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Pantoja JL, Shehadeh TS, Lee MM, Eldredge JD, Kiang SC. Geometrical Factors Affect Wall Shear Stress in Saccular Aneurysms of the Infrarenal Abdominal Aorta. Ann Vasc Surg 2024; 108:76-83. [PMID: 38942368 DOI: 10.1016/j.avsg.2024.04.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Accepted: 04/06/2024] [Indexed: 06/30/2024]
Abstract
BACKGROUND Low wall shear stress (WSS) is predictive of aortic aneurysm growth and rupture. Yet, estimating WSS in a clinical setting is impractical, whereas measuring aneurysm geometry is feasible. This study investigates the association between saccular aneurysm geometry of the infrarenal aorta and WSS. METHODS Starting with a nonaneurysmal, patient-specific, computational fluid dynamics model of the aorta, saccular aneurysms of varying geometry were created by incrementally increasing the neck width and sac depth from 1 cm to 4 cm. The aspect ratio (the ratio between sac depth and neck width) varied between 0.25 and 4. The peak WSS, time-averaged WSS (TAWSS), and oscillatory shear index (OSI) were measured within the aneurysm sac. RESULTS Decreasing the neck width from 4 cm to 1 cm decreased the peak WSS by 69% and the TAWSS by 83%. Increasing the sac depth from 1 cm to 4 cm decreased the peak WSS by 55% and the OSI by 37%. The aspect ratio was negatively correlated to peak WSS (Rs -0.85; P < 0.001). CONCLUSIONS In saccular aneurysms of the infrarenal aorta, a smaller neck width, deeper aneurysm sac, and larger aspect ratio are associated with lower peak WSS.
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Affiliation(s)
- Joe Luis Pantoja
- Division of Vascular Surgery, VA Loma Linda Healthcare System, Loma Linda, CA.
| | - Thaer S Shehadeh
- Division of Vascular Surgery, VA Loma Linda Healthcare System, Loma Linda, CA
| | - Mary M Lee
- Division of Vascular Surgery, VA Loma Linda Healthcare System, Loma Linda, CA
| | - Jeffrey D Eldredge
- Department of Mechanical & Aerospace Engineering, University of California, Los Angeles, CA
| | - Sharon C Kiang
- Division of Vascular Surgery, VA Loma Linda Healthcare System, Loma Linda, CA
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2
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Vitásek R, Kubíček L, Schwarz D, Staffa R, Polzer S. Tension-based abdominal aortic aneurysm rupture risk assessment improves its accuracy and reduces the time of analysis. J Biomech 2024; 176:112328. [PMID: 39357344 DOI: 10.1016/j.jbiomech.2024.112328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2024] [Revised: 07/22/2024] [Accepted: 09/12/2024] [Indexed: 10/04/2024]
Abstract
The biomechanical rupture risk assessment (BRRA) of abdominal aortic aneurysms (AAA) has higher sensitivity than maximal diameter criterion (DSEX) but its estimation is time-consuming and relies on an uncertain estimation of wall thickness. The aim of this study is to test tension-based criterion in the BRRA of AAA which removes the necessity of wall thickness measurement and should be faster. For that, we retrospectively analyzed 99 patients with intact AAA (25 females). Nineteen of them experienced a rupture later. BRRA was performed with wall tension PRRIT as a primary criterion. The ability of criterion to separate intact and ruptured AAAs at 1,3,6,9 and 12 months was estimated. Next, the receiver operating characteristics and the percentage of true negative cases for a different time to an outcome were estimated. Finally, the computational time was recorded. The results were compared to stress-based criterion PRRI and DSEX which served as a reference. All three criterions were able to discriminate between intact and ruptured AAAs up to 9 months (p < 0.05) while none of them could do for a 12 month prediction. PRRIT exhibited a significantly higher percentage of true negatives for 12 and 9 month predictions (45 % and 20 % respectively) and similar to other criteria for other prediction times. The mean computational time for estimating PRRIT was 19 h per patient compared to 67 h for PRRI. The tension- based BRRA of AAA leads to better outcomes for a 9 and 12 month prediction while the computational time drops by more than 70 % compared to PRRI.
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Affiliation(s)
- Radek Vitásek
- Department of Applied Mechanics, VSB-Technical University of Ostrava, Ostrava, Czech Republic.
| | - Luboš Kubíček
- 2nd Department of Surgery, St. Anne's University Hospital Brno and Faculty of Medicine, Masaryk University, Brno, Czech Republic.
| | - David Schwarz
- Department of Applied Mechanics, VSB-Technical University of Ostrava, Ostrava, Czech Republic.
| | - Robert Staffa
- 2nd Department of Surgery, St. Anne's University Hospital Brno and Faculty of Medicine, Masaryk University, Brno, Czech Republic.
| | - Stanislav Polzer
- Department of Applied Mechanics, VSB-Technical University of Ostrava, Ostrava, Czech Republic.
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3
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Salih A, Hamandi F, Goswami T. Advancements in Finite Element Modeling for Cardiac Device Leads and 3D Heart Models. Bioengineering (Basel) 2024; 11:564. [PMID: 38927800 PMCID: PMC11201100 DOI: 10.3390/bioengineering11060564] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2024] [Revised: 05/17/2024] [Accepted: 05/29/2024] [Indexed: 06/28/2024] Open
Abstract
The human heart's remarkable vitality necessitates a deep understanding of its mechanics, particularly concerning cardiac device leads. This paper presents advancements in finite element modeling for cardiac leads and 3D heart models, leveraging computational simulations to assess lead behavior over time. Through detailed modeling and meshing techniques, we accurately captured the complex interactions between leads and heart tissue. Material properties were assigned based on ASTM (American Society for Testing and Materials) standards and in vivo exposure data, ensuring realistic simulations. Our results demonstrate close agreement between experimental and simulated data for silicone insulation in pacemaker leads, with a mean force tolerance of 19.6 N ± 3.6 N, an ultimate tensile strength (UTS) of 6.3 MPa ± 1.15 MPa, and a percentage elongation of 125% ± 18.8%, highlighting the effectiveness of simulation in predicting lead performance. Similarly, for polyurethane insulation in ICD leads, we found a mean force of 65.87 N ± 7.1 N, a UTS of 10.7 MPa ± 1.15 MPa, and a percentage elongation of 259.3% ± 21.4%. Additionally, for polyurethane insulation in CRT leads, we observed a mean force of 53.3 N ± 2.06 N, a UTS of 22.11 MPa ± 0.85 MPa, and a percentage elongation of 251.6% ± 13.2%. Correlation analysis revealed strong relationships between mechanical properties, further validating the simulation models. Classification models constructed using both experimental and simulated data exhibited high discriminative ability, underscoring the reliability of simulation in analyzing lead behavior. These findings contribute to the ongoing efforts to improve cardiac device lead design and optimize patient outcomes.
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Affiliation(s)
- Anmar Salih
- Department of Biomedical, Industrial and Human Factors Engineering, Wright State University, Dayton, OH 45435, USA;
| | - Farah Hamandi
- Department of Biomedical, Industrial and Human Factors Engineering, Wright State University, Dayton, OH 45435, USA;
| | - Tarun Goswami
- Department of Biomedical, Industrial and Human Factors Engineering, Wright State University, Dayton, OH 45435, USA;
- Department of Orthopedic Surgery, Sports Medicine and Rehabilitation, Miami Valley Hospital, Dayton, OH 45409, USA
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Alkhatib F, Wittek A, Zwick BF, Bourantas GC, Miller K. Computation for biomechanical analysis of aortic aneurysms: the importance of computational grid. Comput Methods Biomech Biomed Engin 2024; 27:994-1010. [PMID: 37264784 DOI: 10.1080/10255842.2023.2218521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Accepted: 05/22/2023] [Indexed: 06/03/2023]
Abstract
Aortic wall stress is the most common variable of interest in abdominal aortic aneurysm (AAA) rupture risk assessment. Computation of such stress has been dominated by finite element analysis. However, the effects of finite element (FE) formulation, element quality, and methods of FE mesh construction on the efficiency, robustness, and accuracy of such computation have attracted little attention. In this study, we fill this knowledge gap by comparing the results of the calculated aortic wall stress for ten AAA patients using tetrahedral and hexahedral meshes when varying the FE formulation (displacement-based and hybrid), FE shape functions, spatial integration scheme, and number of elements through the wall thickness.
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Affiliation(s)
- Farah Alkhatib
- Intelligent Systems for Medicine Laboratory, The University of Western Australia, Perth, Western Australia, Australia
| | - Adam Wittek
- Intelligent Systems for Medicine Laboratory, The University of Western Australia, Perth, Western Australia, Australia
| | - Benjamin F Zwick
- Intelligent Systems for Medicine Laboratory, The University of Western Australia, Perth, Western Australia, Australia
| | - George C Bourantas
- Intelligent Systems for Medicine Laboratory, The University of Western Australia, Perth, Western Australia, Australia
- Department of Agriculture, University of Patras, Rio, Greece
| | - Karol Miller
- Intelligent Systems for Medicine Laboratory, The University of Western Australia, Perth, Western Australia, Australia
- Harvard Medical School, Boston, MA, USA
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5
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Ren S, Guidoin R, Xu Z, Deng X, Fan Y, Chen Z, Sun A. Narrative Review of Risk Assessment of Abdominal Aortic Aneurysm Rupture Based on Biomechanics-Related Morphology. J Endovasc Ther 2024; 31:178-190. [PMID: 36052406 DOI: 10.1177/15266028221119309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
CLINICAL IMPACT Studies have shown that the biomechanical indicators based on multi-scale models are more effective in accurately assessing the rupture risk of AAA. To meet the need for clinical monitoring and rapid decision making, the typical morphological parameters associated with AAA rupture and their relationships with the mechanical environment have been summarized, which provide a reference for clinical preoperative risk assessment of AAA.
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Affiliation(s)
- Shuqi Ren
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Robert Guidoin
- Department of Surgery, Faculty of Medicine, Université Laval and CHU de Québec Research Centre, Quebec, QC, Canada
| | - Zaipin Xu
- College of Animal Science, Guizhou University, Guiyang, China
| | - Xiaoyan Deng
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Yubo Fan
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Zengsheng Chen
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Anqiang Sun
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
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Derwich W, Schönborn M, Blase C, Wittek A, Oikonomou K, Böckler D, Erhart P. Correlation of four-dimensional ultrasound strain analysis with computed tomography angiography wall stress simulations in abdominal aortic aneurysms. JVS Vasc Sci 2024; 5:100199. [PMID: 38633883 PMCID: PMC11022090 DOI: 10.1016/j.jvssci.2024.100199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Accepted: 03/09/2024] [Indexed: 04/19/2024] Open
Abstract
Objective Biomechanical modeling of infrarenal aortic aneurysms seeks to predict ruptures in advance, thereby reducing aneurysm-related deaths. As individual methods focusing on strain and stress analysis lack adequate discretization power, this study aims to explore multifactorial characterization for progressive aneurysmal degeneration. The study's objective is to compare stress- and strain-related parameters in infrarenal aortic aneurysms. Methods Twenty-two patients with abdominal aortic aneurysms (AAAs) (mean maximum diameter, 53.2 ± 7.2 mm) were included in the exploratory study, examined by computed tomography angiography (CTA) and three-dimensional real-time speckle tracking ultrasound (4D-US). The conformity of aneurysm anatomy in 4D-US and CTA was determined with the mean point-to-point distance (MPPD). CTA was employed for each AAA to characterize stress-related indices using the semi-automated A4-clinics RE software. Five segmentations from one 4D-US examination were fused into one averaged model for strain analysis using MATLAB and the Abaqus solver. Results The mean MPPD between the adjacent points of the 4D-US and CTA-derived geometry was 1.8 ± 0.4 mm. The interclass correlation coefficients for all raters and all measurements for the maximum AAA diameter in 2D, 4D ultrasound, and CTA indicate moderate to good reliability (interclass correlation coefficient1 0.69 with 95% confidence interval [CI], 0.49-0.84; P < .001). The peak wall stress (PWS) correlates fairly with the maximum AAA diameter in 2D-US (r = 0.54; P < .01) and 4D-US (r = 0.53; P < .05) and moderately strongly with the maximum exterior AAA diameter (r = 0.63; P < .01). The peak wall rupture risk index shows a strong correlation with the PWS (ρ > 0.9; P < .001) and is influenced by anatomical parameters with equal strength. Isolated observation of the intraluminal thrombus does not provide significant information in the determination of PWS. The maximum AAA diameter in 2D-US shows a fair negative correlation with the mean circumferential, longitudinal and in-plane shear strain (ρ = -0.46; r = -0.45; ρ = -0.47; P < .05 for all). The circumferential strain ratio as an indicator of wall motion heterogeneity increases with the aneurysm diameter (r = 0.47; P < .05). The direct comparison of wall strain and wall stress indices shows no quantitative correlation. Conclusions The strain and stress analyses provide independent biomechanical information of AAAs. At the current stage of development, the two methods are considered complementary and may optimize a more patient-specific rupture risk prediction in the future.
