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Malatos S, Fazzini L, Raptis A, Nana P, Kouvelos G, Tasso P, Gallo D, Morbiducci U, Xenos MA, Giannoukas A, Matsagkas M. Evaluation of Hemodynamic Properties After Chimney and Fenestrated Endovascular Aneurysm Repair. Ann Vasc Surg 2024; 104:237-247. [PMID: 38492732 DOI: 10.1016/j.avsg.2023.12.084] [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: 10/02/2023] [Revised: 12/14/2023] [Accepted: 12/16/2023] [Indexed: 03/18/2024]
Abstract
BACKGROUND Fenestrated (FEVAR) and chimney (ChEVAR) endovascular aortic repair have been applied in anatomically suitable complex aortic aneurysms. However, local hemodynamic changes may occur after repair. This study aimed to compare FEVAR's and ChEVAR's hemodynamic properties, focusing on visceral arteries. METHODS Preoperative and postoperative computed tomography angiographies have been used to reconstruct patient-based models. Data of 3 patients, for each modality, were analyzed. Following geometric reconstruction, computational fluid dynamics simulations were used to extract near-wall and intravascular hemodynamic indicators, such as pressure drops, velocity, wall shear stress, time averaged wall shear stress, oscillatory shear index, relative residence time, and local normalized helicity. RESULTS An overall improvement in hemodynamics was detected after repair, with either technique. Preoperatively, a disturbed prothrombotic wall shear stress profile was recorded in several zones of the sac. The local normalized helicity results showed a better organization of the helical structures at postoperative setting, decreasing thrombus formation, with both modalities. Similarly, time averaged wall shear stress increased and oscillatory shear index decreased postoperatively, signaling nondisturbed blood flow. The relative residence time was locally reduced. The flow in visceral arteries tended to be more streamlined in ChEVAR, compared to evident recirculation regions at renal and superior mesenteric artery fenestrations (P = 0.06). CONCLUSIONS ChEVAR and FEVAR seem to improve hemodynamics toward normal values with a reduction of recirculation zones in the main graft and aortic branches. Visceral artery flow comparison revealed that ChEVAR tended to present lower recirculation regions at parallel grafts' entries while FEVAR showed less intense flow regurgitation in visceral stents.
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Affiliation(s)
- Stavros Malatos
- Laboratory for Vascular Simulations, Institute of Vascular Diseases, Larissa, Greece
| | - Laura Fazzini
- Department of Mechanical and Aerospace Engineering, Biomedical Engineering, Politecnico di Torino, Torino, Italy
| | - Anastasios Raptis
- Laboratory for Vascular Simulations, Institute of Vascular Diseases, Larissa, Greece
| | - Petroula Nana
- Department of Vascular Surgery, Faculty of Medicine, School of Health Sciences, University of Thessaly, Larissa, Greece.
| | - George Kouvelos
- Department of Vascular Surgery, Faculty of Medicine, School of Health Sciences, University of Thessaly, Larissa, Greece
| | - Paola Tasso
- Department of Mechanical and Aerospace Engineering, Biomedical Engineering, Politecnico di Torino, Torino, Italy
| | - Diego Gallo
- Department of Mechanical and Aerospace Engineering, Biomedical Engineering, Politecnico di Torino, Torino, Italy
| | - Umberto Morbiducci
- Department of Mechanical and Aerospace Engineering, Biomedical Engineering, Politecnico di Torino, Torino, Italy
| | - Michail A Xenos
- Department of Vascular Surgery, Faculty of Medicine, School of Health Sciences, University of Thessaly, Larissa, Greece; Department of Mathematics, Section of Applied and Computational Mathematics, University of Ioannina, Ioannina, Greece
| | - Athanasios Giannoukas
- Laboratory for Vascular Simulations, Institute of Vascular Diseases, Larissa, Greece; Department of Vascular Surgery, Faculty of Medicine, School of Health Sciences, University of Thessaly, Larissa, Greece
| | - Miltiadis Matsagkas
- Laboratory for Vascular Simulations, Institute of Vascular Diseases, Larissa, Greece; Department of Vascular Surgery, Faculty of Medicine, School of Health Sciences, University of Thessaly, Larissa, Greece
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Zhang X, Peng Y, Li G, Li J, Luo M, Che Y, Zheng L, Anzai H, Ohta M, Shu C. Elongation of the proximal descending thoracic aorta and associated hemodynamics increase the risk of acute type B aortic dissection. Technol Health Care 2024; 32:765-777. [PMID: 37545271 DOI: 10.3233/thc-230194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/08/2023]
Abstract
BACKGROUND Acute type B aortic dissection (ATBAD) is a life-threatening aortic disease. However, little information is available on predicting and understanding of ATBAD. OBJECTIVE The study sought to explore the underlying mechanism of ATBAD by analyzing the morphological and hemodynamic characteristics related to aortic length. METHODS The length and tortuosity of the segment and the whole aorta in the ATBAD group (n= 163) and control group (n= 120) were measured. A fixed anatomic landmark from the distal of left subclavian artery (LSA) to the superior border of sixth thoracic vertebra was proposed as the proximal descending thoracic aorta (PDTA), and the dimensionless parameter, length ratio, was introduced to eliminate the individual differences. The significant morphological parameters were filtrated and the associations between parameters were investigated using statistical approaches. Furthermore, how aortic morphology influenced ATBAD was explored based on idealized aortic models and hemodynamic-related metrics. RESULTS The PDTA length was significantly increased in the ATBAD group compared with the control group and had a strong positive correlation with the whole aortic length (r= 0.89). The length ratio (LR2) and tortuosity (T2) of PDTA in the ATBAD group were significantly increased (0.15 ± 0.02 vs 0.12 ± 0.02 and 1.73 ± 0.48 vs 1.50 ± 0.36; P< 0.001), and LR2 was positive correlation with T2 (r= 0.73). In receiver-operating curve analysis, the area under the curve was 0.835 for LR2 and 0.641 for T2. Low and oscillatory shear (LOS) was positive correlation with LR2, and the elevated LOS occurred in the distal of LSA. CONCLUSION Elongation of PDTA is associated with ATBAD, and the length ratio is a novel predictor. Elongated PDTA induced more aggressive hemodynamic forces, and high LOS regions may correspond to the entry tear location. The synergy of the morphological variation and aggressive hemodynamics creates contributory conditions for ATBAD.
