101
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Villard C, Wågsäter D, Swedenborg J, Eriksson P, Hultgren R. Biomarkers for Abdominal Aortic Aneurysms From a Sex Perspective. ACTA ACUST UNITED AC 2012; 9:259-266.e2. [DOI: 10.1016/j.genm.2012.05.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2012] [Revised: 05/18/2012] [Accepted: 05/26/2012] [Indexed: 01/08/2023]
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102
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Bosman WMPF, Hinnen JW, Kopp WH, van der Steenhoven TJ, Kaptein BL, Koning OHJ, Hamming JF. Influence of aneurysm wall stiffness and the presence of intraluminal thrombus on the wall movement of an aneurysm - an in vitro study. Vascular 2012; 20:203-9. [PMID: 22661613 DOI: 10.1258/vasc.2011.oa0324] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The purpose of this in vitro study was to investigate the influence of aneurysm wall stiffness and of the presence of intraluminal thrombus (ILT) on aneurysm wall movement. Three latex aneurysms were used with different wall stiffness. The aneurysms, equipped with 20 tantalum markers, were attached to an in vitro circulation model. Fluoroscopic roentgenographic stereo photogrammetric analysis was used to measure marker movement during six cardiac cycles at three different systemic pressures. To investigate the influence of ILT on wall movement, we repeated the same experiment with one of the aneurysms. The aneurysm sac was then filled with one of two E-moduli differing thrombus analogues (Novalyse 8 and 20) or with perfusate as a control. It was noted that the amplitude of the wall movement (mm) increased significantly (P < 0.05) as the compliance of the wall increased. The mean amplitude of the wall movement decreased (P < 0.05) as the stiffness (E-modulus) of the ILT increased. In conclusion, ILT has a 'cushioning effect'. Wall movement (and theoretically wall stress) diminishes when the stiffness of the ILT increases. Compliance of the aneurysm wall influences wall movement. When the stiffness of the wall increases, the wall movement diminishes.
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Affiliation(s)
- W M P F Bosman
- Department of Surgery, Leiden University Medical Center, Leiden, The Netherlands.
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103
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Georgakarakos E, Georgiadis GS, Ioannou CV, Kapoulas KC, Trellopoulos G, Lazarides M. Aneurysm sac shrinkage after endovascular treatment of the aorta: Beyond sac pressure and endoleaks. Vasc Med 2012; 17:168-73. [DOI: 10.1177/1358863x11431293] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The isolation of the aneurysm sac from systemic pressure and its consequent shrinkage are considered criteria of success after endovascular repair (EVAR). However, the process of shrinkage does not solely depend on the intrasac pressure, the predictive role of which remains ambiguous. This brief review summarizes the additional pathophysiological mechanisms that regulate the biomechanical properties of the aneurysm wall and may interfere with the process of aneurysm sac shrinkage.
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Affiliation(s)
- Efstratios Georgakarakos
- Department of Vascular Surgery, ‘Demokritus’ University of Thrace, University Hospital of Alexandroupolis, Alexandroupolis, Greece
| | - George S Georgiadis
- Department of Vascular Surgery, ‘Demokritus’ University of Thrace, University Hospital of Alexandroupolis, Alexandroupolis, Greece
| | - Christos V Ioannou
- Department of Vascular Surgery, University of Crete Medical School, University Hospital of Heraklion, Heraklion, Greece
| | - Konstantinos C Kapoulas
- Department of Vascular Surgery, ‘Demokritus’ University of Thrace, University Hospital of Alexandroupolis, Alexandroupolis, Greece
| | - George Trellopoulos
- First Surgical Clinic, General Hospital ‘G. Papanikolaou’, Exohi, Thessaloniki, Greece
| | - Miltos Lazarides
- Department of Vascular Surgery, ‘Demokritus’ University of Thrace, University Hospital of Alexandroupolis, Alexandroupolis, Greece
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104
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Assessment of Abdominal Aortic Aneurysm Wall Distensibility With Electrocardiography-Gated Computed Tomography. Ann Vasc Surg 2011; 25:1036-42. [DOI: 10.1016/j.avsg.2011.05.034] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2010] [Revised: 02/28/2011] [Accepted: 05/03/2011] [Indexed: 11/19/2022]
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105
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Chow M, McDougall C, O'Kelly C, Ashforth R, Johnson E, Fiorella D. Delayed spontaneous rupture of a posterior inferior cerebellar artery aneurysm following treatment with flow diversion: a clinicopathologic study. AJNR Am J Neuroradiol 2011; 33:E46-51. [PMID: 21835950 DOI: 10.3174/ajnr.a2532] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
In this report, we present the fatal spontaneous delayed rupture of a previously unruptured large PICA aneurysm following treatment with the PED. Pathology at postmortem examination has supported the theory that intra-aneurysmal thrombus may acutely destabilize the aneurysm wall. Aneurysms with an anatomic arrangement that promote continued flow into the neck may not be optimal candidates for the flow-diversion treatment strategy.