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Affiliation(s)
- Wojciech Derwich
- Vascular and Endovascular Surgery, Department of Cardiac and Vascular Surgery, University Hospital Frankfurt Goethe University, Frankfurt/Main, Germany
| | - Manuel Schönborn
- Personalized Biomedical Engineering Lab, Frankfurt University of Applied Sciences, Frankfurt/Main, Germany
| | - Christopher Blase
- Personalized Biomedical Engineering Lab, Frankfurt University of Applied Sciences, Frankfurt/Main, Germany
| | - Andreas Wittek
- Personalized Biomedical Engineering Lab, Frankfurt University of Applied Sciences, Frankfurt/Main, Germany
| | - Kyriakos Oikonomou
- Vascular and Endovascular Surgery, Department of Cardiac and Vascular Surgery, University Hospital Frankfurt Goethe University, Frankfurt/Main, Germany
| | - Dittmar Böckler
- Department of Vascular and Endovascular Surgery, Heidelberg University Hospital, Heidelberg, Germany
| | - Philipp Erhart
- Department of Vascular and Endovascular Surgery, Heidelberg University Hospital, Heidelberg, Germany
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Özcan C, Kocatürk Ö, Işlak C, Öztürk C. Integrated particle image velocimetry and fluid-structure interaction analysis for patient-specific abdominal aortic aneurysm studies. Biomed Eng Online 2023; 22:113. [PMID: 38044423 PMCID: PMC10693692 DOI: 10.1186/s12938-023-01179-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Accepted: 11/23/2023] [Indexed: 12/05/2023] Open
Abstract
BACKGROUND Understanding the hemodynamics of an abdominal aortic aneurysm (AAA) is crucial for risk assessment and treatment planning. This study introduces a low-cost, patient-specific in vitro AAA model to investigate hemodynamics using particle image velocimetry (PIV) and flow-simulating circuit, validated through fluid-structure interaction (FSI) simulations. METHODS In this study, 3D printing was employed to manufacture a flexible patient-specific AAA phantom using a lost-core casting technique. A pulsatile flow circuit was constructed using off-the-shelf components. A particle image velocimetry (PIV) setup was built using an affordable laser source and global shutter camera, and finally, the flow field inside the AAA was analyzed using open-source software. Fluid-structure interaction (FSI) simulations were performed to enhance our understanding of the flow field, and the results were validated by PIV analysis. Both steady-state and transient flow conditions were investigated. RESULTS Our experimental setup replicated physiological conditions, analyzing arterial wall deformations and flow characteristics within the aneurysm. Under constant flow, peak wall deformations and flow velocities showed deviations within - 12% to + 27% and - 7% to + 5%, respectively, compared to FSI simulations. Pulsatile flow conditions further demonstrated a strong correlation (Pearson coefficient 0.85) in flow velocities and vectors throughout the cardiac cycle. Transient phenomena, particularly the formation and progression of vortex structures during systole, were consistently depicted between experimental and numerical models. CONCLUSIONS By bridging high-fidelity experimental observations with comprehensive computational analyses, this study underscores the potential of integrated methodologies in enhancing our understanding of AAA pathophysiology. The convergence of realistic AAA phantoms, precise PIV measurements at affordable cost point, and validated FSI models heralds a new paradigm in vascular research, with significant implications for personalized medicine and bioengineering innovations.
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Affiliation(s)
- Can Özcan
- Institute of Biomedical Engineering, Boğaziçi University, Kandilli Campus, Feza Gürsey Bld., Çengelköy, 34685, Istanbul, Turkey.
| | - Özgür Kocatürk
- Institute of Biomedical Engineering, Boğaziçi University, Kandilli Campus, Feza Gürsey Bld., Çengelköy, 34685, Istanbul, Turkey
| | - Civan Işlak
- Department of Radiology, Division of Neuroradiology, Cerrahpaşa Medical Faculty, Istanbul University Cerrahpaşa, Istanbul, Turkey
| | - Cengizhan Öztürk
- Institute of Biomedical Engineering, Boğaziçi University, Kandilli Campus, Feza Gürsey Bld., Çengelköy, 34685, Istanbul, Turkey
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8
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De Freitas S, Falls G, Weis T, Bakhshi K, Korepta LM, Bechara CF, Erben Y, Arya S, Fatima J. Comprehensive framework of factors accounting for worse aortic aneurysm outcomes in females: A scoping review. Semin Vasc Surg 2023; 36:508-516. [PMID: 38030325 DOI: 10.1053/j.semvascsurg.2023.10.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2023] [Revised: 10/15/2023] [Accepted: 10/18/2023] [Indexed: 12/01/2023]
Abstract
Sex-based outcome studies have consistently documented worse results for females undergoing care for abdominal aortic aneurysms. This review explores the underlying factors that account for worse outcomes in the females sex. A scoping review of studies reporting sex-based disparities on abdominal aortic aneurysms was performed. The review was conducted in accordance with the Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for scoping reviews. Factors that account for worse outcomes in the females sex were identified, grouped into themes, and analyzed. Key findings of each study are reported and a comprehensive framework of these factors is presented. A total of 35 studies were identified as critical in highlighting sex-based disparities in care of patients with aortic aneurysms. We identified the following 10 interrelated themes in the chain of aneurysm care that account for differential outcomes in females: natural history, risk factors, pathobiology, biomechanics, screening, morphology, device design and adherence to instructions for use, technique, trial enrollment, and social determinants. Factors accounting for worse outcomes in the care of females with aortic aneurysms were identified and described. Some factors are immediately actionable, such as screening criteria, whereas device design improvement will require further research and development. This comprehensive framework of factors affecting care of aneurysms in females should serve as a blueprint to develop education, outreach, and future research efforts to improve outcomes in females.
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Affiliation(s)
| | | | - Tahlia Weis
- Marshfield Clinic Health System, Marshfield, WI
| | | | | | | | | | - Shipra Arya
- Stanford University School of Medicine, Stanford, CA
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9
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Margaretha Nievergeld AH, Maas EJ, de Ruijter J, Cornelia Fonken JH, Henricus Maria van Sambeek MR, Paulus Lopata RG. Automatic Segmentation and Mechanical Characterisation of the Intraluminal Thrombus and Arterial Wall of Abdominal Aortic Aneurysms Using Time Resolved 3D Ultrasound Images. Eur J Vasc Endovasc Surg 2023; 66:418-427. [PMID: 36963747 DOI: 10.1016/j.ejvs.2023.03.033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 01/19/2023] [Accepted: 03/17/2023] [Indexed: 03/26/2023]
Abstract
OBJECTIVE This study proposed a method for semi-automatic segmentation of abdominal aortic aneurysms (AAAs) and their intraluminal thrombus (ILT), based on time resolved 3D ultrasound (US), and validated results with computed tomography (CT). Mechanical properties of both wall and ILT were determined, and possible correlations with ILT size and blood pressure were investigated. METHODS A semi-automatic segmentation algorithm was developed combining a star-Kalman approach with a 3D snake algorithm. The segmented geometries of both lumen and inner vessel wall were validated with both manual US based segmentations and CT based segmentations. Finally, the lumen and vessel wall distensibility and ILT compressibility were estimated and correlated with ILT size and blood pressure. RESULTS For the vessel wall and lumen, the median Similarity Index (SI) was 92% (IQR 90, 94%) and 83% (IQR 75, 87%), respectively. The distensibility of the vessel wall could be determined in 37 of 40 cases and had a median value of 0.28 10-5 Pa-1 (IQR 0.18, 0.51 ×10-5). The median systolic to diastolic volume change of the ILT was determined successfully in 21 of 40 patients, and was -0.57% (IQR -1.1, 1.2%). The vessel and lumen distensibility showed a strong correlation with the systolic pressure (p < .010), rather than with the diastolic pressure. Lumen distensibility was strongly correlated with ILT thickness (p = .023). The performance of the semi-automatic segmentation algorithm was shown to be as good as the manual segmentations and highly dependent on the visibility of the ILT (limited contrast in seven patients and clutter in nine patients). CONCLUSION This study has shown promising results for mechanical characterisation of the vessel, and ILT, including a correlation between distensibility, ILT size, and blood pressure. For future work, the inclusion rate needs to be increased by improving the image contrast with novel US techniques.
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Affiliation(s)
- Arjet Helena Margaretha Nievergeld
- Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands; Department of Vascular Surgery, Catharina Hospital Eindhoven, Eindhoven, The Netherlands.
| | - Esther Jorien Maas
- Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands; Department of Vascular Surgery, Catharina Hospital Eindhoven, Eindhoven, The Netherlands
| | - Joerik de Ruijter
- Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Judith Helena Cornelia Fonken
- Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands; Department of Vascular Surgery, Catharina Hospital Eindhoven, Eindhoven, The Netherlands
| | - Marcus Rodolph Henricus Maria van Sambeek
- Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands; Department of Vascular Surgery, Catharina Hospital Eindhoven, Eindhoven, The Netherlands
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10
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Singh TP, Moxon JV, Gasser TC, Jenkins J, Bourke M, Bourke B, Golledge J. Association between aortic peak wall stress and rupture index with abdominal aortic aneurysm-related events. Eur Radiol 2023; 33:5698-5706. [PMID: 36897345 PMCID: PMC10326087 DOI: 10.1007/s00330-023-09488-1] [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: 06/25/2022] [Revised: 01/23/2023] [Accepted: 01/27/2023] [Indexed: 03/11/2023]
Abstract
OBJECTIVE The aim of this study was to assess whether aortic peak wall stress (PWS) and peak wall rupture index (PWRI) were associated with the risk of abdominal aortic aneurysm (AAA) rupture or repair (defined as AAA events) among participants with small AAAs. METHODS PWS and PWRI were estimated from computed tomography angiography (CTA) scans of 210 participants with small AAAs (≥ 30 and ≤ 50 mm) prospectively recruited between 2002 and 2016 from two existing databases. Participants were followed for a median of 2.0 (inter-quartile range 1.9, 2.8) years to record the incidence of AAA events. The associations between PWS and PWRI with AAA events were assessed using Cox proportional hazard analyses. The ability of PWS and PWRI to reclassify the risk of AAA events compared to the initial AAA diameter was examined using net reclassification index (NRI) and classification and regression tree (CART) analysis. RESULTS After adjusting for other risk factors, one standard deviation increase in PWS (hazard ratio, HR, 1.56, 95% confidence intervals, CI 1.19, 2.06; p = 0.001) and PWRI (HR 1.74, 95% CI 1.29, 2.34; p < 0.001) were associated with significantly higher risks of AAA events. In the CART analysis, PWRI was identified as the best single predictor of AAA events at a cut-off value of > 0.562. PWRI, but not PWS, significantly improved the classification of risk of AAA events compared to the initial AAA diameter alone. CONCLUSION PWS and PWRI predicted the risk of AAA events but only PWRI significantly improved the risk stratification compared to aortic diameter alone. KEY POINTS • Aortic diameter is an imperfect measure of abdominal aortic aneurysm (AAA) rupture risk. • This observational study of 210 participants found that peak wall stress (PWS) and peak wall rupture index (PWRI) predicted the risk of aortic rupture or AAA repair. • PWRI, but not PWS, significantly improved the risk stratification for AAA events compared to aortic diameter alone.
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Affiliation(s)
- Tejas P Singh
- Queensland Research Centre for Peripheral Vascular Disease, College of Medicine and Dentistry, James Cook University, Townsville, Queensland, 4811, Australia
- The Department of Vascular and Endovascular Surgery, The Townsville University Hospital, Townsville, Queensland, Australia
| | - Joseph V Moxon
- Queensland Research Centre for Peripheral Vascular Disease, College of Medicine and Dentistry, James Cook University, Townsville, Queensland, 4811, Australia
- The Australian Institute of Tropical Health and Medicine, James Cook University, Townsville, Queensland, Australia
| | - T Christian Gasser
- Department of Engineering Mechanics, KTH Solid Mechanics, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Jason Jenkins
- Department of Vascular and Endovascular Surgery, Royal Brisbane and Women's Hospital Brisbane, Herston, Queensland, Australia
| | - Michael Bourke
- Gosford Vascular Services Gosford New South Wales Australia, Gosford, Australia
- The School of Biomedical Sciences & Pharmacy, The University of Newcastle, Newcastle, New South Wales, Australia
| | - Benard Bourke
- Gosford Vascular Services Gosford New South Wales Australia, Gosford, Australia
| | - Jonathan Golledge
- Queensland Research Centre for Peripheral Vascular Disease, College of Medicine and Dentistry, James Cook University, Townsville, Queensland, 4811, Australia.
- The Department of Vascular and Endovascular Surgery, The Townsville University Hospital, Townsville, Queensland, Australia.
- The Australian Institute of Tropical Health and Medicine, James Cook University, Townsville, Queensland, Australia.
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11
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Wang X, Carpenter HJ, Ghayesh MH, Kotousov A, Zander AC, Amabili M, Psaltis PJ. A review on the biomechanical behaviour of the aorta. J Mech Behav Biomed Mater 2023; 144:105922. [PMID: 37320894 DOI: 10.1016/j.jmbbm.2023.105922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 05/14/2023] [Accepted: 05/20/2023] [Indexed: 06/17/2023]
Abstract
Large aortic aneurysm and acute and chronic aortic dissection are pathologies of the aorta requiring surgery. Recent advances in medical intervention have improved patient outcomes; however, a clear understanding of the mechanisms leading to aortic failure and, hence, a better understanding of failure risk, is still missing. Biomechanical analysis of the aorta could provide insights into the development and progression of aortic abnormalities, giving clinicians a powerful tool in risk stratification. The complexity of the aortic system presents significant challenges for a biomechanical study and requires various approaches to analyse the aorta. To address this, here we present a holistic review of the biomechanical studies of the aorta by categorising articles into four broad approaches, namely theoretical, in vivo, experimental and combined investigations. Experimental studies that focus on identifying mechanical properties of the aortic tissue are also included. By reviewing the literature and discussing drawbacks, limitations and future challenges in each area, we hope to present a more complete picture of the state-of-the-art of aortic biomechanics to stimulate research on critical topics. Combining experimental modalities and computational approaches could lead to more comprehensive results in risk prediction for the aortic system.
