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Cayron AF, Morel S, Allémann E, Bijlenga P, Kwak BR. Imaging of intracranial aneurysms in animals: a systematic review of modalities. Neurosurg Rev 2023; 46:56. [PMID: 36786880 PMCID: PMC9928939 DOI: 10.1007/s10143-023-01953-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 11/28/2022] [Accepted: 01/23/2023] [Indexed: 02/15/2023]
Abstract
Intracranial aneurysm (IA) animal models are paramount to study IA pathophysiology and to test new endovascular treatments. A number of in vivo imaging modalities are available to characterize IAs at different stages of development in these animal models. This review describes existing in vivo imaging techniques used so far to visualize IAs in animal models. We systematically searched for studies containing in vivo imaging of induced IAs in animal models in PubMed and SPIE Digital library databases between 1 January 1945 and 13 July 2022. A total of 170 studies were retrieved and reviewed in detail, and information on the IA animal model, the objective of the study, and the imaging modality used was collected. A variety of methods to surgically construct or endogenously induce IAs in animals were identified, and 88% of the reviewed studies used surgical methods. The large majority of IA imaging in animals was performed for 4 reasons: basic research for IA models, testing of new IA treatment modalities, research on IA in vivo imaging of IAs, and research on IA pathophysiology. Six different imaging techniques were identified: conventional catheter angiography, computed tomography angiography, magnetic resonance angiography, hemodynamic imaging, optical coherence tomography, and fluorescence imaging. This review presents and discusses the advantages and disadvantages of all in vivo IA imaging techniques used in animal models to help future IA studies finding the most appropriate IA imaging modality and animal model to answer their research question.
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Affiliation(s)
- Anne F Cayron
- Department of Pathology and Immunology, Faculty of Medicine, University of Geneva, Rue Michel-Servet 1, CH-1211, Geneva, Switzerland
- Geneva Center for Inflammation Research, Faculty of Medicine, University of Geneva, Geneva, Switzerland
- School of Pharmaceutical Sciences, University of Geneva, Geneva, Switzerland
- Institute of Pharmaceutical Sciences of Western Switzerland, University of Geneva, Geneva, Switzerland
| | - Sandrine Morel
- Department of Pathology and Immunology, Faculty of Medicine, University of Geneva, Rue Michel-Servet 1, CH-1211, Geneva, Switzerland
- Geneva Center for Inflammation Research, Faculty of Medicine, University of Geneva, Geneva, Switzerland
- Department of Clinical Neurosciences - Division of Neurosurgery, Geneva University Hospitals and Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Eric Allémann
- School of Pharmaceutical Sciences, University of Geneva, Geneva, Switzerland
- Institute of Pharmaceutical Sciences of Western Switzerland, University of Geneva, Geneva, Switzerland
| | - Philippe Bijlenga
- Department of Clinical Neurosciences - Division of Neurosurgery, Geneva University Hospitals and Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Brenda R Kwak
- Department of Pathology and Immunology, Faculty of Medicine, University of Geneva, Rue Michel-Servet 1, CH-1211, Geneva, Switzerland.
- Geneva Center for Inflammation Research, Faculty of Medicine, University of Geneva, Geneva, Switzerland.
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Wang X, Chan V, Corridon PR. Acellular Tissue-Engineered Vascular Grafts from Polymers: Methods, Achievements, Characterization, and Challenges. Polymers (Basel) 2022; 14:4825. [PMID: 36432950 PMCID: PMC9695055 DOI: 10.3390/polym14224825] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 11/03/2022] [Accepted: 11/03/2022] [Indexed: 11/11/2022] Open
Abstract
Extensive and permanent damage to the vasculature leading to different pathogenesis calls for developing innovative therapeutics, including drugs, medical devices, and cell therapies. Innovative strategies to engineer bioartificial/biomimetic vessels have been extensively exploited as an effective replacement for vessels that have seriously malfunctioned. However, further studies in polymer chemistry, additive manufacturing, and rapid prototyping are required to generate highly engineered vascular segments that can be effectively integrated into the existing vasculature of patients. One recently developed approach involves designing and fabricating acellular vessel equivalents from novel polymeric materials. This review aims to assess the design criteria, engineering factors, and innovative approaches for the fabrication and characterization of biomimetic macro- and micro-scale vessels. At the same time, the engineering correlation between the physical properties of the polymer and biological functionalities of multiscale acellular vascular segments are thoroughly elucidated. Moreover, several emerging characterization techniques for probing the mechanical properties of tissue-engineered vascular grafts are revealed. Finally, significant challenges to the clinical transformation of the highly promising engineered vessels derived from polymers are identified, and unique perspectives on future research directions are presented.