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Affiliation(s)
- Xuelan Zhang
- School of Mathematics and Physics, University of Science and Technology Beijing, Beijing, China
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, China
| | - Yuan Peng
- Department of Vascular Surgery, Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Gaoyang Li
- Institute of Fluid Science, Tohoku University, Sendai, Japan
| | - Jiehua Li
- Department of Vascular Surgery, Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Mingyao Luo
- Department of Vascular Surgery, Fuwai Hospital, Chinese Academy of Medical Science & Peking Union Medical College, Beijing, China
| | - Yue Che
- School of Mathematics and Physics, University of Science and Technology Beijing, Beijing, China
| | - Liancun Zheng
- School of Mathematics and Physics, University of Science and Technology Beijing, Beijing, China
| | - Hitomi Anzai
- Institute of Fluid Science, Tohoku University, Sendai, Japan
| | - Makoto Ohta
- Institute of Fluid Science, Tohoku University, Sendai, Japan
| | - Chang Shu
- Department of Vascular Surgery, Second Xiangya Hospital, Central South University, Changsha, Hunan, China
- Department of Vascular Surgery, Fuwai Hospital, Chinese Academy of Medical Science & Peking Union Medical College, Beijing, China
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Wilson SI, Ingram KE, Oh A, Moreno MR, Kassi M. The role of innovative modeling and imaging techniques in improving outcomes in patients with LVAD. Front Cardiovasc Med 2023; 10:1248300. [PMID: 37692033 PMCID: PMC10484111 DOI: 10.3389/fcvm.2023.1248300] [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: 06/27/2023] [Accepted: 08/10/2023] [Indexed: 09/12/2023] Open
Abstract
Heart failure remains a significant cause of mortality in the United States and around the world. While organ transplantation is acknowledged as the gold standard treatment for end stage heart failure, supply is limited, and many patients are treated with left ventricular assist devices (LVADs). LVADs extend and improve patients' lives, but they are not without their own complications, particularly the hemocompatibility related adverse events (HRAE) including stroke, bleeding and pump thrombosis. Mainstream imaging techniques currently in use to assess appropriate device function and troubleshoot complications, such as echocardiography and cardiac computed tomography, provide some insight but do not provide a holistic understanding of pump induced flow alterations that leads to HRAEs. In contrast, there are technologies restricted to the benchtop-such as computational fluid dynamics and mock circulatory loops paired with methods like particle image velocimetry-that can assess flow metrics but have not been optimized for clinical care. In this review, we outline the potential role and current limitations of converging available technologies to produce novel imaging techniques, and the potential utility in evaluating hemodynamic flow to determine whether LVAD patients may be at higher risk of HRAEs. This addition to diagnostic and monitoring capabilities could improve prevention and treatment of LVAD-induced complications in heart failure patients.
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Affiliation(s)
- Shannon I. Wilson
- Department of Biomedical Engineering, Texas A&M University, College Station, TX, United States
| | - Katelyn E. Ingram
- DeBakey Heart and Vascular- Heart Center Research, Houston Methodist Research Institute, Houston, TX, United States
| | - Albert Oh
- School of Engineering Medicine, Texas A&M University, Houston, TX, United States
| | - Michael R. Moreno
- J. Mike Walker ‘66 Department of Mechanical Engineering, Texas A&M University, College Station, TX, United States
| | - Mahwash Kassi
- Cardiology, DeBakey Heart and Vascular, Houston Methodist Hospital, Houston, TX, United States
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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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Tzirakis K, Kamarianakis Y, Kontopodis N, Ioannou CV. The Effect of Blood Rheology and Inlet Boundary Conditions on Realistic Abdominal Aortic Aneurysms under Pulsatile Flow Conditions. Bioengineering (Basel) 2023; 10:bioengineering10020272. [PMID: 36829766 PMCID: PMC9953019 DOI: 10.3390/bioengineering10020272] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Revised: 02/07/2023] [Accepted: 02/17/2023] [Indexed: 02/22/2023] Open
Abstract
BACKGROUND The effects of non-Newtonian rheology and boundary conditions on various pathophysiologies have been studied quite extensively in the literature. The majority of results present qualitative and/or quantitative conclusions that are not thoroughly assessed from a statistical perspective. METHODS The finite volume method was employed for the numerical simulation of seven patient-specific abdominal aortic aneurysms. For each case, five rheological models and three inlet velocity boundary conditions were considered. Outlier- and heteroscedasticity-robust ANOVA tests assessed the simultaneous effect of rheological specifications and boundary conditions on fourteen variables that capture important characteristics of vascular flows. RESULTS The selection of inlet velocity profiles appears as a more critical factor relative to rheological specifications, especially regarding differences in the oscillatory characteristics of computed flows. Response variables that relate to the average tangential force on the wall over the entire cycle do not differ significantly across alternative factor levels, as long as one focuses on non-Newtonian specifications. CONCLUSIONS The two factors, namely blood rheological models and inlet velocity boundary condition, exert additive effects on variables that characterize vascular flows, with negligible interaction effects. Regarding thrombus-prone conditions, the Plug inlet profile offers an advantageous hemodynamic configuration with respect to the other two profiles.
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Affiliation(s)
- Konstantinos Tzirakis
- Department of Mechanical Engineering, Hellenic Mediterranean University, 71410 Heraklion, Crete, Greece
- Correspondence:
| | - Yiannis Kamarianakis
- Data Science Group, Institute of Applied and Computational Mathematics, Foundation for Research & Technology-Hellas, 70013 Heraklion, Crete, Greece
| | - Nikolaos Kontopodis
- Vascular Surgery Department, Medical School, University of Crete, 71003 Heraklion, Crete, Greece
| | - Christos V. Ioannou
- Vascular Surgery Department, Medical School, University of Crete, 71003 Heraklion, Crete, Greece
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A systematic review summarizing local vascular characteristics of aneurysm wall to predict for progression and rupture risk of abdominal aortic aneurysms. J Vasc Surg 2023; 77:288-298.e2. [PMID: 35843510 DOI: 10.1016/j.jvs.2022.07.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Revised: 05/06/2022] [Accepted: 07/07/2022] [Indexed: 02/03/2023]
Abstract
OBJECTIVE At present, the rupture risk prediction of abdominal aortic aneurysms (AAAs) and, hence, the clinical decision making regarding the need for surgery, is determined by the AAA diameter and growth rate. However, these measures provide limited predictive information. In the present study, we have summarized the measures of local vascular characteristics of the aneurysm wall that, independently of AAA size, could predict for AAA progression and rupture. METHODS We systematically searched PubMed and Web of Science up to September 13, 2021 to identify relevant studies investigating the relationship between local vascular characteristics of the aneurysm wall and AAA growth or rupture in humans. A quality assessment was performed using the ROBINS-I (risk of bias in nonrandomized studies of interventions) tool. All included studies were divided by four types of measures of arterial wall characteristics: metabolism, calcification, intraluminal thrombus, and compliance. RESULTS A total of 20 studies were included. Metabolism of the aneurysm wall, especially when measured by ultra-small superparamagnetic iron oxide uptake, and calcification were significantly related to AAA growth. A higher intraluminal thrombus volume and thickness had correlated positively with the AAA growth in one study but in another study had correlated negatively. AAA compliance demonstrated no correlation with AAA growth and rupture. The aneurysmal wall characteristics showed no association with AAA rupture. However, the metabolism, measured via ultra-small superparamagnetic iron oxide uptake, but none of the other measures, showed a trend toward a relationship with AAA rupture, although the difference was not statistically significant. CONCLUSIONS The current measures of aortic wall characteristics have the potential to predict for AAA growth, especially the measures of metabolism and calcification. Evidence regarding AAA rupture is scarce, and, although more work is needed, aortic wall metabolism could potentially be related to AAA rupture. This highlights the role of aortic wall characteristics in the progression of AAA but also has the potential to improve the prediction of AAA growth and rupture.