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Affiliation(s)
- Xiaochen Wang
- School of Electrical and Mechanical Engineering, The University of Adelaide, Adelaide, South Australia 5005, Australia.
| | - Harry J Carpenter
- School of Electrical and Mechanical Engineering, The University of Adelaide, Adelaide, South Australia 5005, Australia
| | - Mergen H Ghayesh
- School of Electrical and Mechanical Engineering, The University of Adelaide, Adelaide, South Australia 5005, Australia.
| | - Andrei Kotousov
- School of Electrical and Mechanical Engineering, The University of Adelaide, Adelaide, South Australia 5005, Australia
| | - Anthony C Zander
- School of Electrical and Mechanical Engineering, The University of Adelaide, Adelaide, South Australia 5005, Australia
| | - Marco Amabili
- Department of Mechanical Engineering, McGill University, Montreal H3A 0C3, Canada
| | - Peter J Psaltis
- Adelaide Medical School, The University of Adelaide, Adelaide, South Australia 5005, Australia; Department of Cardiology, Central Adelaide Local Health Network, Adelaide, South Australia 5000, Australia; Vascular Research Centre, Heart Health Theme, South Australian Health & Medical Research Institute (SAHMRI), Adelaide, South Australia 5000, Australia
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Koncar I, Nikolic D, Milosevic Z, Bogavac-Stanojevic N, Ilic N, Dragas M, Sladojevic M, Markovic M, Vujcic A, Filipovic N, Davidovic L. Abdominal aortic aneurysm volume and relative intraluminal thrombus volume might be auxiliary predictors of rupture-an observational cross-sectional study. Front Surg 2023; 10:1095224. [PMID: 37215356 PMCID: PMC10197926 DOI: 10.3389/fsurg.2023.1095224] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Accepted: 04/03/2023] [Indexed: 05/24/2023] Open
Abstract
Objectives The study aimed to identify differences and compare anatomical and biomechanical features between elective and ruptured abdominal aortic aneurysms (AAAs). Methods Data (clinical, anatomical, and biomechanical) of 98 patients with AAA, 75 (76.53%) asymptomatic (Group aAAA) and 23 (23.46%) ruptured AAA (Group rAAA), were prospectively collected and analyzed. Anatomical, morphological, and biomechanical imaging markers like peak wall stress (PWS) and rupture risk equivalent diameter (RRED), comorbid conditions, and demographics were compared between the groups. Biomechanical features were assessed by analysis of Digital Imaging and Communication in Medicine images by A4clinics (Vascops), and anatomical features were assessed by 3Surgery (Trimensio). Binary and multiple logistic regression analysis were used and adjusted for confounders. Accuracy was assessed using receiving operative characteristic (ROC) curve analysis. Results In a multivariable model, including gender and age as confounder variables, maximal aneurysm diameter [MAD, odds ratio (OR) = 1.063], relative intraluminal thrombus (rILT, OR = 1.039), and total aneurysm volume (TAV, OR = 1.006) continued to be significant predictors of AAA rupture with PWS (OR = 1.010) and RRED (OR = 1.031). Area under the ROC curve values and correct classification (cc) for the same parameters and the model that combines MAD, TAV, and rILT were measured: MAD (0.790, cc = 75%), PWS (0.713, cc = 73%), RRED (0.717, cc = 55%), TAV (0.756, cc = 79%), rILT (0.656, cc = 60%), and MAD + TAV + rILT (0.797, cc = 82%). Conclusion Based on our results, in addition to MAD, other important predictors of rupture that might be used during aneurysm surveillance are TAV and rILT. Biomechanical parameters (PWS, RRED) as valuable predictors should be assessed in prospective clinical trials. Similar studies on AAA smaller than 55 mm in diameter, even difficult to organize, would be of even greater clinical value.
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Affiliation(s)
- I. Koncar
- Faculty of Medicine, University of Belgrade, Belgrade, Serbia
- Clinic for Vascular and Endovascular Surgery, Clinical Center of Serbia, Belgrade, Serbia
| | - D. Nikolic
- Research and Development Center for Bioengineering BioIRC, Kragujevac, Serbia
- Faculty of Engineering, University of Kragujevac, Kragujevac, Serbia
| | - Z. Milosevic
- Research and Development Center for Bioengineering BioIRC, Kragujevac, Serbia
| | | | - N. Ilic
- Faculty of Medicine, University of Belgrade, Belgrade, Serbia
- Clinic for Vascular and Endovascular Surgery, Clinical Center of Serbia, Belgrade, Serbia
| | - M. Dragas
- Faculty of Medicine, University of Belgrade, Belgrade, Serbia
- Clinic for Vascular and Endovascular Surgery, Clinical Center of Serbia, Belgrade, Serbia
| | - M. Sladojevic
- Clinic for Vascular and Endovascular Surgery, Clinical Center of Serbia, Belgrade, Serbia
| | - M. Markovic
- Faculty of Medicine, University of Belgrade, Belgrade, Serbia
- Clinic for Vascular and Endovascular Surgery, Clinical Center of Serbia, Belgrade, Serbia
| | - A. Vujcic
- Clinic for Vascular and Endovascular Surgery, Clinical Center of Serbia, Belgrade, Serbia
| | - N. Filipovic
- Research and Development Center for Bioengineering BioIRC, Kragujevac, Serbia
- Faculty of Engineering, University of Kragujevac, Kragujevac, Serbia
| | - L. Davidovic
- Faculty of Medicine, University of Belgrade, Belgrade, Serbia
- Clinic for Vascular and Endovascular Surgery, Clinical Center of Serbia, Belgrade, Serbia
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Gasser TC, Miller C, Polzer S, Roy J. A quarter of a century biomechanical rupture risk assessment of abdominal aortic aneurysms. Achievements, clinical relevance, and ongoing developments. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2023; 39:e3587. [PMID: 35347895 DOI: 10.1002/cnm.3587] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 01/28/2022] [Accepted: 03/03/2022] [Indexed: 05/12/2023]
Abstract
Abdominal aortic aneurysm (AAA) disease, the local enlargement of the infrarenal aorta, is a serious condition that causes many deaths, especially in men exceeding 65 years of age. Over the past quarter of a century, computational biomechanical models have been developed towards the assessment of AAA risk of rupture, technology that is now on the verge of being integrated within the clinical decision-making process. The modeling of AAA requires a holistic understanding of the clinical problem, in order to set appropriate modeling assumptions and to draw sound conclusions from the simulation results. In this article we summarize and critically discuss the proposed modeling approaches and report the outcome of clinical validation studies for a number of biomechanics-based rupture risk indices. Whilst most of the aspects concerning computational mechanics have already been settled, it is the exploration of the failure properties of the AAA wall and the acquisition of robust input data for simulations that has the greatest potential for the further improvement of this technology.
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Affiliation(s)
- T Christian Gasser
- Department of Engineering Mechanics, KTH Royal Institute of Technology, Stockholm, Sweden
- Faculty of Health Sciences, University of Southern Denmark, Odense, Denmark
| | - Christopher Miller
- Department of Engineering Mechanics, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Stanislav Polzer
- Department of Applied Mechanics, VSB-Technical University of Ostrava, Ostrava-Poruba, Czech Republic
| | - Joy Roy
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
- Department of Vascular Surgery, Karolinska University Hospital, Stockholm, Sweden
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14
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Chung TK, Gueldner PH, Kickliter TM, Liang NL, Vorp DA. An Objective and Repeatable Sac Isolation Technique for Comparing Biomechanical Metrics in Abdominal Aortic Aneurysms. Bioengineering (Basel) 2022; 9:601. [PMID: 36354512 PMCID: PMC9687639 DOI: 10.3390/bioengineering9110601] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2022] [Revised: 10/09/2022] [Accepted: 10/20/2022] [Indexed: 07/02/2024] Open
Abstract
(1) Abdominal aortic aneurysm (AAA) biomechanics-based metrics often reported may be over/under-estimated by including non-aneurysmal regions in the analyses, which is typical, rather than isolating the dilated sac region. We demonstrate the utility of a novel sac-isolation algorithm by comparing peak/mean wall stress (PWS, MWS), with/without sac isolation, for AAA that were categorized as stable or unstable in 245 patient CT image sets. (2) 245 patient computed tomography images were collected, segmented, meshed, and had subsequent finite element analysis performed in preparation of our novel sac isolation technique. Sac isolation was initiated by rotating 3D surfaces incrementally, extracting 2D projections, curve fitting a Fourier series, and taking the local extrema as superior/inferior boundaries for the aneurysmal sac. The PWS/MWS were compared pairwise using the entire aneurysm and the isolated sac alone. (3) MWS, not PWS, was significantly different between the sac alone and the entire aneurysm. We found no statistically significant difference in wall stress measures between stable (n = 222) and unstable (n = 23) groups using the entire aneurysm. However, using sac-isolation, PWS (24.6 ± 7.06 vs. 20.5 ± 8.04 N/cm2; p = 0.003) and MWS (12.0 ± 3.63 vs. 10.5 ± 4.11 N/cm2; p = 0.022) were both significantly higher in unstable vs. stable groups. (4) Our results suggest that evaluating only the AAA sac can influence wall stress metrics and may reveal differences in stable and unstable groups of aneurysms that may not otherwise be detected when the entire aneurysm is used.
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Affiliation(s)
- Timothy K. Chung
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Pete H. Gueldner
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Trevor M. Kickliter
- Department of Mechanical Engineering and Materials Science, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Nathan L. Liang
- Department of Surgery, University of Pittsburgh, Pittsburgh, PA 15213, USA
- Division of Vascular Surgery, University of Pittsburgh Medical Center, Pittsburgh, PA 15213, USA
| | - David A. Vorp
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15260, USA
- Department of Mechanical Engineering and Materials Science, University of Pittsburgh, Pittsburgh, PA 15261, USA
- Department of Surgery, University of Pittsburgh, Pittsburgh, PA 15213, USA
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA 15219, USA
- Department of Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, PA 15261, USA
- Department of Cardiothoracic Surgery, University of Pittsburgh, Pittsburgh, PA 15213, USA
- Clinical and Translational Sciences Institute, University of Pittsburgh, Pittsburgh, PA 15213, USA
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15
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Singh TP, Moxon JV, Gasser TC, Dalman RL, Bourke M, Bourke B, Tomee SM, Dawson J, Golledge J. Effect of telmisartan on the peak wall stress and peak wall rupture index of small abdominal aortic aneurysms: An exploratory analysis of the TEDY trial. Eur J Vasc Endovasc Surg 2022; 64:396-404. [DOI: 10.1016/j.ejvs.2022.07.042] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 07/16/2022] [Accepted: 07/22/2022] [Indexed: 11/26/2022]
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Ning H, Liu X, Ma C, Yang J, Li T. The Evaluation of Longitudinal Strain of Large and Small Abdominal Aortic Aneurysm by Two-Dimensional Speckle-Tracking Ultrasound. JOURNAL OF ULTRASOUND IN MEDICINE : OFFICIAL JOURNAL OF THE AMERICAN INSTITUTE OF ULTRASOUND IN MEDICINE 2022; 41:1085-1093. [PMID: 34296470 DOI: 10.1002/jum.15792] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 06/21/2021] [Accepted: 07/10/2021] [Indexed: 06/13/2023]
Abstract
OBJECTIVES Abdominal aortic aneurysm (AAA) is a dangerous and lethal vascular disease. Non-invasive two-dimensional speckle-tracking imaging (2D STI) plays an important role in assessing aortic biomechanical properties. Our study aimed to evaluate the alterations of biomechanical characteristics using 2D STI in 91 AAA patients with different size. METHODS Aneurysm strain, elastic modulus, stiffness index β, and aortic distensibility determined by M-Mode ultrasound (US), and longitudinal strain (LS) derived from 2D STI were compared in 40 large AAA patients (diameter ≥ 55 mm) and 51 small AAA patients (diameter < 55 mm). RESULTS Compared with small AAA group, anterior wall longitudinal strain (ALS) and posterior wall longitudinal strain (PLS) were significantly decreased in large AAA group (all P < .05) and not affected by age, symptom, hypertension, and thrombus. Meanwhile, ALS and PLS correlated negatively with maximal aneurysm diameters (r = -0.628 and -0.469, respectively, all P < .001). And only ALS was associated with M-Mode US parameters (all P < .05). Based on receiver operating characteristic (ROC) analysis, ALS and PLS had strong diagnostic values for large AAA with the area under the curve (AUC) of 0.82 and 0.72, and cut-off points of 1.71 and 1.64% with a sensitivity of 78 and 72%, and a specificity of 75 and 70%, respectively. CONCLUSIONS LS measured by 2D STI could evaluate the biomechanical properties of aneurysm wall with different size, and add additional diagnostic value in distinguishing between small and large AAA.
