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Boisseau W, Darsaut TE, Fahed R, Drake B, Lesiuk H, Rempel JL, Gentric JC, Ognard J, Nico L, Iancu D, Roy D, Weill A, Chagnon M, Zehr J, Lavoie P, Nguyen TN, Raymond J. Stent-Assisted Coiling in the Treatment of Unruptured Intracranial Aneurysms: A Randomized Clinical Trial. AJNR Am J Neuroradiol 2023; 44:381-389. [PMID: 36927759 PMCID: PMC10084896 DOI: 10.3174/ajnr.a7815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Accepted: 02/16/2023] [Indexed: 03/18/2023]
Abstract
BACKGROUND AND PURPOSE Stent-assisted coiling may improve angiographic results of endovascular treatment of unruptured intracranial aneurysms compared with coiling alone, but this has never been shown in a randomized trial. MATERIALS AND METHODS The Stenting in the Treatment of Aneurysm Trial was an investigator-led, parallel, randomized (1:1) trial conducted in 4 university hospitals. Patients with intracranial aneurysms at risk of recurrence, defined as large aneurysms (≥10 mm), postcoiling recurrent aneurysms, or small aneurysms with a wide neck (≥4 mm), were randomly allocated to stent-assisted coiling or coiling alone. The composite primary efficacy outcome was "treatment failure," defined as initial failure to treat the aneurysm; aneurysm rupture or retreatment during follow-up; death or dependency (mRS > 2); or an angiographic residual aneurysm adjudicated by an independent core laboratory at 12 months. The primary hypothesis (revised for slow accrual) was that stent-assisted coiling would decrease treatment failures from 33% to 15%, requiring 200 patients. Primary analyses were intent to treat. RESULTS Of 205 patients recruited between 2011 and 2021, ninety-four were allocated to stent-assisted coiling and 111 to coiling alone. The primary outcome, ascertainable in 203 patients, was reached in 28/93 patients allocated to stent-assisted coiling (30.1%; 95% CI, 21.2%-40.6%) compared with 30/110 (27.3%; 95% CI, 19.4%-36.7%) allocated to coiling alone (relative risk = 1.10; 95% CI, 0.7-1.7; P = .66). Poor clinical outcomes (mRS >2) occurred in 8/94 patients allocated to stent-assisted coiling (8.5%; 95% CI, 4.0%-16.6%) compared with 6/111 (5.4%; 95% CI, 2.2%-11.9%) allocated to coiling alone (relative risk = 1.6; 95% CI, 0.6%-4.4%; P = .38). CONCLUSIONS The STAT trial did not show stent-assisted coiling to be superior to coiling alone for wide-neck, large, or recurrent unruptured aneurysms.
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Affiliation(s)
- W Boisseau
- From the Department of Radiology (W.B., D.I., D.R., A.W., J.R.), Service of Neuroradiology, Centre Hospitalier de l'Université de Montréal, Montreal, Québec, Canada
| | - T E Darsaut
- Department of Surgery (T.E.D.), Division of Neurosurgery
| | - R Fahed
- Departments of Neurology (R.F.)
| | - B Drake
- Neurosurgery (B.D., H.L.), University of Ottawa, the Ottawa Hospital, Ottawa, Ontario, Canada
| | - H Lesiuk
- Neurosurgery (B.D., H.L.), University of Ottawa, the Ottawa Hospital, Ottawa, Ontario, Canada
| | - J L Rempel
- Department of Radiology and Diagnostic Imaging (J.L.R.), University of Alberta Hospital, Mackenzie Health Sciences Centre, Edmonton, Alberta, Canada
| | - J-C Gentric
- Department of Radiology (J.-C.G., J.O.), University Hospital of Brest, Brest, France
| | - J Ognard
- Department of Radiology (J.-C.G., J.O.), University Hospital of Brest, Brest, France
| | - L Nico
- Departement of Radiology (L.N.), Service of Interventional Neuroradiology, Centre Hospitalo-universitaire de Saint-Etienne, Saint-Etienne, France
| | - D Iancu
- From the Department of Radiology (W.B., D.I., D.R., A.W., J.R.), Service of Neuroradiology, Centre Hospitalier de l'Université de Montréal, Montreal, Québec, Canada
| | - D Roy
- From the Department of Radiology (W.B., D.I., D.R., A.W., J.R.), Service of Neuroradiology, Centre Hospitalier de l'Université de Montréal, Montreal, Québec, Canada
| | - A Weill
- From the Department of Radiology (W.B., D.I., D.R., A.W., J.R.), Service of Neuroradiology, Centre Hospitalier de l'Université de Montréal, Montreal, Québec, Canada
| | - M Chagnon
- Department of Mathematics and Statistics (M.C., J.Z.), Pavillon André-Aisenstadt, Montreal, Québec, Canada
| | - J Zehr
- Department of Mathematics and Statistics (M.C., J.Z.), Pavillon André-Aisenstadt, Montreal, Québec, Canada
| | - P Lavoie
- Department of Neurosurgery (P.L.), Centre Hospitalier Universitaire de Québec-Université Laval, Québec, Canada
| | - T N Nguyen
- Departments of Neurology (T.N.N.)
