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Sarrami-Foroushani A, Nasr Esfahany M, Saligheh Rad H, Firouznia K, Shakiba M, Ghanaati H. Effects of Variations of Flow and Heart Rate on Intra-Aneurysmal Hemodynamics in a Ruptured Internal Carotid Artery Aneurysm During Exercise. IRANIAN JOURNAL OF RADIOLOGY 2016; 13:e18217. [PMID: 27110332 PMCID: PMC4837368 DOI: 10.5812/iranjradiol.18217] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Revised: 06/18/2014] [Accepted: 07/20/2014] [Indexed: 11/16/2022]
Abstract
BACKGROUND Hemodynamics is thought to play an important role in the mechanisms responsible for initiation, growth, and rupture of intracranial aneurysms. Computational fluid dynamic (CFD) analysis is used to assess intra-aneurysmal hemodynamics. OBJECTIVES This study aimed to investigate the effects of variations in heart rate and internal carotid artery (ICA) flow rate on intra-aneurysmal hemodynamics, in an ICA aneurysm, by using computational fluid dynamics. PATIENTS AND METHODS Computed tomography angiography (CTA) was performed in a 55 years old female case, with a saccular ICA aneurysm, to create a patient-specific geometrical anatomic model of the aneurysm. The intra-aneurysmal hemodynamic environments for three states with different flow and heart rates were analyzed using patient-specific image-based CFD modeling. RESULTS Results showed significant changes for the three simulated states. For a proportion of the states examined, results were counterintuitive. Systolic and time-averaged wall shear stress and pressure on the aneurysm wall showed a proportional evolution with the mainstream flow rate. CONCLUSION Results reinforced the pivotal role of vascular geometry, with respect to hemodynamics, together with the importance of performing patient-specific CFD analyses, through which the effect of different blood flow conditions on the aneurysm hemodynamics could be evaluated.
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Affiliation(s)
| | - Mohsen Nasr Esfahany
- Department of Chemical Engineering, Isfahan University of Technology, Isfahan, Iran
- Corresponding author: Mohsen Nasr Esfahany, Department of Chemical Engineering, Isfahan University of Technology, Isfahan, Iran. Tel: +98-3133915631, Fax: +98-3113912677, E-mail:
| | - Hamidreza Saligheh Rad
- Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, Tehran, Iran
| | - Kavous Firouznia
- Advanced Diagnostic and Interventional Radiology Research Center (ADIR), Tehran University of Medical Sciences, Tehran, Iran
| | - Madjid Shakiba
- Advanced Diagnostic and Interventional Radiology Research Center (ADIR), Tehran University of Medical Sciences, Tehran, Iran
| | - Hossein Ghanaati
- Advanced Diagnostic and Interventional Radiology Research Center (ADIR), Tehran University of Medical Sciences, Tehran, Iran
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Wang WH, Wang YH, Zheng LL, Li XW, Hao F, Guo D. MicroRNA-29a: A potential biomarker in the development of intracranial aneurysm. J Neurol Sci 2016; 364:84-9. [PMID: 27084222 DOI: 10.1016/j.jns.2016.03.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Revised: 02/23/2016] [Accepted: 03/03/2016] [Indexed: 12/01/2022]
Abstract
AIM To identify serum microRNA-29a (miR-29a) level in patients with intracranial aneurysm and its role in the development of intracranial aneurysm (IA). METHODS Case group included 165 IA patients hospitalized in the department of neurosurgery between January 2010 and January 2012 while control group enrolled 220 healthy volunteers. Morning fasting blood samples were collected from peripheral vein. RT-PCR was used for miR-29a detection. Receiver Operating Characteristic (ROC) curve was drawn. Survival curves were drawn for survival analysis with Kaplan-Meier method and Long-rank test was conducted. MiR-29a expression Glasgow Prognosis Score (GOS) was used for prognosis scaling. Multivariate Cox proportional hazards regression analysis was performed for prognosis analysis. Results Cases had significantly higher miR-29a expressions than controls (P<0.05). ROC curve analysis indicated that miR-29a expression in IA had high effectiveness in IA diagnosis. Close associations were identified between miR-29a expression and rupture, Hunt-Hess level and surgical timing (all P<0.05). GOS strongly associated with history of hypertension, aneurysm location, rupture, Hunt-Hess level and miR-29a expression. Patients with low miR-29a expression had longer disease-free survival (DFS) and overall survival (OS) than those with high miR-29a expression (both P<0.05). MiR-29a expression, tumor aneurysm, rupture and Hunt-Hess were risk factors to the prognosis of IA (all P<0.05). CONCLUSION MiR-29a may be closely related to IA development and therefore could be a useful predicator of IA prognosis, providing a new target for IA therapy.
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Affiliation(s)
- Wei-Hua Wang
- Central Laboratory, Liaocheng People's Hospital, Liaocheng Clinical School of Taishan Medical University, Liaocheng 252000, PR China
| | - Yun-Hua Wang
- Department of Neurosurgery, Liaocheng People's Hospital, Liaocheng Clinical School of Taishan Medical University, Liaocheng 252000, PR China
| | - Li-Li Zheng
- Central Laboratory, Liaocheng People's Hospital, Liaocheng Clinical School of Taishan Medical University, Liaocheng 252000, PR China
| | - Xiao-Wan Li
- Department of Neurology, Liaocheng People's Hospital, Liaocheng Clinical School of Taishan Medical University, Liaocheng 252000, PR China
| | - Fang Hao
- Department of Neurology, Liaocheng People's Hospital, Liaocheng Clinical School of Taishan Medical University, Liaocheng 252000, PR China.
| | - Dong Guo
- Department of Neurology, Liaocheng People's Hospital, Liaocheng Clinical School of Taishan Medical University, Liaocheng 252000, PR China.
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103
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Huang X, Yin X, Xu Y, Jia X, Li J, Niu P, Shen W, Kassab GS, Tan W, Huo Y. Morphometric and hemodynamic analysis of atherosclerotic progression in human carotid artery bifurcations. Am J Physiol Heart Circ Physiol 2016; 310:H639-47. [PMID: 26747497 DOI: 10.1152/ajpheart.00464.2015] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Accepted: 01/04/2016] [Indexed: 11/22/2022]
Abstract
Although atherosclerosis has been widely investigated at carotid artery bifurcation, there is a lack of morphometric and hemodynamic data at different stages of the disease. The purpose of this study was to determine the lesion difference in patients with carotid artery disease compared with healthy control subjects. The three-dimensional (3D) geometry of carotid artery bifurcation was reconstructed from computed tomography angiography (CTA) images of Chinese control subjects ( n = 30) and patients with carotid artery disease ( n = 30). We defined two novel vector angles (i.e., angles 1 and 2) that were tangential to the reconstructed contour of the 3D vessel. The best-fit diameter was computed along the internal carotid artery (ICA) center line. Hemodynamic analysis was performed at various bifurcations. Patients with stenotic vessels have larger angles 1 and 2 (151 ± 11° and 42 ± 20°) and smaller diameters of the external carotid artery (ECA) (4.6 ± 0.85 mm) compared with control subjects (144 ± 13° and 36 ± 16°, 5.2 ± 0.57 mm) although there is no significant difference in the common carotid artery (CCA) (7.1 ± 1.2 vs. 7.5 ± 1.0 mm, P = 0.18). In particular, all patients with carotid artery disease have a stenosis at the proximal ICA (including both sinus and carina regions), while 20% of patients have stenosis at the middle ICA and 20% have stenosis expansion to the entire cervical ICA. Morphometric and hemodynamic analyses suggest that atherosclerotic plaques initiate at both sinus and carina regions of ICA and progress downstream.
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Affiliation(s)
- Xu Huang
- Department of Mechanics and Engineering Science, College of Engineering, Peking University, Beijing, China
- State Key Laboratory for Turbulence and Complex Systems, College of Engineering, Peking University, Beijing, China
| | - Xiaoping Yin
- Department of Radiology, Affiliated Hospital of Hebei University, Hebei University, Baoding, China
| | - Yingjin Xu
- Department of Radiology, Affiliated Hospital of Hebei University, Hebei University, Baoding, China
| | - Xinwei Jia
- Department of Internal Medicine, Affiliated Hospital of Hebei University, Hebei University, Baoding, China
| | - Jianhui Li
- Department of Ultrasonic Function, Affiliated Hospital of Hebei University, Hebei University, Baoding, China
| | - Pei Niu
- College of Medicine, Hebei University, Baoding, China
| | - Wenzeng Shen
- College of Medicine, Hebei University, Baoding, China
| | - Ghassan S. Kassab
- California Medical Innovations Institute, San Diego, California; and
| | - Wenchang Tan
- Department of Mechanics and Engineering Science, College of Engineering, Peking University, Beijing, China
- State Key Laboratory for Turbulence and Complex Systems, College of Engineering, Peking University, Beijing, China
- Shenzhen Graduate School, Peking University, Shenzhen, China
| | - Yunlong Huo
- Department of Mechanics and Engineering Science, College of Engineering, Peking University, Beijing, China
- State Key Laboratory for Turbulence and Complex Systems, College of Engineering, Peking University, Beijing, China
- College of Medicine, Hebei University, Baoding, China
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104
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Blankena R, Kleinloog R, Verweij BH, van Ooij P, Ten Haken B, Luijten PR, Rinkel GJE, Zwanenburg JJM. Thinner Regions of Intracranial Aneurysm Wall Correlate with Regions of Higher Wall Shear Stress: A 7T MRI Study. AJNR Am J Neuroradiol 2016; 37:1310-7. [PMID: 26892986 DOI: 10.3174/ajnr.a4734] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Accepted: 12/22/2015] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Both hemodynamics and aneurysm wall thickness are important parameters in aneurysm pathophysiology. Our aim was to develop a method for semi-quantitative wall thickness assessment on in vivo 7T MR images of intracranial aneurysms for studying the relation between apparent aneurysm wall thickness and wall shear stress. MATERIALS AND METHODS Wall thickness was analyzed in 11 unruptured aneurysms in 9 patients who underwent 7T MR imaging with a TSE-based vessel wall sequence (0.8-mm isotropic resolution). A custom analysis program determined the in vivo aneurysm wall intensities, which were normalized to the signal of nearby brain tissue and were used as measures of apparent wall thickness. Spatial wall thickness variation was determined as the interquartile range in apparent wall thickness (the middle 50% of the apparent wall thickness range). Wall shear stress was determined by using phase-contrast MR imaging (0.5-mm isotropic resolution). We performed visual and statistical comparisons (Pearson correlation) to study the relation between wall thickness and wall shear stress. RESULTS 3D colored apparent wall thickness maps of the aneurysms showed spatial apparent wall thickness variation, which ranged from 0.07 to 0.53, with a mean variation of 0.22 (a variation of 1.0 roughly means a wall thickness variation of 1 voxel [0.8 mm]). In all aneurysms, apparent wall thickness was inversely related to wall shear stress (mean correlation coefficient, -0.35; P < .05). CONCLUSIONS A method was developed to measure the wall thickness semi-quantitatively, by using 7T MR imaging. An inverse correlation between wall shear stress and apparent wall thickness was determined. In future studies, this noninvasive method can be used to assess spatial wall thickness variation in relation to pathophysiologic processes such as aneurysm growth and rupture.