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Affiliation(s)
- Hongxia Ning
- Department of Cardiovascular Ultrasound, The First Hospital of China Medical University, Shenyang, Liaoning Province, China
| | - Xiaozheng Liu
- Department of Cardiovascular Ultrasound, The First Hospital of China Medical University, Shenyang, Liaoning Province, China
| | - Chunyan Ma
- Department of Cardiovascular Ultrasound, The First Hospital of China Medical University, Shenyang, Liaoning Province, China
| | - Jun Yang
- Department of Cardiovascular Ultrasound, The First Hospital of China Medical University, Shenyang, Liaoning Province, China
| | - Tan Li
- Department of Cardiovascular Ultrasound, The First Hospital of China Medical University, Shenyang, Liaoning Province, China
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Zhang W, Sommer G, Niestrawska JA, Holzapfel GA, Nordsletten D. The effects of viscoelasticity on residual strain in aortic soft tissues. Acta Biomater 2022; 140:398-411. [PMID: 34823042 DOI: 10.1016/j.actbio.2021.11.019] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 11/14/2021] [Accepted: 11/15/2021] [Indexed: 11/15/2022]
Abstract
Residual stress is thought to play a critical role in modulating stress distributions in soft biological tissues and in maintaining the mechanobiological stress environment of cells. Residual stresses in arteries and other tissues are classically assessed through opening angle experiments, which demonstrate the continuous release of residual stresses over hours. These results are then assessed through nonlinear biomechanical models to provide estimates of the residual stresses in the intact state. Although well studied, these analyses typically focus on hyperelastic material models despite significant evidence of viscoelastic phenomena over both short and long timescales. In this work, we extended the state-of-the-art structural tensor model for arterial tissues from Holzapfel and Ogden for fractional viscoelasticity. Models were tuned to capture consistent levels of hysteresis observed in biaxial experiments, while also minimizing the fractional viscoelastic weighting and opening angles to correctly capture opening angle dynamics. Results suggest that a substantial portion of the human abdominal aorta is viscoelastic, but exhibits a low fractional order (i.e. more elastically). Additionally, a significantly larger opening angle in the fully unloaded state is necessary to produce comparable hysteresis in biaxial testing. As a consequence, conventional estimates of residual stress using hyperelastic approaches over-estimate their viscoelastic counterparts by a factor of 2. Thus, a viscoelastic approach, such as the one illustrated in this study, in combination with an additional source of rate-controlled viscoelastic data is necessary to accurately analyze the residual stress distribution in soft biological tissues. STATEMENT OF SIGNIFICANCE: Residual stress plays a crucial role in achieving a homeostatic stress environment in soft biological tissues. However, the analysis of residual stress typically focuses on hyperelastic material models despite evidence of viscoelastic behavior. This work is the first attempt at analyzing the effects of viscoelasticity on residual stress. The application of viscoelasticity was crucial for producing realistic opening dynamics in arteries. The overall residual stresses were estimated to be 50% less than those from using hyperelastic material models, while the opening angles were projected to be 25% more than those measured after 16 hours, suggesting underestimated residual strain. This study highlights the importance viscoelasticity in the analysis of residual stress even in weakly dissipative materials like the human aorta.
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Affiliation(s)
- Will Zhang
- Department of Biomedical Engineering, University of Michigan, North Campus Research Center, Building 20, 2800 Plymouth Rd, Ann Arbor 48109, USA.
| | - Gerhard Sommer
- Institute of Biomechanics, Graz University of Technology, AT, Austria
| | - Justyna A Niestrawska
- Gottfried Schatz Research Center, Division of Macroscopic and Clinical Anatomy, Medical University of Graz, Harrachgasse 21, 8010 Graz, Austria
| | - Gerhard A Holzapfel
- Institute of Biomechanics, Graz University of Technology, AT, Austria; Department of Structural Engineering, Norwegian University of Science and Technology, Trondheim, NO, Norway
| | - David Nordsletten
- Division of Biomedical Engineering and Imaging Sciences, Department of Biomedical Engineering, King's College London, UK; Departments of Biomedical Engineering and Cardiac Surgery, University of Michigan, Ann Arbor, USA
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Lindquist Liljeqvist M, Bogdanovic M, Siika A, Gasser TC, Hultgren R, Roy J. Geometric and biomechanical modeling aided by machine learning improves the prediction of growth and rupture of small abdominal aortic aneurysms. Sci Rep 2021; 11:18040. [PMID: 34508118 PMCID: PMC8433325 DOI: 10.1038/s41598-021-96512-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Accepted: 08/02/2021] [Indexed: 12/17/2022] Open
Abstract
It remains difficult to predict when which patients with abdominal aortic aneurysm (AAA) will require surgery. The aim was to study the accuracy of geometric and biomechanical analysis of small AAAs to predict reaching the threshold for surgery, diameter growth rate and rupture or symptomatic aneurysm. 189 patients with AAAs of diameters 40-50 mm were included, 161 had undergone two CTAs. Geometric and biomechanical variables were used in prediction modelling. Classifications were evaluated with area under receiver operating characteristic curve (AUC) and regressions with correlation between observed and predicted growth rates. Compared with the baseline clinical diameter, geometric-biomechanical analysis improved prediction of reaching surgical threshold within four years (AUC 0.80 vs 0.85, p = 0.031) and prediction of diameter growth rate (r = 0.17 vs r = 0.38, p = 0.0031), mainly due to the addition of semiautomatic diameter measurements. There was a trend towards increased precision of volume growth rate prediction (r = 0.37 vs r = 0.45, p = 0.081). Lumen diameter and biomechanical indices were the only variables that could predict future rupture or symptomatic AAA (AUCs 0.65-0.67). Enhanced precision of diameter measurements improves the prediction of reaching the surgical threshold and diameter growth rate, while lumen diameter and biomechanical analysis predicts rupture or symptomatic AAA.
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Affiliation(s)
- Moritz Lindquist Liljeqvist
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden.
- Department of Vascular Surgery, Karolinska University Hospital, Stockholm, Sweden.
| | - Marko Bogdanovic
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
| | - Antti Siika
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
| | - T Christian Gasser
- Department of Engineering Mechanics, Royal Institute of Technology, Stockholm, Sweden
| | - Rebecka Hultgren
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
- Department of Vascular Surgery, Karolinska University Hospital, Stockholm, Sweden
| | - Joy Roy
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
- Department of Vascular Surgery, Karolinska University Hospital, Stockholm, Sweden
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Lorenzen US, Eiberg JP, Hultgren R, Wanhainen A, Langenskiöld M, Sillesen HH, Bredahl KK. The Short-term Predictive Value of Vessel Wall Stiffness on Abdominal Aortic Aneurysm Growth. Ann Vasc Surg 2021; 77:187-194. [PMID: 34437978 DOI: 10.1016/j.avsg.2021.05.051] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 05/14/2021] [Accepted: 05/16/2021] [Indexed: 12/20/2022]
Abstract
BACKGROUND Abdominal aortic aneurysm (AAA) surveillance programs are currently based solely on AAA diameter. The diameter criterion alone, however, seems inadequate as small AAAs comprise 5-10 % of ruptured AAAs as well as some large AAAs never rupture. Aneurysm wall stiffness has been suggested to predict rupture and growth; this study aimed to investigate the prognostic value of AAA vessel wall stiffness for growth on prospectively collected data. METHODS Analysis was based on data from a randomised, placebo-controlled, multicentre trial investigating mast-cell-inhibitors to halt aneurysm growth (the AORTA trial). Systolic and diastolic AAA diameter was determined in 326 patients using electrocardiogram-gated ultrasound (US). Stiffness was calculated at baseline and after 1 year. RESULTS Maximum AAA diameter increased from 44.1 mm to 46.5 mm during the study period. Aneurysm growth after 1 year was not predicted by baseline stiffness (-0.003 mm/U; 95 % CI: -0.007 to 0.001 mm/U; P = 0.15). Throughout the study period, stiffness remained unchanged (8.3 U; 95 % CI: -2.5 to 19.1 U; P = 0.13) and without significant correlation to aneurysm growth (R: 0.053; P = 0.38). CONCLUSIONS Following a rigorous US protocol, this study could not confirm AAA vessel wall stiffness as a predictor of aneurysm growth in a 1-year follow-up design. The need for new and subtle methods to complement diameter for improved AAA risk assessment is warranted.
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Affiliation(s)
| | - Jonas P Eiberg
- Department of Vascular Surgery, Rigshospitalet, Denmark; Copenhagen Academy for Medical Education and Simulation (CAMES), Capital Region of Denmark, Copenhagen, Denmark; Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Rebecka Hultgren
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Sweden; Department of Vascular Surgery, Karolinska University Hospital, Stockholm, Sweden
| | - Anders Wanhainen
- Department of Surgical Sciences, Vascular Surgery, Uppsala University, Sweden
| | - Marcus Langenskiöld
- Department of Molecular and Clinical Medicine, University of Gothenurg, Sweden
| | - Henrik H Sillesen
- Department of Vascular Surgery, Rigshospitalet, Denmark; Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Kim K Bredahl
- Department of Vascular Surgery, Rigshospitalet, Denmark; Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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20
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Singh TP, Moxon JV, Iyer V, Gasser TC, Jenkins J, Golledge J. Comparison of peak wall stress and peak wall rupture index in ruptured and asymptomatic intact abdominal aortic aneurysms. Br J Surg 2021; 108:652-658. [PMID: 34157087 DOI: 10.1002/bjs.11995] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2020] [Revised: 07/01/2020] [Accepted: 07/22/2020] [Indexed: 11/10/2022]
Abstract
BACKGROUND Previous studies have suggested that finite element analysis (FEA) can estimate the rupture risk of an abdominal aortic aneurysm (AAA); however, the value of biomechanical estimates over measurement of AAA diameter alone remains unclear. This study aimed to compare peak wall stress (PWS) and peak wall rupture index (PWRI) in participants with ruptured and asymptomatic intact AAAs. METHODS The reproducibility of semiautomated methods for estimating aortic PWS and PWRI from CT images was assessed. PWS and PWRI were estimated in people with ruptured AAAs and those with asymptomatic intact AAAs matched by orthogonal diameter on a 1 : 2 basis. Spearman's correlation coefficient was used to assess the association between PWS or PWRI and AAA diameter. Independent associations between PWS or PWRI and AAA rupture were identified by means of logistic regression analyses. RESULTS Twenty individuals were included in the analysis of reproducibility. The main analysis included 50 patients with an intact AAA and 25 with a ruptured AAA. Median orthogonal diameter was similar in ruptured and intact AAAs (82·3 (i.q.r. 73·5-92·0) versus 81·0 (73·2-92·4) mm respectively; P = 0·906). Median PWS values were 286·8 (220·2-329·6) and 245·8 (215·2-302·3) kPa respectively (P = 0·192). There was no significant difference in PWRI between the two groups (P = 0·982). PWS and PWRI correlated positively with orthogonal diameter (both P < 0·001). Participants with high PWS, but not PWRI, were more likely to have a ruptured AAA after adjusting for potential confounders (odds ratio 5·84, 95 per cent c.i. 1·22 to 27·95; P = 0·027). This association was not maintained in all sensitivity analyses. CONCLUSION High aortic PWS had an inconsistent association with greater odds of aneurysm rupture in patients with a large AAA.
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Affiliation(s)
- T P Singh
- Queensland Research Centre for Peripheral Vascular Disease, College of Medicine and Dentistry, Townsville, Australia
- Department of Vascular and Endovascular Surgery, Townsville University Hospital, Townsville, Australia
| | - J V Moxon
- Queensland Research Centre for Peripheral Vascular Disease, College of Medicine and Dentistry, Townsville, Australia
- Australian Institute of Tropical Health and Medicine, James Cook University, Townsville, Australia
| | - V Iyer
- Queensland Research Centre for Peripheral Vascular Disease, College of Medicine and Dentistry, Townsville, Australia
- Department of Vascular and Endovascular Surgery, Townsville University Hospital, Townsville, Australia
- Department of Vascular and Endovascular Surgery, Royal Brisbane and Women's Hospital Brisbane Queensland Australia
| | - T C Gasser
- KTH Solid Mechanics, Department of Engineering Mechanics, KTH Royal Institute of Technology, Stockholm, Sweden
| | - J Jenkins
- Department of Vascular and Endovascular Surgery, Royal Brisbane and Women's Hospital Brisbane Queensland Australia
| | - J Golledge
- Queensland Research Centre for Peripheral Vascular Disease, College of Medicine and Dentistry, Townsville, Australia
- Australian Institute of Tropical Health and Medicine, James Cook University, Townsville, Australia
- Department of Vascular and Endovascular Surgery, Townsville University Hospital, Townsville, Australia
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Doyle BJ, Bappoo N, Syed MB, Forsythe RO, Powell JT, Conlisk N, Hoskins PR, McBride OM, Shah AS, Norman PE, Newby DE. Biomechanical Assessment Predicts Aneurysm Related Events in Patients with Abdominal Aortic Aneurysm. Eur J Vasc Endovasc Surg 2020; 60:365-373. [DOI: 10.1016/j.ejvs.2020.02.023] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Revised: 02/04/2020] [Accepted: 02/26/2020] [Indexed: 01/09/2023]
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Miller K, Mufty H, Catlin A, Rogers C, Saunders B, Sciarrone R, Fourneau I, Meuris B, Tavner A, Joldes GR, Wittek A. Is There a Relationship Between Stress in Walls of Abdominal Aortic Aneurysm and Symptoms? J Surg Res 2020; 252:37-46. [DOI: 10.1016/j.jss.2020.01.025] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2019] [Revised: 01/17/2020] [Accepted: 01/31/2020] [Indexed: 10/24/2022]
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Predictors of Abdominal Aortic Aneurysm Risks. Bioengineering (Basel) 2020; 7:bioengineering7030079. [PMID: 32707846 PMCID: PMC7552640 DOI: 10.3390/bioengineering7030079] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 07/17/2020] [Accepted: 07/20/2020] [Indexed: 11/16/2022] Open
Abstract
Computational biomechanics via finite element analysis (FEA) has long promised a means of assessing patient-specific abdominal aortic aneurysm (AAA) rupture risk with greater efficacy than current clinically used size-based criteria. The pursuit stems from the notion that AAA rupture occurs when wall stress exceeds wall strength. Quantification of peak (maximum) wall stress (PWS) has been at the cornerstone of this research, with numerous studies having demonstrated that PWS better differentiates ruptured AAAs from non-ruptured AAAs. In contrast to wall stress models, which have become progressively more sophisticated, there has been relatively little progress in estimating patient-specific wall strength. This is because wall strength cannot be inferred non-invasively, and measurements from excised patient tissues show a large spectrum of wall strength values. In this review, we highlight studies that investigated the relationship between biomechanics and AAA rupture risk. We conclude that combining wall stress and wall strength approximations should provide better estimations of AAA rupture risk. However, before personalized biomechanical AAA risk assessment can become a reality, better methods for estimating patient-specific wall properties or surrogate markers of aortic wall degradation are needed. Artificial intelligence methods can be key in stratifying patients, leading to personalized AAA risk assessment.