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Carbino B, Guy A, Durka M, Zakerzadeh R. The Effects of Geometric Features of Intraluminal Thrombus on the Vessel Wall Oxygen Deprivation. Front Bioeng Biotechnol 2022; 10:814995. [PMID: 35419349 PMCID: PMC8997837 DOI: 10.3389/fbioe.2022.814995] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2021] [Accepted: 02/21/2022] [Indexed: 12/20/2022] Open
Abstract
The objective of this paper is to analyze the association of intraluminal thrombus (ILT) presence and morphology with oxygen transport in abdominal aortic aneurysms (AAA) and local hypoxia. The biomechanical role of the ILT layer in the evolution of the aneurysm is still not fully understood. ILT has been shown to create an inflammatory environment by reducing oxygen flux to the arterial wall and therefore decreasing its strength. It has been also hypothesized that the geometry of the ILT may further affect AAA rupture. However, no previous research has attempted to explore the effect of morphological features of ILT on oxygen distributions within the AAA, in a systematic manner. In this study, we perform a comprehensive analysis to investigate how physiologically meaningful variations in ILT geometric characteristics affect oxygen transport within an AAA. We simulate twenty-seven AAA models with variable ILT dimensions and investigate the extent to which ILT attenuates oxygen concentration in the arterial wall. Geometric variations studied include ILT thickness and ILT length, as well as the bulge diameter of the aneurysm which is related to ILT curvature. Computer simulations of coupled fluid flow-mass transport between arterial wall, ILT, and blood are solved and spatial variations of oxygen concentrations within the ILT and wall are obtained. The comparison of the results for all twenty-seven simulations supports the hypothesis that the presence of ILT in AAA correlates to significantly impaired oxygen transport to the aneurysmal wall. Mainly, we observed that ILT thickness and length are the parameters that influence decreased oxygen flow and concentration values the most, and thick thrombi exacerbate hypoxic conditions in the arterial wall, which may contribute to increased tissue degradation. Conversely, we observed that the arterial wall oxygen concentration is nearly independent of the AAA bulge diameter. This confirms that consideration of ILT size and anatomy is crucial in the analysis of AAA development.
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Affiliation(s)
- Burton Carbino
- Department of Engineering, Rangos School of Health Sciences, Duquesne University, Pittsburgh, PA, United States
| | - Alexander Guy
- Department of Engineering, Rangos School of Health Sciences, Duquesne University, Pittsburgh, PA, United States
| | - Michael Durka
- NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, United States
- Department of Mechanical Engineering and Materials Science, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA, United States
| | - Rana Zakerzadeh
- Department of Engineering, Rangos School of Health Sciences, Duquesne University, Pittsburgh, PA, United States
- *Correspondence: Rana Zakerzadeh,
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Zhou Z, Teng B, Zhao Y, Wang Z. Comparison of small symptomatic and asymptomatic abdominal aortic aneurysms based on computational fluid dynamics analysis. Medicine (Baltimore) 2021; 100:e27306. [PMID: 34596128 PMCID: PMC8483881 DOI: 10.1097/md.0000000000027306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 09/06/2021] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND The purpose of this study was to compare the hemodynamic parameters of symptomatic and asymptomatic abdominal aortic aneurysms (AAAs) to explore the risk factors for AAA rupture. METHODS We conducted a retrospective analysis of 26 patients with symptomatic small AAAs and 60 patients with asymptomatic small AAAs. Computational fluid dynamics methods were used to compare hemodynamic characteristics between the symptomatic and asymptomatic groups and to evaluate risk factors for the occurrence of symptomatic AAAs. RESULTS The maximum diameters in the symptomatic and asymptomatic groups were 49.7 ± 4.94 mm and 48.4 ± 4.55 mm, respectively. Wall shear stress values at turbulent flow regions in the symptomatic and asymptomatic groups were 0.0098 ± 0.0084 Pa versus 0.0174 ± 0.0068 Pa, respectively. Shear stress values at the site with maximal blood flow impact force in the symptomatic and asymptomatic groups were 1.13 ± 0.466 Pa and 2.04 ± 0.42 Pa, respectively. The areas of the intra-luminal thrombus in the section with the maximum diameter in the symptomatic and asymptomatic groups were 952.19 ± 413.53 mm2 versus 646.63 ± 296.88 mm2, respectively. CONCLUSION The wall shear stress in the symptomatic group was lower than that in the asymptomatic group.
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Lisický O, Hrubanová A, Burša J. Interpretation of Experimental Data is Substantial for Constitutive Characterization of Arterial Tissue. J Biomech Eng 2021; 143:104501. [PMID: 33973008 DOI: 10.1115/1.4051120] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Indexed: 11/08/2022]
Abstract
The paper aims at evaluation of mechanical tests of soft tissues and creation of their representative stress-strain responses and respective constitutive models. Interpretation of sets of experimental results depends highly on the approach to the data analysis. Their common representation through mean and standard deviation may be misleading and give nonrealistic results. In the paper, raw data of seven studies consisting of 11 experimental data sets (concerning carotid wall and atheroma tissues) are re-analyzed to show the importance of their rigorous analysis. The sets of individual uniaxial stress-stretch curves are evaluated using three different protocols: stress-based, stretch-based, and constant-based, and the population-representative response is created by their mean or median values. Except for nearly linear responses, there are substantial differences between the resulting curves, being mostly the highest for constant-based evaluation. But also the stretch-based evaluation may change the character of the response significantly. Finally, medians of the stress-based responses are recommended as the most rigorous approach for arterial and other soft tissues with significant strain stiffening.
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Affiliation(s)
- Ondřej Lisický
- Institute of Solid Mechanics, Mechatronics and Biomechanics, Brno University of Technology, Brno 601 90, Czech Republic
| | - Anna Hrubanová
- Institute of Solid Mechanics, Mechatronics and Biomechanics, Brno University of Technology, Brno 601 90, Czech Republic
| | - Jiří Burša
- Institute of Solid Mechanics, Mechatronics and Biomechanics, Brno University of Technology, Brno 601 90, Czech Republic
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Hauzer W, Ferenc S, Rosińczuk J, Gnus J. The Role of Serum Calprotectin as a New Marker in Abdominal Aortic Aneurysms - A Preliminary Report. Curr Pharm Biotechnol 2021; 22:508-513. [PMID: 33208067 DOI: 10.2174/1389201021666201117095215] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2020] [Revised: 10/05/2020] [Accepted: 10/10/2020] [Indexed: 11/22/2022]
Abstract
BACKGROUND Abdominal Aortic Aneurysm (AAA) remains a surgical challenge. There are many recognizable markers associated with the formation of AAA. Previous experiments carried out on animal models have shown a correlation between serum calprotectin and the occurrence of AAA. OBJECTIVE This study aimed to evaluate the level of calprotectin as a potential diagnostic biomarker in patients with diagnosed AAA. METHODS The study group consisted of 75 patients aged 35-75 years assigned to two groups: a control group (n=43) of healthy subjects without AAA and a study group (n=32) of patients with a diagnosed AAA. The first calprotectin test was performed upon patient admission to the hospital, and the second control test was performed after three months. The concentration of calprotectin in plasma was determined using the Immunoenzymatic Method (ELISA) with the commercially available Assaypro Kit (AssayMax™ Human Calprotectin ELISA Kit), as well as the sandwich method with polyclonal antibodies to human calprotectin and peroxidase enzyme. RESULTS & DISCUSSION Serum calprotectin levels in AAA patients were three times higher than in healthy subjects (p<0.05). A statistically significant twofold decrease in calprotectin concentration was observed after AAA surgery compared to the control group (p<0.05). CONCLUSION Calprotectin levels can be an important marker in the detection of AAA. In conclusion, AAA patients showed a threefold increase in serum calprotectin level and a twofold decrease in this marker after AAA surgery.