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Affiliation(s)
- R Blankena
- From the Department of Neurology and Neurosurgery (R.B., R.K., B.H.V., G.J.E.R.) Faculty of Science and Technology (R.B., B.t.H.), Department of Technical Medicine, University of Twente, Enschede, the Netherlands
| | - R Kleinloog
- From the Department of Neurology and Neurosurgery (R.B., R.K., B.H.V., G.J.E.R.)
| | - B H Verweij
- From the Department of Neurology and Neurosurgery (R.B., R.K., B.H.V., G.J.E.R.)
| | - P van Ooij
- Department of Biomedical Engineering and Physics (P.v.O.), Academic Medical Center, Amsterdam, the Netherlands
| | - B Ten Haken
- Faculty of Science and Technology (R.B., B.t.H.), Department of Technical Medicine, University of Twente, Enschede, the Netherlands
| | - P R Luijten
- Brain Center Rudolf Magnus, Department of Radiology (P.R.L., J.J.M.Z.) Image Sciences Institute (P.R.L., J.J.M.Z.), University Medical Center Utrecht, Utrecht, the Netherlands
| | - G J E Rinkel
- From the Department of Neurology and Neurosurgery (R.B., R.K., B.H.V., G.J.E.R.)
| | - J J M Zwanenburg
- Brain Center Rudolf Magnus, Department of Radiology (P.R.L., J.J.M.Z.) Image Sciences Institute (P.R.L., J.J.M.Z.), University Medical Center Utrecht, Utrecht, the Netherlands
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105
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Berg P, Roloff C, Beuing O, Voss S, Sugiyama SI, Aristokleous N, Anayiotos AS, Ashton N, Revell A, Bressloff NW, Brown AG, Jae Chung B, Cebral JR, Copelli G, Fu W, Qiao A, Geers AJ, Hodis S, Dragomir-Daescu D, Nordahl E, Bora Suzen Y, Owais Khan M, Valen-Sendstad K, Kono K, Menon PG, Albal PG, Mierka O, Münster R, Morales HG, Bonnefous O, Osman J, Goubergrits L, Pallares J, Cito S, Passalacqua A, Piskin S, Pekkan K, Ramalho S, Marques N, Sanchi S, Schumacher KR, Sturgeon J, Švihlová H, Hron J, Usera G, Mendina M, Xiang J, Meng H, Steinman DA, Janiga G. The Computational Fluid Dynamics Rupture Challenge 2013—Phase II: Variability of Hemodynamic Simulations in Two Intracranial Aneurysms. J Biomech Eng 2015; 137:121008. [DOI: 10.1115/1.4031794] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Indexed: 11/08/2022]
Abstract
With the increased availability of computational resources, the past decade has seen a rise in the use of computational fluid dynamics (CFD) for medical applications. There has been an increase in the application of CFD to attempt to predict the rupture of intracranial aneurysms, however, while many hemodynamic parameters can be obtained from these computations, to date, no consistent methodology for the prediction of the rupture has been identified. One particular challenge to CFD is that many factors contribute to its accuracy; the mesh resolution and spatial/temporal discretization can alone contribute to a variation in accuracy. This failure to identify the importance of these factors and identify a methodology for the prediction of ruptures has limited the acceptance of CFD among physicians for rupture prediction. The International CFD Rupture Challenge 2013 seeks to comment on the sensitivity of these various CFD assumptions to predict the rupture by undertaking a comparison of the rupture and blood-flow predictions from a wide range of independent participants utilizing a range of CFD approaches. Twenty-six groups from 15 countries took part in the challenge. Participants were provided with surface models of two intracranial aneurysms and asked to carry out the corresponding hemodynamics simulations, free to choose their own mesh, solver, and temporal discretization. They were requested to submit velocity and pressure predictions along the centerline and on specified planes. The first phase of the challenge, described in a separate paper, was aimed at predicting which of the two aneurysms had previously ruptured and where the rupture site was located. The second phase, described in this paper, aims to assess the variability of the solutions and the sensitivity to the modeling assumptions. Participants were free to choose boundary conditions in the first phase, whereas they were prescribed in the second phase but all other CFD modeling parameters were not prescribed. In order to compare the computational results of one representative group with experimental results, steady-flow measurements using particle image velocimetry (PIV) were carried out in a silicone model of one of the provided aneurysms. Approximately 80% of the participating groups generated similar results. Both velocity and pressure computations were in good agreement with each other for cycle-averaged and peak-systolic predictions. Most apparent “outliers” (results that stand out of the collective) were observed to have underestimated velocity levels compared to the majority of solutions, but nevertheless identified comparable flow structures. In only two cases, the results deviate by over 35% from the mean solution of all the participants. Results of steady CFD simulations of the representative group and PIV experiments were in good agreement. The study demonstrated that while a range of numerical schemes, mesh resolution, and solvers was used, similar flow predictions were observed in the majority of cases. To further validate the computational results, it is suggested that time-dependent measurements should be conducted in the future. However, it is recognized that this study does not include the biological aspects of the aneurysm, which needs to be considered to be able to more precisely identify the specific rupture risk of an intracranial aneurysm.
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Affiliation(s)
- Philipp Berg
- University of Magdeburg, Magdeburg 39106, Germany
| | | | - Oliver Beuing
- University Hospital of Magdeburg, Magdeburg 39120, Germany
| | - Samuel Voss
- University of Magdeburg, Magdeburg 39106, Germany
| | | | | | | | - Neil Ashton
- The University of Manchester, Manchester M60 1QD, UK
| | | | | | | | | | | | | | - Wenyu Fu
- Beijing University of Technology, Beijing 100124, China
| | - Aike Qiao
- Beijing University of Technology, Beijing 100124, China
| | | | - Simona Hodis
- Texas A&M University, Kingsville, TX 78363
- Mayo Clinic, Rochester, MN 55905
| | | | | | | | | | | | - Kenichi Kono
- Wakayama Rosai Hospital, Wakayama 640-8505, Japan
| | - Prahlad G. Menon
- Sun Yat-sen University—Carnegie Mellon University Joint Institute of Engineering, Pittsburgh, PA 15219
| | - Priti G. Albal
- Sun Yat-sen University—Carnegie Mellon University Joint Institute of Engineering, Pittsburgh, PA 15219
| | - Otto Mierka
- University of Dortmund, Dortmund 44227, Germany
| | | | | | | | - Jan Osman
- Charité-Universitätsmedizin Berlin, Berlin 13353, Germany
| | | | | | | | | | | | | | - Susana Ramalho
- blueCAPE Lda—CAE Solutions, Milharado 2665-305, Portugal
| | - Nelson Marques
- blueCAPE Lda—CAE Solutions, Milharado 2665-305, Portugal
| | | | | | | | | | | | - Gabriel Usera
- Universidad de la República, Montevideo 11300, Uruguay
| | | | - Jianping Xiang
- University at Buffalo—State University of New York, Buffalo, NY 14203
| | - Hui Meng
- University at Buffalo—State University of New York, Buffalo, NY 14203
| | | | - Gábor Janiga
- University of Magdeburg, Magdeburg 39106, Germany
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106
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Nam HG, Yoo CM, Baek SM, Kim HK, Shin JH, Hwang MH, Jo GE, Kim KS, Cho JH, Lee SH, Kim HC, Lim CH, Choi H, Sun K. Enhancement of Mechanical Properties and Testing of Nitinol Stents in Cerebral Aneurysm Simulation Models. Artif Organs 2015; 39:E213-26. [DOI: 10.1111/aor.12564] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Hyo Geun Nam
- Department of Medical Sciences; Graduate School of Medicine; Korea University; Seoul Korea
| | - Chang Min Yoo
- Department of Medical Sciences; Graduate School of Medicine; Korea University; Seoul Korea
| | - Seoung Min Baek
- Department of Medical Sciences; Graduate School of Medicine; Korea University; Seoul Korea
| | - Han Ki Kim
- Department of Mechanical Engineering; Dankook University; Yongin Korea
| | - Jae Hee Shin
- Department of Medical Sciences; Graduate School of Medicine; Korea University; Seoul Korea
| | - Min Ho Hwang
- Department of Medical Sciences; Graduate School of Medicine; Korea University; Seoul Korea
| | - Ga Eun Jo
- Department of Medical Sciences; Graduate School of Medicine; Korea University; Seoul Korea
| | - Kyong Soo Kim
- Department of Medical Sciences; Graduate School of Medicine; Korea University; Seoul Korea
| | - Jae Hwa Cho
- College of Medicine; Radiation Applied Life Science; Seoul National University; Seoul Korea
| | - Seung Hoon Lee
- Department of Otorhinolaryngology-Head and Neck Surgery; College of Medicine; Korea University; Seoul Korea
| | - Ho Chul Kim
- Department of Radiological Science; Eulji University; Seongnam Korea
| | - Chun Hak Lim
- Department of Anesthesiology and Pain Medicine; College of Medicine; Korea University; Seoul Korea
| | - Hyuk Choi
- Department of Medical Sciences; Graduate School of Medicine; Korea University; Seoul Korea
| | - Kyung Sun
- Thoracic and Cardiovascular Surgery; College of Medicine; Korea University; Seoul Korea
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107
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Donti A, Spinardi L, Brighenti M, Faccioli L, Leoni C, Fabi M, Trossello MP, Gargiulo GD, Bonvicini M. Frequency of Intracranial Aneurysms Determined by Magnetic Resonance Angiography in Children (Mean Age 16) Having Operative or Endovascular Treatment of Coarctation of the Aorta (Mean Age 3). Am J Cardiol 2015; 116:630-3. [PMID: 26096998 DOI: 10.1016/j.amjcard.2015.05.030] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Revised: 05/07/2015] [Accepted: 05/07/2015] [Indexed: 12/14/2022]
Abstract
Coarctation of the aorta (CofA) has been associated with an increased risk of intracranial aneurysm (IA). This magnetic resonance angiography (MRA) study investigates the prevalence of IAs in 80 children treated in early life for CofA. MRA was performed at mean age of 15.7 ± 7.1 years, and surgical or endovascular treatment for CofA occurred at a mean age of 2.6 ± 4.4 years. No IA was found. In contrast with earlier findings in adult patients with late treatment for CofA, this first systematic study of very early treated patients for CofA failed to confirm the association between CofA and IAs. Our results call the abnormal developmental relation between CofA and IAs into question and suggest that modifiable risk factors like hypertension may be responsible for IA development in patients with CofA with adult diagnosis and treatment. In conclusion, our data suggest that early treatment of CofA can reduce the formation of IAs in children so as to make MRA screening less valuable in this young population.
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108
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Quantitative comparison of hemodynamics in simulated and 3D angiography models of cerebral aneurysms by use of computational fluid dynamics. Radiol Phys Technol 2015; 8:258-65. [DOI: 10.1007/s12194-015-0315-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Revised: 04/12/2015] [Accepted: 04/16/2015] [Indexed: 11/25/2022]
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109
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Weddell JC, Kwack J, Imoukhuede PI, Masud A. Hemodynamic analysis in an idealized artery tree: differences in wall shear stress between Newtonian and non-Newtonian blood models. PLoS One 2015; 10:e0124575. [PMID: 25897758 PMCID: PMC4405589 DOI: 10.1371/journal.pone.0124575] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Accepted: 03/14/2015] [Indexed: 11/19/2022] Open
Abstract
Development of many conditions and disorders, such as atherosclerosis and stroke, are dependent upon hemodynamic forces. To accurately predict and prevent these conditions and disorders hemodynamic forces must be properly mapped. Here we compare a shear-rate dependent fluid (SDF) constitutive model, based on the works by Yasuda et al in 1981, against a Newtonian model of blood. We verify our stabilized finite element numerical method with the benchmark lid-driven cavity flow problem. Numerical simulations show that the Newtonian model gives similar velocity profiles in the 2-dimensional cavity given different height and width dimensions, given the same Reynolds number. Conversely, the SDF model gave dissimilar velocity profiles, differing from the Newtonian velocity profiles by up to 25% in velocity magnitudes. This difference can affect estimation in platelet distribution within blood vessels or magnetic nanoparticle delivery. Wall shear stress (WSS) is an important quantity involved in vascular remodeling through integrin and adhesion molecule mechanotransduction. The SDF model gave a 7.3-fold greater WSS than the Newtonian model at the top of the 3-dimensional cavity. The SDF model gave a 37.7-fold greater WSS than the Newtonian model at artery walls located immediately after bifurcations in the idealized femoral artery tree. The pressure drop across arteries reveals arterial sections highly resistive to flow which correlates with stenosis formation. Numerical simulations give the pressure drop across the idealized femoral artery tree with the SDF model which is approximately 2.3-fold higher than with the Newtonian model. In atherosclerotic lesion models, the SDF model gives over 1 Pa higher WSS than the Newtonian model, a difference correlated with over twice as many adherent monocytes to endothelial cells from the Newtonian model compared to the SDF model.