- Radiology (T.N.N.), Boston Medical Center, Boston, Massachusetts
| | - J Raymond
- From the Department of Radiology (W.B., D.I., D.R., A.W., J.R.), Service of Neuroradiology, Centre Hospitalier de l'Université de Montréal, Montreal, Québec, Canada
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Mezali F, Benmamar S, Naima K, Ameur H, Rafik O. Evaluation of stent effect and thrombosis generation with different blood rheology on an intracranial aneurysm by the Lattice Boltzmann method. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2022; 219:106757. [PMID: 35338884 DOI: 10.1016/j.cmpb.2022.106757] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 03/07/2022] [Accepted: 03/12/2022] [Indexed: 06/14/2023]
Abstract
BACKGROUND AND OBJECTIVE Treatment of intracranial aneurysms with flow-diverting stents prevents rupture by reducing blood flow and creating thrombosis within the aneurysm. This paper aims to assess the hemodynamic effect of placing stents with different struts (0, 3, 5, 7 struts) on intracranial aneurysms and to propose a simple prediction model of thrombosis zone without any further computational cost. METHOD Lattice Boltzmann method with different rheological models (Newtonian, Carreau-Yasuda, KL) of blood are used to study the hemodynamic effect of flow-diverting stents in the aneurysm. Pulsatile flow boundary conditions were applied in the inlet of the artery. The average Reynolds number was resulting Re = 111. The Lagrangian tracking of the particle was developed to assess the intra-aneurysmal blood stagnation. To predict the probable thrombose zone induced by flow-diverting stents, the shear rate threshold is utilized to determine the nodes of fluid to clot. RESULTS The results show that the flow patterns into the aneurysmal sac develop a vortex, decreasing after stent placement until disappearance for the stent with seven struts (porosity 71.4%). Velocity, shear rate, shear stress, trajectory, path length, and occlusion rate are compared before and after stent placement. These parameters decrease inversely with the porosity of the stent. The three models yield a closes result of the (velocity, shear rate, occlusion rate). Tracking the fluid-particle trajectory shows that the length of the particle paths decreases with the number of struts causing fluid to slow down and increase, consequently, the residence time into the sac. CONCLUSION The flow-diverting stents placement cause the reduction of dynamic flow within aneurysm. The reduction effect is almost the same below five struts (80% of porosity). The results show that, if our objective is restricted to estimating the hemodynamic effect, measured by (velocity, shear rate, occlusion rate), the differences between rheological behavior models are, practically, not significant, and the models can be used indifferently.
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Affiliation(s)
- Farouk Mezali
- Water Sciences Research laboratory: LRS-Eau, National Polytechnic School, El harrach, Algiers; Hydraulics department, Faculty of Technology-BP 166 M'sila 28000 Algeria.
| | - Saida Benmamar
- Water Sciences Research laboratory: LRS-Eau, National Polytechnic School, El harrach, Algiers.
| | - Khatir Naima
- Department of Technology, University Centre of Naama (Ctr Univ Naama), P.O. Box 66, Naama 45000, Algeria.
| | - Houari Ameur
- Department of Technology, University Centre of Naama (Ctr Univ Naama), P.O. Box 66, Naama 45000, Algeria.
| | - Ouared Rafik
- Water Sciences Research laboratory: LRS-Eau, National Polytechnic School, El harrach, Algiers
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Saqr KM, Rashad S, Tupin S, Niizuma K, Hassan T, Tominaga T, Ohta M. What does computational fluid dynamics tell us about intracranial aneurysms? A meta-analysis and critical review. J Cereb Blood Flow Metab 2020; 40:1021-1039. [PMID: 31213162 PMCID: PMC7181089 DOI: 10.1177/0271678x19854640] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Despite the plethora of published studies on intracranial aneurysms (IAs) hemodynamic using computational fluid dynamics (CFD), limited progress has been made towards understanding the complex physics and biology underlying IA pathophysiology. Guided by 1733 published papers, we review and discuss the contemporary IA hemodynamics paradigm established through two decades of IA CFD simulations. We have traced the historical origins of simplified CFD models which impede the progress of comprehending IA pathology. We also delve into the debate concerning the Newtonian fluid assumption used to represent blood flow computationally. We evidently demonstrate that the Newtonian assumption, used in almost 90% of studies, might be insufficient to describe IA hemodynamics. In addition, some fundamental properties of the Navier-Stokes equation are revisited in supplementary material to highlight some widely spread misconceptions regarding wall shear stress (WSS) and its derivatives. Conclusively, our study draws a roadmap for next-generation IA CFD models to help researchers investigate the pathophysiology of IAs.