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Affiliation(s)
- M Chow
- Division of Neurosurgery, Department of Surgery, University of Alberta, Edmonton, Alberta, Canada.
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106
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Labruto F, Blomqvist L, Swedenborg J. Imaging the Intraluminal Thrombus of Abdominal Aortic Aneurysms: Techniques, Findings, and Clinical Implications. J Vasc Interv Radiol 2011; 22:1069-75; quiz 1075. [DOI: 10.1016/j.jvir.2011.01.454] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2010] [Revised: 01/20/2011] [Accepted: 01/30/2011] [Indexed: 10/18/2022] Open
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107
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Yoshimura K, Ikeda Y, Aoki H. Innocent bystander? Intraluminal thrombus in abdominal aortic aneurysm. Atherosclerosis 2011; 218:285-6. [PMID: 21752379 DOI: 10.1016/j.atherosclerosis.2011.06.027] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2011] [Accepted: 06/15/2011] [Indexed: 11/30/2022]
Affiliation(s)
- Koichi Yoshimura
- Department of Surgery and Clinical Science, Yamaguchi University Graduate School of Medicine, Ube, Japan.
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108
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Georgakarakos E, Ioannou CV, Georgiadis GS, Kapoulas K, Schoretsanitis N, Lazarides M. Expanding Current EVAR Indications to Include Small Abdominal Aortic Aneurysms: A Glimpse of the Future. Angiology 2011; 62:500-3. [DOI: 10.1177/0003319711398651] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The traditional criterion of maximum transverse diameter is not sufficient to differentiate the small abdominal aortic aneurysms (AAAs) that are either prone to rupture or prone to enlarge rapidly. Wall stress may be a more reliable indicator with respect to these tasks. We review the importance of geometric features in rupture- or growth-predictive models and stress the need for further evaluation and validation of geometric indices. This study may lead to identifying those small AAAs that could justify early endovascular intervention.
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Affiliation(s)
- Efstratios Georgakarakos
- Department of Vascular Surgery, “Demokritos” University of Thrace, University Hospital of Alexandroupolis, Greece,
| | - Christos V. Ioannou
- Department of Vascular Surgery, University of Crete, University Hospital of Heraklion, Greece
| | - George S. Georgiadis
- Department of Vascular Surgery, “Demokritos” University of Thrace, University Hospital of Alexandroupolis, Greece
| | - Konstantinos Kapoulas
- Department of Vascular Surgery, “Demokritos” University of Thrace, University Hospital of Alexandroupolis, Greece
| | - Nikolaos Schoretsanitis
- Department of Vascular Surgery, “Demokritos” University of Thrace, University Hospital of Alexandroupolis, Greece
| | - Miltos Lazarides
- Department of Vascular Surgery, “Demokritos” University of Thrace, University Hospital of Alexandroupolis, Greece
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109
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Larsson E, Labruto F, Gasser TC, Swedenborg J, Hultgren R. Analysis of aortic wall stress and rupture risk in patients with abdominal aortic aneurysm with a gender perspective. J Vasc Surg 2011; 54:295-9. [PMID: 21397436 DOI: 10.1016/j.jvs.2010.12.053] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2010] [Revised: 12/15/2010] [Accepted: 12/15/2010] [Indexed: 02/01/2023]
Abstract