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Canchi T, Patnaik SS, Nguyen HN, Ng EYK, Narayanan S, Muluk SC, De Oliveira V, Finol EA. A Comparative Study of Biomechanical and Geometrical Attributes of Abdominal Aortic Aneurysms in the Asian and Caucasian Populations. J Biomech Eng 2020; 142:061003. [PMID: 31633169 PMCID: PMC10782868 DOI: 10.1115/1.4045268] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2019] [Revised: 09/24/2019] [Indexed: 11/08/2022]
Abstract
In this work, we provide a quantitative assessment of the biomechanical and geometric features that characterize abdominal aortic aneurysm (AAA) models generated from 19 Asian and 19 Caucasian diameter-matched AAA patients. 3D patient-specific finite element models were generated and used to compute peak wall stress (PWS), 99th percentile wall stress (99th WS), and spatially averaged wall stress (AWS) for each AAA. In addition, 51 global geometric indices were calculated, which quantify the wall thickness, shape, and curvature of each AAA. The indices were correlated with 99th WS (the only biomechanical metric that exhibited significant association with geometric indices) using Spearman's correlation and subsequently with multivariate linear regression using backward elimination. For the Asian AAA group, 99th WS was highly correlated (R2 = 0.77) with three geometric indices, namely tortuosity, intraluminal thrombus volume, and area-averaged Gaussian curvature. Similarly, 99th WS in the Caucasian AAA group was highly correlated (R2 = 0.87) with six geometric indices, namely maximum AAA diameter, distal neck diameter, diameter-height ratio, minimum wall thickness variance, mode of the wall thickness variance, and area-averaged Gaussian curvature. Significant differences were found between the two groups for ten geometric indices; however, no differences were found for any of their respective biomechanical attributes. Assuming maximum AAA diameter as the most predictive metric for wall stress was found to be imprecise: 24% and 28% accuracy for the Asian and Caucasian groups, respectively. This investigation reveals that geometric indices other than maximum AAA diameter can serve as predictors of wall stress, and potentially for assessment of aneurysm rupture risk, in the Asian and Caucasian AAA populations.
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Affiliation(s)
- Tejas Canchi
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore 639798
| | - Sourav S. Patnaik
- Department of Mechanical Engineering, University of Texas at San Antonio, San Antonio, TX 78249
| | - Hong N. Nguyen
- Department of Biomedical Engineering, University of Texas at San Antonio, San Antonio, TX 78249
| | - E. Y. K. Ng
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore 639798
| | - Sriram Narayanan
- The Harley Street Heart and Vascular Centre, Gleneagles Hospital, Singapore 258500
| | - Satish C. Muluk
- Department of Thoracic & Cardiovascular Surgery, Allegheny Health Network, Pittsburgh, PA 15212
| | - Victor De Oliveira
- Department of Management and Statistics, University of Texas at San Antonio, San Antonio, TX 78249
| | - Ender A. Finol
- Department of Mechanical Engineering, University of Texas at San Antonio, One UTSA Circle, EB 3.04.08, San Antonio, TX 78249
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Hultgren R, Elfström KM, Öhman D, Linné A. Long-Term Follow-Up of Men Invited to Participate in a Population-Based Abdominal Aortic Aneurysm Screening Program. Angiology 2020; 71:641-649. [PMID: 32351123 DOI: 10.1177/0003319720921741] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
A screening program for abdominal aortic aneurysm (AAA), inviting 65-year-old men, was started in Stockholm in 2010 (2.3 million inhabitants). The aim was to present a long-term follow-up of men participating in screening, as well as AAA repair and ruptures among nonparticipants. Demographics were collected for men with screening detected with AAA 2010 to 2016 (n = 672) and a control group with normal aortas at screening (controls, n = 237). Medical charts and regional Swedvasc (Swedish Vascular registry) data were analyzed for aortic repair for men born 1945 to 1951. Ultrasound maximum aortic diameter (AD) as well as Aortic Size Index (ASI) was recorded. Participation was 78% and prevalence of AAA was 1.2% (n = 672). Aortic repair rates correlated with high ASI and AD. During the study period, 22% of the AAA patients were treated with the elective repair; 35 men in surveillance died (5.2%), non-AAA-related causes (82.9%) dominated, followed by unknown causes among 4 (11.4%), and 2 (5.7%) possibly AAA-related deaths. Abdominal aortic aneurysm rupture rate was higher among nonparticipants (0.096% vs 0.0036%, P < .001). The low dropout rate confirms acceptability of follow-up after screening. The efficacy is shown by the much higher rupture rate among the nonparticipating men.
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Affiliation(s)
- Rebecka Hultgren
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden.,Department of Vascular Surgery, Karolinska University Hospital, Stockholm, Sweden
| | | | - Daniel Öhman
- Regional Cancer Center Stockholm-Gotland, Stockholm, Sweden
| | - Anneli Linné
- Department of Clinical Science and Education, Karolinska Institutet at Södersjukhuset, Stockholm, Sweden.,Department of Surgery, Section of Vascular Surgery, Södersjukhuset, Stockholm, Sweden
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26
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Zhang W, Capilnasiu A, Sommer G, Holzapfel GA, Nordsletten DA. An efficient and accurate method for modeling nonlinear fractional viscoelastic biomaterials. COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING 2020; 362:112834. [PMID: 34136022 PMCID: PMC7610983 DOI: 10.1016/j.cma.2020.112834] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Computational biomechanics plays an important role in biomedical engineering: using modeling to understand pathophysiology, treatment and device design. While experimental evidence indicates that the mechanical response of most tissues is viscoelastic, current biomechanical models in the computational community often assume hyperelastic material models. Fractional viscoelastic constitutive models have been successfully used in literature to capture viscoelastic material response; however, the translation of these models into computational platforms remains limited. Many experimentally derived viscoelastic constitutive models are not suitable for three-dimensional simulations. Furthermore, the use of fractional derivatives can be computationally prohibitive, with a number of current numerical approximations having a computational cost that is 𝒪 ( N T 2 ) and a storage cost that is 𝒪(NT ) (NT denotes the number of time steps). In this paper, we present a novel numerical approximation to the Caputo derivative which exploits a recurrence relation similar to those used to discretize classic temporal derivatives, giving a computational cost that is 𝒪(NT ) and a storage cost that is fixed over time. The approximation is optimized for numerical applications, and an error estimate is presented to demonstrate the efficacy of the method. The method, integrated into a finite element solid mechanics framework, is shown to be unconditionally stable in the linear viscoelastic case. It was then integrated into a computational biomechanical framework, with several numerical examples verifying the accuracy and computational efficiency of the method, including in an analytic test, in an analytic fractional differential equation, as well as in a computational biomechanical model problem.
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Affiliation(s)
- Will Zhang
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, USA
| | - Adela Capilnasiu
- School of Biomedical Engineering and Imaging Sciences, King’s College London, London, UK
| | - Gerhard Sommer
- Institute of Biomechanics, Graz University of Technology, AT, Austria
| | - Gerhard A. Holzapfel
- Institute of Biomechanics, Graz University of Technology, AT, Austria
- Department of Structural Engineering, Norwegian University of Science and Technology, Trondheim, NO, Norway
| | - David A. Nordsletten
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, USA
- Department of Cardiac Surgery, University of Michigan, Ann Arbor, USA
- School of Biomedical Engineering and Imaging Sciences, King’s College London, London, UK
- Corresponding author at: B20 212W, NCRC, 2800 Plymouth Rd, Ann Arbor, MI, USA, 48109. (D.A. Nordsletten)
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27
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Reproducibility assessment of ultrasound-based aortic stiffness quantification and verification using Bi-axial tensile testing. J Mech Behav Biomed Mater 2020; 103:103571. [DOI: 10.1016/j.jmbbm.2019.103571] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Revised: 09/10/2019] [Accepted: 11/29/2019] [Indexed: 01/04/2023]
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28
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van Disseldorp EM, van Dronkelaar JJ, Pluim JP, van de Vosse FN, van Sambeek MR, Lopata RG. Ultrasound Based Wall Stress Analysis of Abdominal Aortic Aneurysms using Multiperspective Imaging. Eur J Vasc Endovasc Surg 2020; 59:81-91. [DOI: 10.1016/j.ejvs.2019.01.026] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Accepted: 01/22/2019] [Indexed: 12/27/2022]
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29
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Estimation of Abdominal Aortic Aneurysm Rupture Risk with Biomechanical Imaging Markers. J Vasc Interv Radiol 2019; 30:987-994.e4. [PMID: 31109852 DOI: 10.1016/j.jvir.2019.01.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Revised: 12/30/2018] [Accepted: 01/13/2019] [Indexed: 11/22/2022] Open
Abstract
PURPOSE To evaluate whether the biomechanical marker known as rupture risk equivalent diameter (RRED) was superior to the actual abdominal aortic aneurysm (AAA) diameter in estimating future rupture risk in patients who had undergone pre-rupture computed tomography (CT) angiography. MATERIALS AND METHODS A retrospective study was conducted in 13 patients with ruptured AAAs who had undergone CT angiography before and after rupture between 2001 and 2015. The median time between the 2 scans was 731 days. Biomechanical and geometrical markers such as maximal AAA diameter, peak wall stress (PWS), and RRED were calculated with AAA-dedicated software. The main analyses determined whether RRED was higher than the actual diameter and the threshold diameter for elective surgery (55 mm for men, 50 mm for women) in AAAs before and after rupture. Differences between diameter and biomechanical markers before and after rupture were tested with appropriate statistical tests. RESULTS RRED before and after rupture was smaller than the actual diameter in 7 of 13 cases. Post-rupture RRED was estimated to be smaller than the threshold diameter for elective repair in 4 cases, again suggesting a low rupture risk. The median PWS before and after rupture was 181.7 kPa (interquartile range [IQR], 152.1-244.2 kPa) and 274.1 kPa (IQR, 172.2-377.2 kPa), respectively. CONCLUSIONS RRED was smaller than the actual diameter in more than half of pre-rupture AAAs, suggesting a lower rupture risk than estimated with the actual diameter. The results suggest that the currently available biomechanical imaging markers might not be ready for use in clinical practice.
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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: 0.8] [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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Siika A, Lindquist Liljeqvist M, Hultgren R, Gasser TC, Roy J. Aortic Lumen Area Is Increased in Ruptured Abdominal Aortic Aneurysms and Correlates to Biomechanical Rupture Risk. J Endovasc Ther 2018; 25:750-756. [PMID: 30354931 DOI: 10.1177/1526602818808292] [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] [Indexed: 11/16/2022]
Abstract
PURPOSE To investigate how 2-dimensional geometric parameters differ between ruptured and asymptomatic abdominal aortic aneurysms (AAAs) and provide a biomechanical explanation for the findings. METHODS The computed tomography angiography (CTA) scans of 30 patients (mean age 77±10 years; 23 men) with ruptured AAAs and 60 patients (mean age 76±8 years; 46 men) with asymptomatic AAAs were used to measure maximum sac diameter along the center lumen line, the cross-sectional lumen area, the total vessel area, the intraluminal thrombus (ILT) area, and corresponding volumes. The CTA data were segmented to create 3-dimensional patient-specific models for finite element analysis to compute peak wall stress (PWS) and the peak wall rupture index (PWRI). To reduce confounding from the maximum diameter, 2 diameter-matched groups were selected from the initial patient cohorts: 28 ruptured AAAs and another with 15 intact AAAs (diameters 74±12 vs 73±11, p=0.67). A multivariate model including the maximum diameter, the lumen area, and the ILT area of the 60 intact aneurysms was employed to predict biomechanical rupture risk parameters. RESULTS In the diameter-matched subgroup comparison, ruptured AAAs had a significantly larger cross-sectional lumen area (1954±1254 vs 1120±623 mm2, p=0.023) and lower ILT area ratio (55±24 vs 68±24, p=0.037). The ILT area (2836±1462 vs 2385±1364 mm2, p=0.282) and the total vessel area (3956±1170 vs 4338±1388 mm2, p=0.384) did not differ statistically between ruptured and intact aneurysms. The PWRI was increased in ruptured AAAs (0.80 vs 0.48, p<0.001), but the PWS was similar (249 vs 284 kPa, p=0.194). In multivariate regression analysis, lumen area was significantly positively associated with both PWS (p<0.001) and PWRI (p<0.01). The ILT area was also significantly positively associated with PWS (p<0.001) but only weakly with PWRI (p<0.01). The lumen area conferred a higher risk increase in both PWS and PWRI when compared with the ILT area. CONCLUSION The lumen area is increased in ruptured AAAs compared to diameter-matched asymptomatic AAAs. Furthermore, this finding may in part be explained by a relationship with biomechanical rupture risk parameters, in which lumen area, irrespective of maximum diameter, increases PWS and PWRI. These observations thus suggest a possible method to improve prediction of rupture risk in AAAs by measuring the lumen area without the use of computational modeling.