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Affiliation(s)
- Xinyu Wang
- Department of Biomedical Engineering and Healthcare Engineering Innovation Center, Khalifa University, Abu Dhabi P.O. Box 127788, United Arab Emirates
- Department of Immunology and Physiology, College of Medicine and Health Sciences, Khalifa University, Abu Dhabi P.O. Box 127788, United Arab Emirates
| | - Vincent Chan
- Department of Biomedical Engineering and Healthcare Engineering Innovation Center, Khalifa University, Abu Dhabi P.O. Box 127788, United Arab Emirates
| | - Peter R. Corridon
- Department of Biomedical Engineering and Healthcare Engineering Innovation Center, Khalifa University, Abu Dhabi P.O. Box 127788, United Arab Emirates
- Department of Immunology and Physiology, College of Medicine and Health Sciences, Khalifa University, Abu Dhabi P.O. Box 127788, United Arab Emirates
- Center for Biotechnology, Khalifa University, Abu Dhabi P.O. Box 127788, United Arab Emirates
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Mühl-Benninghaus R, Abboud R, Ding A, Krajewski S, Simgen A, Tomori T, Bomberg H, Yilmaz U, Brochhausen C, Reith W, Cattaneo G. Preclinical Evaluation of the Accero Stent: Flow Remodelling Effect on Aneurysm, Vessel Reaction and Side Branch Patency. Cardiovasc Intervent Radiol 2019; 42:1786-1794. [DOI: 10.1007/s00270-019-02345-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Accepted: 09/19/2019] [Indexed: 10/25/2022]
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Gester K, Lüchtefeld I, Büsen M, Sonntag SJ, Linde T, Steinseifer U, Cattaneo G. In Vitro Evaluation of Intra-Aneurysmal, Flow-Diverter-Induced Thrombus Formation: A Feasibility Study. AJNR Am J Neuroradiol 2015; 37:490-6. [PMID: 26450536 DOI: 10.3174/ajnr.a4555] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Accepted: 08/10/2015] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Intracranial aneurysm treatment by flow diverters aims at triggering intra-aneurysmal thrombosis. By combining in vitro blood experiments with particle imaging velocimetry measurements, we investigated the time-resolved thrombus formation triggered by flow diverters. MATERIALS AND METHODS Two test setups were built, 1 for particle imaging velocimetry and 1 for blood experiments, both generating the same pulsatile flow and including a silicone aneurysm model. Tests without flow diverters and with 2 different flow-diverter sizes (diameter: 4.5 and 4.0 mm) were performed. In the blood experiments, the intra-aneurysmal flow was monitored by using Doppler sonography. The experiments were stopped at 3 different changes of the spatial extent of the signal. RESULTS No thrombus was detected in the aneurysm model without the flow diverter. Otherwise, thrombi were observed in all aneurysm models with flow diverters. The thrombi grew from the proximal side of the aneurysm neck with fibrin threads connected to the flow diverter and extending across the aneurysm. The thrombus resulting from the 4.0-mm flow diverter grew along the aneurysm wall as a solid and organized thrombus, which correlates with the slower velocities near the wall detected by particle imaging velocimetry. The thrombus that evolved by using the 4.5-mm flow diverter showed no identifiable growing direction. The entire thrombus presumably resulted from stagnation of blood and correlates with the central vortex detected by particle imaging velocimetry. CONCLUSIONS We showed the feasibility of in vitro investigation of time-resolved thrombus formation in the presence of flow diverters.