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Affiliation(s)
- Willy Hauzer
- Department of General and Vascular Surgery, Regional Specialist Hospital in Wroclaw, Wroclaw, Poland
| | - Stanisław Ferenc
- Department of General and Vascular Surgery, Regional Specialist Hospital in Wroclaw, Wroclaw, Poland
| | - Joanna Rosińczuk
- Department of Nervous System Diseases, Faculty of Health Sciences, Wroclaw Medical University, Wroclaw, Poland
| | - Jan Gnus
- Department of Physiotherapy, Faculty of Health Sciences, Wroclaw Medical University, Wroclaw, Poland
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11
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Imaging Predictive Factors of Abdominal Aortic Aneurysm Growth. J Clin Med 2021; 10:jcm10091917. [PMID: 33925046 PMCID: PMC8124923 DOI: 10.3390/jcm10091917] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 04/22/2021] [Accepted: 04/23/2021] [Indexed: 01/14/2023] Open
Abstract
Background: Variable imaging methods may add important information about abdominal aortic aneurysm (AAA) progression. The aim of this study is to assess available literature data regarding the predictive imaging factors of AAA growth. Methods: This systematic review was conducted using the PRISMA guidelines. A review of the literature was conducted, using PubMed, EMBASE and CENTRAL databases. The quality of the studies was assessed using the Newcastle-Ottawa Scale. Primary outcomes were defined as AAA growth rate and factors associated to sac expansion. Results: The analysis included 23 studies. All patients (2244; mean age; 69.8 years, males; 85%) underwent imaging with different modalities; the initial evaluation was followed by one or more studies to assess aortic expansion. AAA initial diameter was reported in 13 studies (range 19.9–50.9 mm). Mean follow-up was 34.5 months. AAA diameter at the end was ranging between 20.3 and 55 mm. The initial diameter and intraluminal thrombus were characterized as prognostic factors associated to aneurysm expansion. A negative association between atherosclerosis and AAA expansion was documented. Conclusions: Aneurysm diameter is the most studied factor to be associated with expansion and the main indication for intervention. Appropriate diagnostic modalities may account for different anatomical characteristics and identify aneurysms with rapid growth and higher rupture risk. Future perspectives, including computed mathematical models that will assess wall stress and elasticity and further flow characteristics, may offer valuable alternatives in AAA growth prediction.
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Wang H, Ou J, Gong W, Wang H, Freebody J. Morphologic Features of Symptomatic and Ruptured Abdominal Aortic Aneurysm in Asian Patients. Ann Vasc Surg 2020; 72:445-453. [PMID: 33157247 DOI: 10.1016/j.avsg.2020.09.059] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 09/13/2020] [Accepted: 09/22/2020] [Indexed: 11/15/2022]
Abstract
BACKGROUND To evaluate morphologic features of symptomatic and ruptured abdominal aortic aneurysms in Asian patients. METHODS Two hundred sixty four continuous candidates with an abdominal aortic aneurysm (AAA) were retrospectively identified from a tertiary hospital database between January 2017 and May 2019. The patients meeting inclusion criteria were divided into symptomatic or ruptured AAA (srAAA) and asymptomatic AAA (asAAA) groups. Their computed tomography angiographies were reconstructed using centerline technique and the geometric features of AAAs between the 2 groups were compared. RESULTS One hundred two patients fulfilled selection criteria (mean age 71 years, 80 men), comprising 35 srAAAs and 67 asAAAs. There was no essential association between gender, smoking or hypertension, and AAA-associated symptoms or rupture. The maximum diameter (5.8 ± 1.4 cm vs. 5.0 ± 0.9 cm; P = 0.001), length (8.8 ± 0.6 cm vs. 7.0 ± 0.3 cm; P = 0.002), and intraluminal thrombus (ILT) thickness (1.7 ± 0.2 cm vs. 1.3 ± 0.1 cm; P = 0.039) of AAAs were independent risk factors for AAA-associated symptoms or rupture (binary logistic regression, P < 0.05), but AAA length and ILT were strongly correlated with the AAA diameter (Pearson correlation coefficient value of 0.591 and 0.444) whereas other factors such as aneurysmal tortuosity, aneurysmal neck anatomy, or common iliac artery geometry were nonsignificant. CONCLUSIONS AAA diameter, length, and intraluminal thrombus thickness were identified as risk factors for AAA-associated symptoms in Asian patients. While the diameter is regarded as the most important predictor for symptoms and rupture, AAA length and ILT thickness should also be taken into consideration when contemplating intervention, particularly for borderline and smaller aneurysms.
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Affiliation(s)
- Huaxin Wang
- Department of Anesthesiology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Jiale Ou
- Department of Radiology, Renmin Hospital of Wuhan University, Wuhan, China.
| | - Wei Gong
- Department of Radiology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Haibo Wang
- Department of Radiology, Renmin Hospital of Wuhan University, Wuhan, China
| | - John Freebody
- Department of Radiology, The Queen Elizabeth Hospital, Adelaide, Australia
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13
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Zhang X, Luo M, Fang K, Li J, Peng Y, Zheng L, Shu C. Analysis of the formation mechanism and occurrence possibility of Post-Stenotic Dilatation of the aorta by CFD approach. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2020; 194:105522. [PMID: 32422474 DOI: 10.1016/j.cmpb.2020.105522] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 04/24/2020] [Accepted: 04/25/2020] [Indexed: 06/11/2023]
Abstract
BACKGROUND AND OBJECTIVE Post-Stenotic Dilatation (PSD), the common complication of coarctation of the aorta (COA), is a progressive disease involving aortic aneurysm and even rupture. However, there has been no definitive method that could investigate the mechanism of PSD formation, progression and rupture. The purpose of the present work is to analyze the mechanism behind PSD formation and to further assess the risk of COA patients with different coarctation degrees deteriorating into PSD. METHOD Three-dimensional non-Newtonian (Carreau-Yasuda) hemodynamic simulations are performed throughout the cardiac cycle, and a novel parameter (λci¯ intensity) is proposed to evaluate the intensity of vortices within the aorta. The PSD geometry is reconstructed from Computed Tomography scans. To analyze the formation mechanism and occurrence possibility of PSD, the computer technology is utilized to restore the expansive and/or narrow regions to obtain its previous state (COA) and control group (Normal), and to modify the minimum diameter to obtain the aortas with different coarctation degrees. The clinical cases of pre- and post-operation are further introduced to verify the analysis. RESULTS Compared with the Normal, the vortical structures with higher swirling strength are generated and accumulated at the downstream of the coarctation segment after COA occurrence, and partially disappear in the wake of PSD formation. The sequence of λci¯ intensity is COA > PSD > Normal and pre-operation > post-operation. With increasing the degree of coarctation, the λci¯ intensity is higher and the jet-flow becomes more drastic. CONCLUSIONS The formation of PSD is caused by the vortical structures with higher swirling strength accumulating at the downstream of the coarctation segment. An increase in coarctation degree elevates the risk of PSD occurrence and even aneurysmal dilatation.
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Affiliation(s)
- Xuelan Zhang
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing 10083, China; School of Mathematics and Physics, University of Science and Technology Beijing, Beijing 100083, China
| | - Mingyao Luo
- Department of Vascular Surgery, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100037, China
| | - Kun Fang
- Department of Vascular Surgery, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100037, China
| | - Jiehua Li
- Department of Vascular Surgery, the Second Xiangya Hospital, Central South University, Changsha, 410000, China
| | - Yuan Peng
- Department of Vascular Surgery, the Second Xiangya Hospital, Central South University, Changsha, 410000, China
| | - Liancun Zheng
- School of Mathematics and Physics, University of Science and Technology Beijing, Beijing 100083, China.
| | - Chang Shu
- Department of Vascular Surgery, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100037, China.