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Affiliation(s)
- Jared C. Weddell
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, United States of America
- * E-mail:
| | - JaeHyuk Kwack
- Department of Civil Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, United States of America
| | - P. I. Imoukhuede
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, United States of America
| | - Arif Masud
- Department of Civil Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, United States of America
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Tanweer O, Wilson TA, Metaxa E, Riina HA, Meng H. A comparative review of the hemodynamics and pathogenesis of cerebral and abdominal aortic aneurysms: lessons to learn from each other. J Cerebrovasc Endovasc Neurosurg 2014; 16:335-49. [PMID: 25599042 PMCID: PMC4296046 DOI: 10.7461/jcen.2014.16.4.335] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2014] [Revised: 10/13/2014] [Accepted: 10/29/2014] [Indexed: 12/28/2022] Open
Abstract
OBJECTIVE Cerebral aneurysms (CAs) and abdominal aortic aneurysms (AAAs) are degenerative vascular pathologies that manifest as abnormal dilations of the arterial wall. They arise with different morphologies in different types of blood vessels under different hemodynamic conditions. Although treated as different pathologies, we examine common pathways in their hemodynamic pathogenesis in order to elucidate mechanisms of formation. MATERIALS AND METHODS A systematic review of the literature was performed. Current concepts on pathogenesis and hemodynamics were collected and compared. RESULTS CAs arise as saccular dilations on the cerebral arteries of the circle of Willis under high blood flow, high wall shear stress (WSS), and high wall shear stress gradient (WSSG) conditions. AAAs arise as fusiform dilations on the infrarenal aorta under low blood flow, low, oscillating WSS, and high WSSG conditions. While at opposite ends of the WSS spectrum, they share high WSSG, a critical factor in arterial remodeling. This alone may not be enough to initiate aneurysm formation, but may ignite a cascade of downstream events that leads to aneurysm development. Despite differences in morphology and the structure, CAs and AAAs share many histopathological and biomechanical characteristics. Endothelial cell damage, loss of elastin, and smooth muscle cell loss are universal findings in CAs and AAAs. Increased matrix metalloproteinases and other proteinases, reactive oxygen species, and inflammation also contribute to the pathogenesis of both aneurysms. CONCLUSION Our review revealed similar pathways in seemingly different pathologies. We also highlight the need for cross-disciplinary studies to aid in finding similarities between pathologies.
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Affiliation(s)
- Omar Tanweer
- Department of Neurosurgery, New York University School of Medicine, NY, United States
| | - Taylor A Wilson
- Department of Neurosurgery, New York University School of Medicine, NY, United States
| | - Eleni Metaxa
- Foundation for Research and Technology - Hellas Institute of Applied and Computational Mathematics, Crete, Greece
| | - Howard A Riina
- Department of Neurosurgery, New York University School of Medicine, NY, United States
| | - Hui Meng
- Toshiba Stroke Research Center, University at Buffalo, NY, United States. ; Department of Mechanical and Aerospace Engineering, University at Buffalo, NY, United States. ; Department of Neurosurgery, University at Buffalo, NY, United States
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Munarriz PM, Castaño-Leon AM, Cepeda S, Campollo J, Alén JF, Lagares A. Endovascular treatment of a true posterior communicating artery aneurysm. Surg Neurol Int 2014; 5:S447-50. [PMID: 25422786 PMCID: PMC4235117 DOI: 10.4103/2152-7806.143273] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Accepted: 08/22/2014] [Indexed: 11/04/2022] Open
Abstract
BACKGROUND Posterior communicating artery (PCoA) aneurysms are most commonly located at the junction of the internal carotid artery and the PCoA. "True" PCoA aneurysms, which originate from the PCoA itself, are rarely encountered. Most previously reported cases were treated surgically mainly before the endovascular option became available. CASE DESCRIPTION A 53-year-old male presented with sudden onset of right hemiparesis and aphasia. Left middle cerebral artery stroke was diagnosed. Further studies revealed a 3 mm left PCoA aneurysm arising from the PCoA itself, attached to neither the internal carotid artery nor the posterior cerebral artery. Endovascular treatment was performed and the aneurysm was coiled completely. CONCLUSION Technical advances in endovascular interventional technology have permitted an additional approach to these lesions. The possible endovascular significance of the treatment of true PCoA aneurysms is discussed.
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Affiliation(s)
- Pablo M Munarriz
- Department of Neurosurgery, "12 de Octubre" University Hospital, Complutense University of Madrid, Madrid, Spain
| | - Ana M Castaño-Leon
- Department of Neurosurgery, "12 de Octubre" University Hospital, Complutense University of Madrid, Madrid, Spain
| | - Santiago Cepeda
- Department of Neurosurgery, "12 de Octubre" University Hospital, Complutense University of Madrid, Madrid, Spain
| | - Jorge Campollo
- Division of Neuroradiology, "12 de Octubre" University Hospital, Complutense University of Madrid, Madrid, Spain
| | - Jose F Alén
- Department of Neurosurgery, "12 de Octubre" University Hospital, Complutense University of Madrid, Madrid, Spain ; Division of Neuroradiology, "12 de Octubre" University Hospital, Complutense University of Madrid, Madrid, Spain
| | - Alfonso Lagares
- Department of Neurosurgery, "12 de Octubre" University Hospital, Complutense University of Madrid, Madrid, Spain
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112
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Modeling of the acute effects of primary hypertension and hypotension on the hemodynamics of intracranial aneurysms. Ann Biomed Eng 2014; 43:207-21. [PMID: 25118666 DOI: 10.1007/s10439-014-1076-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2014] [Accepted: 07/23/2014] [Indexed: 10/24/2022]
Abstract
Hemodynamics is a risk factor in intracranial aneurysms (IA). Hypertension and pharmacologically induced hypotension are common in IA patients. This study investigates how hypertension and hypotension may influence aneurysmal hemodynamics. Images of 23 IAs at typical locations were used to build patient-specific Computational Fluid Dynamics models. The effects of hypotension and hypertension were simulated through boundary conditions by modulating the normotensive flow and pressure waveforms, in turn produced by a 1D systemic vascular model. Aneurysm location and flow pattern types were used to categorize the influence of hypotension and hypertension on relevant flow variables (velocity, pressure and wall shear stress). Results indicate that, compared to other locations, vertebrobasilar aneurysms (VBA) are more sensitive to flow changes. In VBAs, space-averaged velocity at peak systole increased by 30% in hypertension (16-21% in other locations). Flow in VBAs in hypotension decreased by 20% (10-13% in other locations). Momentum-driven hemodynamic types were also more affected by hypotension and hypertension, than shear-driven types. This study shows how patient-specific modeling can be effectively used to identify location-specific flow patterns in a clinically-relevant study, thus reinforcing the role played by modeling technologies in furthering our understanding of cardiovascular disease, and their potential in future healthcare.
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113
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Flores BC, Scott WW, Eddleman CS, Batjer HH, Rickert KL. The A1-A2 diameter ratio may influence formation and rupture potential of anterior communicating artery aneurysms. Neurosurgery 2014; 73:845-53; discussion 852-3. [PMID: 23921706 DOI: 10.1227/neu.0000000000000125] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Specific morphological factors contribute to the hemodynamics of the anterior communicating artery (AComA). No study has examined the role of the A2 segment on AComA aneurysm presence and rupture. OBJECTIVE To examine the possibility that the ratio between A1 and A2 segments (A1-2 ratio) represents an independent risk factor for presence and rupture of AComA aneurysms (AComAAs). METHODS A retrospective review of an institutional aneurysm database was performed; patients with ruptured and unruptured AComAAs were identified. Two control groups were selected: group A (posterior circulation aneurysms) and group B (patients without intracranial aneurysms or other vascular malformations). Measurements of A1 and A2 diameters were obtained from digital subtraction angiography (64.1% of 3-D rotational digital subtraction angiography), and the A1-2 ratio calculated. RESULTS From January 2009 to April 2011, 156 patients were identified (52 AComAAs, 54 control group A, and 50 control group B). Mean age at the time of presentation was 56.09 years. Compared with both control groups, patients with AComAAs had greater A1 diameter (P < .01) and A1-2 ratio (P < .001) and smaller A2 diameter (P < .01). The A1-2 ratio correlated positively with the presence of AComAAs (P < .001). Ruptured AComAAs were smaller than unruptured ones (5.91 mm vs 9.25 mm, P = .02) and associated with a higher A1-2 Ratio (P = .02). The presence of a dominant A1 did not predict AComAA rupture (P = .15). The A1-2 ratio correlated positively with the presence of ruptured AComAAs (P = .04). CONCLUSION A1-2 ratio correlates positively with the presence and rupture of AComAAs and may facilitate treatment decision in cases of small, unruptured AComAAs.
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Affiliation(s)
- Bruno C Flores
- *Department of Neurological Surgery, University of Texas Southwestern Medical Center, Dallas, Texas; ‡Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas
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The proteome of mouse cerebral arteries. J Cereb Blood Flow Metab 2014; 34:1033-46. [PMID: 24667914 PMCID: PMC4050249 DOI: 10.1038/jcbfm.2014.52] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Revised: 02/12/2014] [Accepted: 02/28/2014] [Indexed: 12/29/2022]
Abstract
The cerebral vasculature ensures proper cerebral function by transporting oxygen, nutrients, and other substances to the brain. Distribution of oxygenated blood throughout the neuroaxis takes place at the level of the circle of Willis (CW). While morphologic and functional alterations in CW arteries and its main branches have been reported in cerebrovascular and neurodegenerative diseases, accompanying changes in protein expression profiles remain largely uncharacterized. In this study, we performed proteomics to compile a novel list of proteins present in mouse CW arteries and its ramifications. Circle of Willis arteries were surgically removed from 6-month-old wild-type mice, proteins extracted and analyzed by two proteomics approaches, gel-free nanoLC-mass spectrometry (MS)/MS and gel-based GelLC-MS/MS, using nanoAcquity UPLC coupled with ESI-LTQ Orbitrap XL. The two approaches helped maximize arterial proteome coverage. Six biologic and two technical replicates were performed. In all, 2,188 proteins with at least 2 unique high-scoring peptides were identified (6,630 proteins total). Proteins were classified according to vasoactivity, blood-brain barrier specificity, tight junction and adhesion molecules, membrane transporters/channels, and extracellular matrix/basal lamina proteins. Furthermore, we compared the identified CW arterial proteome with the published brain microvascular proteome. Our database provides a vital resource for the study of CW cerebral arterial protein expression profiles in health and disease.
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Wang J, Tan HQ, Zhu YQ, Li MH, Li ZZ, Yan L, Cheng YS. Complex hemodynamic insult in combination with wall degeneration at the apex of an arterial bifurcation contributes to generation of nascent aneurysms in a canine model. AJNR Am J Neuroradiol 2014; 35:1805-12. [PMID: 24788130 DOI: 10.3174/ajnr.a3926] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE The detailed mechanisms of cerebral aneurysm generation remain unclear. Our aim was to investigate whether specific hemodynamic insult in combination with arterial wall degeneration leads to the development of aneurysms in a canine model. MATERIALS AND METHODS New branch points in the common carotid artery were created in 18 dogs. Nine animals subsequently received elastase insult at the arterial bifurcation apex (elastase-treated bifurcation group); the control bifurcation group (n=9) received saline, and 3 dogs received an elastase insult to both straight common carotid arteries (elastase-treated straight group). Angiographic and hemodynamic analysis was performed immediately and 12 and 24 weeks' postsurgery; histologic response was evaluated at 12 and 24 weeks. RESULTS Angiography revealed nascent aneurysms (mean, 3.2±0.4 mm) at the arterial bifurcation apices in 5/9 models of the elastase-treated bifurcation group (versus 0 in the control bifurcation group and elastase-treated straight group) without any observed aneurysm rupture. Histologic analysis revealed internal elastic lamina discontinuity, elastic fiber disruption, a thinner muscular layer, reduced smooth-muscle cell proliferation, increased inflammatory cell (macrophage) infiltration, and expression of matrix metalloproteinase-2 and matrix metalloproteinase-9 in the media of the elastase-treated bifurcation group compared with that in either the control bifurcation group or the elastase-treated straight group (P<.001). Hemodynamic analysis after surgery indicated that the apex experienced extremely low wall shear stress and flow velocity and the highest relative and total pressure in the elastase-treated bifurcation group, while the values returned to normal after arterial wall remodelling. CONCLUSIONS In our study, combined hemodynamic insult and arterial wall degeneration at arterial bifurcations are required for the generation of aneurysms in a canine model.
