: 11/13/2022] Open
Abstract
OBJECTIVES Ascending thoracic aortic aneurysms (aTAAs) carry a risk of acute type A dissection. Elective repair guidelines are based on diameter, but complications often occur below diameter threshold. Biomechanically, dissection can occur when wall stress exceeds wall strength. Aneurysm wall stresses may better capture dissection risk. Our aim was to investigate patient-specific aTAA wall stresses associated with a tricuspid aortic valve (TAV) by anatomic region. METHODS Patients with aneurysm diameter ≥4.0 cm underwent computed tomography angiography. Aneurysm geometries were reconstructed and loaded to systemic pressure while taking prestress into account. Finite element analyses were conducted to obtain wall stress distributions. The 99th percentile longitudinal and circumferential stresses were determined at systole. Wall stresses between regions were compared using one-way analysis of variance with post hoc Tukey HSD for pairwise comparisons. RESULTS Peak longitudinal wall stresses on aneurysms (n = 204) were 326 [standard deviation (SD): 61.7], 246 (SD: 63.4) and 195 (SD: 38.7) kPa in sinuses of Valsalva, sinotubular junction (STJ) and ascending aorta (AscAo), respectively, with significant differences between AscAo and both sinuses (P < 0.001) and STJ (P < 0.001). Peak circumferential wall stresses were 416 (SD: 85.1), 501 (SD: 119) and 340 (SD: 57.6) kPa for sinuses, STJ and AscAo, respectively, with significant differences between AscAo and both sinuses (P < 0.001) and STJ (P < 0.001). CONCLUSIONS Circumferential and longitudinal wall stresses were greater in the aortic root than AscAo on aneurysm patients with a TAV. Aneurysm wall stress magnitudes and distribution relative to respective regional wall strength could improve understanding of aortic regions at greater risk of dissection in a particular patient.
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Affiliation(s)
- Axel Gomez
- Division of Adult Cardiothoracic Surgery, Department of Surgery, University of California San Francisco and San Francisco VA Medical Center, San Francisco, CA, USA
| | - Zhongjie Wang
- Division of Adult Cardiothoracic Surgery, Department of Surgery, University of California San Francisco and San Francisco VA Medical Center, San Francisco, CA, USA
| | - Yue Xuan
- Division of Adult Cardiothoracic Surgery, Department of Surgery, University of California San Francisco and San Francisco VA Medical Center, San Francisco, CA, USA
| | - Michael D Hope
- Department of Radiology, University of California San Francisco and San Francisco VA Medical Center, San Francisco, CA, USA
| | - David A Saloner
- Department of Radiology, University of California San Francisco and San Francisco VA Medical Center, San Francisco, CA, USA
| | - Julius M Guccione
- Division of Adult Cardiothoracic Surgery, Department of Surgery, University of California San Francisco and San Francisco VA Medical Center, San Francisco, CA, USA
| | - Liang Ge
- Division of Adult Cardiothoracic Surgery, Department of Surgery, University of California San Francisco and San Francisco VA Medical Center, San Francisco, CA, USA
| | - Elaine E Tseng
- Division of Adult Cardiothoracic Surgery, Department of Surgery, University of California San Francisco and San Francisco VA Medical Center, San Francisco, CA, USA
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14
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He Y, Northrup H, Le H, Cheung AK, Berceli SA, Shiu YT. Medical Image-Based Computational Fluid Dynamics and Fluid-Structure Interaction Analysis in Vascular Diseases. Front Bioeng Biotechnol 2022; 10:855791. [PMID: 35573253 PMCID: PMC9091352 DOI: 10.3389/fbioe.2022.855791] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2022] [Accepted: 04/08/2022] [Indexed: 01/17/2023] Open
Abstract
Hemodynamic factors, induced by pulsatile blood flow, play a crucial role in vascular health and diseases, such as the initiation and progression of atherosclerosis. Computational fluid dynamics, finite element analysis, and fluid-structure interaction simulations have been widely used to quantify detailed hemodynamic forces based on vascular images commonly obtained from computed tomography angiography, magnetic resonance imaging, ultrasound, and optical coherence tomography. In this review, we focus on methods for obtaining accurate hemodynamic factors that regulate the structure and function of vascular endothelial and smooth muscle cells. We describe the multiple steps and recent advances in a typical patient-specific simulation pipeline, including medical imaging, image processing, spatial discretization to generate computational mesh, setting up boundary conditions and solver parameters, visualization and extraction of hemodynamic factors, and statistical analysis. These steps have not been standardized and thus have unavoidable uncertainties that should be thoroughly evaluated. We also discuss the recent development of combining patient-specific models with machine-learning methods to obtain hemodynamic factors faster and cheaper than conventional methods. These critical advances widen the use of biomechanical simulation tools in the research and potential personalized care of vascular diseases.
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Affiliation(s)
- Yong He
- Division of Vascular Surgery and Endovascular Therapy, University of Florida, Gainesville, FL, United States
| | - Hannah Northrup
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, United States
- Division of Nephrology and Hypertension, Department of Internal Medicine, University of Utah, Salt Lake City, UT, United States
| | - Ha Le
- Division of Nephrology and Hypertension, Department of Internal Medicine, University of Utah, Salt Lake City, UT, United States
| | - Alfred K. Cheung
- Division of Nephrology and Hypertension, Department of Internal Medicine, University of Utah, Salt Lake City, UT, United States
- Veterans Affairs Salt Lake City Healthcare System, Salt Lake City, UT, United States
| | - Scott A. Berceli
- Division of Vascular Surgery and Endovascular Therapy, University of Florida, Gainesville, FL, United States
- Vascular Surgery Section, Malcom Randall Veterans Affairs Medical Center, Gainesville, FL, United States
| | - Yan Tin Shiu
- Division of Nephrology and Hypertension, Department of Internal Medicine, University of Utah, Salt Lake City, UT, United States
- Veterans Affairs Salt Lake City Healthcare System, Salt Lake City, UT, United States
- *Correspondence: Yan Tin Shiu,
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15
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Yin M, Ban E, Rego BV, Zhang E, Cavinato C, Humphrey JD, Em Karniadakis G. Simulating progressive intramural damage leading to aortic dissection using DeepONet: an operator-regression neural network. J R Soc Interface 2022; 19:20210670. [PMID: 35135299 PMCID: PMC8826120 DOI: 10.1098/rsif.2021.0670] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Accepted: 12/23/2021] [Indexed: 12/28/2022] Open
Abstract
Aortic dissection progresses mainly via delamination of the medial layer of the wall. Notwithstanding the complexity of this process, insight has been gleaned by studying in vitro and in silico the progression of dissection driven by quasi-static pressurization of the intramural space by fluid injection, which demonstrates that the differential propensity of dissection along the aorta can be affected by spatial distributions of structurally significant interlamellar struts that connect adjacent elastic lamellae. In particular, diverse histological microstructures may lead to differential mechanical behaviour during dissection, including the pressure-volume relationship of the injected fluid and the displacement field between adjacent lamellae. In this study, we develop a data-driven surrogate model of the delamination process for differential strut distributions using DeepONet, a new operator-regression neural network. This surrogate model is trained to predict the pressure-volume curve of the injected fluid and the damage progression within the wall given a spatial distribution of struts, with in silico data generated using a phase-field finite-element model. The results show that DeepONet can provide accurate predictions for diverse strut distributions, indicating that this composite branch-trunk neural network can effectively extract the underlying functional relationship between distinctive microstructures and their mechanical properties. More broadly, DeepONet can facilitate surrogate model-based analyses to quantify biological variability, improve inverse design and predict mechanical properties based on multi-modality experimental data.
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Affiliation(s)
- Minglang Yin
- Center for Biomedical Engineering, Brown University, Providence, RI 02912, USA
- School of Engineering, Brown University, Providence, RI 02912, USA
| | - Ehsan Ban
- Department of Biomedical Engineering, Yale University, New Haven, CT 06520, USA
| | - Bruno V. Rego
- Department of Biomedical Engineering, Yale University, New Haven, CT 06520, USA
| | - Enrui Zhang
- Division of Applied Mathematics, Brown University, Providence, RI 02912, USA
| | - Cristina Cavinato
- Department of Biomedical Engineering, Yale University, New Haven, CT 06520, USA
| | - Jay D. Humphrey
- Department of Biomedical Engineering, Yale University, New Haven, CT 06520, USA
| | - George Em Karniadakis
- School of Engineering, Brown University, Providence, RI 02912, USA
- Division of Applied Mathematics, Brown University, Providence, RI 02912, USA
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16
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Patient-Specific Analysis of Ascending Thoracic Aortic Aneurysm with the Living Heart Human Model. Bioengineering (Basel) 2021; 8:bioengineering8110175. [PMID: 34821741 PMCID: PMC8615119 DOI: 10.3390/bioengineering8110175] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 10/26/2021] [Accepted: 11/03/2021] [Indexed: 01/11/2023] Open
Abstract
In ascending thoracic aortic aneurysms (ATAAs), aneurysm kinematics are driven by ventricular traction occurring every heartbeat, increasing the stress level of dilated aortic wall. Aortic elongation due to heart motion and aortic length are emerging as potential indicators of adverse events in ATAAs; however, simulation of ATAA that takes into account the cardiac mechanics is technically challenging. The objective of this study was to adapt the realistic Living Heart Human Model (LHHM) to the anatomy and physiology of a patient with ATAA to assess the role of cardiac motion on aortic wall stress distribution. Patient-specific segmentation and material parameter estimation were done using preoperative computed tomography angiography (CTA) and ex vivo biaxial testing of the harvested tissue collected during surgery. The lumped-parameter model of systemic circulation implemented in the LHHM was refined using clinical and echocardiographic data. The results showed that the longitudinal stress was highest in the major curvature of the aneurysm, with specific aortic quadrants having stress levels change from tensile to compressive in a transmural direction. This study revealed the key role of heart motion that stretches the aortic root and increases ATAA wall tension. The ATAA LHHM is a realistic cardiovascular platform where patient-specific information can be easily integrated to assess the aneurysm biomechanics and potentially support the clinical management of patients with ATAAs.
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17
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Hu H, Liu Z, Chen G, Yuan D, Zheng T. Analysis of aortic wall stress and morphology in patients with type B aortic dissection. MEDICINE IN NOVEL TECHNOLOGY AND DEVICES 2021. [DOI: 10.1016/j.medntd.2021.100081] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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18
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Han L, Ren Q, Lian J, Luo L, Liu H, Ma T, Li X, Deng X, Liu X. Numerical analysis of the hemodynamics of rat aorta based on magnetic resonance imaging and fluid-structure interaction. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2021; 37:e3457. [PMID: 33750033 DOI: 10.1002/cnm.3457] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 03/14/2021] [Indexed: 06/12/2023]
Abstract
Murine models have been widely used to investigate the mechanobiology of aortic atherosclerosis and dissections, which develop preferably at different anatomic locations of aorta. Based MRI and finite element analysis with fluid-structure interaction, we numerically investigated factors that may affect the blood flow and structural mechanics of rat aorta. The results indicated that aortic root motion greatly increases time-averaged wall shear stress (TAWSS), oscillatory shear index (OSI), relative residence time (RRT), displacement of the aorta, and enhances helical flow pattern but has limited influence on effective stress, which is highly modulated by blood pressure. Moreover, the influence of the motion component on these indicators is different with axial motion more obvious than planar motion. Surrounding fixation of the intercostal arteries and the branch vessels on aortic arch would reduce the influence of aortic root motion. The compliance of the aorta has different influences at different regions, leading to decrease in TAWSS and helical flow, increase in OSI, RRT at the aortic arch, but has reversed effects on the branch vessels. When compared with the steady flow, the pulsatile blood flow would obviously increase the WSS, the displacement, and the effective stress in most regions. In conclusion, to accurately quantify the blood flow and structural mechanics of rat aorta, the motion of the aortic root, the compliance of aortic wall, and the pulsation of blood flow should be considered. However, when only focusing on the effective stress in rat aorta, the motion of the aortic root may be neglected.