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14
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Eslami P, Tran J, Jin Z, Karady J, Sotoodeh R, Lu MT, Hoffmann U, Marsden A. Effect of Wall Elasticity on Hemodynamics and Wall Shear Stress in Patient-Specific Simulations in the Coronary Arteries. J Biomech Eng 2020; 142:024503. [PMID: 31074768 PMCID: PMC7105147 DOI: 10.1115/1.4043722] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 04/24/2019] [Indexed: 11/08/2022]
Abstract
Wall shear stress (WSS) has been shown to be associated with myocardial infarction (MI) and progression of atherosclerosis. Wall elasticity is an important feature of hemodynamic modeling affecting WSS calculations. The objective of this study was to investigate the role of wall elasticity on WSS, and justify use of either rigid or elastic models in future studies. Digital anatomic models of the aorta and coronaries were created based on coronary computed tomography angiography (CCTA) in four patients. Hemodynamics was computed in rigid and elastic models using a finite element flow solver. WSS in five timepoints in the cardiac cycle and time averaged wall shear stress (TAWSS) were compared between the models at each 3 mm subsegment and 4 arcs in cross sections along the centerlines of coronaries. In the left main (LM), proximal left anterior descending (LAD), left circumflex (LCX), and proximal right coronary artery (RCA) of the elastic model, the mean percent radial increase 5.95 ± 1.25, 4.02 ± 0.97, 4.08 ± 0.94, and 4.84 ± 1.05%, respectively. WSS at each timepoint in the cardiac cycle had slightly different values; however, when averaged over the cardiac cycle, there were negligible differences between the models. In both the subsegments (n = 704) and subarc analysis, TAWSS in the two models were highly correlated (r = 0.99). In investigation on the effect of coronary wall elasticity on WSS in CCTA-based models, the results of this study show no significant differences in TAWSS justifying using rigid wall models for future larger studies.
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Affiliation(s)
- Parastou Eslami
- Cardiac MR PET CT Program, Massachusetts General Hospital,
Harvard Medical School, Boston, MA
02114
| | - Justin Tran
- Department of Mechanical Engineering, Stanford
University, Stanford, CA 94305
| | - Zexi Jin
- Cardiac MR PET CT Program, Massachusetts General Hospital,
Harvard Medical School, Boston, MA
02114
| | - Julia Karady
- Cardiac MR PET CT Program, Massachusetts General Hospital,
Harvard Medical School, Boston, MA
02114
| | - Romina Sotoodeh
- Cardiac MR PET CT Program, Massachusetts General Hospital,
Harvard Medical School, Boston, MA
02114
| | - Michael T. Lu
- Cardiac MR PET CT Program, Massachusetts General Hospital,
Harvard Medical School, Boston, MA
02114
| | - Udo Hoffmann
- Cardiac MR PET CT Program, Massachusetts General Hospital,
Harvard Medical School, Boston, MA
02114
| | - Alison Marsden
- Departments of Bioengineering and Pediatrics, Institute of
Computational and Mathematical Engineering, Stanford University,
Stanford, CA 94305
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15
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Leach JR, Kao E, Zhu C, Saloner D, Hope MD. On the Relative Impact of Intraluminal Thrombus Heterogeneity on Abdominal Aortic Aneurysm Mechanics. J Biomech Eng 2019; 141:111010. [PMID: 31253989 PMCID: PMC6808003 DOI: 10.1115/1.4044143] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Revised: 06/14/2019] [Indexed: 01/31/2023]
Abstract
Intraluminal thrombus (ILT) is present in the majority of abdominal aortic aneurysms (AAA) of a size warranting consideration for surgical or endovascular intervention. The rupture risk of AAAs is thought to be related to the balance of vessel wall strength and the mechanical stress caused by systemic blood pressure. Previous finite element analyses of AAAs have shown that ILT can reduce and homogenize aneurysm wall stress. These works have largely considered ILT to be homogeneous in mechanical character or have idealized a stiffness distribution through the thrombus thickness. In this work, we use magnetic resonance imaging (MRI) to delineate the heterogeneous composition of ILT in 7 AAAs and perform patient-specific finite element analysis under multiple conditions of ILT layer stiffness disparity. We find that explicit incorporation of ILT heterogeneity in the finite element analysis is unlikely to substantially alter major stress analysis predictions regarding aneurysm rupture risk in comparison to models assuming a homogenous thrombus, provided that the maximal ILT stiffness is the same between models. Our results also show that under a homogeneous ILT assumption, the choice of ILT stiffness from values common in the literature can result in significantly larger variations in stress predictions compared to the effects of thrombus heterogeneity.
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Affiliation(s)
- Joseph R Leach
- Department of Radiology andBiomedical Imaging,University of California, San Francisco,513 Parnassus Avenue Suite S-261,Box 0628,San Francisco, CA 94143e-mail:
| | - Evan Kao
- Department of Radiology andBiomedical Imaging,University of California, San Francisco,San Francisco, CA 94143e-mail:
| | - Chengcheng Zhu
- Department of Radiology andBiomedical Imaging,University of California, San Francisco,San Francisco, CA 94143e-mail:
| | - David Saloner
- Department of Radiology andBiomedical Imaging,University of California, San Francisco,San Francisco, CA 94143e-mail:
| | - Michael D Hope
- Department of Radiology andBiomedical Imaging,University of California, San Francisco,San Francisco, CA 94143e-mail:
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Auricchio F, Conti M, Romarowski RM. Usefulness of computational fluid dynamics in penetrating aortic ulcer. Ann Cardiothorac Surg 2019; 8:492-493. [PMID: 31463213 DOI: 10.21037/acs.2019.06.08] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Ferdinando Auricchio
- Department of Civil Engineering and Architecture, University of Pavia, Pavia, Italy
| | - Michele Conti
- Department of Civil Engineering and Architecture, University of Pavia, Pavia, Italy
| | - Rodrigo M Romarowski
- 3D and Computer Simulation Laboratory, IRCCS-Policlinico San Donato, San Donato Milanese, Italy
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17
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LEACH JOSEPHR, ZHU CHENGCHENG, SALONER DAVID, HOPE MICHAELD. COMPARISON OF TWO METHODS FOR ESTIMATING THE UNLOADED STATE FOR ABDOMINAL AORTIC ANEURYSM STRESS CALCULATIONS. J MECH MED BIOL 2019. [DOI: 10.1142/s0219519419500155] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Biomechanical analyses can be used to better understand the rupture risk of abdominal aortic aneurysms (AAAs) on a patient-specific basis using vascular geometries obtained from medical imaging. Methodologies of varying complexity are used to estimate the unloaded state of the imaged vessel to provide a reference configuration for finite element simulations. In this work, we compare the implementation and results of two of these methods, one based on geometric scaling and the other using an iterative determination of unloaded vessel geometry. We find that the two methods result in significantly different stress predictions, and that the iterative method offers superior geometric accuracy. Our findings lend context to the variation in finite element results presented in the AAA stress analysis literature.