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Affiliation(s)
- Khalid M Saqr
- Biomedical Flow Dynamics Laboratory, Institute of Fluid Science, Tohoku University, Sendai, Miyagi, Japan.,Department of Mechanical Engineering, College of Engineering and Technology, Arab Academy for Science, Technology and Maritime Transport, Alexandria, Egypt
| | - Sherif Rashad
- Department of Neurosurgical Engineering and Translational Neuroscience, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan.,Department of Neurosurgery, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
| | - Simon Tupin
- Biomedical Flow Dynamics Laboratory, Institute of Fluid Science, Tohoku University, Sendai, Miyagi, Japan
| | - Kuniyasu Niizuma
- Department of Neurosurgical Engineering and Translational Neuroscience, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan.,Department of Neurosurgery, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan.,Department of Neurosurgical Engineering and Translational Neuroscience, Graduate School of Biomedical Engineering, Tohoku University, Sendai, Japan
| | - Tamer Hassan
- Department of Neurosurgery, Alexandria University School of Medicine, Azarita Medical Campus, Alexandria, Egypt
| | - Teiji Tominaga
- Department of Neurosurgery, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
| | - Makoto Ohta
- Biomedical Flow Dynamics Laboratory, Institute of Fluid Science, Tohoku University, Sendai, Miyagi, Japan
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Lee JY, Cho YD, Kang HS, Han MH. Healing of Aneurysm after Treatment Using Flow Diverter Stent : Histopathological Study in Experimental Canine Carotid Side Wall Aneurysm. J Korean Neurosurg Soc 2019; 63:34-44. [PMID: 31295979 PMCID: PMC6952739 DOI: 10.3340/jkns.2019.0067] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Accepted: 04/22/2019] [Indexed: 02/06/2023] Open
Abstract
OBJECTIVE Despite widespread use of flow diverters (FDs) to treat aneurysms, the exact healing mechanism associated with FDs remains poorly understood. We aim to describe the healing process of aneurysms treated using FDs by demonstrating the histopathologic progression in a canine aneurysm model. METHODS Twenty-one side wall aneurysms were created in common carotid artery of eight dogs and treated with two different FDs. Angiographic follow-ups were done immediately after placement of the device, 4 weeks and 12 weeks. At last follow-up, the aneurysm and the device-implanted parent artery were harvested. RESULTS Histopathologic findings of aneurysms at 4 weeks follow-up showed intra-aneurysm thrombus formation in laminating fashion, and neointimal thickening at the mid-segment of aneurysm. However, there are inhomogenous findings in aneurysms treated with the same type of FD showing same angiographic outcomes. At 12 weeks, aneurysms of complete and near-complete occlusion revealed markedly shrunken aneurysm filled with organized connective tissues with thin neointima. Aneurysms of incomplete occlusion at 12 weeks showed small amount of organized thrombus around fringe neck and large empty space with thick neointmal formation. Neointimal thickness and diameter stenosis was not significantly different between the groups of FD specification and follow-up period. CONCLUSION Intra-aneurysmal thrombus formation and organization seem to be an important factor for the complete occlusion of aneurysms treated using the FD. Neointimal formation could occur along the struts of the FD independently of intra-aneurysmal thrombus formation. However, neointimal formation could not solely lead to complete aneurysm healing.
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Affiliation(s)
- Jong Young Lee
- Department of Neurosurgery, Hallym University Gangdong Sacred Heart Hospital, Hallym University College of Medicine, Seoul, Korea
| | - Young Dae Cho
- Department of Radiology, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea
| | - Hyun-Seung Kang
- Department of Neurosurgery, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea
| | - Moon Hee Han
- Department of Neurosurgery, Veterans Health Service Medical Center, Seoul, Korea
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Sadasivan C, Swartwout E, Kappel AD, Woo HH, Fiorella DJ, Lieber BB. In vitro measurement of the permeability of endovascular coils deployed in cerebral aneurysms. J Neurointerv Surg 2018; 10:896-900. [PMID: 29298858 DOI: 10.1136/neurintsurg-2017-013481] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Revised: 12/04/2017] [Accepted: 12/07/2017] [Indexed: 11/03/2022]
Abstract
BACKGROUND AND PURPOSE Aneurysm recurrence is the primary limitation of endovascular coiling treatment for cerebral aneurysms. Coiling is currently quantified by a volumetric porosity measure called packing density (pd). Blood flow through a coil mass depends on the permeability of the coil mass, and not just its pd. The permeability of coil masses has not yet been quantified. Here we measure coil permeability with a traditional falling-head permeameter modified to incorporate idealized aneurysms. METHODS Silicone replicas of idealized aneurysms were manufactured with three different aneurysm diameters (4, 5, and 8 mm). Four different coil types (Codman Trufill Orbit, Covidien Axium, Microvention Microplex 10, and Penumbra 400) were deployed into the aneurysms with a target pd of 35%. Coiled replicas were installed on a falling-head permeameter setup and the time taken for a column of fluid above the aneurysm to drop a certain height was recorded. Permeability of the samples was calculated based on a simple modification of the traditional permeameter equation to incorporate a spherical aneurysm. RESULTS The targeted 35% pd was achieved for all samples (35%±1%, P=0.91). Coil permeabilities were significantly different from each other (P<0.001) at constant pd. Microplex 10 coils had the lowest permeability of all coil types. Data suggest a trend of increasing permeability with thicker coil wire diameter (not statistically significant). CONCLUSIONS A simple in vitro setup was developed to measure the permeabilities of coil masses based on traditional permeametry. Coil permeability should be considered when evaluating the hemodynamic efficacy of coiling instead of just packing density. Coils made of thicker wires may be more permeable, and thus less effective, than coils made from thinner wires. Whether aneurysm recurrence is affected by coil wire diameter or permeability needs to be confirmed with clinical trials.