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Affiliation(s)
- Longzhu Han
- Beijing Advanced Innovation Centre for Biomedical Engineering, Key Laboratory for Biomechanics and Mechanobiology of the Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Quan Ren
- Beijing Advanced Innovation Centre for Biomedical Engineering, Key Laboratory for Biomechanics and Mechanobiology of the Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Jianxiu Lian
- Beijing Advanced Innovation Centre for Biomedical Engineering, Key Laboratory for Biomechanics and Mechanobiology of the Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Liyi Luo
- School of Instrumentation Science & Opto-electronics Engineering, Beihang University, Beijing, China
| | - Huawei Liu
- Department of Stomatology, Chinese PLA General Hospital, Beijing, China
| | - Tianxiang Ma
- Beijing Advanced Innovation Centre for Biomedical Engineering, Key Laboratory for Biomechanics and Mechanobiology of the Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Xin Li
- Miyun Hospital, Peking University First Hospital, Beijing, China
| | - Xiaoyan Deng
- Artificial Intelligence Key Laboratory of Sichuan Province, School of Automation and Information Engineering, Sichuan University of Science and Engineering, Zigong, China
| | - Xiao Liu
- Beijing Advanced Innovation Centre for Biomedical Engineering, Key Laboratory for Biomechanics and Mechanobiology of the Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
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19
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Czerny M, Rylski B, Della Corte A, Krüger T. Decision-making to perform elective surgery for patients with proximal thoracic aortic pathology: A European perspective. J Thorac Cardiovasc Surg 2021; 163:2025-2030. [PMID: 33781591 DOI: 10.1016/j.jtcvs.2021.01.141] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 01/13/2021] [Accepted: 01/22/2021] [Indexed: 12/17/2022]
Affiliation(s)
- Martin Czerny
- Department of Cardiovascular Surgery, University Heart Center Freiburg, Bad Krozingen, Germany; Faculty of Medicine, Albert Ludwigs University Freiburg, Freiburg, Germany.
| | - Bartosz Rylski
- Department of Cardiovascular Surgery, University Heart Center Freiburg, Bad Krozingen, Germany; Faculty of Medicine, Albert Ludwigs University Freiburg, Freiburg, Germany
| | - Alessandro Della Corte
- Department of Translational Medical Sciences, University of Campania "L. Vanvitelli," Cardiac Surgery Unit, Monaldi Hospital, Naples, Italy
| | - Tobias Krüger
- Department of Thoracic and Cardiovascular Surgery, University Medical Center, Tübingen, Germany
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20
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Brunet J, Pierrat B, Badel P. Review of Current Advances in the Mechanical Description and Quantification of Aortic Dissection Mechanisms. IEEE Rev Biomed Eng 2021; 14:240-255. [PMID: 31905148 DOI: 10.1109/rbme.2019.2950140] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Aortic dissection is a life-threatening event associated with a very poor outcome. A number of complex phenomena are involved in the initiation and propagation of the disease. Advances in the comprehension of the mechanisms leading to dissection have been made these last decades, thanks to improvements in imaging and experimental techniques. However, the micro-mechanics involved in triggering such rupture events remains poorly described and understood. It constitutes the primary focus of the present review. Towards the goal of detailing the dissection phenomenon, different experimental and modeling methods were used to investigate aortic dissection, and to understand the underlying phenomena involved. In the last ten years, research has tended to focus on the influence of microstructure on initiation and propagation of the dissection, leading to a number of multiscale models being developed. This review brings together all these materials in an attempt to identify main advances and remaining questions.
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21
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Subramaniam DR, Gutmark E, Andersen N, Nielsen D, Mortensen K, Gravholt C, Backeljauw P, Gutmark-Little I. Influence of Material Model and Aortic Root Motion in Finite Element Analysis of Two Exemplary Cases of Proximal Aortic Dissection. J Biomech Eng 2021; 143:014504. [PMID: 32793953 DOI: 10.1115/1.4048084] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2020] [Indexed: 01/25/2023]
Abstract
The risk of type-A dissection is increased in subjects with connective tissue disorders and dilatation of the proximal aorta. The location and extents of vessel wall tears in these patients could be potentially missed during prospective imaging studies. The objective of this study is to estimate the distribution of systolic wall stress in two exemplary cases of proximal dissection using finite element analysis (FEA) and evaluate the sensitivity of the distribution to the choice of anisotropic material model and root motion. FEA was performed for predissection aortas, without prior knowledge of the origin and extents of vessel wall tear. The stress distribution was evaluated along the wall tear in the postdissection aortas. The stress distribution was compared for the Fung and Holzapfel models with and without root motion. For the subject with spiral dissection, peak stress coincided with the origin of the tear in the sinotubular junction. For the case with root dissection, maximum stress was obtained at the distal end of the tear. The FEA predicted tear pressure was 20% higher for the subject with root dissection as compared to the case with spiral dissection. The predicted tear pressure was higher (9-11%) for root motions up to 10 mm. The Holzapfel model predicted a tear pressure that was lower (8-15%) than the Fung model. The FEA results showed that both material response and root motion could potentially influence the predicted dissection pressure of the proximal aorta at least for conditions tested in this study.
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Affiliation(s)
| | - Ephraim Gutmark
- Department of Aerospace Engineering and Engineering Mechanics, University of Cincinnati, Cincinnati, OH 45221-0070
| | - Niels Andersen
- Department of Cardiology, Aalborg University Hospital, Aalborg 9100, Denmark
| | - Dorte Nielsen
- Department of Cardiology, Aarhus University Hospital, Aarhus 8200, Denmark
| | - Kristian Mortensen
- Cardiorespiratory Unit, Great Ormond Street Hospital for Children, London WC1N 3JH, UK
| | - Claus Gravholt
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Aarhus 8200, Denmark
| | - Philippe Backeljauw
- Division of Endocrinology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229
| | - Iris Gutmark-Little
- Division of Endocrinology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229
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22
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Bondesson J, Suh GY, Lundh T, Dake MD, Lee JT, Cheng CP. Quantification of true lumen helical morphology and chirality in type B aortic dissections. Am J Physiol Heart Circ Physiol 2020; 320:H901-H911. [PMID: 33382638 DOI: 10.1152/ajpheart.00778.2020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Chirality is a fundamental property in many biological systems. Motivated by previous observations of helical aortic blood flow, aortic tissue fibers, and propagation of aortic dissections, we introduce methods to characterize helical morphology of aortic dissections. After validation on computer-generated phantoms, the methods were applied to patients with type B dissection. For this cohort, there was a distinct bimodal distribution of helical propagation of the dissection with either achiral or exclusively right-handed chirality, with no intermediate cases or left-handed cases. This clear grouping indicates that dissection propagation favors these two modes, which is potentially due to the right-handedness of helical aortic blood flow and cell orientation. The characterization of dissection chirality and quantification of helical morphology advances our understanding of dissection pathology and lays a foundation for applications in clinical research and treatment practice. For example, the chirality and magnitude of helical metrics of dissections may indicate risk of dissection progression, help define treatment and surveillance strategies, and enable development of novel devices that account for various helical morphologies.NEW & NOTEWORTHY A novel definition of helical propagation of type B aortic dissections reveals a distinct bimodality, with the true lumen being either achiral (nonhelical) or exclusively right-handed. This right-handed chirality is consistent with anatomic and physiological phenomena such as right-handed twist during left ventricle contraction, helical blood flow, and tissue fiber direction. The helical character of aortic dissections may be useful for pathology research, diagnostics, treatment selection, therapeutic durability prediction, and aortic device design.
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Affiliation(s)
- Johan Bondesson
- Division of Dynamics, Chalmers University of Technology, Gothenburg, Sweden
| | - Ga-Young Suh
- Department of Biomedical Engineering, California State University, Long Beach, California.,Division of Vascular Surgery, Stanford University, Stanford, California
| | - Torbjörn Lundh
- Mathematical Sciences, Chalmers University of Technology and University of Gothenburg, Gothenburg, Sweden
| | - Michael D Dake
- Department of Surgery, University of Arizona, Tucson, Arizona
| | - Jason T Lee
- Division of Vascular Surgery, Stanford University, Stanford, California
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23
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Tortuosity of the Descending Thoracic Aorta in Patients with Aneurysm and Type B Dissection. World J Surg 2020; 44:1323-1330. [PMID: 31873803 DOI: 10.1007/s00268-019-05328-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
OBJECTIVE Tortuosity in the descending thoracic aorta (DTA) comes with aging and increases the risk of endoleaks after TEVAR. With this report, we would like to define and classify tortuosity in the DTA of patients with thoracic aortic disease. METHODS Retrospective case-control study of two hundred seven patients, comparing sixty-nine controls without aortic disease (CG), to sixty-nine patients with descending thoracic aortic aneurysm (AG) and sixty-nine patients with type B aortic dissection (DG). 3Mensio Vascular software was used to analyze CTA scans and collect the following measurements; tortuosity index, curvature ratio and the maximum tortuosity of the DTA. The DTA was divided into four equal zones. The maximum tortuosity was divided into three groups: low (<30°), moderate (30°-60°) and high tortuosity (>60°). RESULTS Compared to the CG, tortuosity was more pronounced in the DG, and even more in the AG, evidenced by the tortuosity index (1.11 vs. 1.20 vs. 1.31; p < 0.001), curvature ratio (1.00 vs. 1.01 vs. 1.03; p < 0.001), maximum tortuosity in degrees (28.17 vs. 33.29 vs. 43.83; p < 0.001) and group of tortuosity (p < 0.001). The maximum tortuosity was further distal for the DG and AG, evidenced by the zone of maximum tortuosity (4A vs. 4B vs. 4B; p < 0.001). CONCLUSION This study shows that tortuosity in the DTA is more prominent in diseased aortas, especially in aneurysmal disease. This phenomenon needs to be taken into account during planning of TEVAR to prevent stent graft-related complications and to obtain positive long-term outcome.