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Affiliation(s)
- J Wang
- From the Department of Diagnostic and Interventional Radiology (J.W., H.-Q.T., Y.-Q.Z., M.-H.L., L.Y., Y.-S.C.), Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
| | - H-Q Tan
- From the Department of Diagnostic and Interventional Radiology (J.W., H.-Q.T., Y.-Q.Z., M.-H.L., L.Y., Y.-S.C.), Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
| | - Y-Q Zhu
- From the Department of Diagnostic and Interventional Radiology (J.W., H.-Q.T., Y.-Q.Z., M.-H.L., L.Y., Y.-S.C.), Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
| | - M-H Li
- From the Department of Diagnostic and Interventional Radiology (J.W., H.-Q.T., Y.-Q.Z., M.-H.L., L.Y., Y.-S.C.), Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
| | - Z-Z Li
- School of Mechanical Engineering (Z.-Z.L.), Shanghai Jiao Tong University, Shanghai, China
| | - L Yan
- From the Department of Diagnostic and Interventional Radiology (J.W., H.-Q.T., Y.-Q.Z., M.-H.L., L.Y., Y.-S.C.), Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
| | - Y-S Cheng
- From the Department of Diagnostic and Interventional Radiology (J.W., H.-Q.T., Y.-Q.Z., M.-H.L., L.Y., Y.-S.C.), Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
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Karmonik C, Partovi S, Loebe M, Schmack B, Weymann A, Lumsden AB, Karck M, Ruhparwar A. Computational fluid dynamics in patients with continuous-flow left ventricular assist device support show hemodynamic alterations in the ascending aorta. J Thorac Cardiovasc Surg 2014; 147:1326-1333.e1. [DOI: 10.1016/j.jtcvs.2013.09.069] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Revised: 07/30/2013] [Accepted: 09/30/2013] [Indexed: 01/24/2023]
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117
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Trias M, Arbona A, Massó J, Miñano B, Bona C. FDA's nozzle numerical simulation challenge: non-Newtonian fluid effects and blood damage. PLoS One 2014; 9:e92638. [PMID: 24667931 PMCID: PMC3965442 DOI: 10.1371/journal.pone.0092638] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Accepted: 02/25/2014] [Indexed: 11/18/2022] Open
Abstract
Data from FDA's nozzle challenge-a study to assess the suitability of simulating fluid flow in an idealized medical device-is used to validate the simulations obtained from a numerical, finite-differences code. Various physiological indicators are computed and compared with experimental data from three different laboratories, getting a very good agreement. Special care is taken with the derivation of blood damage (hemolysis). The paper is focused on the laminar regime, in order to investigate non-Newtonian effects (non-constant fluid viscosity). The code can deal with these effects with just a small extra computational cost, improving Newtonian estimations up to a ten percent. The relevance of non-Newtonian effects for hemolysis parameters is discussed.
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Affiliation(s)
- Miquel Trias
- The Institute of Applied Computing & Community Code (IAC), University of the Balearic Islands, Palma, Spain
| | - Antonio Arbona
- The Institute of Applied Computing & Community Code (IAC), University of the Balearic Islands, Palma, Spain
- * E-mail:
| | - Joan Massó
- The Institute of Applied Computing & Community Code (IAC), University of the Balearic Islands, Palma, Spain
| | - Borja Miñano
- The Institute of Applied Computing & Community Code (IAC), University of the Balearic Islands, Palma, Spain
| | - Carles Bona
- The Institute of Applied Computing & Community Code (IAC), University of the Balearic Islands, Palma, Spain
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118
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Castaño-Leon AM, Cicuendez M, Paredes I, Alen JF, Navia P, Lagares A. Coil embolization of ruptured frontopolar artery aneurysm: Case report. Neurocirugia (Astur) 2014; 25:73-6. [DOI: 10.1016/j.neucir.2013.04.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2012] [Revised: 03/30/2013] [Accepted: 04/02/2013] [Indexed: 10/26/2022]
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119
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Factors affecting formation and rupture of intracranial saccular aneurysms. Neurosurg Rev 2013; 37:1-14. [PMID: 24306170 DOI: 10.1007/s10143-013-0501-y] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2012] [Revised: 01/31/2013] [Accepted: 08/11/2013] [Indexed: 01/19/2023]
Abstract
Unruptured intracranial aneurysms represent a decisional challenge. Treatment risks have to be balanced against an unknown probability of rupture. A better understanding of the physiopathology is the basis for a better prediction of the natural history of an individual patient. Knowledge about the possible determining factors arises from a careful comparison between ruptured versus unruptured aneurysms and from the prospective observation and analysis of unbiased series with untreated, unruptured aneurysms. The key point is the correct identification of the determining variables for the fate of a specific aneurysm in a given individual. Thus, the increased knowledge of mechanisms of formation and eventual rupture of aneurysms should provide significant clues to the identification of rupture-prone aneurysms. Factors like structural vessel wall defects, local hemodynamic stress determined also by peculiar geometric configurations, and inflammation as trigger of a wall remodeling are crucial. In this sense the study of genetic modifiers of inflammatory responses together with the computational study of the vessel tree might contribute to identify aneurysms prone to rupture. The aim of this article is to underline the value of a unifying hypothesis that merges the role of geometry, with that of hemodynamics and of genetics as concerns vessel wall structure and inflammatory pathways.
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120
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Köhler B, Gasteiger R, Preim U, Theisel H, Gutberlet M, Preim B. Semi-automatic vortex extraction in 4D PC-MRI cardiac blood flow data using line predicates. IEEE TRANSACTIONS ON VISUALIZATION AND COMPUTER GRAPHICS 2013; 19:2773-2782. [PMID: 24051844 DOI: 10.1109/tvcg.2013.189] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Cardiovascular diseases (CVD) are the leading cause of death worldwide. Their initiation and evolution depends strongly on the blood flow characteristics. In recent years, advances in 4D PC-MRI acquisition enable reliable and time-resolved 3D flow measuring, which allows a qualitative and quantitative analysis of the patient-specific hemodynamics. Currently, medical researchers investigate the relation between characteristic flow patterns like vortices and different pathologies. The manual extraction and evaluation is tedious and requires expert knowledge. Standardized, (semi-)automatic and reliable techniques are necessary to make the analysis of 4D PC-MRI applicable for the clinical routine. In this work, we present an approach for the extraction of vortex flow in the aorta and pulmonary artery incorporating line predicates. We provide an extensive comparison of existent vortex extraction methods to determine the most suitable vortex criterion for cardiac blood flow and apply our approach to ten datasets with different pathologies like coarctations, Tetralogy of Fallot and aneurysms. For two cases we provide a detailed discussion how our results are capable to complement existent diagnosis information. To ensure real-time feedback for the domain experts we implement our method completely on the GPU.
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121
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Gutierrez J, Sultan S, Bagci A, Rundek T, Alperin N, Elkind MSV, Sacco RL, Wright CB. Circle of Willis configuration as a determinant of intracranial dolichoectasia. Cerebrovasc Dis 2013; 36:446-53. [PMID: 24281350 DOI: 10.1159/000356347] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2013] [Accepted: 10/14/2013] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Circle of Willis (COW) variants might influence arterial caliber in the brain. We hypothesized that these variants would be associated with the prevalence of intracranial dolichoectasia (DE). METHODS We examined COW variants and DE in a sample of stroke-free participants (n = 436) undergoing magnetic resonance angiography (MRA) as part of a population-based study. Large intracranial arterial diameters were obtained when available; if not, the artery was defined as hypoplastic or absent according to its visibility on MRA. Subscores for the anterior and the posterior circulations were created. DE was defined as arterial diameters ≥2 SD above the population mean for that artery, adjusting for intracranial volume. Generalized linear models with a Poisson distribution were used to evaluate predictors of both absent and hypoplastic vessels, and logistic regression was used to assess the odds ratio (OR) and 95% confidence interval (95% CI) of DE depending on COW variants. RESULTS Only 44% of the sample had all 14 arteries present, 32% lacked 1 artery, 18% lacked 2 and 6% lacked 3 or more. DE of at least 1 artery was not associated with the total number of hypoplastic or absent arteries, but DE in a posterior circulation artery was weakly associated with the number of absent arteries in the posterior circulation (β coefficient = 0.36, p = 0.06). DE of at least 1 artery was more frequent in those with 1 or more absent arteries (OR 1.27, 95% CI 1.03-1.57). Posterior circulation DE was more frequent in participants with at least 1 or more absent arteries at any location (OR 1.35, 95% CI 1.02-1.78). Participants with an incomplete posterior COW were more likely to have DE in the anterior circulation (OR 1.52, 95% CI 1.01-2.33). Having an absent left anterior cerebral artery (ACA) A1 segment was associated with right ACA DE (OR 34.1, 95% CI 3.16-368.2); an absent right ACA was associated with left ACA DE (OR 14.1, 95% CI 1.69-118.28). Absence of 1 (OR 1.9, 95% CI 1.1-3.4) or 2 (OR 3.0, 95% CI 1.4-6.6) of the 2 arteries connecting the anterior to the posterior circulation was associated with basilar artery DE. CONCLUSION The COW is a pleomorphic structure that allows collateral flow to compensate for an insufficient or absent arterial component at the base of the skull. By presumed flow diversion, arteries might undergo outward remodeling. Whether this compensatory arterial dilatation is beneficial or not remains unknown.
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Affiliation(s)
- Jose Gutierrez
- Department of Neurology, Columbia University Medical Center, New York, N.Y., USA
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122
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Le WJ, Zhu YQ, Li MH, Yan L, Tan HQ, Xiao SM, Cheng YS. New method for retrospective study of hemodynamic changes before and after aneurysm formation in patients with ruptured or unruptured aneurysms. BMC Neurol 2013; 13:166. [PMID: 24195732 PMCID: PMC4228259 DOI: 10.1186/1471-2377-13-166] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2013] [Accepted: 10/28/2013] [Indexed: 11/25/2022] Open
Abstract
Background Prospective observation of hemodynamic changes before and after formation of brain aneurysms is often difficult. We used a vessel surface repair method to carry out a retrospective hemodynamic study before and after aneurysm formation in a ruptured aneurysm of the posterior communicating artery (RPcomAA) and an unruptured aneurysm of the posterior communicating artery (URPcomAA). Methods Arterial geometries obtained from three-dimensional digital subtraction angiography of cerebral angiograms were used for flow simulation by employing finite-volume modeling. Hemodynamic parameters such as wall shear stress (WSS), blood-flow velocity, streamlines, pressure, and wall shear stress gradient (WSSG) in the aneurysm sac and at the site of aneurysm formation were analyzed in each model. Results At “aneurysm” status, hemodynamic analyses at the neck, body, and dome of the aneurysm revealed the distal aneurysm neck to be subjected to the highest WSS and blood-flow velocity, whereas the aneurysm dome presented the lowest WSS and blood-flow velocity in both model types. More apparent changes in WSSG at the aneurysm dome with an inflow jet and narrowed impaction zone were revealed only in the RPcomAA. At “pre-aneurysm” status, hemodynamic analyses in both models showed that the region of aneurysm formation was subjected to extremely elevated WSS, WSSG, and blood-flow velocity. Conclusions These data suggest that hemodynamic analyses in patients with ruptured or unruptured aneurysms using the vessel surface repair method are feasible, economical, and simple. Our preliminary results indicated that the arterial wall was subjected to elevated WSS, WSSG and blood-flow velocity before aneurysm generation. However, more complicated flow patterns (often with an inflow jet or narrowed impaction zone) were more likely to be observed in ruptured aneurysm.
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Affiliation(s)
| | - Yue-Qi Zhu
- Department of Radiology, The Sixth Affiliated People's Hospital, Medical School of Shanghai Jiao Tong University, No, 600, Yi Shan Road, Shanghai 200233, China.