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Affiliation(s)
- Chander Sadasivan
- Department of Neurological Surgery, Stony Brook University, Stony Brook, New York, USA
| | - Erica Swartwout
- Department of Neurological Surgery, Stony Brook University, Stony Brook, New York, USA
| | - Ari D Kappel
- Department of Neurological Surgery, Stony Brook University, Stony Brook, New York, USA
| | - Henry H Woo
- Department of Neurological Surgery, Stony Brook University, Stony Brook, New York, USA
| | - David J Fiorella
- Department of Neurological Surgery, Stony Brook University, Stony Brook, New York, USA
| | - Barry B Lieber
- Department of Neurological Surgery, Stony Brook University, Stony Brook, New York, USA
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Dholakia RJ, Kappel AD, Pagano A, Woo HH, Lieber BB, Fiorella DJ, Sadasivan C. In vitro angiographic comparison of the flow-diversion performance of five neurovascular stents. Interv Neuroradiol 2017; 24:150-161. [PMID: 29239685 DOI: 10.1177/1591019917748317] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Background and purpose Data differentiating flow diversion properties of commercially available low- and high-porosity stents are limited. This in vitro study applies angiographic analysis of intra-aneurysmal flow to compare the flow-diversion performance of five neurovascular devices in idealized sidewall and bifurcation aneurysm models. Methods Five commercial devices (Enterprise, Neuroform, LVIS, FRED, and Pipeline) were implanted in silicone sidewall and bifurcation aneurysm models under physiological average flow of blood analog fluid. High-speed angiographic images were acquired pre- and post-device implantation and contrast concentration-time curves within the aneurysm were recorded. The curves were quantified with five parameters to assess changes in contrast transport, and thus aneurysm hemodynamics, due to each device. Results Inter-device flow-diversion performance was more easily distinguished in the sidewall model than the bifurcation model. There were no obvious overall statistical trends in the bifurcation parameters but the Pipeline performed marginally better than the other devices. In the sidewall geometry, overall evidence suggests that the LVIS performed better than the Neuroform and Enterprise. The Pipeline and FRED devices were statistically superior to the three stents and Pipeline was superior to FRED in all sidewall parameters evaluated. Conclusions Based on this specific set of experiments, lower-porosity flow diverters perform significantly better in reducing intra-aneurysmal flow activity than higher-porosity stents in sidewall-type geometries. The LVIS device is potentially a better flow diverter than the Neuroform and Enterprise devices, while the Pipeline is potentially better than the FRED.
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Affiliation(s)
- Ronak J Dholakia
- Department of Neurological Surgery, 12301 Stony Brook University , Stony Brook, NY, USA
| | - Ari D Kappel
- Department of Neurological Surgery, 12301 Stony Brook University , Stony Brook, NY, USA
| | - Andrew Pagano
- Department of Neurological Surgery, 12301 Stony Brook University , Stony Brook, NY, USA
| | - Henry H Woo
- Department of Neurological Surgery, 12301 Stony Brook University , Stony Brook, NY, USA
| | - Baruch B Lieber
- Department of Neurological Surgery, 12301 Stony Brook University , Stony Brook, NY, USA
| | - David J Fiorella
- Department of Neurological Surgery, 12301 Stony Brook University , Stony Brook, NY, USA
| | - Chander Sadasivan
- Department of Neurological Surgery, 12301 Stony Brook University , Stony Brook, NY, USA
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Frolov SV, Sindeev SV, Liepsch D, Balasso A. Experimental and CFD flow studies in an intracranial aneurysm model with Newtonian and non-Newtonian fluids. Technol Health Care 2017; 24:317-33. [PMID: 26835725 DOI: 10.3233/thc-161132] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND According to the clinical data, flow conditions play a major role in the genesis of intracranial aneurysms. The disorder of the flow structure is the cause of damage of the inner layer of the vessel wall, which leads to the development of cerebral aneurysms. Knowledge of the alteration of the flow field in the aneurysm region is important for treatment. OBJECTIVE The aim is to study quantitatively the flow structure in an patient-specific aneurysm model of the internal carotid artery using both experimental and computational fluid dynamics (CFD) methods with Newtonian and non-Newtonian fluids. METHODS A patient-specific geometry of aneurysm of the internal carotid artery was used. Patient data was segmented and smoothed to obtain geometrical model. An elastic true-to-scale silicone model was created with stereolithography. For initial investigation of the blood flow, the flow was visualized by adding particles into the silicone model. The precise flow velocity measurements were done using 1D Laser Doppler Anemometer with a spatial resolution of 50 μ m and a temporal resolution of 1 ms. The local velocity measurements were done at a distance of 4 mm to each other. A fluid with non-Newtonian properties was used in the experiment. The CFD simulations for unsteady-state problem were done using constructed hexahedral mesh for Newtonian and non-Newtonian fluids. RESULTS Using 1D laser Doppler Anemometer the minimum velocity magnitude at the end of systole -0.01 m/s was obtained in the aneurysm dome while the maximum velocity 1 m/s was at the center of the outlet segment. On central cross section of the aneurysm the maximum velocity value is only 20% of the average inlet velocity. The average velocity on the cross-section is only 11% of the inlet axial velocity. Using the CFD simulation the wall shear stresses for Newtonian and non-Newtonian fluid at the end of systolic phase (t= 0.25 s) were computed. The wall shear stress varies from 3.52 mPa (minimum value) to 10.21 Pa (maximum value) for the Newtonian fluid. For the non-Newtonian fluid the wall shear stress minimum is 2.94 mPa; the maximum is 9.14 Pa. The lowest value of the wall shear stress for both fluids was obtained at the dome of the aneurysm while the highest wall shear stress was at the beginning of the outlet segment. The vortex in the aneurysm region is unstable during the cardiac cycle. The clockwise rotation of the streamlines at the inlet segment for Newtonian and non-Newtonian fluid is shown. CONCLUSION The results of the present study are in agreement with the hemodynamics theory of aneurysm genesis. Low value of wall shear stress is observed at the aneurysm dome which can cause a rupture of an aneurysm.