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Affiliation(s)
- K Gester
- From the Department of Cardiovascular Engineering (K.G., I.L., M.B., S.J.S., T.L., U.S.), Institute of Applied Medical Engineering, Helmholtz Institute-RWTH Aachen University, Aachen, Germany
| | - I Lüchtefeld
- From the Department of Cardiovascular Engineering (K.G., I.L., M.B., S.J.S., T.L., U.S.), Institute of Applied Medical Engineering, Helmholtz Institute-RWTH Aachen University, Aachen, Germany
| | - M Büsen
- From the Department of Cardiovascular Engineering (K.G., I.L., M.B., S.J.S., T.L., U.S.), Institute of Applied Medical Engineering, Helmholtz Institute-RWTH Aachen University, Aachen, Germany
| | - S J Sonntag
- From the Department of Cardiovascular Engineering (K.G., I.L., M.B., S.J.S., T.L., U.S.), Institute of Applied Medical Engineering, Helmholtz Institute-RWTH Aachen University, Aachen, Germany
| | - T Linde
- From the Department of Cardiovascular Engineering (K.G., I.L., M.B., S.J.S., T.L., U.S.), Institute of Applied Medical Engineering, Helmholtz Institute-RWTH Aachen University, Aachen, Germany
| | - U Steinseifer
- From the Department of Cardiovascular Engineering (K.G., I.L., M.B., S.J.S., T.L., U.S.), Institute of Applied Medical Engineering, Helmholtz Institute-RWTH Aachen University, Aachen, Germany
| | - G Cattaneo
- Acandis GmbH & Co KG (G.C.), Pforzheim, Germany
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Singh C, Wong CS, Wang X. Medical Textiles as Vascular Implants and Their Success to Mimic Natural Arteries. J Funct Biomater 2015; 6:500-25. [PMID: 26133386 PMCID: PMC4598668 DOI: 10.3390/jfb6030500] [Citation(s) in RCA: 99] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2015] [Revised: 06/18/2015] [Accepted: 06/18/2015] [Indexed: 02/06/2023] Open
Abstract
Vascular implants belong to a specialised class of medical textiles. The basic purpose of a vascular implant (graft and stent) is to act as an artificial conduit or substitute for a diseased artery. However, the long-term healing function depends on its ability to mimic the mechanical and biological behaviour of the artery. This requires a thorough understanding of the structure and function of an artery, which can then be translated into a synthetic structure based on the capabilities of the manufacturing method utilised. Common textile manufacturing techniques, such as weaving, knitting, braiding, and electrospinning, are frequently used to design vascular implants for research and commercial purposes for the past decades. However, the ability to match attributes of a vascular substitute to those of a native artery still remains a challenge. The synthetic implants have been found to cause disturbance in biological, biomechanical, and hemodynamic parameters at the implant site, which has been widely attributed to their structural design. In this work, we reviewed the design aspect of textile vascular implants and compared them to the structure of a natural artery as a basis for assessing the level of success as an implant. The outcome of this work is expected to encourage future design strategies for developing improved long lasting vascular implants.
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Affiliation(s)
- Charanpreet Singh
- Australian Future Fibres Research and Innovation Centre, Institute for Frontier Materials, Deakin University, Geelong, VIC 3216, Australia.
| | - Cynthia S Wong
- Australian Future Fibres Research and Innovation Centre, Institute for Frontier Materials, Deakin University, Geelong, VIC 3216, Australia.
| | - Xungai Wang
- Australian Future Fibres Research and Innovation Centre, Institute for Frontier Materials, Deakin University, Geelong, VIC 3216, Australia.
- School of Textile Science and Engineering, Wuhan Textile University, Wuhan 430073, China.
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Qureshi AI, Qureshi MH, Mohindroo T, Khan AA, Dingmann K, Sherr GT, Suri MFK. Flow-independent dynamics in aneurysms: intra-aneurysm pressure measurements following complete flow cessation in internal carotid artery aneurysms. J Endovasc Ther 2014; 21:861-6. [PMID: 25453892 DOI: 10.1583/14-4789r.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
PURPOSE To determine if complete flow obliteration by covered stents reduces intra-aneurysm pressures in internal carotid artery (ICA) aneurysms. METHODS A single lumen microcatheter was placed into the aneurysm sac prior to covered stent deployment in 3 patients and connected to a pressure monitoring system. The intra-aneurysm pressure was continuously monitored, and readings were recorded prior to and immediately after stent deployment and at 5-minute intervals up to 20 minutes after stent placement. Complete occlusion of flow into the aneurysms was confirmed by carotid angiography. RESULTS There was no change in mean pressure within the aneurysm before and immediately after stent placement (80 mmHg) in any patient, nor was there a change in waveform of the intra-aneurysm pressure recording. The average of intra-aneurysm pressures among the 3 patients was higher (99 mmHg) at 10 and 15 minutes after stent placement. In 2 patients, the microcatheter was retracted into the parent arterial lumen; no difference in pressure was noted. CONCLUSION Our observations suggest no change in the pressures within the aneurysm after complete flow cessation (flow-independent). These findings may assist clinicians in better understanding aneurysm hemodynamics and rupture after covered stent deployment.