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Sugiyama SI, Niizuma K, Nakayama T, Shimizu H, Endo H, Inoue T, Fujimura M, Ohta M, Takahashi A, Tominaga T. Relative Residence Time Prolongation in Intracranial Aneurysms. Neurosurgery 2013; 73:767-76. [DOI: 10.1227/neu.0000000000000096] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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Schimansky S, Patel S, Rahal J, Lauric A, Malek AM. Extradural internal carotid artery caliber dysregulation is associated with cerebral aneurysms. Stroke 2013; 44:3561-4. [PMID: 24092552 DOI: 10.1161/strokeaha.113.001762] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND AND PURPOSE Flow-induced hemodynamic forces are critical in extra- and intracranial arterial caliber regulation and have been proposed to mediate intracranial aneurysm (IA) formation and rupture. We hypothesized that vascular structural control may be impaired in patients harboring brain aneurysms and sought to examine any differences in extradural internal carotid artery (ICA) caliber profiles. METHODS Ninety-six catheter 2-dimensional angiograms were divided into 3 subgroups: (1) ICA leading to IA (n=38), (2) matched contralateral ICA (n=25), and (3) ICA from nonaneurysmal controls (n=33). ICA diameter was measured proximally beyond the bulb (DProx) and distally at the extradural point of maximal dilation (DMaxDist), yielding maximal distal-to-proximal ratio (RMdp). RESULTS Unlike non-IA controls that tapered smoothly, ICAs leading to IA consistently demonstrated focal sites of abnormal dilation in the distal cervical or petrous extradural segments. RMdp was greater in ICAs leading to IA compared with non-IA controls (1.17±0.1 versus 1.0±0.08; P<0.0001). Matched-pair analysis showed RMdp to be higher in ICAs leading to IA than the corresponding contralateral ICAs (1.19±0.1 versus 1.07±0.11; P=0.001); RMdp from contralateral ICAs was greater than non-IA controls (P=0.005). Among ICAs leading to IA, women showed higher RMdp (1.11±0.12 versus 1.05±0.11; P=0.02) with no relationship to intradural IA location. CONCLUSIONS Measurements of the extradural ICA in patients harboring intradural IA suggest an association with a remote upstream abnormal vascular caliber control consistent with a diffuse flow-mediated structural dysregulation showing laterality and sex dependence.
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Affiliation(s)
- Sarah Schimansky
- From the Cerebrovascular and Endovascular Division, Department of Neurosurgery, Tufts Medical Center and Tufts University School of Medicine, Boston, MA
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Pereira VM, Brina O, Gonzalez AM, Narata AP, Ouared R, Karl-Olof L. Biology and hemodynamics of aneurismal vasculopathies. Eur J Radiol 2013; 82:1606-17. [DOI: 10.1016/j.ejrad.2012.12.012] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2012] [Revised: 12/11/2012] [Accepted: 12/13/2012] [Indexed: 10/27/2022]
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Holsworth RE, Cho YI, Weidman JJ, Sloop GD, Cyr JAS. Cardiovascular benefits of phlebotomy: relationship to changes in hemorheological variables. Perfusion 2013; 29:102-16. [DOI: 10.1177/0267659113505637] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Renewed interest in the age-old concept of “bloodletting”, a therapeutic approach practiced until as recently as the 19th century, has been stimulated by the knowledge that blood loss, such as following regular donation, is associated with significant reductions in key hemorheological variables, including whole blood viscosity (WBV), plasma viscosity, hematocrit and fibrinogen. An elevated WBV appears to be both a strong predictor of cardiovascular disease and an important factor in the development of atherosclerosis. Elevated WBV through wall shear stress is the most direct physiological parameter that influences the rupture and erosion of vulnerable plaques. In addition to WBV reduction, phlebotomy may reduce an individual’s cardiovascular risk through reductions in excessive iron, oxidative stress and inflammation. Reflecting these findings, blood donation in males has shown significant drops in the incidence of cardiovascular events, as well as in procedures such as percutaneous transluminal coronary angioplasty and coronary artery bypass grafting. Collectively, the available data on the benefits of therapeutic phlebotomy point to the importance of monitoring WBV as part of a cardiovascular risk factor, along with other risk-modifying measures, whenever an increased cardiovascular risk is detected. The development of a scanning capillary tube viscometer allows the measurement of WBV in a clinical setting, which can prove to be valuable in providing an early warning sign of an increased risk of cardiovascular disease.
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Affiliation(s)
- RE Holsworth
- Southeast Colorado Hospital, Springfield, CO, USA
| | - YI Cho
- Drexel University, Philadelphia, PA, USA
| | - J J Weidman
- Thomas Jefferson University, Philadelphia, PA, USA
| | - GD Sloop
- Benefis Hospitals, Great Falls, MT, USA
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Xiang J, Tutino VM, Snyder KV, Meng H. CFD: computational fluid dynamics or confounding factor dissemination? The role of hemodynamics in intracranial aneurysm rupture risk assessment. AJNR Am J Neuroradiol 2013; 35:1849-57. [PMID: 24029393 DOI: 10.3174/ajnr.a3710] [Citation(s) in RCA: 119] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Image-based computational fluid dynamics holds a prominent position in the evaluation of intracranial aneurysms, especially as a promising tool to stratify rupture risk. Current computational fluid dynamics findings correlating both high and low wall shear stress with intracranial aneurysm growth and rupture puzzle researchers and clinicians alike. These conflicting findings may stem from inconsistent parameter definitions, small datasets, and intrinsic complexities in intracranial aneurysm growth and rupture. In Part 1 of this 2-part review, we proposed a unifying hypothesis: both high and low wall shear stress drive intracranial aneurysm growth and rupture through mural cell-mediated and inflammatory cell-mediated destructive remodeling pathways, respectively. In the present report, Part 2, we delineate different wall shear stress parameter definitions and survey recent computational fluid dynamics studies, in light of this mechanistic heterogeneity. In the future, we expect that larger datasets, better analyses, and increased understanding of hemodynamic-biologic mechanisms will lead to more accurate predictive models for intracranial aneurysm risk assessment from computational fluid dynamics.
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Affiliation(s)
- J Xiang
- From the Toshiba Stroke and Vascular Research Center (J.X., V.M.T., K.V.S., H.M.) Departments of Neurosurgery (J.X.)
| | - V M Tutino
- From the Toshiba Stroke and Vascular Research Center (J.X., V.M.T., K.V.S., H.M.) Biomedical Engineering (V.M.T.)
| | - K V Snyder
- From the Toshiba Stroke and Vascular Research Center (J.X., V.M.T., K.V.S., H.M.)
| | - H Meng
- From the Toshiba Stroke and Vascular Research Center (J.X., V.M.T., K.V.S., H.M.) Mechanical and Aerospace Engineering (H.M.), University at Buffalo, State University of New York, Buffalo, New York.
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128
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Alfano JM, Kolega J, Natarajan SK, Xiang J, Paluch RA, Levy EI, Siddiqui AH, Meng H. Intracranial Aneurysms Occur More Frequently at Bifurcation Sites That Typically Experience Higher Hemodynamic Stresses. Neurosurgery 2013; 73:497-505. [DOI: 10.1227/neu.0000000000000016] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Abstract
BACKGROUND:
Intracranial aneurysms (IAs) occur more frequently at certain bifurcations than at others. Hemodynamic stress, which promotes aneurysm formation in animal models, also differs among bifurcations, depending on flow and vessel geometry.
OBJECTIVE:
To determine whether locations that are more likely to develop IAs experience different hemodynamic stresses that might contribute to higher IA susceptibility.
METHODS:
We characterized the hemodynamic microenvironment at 10 sites in or around the circle of Willis where IAs commonly occur and examined statistical relationships between hemodynamic factors and the tendency for a site to form IAs. The tendency for each site to develop IAs was quantified on the basis of the site distribution from systematic literature analysis of 19 reports including 26 418 aneurysms. Hemodynamic parameters for these sites were derived from image-based computational fluid dynamics of 114 cerebral bifurcations from 31 individuals. Wall shear stress and its spatial gradient were calculated in the impact zone surrounding the bifurcation apex. Linear and exponential regression analyses evaluated correlations between the tendency for IA formation and the typical hemodynamics of a site.
RESULTS:
IA susceptibility significantly correlated with the magnitudes of wall shear stress and positive wall shear stress gradient within the hemodynamic impact zone calculated for each site.
CONCLUSION:
IAs occur more frequently at cerebral bifurcations that typically experience higher hemodynamic shear stress and stronger flow acceleration, conditions previously shown to promote aneurysm initiation in animals.
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Affiliation(s)
- Jaclyn M. Alfano
- Toshiba Stroke Research Center
- Department of Mechanical and Aerospace Engineering; State University of New York, Buffalo, New York
| | - John Kolega
- Toshiba Stroke Research Center
- Department of Pathology and Anatomical Sciences; State University of New York, Buffalo, New York
| | - Sabareesh K. Natarajan
- Toshiba Stroke Research Center
- Department of Neurosurgery, State University of New York, Buffalo, New York
| | - Jianping Xiang
- Toshiba Stroke Research Center
- Department of Mechanical and Aerospace Engineering; State University of New York, Buffalo, New York
| | - Rocco A. Paluch
- Department of Pediatrics; State University of New York, Buffalo, New York
| | - Elad I. Levy
- Toshiba Stroke Research Center
- Department of Neurosurgery, State University of New York, Buffalo, New York
- Department of Radiology, State University of New York, Buffalo, New York
| | - Adnan H. Siddiqui
- Toshiba Stroke Research Center
- Department of Neurosurgery, State University of New York, Buffalo, New York
- Department of Radiology, State University of New York, Buffalo, New York
| | - Hui Meng
- Toshiba Stroke Research Center
- Department of Mechanical and Aerospace Engineering; State University of New York, Buffalo, New York
- Department of Neurosurgery, State University of New York, Buffalo, New York
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129
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Lauric A, Hippelheuser J, Cohen AD, Kadasi LM, Malek AM. Wall shear stress association with rupture status in volume matched sidewall aneurysms. J Neurointerv Surg 2013; 6:466-73. [DOI: 10.1136/neurintsurg-2013-010871] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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130
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Kadasi LM, Dent WC, Malek AM. Colocalization of thin-walled dome regions with low hemodynamic wall shear stress in unruptured cerebral aneurysms. J Neurosurg 2013; 119:172-9. [DOI: 10.3171/2013.2.jns12968] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Object
Wall shear stress (WSS) plays a role in regulating endothelial function and has been suspected in cerebral aneurysm rupture. The aim of this study was to evaluate the spatial relationship between localized thinning of the aneurysm dome and estimated hemodynamic factors, hypothesizing that a low WSS would correlate with aneurysm wall degeneration.
Methods
Steady-state computational fluid dynamics analysis was performed on 16 aneurysms in 14 patients based on rotational angiographic volumes to derive maps of WSS, its spatial gradient (WSSG), and pressure. Local dome thickness was estimated categorically based on tissue translucency from high-resolution intraoperative microscopy findings. Each computational model was oriented to match the corresponding intraoperative view and numerically sampled in thin and normal adjacent dome regions, with controls at the neck and parent vessel. The pressure differential was computed as the difference between aneurysm dome points and the mean neck pressure. Pulsatile time-dependent confirmatory analysis was carried out in 7 patients.
Results
Matched-pair analysis revealed significantly lower levels of WSS (0.381 Pa vs 0.816 Pa; p < 0.0001) in thin-walled dome areas than in adjacent baseline thickness regions. Similarly, log WSSG and log WSS × WSSG were both lower in thin regions (both p < 0.0001); multivariate logistic regression analysis identified lower WSS and higher pressure differential as independent correlates of lower wall thickness with an area under the curve of 0.80. This relationship was observed in both steady-state and time-dependent pulsatile analyses.
Conclusions
Thin-walled regions of unruptured cerebral aneurysms colocalize with low WSS, suggesting a cellular mechanotransduction link between areas of flow stasis and aneurysm wall thinning.
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Affiliation(s)
- Laith M. Kadasi
- 1Cerebrovascular and Endovascular Division, Department of Neurosurgery, Tufts Medical Center; and
- 2Tufts University School of Medicine, Boston, Massachusetts
| | - Walter C. Dent
- 1Cerebrovascular and Endovascular Division, Department of Neurosurgery, Tufts Medical Center; and
| | - Adel M. Malek
- 1Cerebrovascular and Endovascular Division, Department of Neurosurgery, Tufts Medical Center; and
- 2Tufts University School of Medicine, Boston, Massachusetts
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131
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Graziano F, Russo VM, Wang W, Khismatullin D, Ulm AJ. 3D computational fluid dynamics of a treated vertebrobasilar giant aneurysm: a multistage analysis. AJNR Am J Neuroradiol 2013; 34:1387-94. [PMID: 23306008 DOI: 10.3174/ajnr.a3373] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE The treatment of giant aneurysms of the vertebrobasilar junction remains a challenging task in neurosurgical practice, and the reference standard therapy is still under debate. Through a detailed postmortem study, we analyzed the hemodynamic factors underlying the formation and recanalization of an aneurysm located at this particular site and its anatomic configuration. METHODS An adult fixed cadaveric specimen with a known VBJ GA, characterized radiographically and treated with endovascular embolization, was studied. 3D computational fluid dynamic models were built based on the specific angioarchitecture of the specimen, and each step of the endovascular treatment was simulated. RESULTS The 3D CFD study showed an area of hemodynamic stress (high wall shear stress, high static pressure, high flow velocity) at the neck region of the aneurysm, matching the site of recanalization seen during the treatment period. CONCLUSIONS Aneurysm morphologic features, location, and patient-specific angioarchitecture are the principal factors to be considered in the management of VBJ giant aneurysms. The 3D CFD study has suggested that, in the treatment of giant aneurysms, the intra-aneurysmal environment induced by partial coil or Onyx embolization may lead to hemodynamic stress at the neck region, potentially favoring recanalization of the aneurysm.