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Affiliation(s)
- S V Frolov
- Department of Biomedical Engineering, Tambov State Technical University, Tambov, Russia
| | - S V Sindeev
- Department of Biomedical Engineering, Tambov State Technical University, Tambov, Russia
| | - D Liepsch
- Department of Mechanical Engineering, Munich University of Applied Sciences, Munich, Germany
| | - A Balasso
- Department of Neuroradiology, Klinikum Rechts der Isar, Technical University of Munich, Munich, Germany
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Babiker MH, Chun Y, Roszelle B, Hafner W, Farsani HY, Gonzalez LF, Albuquerque F, Kealey C, Levi DS, Carman GP, Frakes DH. In Vitro Investigation of a New Thin Film Nitinol-Based Neurovascular Flow Diverter. J Med Device 2016. [DOI: 10.1115/1.4033015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Fusiform and wide-neck cerebral aneurysms (CAs) can be challenging to treat with conventional endovascular or surgical approaches. Recently, flow diverters have been developed to treat these cases by diverting flow away from the aneurysm rather than occluding it. The pipeline embolization device (PED), which embodies a single-layer braided design, is best known among available flow diverters. While the device has demonstrated success in recent trials, late aneurysmal rupture after PED treatment has been a concern. More recently, a new generation of dual-layer devices has emerged that includes a novel hyperelastic thin film nitinol (HE-TFN)-covered design. In this study, we compare fluid dynamic performance between the PED and HE-TFN devices using particle image velocimetry (PIV). The PED has a pore density of 12.5–20 pores/mm2 and a porosity of 65–70%. The two HE-TFN flow diverters have pore densities of 14.75 pores/mm2 and 40 pores/mm2, and porosities of 82% and 77%, respectively. Conventional wisdom suggests that the lower porosity PED would decrease intra-aneurysmal flow to the greatest degree. However, under physiologically realistic pulsatile flow conditions, average drops in root-mean-square (RMS) velocity (VRMS) within the aneurysm of an idealized physical flow model were 42.8–73.7% for the PED and 68.9–82.7% for the HE-TFN device with the highest pore density. Interestingly, examination of collateral vessel flows in the same model also showed that the HE-TFN design allowed for greater collateral perfusion than the PED. Similar trends were observed under steady flow conditions in the idealized model. In a more clinically realistic scenario wherein an anatomical aneurysm model was investigated, the PED affected intra-aneurysmal VRMS reductions of 64.3% and 56.3% under steady and pulsatile flow conditions, respectively. In comparison, the high pore density HE-TFN device reduced intra-aneurysmal VRMS by 88% and 71.3% under steady and pulsatile flow conditions, respectively. We attribute the superior performance of the HE-TFN device to higher pore density, which may play a more important role in modifying aneurysmal fluid dynamics than the conventional flow diverter design parameter of greatest general interest, absolute porosity. Finally, the PED led to more elevated intra-aneurysmal pressures after deployment, which provides insight into a potential mechanism for late rupture following treatment with the device.
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Affiliation(s)
- M. H. Babiker
- Endovantage, LLC, Skysong, Ste. 200, 1475 N. Scottsdale Road, Scottsdale, AZ 85257 e-mail:
| | - Y. Chun
- Department of Industrial Engineering, Swanson School of Engineering, University of Pittsburgh, 1034 Benedum Hall, Pittsburgh, PA 15261
- Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, 1034 Benedum Hall, Pittsburgh, PA 15261 e-mail:
| | - B. Roszelle
- Department of Mechanical and Materials Engineering, University of Denver, 2390 S. York Street, Denver, CO 80208 e-mail:
| | - W. Hafner
- Department of Physical Medicine and Rehabilitation, University of Colorado, 12631 East 17th Avenue, Aurora, CO 80045 e-mail:
| | - H. Y. Farsani
- School of Biological and Health Systems Engineering, ECG 334, Tempe, AZ 85287-9707 e-mail:
| | - L. F. Gonzalez
- Duke University Hospital, 2301 Erwin Road, Durham, NC 27710 e-mail:
| | - F. Albuquerque
- Barrow Neurological Institute, Saint Joseph's Hospital and Medical Center, 350 W. Thomas Road, Phoenix, AZ 85013 e-mail:
| | - C. Kealey
- Business Development, NeuroSigma, Inc., 10960 Wilshire Boulevard, Suite 1910, Los Angeles, CA 90024 e-mail:
| | - D. S. Levi
- Pediatric Cardiology, Mattel Children's Hospital, UCLA, B2-427, 10833 Le Conte Avenue, Los Angeles, CA 90095-1743 e-mail:
| | - G. P. Carman
- Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, 38-137M, Engineering IV, Los Angeles, CA 90095 e-mail:
| | - D. H. Frakes
- School of Biological and Health Systems Engineering, ECG 334, Tempe, AZ 85287-9707 e-mail:
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Mallik AS, Nuss K, Kronen PW, Klein K, Karol A, von Rechenberg B, Rüfenacht DA, Wanke I, Kulcsár Z. A new-generation, low-permeability flow diverting device for treatment of saccular aneurysms. Eur Radiol 2013; 24:12-8. [PMID: 23881302 DOI: 10.1007/s00330-013-2970-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Revised: 06/18/2013] [Accepted: 06/21/2013] [Indexed: 11/25/2022]
Abstract
OBJECTIVES We report a preclinical comparative study of a 96-strand braided flow diverter. METHODS The 96-strand braided device was compared with the currently commercially available flow diverter with 48 strands. The devices were implanted across the neck of 12 elastase-induced aneurysms in New Zealand White rabbits and followed for 1 and 3 months (n = 6 respectively). Aneurysm occlusion rates, parent artery stenosis and patency of jailed branch occlusions were assessed by angiography, histology and scanning electron microscopy studies. RESULTS It was feasible to navigate and implant the 96-strand device over the aneurysm orifice in all cases. At follow-up two aneurysms in the 48-strand vs. one in the 96-strand group were not occluded. This aneurysm from the 96-strand group however had a tracheal branch arising from the sac and showed a reverse remodelling of the vascular pouch at 3 months. In the occluded aneurysms, the parent artery was always completely reconstructed and the aneurysm orifice was sealed with neointimal tissue. No in-stent stenosis or jailed branch artery occlusion was observed. CONCLUSIONS The 96-strand flow diverter proved to be safe, biocompatible and haemodynamically effective, induced stable occlusion of aneurysms and led to reverse remodelling of the parent artery. KEY POINTS • Flow diversion has been introduced to improve endovascular treatment of cerebral aneurysms • A new low-permeability flow diverter is feasible for parent artery reconstruction. • The Silk 96 flow diverter appears effective at inducing aneurysm healing. • The covered branches remained patent at follow-up.