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Affiliation(s)
- Adnan I Qureshi
- Zeenat Qureshi Stroke Institute, and Department of Cerebrovascular Diseases, CentraCare Health, St. Cloud, Minnesota, USA
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Abstract
The principle of flow diversion is the newest endovascular concept for the treatment of intracranial aneurysms. These flow-diverting devices have a narrow mesh system and lead to aneurysm occlusion by reconstructing the vessel wall and by changing the hemodynamic blood flow within the aneurysm. The aim of flow diverting devices is the treatment of complex intracranial aneurysms, such as wide-necked, fusiform and giant aneurysms, which in the past could only be treated interventionally with a relatively high risk. The purpose of this article is to give an overview of this new alternative in the treatment of intracranial aneurysms.
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A novel approach for connecting temporal-ontologies with blood flow simulations. J Biomed Inform 2013; 46:470-9. [DOI: 10.1016/j.jbi.2013.03.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2012] [Revised: 03/03/2013] [Accepted: 03/04/2013] [Indexed: 11/23/2022]
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Effects of metal coverage rate of flow diversion device on neointimal growth at side branch ostium and stented artery: an animal experiment in rabbit abdominal aorta. Neuroradiology 2011; 54:849-55. [PMID: 22170078 DOI: 10.1007/s00234-011-0984-6] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2011] [Accepted: 11/21/2011] [Indexed: 10/14/2022]
Abstract
INTRODUCTION To access the effect of actual metal coverage rate (MCR) on neointimal growth at covered side branch ostium and stented artery after implantation of a flow diversion device. METHODS Flow diverters (FDs) were implanted into abdominal aortas of 20 New Zealand rabbits. Four weeks and three months after FD implantation, the patency of side branches covered by the devices was assessed by angiography. The animals were sacrificed after angiography at 3 months postsurgery. The local actual MCR was measured under microscope and calculated. The extent of neointimal coverage at the ostia of branches and the neointima within the stent were examined by histology and scanning electron microscopy. RESULTS No side branch occlusion was noted, either immediately after implantation or at follow-ups. At 3 months after implantation, the intimal coverage of branch ostia caused by a 30-40% MCR was not significantly different from that caused by an MCR ≤ 30% (p = 0.792), but it was significantly lower than that caused by an MCR ≥ 40% (p = 0.021). Neointimal thickness in the stented abdominal aorta was positively correlated to MCR (r = 0.523, p = 0.001). The neointima was composed predominantly of smooth muscle cells and collagen fibers. CONCLUSION The actual MCR exhibited remarkable differences once FD was implanted in vivo. Significantly more intimal coverage at the side branch ostia could be induced when MCR was ≥40%. The neointimal thickness within the stent was positively correlated to device MCR.
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Struffert T, Ott S, Adamek E, Schwarz M, Engelhorn T, Kloska S, Deuerling-Zheng Y, Doerfler A. Flat-detector computed tomography in the assessment of intracranial stents: comparison with multi detector CT and conventional angiography in a new animal model. Eur Radiol 2011; 21:1779-87. [PMID: 21365196 DOI: 10.1007/s00330-011-2093-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2010] [Accepted: 01/08/2011] [Indexed: 11/28/2022]
Affiliation(s)
- Tobias Struffert
- Department of Neuroradiology, University of Erlangen-Nuremberg, Schwabachanlage 6, 91054 Erlangen, Germany.