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Affiliation(s)
- JOSEPH R. LEACH
- Department of Radiology and Biomedical Imaging, University of California, 505 Parnassus Avenue, M-391 San Francisco, CA 94143-0628, USA
| | - CHENGCHENG ZHU
- Department of Radiology and Biomedical Imaging, University of California, 505 Parnassus Avenue, M-391 San Francisco, CA 94143-0628, USA
| | - DAVID SALONER
- Department of Radiology and Biomedical Imaging, University of California, 505 Parnassus Avenue, M-391 San Francisco, CA 94143-0628, USA
- Department of Radiology, Veterans Affairs Medical Center, 4150 Clement Street, San Francisco, CA 94121, USA
| | - MICHAEL D. HOPE
- Department of Radiology and Biomedical Imaging, University of California, 505 Parnassus Avenue, M-391 San Francisco, CA 94143-0628, USA
- Department of Radiology, Veterans Affairs Medical Center, 4150 Clement Street, San Francisco, CA 94121, USA
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18
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Relationship of genetic factors with development of aortic dissection and aneurysm. TURK GOGUS KALP DAMAR CERRAHISI DERGISI-TURKISH JOURNAL OF THORACIC AND CARDIOVASCULAR SURGERY 2018; 26:557-564. [PMID: 32082797 DOI: 10.5606/tgkdc.dergisi.2018.16424] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Accepted: 07/31/2018] [Indexed: 11/21/2022]
Abstract
Background This study aims to investigate the relationship between the development of aortic dissections and aneurysms with the polymorphisms of angiotensin converting enzyme gene, methylenetetrahydrofolate reductase gene, plasminogen activator inhibitor-1 gene, and nitric oxide synthase gene. Methods Between April 2009 and July 2014, 38 patients with aortic dissections (28 males, 10 females; mean age 55.1±10.7 years; range, 30 to 78 years) and 67 patients with aortic aneurysms (57 males, 10 females; mean age 63.0±11.4 years; range, 31 to 82 years) were included in this cross-sectional study. The control group consisted of 60 healthy volunteers (41 males, 19 females; mean age 56.3±11.2 years; range, 30 to 82 years) without an aortic aneurysm or dissection, as assessed by thoracoabdominal computed tomography. The prespecified four genes were genotyped with competitive allelespecific polymerase chain reaction. Results The aortic dissection group had higher nitric oxide synthase-3 (4b/4b) expression levels, compared to the control group. The aortic aneurysm group had also higher nitric oxide synthase-3 (4b/4a) expression levels, compared to the control group. Compared to the control group, a higher rate of angiotensin converting enzyme I/D gene polymorphism was detected in the aneurysm group, while higher D/D polymorphism rates were found in the dissection group; although not statistically significant. Conclusion Our study results suggest that the nitric oxide synthase-3 intron 4b/4b and nitric oxide synthase-3 intron 4b/4a gene polymorphisms can be used as a predictor of aortic dissection and aneurysm development.
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Duque Santos A, Reyes Valdivia A, Romero Lozano M, Aracil Sanus E, Ocaña Guaita J, Gandarias Zúñiga C. Resultados preliminares en el análisis de elementos finitos de aneurismas de aorta abdominal en rango no quirúrgico. ANGIOLOGIA 2018. [DOI: 10.1016/j.angio.2018.01.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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20
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Owen B, Bojdo N, Jivkov A, Keavney B, Revell A. Structural modelling of the cardiovascular system. Biomech Model Mechanobiol 2018; 17:1217-1242. [PMID: 29911296 PMCID: PMC6154127 DOI: 10.1007/s10237-018-1024-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Accepted: 04/25/2018] [Indexed: 02/02/2023]
Abstract
Computational modelling of the cardiovascular system offers much promise, but represents a truly interdisciplinary challenge, requiring knowledge of physiology, mechanics of materials, fluid dynamics and biochemistry. This paper aims to provide a summary of the recent advances in cardiovascular structural modelling, including the numerical methods, main constitutive models and modelling procedures developed to represent cardiovascular structures and pathologies across a broad range of length and timescales; serving as an accessible point of reference to newcomers to the field. The class of so-called hyperelastic materials provides the theoretical foundation for the modelling of how these materials deform under load, and so an overview of these models is provided; comparing classical to application-specific phenomenological models. The physiology is split into components and pathologies of the cardiovascular system and linked back to constitutive modelling developments, identifying current state of the art in modelling procedures from both clinical and engineering sources. Models which have originally been derived for one application and scale are shown to be used for an increasing range and for similar applications. The trend for such approaches is discussed in the context of increasing availability of high performance computing resources, where in some cases computer hardware can impact the choice of modelling approach used.
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Affiliation(s)
- Benjamin Owen
- School of Mechanical, Aerospace and Civil Engineering, University of Manchester, George Begg Building, Manchester, M1 3BB, UK.
| | - Nicholas Bojdo
- School of Mechanical, Aerospace and Civil Engineering, University of Manchester, George Begg Building, Manchester, M1 3BB, UK
| | - Andrey Jivkov
- School of Mechanical, Aerospace and Civil Engineering, University of Manchester, George Begg Building, Manchester, M1 3BB, UK
| | - Bernard Keavney
- Division of Cardiovascular Sciences, University of Manchester, AV Hill Building, Manchester, M13 9PT, UK
| | - Alistair Revell
- School of Mechanical, Aerospace and Civil Engineering, University of Manchester, George Begg Building, Manchester, M1 3BB, UK
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21
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The Society for Vascular Surgery practice guidelines on the care of patients with an abdominal aortic aneurysm. J Vasc Surg 2018; 67:2-77.e2. [DOI: 10.1016/j.jvs.2017.10.044] [Citation(s) in RCA: 1150] [Impact Index Per Article: 191.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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22
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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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23
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Paraskevas KI, Torella F, Swaelens C, England A, Chan TY, Shaikh U, McWilliams RG, Fisher RK. Temporal Changes in Intraluminal Thrombus Volume Within Abdominal Aortic Aneurysms: Implications for Planning Endovascular Aneurysm Sealing. J Endovasc Ther 2017; 25:47-51. [PMID: 29251206 DOI: 10.1177/1526602817748585] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE To explore whether or not there are temporal changes in the abdominal aortic aneurysm (AAA) and intraluminal thrombus (ILT) volumes between planning and implantation of the endovascular aneurysm sealing (EVAS) device and how these changes influence lumen volume. METHODS A retrospective review was conducted of 51 AAA patients (mean age 76±7.1 years; 36 men) in whom 2 serial preoperative computed tomography angiograms (CTAs) had been performed within 1 to 18 months before fenestrated endovascular repair. The 2 preoperative CTAs were analyzed to identify changes in total sac, ILT, and lumen volumes. RESULTS Over a median 7.0 months (interquartile range 4, 10), 46 (90%) of 51 AAAs increased in volume between the 2 CTAs. ILT volume increased in 44 aneurysms. In contrast, lumen volume increased in 31 and decreased in 20 AAAs. There was a strong correlation between changes in AAA volume and ILT volume (rs=0.859, p<0.001), which remained significant after adjustment for initial volumes (rs=0.815; p<0.001). There was no correlation between the time interval separating the 2 CTAs and changes in AAA volume (rs=0.115; p=0.421), changes in ILT volume (rs=0.084; p=0.599), or changes in lumen volume (rs=0.060; p=0.676). The AAA growth rate (defined as the change in AAA size/days between CTAs) showed a weak correlation with ILT volume (rs=0.272, p=0.054), which disappeared after adjustment for initial AAA size (rs=-0.002, p=0.991). Between the 2 CTAs, 12 aneurysms crossed the new <1.4 Nellix maximum aorta/lumen diameter ratio. CONCLUSION As AAAs grow, the increase in aortic volume is largely occupied by additional ILT formation, with minimal change in lumen volume. These changes may alter the suitability of the aneurysm for the Nellix device and could have implications for EVAS planning and device deployment.