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Affiliation(s)
- Ajit S Mallik
- Center of Applied Biotechnology and Molecular Medicine, University of Zurich, Zurich, Switzerland
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Huang Q, Xu J, Cheng J, Wang S, Wang K, Liu JM. Hemodynamic Changes by Flow Diverters in Rabbit Aneurysm Models. Stroke 2013; 44:1936-41. [PMID: 23640830 DOI: 10.1161/strokeaha.113.001202] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background and Purpose—
The effect of flow diverter (FD) on hemodynamic changes observed in aneurysms is inevitably affected by the actual structural configuration of deployed FD. We studied the resultant hemodynamic changes after implantation of FDs using computational fluid dynamic simulations based on micro–computed tomography reconstructions in rabbit aneurysm model.
Methods—
The FDs by micro–computed tomography images and vascular model based on rabbit-specific angiograms in 14 rabbits were reconstructed for computational fluid dynamic studies, and rabbit-specific inlet flow waveforms were used as boundary conditions. The occluded group (n=10) and unoccluded group (n=4) were divided according to the follow-up angiography. Hemodynamic parameters were separately evaluated for significance with respect to FD implantation and healing.
Results—
The normalized mean wall shear stress of the aneurysm sac and inflow volume were significantly reduced after FD deployment, and the relative residence time was significantly increased after treatment, without significant differences in mean pressure of aneurysm sac. When compared with the unoccluded group, the average relative residence time increment and percentage of inflow volume reduction in occluded group were higher. Additionally, the inlet of stream after FD deployment in the occluded group was more prevalent near the central region of the neck, whereas in the unoccluded group, it was more likely to occur near the proximal part of the neck.
Conclusions—
This study provided the real structural configurations of fully deployed FDs in vivo. We demonstrated the decrease of wall shear stress, inflow volume, increase of relative residence time, and change of inflow stream induced by FD implantation. The higher relative residence time increment, percentage of inflow volume reduction, and location of stream inlet near the central part of the neck may be closely related to healing.
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Affiliation(s)
- Qinghai Huang
- From the Department of Neurosurgery, Changhai Hospital, Second Military Medical University, Shanghai, China (Q.H., J.X., J.C., K.W., J.L.); and the Department of Mechanics and Engineering Science, Fudan University, Shanghai, China (S.W.)
| | - Jinyu Xu
- From the Department of Neurosurgery, Changhai Hospital, Second Military Medical University, Shanghai, China (Q.H., J.X., J.C., K.W., J.L.); and the Department of Mechanics and Engineering Science, Fudan University, Shanghai, China (S.W.)
| | - Jiyong Cheng
- From the Department of Neurosurgery, Changhai Hospital, Second Military Medical University, Shanghai, China (Q.H., J.X., J.C., K.W., J.L.); and the Department of Mechanics and Engineering Science, Fudan University, Shanghai, China (S.W.)
| | - Shengzhang Wang
- From the Department of Neurosurgery, Changhai Hospital, Second Military Medical University, Shanghai, China (Q.H., J.X., J.C., K.W., J.L.); and the Department of Mechanics and Engineering Science, Fudan University, Shanghai, China (S.W.)
| | - Kuizhong Wang
- From the Department of Neurosurgery, Changhai Hospital, Second Military Medical University, Shanghai, China (Q.H., J.X., J.C., K.W., J.L.); and the Department of Mechanics and Engineering Science, Fudan University, Shanghai, China (S.W.)
| | - Jian-Min Liu
- From the Department of Neurosurgery, Changhai Hospital, Second Military Medical University, Shanghai, China (Q.H., J.X., J.C., K.W., J.L.); and the Department of Mechanics and Engineering Science, Fudan University, Shanghai, China (S.W.)
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11
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Kulcsár Z, Göricke SL, Gizewski ER, Schlamann M, Sure U, Sandalcioglu IE, Ladd S, Mummel P, Kastrup O, Forsting M, Wanke I. Neuroform stent-assisted treatment of intracranial aneurysms: long-term follow-up study of aneurysm recurrence and in-stent stenosis rates. Neuroradiology 2013; 55:459-65. [PMID: 23358878 DOI: 10.1007/s00234-013-1143-z] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2012] [Accepted: 01/16/2013] [Indexed: 11/29/2022]
Abstract
INTRODUCTION Our purpose was to analyze the long-term evolution of wide neck cerebral aneurysms treated with stent assistance. METHODS Data of consecutive patients treated with the Neuroform stent over 9 years were retrospectively analyzed with emphasis on periprocedural complications, aneurysm occlusion grade evolution, and in-stent stenosis rates. RESULTS Altogether, 113 patients with 117 unruptured and ruptured aneurysms were subject of analysis. Mean aneurysm size was 9.4 mm, and mean neck size was 4.7 mm. Procedural thromboembolic and hemorrhagic complications affected eight (6.8%) and four cases (3.4%), respectively. Immediate complete occlusion and occlusion with residual neck was achieved in 85% of cases, which at the first follow-up of 6 months, changed to 77 and 76 % at 36 months. Aneurysms ≥10 mm showed a higher tendency of recurrence. During the overall follow-up time ranging from 1 to 9 years, an in-stent stenosis of ≥50 % was observed only in three cases, all of them being asymptomatic. CONCLUSIONS Stent-assisted coiling of wide neck aneurysms provided stable occlusion over the long-term follow-up, with very low and silent in-stent stenosis rates. Some incompletely occluded aneurysms showed a tendency of progressive occlusion; however, this was counterbalanced by the regrowth of others.