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Kwon SC, Ding YH, Dai D, Kadirvel R, Lewis DA, Kallmes DF. Preliminary results of the luna aneurysm embolization system in a rabbit model: a new intrasaccular aneurysm occlusion device. AJNR Am J Neuroradiol 2010; 32:602-6. [PMID: 21163876 DOI: 10.3174/ajnr.a2314] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Recent advances in endovascular devices have been aimed at providing high density, mesh-like metallic materials across the aneurysm neck, in place of coil technology. Therefore our aim was to report the in vivo preclinical performance of a self-expanding intrasaccular embolization device. MATERIALS AND METHODS Elastase-induced aneurysms were created in 12 rabbits. Each aneurysm was embolized with a Luna AES. DSA was performed preimplantation; 5, 10, and 30 minutes postimplantation; and at 1 month in 12 rabbits and at 3 months in 8 rabbits. Early postimplantation intra-aneurysmal flow was graded as unchanged, moderately diminished, or completely absent. One- and 3-month DSAs were graded by using a 3-point scale (complete, near-complete, or incomplete occlusion). Aneurysms were harvested for gross and microscopic histologic evaluation at 1 month (n = 4) and at 3 months (n = 8). Tissues within the aneurysm dome and across the aneurysm neck were assessed by using HE staining. RESULTS Ten (83%) of 12 aneurysms demonstrated complete cessation of flow within 30 minutes of device implantation. At 1-month follow-up, 10 (83%) of 12 aneurysms were completely occluded. At 3 months, 7 of 8 (88%) aneurysms remained completely occluded. One-month gross examination in 4 rabbits demonstrated that membranous tissue completely covered the device in 3 subjects (75%). Microscopic examination showed that 3 aneurysms had loose connective tissue filling the aneurysm cavity. Three-month gross and microscopic examinations demonstrated membranous tissue completely covering the device, loose connective tissue filling the aneurysm cavity, and neointima formation crossing the aneurysm neck in 8 of 8 (100.0%) subjects. CONCLUSIONS The Luna AES achieved high rates of complete angiographic occlusion and showed promising histologic findings in the rabbit aneurysm model.
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Affiliation(s)
- S C Kwon
- Department of Neurosurgery, Ulsan University Hospital, University of Ulsan College of Medicine, Republic of Korea
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Augsburger L, Reymond P, Rufenacht DA, Stergiopulos N. Intracranial Stents Being Modeled as a Porous Medium: Flow Simulation in Stented Cerebral Aneurysms. Ann Biomed Eng 2010; 39:850-63. [DOI: 10.1007/s10439-010-0200-6] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2010] [Accepted: 10/20/2010] [Indexed: 11/30/2022]
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Dorn F, Niedermeyer F, Balasso A, Liepsch D, Liebig T. The effect of stents on intra-aneurysmal hemodynamics: in vitro evaluation of a pulsatile sidewall aneurysm using laser Doppler anemometry. Neuroradiology 2010; 53:267-72. [PMID: 20563572 DOI: 10.1007/s00234-010-0723-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2009] [Accepted: 05/17/2010] [Indexed: 11/25/2022]
Abstract
INTRODUCTION Hemodynamic modification by means of flow diversion is increasingly used for treatment of intracranial aneurysms. Despite of promising results, there is still a paucity of methods to reliably predict long-term success of this technique. Laser Doppler anemometry (LDA) can be used to quantify the influence of stents on intra-aneurysmal flow in vitro. METHODS All experiments were performed with a pulsatile model of a sidewall aneurysm. A physiologic flow was created with a circulatory experimental setup, and a transparent non-Newtonian glycerol-water solution was used to substitute human blood. Flow velocity was measured with a one-component LDA system, recording flow components parallel and perpendicular to the parent vessel. Three different stents (Solitaire, Silk, Phenox flow diverter) were deployed over the aneurysm neck, respectively. RESULTS Flow reduction was 67.59% (inflow zone), 9.65% (dome) and 37.94% (outflow zone) by the Solitaire stent. The Silk stent reduced the flow by 58.15% (inflow zone), 89.06% (dome) and 90.06% (outflow zone). The Phenox flow diverter reduced the flow by 96.76% (inflow zone), 90% (dome) and 90.91% (outflow zone) when positioned with narrow stent struts but increased the velocity of up to seven times compared to the unstented model when placed with loose strut packing in the proximal part of the aneurysm. CONCLUSION LDA is a feasible method to quantify intra-aneurysmal flow and flow reduction efficacy of stents in vitro. Flow reduction was negligible with a standard self-expanding stent. For dedicated flow diverters, it depended both on stent design and on appropriate positioning.
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Affiliation(s)
- Franziska Dorn
- Department of Neuroradiology, Klinikum rechts der Isar, Technische Universitaet Muenchen, Munich, Germany.
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Turowski B, Macht S, Kulcsár Z, Hänggi D, Stummer W. Early fatal hemorrhage after endovascular cerebral aneurysm treatment with a flow diverter (SILK-Stent): do we need to rethink our concepts? Neuroradiology 2010; 53:37-41. [PMID: 20339842 DOI: 10.1007/s00234-010-0676-7] [Citation(s) in RCA: 187] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2009] [Accepted: 02/26/2010] [Indexed: 11/28/2022]
Abstract
A 69-year-old woman presenting with short lasting recent episodes of visual impairment was treated uneventfully with a flow diverter covering the neck of a large paraophthalmic aneurysm. As angiography showed immediate flow reduction we abstained from additional coiling which was initially planned. Eleven days later CT demonstrated nearly complete thrombosis of the aneurysm. Twenty days after treatment the patient suffered a lethal subarachnoid hemorrhage after rupture of the aneurysm. All available data were reviewed and beside hemodynamic factors instability of the intra-aneurysmal thrombus is discussed as a possible cofactor leading to this disastrous event.