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Hardikar A, Harle R, Marwick TH. Aortic Thickness: A Forgotten Paradigm in Risk Stratification of Aortic Disease. AORTA : OFFICIAL JOURNAL OF THE AORTIC INSTITUTE AT YALE-NEW HAVEN HOSPITAL 2020; 8:132-140. [PMID: 33368098 PMCID: PMC7758112 DOI: 10.1055/s-0040-1715609] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
BACKGROUND This study aimed at risk-stratifying aortic dilatation using aortic wall thickness (AWT) and comparing methods of AWT assessment. METHODS Demographic, epidemiological, and perioperative data on 72 consecutive aortic surgeries (age = 62 years[standard deviation (SD) = 12] years) performed by a single surgeon were collected from hospital database. Aortic thickness was measured on computed tomography scans, as well as intraoperatively in four quadrants, at the level of aortic sinuses, as well as midascending aorta, using calipers. Aortic wall stress was calculated using standard mathematical formulae. RESULTS The ascending aorta was 48.2 (SD = 8) mm and the mean thickness at ascending aorta level was 1.9 (SD = 0.3) mm. There was congruence between imaging and intraoperative measurements of thickness, as well as between the radiologist and surgeon. Preoperatively, 16 patients had multiple imaging studies showing an average rate of growth of 1.2 mm per year without significant difference in thickness. The wider the aorta, the thinner was the lateral or convex wall. Aortic stenosis (p = 0.01), lateral to medial wall thickness ratio (p = 0.04), and history of hypertension (p = 0.00), all had protective effect on aortic root stress. The ascending aortic stress was directly affected by age (p = 0.03) and inversely related to lateral to medial wall thickness ratio (p = 0.03). CONCLUSION Aortic thickness can be measured preoperatively and easily confirmed intraoperatively. Risk stratification based on both aortic thickness and diameter (stress calculations) would better predict acute aortic events in dilated aortas and define aortic resection criteria more objectively.
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Affiliation(s)
- Ashutosh Hardikar
- Menzies Institute for Medical Research, University of Tasmania, Australia.,Department of Cardiothoracic Surgery, Royal Hobart Hospital, Hobart, Australia
| | - Robin Harle
- Department of Radiology, Royal Hobart Hospital, Hobart, Australia
| | - Thomas H Marwick
- Menzies Institute for Medical Research, University of Tasmania, Australia.,Baker Heart and Diabetes Institute, Melbourne, Australia
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Kuang J, Yang J, Wang Q, Yu C, Li Y, Fan R. A preoperative mortality risk assessment model for Stanford type A acute aortic dissection. BMC Cardiovasc Disord 2020; 20:508. [PMID: 33272195 PMCID: PMC7712615 DOI: 10.1186/s12872-020-01802-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Accepted: 11/26/2020] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Acute aortic dissection type A is a life-threatening disease required emergency surgery during acute phase. Different clinical manifestations, laboratory tests, and imaging features of patients with acute aortic dissection type A are the risk factors of preoperative mortality. This study aims to establish a simple and effective preoperative mortality risk assessment model for patients with acute aortic dissection type A. METHODS A total of 673 Chinese patients with acute aortic dissection type A who were admitted to our hospital were retrospectively included. All patients were unable to receive surgically treatment within 3 days from the onset of disease. The patients included were divided into the survivor and deceased groups, and the endpoint event was preoperative death. Multivariable analysis was used to investigate predictors of preoperative mortality and to develop a prediction model. RESULTS Among the 673 patients, 527 patients survived (78.31%) and 146 patients died (21.69%). The developmental dataset had 505 patients, calibration by Hosmer Lemeshow was significant (χ2 = 3.260, df = 8, P = 0.917) and discrimination by area under ROC curve was 0.8448 (95% CI 0.8007-0.8888). The validation dataset had 168 patients, calibration was significant (χ2 = 5.500, df = 8, P = 0.703) and the area under the ROC curve was 0.8086 (95% CI 0.7291-0.8881). The following independent variables increased preoperative mortality: age (OR = 1.008, P = 0.510), abrupt chest pain (OR = 3.534, P < 0.001), lactic in arterial blood gas ≥ 3 mmol/L (OR = 3.636, P < 0.001), inotropic support (OR = 8.615, P < 0.001), electrocardiographic myocardial ischemia (OR = 3.300, P = 0.001), innominate artery involvement (OR = 1.625, P = 0.104), right common carotid artery involvement (OR = 3.487, P = 0.001), superior mesenteric artery involvement (OR = 2.651, P = 0.001), false lumen / true lumen of ascending aorta ≥ 0.75 (OR = 2.221, P = 0.007). Our data suggest that a simple and effective preoperative death risk assessment model has been established. CONCLUSIONS Using a simple and effective risk assessment model can help clinicians quickly identify high-risk patients and make appropriate medical decisions.
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Affiliation(s)
- Juntao Kuang
- Department of Cardiovascular Surgery, Guangdong Provincial Cardiovascular Institute, Guangdong Provincial People’s Hospital, Guangdong Academy of Medical Sciences, Guangzhou, 510080 China
- The Second School of Clinical Medicine, Southern Medical University, Guangzhou, 510515 China
| | - Jue Yang
- Department of Cardiovascular Surgery, Guangdong Provincial Cardiovascular Institute, Guangdong Provincial People’s Hospital, Guangdong Academy of Medical Sciences, Guangzhou, 510080 China
| | - Qiuji Wang
- Department of Cardiovascular Surgery, Guangdong Provincial Cardiovascular Institute, Guangdong Provincial People’s Hospital, Guangdong Academy of Medical Sciences, Guangzhou, 510080 China
- The Second School of Clinical Medicine, Southern Medical University, Guangzhou, 510515 China
| | - Changjiang Yu
- Department of Cardiovascular Surgery, Guangdong Provincial Cardiovascular Institute, Guangdong Provincial People’s Hospital, Guangdong Academy of Medical Sciences, Guangzhou, 510080 China
| | - Ying Li
- Department of Cardiovascular Surgery, Guangdong Provincial Cardiovascular Institute, Guangdong Provincial People’s Hospital, Guangdong Academy of Medical Sciences, Guangzhou, 510080 China
- Department of Cardiovascular Surgery, Guangdong Provincial People’s Hospital, School of Medicine, South China University of Technology, Guangzhou, 510030 China
| | - Ruixin Fan
- Department of Cardiovascular Surgery, Guangdong Provincial Cardiovascular Institute, Guangdong Provincial People’s Hospital, Guangdong Academy of Medical Sciences, Guangzhou, 510080 China
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Dhara SS, Hermsen M, Khabaz K, Abbott E, Babrowski TA, Milner R, Lee CJ, Pocivavsek L. Gaussian Surface Curvature Mapping Indicating High Risk Type B Thoracic Aortic Dissections. Ann Vasc Surg 2020; 70:171-180. [PMID: 32866573 DOI: 10.1016/j.avsg.2020.08.096] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2020] [Revised: 07/31/2020] [Accepted: 08/23/2020] [Indexed: 11/24/2022]
Abstract
BACKGROUND Identifying fragile aortas that are more likely to lead to adverse clinical outcomes would provide surgeons with a better sense of how to balance the risks of surgical versus medical management in patients with type B dissections. We examine the progression of a type B dissection into a type A dissection in a patient and analyze changes in the Gaussian surface curvature distribution, as well as the response of the stress distribution at the lesser curve in response to pressurization. We hypothesize that examining the Gaussian curvature will provide us with a link between aortic surface geometry and the stress distribution, which is crucial to understanding the process driving aortic dissection. METHODS Computed tomography scans of a patient before and after the type A dissection are obtained. These are segmented in Simpleware ScanIP. Centerline curvatures are calculated on segmented models in ScanIP. Models are then pressurized in the finite element analysis software Abaqus. The Gaussian curvature is calculated by exporting segmentations into the computational program Matlab and applying a modified previously published algorithm. RESULTS The centerlines generated in ScanIP fail to capture the change in the acuity of the lesser curve before and after the type A dissection. Instead, Gaussian curvature analysis shows that the curvature distribution before the type A dissection is much wider compared with the distribution after the type A dissection. In addition, analyzing the stress distribution in response to pressurization reveals that before the type A dissection there is a large divergence in the principal stress vectors at the lesser curve but this transitions to a more uniform hoop stress after the type A dissection. CONCLUSIONS Our analysis demonstrates that Gaussian surface curvature analysis captures changes in aortic geometry that are otherwise silent in centerline curvature analysis. Here, we show that as the aorta develops a type A dissection it is able to more smoothly handle the hoop stress at the lesser curve compared with the stress focusing seen in the before type A geometry. We propose that the geometric focusing before type A creates a higher energy stress state, which is relaxed on retrograde dissection. Thus, Gaussian curvature analysis may provide a window to capture underlying geometric instability in type B dissections.
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Affiliation(s)
- Sanjeev S Dhara
- The University of Chicago Pritzker School of Medicine, Chicago, IL
| | - Michael Hermsen
- The University of Chicago Pritzker School of Medicine, Chicago, IL
| | | | | | - Trissa A Babrowski
- Department of Surgery, Section of Vascular Surgery and Endovascular Therapy, The University of Chicago Medicine, Chicago, IL
| | - Ross Milner
- Department of Surgery, Section of Vascular Surgery and Endovascular Therapy, The University of Chicago Medicine, Chicago, IL
| | - Cheong J Lee
- Department of Surgery, Section of Vascular Surgery, NorthShore Medicine, Skokie, IL
| | - Luka Pocivavsek
- Department of Surgery, Section of Vascular Surgery and Endovascular Therapy, The University of Chicago Medicine, Chicago, IL.
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27
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Sundström E, Jonnagiri R, Gutmark-Little I, Gutmark E, Critser P, Taylor MD, Tretter JT. Hemodynamics and tissue biomechanics of the thoracic aorta with a trileaflet aortic valve at different phases of valve opening. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2020; 36:e3345. [PMID: 32359198 DOI: 10.1002/cnm.3345] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 02/17/2020] [Accepted: 04/19/2020] [Indexed: 06/11/2023]
Abstract
In a normal cardiac cycle, the trileaflet aortic valve opening is progressive, which correlates with the phasic blood flow. Therefore, we aimed to determine the impact of including an anatomically accurate reconstructed trileaflet aortic valve within a fluid-structure interaction (FSI) simulation model and determine the cyclical hemodynamic forces imposed on the thoracic aortic walls from aortic valve opening to closure. A pediatric patient with a normal trileaflet valve was recruited. Using the Cardiac Magnetic Resonance Data (CMR), a 3D model of the aortic valve and thoracic aorta was reconstructed. FSI simulations were employed to assess the tissue stress during a cardiac cycle as the result of changes in the valve opening. The blood flow was simulated as a mixture of blood plasma and red blood cells to account for non-Newtonian effects. The computation was validated with phase-contrast CMR. Windkessel boundary conditions were employed to ensure physiological pressures during the cardiac cycle. The leaflets' dynamic motion during the cardiac cycle was defined with an analytic grid velocity function. At the beginning of the valve opening a thin jet is developing. From mid-open towards full opening the stress level increases where the jet impinges the convex wall. At peak systole two counter-rotating Dean-like vortex cores manifest in the ascending aorta, which correlates with increased integrated mean stress levels. An accurate trileaflet aortic valve is needed for capturing of both primary and secondary flow features that impact the forces on the thoracic aorta wall. Omitting the aortic valve underestimates the biomechanical response.