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Affiliation(s)
- Zsolt Kulcsár
- Department of Neuroradiology, Swiss Neuro Institute, Hirslanden Clinic, Zurich, Switzerland
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12
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Galal A, Bahrassa F, Dalfino JC, Boulos AS. Stent-assisted treatment of unruptured and ruptured intracranial aneurysms: clinical and angiographic outcome. Br J Neurosurg 2013; 27:607-16. [DOI: 10.3109/02688697.2012.757292] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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13
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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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14
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A Rapid and Computationally Inexpensive Method to Virtually Implant Current and Next-Generation Stents into Subject-Specific Computational Fluid Dynamics Models. Ann Biomed Eng 2011; 39:1423-37. [DOI: 10.1007/s10439-010-0238-5] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2010] [Accepted: 12/18/2010] [Indexed: 02/04/2023]
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15
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Lubicz B. Frontiers of stent-assisted aneurysm coiling. Neuroradiology 2010; 53:937-8. [PMID: 20924755 DOI: 10.1007/s00234-010-0779-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2010] [Accepted: 09/28/2010] [Indexed: 10/19/2022]
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16
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Kim YH, Xu X, Lee JS. The effect of stent porosity and strut shape on saccular aneurysm and its numerical analysis with lattice Boltzmann method. Ann Biomed Eng 2010; 38:2274-92. [PMID: 20300847 DOI: 10.1007/s10439-010-9994-5] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2009] [Accepted: 03/02/2010] [Indexed: 11/29/2022]
Abstract
The analysis of a flow pattern in cerebral aneurysms and the effect of stent strut shapes are presented in this article. The treatment of cerebral aneurisms with a porous stent has recently been proposed as a minimally invasive way to prevent rupture and favor coagulation mechanism inside the aneurism. The efficiency of stent is related to several parameters, including porosity and stent strut shapes. The goal of this article is to study the effect of the stent strut shape and porosity on the hemodynamic properties of the flow inside an aneurysm using a numerical analysis. In this study, we use the concept of flow reduction to characterize the stent efficiency. Also, we use the lattice Boltzmann method (LBM) of a non-Newtonian blood flow. To resolve the characteristics of a highly complex flow, we use an extrapolation method for the wall and stent boundary. To ease the code development and facilitate the incorporation of new physics, a scientific programming strategy based on object-oriented concepts is developed. Reduced velocity, smaller average vorticity magnitude, smaller average shear rate, and increased viscosity are observed when the proposed stent shapes and porosities are used. The rectangular stent is observed to be optimal and to decrease the magnitude of the velocity by 89.25% in the 2D model and 53.92% in the 3D model in the aneurysm sac. Our results show the role of the porosity and stent strut shape and help us to understand the characteristics of stent strut design.
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Affiliation(s)
- Yong Hyun Kim
- Department of Mechanical Engineering, Wayne State University, Detroit, MI, USA
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17
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Augsburger L, Farhat M, Reymond P, Fonck E, Kulcsar Z, Stergiopulos N, Rüfenacht DA. Effect of Flow Diverter Porosity on Intraaneurysmal Blood Flow. Clin Neuroradiol 2009; 19:204-14. [PMID: 19705075 DOI: 10.1007/s00062-009-9005-0] [Citation(s) in RCA: 105] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2009] [Accepted: 06/17/2009] [Indexed: 11/30/2022]
Affiliation(s)
- Luca Augsburger
- Laboratory of Hemodynamics and Cardiovascular Technology, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.
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18
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Augsburger L, Reymond P, Fonck E, Kulcsar Z, Farhat M, Ohta M, Stergiopulos N, Rüfenacht DA. Methodologies to assess blood flow in cerebral aneurysms: current state of research and perspectives. J Neuroradiol 2009; 36:270-7. [PMID: 19487029 DOI: 10.1016/j.neurad.2009.03.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2009] [Revised: 03/15/2009] [Accepted: 03/16/2009] [Indexed: 11/28/2022]
Abstract
With intracranial aneurysms disease bringing a weakened arterial wall segment to initiate, grow and potentially rupture an aneurysm, current understanding of vessel wall biology perceives the disease to follow the path of a dynamic evolution and increasingly recognizes blood flow as being one of the main stakeholders driving the process. Although currently mostly morphological information is used to decide on whether or not to treat a yet unruptured aneurysm, among other factors, knowledge of blood flow parameters may provide an advanced understanding of the mechanisms leading to further aneurismal growth and potential rupture. Flow patterns, velocities, pressure and their derived quantifications, such as shear and vorticity, are today accessible by direct measurements or can be calculated through computation. This paper reviews and puts into perspective current experimental methodologies and numerical approaches available for such purposes. In our view, the combination of current medical imaging standards, numerical simulation methods and endovascular treatment methods allow for thinking that flow conditions govern more than any other factor fate and treatment in cerebral aneurysms. Approaching aneurysms from this perspective improves understanding, and while requiring a personalized aneurysm management by flow assessment and flow correction, if indicated.