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Affiliation(s)
- Bernd Turowski
- Institute of Radiology/Neuroradiology, University of Duesseldorf, Duesseldorf, Germany.
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Lozen A, Manjila S, Rhiew R, Fessler R. Y-stent-assisted coil embolization for the management of unruptured cerebral aneurysms: report of six cases. Acta Neurochir (Wien) 2009; 151:1663-72. [PMID: 19618104 DOI: 10.1007/s00701-009-0436-9] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2009] [Accepted: 05/22/2009] [Indexed: 10/20/2022]
Abstract
BACKGROUND The advent of stent-assisted coil embolization has revolutionized the endovascular management of complex intracranial aneurysms. Although performed routinely in most cerebrovascular centers, there are not many case series reported about the Y-stent technique for coil placement in cerebral aneurysms. The authors present the second largest series available within the neurosurgical literature. METHODS The authors have retrospectively reviewed the medical records and angiographic data of six patients who were diagnosed as having unruptured cerebral aneurysms and subsequently treated using "Y" stent-assisted coil embolization. Five out of six cerebral aneurysms in this study were located at the basilar tip while the remaining one was at the left MCA trifurcation. Aneurysms ranged in size from 8-22 mm. All patients were female with ages ranging from 37-70 years. One patient presented with recurrence of an aneurysm previously managed with a balloon-assisted coil embolization. Another patient presented after a failed trial of a balloon-assisted procedure. One patient had originally been diagnosed with multiple aneurysms of varying size and location. RESULTS A "Y" configuration was successfully established in all six patients. Five patients have had a symptom-free recovery period at average follow-up period of 36.7 months. The remaining patient is notable for recurrence that was discovered on angiogram 32 months postoperatively. CONCLUSIONS The proposed Y-stent technique is a safe and effective option that can be employed in the endovascular reconstruction of unruptured intracranial aneurysms of complex location and orientation. These methods serve as an acceptable alternative in the management of aneurysms traditionally managed with microsurgery. Hemodynamic assessment has shown Y-stenting to be an advantageous therapy option, yet further studies are required to assess these parameters in alternative therapies.
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Kühn AL, Roth C, Romeike B, Grunwald IQ. Treatment of elastase-induced intracranial aneurysms in New Zealand white rabbits by use of a novel neurovascular embolization stent device. Neuroradiology 2009; 56:59-65. [DOI: 10.1007/s00234-009-0605-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2009] [Accepted: 09/25/2009] [Indexed: 11/24/2022]
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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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Sadasivan C, Cesar L, Seong J, Wakhloo AK, Lieber BB. Treatment of rabbit elastase-induced aneurysm models by flow diverters: development of quantifiable indexes of device performance using digital subtraction angiography. IEEE TRANSACTIONS ON MEDICAL IMAGING 2009; 28:1117-1125. [PMID: 19164085 PMCID: PMC2702458 DOI: 10.1109/tmi.2008.2012162] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
It has been known for more than a decade that intracranial aneurysms can be successfully treated by deploying a porous meshed tube in the parent vessel of the aneurysm. Such devices are currently called flow diverters because they promote intraneurysmal flow stasis and thrombosis by diverting blood flow away from the aneurysm sac. The objective of this study was to use angiographic data to quantify and compare the performance of flow diverters of original design in successfully occluding an experimental aneurysm model. Three different configurations of a novel flow diverter with varying porosities and pore densities were implanted in 30 rabbit elastase-induced aneurysms. Temporal variations in angiographic contrast intensity within the aneurysms were fit to a mathematical model. Optimized model parameters were supplemented by the angiographic percentage aneurysm occlusion and an angiographic measure of device flexibility to derive composite scores of performance. Angiographic quantification further suggested a parameter, which could be employed to estimate long-term aneurysm occlusion probabilities immediately after treatment. Performance scores showed that the device with a porosity of 70% and pore density of 18 pores/mm (2) performed better than devices with 65% porosity, 14 pores/mm (2), and 70% porosity, 12 pores/mm (2) with relative efficacies of 100%, 84%, and 76%, respectively. The pore density of flow diverters, rather than porosity, may thus be a critical factor modulating device efficacy. A value of the prognostic parameter of less than 30 predicted greater than 97% angiographic aneurysm occlusion over six months with a sensitivity of 73% and specificity of 82%.