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Affiliation(s)
- Antti Siika
- 1 Department of Molecular Medicine and Surgery, Karolinska Institute, Stockholm, Sweden
| | | | - Rebecka Hultgren
- 1 Department of Molecular Medicine and Surgery, Karolinska Institute, Stockholm, Sweden.,2 Department of Vascular Surgery, Karolinska University Hospital, Stockholm, Sweden
| | - T Christian Gasser
- 3 Department of Solid Mechanics, School of Engineering Sciences, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Joy Roy
- 1 Department of Molecular Medicine and Surgery, Karolinska Institute, Stockholm, Sweden.,2 Department of Vascular Surgery, Karolinska University Hospital, Stockholm, Sweden
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Leemans EL, Willems TP, Slump CH, van der Laan MJ, Zeebregts CJ. Additional value of biomechanical indices based on CTa for rupture risk assessment of abdominal aortic aneurysms. PLoS One 2018; 13:e0202672. [PMID: 30133522 PMCID: PMC6105024 DOI: 10.1371/journal.pone.0202672] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Accepted: 08/07/2018] [Indexed: 11/18/2022] Open
Abstract
OBJECTIVE Biomechanics for rupture risk prediction in abdominal aortic aneurysms (AAA) are gaining popularity. However, their clinical applicability is still doubtful as there is lack of standardization. This study evaluates the added value of biomechanical indices in rupture risk assessment. METHODS This study included 175 asymptomatic, 11 sAAA and 45 ruptured aneurysms. 3D-geometries were reconstructed using computer tomography angiographies. Subsequently, finite element models were made to calculate peak wall stress (PWS), peak wall rupture index (PWRI) and the rupture risk equivalent diameter (RRED). The indices were determined with a dedicated software to facilitate standardization. RESULTS SAAAs showed a trend towards higher PWS, PWRI and RRED compared to asymptomatic AAAs, but PWS (22.0±5.8 vs. 33.4±15.8 N/cm2), PWRI (0.52±0.2 vs. 1.01±0.64), and RRED (65±60 vs. 98±51 mm) were significantly (p = 0.001) higher in ruptured. However, after diameter-matching no significant differences were seen. The ROC-curves for the maximum diameter and all biomechanical indices were similar but it slightly increased when diameter and biomechanical indices were combined. CONCLUSIONS This study showed no added value for biomechanical indices in AAA rupture risk assessment. Additionally, the difficulty of such an assessment increases. However, as symptomatic aneurysms show a trend towards higher biomechanical indices with similar diameters the indices may provide information about aneurysm growth and development.
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Affiliation(s)
- Eva L. Leemans
- Departments of Surgery (Division of Vascular Surgery), University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
- Departments of Biomechanical Engineering and Physics, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
- Radiology, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
- Department of Robotics and Mechatronics, MIRA Institute for Biomedical Engineering and Technical Medicine, University of Twente, Enschede, The Netherlands
| | - Tineke P. Willems
- Radiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Cornelis H. Slump
- Department of Robotics and Mechatronics, MIRA Institute for Biomedical Engineering and Technical Medicine, University of Twente, Enschede, The Netherlands
| | - Maarten J. van der Laan
- Departments of Surgery (Division of Vascular Surgery), University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Clark J. Zeebregts
- Departments of Surgery (Division of Vascular Surgery), University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
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Groeneveld ME, Meekel JP, Rubinstein SM, Merkestein LR, Tangelder GJ, Wisselink W, Truijers M, Yeung KK. Systematic Review of Circulating, Biomechanical, and Genetic Markers for the Prediction of Abdominal Aortic Aneurysm Growth and Rupture. J Am Heart Assoc 2018; 7:JAHA.117.007791. [PMID: 29960996 PMCID: PMC6064909 DOI: 10.1161/jaha.117.007791] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
BACKGROUND The natural course of abdominal aortic aneurysms (AAA) is growth and rupture if left untreated. Numerous markers have been investigated; however, none are broadly acknowledged. Our aim was to identify potential prognostic markers for AAA growth and rupture. METHODS AND RESULTS Potential circulating, biomechanical, and genetic markers were studied. A comprehensive search was conducted in PubMed, Embase, and Cochrane Library in February 2017, following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Study selection, data extraction, and methodological quality assessment were conducted by 2 independent researchers. Plausibility of markers was based on the amount of publications regarding the marker (more than 3), pooled sample size (more than 100), bias risk and statistical significance of the studies. Eighty-two studies were included, which examined circulating (n=40), biomechanical (n=27), and genetic markers (n=7) and combinations of markers (n=8). Factors with an increased expansion risk included: AAA diameter (9 studies; n=1938; low bias risk), chlamydophila pneumonia (4 studies; n=311; medium bias risk), S-elastin peptides (3 studies; n=205; medium bias risk), fluorodeoxyglucose uptake (3 studies; n=104; medium bias risk), and intraluminal thrombus size (5 studies; n=758; medium bias risk). Factors with an increased rupture risk rupture included: peak wall stress (9 studies; n=579; medium bias risk) and AAA diameter (8 studies; n=354; medium bias risk). No meta-analysis was conducted because of clinical and methodological heterogeneity. CONCLUSIONS We identified 5 potential markers with a prognostic value for AAA growth and 2 for rupture. While interpreting these data, one must realize that conclusions are based on small sample sizes and clinical and methodological heterogeneity. Prospective and methodological consonant studies are strongly urged to further study these potential markers.
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Affiliation(s)
- Menno E Groeneveld
- Department of Vascular Surgery, Amsterdam Cardiovascular Sciences (ACS), VU University Medical Center (VUmc), Amsterdam, The Netherlands.,Department of Physiology, Amsterdam Cardiovascular Sciences (ACS), VU University Medical Center (VUmc), Amsterdam, The Netherlands
| | - Jorn P Meekel
- Department of Vascular Surgery, Amsterdam Cardiovascular Sciences (ACS), VU University Medical Center (VUmc), Amsterdam, The Netherlands.,Department of Physiology, Amsterdam Cardiovascular Sciences (ACS), VU University Medical Center (VUmc), Amsterdam, The Netherlands
| | - Sidney M Rubinstein
- Department of Health Sciences and Amsterdam Public Health research institute, VU University, Amsterdam, The Netherlands
| | - Lisanne R Merkestein
- Department of Vascular Surgery, Amsterdam Cardiovascular Sciences (ACS), VU University Medical Center (VUmc), Amsterdam, The Netherlands
| | - Geert Jan Tangelder
- Department of Physiology, Amsterdam Cardiovascular Sciences (ACS), VU University Medical Center (VUmc), Amsterdam, The Netherlands
| | - Willem Wisselink
- Department of Vascular Surgery, Amsterdam Cardiovascular Sciences (ACS), VU University Medical Center (VUmc), Amsterdam, The Netherlands
| | - Maarten Truijers
- Department of Vascular Surgery, Amsterdam Cardiovascular Sciences (ACS), VU University Medical Center (VUmc), Amsterdam, The Netherlands
| | - Kak Khee Yeung
- Department of Vascular Surgery, Amsterdam Cardiovascular Sciences (ACS), VU University Medical Center (VUmc), Amsterdam, The Netherlands .,Department of Physiology, Amsterdam Cardiovascular Sciences (ACS), VU University Medical Center (VUmc), Amsterdam, The Netherlands
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Abstract
Abdominal aortic aneurysm (AAA) is most commonly defined as a maximal diameter of the abdominal aorta in excess of 3 cm in either anterior-posterior or transverse planes or, alternatively, as a focal dilation ≥ 1.5 times the diameter of the normal adjacent arterial segment. Risk factors for the development of AAA include age > 60, tobacco use, male gender, Caucasian race, and family history of AAA. Aneurysm growth and rupture risk appear to be associated with persistent tobacco use, female gender, and chronic pulmonary disease. The majority of AAAs are asymptomatic and detected incidentally on various imaging studies, including abdominal ultrasound, and computed tomographic angiography. Symptoms associated with AAA may include abdominal or back pain, thromboembolization, atheroembolization, aortic rupture, or development of an arteriovenous or aortoenteric fistula. The Screening Abdominal Aortic Aneurysms Efficiently (SAAAVE) Act provides coverage for a one-time screening abdominal ultrasound at age 65 for men who have smoked at least 100 cigarettes and women who have family history of AAA disease. Medical management is recommended for asymptomatic patients with AAAs < 5 cm in diameter and focuses on modifiable risk factors, including smoking cessation and blood pressure control. Primary indications for intervention in patients with AAA include development of symptoms, rupture, rapid aneurysm growth (> 5 mm/6 months), or presence of a fusiform aneurysm with maximum diameter of 5.5 cm or greater. Intervention for AAA includes conventional open surgical repair and endovascular aortic stent graft repair.
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van Disseldorp EMJ, Petterson NJ, van de Vosse FN, van Sambeek MRHM, Lopata RGP. Quantification of aortic stiffness and wall stress in healthy volunteers and abdominal aortic aneurysm patients using time-resolved 3D ultrasound: a comparison study. Eur Heart J Cardiovasc Imaging 2018; 20:185-191. [DOI: 10.1093/ehjci/jey051] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Accepted: 03/12/2018] [Indexed: 01/29/2023] Open
Affiliation(s)
- Emiel M J van Disseldorp
- Cardiovascular Biomechanics Group, Department of Biomedical Engineering, Eindhoven University of Technology, P.O. Box 513, MB Eindhoven, The Netherlands
- Department of Surgery, Catharina Hospital Eindhoven, ZA Eindhoven, The Netherlands
| | - Niels J Petterson
- Cardiovascular Biomechanics Group, Department of Biomedical Engineering, Eindhoven University of Technology, P.O. Box 513, MB Eindhoven, The Netherlands
| | - Frans N van de Vosse
- Cardiovascular Biomechanics Group, Department of Biomedical Engineering, Eindhoven University of Technology, P.O. Box 513, MB Eindhoven, The Netherlands
| | - Marc R H M van Sambeek
- Cardiovascular Biomechanics Group, Department of Biomedical Engineering, Eindhoven University of Technology, P.O. Box 513, MB Eindhoven, The Netherlands
- Department of Surgery, Catharina Hospital Eindhoven, ZA Eindhoven, The Netherlands
| | - Richard G P Lopata
- Cardiovascular Biomechanics Group, Department of Biomedical Engineering, Eindhoven University of Technology, P.O. Box 513, MB Eindhoven, The Netherlands
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36
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Farotto D, Segers P, Meuris B, Vander Sloten J, Famaey N. The role of biomechanics in aortic aneurysm management: requirements, open problems and future prospects. J Mech Behav Biomed Mater 2018; 77:295-307. [DOI: 10.1016/j.jmbbm.2017.08.019] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Revised: 08/09/2017] [Accepted: 08/15/2017] [Indexed: 12/18/2022]
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37
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Qiu Y, Yuan D, Wen J, Fan Y, Zheng T. Numerical identification of the rupture locations in patient-specific abdominal aortic aneurysmsusing hemodynamic parameters. Comput Methods Biomech Biomed Engin 2017; 21:1-12. [PMID: 29251991 DOI: 10.1080/10255842.2017.1410796] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The rupture of an abdominal aortic aneurysm (AAA) is generally an unexpected event. Up to now, there is no agreement on an accurate criteria to predict the rupture risk of AAAs. This paper aims to numerically investigate the hemodynamics of three ruptured and one non-ruptured patient-specific AAA models to correlate local hemodynamic parameters with the rupture sites, and for the first time, this study introduced helicity as a potential index for the rupture potential of AAAs.3D reconstructions from CT scans were done. The simulation revealed that all the rupture sites were in regions of stagnation with near zero wall shear stress (WSS) but large WSS gradient (WSSG), which may explain the observation by the former researchers that the rupture site in the ruptured AAA has the lowest recorded wall thickness compared to other non-ruptured regions. Moreover, all the ruptures occurred at regions of zero helicity which represents a purely axial or circumferential flow. In addition, this study revealed that the double low region for the non-ruptured AAA was present with a thick layer of plaques, it suggests that the AAA rupture and the formation of atherosclerotic plaques may share a lot common physiological features. However, the fact that there are no plaques present in the walls of three RAAAs also indicates that AAA is not always a result of atherosclerosis. The current computational study may complement the maximum diameter, peak wall stress and other clinically relevant factors in AAA ruptures to identify the rupture sites of AAAs.
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Affiliation(s)
- Yue Qiu
- a Department of Applied Mechanics , Sichuan University , Chengdu , China
| | - Ding Yuan
- b Department Vascular Surgery of West China Hospital , Sichuan University , Chengdu , China
| | - Jun Wen
- c School of Civil Engineering and Architecture , Southwest University of Science and Technology , Mianyang , China
| | - Yubo Fan
- d Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering , Beihang University , Beijing , P.R. China
| | - Tinghui Zheng
- a Department of Applied Mechanics , Sichuan University , Chengdu , China
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Villard C, Hultgren R. Abdominal aortic aneurysm: Sex differences. Maturitas 2017; 109:63-69. [PMID: 29452784 DOI: 10.1016/j.maturitas.2017.12.012] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Revised: 12/11/2017] [Accepted: 12/12/2017] [Indexed: 02/06/2023]
Abstract
OBJECTIVE Abdominal aortic aneurysm (AAA) predominantly affects an elderly male population. Even so, AAA appears more detrimental in women, who experience a higher risk of aneurysm rupture and a worse outcome after surgery than men. Why women are privileged from yet are worse off once affected has been attributed to an effect of sex hormones. This review summarizes the knowledge of sex differences in AAA and addresses the changes in the aneurysm wall from a gender perspective. METHOD Standard reporting guidelines set by the PRISMA Group were followed to identify studies examining AAA from a gender perspective. Relevant reports were identified using two electronic databases: PubMed and Web of Science. The systematic search was performed in two stages: firstly, using the terms AAA and gender/sex/women; and secondly, adding the terms "elastin", "collagen" and "vascular smooth muscle cells", in order to filter the search for studies relevant to our focus on the aneurysm wall. CONCLUSION Current studies support the theory that sex has an effect on aneurysm formation, yet are inconclusive about whether or not aneurysm formation is dependent on female/male sex hormones or a lack thereof. The studies in women are scarce and out of those most reports primarily address other end-points, which limit their ability to illuminate an effect of sex on aneurysm formation. The complexity of the human menstrual cycle and menopausal transition are difficult to mimic in animal models, which limit their applicability to AAA formation in humans.