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Affiliation(s)
- F Graziano
- Clinica Neurochirurgica, AOU G. Rodolico Universita' degli Studi di Catania, Italy.
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132
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Frueh J, Maimari N, Homma T, Bovens SM, Pedrigi RM, Towhidi L, Krams R. Systems biology of the functional and dysfunctional endothelium. Cardiovasc Res 2013; 99:334-41. [PMID: 23650287 DOI: 10.1093/cvr/cvt108] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
This review provides an overview of the effect of blood flow on endothelial cell (EC) signalling pathways, applying microarray technologies to cultured cells, and in vivo studies of normal and atherosclerotic animals. It is found that in cultured ECs, 5-10% of genes are up- or down-regulated in response to fluid flow, whereas only 3-6% of genes are regulated by varying levels of fluid flow. Of all genes, 90% are regulated by the steady part of fluid flow and 10% by pulsatile components. The associated gene profiles show high variability from experiment to experiment depending on experimental conditions, and importantly, the bioinformatical methods used to analyse the data. Despite this high variability, the current data sets can be summarized with the concept of endothelial priming. In this concept, fluid flows confer protection by an up-regulation of anti-atherogenic, anti-thrombotic, and anti-inflammatory gene signatures. Consequently, predilection sites of atherosclerosis, which are associated with low-shear stress, confer low protection for atherosclerosis and are, therefore, more sensitive to high cholesterol levels. Recent studies in intact non-atherosclerotic animals confirmed these in vitro studies, and suggest that a spatial component might be present. Despite the large variability, a few signalling pathways were consistently present in the majority of studies. These were the MAPK, the nuclear factor-κB, and the endothelial nitric oxide synthase-NO pathways.
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Affiliation(s)
- Jennifer Frueh
- Department of Bioengineering, Royal School of Mines, Imperial College London, Exhibition Road, SW7 2AZ London, UK
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133
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Sasaki T, Nagashima H, Oya F, Satoh D, Kobayashi S. Carotid artery stenting for atherosclerotic stenosis associated with non-bifurcating cervical carotid artery. Neurol Med Chir (Tokyo) 2013; 53:228-32. [PMID: 23615413 DOI: 10.2176/nmc.53.228] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A 68-year-old man presented with right cervical carotid artery stenosis manifesting as ipsilateral amaurosis fugax. Angiography showed non-bifurcating cervical carotid artery with atherosclerotic stenosis near the branching of the superior thyroid artery. Carotid artery stenting (CAS) was carried out using two balloons for embolic protection of the internal carotid artery and middle meningeal artery because the ophthalmic artery was supplied by the middle meningeal artery. No procedure-related complications or restenosis occurred after stenting. Non-bifurcating cervical carotid artery is a very rare anomaly, in which the branches of the external carotid artery directly arise from the common trunk of the carotid artery without forming a bifurcation. The present patient was successfully treated with CAS for atherosclerotic stenosis associated with non-bifurcating cervical carotid artery.
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Affiliation(s)
- Tetsuo Sasaki
- Interventional Neuroradiology Center, Aizawa Hospital, 2-5-1 Honjo, Matsumoto, Nagano 390-8510, Japan.
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134
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Meng H, Tutino VM, Xiang J, Siddiqui A. High WSS or low WSS? Complex interactions of hemodynamics with intracranial aneurysm initiation, growth, and rupture: toward a unifying hypothesis. AJNR Am J Neuroradiol 2013; 35:1254-62. [PMID: 23598838 DOI: 10.3174/ajnr.a3558] [Citation(s) in RCA: 574] [Impact Index Per Article: 52.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
SUMMARY Increasing detection of unruptured intracranial aneurysms, catastrophic outcomes from subarachnoid hemorrhage, and risks and cost of treatment necessitate defining objective predictive parameters of aneurysm rupture risk. Image-based computational fluid dynamics models have suggested associations between hemodynamics and intracranial aneurysm rupture, albeit with conflicting findings regarding wall shear stress. We propose that the "high-versus-low wall shear stress" controversy is a manifestation of the complexity of aneurysm pathophysiology, and both high and low wall shear stress can drive intracranial aneurysm growth and rupture. Low wall shear stress and high oscillatory shear index trigger an inflammatory-cell-mediated pathway, which could be associated with the growth and rupture of large, atherosclerotic aneurysm phenotypes, while high wall shear stress combined with a positive wall shear stress gradient trigger a mural-cell-mediated pathway, which could be associated with the growth and rupture of small or secondary bleb aneurysm phenotypes. This hypothesis correlates disparate intracranial aneurysm pathophysiology with the results of computational fluid dynamics in search of more reliable risk predictors.
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Affiliation(s)
- H Meng
- From the Toshiba Stroke and Vascular Research Center (H.M., V.M.T., J.X., A.S.)Departments of Mechanical and Aerospace Engineering (H.M.)Neurosurgery (H.M., J.X., A.S.)Biomedical Engineering (H.M., V.M.T.), University at Buffalo, State University of New York, Buffalo, New York.
| | - V M Tutino
- From the Toshiba Stroke and Vascular Research Center (H.M., V.M.T., J.X., A.S.)Biomedical Engineering (H.M., V.M.T.), University at Buffalo, State University of New York, Buffalo, New York
| | - J Xiang
- From the Toshiba Stroke and Vascular Research Center (H.M., V.M.T., J.X., A.S.)Neurosurgery (H.M., J.X., A.S.)
| | - A Siddiqui
- From the Toshiba Stroke and Vascular Research Center (H.M., V.M.T., J.X., A.S.)Neurosurgery (H.M., J.X., A.S.)
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135
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Jeong W, Han MH, Rhee K. Effects of framing coil shape, orientation, and thickness on intra-aneurysmal flow. Med Biol Eng Comput 2013; 51:981-90. [DOI: 10.1007/s11517-013-1073-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2012] [Accepted: 03/29/2013] [Indexed: 11/30/2022]
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136
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Cho YD, Jung KH, Roh JK, Kang HS, Han MH, Lim JW. Characteristics of intracranial aneurysms associated with extracranial carotid artery disease in South Korea. Clin Neurol Neurosurg 2013; 115:1677-81. [PMID: 23545151 DOI: 10.1016/j.clineuro.2013.03.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2012] [Revised: 02/23/2013] [Accepted: 03/10/2013] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Although it is hypothesized that inflammatory signals and/or hemodynamic stress resulting from carotid disease increase the risk of aneurysm formation and growth, a relationship between intracranial aneurysms and extracranial carotid artery disease (ECAD) has not been explored. Here, we examined the characteristics of intracranial aneurysms associated with ECAD. METHODS A total of 606 consecutive patients with stenosis of 50% or more of the proximal internal carotid artery (pICA) were enrolled. Stenosis was identified by conventional angiography between January 2003 and December 2009. We determined the prevalence of intracranial aneurysms in this population. The characteristics of the aneurysms were analyzed according to the degree and laterality of stenosis. The changes in the aneurysms were tracked for the evaluation of stability. RESULTS In 86 patients (14.2%), 120 aneurysms were detected in association with pICA stenosis. In this group, 97 were associated with unilateral pICA stenosis. The distribution of aneurysms was independent of the laterality of stenosis, but aneurysms were more prevalent in the contralateral side as the stenosis grade increased (P<0.001). All aneurysms with an imaging follow-up (28.9 ± 14.3 months) were stable, and the course was not affected by treatment of the carotid stenosis. In 23 aneurysms associated with bilateral pICA stenosis, there was only one case that increased in size during a 41-month period. CONCLUSION Intracranial aneurysms were most likely associated with ECAD, but were evenly distributed irrespective of the laterality of the stenosis. The distribution was related to the severity of the contralateral pICA stenosis. The low incidence of aneurysm growth or rupture in patients with significant ECAD indicates that these aneurysms do not require immediate intervention more than other conditions.
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Affiliation(s)
- Young Dae Cho
- Department of Radiology, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, South Korea
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137
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Impact of hemodynamics on lumen boundary displacements in abdominal aortic aneurysms by means of dynamic computed tomography and computational fluid dynamics. Biomech Model Mechanobiol 2013; 12:1263-76. [DOI: 10.1007/s10237-013-0480-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2012] [Accepted: 02/16/2013] [Indexed: 11/26/2022]
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138
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Shared associations of nonatherosclerotic, large-vessel, cerebrovascular arteriopathies. Curr Opin Neurol 2013; 26:13-28. [DOI: 10.1097/wco.0b013e32835c607f] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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139
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Arnaout OM, Rahme RJ, Aoun SG, Daou MR, Batjer HH, Bendok BR. De novo large fusiform posterior circulation intracranial aneurysm presenting with subarachnoid hemorrhage 7 years after therapeutic internal carotid artery occlusion: case report and review of the literature. Neurosurgery 2013; 71:E764-71. [PMID: 22710380 DOI: 10.1227/neu.0b013e31825fd169] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND AND IMPORTANCE Although the use of proximal artery occlusion, or hunterian ligation, for the treatment of intracranial aneurysms has decreased greatly over the past decades, this approach still finds use for certain giant and complex aneurysms. The main risks of artery sacrifice are ischemic complications but also, although rare, de novo aneurysm formation. We present here a case of de novo formation of a large fusiform basilar artery aneurysm 7 years after internal carotid artery occlusion. CLINICAL PRESENTATION A 17-year-old male patient with a history of a giant right cavernous aneurysm treated 7 years earlier with right-sided endovascular internal carotid artery occlusion presented to our institution with a thunderclap headache. At the time of initial evaluation, the patient was neurologically intact and imaging revealed a 22 × 10-mm fusiform aneurysm of the distal basilar artery with mass effect on the adjacent pons as well as a small amount of subarachnoid and intraventricular blood. Complete occlusion of the right internal carotid artery was demonstrated with retrograde filling of the right middle cerebral artery from the enlarged right posterior communicating artery. The patient was subsequently treated with hunterian occlusion of the basilar artery below anterior inferior cerebellar arteries. A superficial temporal artery to middle cerebral artery bypass was performed on the right side before this occlusion. CONCLUSION Further studies on the epidemiology of de novo aneurysms after carotid artery occlusion are warranted. Patients at higher risk of the development of intracranial aneurysms should be followed aggressively after hunterian ligation, and the possibility of an extracranial-intracranial bypass should be discussed.
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Affiliation(s)
- Omar M Arnaout
- Department of Neurological Surgery, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, USA
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140
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Cebral JR, Raschi M. Suggested connections between risk factors of intracranial aneurysms: a review. Ann Biomed Eng 2012; 41:1366-83. [PMID: 23242844 DOI: 10.1007/s10439-012-0723-0] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2012] [Accepted: 12/07/2012] [Indexed: 12/01/2022]
Abstract
The purpose of this article is to review studies of aneurysm risk factors and the suggested hypotheses that connect the different risk factors and the underlying mechanisms governing the aneurysm natural history. The result of this work suggests that at the center of aneurysm evolution there is a cycle of wall degeneration and weakening in response to changing hemodynamic loading and biomechanic stress. This progressive wall degradation drives the geometrical evolution of the aneurysm until it stabilizes or ruptures. Risk factors such as location, genetics, smoking, co-morbidities, and hypertension seem to affect different components of this cycle. However, details of these interactions or their relative importance are still not clearly understood.
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Affiliation(s)
- Juan R Cebral
- Center for Computational Fluid Dynamics, George Mason University, Fairfax, VA, USA.