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Affiliation(s)
- Kosmas I Paraskevas
- 1 Liverpool Vascular and Endovascular Service, Royal Liverpool University Hospital, Liverpool, UK
| | - Francesco Torella
- 1 Liverpool Vascular and Endovascular Service, Royal Liverpool University Hospital, Liverpool, UK
| | - Charles Swaelens
- 1 Liverpool Vascular and Endovascular Service, Royal Liverpool University Hospital, Liverpool, UK
| | | | - Tze Y Chan
- 3 Department of Radiology, Royal Liverpool University Hospital, Liverpool, UK
| | - Usman Shaikh
- 3 Department of Radiology, Royal Liverpool University Hospital, Liverpool, UK
| | | | - Robert K Fisher
- 1 Liverpool Vascular and Endovascular Service, Royal Liverpool University Hospital, Liverpool, UK
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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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Raptis A, Xenos M, Georgakarakos E, Kouvelos G, Giannoukas A, Matsagkas M. Hemodynamic Profile of Two Aortic Endografts Accounting for Their Postimplantation Position. J Med Device 2017. [DOI: 10.1115/1.4035687] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Endovascular aneurysm repair (EVAR) is a clinically effective technique for treating anatomically eligible abdominal aortic aneurysms (AAAs), involving the deployment of an endograft (EG) that is designed to prevent blood leakage in the aneurysmal sac. While most EGs have equivalent operating principles, the hemodynamic environment established by different EGs is not necessarily the same. So, to unveil the post-EVAR hemodynamic properties, we need an EG-specific computational approach that currently lacks from the literature. Endurant and Excluder are two EGs with similar pre-installation designs. We assumed that the flow conditions in the particular EGs do not vary significantly. The hypothesis was tested combining image reconstructions, computational fluid dynamics (CFD), and statistics, taking into account the postimplantation position of the EGs. Ten patients with Endurant EGs and ten patients with Excluder EGs were included in this study. The two groups were matched with respect to the preoperative morphological characteristics of the AAAs. The EG models are derived from image reconstructions of postoperative computed tomography scans. Wall shear stress (WSS), displacement force, velocity, and helicity were calculated in regions of interest within the EG structures, i.e., the main body, the upper and lower part of the limbs. Excluder generated higher WSS compared to Endurant, especially on the lower part of the limbs (p = 0.001). Spatial fluctuations of WSS were observed on the upper part of the Excluder limbs. Higher blood velocity was induced by Excluder in all the regions of interest (p = 0.04, p = 0.01, and p = 0.004). Focal points of secondary flow were detected in the main body of Endurant and the limbs of Excluder. The displacement force acting on the lower part of the Excluder limbs was stronger compared to the Endurant one (p = 0.03). The results showed that two similar EGs implanted in similar AAAs can induce significantly different flow properties. The delineation of the hemodynamic features associated with the various commercially available EGs could further promote the personalization of treatment offered to aneurysmal patients and inspire ideas for the improvement of EG designs in the future.
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Affiliation(s)
- Anastasios Raptis
- Cardiovascular Surgery Department, Sector of Surgery, Faculty of Medicine, School of Health Sciences, University of Ioannina, Ioannina 45500, Greece
- Laboratory for Vascular Simulations, Institute of Vascular Diseases, Ioannina 45500, Greece e-mails:
| | - Michalis Xenos
- Department of Mathematics, University of Ioannina, Ioannina 45500, Greece
- Laboratory for Vascular Simulations, Institute of Vascular Diseases, Ioannina 45500, Greece e-mail:
| | - Efstratios Georgakarakos
- Department of Vascular Surgery, “Democritus” Medical School, University Hospital of Alexandroupolis, Alexandroupolis 68100, Greece e-mail:
| | - George Kouvelos
- Department of Vascular Surgery, Faculty of Medicine, University of Thessaly, Larissa 41334, Greece e-mail:
| | - Athanasios Giannoukas
- Department of Vascular Surgery, Faculty of Medicine, University of Thessaly, Larissa 41334, Greece
- Laboratory for Vascular Simulations, Institute of Vascular Diseases, Ioannina 45500, Greece e-mail:
| | - Miltiadis Matsagkas
- Department of Vascular Surgery, Faculty of Medicine, University of Thessaly, Larissa 41334, Greece
- Laboratory for Vascular Simulations, Institute of Vascular Diseases, Ioannina 45500, Greece e-mails:
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26
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Xenos MA. An Euler–Lagrange approach for studying blood flow in an aneurysmal geometry. Proc Math Phys Eng Sci 2017. [DOI: 10.1098/rspa.2016.0774] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
To numerically study blood flow in an aneurysm, the development of an approach that tracks the moving tissue and accounts for its interaction with the fluid is required. This study presents a mathematical approach that expands fluid mechanics principles, taking into consideration the domain’s motion. The initial fluid equations, derived in Euler form, are expanded to a mixed Euler–Lagrange formulation to study blood flow in the aneurysm during the cardiac cycle. Transport equations are transformed into a moving body-fitted reference frame using generalized curvilinear coordinates. The equations of motion consist of a coupled and nonlinear system of partial differential equations (PDEs). The PDEs are discretized using the finite volume method. Owing to strong coupling and nonlinear terms, a simultaneous solution approach is applied. The results show that velocity is substantially influenced by the pulsating wall. Intensification of polymorphic flow patterns is observed. Increments of Reynolds and Womersley numbers are evident as pulsatility increases. The pressure field reveals areas of a lateral pressure gradient at the aneurysm. As pulsatility increases, the diastolic flow vortex shifts towards the aortic wall, distal to the aneurysmal neck. Wall shear stress is amplified at the shoulders of the moving wall compared with that of the rigid one.
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27
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Bluestein D. Utilizing Computational Fluid Dynamics in Cardiovascular Engineering and Medicine-What You Need to Know. Its Translation to the Clinic/Bedside. Artif Organs 2017; 41:117-121. [PMID: 28181302 DOI: 10.1111/aor.12914] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Danny Bluestein
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, 11794-8181, USA
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28
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Lozowy RJ, Kuhn DCS, Ducas AA, Boyd AJ. The Relationship Between Pulsatile Flow Impingement and Intraluminal Thrombus Deposition in Abdominal Aortic Aneurysms. Cardiovasc Eng Technol 2016; 8:57-69. [DOI: 10.1007/s13239-016-0287-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Accepted: 11/07/2016] [Indexed: 11/28/2022]
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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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30
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Polzer S, Gasser TC. Biomechanical rupture risk assessment of abdominal aortic aneurysms based on a novel probabilistic rupture risk index. J R Soc Interface 2016; 12:20150852. [PMID: 26631334 DOI: 10.1098/rsif.2015.0852] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
A rupture risk assessment is critical to the clinical treatment of abdominal aortic aneurysm (AAA) patients. The biomechanical AAA rupture risk assessment quantitatively integrates many known AAA rupture risk factors but the variability of risk predictions due to model input uncertainties remains a challenging limitation. This study derives a probabilistic rupture risk index (PRRI). Specifically, the uncertainties in AAA wall thickness and wall strength were considered, and wall stress was predicted with a state-of-the-art deterministic biomechanical model. The discriminative power of PRRI was tested in a diameter-matched cohort of ruptured (n = 7) and intact (n = 7) AAAs and compared to alternative risk assessment methods. Computed PRRI at 1.5 mean arterial pressure was significantly (p = 0.041) higher in ruptured AAAs (20.21(s.d. 14.15%)) than in intact AAAs (3.71(s.d. 5.77)%). PRRI showed a high sensitivity and specificity (discriminative power of 0.837) to discriminate between ruptured and intact AAA cases. The underlying statistical representation of stochastic data of wall thickness, wall strength and peak wall stress had only negligible effects on PRRI computations. Uncertainties in AAA wall stress predictions, the wide range of reported wall strength and the stochastic nature of failure motivate a probabilistic rupture risk assessment. Advanced AAA biomechanical modelling paired with a probabilistic rupture index definition as known from engineering risk assessment seems to be superior to a purely deterministic approach.
