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Bérod A, Mut F, Cebral J, Mendez S, Chnafa C, Nicoud F. Assessing a heterogeneous model for accounting for endovascular devices in hemodynamic simulations of cerebral aneurysms. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2023; 39:e3762. [PMID: 37515447 DOI: 10.1002/cnm.3762] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 12/18/2022] [Accepted: 07/12/2023] [Indexed: 07/30/2023]
Abstract
The heterogeneous model developed by Berod et al [Int J Numer Method Biomed Eng 38, 2021] for representing the hemodynamic effects of endovascular prostheses is applied to a series of 10 patient specific cerebral aneurysms, 6 being treated by flow diverters, 4 being equipped with WEBs. Two markers correlated with the medical outcome of the treatment are used to assess the potential of the model, namely the saccular mean velocity and the inflow rate at the neck of the aneurysm. The comparison with the corresponding wire-resolved simulations is very favorable in both cases, and the model-based simulations also retrieve the jetting-type flows generated downstream of the struts. Noteworthy, the very same model was used for representing the flow diverters and the WEBs, showing the versatility and robustness of the heterogeneous modeling of the devices.
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Affiliation(s)
| | - Fernando Mut
- Bioengineering Department, Volgenau School of Engineering, George Mason University, Fairfax, Virginia, USA
| | - Juan Cebral
- Bioengineering Department, Volgenau School of Engineering, George Mason University, Fairfax, Virginia, USA
| | - Simon Mendez
- CNRS, IMAG, Université de Montpellier, Montpellier, France
| | | | - Franck Nicoud
- CNRS, IMAG, Université de Montpellier, Montpellier, France
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Pravdivtseva MS, Pravdivtsev AN, Peters S, Hensler J, Larsen N, Hövener JB, Jansen O, Wodarg F. The effect of the size of the new contour neurovascular device for altering intraaneurysmal flow. Interv Neuroradiol 2023:15910199221145985. [PMID: 36594503 DOI: 10.1177/15910199221145985] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND Recently, a novel intrasaccular device (contour neurovascular system, contour) was introduced to treat intracranial aneurysms. Contour is placed at thе aneurysm neck and reduces the intraaneurysmal blood inflow. Contour comes in a range of sizes to target different aneurysms. The efficiency of altering flow with contour and the effect of device size have not yet been investigated. Therefore, we studied the effect of the device size with patient-based aneurysm models using 2D digital subtraction angiography (DSA). METHODS Three patient-based aneurysm models with necks ranging from 2.7 to 9.7 mm were produced, providing standardized testing conditions. Contours with diameters of 5, 11, and 14 mm were implanted into the models, four of each size. 2D DSA images were acquired before and after implanting contour (15 frames/s, manual contrast injection). After injecting angiographic contrast agent, the DSA signal was recorded over time to calculate the contrast washout time (WOT), which is a measure of flow diversion efficiency. RESULTS All contour devices caused contrast agent stasis and increased WOT in aneurysm sac (p-value = 0.0005). The median relative WOT was largest for 5-mm contour (6.6 ± 3.2) and similar for 11-mm contour (3.4 ± 2.6) and 14-mm contour (3.2 ± 3.8). The implantation procedure might affect WOT values even for contours of the same size; the overall relative WOT ranged between 1.5 and 10.89. CONCLUSION The 5-mm contour showed the longest WOT value in our study, while no apparent difference between 11-mm contour and 14-mm contour was found.