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Affiliation(s)
- Elias Sundström
- Department of Otolaryngology-Head and Neck Surgery, University of Cincinnati, Cincinnati, Ohio, USA
| | - Raghuvir Jonnagiri
- Department of Aerospace Engineering and Engineering Mechanics, University of Cincinnati, Cincinnati, Ohio, USA
| | - Iris Gutmark-Little
- Division of Endocrine, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Ephraim Gutmark
- Department of Otolaryngology-Head and Neck Surgery, University of Cincinnati, Cincinnati, Ohio, USA
- Department of Aerospace Engineering and Engineering Mechanics, University of Cincinnati, Cincinnati, Ohio, USA
| | - Paul Critser
- Heart Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Michael D Taylor
- Heart Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
- Department of Pediatrics, University of Cincinnati, Cincinnati, Ohio, USA
| | - Justin T Tretter
- Heart Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
- Department of Pediatrics, University of Cincinnati, Cincinnati, Ohio, USA
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28
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Maiti S, Thunes JR, Fortunato RN, Gleason TG, Vorp DA. Computational modeling of the strength of the ascending thoracic aortic media tissue under physiologic biaxial loading conditions. J Biomech 2020; 108:109884. [PMID: 32635998 DOI: 10.1016/j.jbiomech.2020.109884] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Revised: 05/10/2020] [Accepted: 06/06/2020] [Indexed: 12/23/2022]
Abstract
Type A Aortic Dissection (TAAD) is a life-threatening condition involving delamination of ascending aortic media layers. While current clinical guidelines recommend surgical intervention for aneurysm diameter > 5.5 cm, high incidence of TAAD in patients below this diameter threshold indicates the pressing need for improved evidence-based risk prediction metrics. Construction of such metrics will require the knowledge of the biomechanical failure properties of the aortic wall tissue under biaxial loading conditions. We utilized a fiber-level finite element based structural model of the aortic tissue to quantify the relationship between aortic tissue strength and physiologically relevant biaxial stress state for nonaneurysmal and aneurysmal patient cohorts with tricuspid aortic valve phenotype. We found that the model predicted strength of the aortic tissue under physiologic biaxial loading conditions depends on the stress biaxiality ratio, defined by the ratio of the longitudinal and circumferential components of the tissue stress. We determined that predicted biaxial tissue strength is statistically similar to its uniaxial circumferential strength below biaxiality ratios of 0.68 and 0.69 for nonaneurysmal and aneurysmal cohorts, respectively. Beyond this biaxiality ratio, predicted biaxial strength for both cohorts reduced drastically to a magnitude statistically similar to its longitudinal strength. We identified fiber-level failure mechanisms operative under biaxial stress state governing aforementioned tissue failure behavior. These findings are an important first step towards the development of mechanism-based TAAD risk assessment metrics for early identification of high-risk patients.
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Affiliation(s)
- Spandan Maiti
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States; Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, PA, United States; Mechanical Engineering and Materials Science, University of Pittsburgh, Pittsburgh, PA, United States.
| | | | - Ronald N Fortunato
- Mechanical Engineering and Materials Science, University of Pittsburgh, Pittsburgh, PA, United States
| | - Thomas G Gleason
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States; Cardiothoracic Surgery, University of Pittsburgh, Pittsburgh, PA, United States; Surgery, University of Pittsburgh, Pittsburgh, PA, United States; Center for Vascular Remodeling and Regeneration, University of Pittsburgh, Pittsburgh, PA, United States; Center for Vascular Remodeling and Regeneration, University of Pittsburgh, Pittsburgh, PA, United States
| | - David A Vorp
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States; Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, PA, United States; Cardiothoracic Surgery, University of Pittsburgh, Pittsburgh, PA, United States; Surgery, University of Pittsburgh, Pittsburgh, PA, United States; Center for Vascular Remodeling and Regeneration, University of Pittsburgh, Pittsburgh, PA, United States; McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, United States; Clinical and Translational Sciences Institute, University of Pittsburgh, Pittsburgh, PA, United States
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29
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Bersi MR, Acosta Santamaría VA, Marback K, Di Achille P, Phillips EH, Goergen CJ, Humphrey JD, Avril S. Multimodality Imaging-Based Characterization of Regional Material Properties in a Murine Model of Aortic Dissection. Sci Rep 2020; 10:9244. [PMID: 32514185 PMCID: PMC7280301 DOI: 10.1038/s41598-020-65624-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Accepted: 05/04/2020] [Indexed: 01/21/2023] Open
Abstract
Chronic infusion of angiotensin-II in atheroprone (ApoE-/-) mice provides a reproducible model of dissection in the suprarenal abdominal aorta, often with a false lumen and intramural thrombus that thickens the wall. Such lesions exhibit complex morphologies, with different regions characterized by localized changes in wall composition, microstructure, and properties. We sought to quantify the multiaxial mechanical properties of murine dissecting aneurysm samples by combining in vitro extension-distension data with full-field multimodality measurements of wall strain and thickness to inform an inverse material characterization using the virtual fields method. A key advance is the use of a digital volume correlation approach that allows for characterization of properties not only along and around the lesion, but also across its wall. Specifically, deformations are measured at the adventitial surface by tracking motions of a speckle pattern using a custom panoramic digital image correlation technique while deformations throughout the wall and thrombus are inferred from optical coherence tomography. These measurements are registered and combined in 3D to reconstruct the reference geometry and compute the 3D finite strain fields in response to pressurization. Results reveal dramatic regional variations in material stiffness and strain energy, which reflect local changes in constituent area fractions obtained from histology but emphasize the complexity of lesion morphology and damage within the dissected wall. This is the first point-wise biomechanical characterization of such complex, heterogeneous arterial segments. Because matrix remodeling is critical to the formation and growth of these lesions, we submit that quantification of regional material properties will increase the understanding of pathological mechanical mechanisms underlying aortic dissection.
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Affiliation(s)
- Matthew R Bersi
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, USA
| | | | - Karl Marback
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
| | - Paolo Di Achille
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
| | - Evan H Phillips
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA
| | - Craig J Goergen
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA
| | - Jay D Humphrey
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
- Vascular Biology and Therapeutics Program, Yale School of Medicine, New Haven, CT, USA
| | - Stéphane Avril
- Mines Saint-Etienne, University of Lyon, University Jean Monnet, INSERM, Saint-Etienne, France.
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30
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Cebull HL, Rayz VL, Goergen CJ. Recent Advances in Biomechanical Characterization of Thoracic Aortic Aneurysms. Front Cardiovasc Med 2020; 7:75. [PMID: 32478096 PMCID: PMC7235347 DOI: 10.3389/fcvm.2020.00075] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Accepted: 04/14/2020] [Indexed: 12/18/2022] Open
Abstract
Thoracic aortic aneurysm (TAA) is a focal enlargement of the thoracic aorta, but the etiology of this disease is not fully understood. Previous work suggests that various genetic syndromes, congenital defects such as bicuspid aortic valve, hypertension, and age are associated with TAA formation. Though occurrence of TAAs is rare, they can be life-threatening when dissection or rupture occurs. Prevention of these adverse events often requires surgical intervention through full aortic root replacement or implantation of endovascular stent grafts. Currently, aneurysm diameters and expansion rates are used to determine if intervention is warranted. Unfortunately, this approach oversimplifies the complex aortopathy. Improving treatment of TAAs will likely require an increased understanding of the biological and biomechanical factors contributing to the disease. Past studies have substantially contributed to our knowledge of TAAs using various ex vivo, in vivo, and computational methods to biomechanically characterize the thoracic aorta. However, any singular approach typically focuses on only material properties of the aortic wall, intra-aneurysmal hemodynamics, or in vivo vessel dynamics, neglecting combinatorial factors that influence aneurysm development and progression. In this review, we briefly summarize the current understanding of TAA causes, treatment, and progression, before discussing recent advances in biomechanical studies of TAAs and possible future directions. We identify the need for comprehensive approaches that combine multiple characterization methods to study the mechanisms contributing to focal weakening and rupture. We hope this summary and analysis will inspire future studies leading to improved prediction of thoracic aneurysm progression and rupture, improving patient diagnoses and outcomes.
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Affiliation(s)
- Hannah L Cebull
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, United States
| | - Vitaliy L Rayz
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, United States
| | - Craig J Goergen
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, United States.,Purdue Center for Cancer Research, Purdue University, West Lafayette, IN, United States
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31
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Cao L, Lu W, Ge Y, Wang X, He Y, Sun G, Liu J, Liu X, Jia X, Xiong J, Ma X, Zhang H, Wang L, Guo W. Altered aortic arch geometry in patients with type B aortic dissection. Eur J Cardiothorac Surg 2020; 58:714-721. [PMID: 32303067 DOI: 10.1093/ejcts/ezaa102] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 02/20/2020] [Accepted: 02/21/2020] [Indexed: 01/22/2023] Open
Abstract
Abstract
OBJECTIVES
This study aims to evaluate differences in proximal aorta geometry and identify specific anatomical predictors of type B aortic dissection (TBAD).
METHODS
We evaluated computed tomographic angiograms of controls (n = 185) and patients with acute TBAD (n = 173). Using propensity score matching, we created 2 groups of 127 patients. 3mensio Vascular software was used to analyse the computed tomographic angiograms and measure the diameter, length, tortuosity index and angulation of the proximal aorta (divided into ascending aorta and aortic arch). Tortuosity index was calculated by dividing the centre lumen line length of the aortic segment by its shortest length. Angulation was measured by the centre lumen line ‘tangent line angle’. Two independent multivariable models identified significant anatomical associations regarding the tortuosity and angulation geometry.
RESULTS
Aortic diameter and ascending aorta and aortic arch lengths in TBAD increased significantly. The aortic arch tortuosity was significantly higher in the TBAD group (P < 0.001), with no difference regarding the ascending aorta (P = 0.11). Ascending aorta and aortic arch angulation were significantly higher in the TBAD group (P = 0.01, P < 0.001, respectively). Multivariable analyses showed that increased aortic arch tortuosity and angulation were significant predictors of the development of TBAD [odds ratio (OR) 1.91, 95% confidence interval (CI) 1.40–2.59; P < 0.001 and OR 1.08, 95% CI 1.04–1.12; P < 0.001], respectively.
CONCLUSIONS
In addition to proximal aorta dilation and elongation, we identified increased aortic arch tortuosity and angulation as possible specific predictors of TBAD.