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Affiliation(s)
- Stanislav Polzer
- Institute of Solid Mechanics, Mechatronics and Biomechanics, Brno University of Technology, Brno, Czech Republic
| | - T Christian Gasser
- KTH Solid Mechanics, School of Engineering Sciences, KTH Royal Institute of Technology, Stockholm, Sweden
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Raptis A, Xenos M, Georgakarakos E, Kouvelos G, Giannoukas A, Labropoulos N, Matsagkas M. Comparison of physiological and post-endovascular aneurysm repair infrarenal blood flow. Comput Methods Biomech Biomed Engin 2016; 20:242-249. [DOI: 10.1080/10255842.2016.1215437] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Indrakusuma R, Jalalzadeh H, Planken RN, Marquering HA, Legemate DA, Koelemay MJW, Balm R. Biomechanical Imaging Markers as Predictors of Abdominal Aortic Aneurysm Growth or Rupture: A Systematic Review. Eur J Vasc Endovasc Surg 2016; 52:475-486. [PMID: 27558090 DOI: 10.1016/j.ejvs.2016.07.003] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Accepted: 07/01/2016] [Indexed: 11/20/2022]
Abstract
OBJECTIVES Biomechanical characteristics, such as wall stress, are important in the pathogenesis of abdominal aortic aneurysms (AAA) and can be visualised and quantified using imaging techniques. This systematic review aims to present an overview of all biomechanical imaging markers that have been studied in relation to AAA growth and rupture. METHODS This systematic review followed the PRISMA guidelines. A search in Medline, Embase, and the Cochrane Library identified 1503 potentially relevant articles. Studies were included if they assessed biomechanical imaging markers and their potential association with growth or rupture. RESULTS Twenty-seven articles comprising 1730 patients met the inclusion criteria. Eighteen studies performed wall stress analysis using finite element analysis (FEA), 13 of which used peak wall stress (PWS) to quantify wall stress. Ten of 13 case control FEA studies reported a significantly higher PWS for symptomatic or ruptured AAAs than for intact AAAs. However, in some studies there was confounding bias because of baseline differences in aneurysm diameter between groups. Clinical heterogeneity in methodology obstructed a meaningful meta-analysis of PWS. Three of five FEA studies reported a significant positive association between several wall stress markers, such as PWS and 99th percentile stress, and growth. One study reported a significant negative association and one other study reported no significant association. Studies assessing wall compliance, the augmentation index and wall stress analysis using Laplace's law, computational fluid dynamics and fluid structure interaction were also included in this systematic review. CONCLUSIONS Although PWS is significantly higher in symptomatic or ruptured AAAs in most FEA studies, confounding bias, clinical heterogeneity, and lack of standardisation limit the interpretation and generalisability of the results. Also, there is conflicting evidence on whether increased wall stress is associated with growth.
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Affiliation(s)
- R Indrakusuma
- Department of Surgery, Academic Medical Center, Amsterdam, The Netherlands
| | - H Jalalzadeh
- Department of Surgery, Academic Medical Center, Amsterdam, The Netherlands
| | - R N Planken
- Department of Radiology, Academic Medical Center, Amsterdam, The Netherlands
| | - H A Marquering
- Department of Radiology, Academic Medical Center, Amsterdam, The Netherlands; Department of Biomedical Engineering and Physics, Academic Medical Center, Amsterdam, The Netherlands
| | - D A Legemate
- Department of Surgery, Academic Medical Center, Amsterdam, The Netherlands
| | - M J W Koelemay
- Department of Surgery, Academic Medical Center, Amsterdam, The Netherlands
| | - R Balm
- Department of Surgery, Academic Medical Center, Amsterdam, The Netherlands.
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A Review of Computational Methods to Predict the Risk of Rupture of Abdominal Aortic Aneurysms. BIOMED RESEARCH INTERNATIONAL 2015; 2015:861627. [PMID: 26509168 PMCID: PMC4609803 DOI: 10.1155/2015/861627] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Accepted: 05/26/2015] [Indexed: 12/02/2022]
Abstract
Computational methods have played an important role in health care in recent years, as determining parameters that affect a certain medical condition is not possible in experimental conditions in many cases. Computational fluid dynamics (CFD) methods have been used to accurately determine the nature of blood flow in the cardiovascular and nervous systems and air flow in the respiratory system, thereby giving the surgeon a diagnostic tool to plan treatment accordingly. Machine learning or data mining (MLD) methods are currently used to develop models that learn from retrospective data to make a prediction regarding factors affecting the progression of a disease. These models have also been successful in incorporating factors such as patient history and occupation. MLD models can be used as a predictive tool to determine rupture potential in patients with abdominal aortic aneurysms (AAA) along with CFD-based prediction of parameters like wall shear stress and pressure distributions. A combination of these computer methods can be pivotal in bridging the gap between translational and outcomes research in medicine. This paper reviews the use of computational methods in the diagnosis and treatment of AAA.
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Raut SS, Liu P, Finol EA. An approach for patient-specific multi-domain vascular mesh generation featuring spatially varying wall thickness modeling. J Biomech 2015; 48:1972-81. [PMID: 25976018 DOI: 10.1016/j.jbiomech.2015.04.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Revised: 04/02/2015] [Accepted: 04/02/2015] [Indexed: 11/24/2022]
Abstract
In this work, we present a computationally efficient image-derived volume mesh generation approach for vasculatures that implements spatially varying patient-specific wall thickness with a novel inward extrusion of the wall surface mesh. Multi-domain vascular meshes with arbitrary numbers, locations, and patterns of both iliac bifurcations and thrombi can be obtained without the need to specify features or landmark points as input. In addition, the mesh output is coordinate-frame independent and independent of the image grid resolution with high dimensional accuracy and mesh quality, devoid of errors typically found in off-the-shelf image-based model generation workflows. The absence of deformable template models or Cartesian grid-based methods enables the present approach to be sufficiently robust to handle aneurysmatic geometries with highly irregular shapes, arterial branches nearly parallel to the image plane, and variable wall thickness. The assessment of the methodology was based on i) estimation of the surface reconstruction accuracy, ii) validation of the output mesh using an aneurysm phantom, and iii) benchmarking the volume mesh quality against other frameworks. For the phantom image dataset (pixel size 0.105 mm; slice spacing 0.7 mm; and mean wall thickness 1.401±0.120 mm), the average wall thickness in the mesh was 1.459±0.123 mm. The absolute error in average wall thickness was 0.060±0.036 mm, or about 8.6% of the largest image grid spacing (0.7 mm) and 4.36% of the actual mean wall thickness. Mesh quality metrics and the ability to reproduce regional variations of wall thickness were found superior to similar alternative frameworks.
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Affiliation(s)
- Samarth S Raut
- Carnegie Mellon University, Pittsburgh, PA 15213, United States.
| | - Peng Liu
- Carnegie Mellon University, Pittsburgh, PA 15213, United States.
| | - Ender A Finol
- University of Texas at San Antonio, Department of Biomedical Engineering, AET 1.360, One UTSA Circle, San Antonio, TX 78249, United States.
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