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Affiliation(s)
- Mariya S Pravdivtseva
- Department of Radiology and Neuroradiology, Section Biomedical Imaging, Molecular Imaging North Competence Center (MOIN CC), 54186University Medical Center Schleswig-Holstein (UKSH), Kiel University, Kiel, Germany
| | - Andrey N Pravdivtsev
- Department of Radiology and Neuroradiology, Section Biomedical Imaging, Molecular Imaging North Competence Center (MOIN CC), 54186University Medical Center Schleswig-Holstein (UKSH), Kiel University, Kiel, Germany
| | - Sönke Peters
- Department of Radiology and Neuroradiology, 9179University Medical Center Schleswig-Holstein (UKSH), Kiel, Germany
| | - Johannes Hensler
- Department of Radiology and Neuroradiology, 9179University Medical Center Schleswig-Holstein (UKSH), Kiel, Germany
| | - Naomi Larsen
- Department of Radiology and Neuroradiology, 9179University Medical Center Schleswig-Holstein (UKSH), Kiel, Germany
| | - Jan-Bernd Hövener
- Department of Radiology and Neuroradiology, Section Biomedical Imaging, Molecular Imaging North Competence Center (MOIN CC), 54186University Medical Center Schleswig-Holstein (UKSH), Kiel University, Kiel, Germany
| | - Olav Jansen
- Department of Radiology and Neuroradiology, 9179University Medical Center Schleswig-Holstein (UKSH), Kiel, Germany
| | - Fritz Wodarg
- Department of Radiology and Neuroradiology, 9179University Medical Center Schleswig-Holstein (UKSH), Kiel, Germany
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Tikhvinskii D, Kuianova J, Kislitsin D, Orlov K, Gorbatykh A, Parshin D. Numerical Assessment of the Risk of Abnormal Endothelialization for Diverter Devices: Clinical Data Driven Numerical Study. J Pers Med 2022; 12:jpm12040652. [PMID: 35455768 PMCID: PMC9025183 DOI: 10.3390/jpm12040652] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 04/07/2022] [Accepted: 04/08/2022] [Indexed: 12/07/2022] Open
Abstract
Numerical modeling is an effective tool for preoperative planning. The present work is devoted to a retrospective analysis of neurosurgical treatments for the occlusion of cerebral aneurysms using flow-diverters and hemodynamic factors affecting stent endothelization. Several different geometric approaches have been considered for virtual flow-diverters deployment. A comparative analysis of hemodynamic parameters as a result of computational modeling has been carried out basing on the four clinical cases: one successful treatment, one with no occlusion and two with in stent stenosis. For the first time, a quantitative assessment of both: the limiting magnitude of shear stresses that are necessary for the occurrence of in stent stenosis (MaxWSS > 1.23) and for conditions in which endothelialization is insufficiently active and occlusion of the cervical part of the aneurysm does not occur (MaxWSS < 1.68)—has been statistacally proven (p < 0.01).
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Affiliation(s)
- Denis Tikhvinskii
- Lavrentyev Institute of Hydrodynamics SB RAS, Lavrentiev Avenue 15, 630090 Novosibirsk, Russia; (D.T.); (J.K.)
| | - Julia Kuianova
- Lavrentyev Institute of Hydrodynamics SB RAS, Lavrentiev Avenue 15, 630090 Novosibirsk, Russia; (D.T.); (J.K.)
| | - Dmitrii Kislitsin
- Neurosurgery Department, Meshalkin National Medical Research Center, 630055 Novosibirsk, Russia; (D.K.); (K.O.); (A.G.)
| | - Kirill Orlov
- Neurosurgery Department, Meshalkin National Medical Research Center, 630055 Novosibirsk, Russia; (D.K.); (K.O.); (A.G.)
| | - Anton Gorbatykh
- Neurosurgery Department, Meshalkin National Medical Research Center, 630055 Novosibirsk, Russia; (D.K.); (K.O.); (A.G.)
| | - Daniil Parshin
- Lavrentyev Institute of Hydrodynamics SB RAS, Lavrentiev Avenue 15, 630090 Novosibirsk, Russia; (D.T.); (J.K.)
- Correspondence: ; Tel.: +7-383-333-16-12
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Roloff C, Berg P. Effect of flow diverter stent malposition on intracranial aneurysm hemodynamics—An experimental framework using stereoscopic particle image velocimetry. PLoS One 2022; 17:e0264688. [PMID: 35235597 PMCID: PMC8890739 DOI: 10.1371/journal.pone.0264688] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Accepted: 02/15/2022] [Indexed: 12/04/2022] Open
Abstract
Background Flow-diverting stents are increasingly used for the minimally-invasive treatment of intracranial aneurysms. However, a correct positioning of such devices can be challenging due to varying vessel diameters as well as the complex anatomy of the neurovasculature. As a consequence, unsuccessful treatment outcomes are increasingly reported requiring an improvement of the understanding of stent-induced flow modification. Methods To evaluate the effect of different degrees of flow diverter stent malposition on intra-aneurysmal hemodynamic changes, a controlled hemodynamic configuration was created using an idealized intracranial aneurysms model. Afterwards, four different treatment scenarios were reproduced comprising of 1) the ideal treatment, 2) an insufficient wall apposition in the region of the ostium, 3) a distorted device migrating into the aneurysm sac and 4) an inaccurately deployed stent due to wrong release location. For the assessment of the individual flow modifications, high-resolution stereoscopic particle image velocimetry (PIV) measurements were carried out. Results The analysis of the precise in-vitro PIV measurements reveals that in all cases a considerable reduction of the cycle-averaged and peak-systolic velocity was obtained. Compared to the untreated aneurysm configuration, the flow reduction ranged from 63% (scenario 4) up to 89% (scenario 3). The ideal treatment reached a reduction of 78%, which is known to be sufficient for a successful therapy. However, inaccurate device positioning leads to increased oscillating flow towards the lateral directions reducing the chances of sufficient thrombus formation. Conclusions High-resolution in-vitro PIV measurements enable an accurate quantification of the treatment efficacy for flow-diverting devices. Furthermore, insufficient treatment outcomes can be reproduces allowing for an assessment of intra-aneurysmal hemodynamic changes.