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141
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Chalouhi N, Ali MS, Starke RM, Jabbour PM, Tjoumakaris SI, Gonzalez LF, Rosenwasser RH, Koch WJ, Dumont AS. Cigarette smoke and inflammation: role in cerebral aneurysm formation and rupture. Mediators Inflamm 2012; 2012:271582. [PMID: 23316103 PMCID: PMC3532877 DOI: 10.1155/2012/271582] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2012] [Accepted: 10/27/2012] [Indexed: 12/17/2022] Open
Abstract
Smoking is an established risk factor for subarachnoid hemorrhage yet the underlying mechanisms are largely unknown. Recent data has implicated a role of inflammation in the development of cerebral aneurysms. Inflammation accompanying cigarette smoke exposure may thus be a critical pathway underlying the development, progression, and rupture of cerebral aneurysms. Various constituents of the inflammatory response appear to be involved including adhesion molecules, cytokines, reactive oxygen species, leukocytes, matrix metalloproteinases, and vascular smooth muscle cells. Characterization of the molecular basis of the inflammatory response accompanying cigarette smoke exposure will provide a rational approach for future targeted therapy. In this paper, we review the current body of knowledge implicating cigarette smoke-induced inflammation in cerebral aneurysm formation/rupture and attempt to highlight important avenues for future investigation.
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Affiliation(s)
- Nohra Chalouhi
- Joseph and Marie Field Cerebrovascular Research Laboratory, Division of Neurovascular & Endovascular Surgery, Department of Neurological Surgery, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Muhammad S. Ali
- Joseph and Marie Field Cerebrovascular Research Laboratory, Division of Neurovascular & Endovascular Surgery, Department of Neurological Surgery, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Robert M. Starke
- Department of Neurological Surgery, University of Virginia School of Medicine, Charlottesville, VA 22903, USA
| | - Pascal M. Jabbour
- Joseph and Marie Field Cerebrovascular Research Laboratory, Division of Neurovascular & Endovascular Surgery, Department of Neurological Surgery, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Stavropoula I. Tjoumakaris
- Joseph and Marie Field Cerebrovascular Research Laboratory, Division of Neurovascular & Endovascular Surgery, Department of Neurological Surgery, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - L. Fernando Gonzalez
- Joseph and Marie Field Cerebrovascular Research Laboratory, Division of Neurovascular & Endovascular Surgery, Department of Neurological Surgery, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Robert H. Rosenwasser
- Joseph and Marie Field Cerebrovascular Research Laboratory, Division of Neurovascular & Endovascular Surgery, Department of Neurological Surgery, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Walter J. Koch
- Center for Translational Medicine and George Zallie and Family Laboratory for Cardiovascular Gene Therapy, Department of Medicine, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Aaron S. Dumont
- Joseph and Marie Field Cerebrovascular Research Laboratory, Division of Neurovascular & Endovascular Surgery, Department of Neurological Surgery, Thomas Jefferson University, Philadelphia, PA 19107, USA
- Division of Neurovascular & Endovascular Surgery, Department of Neurological Surgery, Thomas Jefferson University, 901 Walnut Street, 3rd Floor, Philadelphia, PA 19107, USA
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142
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Sugiyama SI, Meng H, Funamoto K, Inoue T, Fujimura M, Nakayama T, Omodaka S, Shimizu H, Takahashi A, Tominaga T. Hemodynamic Analysis of Growing Intracranial Aneurysms Arising from a Posterior Inferior Cerebellar Artery. World Neurosurg 2012; 78:462-8. [DOI: 10.1016/j.wneu.2011.09.023] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2011] [Accepted: 09/06/2011] [Indexed: 11/30/2022]
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143
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"Sit back, observe, and wait." Or is there a pharmacologic preventive treatment for cerebral aneurysms? Neurosurg Rev 2012; 36:1-9; discussion 9-10. [PMID: 23070279 DOI: 10.1007/s10143-012-0429-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2011] [Revised: 06/29/2012] [Accepted: 07/29/2012] [Indexed: 10/27/2022]
Abstract
Intracranial aneurysms (IA) are a relatively frequent vascular abnormality. The prevailing opinion is that cerebral aneurysmal disease is related to hemodynamic and genetic factors, associated with structural weakness in the arterial wall which was acquired by a specific, often unknown, event. Possibly the trigger moment of aneurysm formation may depend on the dynamic arterial growth, which is closely related to aging/atherosclerosis. In most individuals, an endovascular/microsurgical approach is possible in order to obliterate the IA. However, in a number of patients with an unruptured IA (UIA), the neurosurgeon's decision is to just "sit back, observe, and wait", based on the favorable natural history of some of the UIAs. Furthermore, some individuals need to be kept under close observation since they have a higher chance of developing IA, especially those with at least two affected first-degree relatives with an IA, subjects with polycystic kidney disease, and patients who have undergone an aneurysm intervention. In these examples prophylactic strategies should be adopted, if it is at all possible. The main question is deciding the best option of clinical treatment for these cases, when surgical approach is contraindicated, or for those subjects who are more prone to develop an IA. In the present article, we hypothetically suggest a pharmacologic form of treatment with statins, beta-adrenergic blocker agents, and/or angiotensin-converting-enzyme inhibitor/angiotensin II receptor blockers to inhibit or slow down IA formation, taking into consideration some pathophysiological aspects related to aneurysmal development, such as: hemodynamic stress, arterial wall inflammation, nitric oxide formation, and atheromatous disease.
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144
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López-Cancio E, Galán A, Dorado L, Jiménez M, Hernández M, Millán M, Reverté S, Suñol A, Barallat J, Massuet A, Alzamora MT, Dávalos A, Arenillas JF. Biological Signatures of Asymptomatic Extra- and Intracranial Atherosclerosis. Stroke 2012; 43:2712-9. [DOI: 10.1161/strokeaha.112.661702] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Elena López-Cancio
- From the Departments of Neurosciences (E.L.-C., L.D., M.J., M.H., M.M., S.R., A.S., A.D.) and Biochemistry (A.G., J.B.) and the Magnetic Resonance Unit (A.M.), Hospital Universitari Germans Trias I Pujol, Universitat Autònoma de Barcelona, Badalona, Barcelona, Spain; the Primary Healthcare Research Support Unit Metropolitana Nord, ICS-IDIAP Jordi Gol, Mataró, Barcelona, Spain (M.T.A.); and the Stroke Unit, Department of Neurology, Hospital Clínico Universitario, Valladolid, Spain (J.F.A.)
| | - Amparo Galán
- From the Departments of Neurosciences (E.L.-C., L.D., M.J., M.H., M.M., S.R., A.S., A.D.) and Biochemistry (A.G., J.B.) and the Magnetic Resonance Unit (A.M.), Hospital Universitari Germans Trias I Pujol, Universitat Autònoma de Barcelona, Badalona, Barcelona, Spain; the Primary Healthcare Research Support Unit Metropolitana Nord, ICS-IDIAP Jordi Gol, Mataró, Barcelona, Spain (M.T.A.); and the Stroke Unit, Department of Neurology, Hospital Clínico Universitario, Valladolid, Spain (J.F.A.)
| | - Laura Dorado
- From the Departments of Neurosciences (E.L.-C., L.D., M.J., M.H., M.M., S.R., A.S., A.D.) and Biochemistry (A.G., J.B.) and the Magnetic Resonance Unit (A.M.), Hospital Universitari Germans Trias I Pujol, Universitat Autònoma de Barcelona, Badalona, Barcelona, Spain; the Primary Healthcare Research Support Unit Metropolitana Nord, ICS-IDIAP Jordi Gol, Mataró, Barcelona, Spain (M.T.A.); and the Stroke Unit, Department of Neurology, Hospital Clínico Universitario, Valladolid, Spain (J.F.A.)
| | - Marta Jiménez
- From the Departments of Neurosciences (E.L.-C., L.D., M.J., M.H., M.M., S.R., A.S., A.D.) and Biochemistry (A.G., J.B.) and the Magnetic Resonance Unit (A.M.), Hospital Universitari Germans Trias I Pujol, Universitat Autònoma de Barcelona, Badalona, Barcelona, Spain; the Primary Healthcare Research Support Unit Metropolitana Nord, ICS-IDIAP Jordi Gol, Mataró, Barcelona, Spain (M.T.A.); and the Stroke Unit, Department of Neurology, Hospital Clínico Universitario, Valladolid, Spain (J.F.A.)
| | - María Hernández
- From the Departments of Neurosciences (E.L.-C., L.D., M.J., M.H., M.M., S.R., A.S., A.D.) and Biochemistry (A.G., J.B.) and the Magnetic Resonance Unit (A.M.), Hospital Universitari Germans Trias I Pujol, Universitat Autònoma de Barcelona, Badalona, Barcelona, Spain; the Primary Healthcare Research Support Unit Metropolitana Nord, ICS-IDIAP Jordi Gol, Mataró, Barcelona, Spain (M.T.A.); and the Stroke Unit, Department of Neurology, Hospital Clínico Universitario, Valladolid, Spain (J.F.A.)
| | - Mónica Millán
- From the Departments of Neurosciences (E.L.-C., L.D., M.J., M.H., M.M., S.R., A.S., A.D.) and Biochemistry (A.G., J.B.) and the Magnetic Resonance Unit (A.M.), Hospital Universitari Germans Trias I Pujol, Universitat Autònoma de Barcelona, Badalona, Barcelona, Spain; the Primary Healthcare Research Support Unit Metropolitana Nord, ICS-IDIAP Jordi Gol, Mataró, Barcelona, Spain (M.T.A.); and the Stroke Unit, Department of Neurology, Hospital Clínico Universitario, Valladolid, Spain (J.F.A.)
| | - Silvia Reverté
- From the Departments of Neurosciences (E.L.-C., L.D., M.J., M.H., M.M., S.R., A.S., A.D.) and Biochemistry (A.G., J.B.) and the Magnetic Resonance Unit (A.M.), Hospital Universitari Germans Trias I Pujol, Universitat Autònoma de Barcelona, Badalona, Barcelona, Spain; the Primary Healthcare Research Support Unit Metropolitana Nord, ICS-IDIAP Jordi Gol, Mataró, Barcelona, Spain (M.T.A.); and the Stroke Unit, Department of Neurology, Hospital Clínico Universitario, Valladolid, Spain (J.F.A.)
| | - Anna Suñol
- From the Departments of Neurosciences (E.L.-C., L.D., M.J., M.H., M.M., S.R., A.S., A.D.) and Biochemistry (A.G., J.B.) and the Magnetic Resonance Unit (A.M.), Hospital Universitari Germans Trias I Pujol, Universitat Autònoma de Barcelona, Badalona, Barcelona, Spain; the Primary Healthcare Research Support Unit Metropolitana Nord, ICS-IDIAP Jordi Gol, Mataró, Barcelona, Spain (M.T.A.); and the Stroke Unit, Department of Neurology, Hospital Clínico Universitario, Valladolid, Spain (J.F.A.)
| | - Jaume Barallat
- From the Departments of Neurosciences (E.L.-C., L.D., M.J., M.H., M.M., S.R., A.S., A.D.) and Biochemistry (A.G., J.B.) and the Magnetic Resonance Unit (A.M.), Hospital Universitari Germans Trias I Pujol, Universitat Autònoma de Barcelona, Badalona, Barcelona, Spain; the Primary Healthcare Research Support Unit Metropolitana Nord, ICS-IDIAP Jordi Gol, Mataró, Barcelona, Spain (M.T.A.); and the Stroke Unit, Department of Neurology, Hospital Clínico Universitario, Valladolid, Spain (J.F.A.)
| | - Anna Massuet
- From the Departments of Neurosciences (E.L.-C., L.D., M.J., M.H., M.M., S.R., A.S., A.D.) and Biochemistry (A.G., J.B.) and the Magnetic Resonance Unit (A.M.), Hospital Universitari Germans Trias I Pujol, Universitat Autònoma de Barcelona, Badalona, Barcelona, Spain; the Primary Healthcare Research Support Unit Metropolitana Nord, ICS-IDIAP Jordi Gol, Mataró, Barcelona, Spain (M.T.A.); and the Stroke Unit, Department of Neurology, Hospital Clínico Universitario, Valladolid, Spain (J.F.A.)
| | - Maria Teresa Alzamora
- From the Departments of Neurosciences (E.L.-C., L.D., M.J., M.H., M.M., S.R., A.S., A.D.) and Biochemistry (A.G., J.B.) and the Magnetic Resonance Unit (A.M.), Hospital Universitari Germans Trias I Pujol, Universitat Autònoma de Barcelona, Badalona, Barcelona, Spain; the Primary Healthcare Research Support Unit Metropolitana Nord, ICS-IDIAP Jordi Gol, Mataró, Barcelona, Spain (M.T.A.); and the Stroke Unit, Department of Neurology, Hospital Clínico Universitario, Valladolid, Spain (J.F.A.)
| | - Antonio Dávalos
- From the Departments of Neurosciences (E.L.-C., L.D., M.J., M.H., M.M., S.R., A.S., A.D.) and Biochemistry (A.G., J.B.) and the Magnetic Resonance Unit (A.M.), Hospital Universitari Germans Trias I Pujol, Universitat Autònoma de Barcelona, Badalona, Barcelona, Spain; the Primary Healthcare Research Support Unit Metropolitana Nord, ICS-IDIAP Jordi Gol, Mataró, Barcelona, Spain (M.T.A.); and the Stroke Unit, Department of Neurology, Hospital Clínico Universitario, Valladolid, Spain (J.F.A.)
| | - Juan Francisco Arenillas
- From the Departments of Neurosciences (E.L.-C., L.D., M.J., M.H., M.M., S.R., A.S., A.D.) and Biochemistry (A.G., J.B.) and the Magnetic Resonance Unit (A.M.), Hospital Universitari Germans Trias I Pujol, Universitat Autònoma de Barcelona, Badalona, Barcelona, Spain; the Primary Healthcare Research Support Unit Metropolitana Nord, ICS-IDIAP Jordi Gol, Mataró, Barcelona, Spain (M.T.A.); and the Stroke Unit, Department of Neurology, Hospital Clínico Universitario, Valladolid, Spain (J.F.A.)