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Affiliation(s)
- Chander Sadasivan
- Department of Biomedical Engineering, Universityof Miami, Coral Gables, FL 33146, USA.
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Carotid artery stenting using a novel self-expanding braided nickel-titanium stent: feasibility and safety porcine trial. Cardiovasc Intervent Radiol 2009; 32:1019-27. [PMID: 19533229 PMCID: PMC2744778 DOI: 10.1007/s00270-009-9572-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/27/2008] [Revised: 03/12/2009] [Accepted: 03/16/2009] [Indexed: 02/01/2023]
Abstract
We studied the deliverability and safety of a braided, self-expanding, closed-cell nickel–titanium (NiTi) stent (E-volution, Jotec GmbH, Hechingen, Germany) especially designed for the endovascular treatment of carotid artery bifurcation stenosis with special regard to in-stent stenosis and thrombosis compared with a laser-cut reference nitinol stent in a porcine model of percutaneous vascular interventions. We aimed to assess histopathologic response in minipig carotid and subclavian arteries. Eight minipigs received a total of 42 stents: 14 reference stents and 28 E-volution stents. Eleven of the E-volution stents were additionally coated with heparin. Control angiography was obtained immediately before and after vascular intervention as well as 4 weeks after the procedure. Primary endpoints were 28 days of angiographic analyses as well as histomorphometric analysis, including injury score, inflammation score, luminal diameter, vessel diameter, maximal neointimal thickness, and area of in-stent stenosis. Secondary end points were procedural success, 28-day mortality, and stent thrombosis. All stents could be delivered successfully without procedural complications, morbidity, or mortality during our observation time. As confirmed by histology, no in-stent thrombosis was observed. Compared with common carotid arteries, subclavian arteries are significantly more vulnerable to developing in-stent stenosis caused by neointima proliferation (p < 0.05). Compared with the use of 1 single stent/artery, serial application of two stents leads to a more excessive but not significantly different neointimal proliferation (p > 0.05). The E-volution stent, especially when heparin coated, is in line with the comparison to the laser-cut reference stent displaying similar results of angiographic, histologic, and histomorphometric analyses (p > 0.05). Compared with the reference laser-cut stent, the self-expanding nitinol stent (E-volution) with its advanced braiding technology is feasible and safe. In our opinion, the high radial resistive force and the advanced braided design with tight stent-strut interstices may be beneficial in terms of plaque stabilization. Further studies are necessary and warranted.
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Kallmes DF, Ding YH, Dai D, Kadirvel R, Lewis DA, Cloft HJ. A second-generation, endoluminal, flow-disrupting device for treatment of saccular aneurysms. AJNR Am J Neuroradiol 2009; 30:1153-8. [PMID: 19369609 DOI: 10.3174/ajnr.a1530] [Citation(s) in RCA: 160] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE We report a preclinical study of a second-generation endoluminal device (Pipeline Embolization Device [PED-2] for aneurysmal occlusion and compare the PED-2 with its first-generation predecessor (PED-1). MATERIALS AND METHODS Our Institutional Animal Care and Use Committee approved all studies. The PED-2 is a braided endoluminal, flow-diverting device and was implanted across the necks of 18 elastase-induced aneurysms in New Zealand white rabbits and followed for 1 month (n = 6), 3 months (n = 6), and 6 months (n = 6). A second PED-2 was implanted in the abdominal aorta to cover the origins of the lumbar arteries. Angiographic occlusion rates were documented as complete, near-complete, and incomplete. Parent artery percent diameter stenosis was calculated. Results were compared with a previous publication focused on the PED-1, with use of the same model. We compared ordinal outcomes using Fisher Exact or chi(2) tests. We compared continuous data using analysis of variance. RESULTS Occlusion rates (complete and incomplete) for the PED-2 were noted in 17 cases (94%) and 1 (6%), respectively, compared with 9 cases of complete (53%) and 8 (47%) of incomplete occlusion with the PED-1 (P = .0072). No incidents of branch artery occlusion or distal emboli in vessels downstream of the parent artery were observed with the PED-2. Parent artery neointimal hyperplasia was minimal in most cases and was significantly less than in the PED-1. CONCLUSIONS The PED-2 is a biocompatible and hemocompatible device that occludes saccular aneurysms while preserving the parent artery and small-branch vessels in our animal model.