OBJECTIVE The most commonly used predictor of rupture of an abdominal aortic aneurysm (AAA) is the diameter; however, this does not estimate the true risk for each patient. Why women with AAAs have an increased growth rate, weaker aortic wall, and increased risk for rupture is yet unclear. It is likely that geometrical and biomechanical properties contribute to found gender differences. Several studies have shown that peak wall stress (PWS) and peak wall rupture risk (PWRR), predicted by a finite element (FE) analysis of AAAs derived from computed tomography (CT), is a better predictor of rupture than maximum diameter. The purpose of this study was to investigate if women with AAAs have an increased PWS and PWRR using an FE model compared to men. METHOD Fifteen men and 15 women (AAAs 4-6 cm) were included. AAA geometry was derived from CT scans, and PWS and PWRR were estimated using the FE method. Comparisons were made by t test and Mann-Whitney test. RESULTS Mean age (women 73 years old vs men 71 years old) and mean AAA diameter was similar (49.7 mm vs 50.1 mm) for women and men. PWS did not differ for women 184 and men 198 kPa. PWRR was 0.54 (0.28-0.85) for women and 0.43 (0.24-0.66) for men, P = .06. CONCLUSION This is the first analysis of stress and strength of the aneurysm wall with a gender perspective. The reported higher rupture risk for women has previously not been tested with geometrical and biomechanical properties. PWS did not differ, but the PWRR was slightly higher in women. However, the difference did not reach statistical significance, probably due to the small sample size. In summary, the results in the present study suggest that differences in biomechanical properties could be a contributing explanation for the higher rupture risk reported for female patients with AAAs.
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MESH Headings
- Aged
- Aged, 80 and over
- Aorta, Abdominal/diagnostic imaging
- Aorta, Abdominal/physiopathology
- Aortic Aneurysm, Abdominal/complications
- Aortic Aneurysm, Abdominal/diagnostic imaging
- Aortic Aneurysm, Abdominal/physiopathology
- Aortic Rupture/diagnostic imaging
- Aortic Rupture/etiology
- Aortic Rupture/physiopathology
- Aortography/methods
- Biomechanical Phenomena
- Female
- Finite Element Analysis
- Humans
- Image Interpretation, Computer-Assisted
- Male
- Middle Aged
- Models, Cardiovascular
- Retrospective Studies
- Risk Assessment
- Risk Factors
- Sex Factors
- Stress, Mechanical
- Sweden
- Tomography, X-Ray Computed
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Affiliation(s)
- Emma Larsson
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden.
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110
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Basciano C, Kleinstreuer C, Hyun S, Finol EA. A relation between near-wall particle-hemodynamics and onset of thrombus formation in abdominal aortic aneurysms. Ann Biomed Eng 2011; 39:2010-26. [PMID: 21373952 DOI: 10.1007/s10439-011-0285-6] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2010] [Accepted: 02/18/2011] [Indexed: 10/18/2022]
Abstract
A novel computational particle-hemodynamics analysis of key criteria for the onset of an intraluminal thrombus (ILT) in a patient-specific abdominal aortic aneurysm (AAA) is presented. The focus is on enhanced platelet and white blood cell residence times as well as their elevated surface-shear loads in near-wall regions of the AAA sac. The generalized results support the hypothesis that a patient's AAA geometry and associated particle-hemodynamics have the potential to entrap activated blood particles, which will play a role in the onset of ILT. Although the ILT history of only a single patient was considered, the modeling and simulation methodology provided allow for the development of an efficient computational tool to predict the onset of ILT formation in complex patient-specific cases.