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Affiliation(s)
- Long Cao
- Department of Vascular and Endovascular Surgery, Chinese PLA General Hospital, Beijing, China
- Department of General Surgery, Chinese PLA No. 983 Hospital, Tianjin, China
| | - Weihang Lu
- Department of General Surgery, The Sixth Medical Center of Chinese PLA General Hospital, Beijing, China
| | - Yangyang Ge
- Department of Vascular and Endovascular Surgery, Chinese PLA General Hospital, Beijing, China
| | - Xinhao Wang
- Department of Vascular and Endovascular Surgery, Chinese PLA General Hospital, Beijing, China
| | - Yuan He
- Department of Vascular and Endovascular Surgery, Chinese PLA General Hospital, Beijing, China
| | - Guoyi Sun
- Department of Vascular and Endovascular Surgery, Chinese PLA General Hospital, Beijing, China
| | - Jie Liu
- Department of Vascular and Endovascular Surgery, Chinese PLA General Hospital, Beijing, China
| | - Xiaoping Liu
- Department of Vascular and Endovascular Surgery, Chinese PLA General Hospital, Beijing, China
| | - Xin Jia
- Department of Vascular and Endovascular Surgery, Chinese PLA General Hospital, Beijing, China
| | - Jiang Xiong
- Department of Vascular and Endovascular Surgery, Chinese PLA General Hospital, Beijing, China
| | - Xiaohui Ma
- Department of Vascular and Endovascular Surgery, Chinese PLA General Hospital, Beijing, China
| | - Hongpeng Zhang
- Department of Vascular and Endovascular Surgery, Chinese PLA General Hospital, Beijing, China
| | - Lijun Wang
- Department of Vascular and Endovascular Surgery, Chinese PLA General Hospital, Beijing, China
| | - Wei Guo
- Department of Vascular and Endovascular Surgery, Chinese PLA General Hospital, Beijing, China
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Marrocco-Trischitta MM, Alaidroos M, Romarowski RM, Secchi F, Righini P, Glauber M, Nano G. Geometric Pattern of Proximal Landing Zones for Thoracic Endovascular Aortic Repair in the Bovine Arch Variant. Eur J Vasc Endovasc Surg 2019; 59:808-816. [PMID: 31889656 DOI: 10.1016/j.ejvs.2019.11.019] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Revised: 10/14/2019] [Accepted: 11/12/2019] [Indexed: 01/09/2023]
Abstract
OBJECTIVE The aim was to investigate whether the "bovine" aortic arch (i.e. arch variant with a common origin of the innominate and left carotid artery (CILCA)) is associated with a consistent geometric configuration of proximal landing zones for thoracic endovascular aortic repair (TEVAR). METHODS Anonymised thoracic computed tomography (CT) scans of healthy aortas were reviewed to retrieve 100 cases of CILCA. Suitable cases were stratified according to type 1 and 2 CILCA, and also based on type of arch (I, II, and III). Further processing allowed calculation of angulation and tortuosity of the proximal landing zones. Centre lumen line lengths of each proximal landing zone were measured in a view perpendicular to the centre line. All geometric features were compared with those measured in healthy patients with a standard arch configuration (n = 60). Two senior authors independently evaluated the CT scans, and intra- and interobserver repeatability were assessed. RESULTS The 100 selected patients (63% male) were 71.4 ± 7.7 years old. Type 1 CILCA (62/100) was more prevalent than type 2 CILCA (38/100), and the two groups were comparable in age (p = .11). Zone 3 presented a severe angulation (i.e. > 60°), which was greater than in Zone 2 (p < .001), and a consistently greater tortuosity than Zone 2 (p = .003). This pattern did not differ between type 1 and type 2 CILCA. A greater tortuosity was also observed in Zone 0, which was related to increased elongation of the ascending aorta (i.e. Zone 0), than the standard configuration. The CILCA had an overall greater elongation, and Zone 2 also was specifically longer. When stratifying by type of arch, reversely from Type III to Type I, the CILCA presented a gradual flattening of its transverse tract, which entailed a consistent progressive elongation (p = .03) and kinking of the ascending aorta, with a significant increase of Zone 0 angulation to even a severe degree (p = .001). Also, from Type III to Type I, Zone 2 presented a progressively shorter length (p = .004), which was associated with increased tortuosity (p < .05). Mean intra- and interobserver differences for angulation measurements were 1.4° ± 6.8° (p = .17) and 2.0° ± 10.1° (p = .19), respectively. CONCLUSION CILCA presents a consistent and peculiar geometric pattern compared with standard arch configuration, which provides relevant information for TEVAR planning, and may have prognostic implications.
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Affiliation(s)
- Massimiliano M Marrocco-Trischitta
- Clinical Research Unit, IRCCS - Policlinico San Donato, Milan, Italy; Vascular Surgery Unit, IRCCS - Policlinico San Donato, Milan, Italy.
| | - Moad Alaidroos
- Clinical Research Unit, IRCCS - Policlinico San Donato, Milan, Italy; Vascular Surgery Unit, Policlinico San Marco, Zingonia, Italy
| | - Rodrigo M Romarowski
- 3D and Computer Simulation Laboratory, IRCCS - Policlinico San Donato, Milan, Italy
| | - Francesco Secchi
- Division of Radiology, IRCCS - Policlinico San Donato, Milan, Italy; Department of "Scienze Biomediche per la Salute", University of Milan, Italy
| | - Paolo Righini
- Vascular Surgery Unit, IRCCS - Policlinico San Donato, Milan, Italy
| | - Mattia Glauber
- Minimally Invasive Cardiac Surgery Unit, Istituto Clinico Sant'Ambrogio, Milan, Italy
| | - Giovanni Nano
- Vascular Surgery Unit, IRCCS - Policlinico San Donato, Milan, Italy; Department of "Scienze Biomediche per la Salute", University of Milan, Italy
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33
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Korenczuk CE, Dhume RY, Liao KK, Barocas VH. Ex Vivo Mechanical Tests and Multiscale Computational Modeling Highlight the Importance of Intramural Shear Stress in Ascending Thoracic Aortic Aneurysms. J Biomech Eng 2019; 141:121010. [PMID: 31633165 PMCID: PMC7104749 DOI: 10.1115/1.4045270] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 10/17/2019] [Indexed: 11/08/2022]
Abstract
Ascending thoracic aortic aneurysms (ATAAs) are anatomically complex in terms of architecture and geometry, and both complexities contribute to unpredictability of ATAA dissection and rupture in vivo. The goal of this work was to examine the mechanism of ATAA failure using a combination of detailed mechanical tests on human tissue and a multiscale computational model. We used (1) multiple, geometrically diverse, mechanical tests to characterize tissue properties; (2) a multiscale computational model to translate those results into a broadly usable form; and (3) a model-based computer simulation of the response of an ATAA to the stresses generated by the blood pressure. Mechanical tests were performed in uniaxial extension, biaxial extension, shear lap, and peel geometries. ATAA tissue was strongest in circumferential extension and weakest in shear, presumably because of the collagen and elastin in the arterial lamellae. A multiscale, fiber-based model using different fiber properties for collagen, elastin, and interlamellar connections was specified to match all of the experimental data with one parameter set. Finally, this model was used to simulate ATAA inflation using a realistic geometry. The predicted tissue failure occurred in regions of high stress, as expected; initial failure events involved almost entirely interlamellar connections, consistent with arterial dissection-the elastic lamellae remain intact, but the connections between them fail. The failure of the interlamellar connections, paired with the weakness of the tissue under shear loading, is suggestive that shear stress within the tissue may contribute to ATAA dissection.
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Affiliation(s)
- Christopher E. Korenczuk
- Department of Biomedical Engineering, University of Minnesota,7-105 Nils Hasselmo Hall, 312 Church Street SE, Minneapolis, MN 55455e-mail:
| | - Rohit Y. Dhume
- Department of Mechanical Engineering, University of Minnesota,7-105 Nils Hasselmo Hall, 312 Church Street SE, Minneapolis, MN 55455e-mail:
| | - Kenneth K. Liao
- Department of Surgery, University of Minnesota,420 Delaware Street SE, MMC 207, Minneapolis, MN 55455e-mail:
| | - Victor H. Barocas
- Department of Biomedical Engineering, University of Minnesota,7-105 Nils Hasselmo Hall, 312 Church Street SE, Minneapolis, MN 55455e-mail:
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Sundström E, Jonnagiri R, Gutmark-Little I, Gutmark E, Critser P, Taylor MD, Tretter JT. Effects of Normal Variation in the Rotational Position of the Aortic Root on Hemodynamics and Tissue Biomechanics of the Thoracic Aorta. Cardiovasc Eng Technol 2019; 11:47-58. [PMID: 31701357 DOI: 10.1007/s13239-019-00441-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Accepted: 10/30/2019] [Indexed: 01/04/2023]
Abstract
PURPOSE Variation in the rotational position of the aortic root relative to the left ventricle is present in normal trileaflet aortic valves. Its impact on the resulting fluid mechanics of blood flow in the thoracic aorta and structural mechanics in the aortic wall are unknown. We aimed to determine the regional hemodynamic and biomechanical differences in different rotational positions of the normal aortic root (clockwise, central, and counterclockwise positions). METHOD Cardiac magnetic resonance imaging (CMR) data was acquired from a normal pediatric patient. These were used for reconstruction of the aortic valve and thoracic aorta 3D model. Fluid-structure interaction (FSI) simulations were employed to study the influence of the root rotation with a central position as compared to observed extreme variations. Patient-specific phase-encoding CMR data were used to assess the validity of computed blood flow. The 3D FSI model was coupled with Windkessel boundary conditions that were tuned for physiological pressures. A grid velocity function was adopted for the valve motion during the systolic period. RESULTS The largest wall shear stress level is detected in the clockwise positioned aortic root at the sinutubular junction. Two counter-rotating vortex cores are formed within the aortic root of both the central and extreme root configurations, however, in the clockwise root the vortex system becomes more symmetric. This also coincides with more entrainment of the valve jet and more turbulence production along the shear layer. CONCLUSION A clockwise rotational position of the aortic root imparts an increased wall shear stress at the sinutubular junction and proximal ascending aorta in comparison to other root rotation positions. This may pose increased risk for dilation of the sinutubular junction and ascending aorta in the patient with a clockwise positioned aortic root compared to other normal positional configurations.