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Affiliation(s)
- L Augsburger
- Laboratory of Hemodynamics and Cardiovascular Technology, Ecole polytechnique fédérale de Lausanne, Ecublens, STI IB12 LHTC 1, A1 1241, Station 15, 1015 Lausanne, Vaud, Switzerland.
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19
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Eddleman CS, Hurley MC, Bendok BR, Batjer HH. Cavernous carotid aneurysms: to treat or not to treat? Neurosurg Focus 2009; 26:E4. [DOI: 10.3171/2009.2.focus0920] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Most cavernous carotid aneurysms (CCAs) are considered benign lesions, most often asymptomatic, and to have a natural history with a low risk of life-threatening complications. However, several conditions may exist in which treatment of these aneurysms should be considered. Several options are currently available regarding the management of CCAs with resultant good outcomes, namely expectant management, luminal preservation strategies with or without addressing the aneurysm directly, and Hunterian strategies with or without revascularization procedures. In this article, we discuss the sometimes difficult decision regarding whether to treat CCAs. We consider the natural history of several types of CCAs, the clinical presentation, the current modalities of CCA management and their outcomes to aid in the management of this heterogeneous group of cerebral aneurysms.
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Affiliation(s)
| | - Michael C. Hurley
- 2Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - Bernard R. Bendok
- 1Departments of Neurological Surgery and
- 2Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
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20
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Lubicz B, Bandeira A, Bruneau M, Dewindt A, Balériaux D, De Witte O. Stenting is improving and stabilizing anatomical results of coiled intracranial aneurysms. Neuroradiology 2009; 51:419-25. [PMID: 19322563 DOI: 10.1007/s00234-009-0519-6] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2008] [Accepted: 03/03/2009] [Indexed: 11/25/2022]
Affiliation(s)
- Boris Lubicz
- Department of Neuroradiology, Erasme University Hospital, Brussels, Belgium.
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21
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Stents for intracranial wide-necked aneurysms: more than mechanical protection. Neuroradiology 2008; 50:991-8. [PMID: 18807024 DOI: 10.1007/s00234-008-0460-0] [Citation(s) in RCA: 116] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2007] [Accepted: 09/02/2008] [Indexed: 10/21/2022]
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Ahlhelm F, Roth C, Kaufmann R, Schulte-Altedorneburg G, Romeike BFM, Reith W. Treatment of wide-necked intracranial aneurysms with a novel self-expanding two-zonal endovascular stent device. Neuroradiology 2007; 49:1023-8. [PMID: 17703295 DOI: 10.1007/s00234-007-0281-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2007] [Accepted: 07/02/2007] [Indexed: 11/27/2022]
Abstract
INTRODUCTION Endovascular treatment of intracerebral wide-necked aneurysms carries the risk of incomplete embolisation and recanalisation of the aneurysm as well as coil protrusion into the parent artery and embolic complications. We present preliminary results with the placement of a novel tightly braided stent across the aneurysm neck which might lead to thrombosis of these aneurysms. METHODS A bifurcation artery aneurysm was created in a male New Zealand White Rabbit. After 4 weeks, a novel highly flexible stent with a central tightly braided mesh was placed across the aneurysm neck. Diagnostic angiography was performed during the procedure and immediately after stent deployment as well as 2 and 4 weeks following stent placement. Histological analyses, including microscopic investigations for evaluating intra-aneurysmal thrombosis and proliferation of the intima, were performed after 1 month. RESULTS Intra-aneurysmal flow reduction due to stent placement was achieved as early as 45 min after deployment. Unchanged complete occlusion of the aneurysm could be observed by angiography 2 and 4 weeks post-stent deployment. Histological analysis confirmed angiographical findings of complete aneurysm occlusion and excluded significant neointimal coverage. CONCLUSION This newly designed flexible stent may offer the potential to expand endovascular treatment of wide-necked intracranial aneurysms.
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Affiliation(s)
- Frank Ahlhelm
- Clinic for Diagnostic and Interventional Neuroradiology, Saarland-University, School of Medicine, 66421 Homburg, Germany.
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23
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Fujimura N, Ohta M, Abdo G, Ylmaz H, Lovblad KO, Rüfenacht DA. Method to quantify flow reduction in aneurysmal cavities of lateral wall aneurysms produced by stent implants used for flow diversion. Interv Neuroradiol 2006; 12:197-200. [PMID: 20569631 DOI: 10.1177/15910199060120s135] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2005] [Accepted: 12/15/2005] [Indexed: 11/15/2022] Open
Abstract
SUMMARY Stent implants placed across the neck of cerebral aneurysms are capable of reducing aneurysmal flow when coils are not used for filling the aneurysms. It is important to evaluate the effects of flow reduction caused by stent implants used for the treatment of cerebral aneurysms. Subtracted vortex centers path line method (SVC method) is one of the image post processing methods employed for quantitative flow measurement. We developed a modified SVC method by employing Cinematic Angiography (25 frames/s) and digital video recording (30 frames/s) with a commercial digital camera.We successfully compared the flow effectiveness using a tubular silicon model with a sidewall aneurysm. The result suggests that our modified SVC method is useful for a comparative examination of the effect of aneurysmal flow reduction caused by stent implants.
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Affiliation(s)
- N Fujimura
- Section of Neuroradiology, Geneva University Hospital, Switzerland - Department of Neurosurgery, Kurume University School of Medicine, Japan -
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