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Chalouhi N, Ali MS, Jabbour PM, Tjoumakaris SI, Gonzalez LF, Rosenwasser RH, Koch WJ, Dumont AS. Biology of intracranial aneurysms: role of inflammation. J Cereb Blood Flow Metab 2012; 32:1659-76. [PMID: 22781330 PMCID: PMC3434628 DOI: 10.1038/jcbfm.2012.84] [Citation(s) in RCA: 361] [Impact Index Per Article: 30.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Intracranial aneurysms (IAs) linger as a potentially devastating clinical problem. Despite intense investigation, our understanding of the mechanisms leading to aneurysm development, progression and rupture remain incompletely defined. An accumulating body of evidence implicates inflammation as a critical contributor to aneurysm pathogenesis. Intracranial aneurysm formation and progression appear to result from endothelial dysfunction, a mounting inflammatory response, and vascular smooth muscle cell phenotypic modulation producing a pro-inflammatory phenotype. A later final common pathway appears to involve apoptosis of cellular constituents of the vessel wall. These changes result in degradation of the integrity of the vascular wall leading to aneurysmal dilation, progression and eventual rupture in certain aneurysms. Various aspects of the inflammatory response have been investigated as contributors to IA pathogenesis including leukocytes, complement, immunoglobulins, cytokines, and other humoral mediators. Furthermore, gene expression profiling of IA compared with control arteries has prominently featured differential expression of genes involved with immune response/inflammation. Preliminary data suggest that therapies targeting the inflammatory response may have efficacy in the future treatment of IA. Further investigation, however, is necessary to elucidate the precise role of inflammation in IA pathogenesis, which can be exploited to improve the prognosis of patients harboring IA.
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Affiliation(s)
- Nohra Chalouhi
- Joseph and Marie Field Cerebrovascular Research Laboratory, Division of Neurovascular and Endovascular Surgery, Department of Neurological Surgery, Thomas Jefferson University and Jefferson Hospital for Neuroscience, Philadelphia, Pennsylvania 19107, USA.
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146
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dos Santos MLT, Spotti AR, dos Santos RMT, Borges MA, Ferrari AF, Colli BO, Tognola WA. Giant intracranial aneurysms: morphology and clinical presentation. Neurosurg Rev 2012; 36:117-22; discussion 122. [PMID: 22791075 DOI: 10.1007/s10143-012-0407-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2011] [Revised: 04/03/2012] [Accepted: 05/20/2012] [Indexed: 11/26/2022]
Abstract
The purpose of this study was to correlate the morphology of giant intracranial aneurysms (GIA) with their clinical presentation. Eighty patients with GIA, 14 males and 66 females, were studied. Univariate and multivariate analyses were made to test the associations between morphological and clinical features. The main locations of the unruptured GIA included the carotid cavernous segment, and for the ruptured GIA, the most frequent were the carotid supraclinoid and middle cerebral arteries. There was a significant association among communicating arteries (CA) of "bad" quality and presence of thrombus and calcification (TC). The risk of rupture is 8 times higher in patients with CA of "bad" quality and 11 times higher in patients without TC. GIA are more frequent in the cavernous segment. There is a high rupture risk in the middle cerebral artery. CA of "bad" quality are associated with TC. The rupture risk is significantly higher in patients without TC.
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Affiliation(s)
- Marcio L Tostes dos Santos
- Department of Neurological Sciences, Medical School of São José do Rio Preto, São José do Rio Preto, SP, Brazil.
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147
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Obi S, Masuda H, Shizuno T, Sato A, Yamamoto K, Ando J, Abe Y, Asahara T. Fluid shear stress induces differentiation of circulating phenotype endothelial progenitor cells. Am J Physiol Cell Physiol 2012; 303:C595-606. [PMID: 22744008 DOI: 10.1152/ajpcell.00133.2012] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Endothelial progenitor cells (EPCs) are mobilized from bone marrow to peripheral blood, and contribute to angiogenesis in tissue. In the process, EPCs are exposed to shear stress generated by blood flow and tissue fluid flow. Our previous study showed that shear stress induces differentiation of mature EPCs in adhesive phenotype into mature endothelial cells and, moreover, arterial endothelial cells. In this study we investigated whether immature EPCs in a circulating phenotype differentiate into mature EPCs in response to shear stress. When floating-circulating phenotype EPCs derived from ex vivo expanded human cord blood were exposed to controlled levels of shear stress in a flow-loading device, the bioactivities of adhesion, migration, proliferation, antiapoptosis, tube formation, and differentiated type of EPC colony formation increased. The surface protein expression rate of the endothelial markers VEGF receptor 1 (VEGF-R1) and -2 (VEGF-R2), VE-cadherin, Tie2, VCAM1, integrin α(v)/β(3), and E-selectin increased in shear-stressed EPCs. The VEGF-R1, VEGF-R2, VE-cadherin, and Tie2 protein increases were dependent on the magnitude of shear stress. The mRNA levels of VEGF-R1, VEGF-R2, VE-cadherin, Tie2, endothelial nitric oxide synthase, matrix metalloproteinase 9, and VEGF increased in shear-stressed EPCs. Inhibitor analysis showed that the phosphoinositide 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) signal transduction pathway is a potent activator of adhesion, proliferation, tube formation, and differentiation in response to shear stress. Western blot analysis revealed that shear stress activated the VEGF-R2 phosphorylation in a ligand-independent manner. These results indicate that shear stress increases differentiation, adhesion, migration, proliferation, antiapoptosis, and vasculogenesis of circulating phenotype EPCs by activation of VEGF-R2 and the PI3K/Akt/mTOR signal transduction pathway.
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Affiliation(s)
- Syotaro Obi
- Department of Regenerative Medicine Science, Tokai University School of Medicine, Isehara, Japan
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148
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Gao X, Liang G, Li Z, Wei X, Wang X, Zhang H, Feng S, Lin J. Wingspan stent-assisted coiling of intracranial aneurysms with symptomatic parent artery stenosis: experience in 35 patients with mid-term follow-up results. Eur J Radiol 2012; 81:e750-6. [PMID: 22381442 DOI: 10.1016/j.ejrad.2012.01.036] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2011] [Revised: 01/09/2012] [Accepted: 01/26/2012] [Indexed: 11/26/2022]
Abstract
BACKGROUND There is a potential risk of aneurysm rupture after parent artery revascularization because of increased blood flow. The purpose of this study is to assess the efficacy and safety of Wingspan stent-assisted coil embolization in the treatment of intracranial aneurysms with symptomatic parent artery stenosis. METHODS Thirty-five consecutive patients (19 men, 16 women; age range, 48-79 years; mean age, 60.4 years) harboring 35 unruptured wide-necked or fusiform intracranial aneurysms (mean size 6.8mm; range 2.5-18 mm.) with symptomatic parent artery stenosis (mean degree 71.1%; range 50-92%) were treated with the Wingspan stent-assisted coiling. Twenty-four lesions were located in the anterior circulation and eleven in the posterior circulation. Patients were premedicated with antiplatelet therapy consisting of aspirin 300 mg and clopidogrel 75 mg for at least 3 days before the procedure. Following pre-dilatation and stent placement, a coiling microcatheter entered the aneurysm through the interstices of the stent, and then coiling was performed. After the procedure, clopidogrel 75 mg daily was recommended for an additional 30 days, and aspirin 100mg was recommended throughout follow-up. For all patients, clinical follow-up was conducted by clinic visitation, or telephone interview. Angiographic follow-up with DSA was recommended at 6 months and 1 year after the procedure. Angiography follow-up (mean time 10.6 months) was obtained in 31 cases (88.6%). The technical feasibility of the procedure, procedure-related complications, angiographic results, clinical outcome and follow-up angiography were evaluated. RESULTS In every case, technical success was achieved. The degree of stenosis was reduced from 71.1% to 17.4% after balloon angioplasty and stenting. Immediate angiography demonstrated complete occlusion in 25 cases (71.4%), neck remnant in 7 cases (20.0%), and incomplete occlusion in 3 cases (8.6%). Procedure-related morbidity occurred in two patients (5.7%), including thromboembolism (n=1) and occlusion of small penetrating arteries (n=1). At follow-up (mean time 18.3 months), two additional cases of ischemic stroke occurred. The overall frequency of any stroke, intracranial hemorrhage, or death within 30 days or ipsilateral stroke beyond 30 days was 11.4%. No rehemorrhage of treated aneurysm occurred. At angiographic follow-up, four cases demonstrated ≥ 50% in-stent restenosis (12.9%), one of which was symptomatic, and two aneurysms (6.4% of the follow-up angiograms) demonstrated recanalization. CONCLUSION We found that the Wingspan stent-assisted coil embolization was helpful in the treatment of intracranial aneurysms with parent artery stenosis.
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Affiliation(s)
- Xu Gao
- Department of Neurosurgery, The General Hospital of Shenyang Military Command, Shenyang, PR China
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149
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Hemodynamics of cerebral aneurysms: computational analyses of aneurysm progress and treatment. COMPUTATIONAL AND MATHEMATICAL METHODS IN MEDICINE 2012; 2012:782801. [PMID: 22454695 PMCID: PMC3290806 DOI: 10.1155/2012/782801] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/22/2011] [Accepted: 11/10/2011] [Indexed: 12/02/2022]
Abstract
The progression of a cerebral aneurysm involves degenerative arterial wall remodeling. Various hemodynamic parameters are suspected to be major mechanical factors related to the genesis and progression of vascular diseases. Flow alterations caused by the insertion of coils and stents for interventional aneurysm treatment may affect the aneurysm embolization process. Therefore, knowledge of hemodynamic parameters may provide physicians with an advanced understanding of aneurysm progression and rupture, as well as the effectiveness of endovascular treatments. Progress in medical imaging and information technology has enabled the prediction of flow fields in the patient-specific blood vessels using computational analysis. In this paper, recent computational hemodynamic studies on cerebral aneurysm initiation, progress, and rupture are reviewed. State-of-the-art computational aneurysmal flow analyses after coiling and stenting are also summarized. We expect the computational analysis of hemodynamics in cerebral aneurysms to provide valuable information for planning and follow-up decisions for treatment.
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150
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Omodaka S, Sugiyama SI, Inoue T, Funamoto K, Fujimura M, Shimizu H, Hayase T, Takahashi A, Tominaga T. Local Hemodynamics at the Rupture Point of Cerebral Aneurysms Determined by Computational Fluid Dynamics Analysis. Cerebrovasc Dis 2012; 34:121-9. [DOI: 10.1159/000339678] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2012] [Accepted: 05/15/2012] [Indexed: 12/13/2022] Open
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