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Affiliation(s)
- Elias Sundström
- Department of Otolaryngology-Head and Neck Surgery, University of Cincinnati, Cincinnati, OH, 45267, USA.
| | - Raghuvir Jonnagiri
- Department of Aerospace Engineering and Engineering Mechanics, University of Cincinnati, Cincinnati, OH, 45221, USA
| | - Iris Gutmark-Little
- Division of Endocrine, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, USA
| | - Ephraim Gutmark
- Department of Otolaryngology-Head and Neck Surgery, University of Cincinnati, Cincinnati, OH, 45267, USA.,Department of Aerospace Engineering and Engineering Mechanics, University of Cincinnati, Cincinnati, OH, 45221, USA
| | - Paul Critser
- Heart Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, USA
| | - Michael D Taylor
- Heart Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, USA.,Department of Pediatrics, University of Cincinnati, Cincinnati, OH, 45267, USA
| | - Justin T Tretter
- Heart Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, USA.,Department of Pediatrics, University of Cincinnati, Cincinnati, OH, 45267, USA
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Sherifova S, Holzapfel GA. Biomechanics of aortic wall failure with a focus on dissection and aneurysm: A review. Acta Biomater 2019; 99:1-17. [PMID: 31419563 PMCID: PMC6851434 DOI: 10.1016/j.actbio.2019.08.017] [Citation(s) in RCA: 96] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Revised: 08/05/2019] [Accepted: 08/08/2019] [Indexed: 12/12/2022]
Abstract
Aortic dissections and aortic aneurysms are fatal events characterized by structural changes to the aortic wall. The maximum diameter criterion, typically used for aneurysm rupture risk estimations, has been challenged by more sophisticated biomechanically motivated models in the past. Although these models are very helpful for the clinicians in decision-making, they do not attempt to capture material failure. Following a short overview of the microstructure of the aorta, we analyze the failure mechanisms involved in the dissection and rupture by considering also traumatic rupture. We continue with a literature review of experimental studies relevant to quantify tissue strength. More specifically, we summarize more extensively uniaxial tensile, bulge inflation and peeling tests, and we also specify trouser, direct tension and in-plane shear tests. Finally we analyze biomechanically motivated models to predict rupture risk. Based on the findings of the reviewed studies and the rather large variations in tissue strength, we propose that an appropriate material failure criterion for aortic tissues should also reflect the microstructure in order to be effective. STATEMENT OF SIGNIFICANCE: Aortic dissections and aortic aneurysms are fatal events characterized by structural changes to the aortic wall. Despite the advances in medical, biomedical and biomechanical research, the mortality rates of aneurysms and dissections remain high. The present review article summarizes experimental studies that quantify the aortic wall strength and it discusses biomechanically motivated models to predict rupture risk. We identified contradictory observations and a large variation within and between data sets, which may be due to biological variations, different sample sizes, differences in experimental protocols, etc. Based on the findings of the reviewed literature and the rather large variations in tissue strength, it is proposed that an appropriate criterion for aortic failure should also reflect the microstructure.
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Affiliation(s)
- Selda Sherifova
- Institute of Biomechanics, Graz University of Technology, Stremayrgasse 16/2, 8010 Graz, Austria
| | - Gerhard A Holzapfel
- Institute of Biomechanics, Graz University of Technology, Stremayrgasse 16/2, 8010 Graz, Austria; Department of Structural Engineering, Norwegian Institute of Science and Technology (NTNU), 7491 Trondheim, Norway.
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Guo B, Dong Z, Pirola S, Liu Y, Menichini C, Xu XY, Guo D, Fu W. Dissection Level Within Aortic Wall Layers is Associated with Propagation of Type B Aortic Dissection: A Swine Model Study. Eur J Vasc Endovasc Surg 2019; 58:415-425. [PMID: 31337584 DOI: 10.1016/j.ejvs.2019.02.026] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Accepted: 02/22/2019] [Indexed: 01/16/2023]
Abstract
OBJECTIVE Haemodynamic and geometric factors play pivotal roles in the propagation of acute type B aortic dissection (TBAD). The aim of this study was to evaluate the association between dissection level within all aortic layers and the propagation of acute TBAD in porcine aorta. METHODS In twelve pigs, two models of TBAD were created. In model A (n = 6), the aortic wall tear was superficial and close to the intima (thin intimal flap), whereas in model B (n = 6) it was deep and close to the adventitia (thick intimal flap). Dissection propagation was evaluated using angiography or computed tomography scans, and the haemodynamic measurements were acquired using Doppler wires. Most pigs were followed up at 1, 3, 6, 12, 18, and up to 24 months; four animals were euthanised at three and six months, respectively (two from each group). RESULTS Both models were successfully created. No statistical difference was observed for the median antegrade propagation distance intra-operatively between the two models (p = .092). At 24 months, the longitudinal propagation distance was significantly greater in model B than in model A (p = .016). No statistical difference in retrograde propagation was noted (p = .691). Over time, aortic wall dissection progressed most notably over the first three months in model A, whereas it continued over the first 12 months in model B. Flow velocity was significantly greater in the true lumen than in false lumen at the level of the primary tear (p = .001) and in the middle of the dissection (p = .004). The histopathological images at three and six months demonstrated the fibres were stretched linearly at the outside wall of false lumen in both models, while the depth of intimal tears developed to be superficial and similar at the distal dissection. CONCLUSION In this swine model of TBAD, a deeper intimal tear resulted in greater dissection propagation.
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Affiliation(s)
- Baolei Guo
- Department of Vascular Surgery, Zhongshan Hospital Fudan University, Shanghai, China
| | - Zhihui Dong
- Department of Vascular Surgery, Zhongshan Hospital Fudan University, Shanghai, China
| | - Selene Pirola
- Department of Chemical Engineering, Imperial College London, South Kensington Campus, London, UK
| | - Yifan Liu
- Department of Vascular Surgery, Zhongshan Hospital Fudan University, Shanghai, China
| | - Claudia Menichini
- Department of Chemical Engineering, Imperial College London, South Kensington Campus, London, UK
| | - Xiao Yun Xu
- Department of Chemical Engineering, Imperial College London, South Kensington Campus, London, UK
| | - Daqiao Guo
- Department of Vascular Surgery, Zhongshan Hospital Fudan University, Shanghai, China.
| | - Weiguo Fu
- Department of Vascular Surgery, Zhongshan Hospital Fudan University, Shanghai, China.
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Aslanidou L, Ferraro M, Lovric G, Bersi MR, Humphrey JD, Segers P, Trachet B, Stergiopulos N. Co-localization of microstructural damage and excessive mechanical strain at aortic branches in angiotensin-II-infused mice. Biomech Model Mechanobiol 2019; 19:81-97. [PMID: 31273562 DOI: 10.1007/s10237-019-01197-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Accepted: 06/26/2019] [Indexed: 02/07/2023]
Abstract
Animal models of aortic aneurysm and dissection can enhance our limited understanding of the etiology of these lethal conditions particularly because early-stage longitudinal data are scant in humans. Yet, the pathogenesis of often-studied mouse models and the potential contribution of aortic biomechanics therein remain elusive. In this work, we combined micro-CT and synchrotron-based imaging with computational biomechanics to estimate in vivo aortic strains in the abdominal aorta of angiotensin-II-infused ApoE-deficient mice, which were compared with mouse-specific aortic microstructural damage inferred from histopathology. Targeted histology showed that the 3D distribution of micro-CT contrast agent that had been injected in vivo co-localized with precursor vascular damage in the aortic wall at 3 days of hypertension, with damage predominantly near the ostia of the celiac and superior mesenteric arteries. Computations similarly revealed higher mechanical strain in branching relative to non-branching regions, thus resulting in a positive correlation between high strain and vascular damage in branching segments that included the celiac, superior mesenteric, and right renal arteries. These results suggest a mechanically driven initiation of damage at these locations, which was supported by 3D synchrotron imaging of load-induced ex vivo delaminations of angiotensin-II-infused suprarenal abdominal aortas. That is, the major intramural delamination plane in the ex vivo tested aortas was also near side branches and specifically around the celiac artery. Our findings thus support the hypothesis of an early mechanically mediated formation of microstructural defects at aortic branching sites that subsequently propagate into a macroscopic medial tear, giving rise to aortic dissection in angiotensin-II-infused mice.
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Affiliation(s)
- Lydia Aslanidou
- Institute of Bioengineering, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.
| | - Mauro Ferraro
- Institute of Bioengineering, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Goran Lovric
- Centre d'Imagerie BioMédicale, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
- Swiss Light Source, Paul Scherrer Institute, Villigen, Switzerland
| | - Matthew R Bersi
- Department of Biomedical Engineering, Yale University, New Haven, USA
- Department of Biomedical Engineering, Vanderbilt University, Nashville, USA
| | - Jay D Humphrey
- Department of Biomedical Engineering, Yale University, New Haven, USA
| | | | - Bram Trachet
- Institute of Bioengineering, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
- bioMMeda, Ghent University, Ghent, Belgium
| | - Nikos Stergiopulos
- Institute of Bioengineering, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
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Cosentino F, Agnese V, Raffa GM, Gentile G, Bellavia D, Zingales M, Pilato M, Pasta S. On the role of material properties in ascending thoracic aortic aneurysms. Comput Biol Med 2019; 109:70-78. [DOI: 10.1016/j.compbiomed.2019.04.022] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 04/20/2019] [Accepted: 04/20/2019] [Indexed: 12/31/2022]
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Krüger T, Sandoval Boburg R, Lescan M, Oikonomou A, Schneider W, Vöhringer L, Lausberg H, Bamberg F, Blumenstock G, Schlensak C. Aortic elongation in aortic aneurysm and dissection: the Tübingen Aortic Pathoanatomy (TAIPAN) project. Eur J Cardiothorac Surg 2019; 54:26-33. [PMID: 29373683 DOI: 10.1093/ejcts/ezx503] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Accepted: 12/21/2017] [Indexed: 01/15/2023] Open
Abstract
OBJECTIVES To study the lengths and diameters of aortic segments in healthy and diseased aortas and to assess the role of aortic elongation in Type A aortic dissection (TAD) prediction. METHODS Ectasia and aneurysm were defined by ascending aorta diameters of 45-54 mm and ≥55 mm, respectively. Computed tomography angiography studies of 256 healthy, 102 ectasia, 38 aneurysm, 17 pre-TAD and 166 TAD aortas were analysed using curved multiplanar reformats. RESULTS The study groups were structurally equal. The diameter of the ascending aorta was 35 mm in the control group and was larger (P < 0.001) in the pre-TAD (43 mm) and TAD (56 mm) groups. The length of the ascending aorta from the aortic annulus to the brachiocephalic trunk was 92 mm in the control group, 113 mm in the ectasia group, 120 mm in the aneurysm group and 111 mm and 118 mm in the pre-TAD and TAD groups (all P < 0.001 compared with the control group). An ascending aorta length of 120 mm was exceeded in 2% of the control group, 31% of the ectasia group, 50% of the aneurysm group, 24% of the pre-TAD group and 48% of the TAD group. The correlation between the diameter and the length of the ascending aorta was r = 0.752; therefore, both parameters must be examined separately. A score considering both parameters identified 23.5% of pre-TAD patients, significantly more than the diameter alone, and 31.4% of ectasia aortas were elongated. CONCLUSIONS Patients with ectatic (45-54 mm diameter) and elongated (≥120 mm) ascending aortas represent a high-risk subpopulation for TAD.