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Affiliation(s)
- Christina Villard
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden.
| | - Rebecka Hultgren
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden; Department of Vascular Surgery, Karolinska University Hospital, Stockholm, Sweden
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Viceconti M, Cobelli C, Haddad T, Himes A, Kovatchev B, Palmer M. In silico assessment of biomedical products: The conundrum of rare but not so rare events in two case studies. Proc Inst Mech Eng H 2017; 231:455-466. [PMID: 28427321 DOI: 10.1177/0954411917702931] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
In silico clinical trials, defined as "The use of individualized computer simulation in the development or regulatory evaluation of a medicinal product, medical device, or medical intervention," have been proposed as a possible strategy to reduce the regulatory costs of innovation and the time to market for biomedical products. We review some of the the literature on this topic, focusing in particular on those applications where the current practice is recognized as inadequate, as for example, the detection of unexpected severe adverse events too rare to be detected in a clinical trial, but still likely enough to be of concern. We then describe with more details two case studies, two successful applications of in silico clinical trial approaches, one relative to the University of Virginia/Padova simulator that the Food and Drug Administration has accepted as possible replacement for animal testing in the preclinical assessment of artificial pancreas technologies, and the second, an investigation of the probability of cardiac lead fracture, where a Bayesian network was used to combine in vivo and in silico observations, suggesting a whole new strategy of in silico-augmented clinical trials, to be used to increase the numerosity where recruitment is impossible, or to explore patients' phenotypes that are unlikely to appear in the trial cohort, but are still frequent enough to be of concern.
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Affiliation(s)
- Marco Viceconti
- 1 Department of Mechanical Engineering, INSIGNEO Institute for in silico Medicine, The University of Sheffield, Sheffield, UK
| | - Claudio Cobelli
- 2 Department of Information Engineering, University of Padova, Padova, Italy
| | | | | | - Boris Kovatchev
- 4 Center for Diabetes Technology, The University of Virginia, Charlottesville, VA, USA
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40
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Novak K, Polzer S, Bursa J. Applicability of simplified computational models in prediction of peak wall stress in abdominal aortic aneurysms. Technol Health Care 2017; 26:165-173. [PMID: 29172016 DOI: 10.3233/thc-171024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
In the paper impact of different material models on the calculated peak wall stress (PWS) and peak wall rupture risk (PWRR) in abdominal aortic aneurysms (AAAs) is assessed. Computational finite element models of 70 patient-specific AAAs were created using two different material models - a realistic one based on mean population results of uniaxial tests of AAA wall considered as reference, and a 100 times stiffer artificial model. The calculated results of PWS and PWRR were tested to evaluate statistical significance of differences caused by the non-realistic material model. It was shown that for majority of AAAs the differences are insignificant but for some 10% of them their relative differences exceed 20% which may lead to incorrect decisions on their surgical treatment. This percentage of failures favours application of realistic material models in clinical practise although they are much more time-consuming.
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41
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Rowbotham SE, Pinchbeck JL, Anderson G, Bourke B, Bourke M, Gasser TC, Jaeggi R, Jenkins JS, Moran CS, Morton SK, Reid CM, Velu R, Yip L, Moxon JV, Golledge J. Inositol in the MAnaGemENt of abdominal aortic aneurysm (IMAGEN): study protocol for a randomised controlled trial. Trials 2017; 18:547. [PMID: 29145894 PMCID: PMC5692794 DOI: 10.1186/s13063-017-2304-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Accepted: 10/31/2017] [Indexed: 12/20/2022] Open
Abstract
Background An abdominal aortic aneurysm (AAA) is a focal dilation of the abdominal aorta and is associated with a risk of fatal rupture. Experimental studies suggest that myo-inositol may exert beneficial effects on AAAs through favourable changes to biological pathways implicated in AAA pathology. The aim of the Inositol in the MAnaGemENt of abdominal aortic aneurysm (IMAGEN) trial is to assess if myo-inositol will reduce AAA growth. Methods/design IMAGEN is a multi-centre, prospective, parallel-group, randomised, double-blind, placebo-controlled trial. A total of 164 participants with an AAA measuring ≥ 30 mm will be randomised to either 2 g of myo-inositol or identical placebo twice daily for 12 months. The primary outcome measure will be AAA growth estimated by increase in total infrarenal aortic volume measured on computed tomographic scans. Secondary outcome measures will include AAA diameter assessed by computed tomography and ultrasound, AAA peak wall stress and peak wall rupture index, serum lipids, circulating AAA biomarkers, circulating RNAs and health-related quality of life. All analysis will be based on the intention-to-treat principle at the time of randomisation. All patients who meet the eligibility criteria, provide written informed consent and are enrolled in the study will be included in the primary analysis, regardless of adherence to dietary allocation. Discussion Currently, there is no known medical therapy to limit AAA progression. The IMAGEN trial will be the first randomised trial, to our knowledge, to assess the value of myo-inositol in limiting AAA growth. Trial registration Australian New Zealand Clinical Trials Registry, ACTRN12615001209583. Registered on 6 November 2015. Electronic supplementary material The online version of this article (doi:10.1186/s13063-017-2304-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Sophie E Rowbotham
- School of Medicine, The University of Queensland, Herston, QLD, 4006, Australia.,Department of Vascular Surgery, The Royal Brisbane and Women's Hospital, Herston, QLD, 4029, Australia.,Queensland Research Centre for Peripheral Vascular Disease, College of Medicine and Dentistry, James Cook University, Townsville, QLD, 4811, Australia
| | - Jenna L Pinchbeck
- Queensland Research Centre for Peripheral Vascular Disease, College of Medicine and Dentistry, James Cook University, Townsville, QLD, 4811, Australia
| | - Georgina Anderson
- Queensland Research Centre for Peripheral Vascular Disease, College of Medicine and Dentistry, James Cook University, Townsville, QLD, 4811, Australia
| | - Bernie Bourke
- Gosford Vascular Services, Gosford, NSW, 2250, Australia
| | - Michael Bourke
- Queensland Research Centre for Peripheral Vascular Disease, College of Medicine and Dentistry, James Cook University, Townsville, QLD, 4811, Australia.,Gosford Vascular Services, Gosford, NSW, 2250, Australia
| | - T Christian Gasser
- Department of Solid Mechanics, School of Engineering Sciences, KTH Royal Institute of Technology, 100 44, Stockholm, Sweden
| | - Rene Jaeggi
- Queensland Research Centre for Peripheral Vascular Disease, College of Medicine and Dentistry, James Cook University, Townsville, QLD, 4811, Australia
| | - Jason S Jenkins
- Department of Vascular Surgery, The Royal Brisbane and Women's Hospital, Herston, QLD, 4029, Australia
| | - Corey S Moran
- Queensland Research Centre for Peripheral Vascular Disease, College of Medicine and Dentistry, James Cook University, Townsville, QLD, 4811, Australia
| | - Susan K Morton
- Queensland Research Centre for Peripheral Vascular Disease, College of Medicine and Dentistry, James Cook University, Townsville, QLD, 4811, Australia
| | - Christopher M Reid
- School of Public Health, Curtin University, Perth, WA, 6000, Australia.,School of Public Health and Preventive Medicine, Monash University, Melbourne, VIC, 3004, Australia
| | - Ramesh Velu
- Queensland Research Centre for Peripheral Vascular Disease, College of Medicine and Dentistry, James Cook University, Townsville, QLD, 4811, Australia.,Department of Vascular and Endovascular Surgery, The Townsville Hospital, Townsville, QLD, 4811, Australia
| | - Lisan Yip
- Queensland Research Centre for Peripheral Vascular Disease, College of Medicine and Dentistry, James Cook University, Townsville, QLD, 4811, Australia
| | - Joseph V Moxon
- Queensland Research Centre for Peripheral Vascular Disease, College of Medicine and Dentistry, James Cook University, Townsville, QLD, 4811, Australia
| | - Jonathan Golledge
- Queensland Research Centre for Peripheral Vascular Disease, College of Medicine and Dentistry, James Cook University, Townsville, QLD, 4811, Australia. .,Department of Vascular and Endovascular Surgery, The Townsville Hospital, Townsville, QLD, 4811, Australia.
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42
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Stevens RRF, Grytsan A, Biasetti J, Roy J, Lindquist Liljeqvist M, Gasser TC. Biomechanical changes during abdominal aortic aneurysm growth. PLoS One 2017; 12:e0187421. [PMID: 29112945 PMCID: PMC5675455 DOI: 10.1371/journal.pone.0187421] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Accepted: 10/19/2017] [Indexed: 12/11/2022] Open
Abstract
The biomechanics-based Abdominal Aortic Aneurysm (AAA) rupture risk assessment has gained considerable scientific and clinical momentum. However, such studies have mainly focused on information at a single time point, and little is known about how AAA properties change over time. Consequently, the present study explored how geometry, wall stress-related and blood flow-related biomechanical properties change during AAA expansion. Four patients with a total of 23 Computed Tomography-Angiography (CT-A) scans at different time points were analyzed. At each time point, patient-specific properties were extracted from (i) the reconstructed geometry, (ii) the computed wall stress at Mean Arterial Pressure (MAP), and (iii) the computed blood flow velocity at standardized inflow and outflow conditions. Testing correlations between these parameters identified several nonintuitive dependencies. Most interestingly, the Peak Wall Rupture Index (PWRI) and the maximum Wall Shear Stress (WSS) independently predicted AAA volume growth. Similarly, Intra-luminal Thrombus (ILT) volume growth depended on both the maximum WSS and the ILT volume itself. In addition, ILT volume, ILT volume growth, and maximum ILT layer thickness correlated with PWRI as well as AAA volume growth. Consequently, a large ILT volume as well as fast increase of ILT volume over time may be a risk factor for AAA rupture. However, tailored clinical studies would be required to test this hypothesis and to clarify whether monitoring ILT development has any clinical benefit.
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Affiliation(s)
- Raoul R. F. Stevens
- Department of Biomedical Engineering, University of Technology, Eindhoven, The Netherlands
- Department of Biomedical Engineering, Maastricht University, Maastricht, The Netherlands
- KTH Solid Mechanics, School of Engineering Sciences, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Andrii Grytsan
- KTH Solid Mechanics, School of Engineering Sciences, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Jacopo Biasetti
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, United States of America
| | - Joy Roy
- Department of Molecular Medicine and Surgery, Karolinska Institute, Stockholm, Sweden
| | | | - T. Christian Gasser
- KTH Solid Mechanics, School of Engineering Sciences, KTH Royal Institute of Technology, Stockholm, Sweden
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Abstract
Biomedical research and clinical practice are struggling to cope with the growing complexity that the progress of health care involves. The most challenging diseases, those with the largest socioeconomic impact (cardiovascular conditions; musculoskeletal conditions; cancer; metabolic, immunity, and neurodegenerative conditions), are all characterized by a complex genotype-phenotype interaction and by a "systemic" nature that poses a challenge to the traditional reductionist approach. In 2005 a small group of researchers discussed how the vision of computational physiology promoted by the Physiome Project could be translated into clinical practice and formally proposed the term Virtual Physiological Human. Our knowledge about these diseases is fragmentary, as it is associated with molecular and cellular processes on the one hand and with tissue and organ phenotype changes (related to clinical symptoms of disease conditions) on the other. The problem could be solved if we could capture all these fragments of knowledge into predictive models and then compose them into hypermodels that help us tame the complexity that such systemic behavior involves. In 2005 this was simply not possible-the necessary methods and technologies were not available. Now, 10 years later, it seems the right time to reflect on the original vision, the results achieved so far, and what remains to be done.
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Affiliation(s)
- Marco Viceconti
- Department of Mechanical Engineering and Insigneo Institute for in silico Medicine, University of Sheffield, Sheffield S1 3JD, United Kingdom;
| | - Peter Hunter
- Auckland Bioengineering Institute, University of Auckland, Auckland 1142, New Zealand
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Joldes GR, Miller K, Wittek A, Forsythe RO, Newby DE, Doyle BJ. BioPARR: A software system for estimating the rupture potential index for abdominal aortic aneurysms. Sci Rep 2017; 7:4641. [PMID: 28680081 PMCID: PMC5498605 DOI: 10.1038/s41598-017-04699-1] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Accepted: 05/19/2017] [Indexed: 11/25/2022] Open
Abstract
An abdominal aortic aneurysm (AAA) is a permanent and irreversible dilation of the lower region of the aorta. It is a symptomless condition that, if left untreated, can expand until rupture. Despite ongoing efforts, an efficient tool for accurate estimation of AAA rupture risk is still not available. Furthermore, a lack of standardisation across current approaches and specific obstacles within computational workflows limit the translation of existing methods to the clinic. This paper presents BioPARR (Biomechanics based Prediction of Aneurysm Rupture Risk), a software system to facilitate the analysis of AAA using a finite element analysis based approach. Except semi-automatic segmentation of the AAA and intraluminal thrombus (ILT) from medical images, the entire analysis is performed automatically. The system is modular and easily expandable, allows the extraction of information from images of different modalities (e.g. CT and MRI) and the simulation of different modelling scenarios (e.g. with/without thrombus). The software uses contemporary methods that eliminate the need for patient-specific material properties, overcoming perhaps the key limitation to all previous patient-specific analysis methods. The software system is robust, free, and will allow researchers to perform comparative evaluation of AAA using a standardised approach. We report preliminary data from 48 cases.
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Affiliation(s)
- Grand Roman Joldes
- Intelligent Systems for Medicine Laboratory, The University of Western Australia, 35 Stirling Highway, Perth, WA, 6009, Australia.
- School of Mechanical and Chemical Engineering, The University of Western Australia, 35 Stirling Highway, Perth, WA, 6009, Australia.