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Affiliation(s)
- C Basciano
- Physics-Based Computing Group, Southeast Division, Applied Research Associates, Raleigh, NC 27615, USA
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111
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Magnetic and contrast properties of labeled platelets for magnetomotive optical coherence tomography. Biophys J 2011; 99:2374-83. [PMID: 20923673 DOI: 10.1016/j.bpj.2010.08.007] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2010] [Revised: 07/29/2010] [Accepted: 08/05/2010] [Indexed: 01/22/2023] Open
Abstract
This article introduces a new functional imaging paradigm that uses optical coherence tomography (OCT) to detect rehydrated, lyophilized platelets (RL platelets) that are in the preclinical trial stage and contain superparamagnetic iron oxides (SPIOs) approved by the U.S. Food and Drug Administration. Platelets are highly functional blood cells that detect and adhere to sites of vascular endothelial damage by forming primary hemostatic plugs. By applying magnetic gradient forces, induced nanoscale displacements (magnetomotion) of the SPIO-RL platelets are detected as optical phase shifts in OCT. In this article, we characterize the iron content and magnetic properties of SPIO-RL platelets, construct a model to predict their magnetomotion in a tissue medium, and demonstrate OCT imaging in tissue phantoms and ex vivo pig arteries. Tissue phantoms containing SPIO-RL platelets exhibited >3 dB contrast/noise ratio at ≥1.5 × 10(9) platelets/cm(3). OCT imaging was performed on ex vivo porcine arteries after infusion of SPIO-RL platelets, and specific contrast was obtained on an artery that was surface-damaged (P < 10(-6)). This may enable new technologies for in vivo monitoring of the adherence of SPIO-RL platelets to sites of bleeding and vascular damage, which is broadly applicable for assessing trauma and cardiovascular diseases.
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112
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Davis CA. Computed tomography for the diagnosis and management of abdominal aortic aneurysms. Surg Clin North Am 2010; 91:185-93. [PMID: 21184908 DOI: 10.1016/j.suc.2010.10.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Computed tomography (CT) is useful in the detection and diagnosis of abdominal aortic aneurysms (AAA). Rupture risk can be assessed by accurately measuring diameter, tortuosity, thrombus extent, and wall stress. CT can aid in accurately determining anatomic variants as well as AAA etiology. Evaluation for surgical intervention is made by close examination of AAA morphology and specific anatomic features.
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Affiliation(s)
- Clark A Davis
- Department of General and Vascular Surgery, Gundersen Lutheran Health System, 1900 South Avenue C05-001, La Crosse, WI 54601, USA.
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113
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Martin AJ, Hetts SW, Dillon WP, Higashida RT, Halbach V, Dowd CF, Lawton MT, Saloner D. MR imaging of partially thrombosed cerebral aneurysms: characteristics and evolution. AJNR Am J Neuroradiol 2010; 32:346-51. [PMID: 21087941 DOI: 10.3174/ajnr.a2298] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE A comprehensive evaluation of aneurysmal morphometry requires appreciation of both the vascular lumen and the intraluminal thrombus. MR imaging methods can both evaluate the lumen and directly image the vessel wall. We investigated the ability of T1-weighted, T2-weighted, and steady-state MR imaging techniques to delineate thrombus morphology and reveal changes with time. MATERIALS AND METHODS Nine patients with fusiform basilar or intracranial vertebral artery aneurysms that contained intraluminal thrombus were studied with MR imaging. All patients underwent at least 2 imaging sessions, which were separated by 4-22 months. Analysis of signal intensity to determine the mean signal intensity from thrombus, blood, CSF, and brain in matched regions was performed. Aneurysm maximal diameter and cross-sectional area were determined with and without thrombus. RESULTS Thrombus was identified on all image sequences, and its general appearance was consistent between imaging sessions. Thrombus produced the highest and most consistent signal intensities with T1-weighted and steady-state techniques, though the latter showed superior contrast between luminal blood and thrombus. Heterogeneity within clot was evident in 4/9 of patients, with peripheral hyperintensity being a common feature. CONCLUSIONS Steady-state imaging was found to be superior to T1- and T2-weighted imaging for delineating and characterizing intraluminal thrombus within aneurysms. The imaging characteristics of intraluminal thrombus proved to be very consistent for long periods. Assessment of overall aneurysm size, including thrombosed portions, permits more accurate evaluation of aneurysm growth and concomitantly may permit more informed clinical decision-making with regard to the timing and need for aneurysm treatment.
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Affiliation(s)
- A J Martin
- Department of Radiology, University of California, San Francisco, 94143, USA.
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114
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Speelman L, Hellenthal F, Pulinx B, Bosboom E, Breeuwer M, van Sambeek M, van de Vosse F, Jacobs M, Wodzig W, Schurink G. The Influence of Wall Stress on AAA Growth and Biomarkers. Eur J Vasc Endovasc Surg 2010; 39:410-6. [DOI: 10.1016/j.ejvs.2009.12.021] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2009] [Accepted: 12/19/2009] [Indexed: 10/20/2022]
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