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Affiliation(s)
- Tobias Krüger
- Department of Thoracic and Cardiovascular Surgery, University Medical Center Tübingen, Tübingen, Germany
| | - Rodrigo Sandoval Boburg
- Department of Thoracic and Cardiovascular Surgery, University Medical Center Tübingen, Tübingen, Germany
| | - Mario Lescan
- Department of Thoracic and Cardiovascular Surgery, University Medical Center Tübingen, Tübingen, Germany
| | - Alexandre Oikonomou
- Department of Thoracic and Cardiovascular Surgery, University Medical Center Tübingen, Tübingen, Germany
| | - Wilke Schneider
- Department of Thoracic and Cardiovascular Surgery, University Medical Center Tübingen, Tübingen, Germany
| | - Luise Vöhringer
- Department of Thoracic and Cardiovascular Surgery, University Medical Center Tübingen, Tübingen, Germany
| | - Henning Lausberg
- Department of Thoracic and Cardiovascular Surgery, University Medical Center Tübingen, Tübingen, Germany
| | - Fabian Bamberg
- Department of Diagnostic and Interventional Radiology, University Medical Center Tübingen, Tübingen, Germany
| | - Gunnar Blumenstock
- Institute for Clinical Epidemiology and Applied Biometry, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Christian Schlensak
- Department of Thoracic and Cardiovascular Surgery, University Medical Center Tübingen, Tübingen, Germany
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Cosentino F, Scardulla F, D'Acquisto L, Agnese V, Gentile G, Raffa G, Bellavia D, Pilato M, Pasta S. Computational modeling of bicuspid aortopathy: Towards personalized risk strategies. J Mol Cell Cardiol 2019; 131:122-131. [PMID: 31047985 DOI: 10.1016/j.yjmcc.2019.04.026] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Revised: 04/09/2019] [Accepted: 04/26/2019] [Indexed: 11/18/2022]
Abstract
This paper describes current advances on the application of in-silico for the understanding of bicuspid aortopathy and future perspectives of this technology on routine clinical care. This includes the impact that artificial intelligence can provide to develop computer-based clinical decision support system and that wearable sensors can offer to remotely monitor high-risk bicuspid aortic valve (BAV) patients. First, we discussed the benefit of computational modeling by providing tangible examples of in-silico software products based on computational fluid-dynamic (CFD) and finite-element method (FEM) that are currently transforming the way we diagnose and treat cardiovascular diseases. Then, we presented recent findings on computational hemodynamic and structural mechanics of BAV to highlight the potentiality of patient-specific metrics (not-based on aortic size) to support the clinical-decision making process of BAV-associated aneurysms. Examples of BAV-related personalized healthcare solutions are illustrated.
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Affiliation(s)
- Federica Cosentino
- Promozione della Salute, Materno-Infantile, di Medicina Interna e Specialistica di Eccellenza "G. D'Alessandro", University of Palermo, Piazza delle Cliniche, n.2, 90128 Palermo, Italy; Fondazione Ri.MED, Via Bandiera n.11, 90133 Palermo, Italy
| | - Francesco Scardulla
- Department of Engineering, University of Palermo, Viale delle Scienze Ed.8, 90128 Palermo, Italy
| | - Leonardo D'Acquisto
- Department of Engineering, University of Palermo, Viale delle Scienze Ed.8, 90128 Palermo, Italy
| | - Valentina Agnese
- Department for the Treatment and Study of Cardiothoracic Diseases and Cardiothoracic Transplantation, IRCCS-ISMETT, Via Tricomi n.5, 90127 Palermo, Italy
| | - Giovanni Gentile
- Department for the Treatment and Study of Cardiothoracic Diseases and Cardiothoracic Transplantation, IRCCS-ISMETT, Via Tricomi n.5, 90127 Palermo, Italy
| | - Giuseppe Raffa
- Department for the Treatment and Study of Cardiothoracic Diseases and Cardiothoracic Transplantation, IRCCS-ISMETT, Via Tricomi n.5, 90127 Palermo, Italy
| | - Diego Bellavia
- Department for the Treatment and Study of Cardiothoracic Diseases and Cardiothoracic Transplantation, IRCCS-ISMETT, Via Tricomi n.5, 90127 Palermo, Italy
| | - Michele Pilato
- Department for the Treatment and Study of Cardiothoracic Diseases and Cardiothoracic Transplantation, IRCCS-ISMETT, Via Tricomi n.5, 90127 Palermo, Italy
| | - Salvatore Pasta
- Fondazione Ri.MED, Via Bandiera n.11, 90133 Palermo, Italy; Department for the Treatment and Study of Cardiothoracic Diseases and Cardiothoracic Transplantation, IRCCS-ISMETT, Via Tricomi n.5, 90127 Palermo, Italy.
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Marrocco-Trischitta MM, Rylski B, Schofer F, Secchi F, Piffaretti G, de Beaufort H, Belvroy V, Bismuth J, Czerny M, Trimarchi S. Prevalence of type III arch configuration in patients with type B aortic dissection. Eur J Cardiothorac Surg 2019; 56:1075-1080. [DOI: 10.1093/ejcts/ezz137] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Revised: 03/26/2019] [Accepted: 04/01/2019] [Indexed: 12/23/2022] Open
Abstract
Abstract
OBJECTIVES
Type III aortic arch configuration consistently presents anatomical and biomechanical characteristics which have been associated with an increased risk of type B aortic dissection (TBD). Our aim was to investigate the prevalence of type III arch in patients with TBD and type B intramural haematoma (IMH-B).
METHODS
A multicentre retrospective analysis was performed on patients with TBD and IMH-B observed between 2002 and 2017. The computed tomographic images were reviewed to identify the type of aortic arch. Exclusion criteria included previous arch surgery, presence of aortic dissection or aneurysm proximal to the left subclavian artery and bovine arches. An ad hoc systematic literature review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines to assess the prevalence of type III arch in non-TBD and non-aneurysmal patients.
RESULTS
Two hundred and sixty-one patients with TBD/IMH-B were found to be suitable for the study and were stratified according to aortic arch classification. The ad hoc literature search provided 10 relevant articles, from which a total of 7983 control cases were retrieved. TBD/IMH-B patients were significantly younger than controls [64.3, standard error: 0.74 (62.84–65.76) vs mean pooled age 70.5, standard error: 0.40 (69.71–71.28)]. Patients with TBD/IMH-B presented with a significantly higher prevalence of type III arch [41.0% (107/261) (35.2–47.1)] than controls [16% (1241/7983) (10–22)].
CONCLUSIONS
Our data indicate an association between type III arch configuration and the occurrence of TBD/IMH-B. These findings warrant further studies to disclose the potential role of type III arch configuration as an anatomical risk factor for TBD/IMH-B.
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Affiliation(s)
- Massimiliano M Marrocco-Trischitta
- Division of Vascular Surgery II, IRCCS - Policlinico San Donato, San Donato Milanese, Italy
- Thoracic Aortic Research Center, IRCCS - Policlinico San Donato, San Donato Milanese, Italy
| | - Bartosz Rylski
- Department of Cardiovascular Surgery, Faculty of Medicine, Albert Ludwigs University, University Heart Center Freiburg, Freiburg, Germany
| | - Florian Schofer
- Department of Cardiovascular Surgery, Faculty of Medicine, Albert Ludwigs University, University Heart Center Freiburg, Freiburg, Germany
| | - Francesco Secchi
- Division of Radiology, IRCCS - Policlinico San Donato, San Donato Milanese, Italy
| | - Gabriele Piffaretti
- Vascular Surgery, Department of Medicine and Surgery, University of Insubria School of Medicine, ASST Settelaghi University Teaching Hospital, Varese, Italy
| | - Hector de Beaufort
- Thoracic Aortic Research Center, IRCCS - Policlinico San Donato, San Donato Milanese, Italy
| | - Viony Belvroy
- Houston Methodist DeBakey Heart & Vascular Center, Houston, TX, USA
| | - Jean Bismuth
- Houston Methodist DeBakey Heart & Vascular Center, Houston, TX, USA
| | - Martin Czerny
- Department of Cardiovascular Surgery, Faculty of Medicine, Albert Ludwigs University, University Heart Center Freiburg, Freiburg, Germany
| | - Santi Trimarchi
- Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico Milan, Milan, Italy
- Department of Clinical and Community Sciences, University of Milan, Milan, Italy
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Jiang D, Kuang F, Lai Y, Shan Z, Chen Q. Certain aortic geometries and hemodynamics are associated with FID development and impact the evolution of uncomplicated type B intramural hematoma during the acute phase. J Card Surg 2019; 34:337-347. [PMID: 30932260 DOI: 10.1111/jocs.14040] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 02/27/2019] [Accepted: 03/14/2019] [Indexed: 01/16/2023]
Abstract
OBJECTIVES It is difficult to predict the evolution of uncomplicated type B intramural hematoma (IMHB) with a focal intimal disruption (FID) in the acute phase. The aims of this study were to investigate the predictors of FIDs and summarize the risk factors for the evolution of uncomplicated IMHB in the acute phase. METHODS Eighty-six patients with uncomplicated IMHB were included and were divided according to the development of an FID during the acute phase: the FID group (n = 32) and the no-FID group (n = 54). Geometric measurements and computed fluid dynamic calculations were based on a computed tomography scan performed on admission. Multivariate logistic regression analysis was used to estimate the predictors of FID development. RESULTS Thirty-two (37%) patients developed an FID. Patients with an FID had higher C-reactive protein levels (18.6 ± 2.3 vs 8.1 ± 0.2 mg/dL, P < 0.001) and white blood cell counts (10.3 ± 2.1 vs 7.5 ± 1.7 109 /L, P < 0.001). The no-FID group had lower occurrences of disease progression (15% vs 64%, P < 0.001) and aorta-related mortality (6% vs 25%, P = 0.016). Multivariate logistic regression analysis indicated a significant risk for the occurrence of an FID with a larger maximum aortic diameter (OR, 1.35; 95% CI, 1.05-1.73, P = 0.020), thicker hematoma (OR, 2.20; 95% CI, 1.40-3.48, P = 0.001), and higher oscillatory shear index (per 0.01 unit, OR, 1.74; 95% CI, 1.21-2.49, P = 0.003). The aorta-related mortality during the acute phase was 25% (n = 8). CONCLUSIONS Certain aortic conditions, including ta larger aortic diameter, thicker hematoma and higher oscillatory shear stress, are associated with the FID development and result in worse clinical outcomes.