- School of Engineering and Information Technology, Murdoch University, 90 South St, Murdoch, WA, 6150, Australia.
| | - Karol Miller
- Intelligent Systems for Medicine Laboratory, The University of Western Australia, 35 Stirling Highway, Perth, WA, 6009, Australia
- School of Mechanical and Chemical Engineering, The University of Western Australia, 35 Stirling Highway, Perth, WA, 6009, Australia
- School of Engineering, Cardiff University, The Parade, CF24 3AA, Cardiff, UK
| | - Adam Wittek
- Intelligent Systems for Medicine Laboratory, The University of Western Australia, 35 Stirling Highway, Perth, WA, 6009, Australia
- School of Mechanical and Chemical Engineering, The University of Western Australia, 35 Stirling Highway, Perth, WA, 6009, Australia
| | - Rachael O Forsythe
- BHF Centre for Cardiovascular Science, The University of Edinburgh, Edinburgh, UK
| | - David E Newby
- BHF Centre for Cardiovascular Science, The University of Edinburgh, Edinburgh, UK
| | - Barry J Doyle
- School of Mechanical and Chemical Engineering, The University of Western Australia, 35 Stirling Highway, Perth, WA, 6009, Australia
- BHF Centre for Cardiovascular Science, The University of Edinburgh, Edinburgh, UK
- Vascular Engineering Laboratory, Harry Perkins Institute of Medical Research, QEII Medical Centre, and Centre for Medical Research, The University of Western Australia, Perth, WA, 6009, Australia
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Koncar IB, Nikolic D, Milosevic Z, Ilic N, Dragas M, Sladojevic M, Markovic M, Filipovic N, Davidovic L. Morphological and Biomechanical Features in Abdominal Aortic Aneurysm with Long and Short Neck-Case-Control Study in 64 Abdominal Aortic Aneurysms. Ann Vasc Surg 2017; 45:223-230. [PMID: 28666818 DOI: 10.1016/j.avsg.2017.06.054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Revised: 06/08/2017] [Accepted: 06/08/2017] [Indexed: 10/19/2022]
Abstract
BACKGROUND Both, open and endovascular, procedures are related to higher complication rate in abdominal aortic aneurysm (AAA) with shorter neck. Previous study showed that long-neck AAA might have lower risk of rupture. Estimation of biomechanical forces in AAA improves rupture risk assessment. The aim of this study was to compare morphological features and biomechanical forces in the short- and long-neck AAA with threshold of 15 mm. METHODS Digital Imaging and Communication in Medicine images of 64 aneurysms were prospectively collected and analyzed in a case-control study. Using commercially available software, Peak wall Stress (PWS) and Rupture Risk Equivalent Diameter (RRED) were determined. Difference between the maximal aneurysm diameter (MAD) and RRED was calculated and expressed as an absolute and relative (percentage of the MAD) value. In addition, volume of intraluminal thrombus (ILT) was calculated and expressed relative to AAA volume. RESULTS Study included 64 AAA divided in group with long (36, 56.25%), and short (28, 43.75%) neck. There was no correlation between neck length and MAD, PWS, and RRED (P = 0.646, P = 0.421, and P = 0.405, respectively). Relative ILT volume was greater in the short-neck aneurysms (P = 0.033). Relative difference between RRED and MAD was -4% and -14.8% in short- and long-neck aneurysms, respectively (P = 0.029). The difference between RRED and MAD was positive in 14/28 patients (50%) with short neck and in 6/35 patients (17.14%) with long neck (P = 0.011). CONCLUSIONS Based on our biomechanical analysis, in AAA with neck longer than 15 mm rupture risk might be lower than the risk estimated by its diameter. It might be explained with lower relative volume of ILT.
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Affiliation(s)
- Igor B Koncar
- Faculty of Medicine, University of Belgrade, Belgrade, Serbia; Clinic for Vascular and Endovascular surgery, Clinical Center of Serbia, Belgrade, Serbia.
| | - Dalibor Nikolic
- Research and Development Center for Bioengineering BioIRC, Kragujevac, Serbia; Faculty of Engineering, University of Kragujevac, Kragujevac, Serbia
| | - Zarko Milosevic
- Research and Development Center for Bioengineering BioIRC, Kragujevac, Serbia
| | - Nikola Ilic
- Faculty of Medicine, University of Belgrade, Belgrade, Serbia; Clinic for Vascular and Endovascular surgery, Clinical Center of Serbia, Belgrade, Serbia
| | - Marko Dragas
- Faculty of Medicine, University of Belgrade, Belgrade, Serbia; Clinic for Vascular and Endovascular surgery, Clinical Center of Serbia, Belgrade, Serbia
| | - Milos Sladojevic
- Clinic for Vascular and Endovascular surgery, Clinical Center of Serbia, Belgrade, Serbia
| | - Miroslav Markovic
- Faculty of Medicine, University of Belgrade, Belgrade, Serbia; Clinic for Vascular and Endovascular surgery, Clinical Center of Serbia, Belgrade, Serbia
| | - Nenad Filipovic
- Research and Development Center for Bioengineering BioIRC, Kragujevac, Serbia; Faculty of Engineering, University of Kragujevac, Kragujevac, Serbia
| | - Lazar Davidovic
- Faculty of Medicine, University of Belgrade, Belgrade, Serbia; Clinic for Vascular and Endovascular surgery, Clinical Center of Serbia, Belgrade, Serbia
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de Gelidi S, Tozzi G, Bucchi A. The effect of thickness measurement on numerical arterial models. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2017; 76:1205-1215. [DOI: 10.1016/j.msec.2017.02.123] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Revised: 02/03/2017] [Accepted: 02/24/2017] [Indexed: 10/20/2022]
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Lindquist Liljeqvist M, Hultgren R, Siika A, Gasser TC, Roy J. Gender, smoking, body size, and aneurysm geometry influence the biomechanical rupture risk of abdominal aortic aneurysms as estimated by finite element analysis. J Vasc Surg 2017; 65:1014-1021.e4. [PMID: 28342508 DOI: 10.1016/j.jvs.2016.10.074] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Accepted: 10/14/2016] [Indexed: 11/15/2022]
Abstract
OBJECTIVE Finite element analysis (FEA) has been suggested to be superior to maximal diameter measurements in predicting rupture of abdominal aortic aneurysms (AAAs). Our objective was to investigate to what extent previously described rupture risk factors were associated with FEA-estimated rupture risk. METHODS One hundred forty-six patients with an asymptomatic AAA of a 40- to 60-mm diameter were retrospectively identified and consecutively included. The patients' computed tomography angiograms were analyzed by FEA without (neutral) and with (specific) input of patient-specific mean arterial pressure (MAP), gender, family history, and age. The maximal wall stress/wall strength ratio was described as a rupture risk equivalent diameter (RRED), which translated this ratio into an average aneurysm diameter of corresponding rupture risk. RESULTS In multivariate linear regression, RREDneutral increased with female gender (3.7 mm; 95% confidence interval [CI], 0.13-7.3) and correlated with patient height (0.27 mm/cm; 95% CI, 0.11-0.43) and body surface area (BSA, 16 mm/m2; 95% CI, 8.3-24) and inversely with body mass index (BMI, -0.40 mm/kg m-2; 95% CI, -0.75 to -0.054) in a wall stress-dependent manner. Wall stress-adjusted RREDneutral was raised if the patient was currently smoking (1.1 mm; 95% CI, 0.21-1.9). Age, MAP, family history, and patient weight were unrelated to RREDneutral. In specific FEA, RREDspecific increased with female gender, MAP, family history positive for AAA, height, and BSA, whereas it was inversely related to BMI. All results were independent of aneurysm diameter. Peak wall stress and RRED correlated with aneurysm diameter and lumen volume. CONCLUSIONS Female gender, current smoking, increased patient height and BSA, and low BMI were found to increase the mechanical rupture risk of AAAs. Previously described rupture risk factors may in part be explained by patient characteristic-dependent variations in aneurysm biomechanics.
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Affiliation(s)
| | - Rebecka Hultgren
- Vascular Surgery, Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
| | - Antti Siika
- Vascular Surgery, Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
| | - T Christian Gasser
- Department of Solid Mechanics, School of Engineering Sciences, Royal Institute of Technology, Stockholm, Sweden
| | - Joy Roy
- Vascular Surgery, Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
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48
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Novak K, Polzer S, Krivka T, Vlachovsky R, Staffa R, Kubicek L, Lambert L, Bursa J. Correlation between transversal and orthogonal maximal diameters of abdominal aortic aneurysms and alternative rupture risk predictors. Comput Biol Med 2017; 83:151-156. [PMID: 28282590 DOI: 10.1016/j.compbiomed.2017.03.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Revised: 02/07/2017] [Accepted: 03/03/2017] [Indexed: 11/29/2022]
Abstract
PURPOSE There is no standard for measuring maximal diameter (Dmax) of abdominal aortic aneurysm (AAA) from computer tomography (CT) images although differences between Dmax evaluated from transversal (axialDmax) or orthogonal (orthoDmax) planes can be large especially for angulated AAAs. Therefore we investigated their correlations with alternative rupture risk indicators as peak wall stress (PWS) and peak wall rupture risk (PWRR) to decide which Dmax is more relevant in AAA rupture risk assessment. MATERIAL AND METHODS The Dmax values were measured by a trained radiologist from 70 collected CT scans, and the corresponding PWS and PWRR were evaluated using Finite Element Analysis (FEA). The cohort was ordered according to the difference between axialDmax and orthoDmax (Da-o) quantifying the aneurysm angulation, and Spearman's correlation coefficients between PWS/PWRR - orthoDmax/axialDmax were calculated. RESULTS The calculated correlations PWS/PWRR vs. orthoDmax were substantially higher for angulated AAAs (with Da-o≥3mm). Under this limit, the correlations were almost the same for both Dmax values. Analysis of AAAs divided into two groups of angulated (n=38) and straight (n=32) cases revealed that both groups are similar in all parameters (orthoDmax, PWS, PWRR) with the exception of axialDmax (p=0.024). CONCLUSIONS It was confirmed that orthoDmax is better correlated with the alternative rupture risk predictors PWS and PWRR for angulated AAAs (DA-O≥3mm) while there is no difference between orthoDmax and axialDmax for straight AAAs (DA-O<3mm). As angulated AAAs represent a significant portion of cases it can be recommended to use orthoDmax as the only Dmax parameter for AAA rupture risk assessment.
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Affiliation(s)
- Kamil Novak
- Institute of Solid Mechanics, Mechatronics and Biomechanics, Brno University of Technology, Czech Republic.
| | - Stanislav Polzer
- Institute of Solid Mechanics, Mechatronics and Biomechanics, Brno University of Technology, Czech Republic
| | - Tomas Krivka
- Department of Medical Imaging, St. Anne´s University Hospital and Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Robert Vlachovsky
- 2(nd) Department of Surgery, St. Anne's University Hospital and Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Robert Staffa
- 2(nd) Department of Surgery, St. Anne's University Hospital and Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Lubos Kubicek
- 2(nd) Department of Surgery, St. Anne's University Hospital and Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Lukas Lambert
- Department of Radiology, First Faculty of Medicine, Charles University in Prague and General University Hospital in Prague, Czech Republic
| | - Jiri Bursa
- Institute of Solid Mechanics, Mechatronics and Biomechanics, Brno University of Technology, Czech Republic
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49
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Challenges and opportunities in limiting abdominal aortic aneurysm growth. J Vasc Surg 2017; 65:225-233. [DOI: 10.1016/j.jvs.2016.08.003] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Accepted: 08/08/2016] [Indexed: 11/18/2022]
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Leemans EL, Willems TP, van der Laan MJ, Slump CH, Zeebregts CJ. Biomechanical Indices for Rupture Risk Estimation in Abdominal Aortic Aneurysms. J Endovasc Ther 2016; 24:254-261. [PMID: 27872318 DOI: 10.1177/1526602816680088] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
PURPOSE To review the use of biomechanical indices for the estimation of abdominal aortic aneurysm (AAA) rupture risk, emphasizing their potential use in a clinical setting. METHODS A search of the PubMed, Embase, Scopus, and Compendex databases was made up to June 2015 to identify articles involving biomechanical analysis of AAA rupture risk. Outcome variables [aneurysm diameter, peak wall stress (PWS), peak wall shear stress (PWSS), wall strain, peak wall rupture index (PWRI), and wall stiffness] were compared for asymptomatic intact AAAs vs symptomatic or ruptured AAAs. For quantitative analysis of the pooled data, a random effects model was used to calculate the standard mean differences (SMDs) with the 95% confidence interval (CI) for the biomechanical indices. RESULTS The initial database searches yielded 1894 independent articles of which 19 were included in the analysis. The PWS was significantly higher in the symptomatic/ruptured group, with a SMD of 1.11 (95% CI 0.93 to 1.26, p<0.001). Likewise, the PWRI was significantly higher in the ruptured or symptomatic group, with a SMD of 1.15 (95% CI 0.30 to 2.01, p=0.008). After adjustment for the aneurysm diameter, the PWS remained higher in the ruptured or symptomatic group, with a SMD of 0.85 (95% CI 0.46 to 1.23, p<0.001). Less is known of the wall shear stress and wall strain indices, as too few studies were available for analysis. CONCLUSION Biomechanical indices are a promising tool in the assessment of AAA rupture risk as they incorporate several factors, including geometry, tissue properties, and patient-specific risk factors. However, clinical implementation of biomechanical AAA assessment remains a challenge owing to a lack of standardization.
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Affiliation(s)
- Eva L Leemans
- 1 Department of Surgery, Division of Vascular Surgery, University Medical Center Groningen, University of Groningen, the Netherlands.,2 Department of Biomechanical Engineering and Physics, Academic Medical Centre, Amsterdam, the Netherlands.,3 Department of Radiology, Academic Medical Centre, Amsterdam, the Netherlands.,4 MIRA Institute for Biomedical Engineering and Technical Medicine, University of Twente, Enschede, the Netherlands
| | - Tineke P Willems
- 5 Department of Radiology, University Medical Center Groningen, University of Groningen, the Netherlands
| | - Maarten J van der Laan
- 1 Department of Surgery, Division of Vascular Surgery, University Medical Center Groningen, University of Groningen, the Netherlands
| | - Cornelis H Slump
- 4 MIRA Institute for Biomedical Engineering and Technical Medicine, University of Twente, Enschede, the Netherlands
| | - Clark J Zeebregts
- 1 Department of Surgery, Division of Vascular Surgery, University Medical Center Groningen, University of Groningen, the Netherlands
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