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Affiliation(s)
- D F Kallmes
- Department of Radiology, Mayo Clinic, Rochester, MN 55905, USA.
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Sadasivan C, Cesar L, Seong J, Rakian A, Hao Q, Tio FO, Wakhloo AK, Lieber BB. An original flow diversion device for the treatment of intracranial aneurysms: evaluation in the rabbit elastase-induced model. Stroke 2009; 40:952-8. [PMID: 19150864 DOI: 10.1161/strokeaha.108.533760] [Citation(s) in RCA: 161] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND AND PURPOSE The potential for successful treatment of intracranial aneurysms by flow diversion is gradually being recognized in the clinical setting; however, the devices currently available (stents) are not designed for flow diversion. We evaluate the long-term response of an appropriately designed flow diversion device in producing thrombotic occlusion of experimental aneurysms. METHODS Three different configurations of an original flow diversion device were implanted across thirty elastase-induced aneurysm models in rabbits. Ten animals per device configuration were followed-up for 3 weeks (n=3), 3 months (n=3), or 6 months (n=4), and tissue explanted postsacrifice was sent for histology. The temporal variation in angiographic contrast intensity within each aneurysm was fitted with a mathematical model to quantify the alteration in local hemodynamics caused by the implanted device. A predictive index, called the washout coefficient, was constructed to estimate long-term aneurysm occlusion probabilities immediately after treatment with any flow diversion device. RESULTS The device with a porosity of 70% and pore density of 18 pores/mm(2) performed better at occluding aneurysms than devices with 70% porosity, 12 pores/mm(2) and 65% porosity, 14 pores/mm(2). A value of the washout coefficient less than 30 predicted greater than 97% angiographic aneurysm occlusion over a period of 6 months with a sensitivity of 73% and specificity of 82%. CONCLUSIONS The flow diversion devices effected successful and stable aneurysm occlusion. Pore density, rather than porosity, may be the critical factor modulating efficacy of such devices.
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Affiliation(s)
- Chander Sadasivan
- Department of Biomedical Engineering, University of Miami, Coral Gables, FL, USA
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Lubicz B, Collignon L, Lefranc F, Bruneau M, Brotchi J, Balériaux D, De Witte O. Circumferential and fusiform intracranial aneurysms: reconstructive endovascular treatment with self-expandable stents. Neuroradiology 2008; 50:499-507. [PMID: 18365185 DOI: 10.1007/s00234-008-0366-x] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2007] [Accepted: 01/24/2008] [Indexed: 11/25/2022]
Abstract
INTRODUCTION We report our experience with endovascular treatment (EVT) of circumferential and fusiform intracranial aneurysms by a reconstructive approach with self-expandable stents. METHODS A retrospective review of our prospectively maintained database identified all circumferential and fusiform aneurysms treated by a reconstructive endovascular approach over a 3-year period. Clinical charts, procedural data, and angiographic results were reviewed. RESULTS From April 2004 to May 2007, 13 patients were identified, of whom 12 were asymptomatic and 1 presented with a subarachnoid hemorrhage. Two patients with an aneurysm <or=2 mm were treated by stent-within-stent placement without coiling (group 1). In 11 patients with a larger aneurysm, stenting with subsequent coiling was performed (group 2). In this latter approach, a balloon was temporarily inflated within the stent to ensure safe coil delivery. All patients showed an excellent clinical outcome. Asymptomatic procedural complications occurred in three patients, two with cervical internal carotid artery dissection and one with retroperitoneal hematoma. In patients of group 1, the aneurysm had completely disappeared at 6 months. In patients of group 2, aneurysm occlusion was complete in three and incomplete in eight. Follow-up angiography in 12 patients showed four with further thrombosis, six with stable results, and two with minor recanalization. CONCLUSION Circumferential and fusiform intracranial aneurysms may be treated by a reconstructive endovascular approach with self-expandable stents. In small aneurysms, a stent-within-stent technique is effective, whereas stenting and subsequent coiling is indicated in larger aneurysms. This therapeutic protocol is associated with good clinical and anatomical results.
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Affiliation(s)
- Boris Lubicz
- Department of Neuroradiology, Erasme University Hospital, Brussels, Belgium.
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