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Affiliation(s)
- Dandan Jiang
- Department of Internal Medicine, The First Affiliated Hospital of Xiamen University, Teaching Hospital of Fujian Medical University, Xiamen, Fujian, China
| | - Feng Kuang
- Department of Cardiovascular Surgery, The First Affiliated Hospital of Xiamen University, Teaching Hospital of Fujian Medical University, Xiamen, Fujian, China
| | - Yiquan Lai
- Department of Cardiovascular Surgery, The First Affiliated Hospital of Xiamen University, Teaching Hospital of Fujian Medical University, Xiamen, Fujian, China
| | - Zhonggui Shan
- Department of Cardiovascular Surgery, The First Affiliated Hospital of Xiamen University, Teaching Hospital of Fujian Medical University, Xiamen, Fujian, China
| | - Qu Chen
- Department of Cardiovascular Surgery, The First Affiliated Hospital of Xiamen University, Teaching Hospital of Fujian Medical University, Xiamen, Fujian, China
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Wei W, Evin M, Rapacchi S, Kober F, Bernard M, Jacquier A, Kahn CJF, Behr M. Investigating heartbeat-related in-plane motion and stress levels induced at the aortic root. Biomed Eng Online 2019; 18:19. [PMID: 30808342 PMCID: PMC6391796 DOI: 10.1186/s12938-019-0632-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Accepted: 01/31/2019] [Indexed: 12/28/2022] Open
Abstract
Background The axial motion of aortic root (AR) due to ventricular traction was previously suggested to contribute to ascending aorta (AA) dissection by increasing its longitudinal stress, but AR in-plane motion effects on stresses have never been studied. The objective is to investigate the contribution of AR in-plane motion to AA stress levels. Methods The AR in-plane motion was assessed on magnetic resonance imagining data from 25 healthy volunteers as the movement of the AA section centroid. The measured movement was prescribed to the proximal AA end of an aortic finite element model to investigate its influences on aortic stresses. The finite element model was developed from a patient-specific geometry using LS-DYNA solver and validated against the aortic distensibility. Fluid–structure interaction (FSI) approach was also used to simulate blood hydrodynamic effects on aortic dilation and stresses. Results The AR in-plane motion was 5.5 ± 1.7 mm with the components of 3.1 ± 1.5 mm along the direction of proximal descending aorta (PDA) to AA centroid and 3.0 ± 1.3 mm perpendicularly under the PDA reference system. The AR axial motion elevated the longitudinal stress of proximal AA by 40% while the corresponding increase due to in-plane motion was always below 5%. The stresses at proximal AA resulted approximately 7% less in FSI simulation with blood flow. Conclusions The AR in-plane motion was comparable with the magnitude of axial motion. Neither axial nor in-plane motion could directly lead to AA dissection. It is necessary to consider the heterogeneous pressures related to blood hydrodynamics when studying aortic wall stress levels. Electronic supplementary material The online version of this article (10.1186/s12938-019-0632-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Wei Wei
- Laboratoire de Biomécanique Appliquée, Aix-Marseille Université, IFSTTAR, LBA, UMR T24, 51 Bd. P. Dramard, 13015, Marseille, France.
| | - Morgane Evin
- Laboratoire de Biomécanique Appliquée, Aix-Marseille Université, IFSTTAR, LBA, UMR T24, 51 Bd. P. Dramard, 13015, Marseille, France
| | | | - Frank Kober
- Aix-Marseille Université, CNRS, CRMBM, UMR 7339, Marseille, France
| | - Monique Bernard
- Aix-Marseille Université, CNRS, CRMBM, UMR 7339, Marseille, France
| | - Alexis Jacquier
- Aix-Marseille Université, CNRS, CRMBM, UMR 7339, Marseille, France
| | - Cyril J F Kahn
- Laboratoire de Biomécanique Appliquée, Aix-Marseille Université, IFSTTAR, LBA, UMR T24, 51 Bd. P. Dramard, 13015, Marseille, France
| | - Michel Behr
- Laboratoire de Biomécanique Appliquée, Aix-Marseille Université, IFSTTAR, LBA, UMR T24, 51 Bd. P. Dramard, 13015, Marseille, France
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Korenczuk CE, Votava LE, Dhume RY, Kizilski SB, Brown GE, Narain R, Barocas VH. Isotropic Failure Criteria Are Not Appropriate for Anisotropic Fibrous Biological Tissues. J Biomech Eng 2019; 139:2613842. [PMID: 28334369 DOI: 10.1115/1.4036316] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The von Mises (VM) stress is a common stress measure for finite element models of tissue mechanics. The VM failure criterion, however, is inherently isotropic, and therefore may yield incorrect results for anisotropic tissues, and the relevance of the VM stress to anisotropic materials is not clear. We explored the application of a well-studied anisotropic failure criterion, the Tsai–Hill (TH) theory, to the mechanically anisotropic porcine aorta. Uniaxial dogbones were cut at different angles and stretched to failure. The tissue was anisotropic, with the circumferential failure stress nearly twice the axial (2.67 ± 0.67 MPa compared to 1.46 ± 0.59 MPa). The VM failure criterion did not capture the anisotropic tissue response, but the TH criterion fit the data well (R2 = 0.986). Shear lap samples were also tested to study the efficacy of each criterion in predicting tissue failure. Two-dimensional failure propagation simulations showed that the VM failure criterion did not capture the failure type, location, or propagation direction nearly as well as the TH criterion. Over the range of loading conditions and tissue geometries studied, we found that problematic results that arise when applying the VM failure criterion to an anisotropic tissue. In contrast, the TH failure criterion, though simplistic and clearly unable to capture all aspects of tissue failure, performed much better. Ultimately, isotropic failure criteria are not appropriate for anisotropic tissues, and the use of the VM stress as a metric of mechanical state should be reconsidered when dealing with anisotropic tissues.
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Emerel L, Thunes J, Kickliter T, Billaud M, Phillippi JA, Vorp DA, Maiti S, Gleason TG. Predissection-derived geometric and distensibility indices reveal increased peak longitudinal stress and stiffness in patients sustaining acute type A aortic dissection: Implications for predicting dissection. J Thorac Cardiovasc Surg 2018; 158:355-363. [PMID: 30551966 DOI: 10.1016/j.jtcvs.2018.10.116] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Revised: 10/17/2018] [Accepted: 10/26/2018] [Indexed: 01/16/2023]
Abstract
OBJECTIVE To assess ascending aortic distensibility and build geometry and distensibility-based patient-specific stress distribution maps in patients sustaining type A aortic dissection (TAAD) using predissection noninvasive imaging. METHODS Review of charts from patients undergoing surgical repair of TAAD (n = 351) led to the selection of a subset population (n = 7) with 2 or more predissection computed tomography angiography scans and echocardiograms at least 1 year before dissection. Ascending aortic wall biomechanical properties (aortic strain, distensibility, and stiffness) were compared with age- and size-matched nondissected nonaneurysmal controls. Patient-specific aortic strain served as an input in aortic geometry-based simulated 3-dimensional reconstructions to generate longitudinal and circumferential wall stress maps. Inspection of perioperative dissection scans and intraoperative visual examination confirmed primary tear locations. RESULTS Predissection echocardiography revealed ascending aortas of patients sustaining TAAD to exhibit decreased aortic wall strain (14.50 ± 1.13% vs 8.49 ± 1.08%; P < .01), decreased distensibility (4.26 ± 0.44 vs 2.39 ± 0.33 10-6 cm2·dyne-1; P < .01), increased stiffness (3.84 ± 0.24 vs 7.48 ± 1.05; P < .001), and increased longitudinal wall stress (246 ± 22 vs 172 ± 37 kPa; P < .01). There was no significant difference in circumferential wall stress. Predissection computed tomography angiography models revealed overlap between regions of increased longitudinal wall stress and primary tear sites. CONCLUSIONS Using predissection imaging, we identified increased stiffness and longitudinal wall stress in ascending aortas of patients with dissection. Patient-specific imaging-derived biomechanical property maps like these may be instrumental toward designing better prediction models of aortic dissection potential.
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Affiliation(s)
- Leonid Emerel
- Department of Cardiothoracic Surgery, University of Pittsburgh, Pittsburgh, Pa
| | - James Thunes
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pa
| | - Trevor Kickliter
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pa
| | - Marie Billaud
- Department of Cardiothoracic Surgery, University of Pittsburgh, Pittsburgh, Pa; Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pa; McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, Pa
| | - Julie A Phillippi
- Department of Cardiothoracic Surgery, University of Pittsburgh, Pittsburgh, Pa; Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pa; McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, Pa; Center for Vascular Remodeling and Regeneration, University of Pittsburgh, Pittsburgh, Pa
| | - David A Vorp
- Department of Cardiothoracic Surgery, University of Pittsburgh, Pittsburgh, Pa; Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pa; McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, Pa; Center for Vascular Remodeling and Regeneration, University of Pittsburgh, Pittsburgh, Pa; Department of Chemical & Petroleum Engineering, University of Pittsburgh, Pittsburgh, Pa
| | - Spandan Maiti
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pa
| | - Thomas G Gleason
- Department of Cardiothoracic Surgery, University of Pittsburgh, Pittsburgh, Pa; Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pa; McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, Pa; Center for Vascular Remodeling and Regeneration, University of Pittsburgh, Pittsburgh, Pa; Center for Thoracic Aortic Disease, University of Pittsburgh, Pittsburgh, Pa.
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Campobasso R, Condemi F, Viallon M, Croisille P, Campisi S, Avril S. Evaluation of Peak Wall Stress in an Ascending Thoracic Aortic Aneurysm Using FSI Simulations: Effects of Aortic Stiffness and Peripheral Resistance. Cardiovasc Eng Technol 2018; 9:707-722. [DOI: 10.1007/s13239-018-00385-z] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2018] [Accepted: 10/08/2018] [Indexed: 12/25/2022]
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Mendez V, Di Giuseppe M, Pasta S. Comparison of hemodynamic and structural indices of ascending thoracic aortic aneurysm as predicted by 2-way FSI, CFD rigid wall simulation and patient-specific displacement-based FEA. Comput Biol Med 2018; 100:221-229. [DOI: 10.1016/j.compbiomed.2018.07.013] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 07/17/2018] [Accepted: 07/18/2018] [Indexed: 10/28/2022]
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Hemodynamics in diabetic human aorta using computational fluid dynamics. PLoS One 2018; 13:e0202671. [PMID: 30138473 PMCID: PMC6107202 DOI: 10.1371/journal.pone.0202671] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Accepted: 08/07/2018] [Indexed: 02/04/2023] Open
Abstract
Three-dimensional (3D) computational aortic models have been established to reproduce aortic diseases such as aortic aneurysm and dissection; however, no such models have been developed to study diabetes mellitus (DM). To characterize biomechanical properties of the human aorta with DM, reconstructed aortic CT images were converted into DICOM format, and imported into the 3D segmentation using Mimics software. This resulted in a 3D reconstruction of the complete aorta, including three branches. We applied a pulsatile blood pressure waveform for the ascending aorta to provide a biomimetic environment using COMSOL Multiphysics software. Hemodynamics were compared between the control and DM models. We observed that mean blood flow velocity, aortic pressure, and von Mises stress values were lower in the DM model than in the control model. Furthermore, the range of aortic movement was lower in the DM model than in the control model, suggesting that the DM aortic wall is more susceptible to rupture. When comparing biomechanical properties in discrete regions of the aorta, all values were higher in the ascending aorta for both control and DM models, corresponding to the location of most aortic lesions. We have developed a compute based that integrates advanced image processing strategies and computational techniques based on finite element method to perform hemodynamics analysis based on CT images. Our study of image-based CFD analysis hopes to provide a better understanding of the relationship between aortic hemodynamic and developing pathophysiology of aortic diseases.
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Affiliation(s)
- Ibrahim Akin
- Cardiology, Universitätsmedizin Mannheim, Mannheim, Germany
- DZHK, DZHK (Deutsches Zentrum für Herz-Kreislaufforschung), Mannheim, Germany
| | - Christoph A Nienaber
- Cardiology and Aortic Centre, Royal Brompton Hospital and Harefield Trust, London, UK
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Doyle BJ, Norman PE, Hoskins PR, Newby DE, Dweck MR. Wall Stress and Geometry of the Thoracic Aorta in Patients With Aortic Valve Disease. Ann Thorac Surg 2018; 105:1077-1085. [DOI: 10.1016/j.athoracsur.2017.11.061] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Revised: 11/07/2017] [Accepted: 11/27/2017] [Indexed: 10/18/2022]
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