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Affiliation(s)
- Christoph Roloff
- Laboratory of Fluid Dynamics and Technical Flows, University of Magdeburg, Magdeburg, Germany
| | - Philipp Berg
- Laboratory of Fluid Dynamics and Technical Flows, University of Magdeburg, Magdeburg, Germany
- Research Campus STIMULATE, University of Magdeburg, Magdeburg, Germany
- * E-mail:
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Berod A, Chnafa C, Mendez S, Nicoud F. A heterogeneous model of endovascular devices for the treatment of intracranial aneurysms. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2022; 38:e3552. [PMID: 34806847 DOI: 10.1002/cnm.3552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 03/25/2021] [Accepted: 07/31/2021] [Indexed: 06/13/2023]
Abstract
Numerical computations of hemodynamics inside intracranial aneurysms treated by endovascular braided devices such as flow-diverters contribute to understanding and improving such treatment procedures. Nevertheless, these simulations yield high computational and meshing costs due to the heterogeneity of length scales between the dense weave of the fine struts of the device and the arterial volume. Homogeneous strategies developed over the last decade to circumvent this issue substitute local dissipations due to the wires with a global effect in the form of a pressure-drop across the device surface. However, these methods cannot accurately reproduce the flow-patterns encountered near the struts, the latter strongly dictating the intra-saccular flow environment. In this work, a versatile theoretical framework which aims at correctly reproducing the local flow heterogeneities due to the wires while keeping memory consumption, meshing and computational times as low as possible is introduced. This model reproduces the drag forces exerted by the device struts onto the fluid, thus producing local and heterogeneous effects on the flow. Extensive validation for various flow and geometric configurations using an idealized device is performed. To further illustrate the method capabilities, a real patient-specific aneurysm endovascularly treated with a flow-diverter is used, enabling quantitative comparisons with classical approaches for both intra-saccular velocities and computational costs reduction. The proposed heterogeneous model endeavors to bridge the gap between computational fluid dynamics and clinical applications and ushers in a new era of numerical treatment planning with minimally costing computational tools.
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Affiliation(s)
- Alain Berod
- IMAG, Univ Montpellier, CNRS, Montpellier, France
- Sim&Cure, Montpellier, France
| | | | - Simon Mendez
- IMAG, Univ Montpellier, CNRS, Montpellier, France
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Winters H, Schüngel MS, Scherlach C, Mucha D, Thalwitzer J, Härtig W, Donitza A, Bailis N, Maybaum J, Hoffmann KT, Quäschling U, Schob S. First Experience of Three Neurovascular Centers With the p64MW-HPC, a Low-Profile Flow Diverter Designed for Proximal Cerebral Vessels With Antithrombotic Coating. Front Neurol 2021; 12:724705. [PMID: 34594297 PMCID: PMC8476967 DOI: 10.3389/fneur.2021.724705] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Accepted: 08/12/2021] [Indexed: 12/23/2022] Open
Abstract
Background: In the last decade, flow diversion (FD) has been established as hemodynamic treatment for cerebral aneurysms arising from proximal and distal cerebral arteries. However, two significant limitations remain—the need for 0.027” microcatheters required for delivery of most flow diverting stents (FDS), and long-term dual anti-platelet therapy (DAPT) in order to prevent FDS-associated thromboembolism, at the cost of increasing the risk for hemorrhage. This study reports the experience of three neurovascular centers with the p64MW-HPC, a FDS with anti-thrombotic coating that is implantable via a 0.021” microcatheter. Materials and methods: Three neurovascular centers contributed to this retrospective analysis of patients that had been treated with the p64MW-HPC between March 2020 and March 2021. Clinical data, aneurysm characteristics, and follow-up results, including procedural and post-procedural complications, were recorded. The hemodynamic effect was assessed using the O'Kelly–Marotta Scale (OKM). Results: Thirty-two patients (22 female, mean age 57.1 years) with 33 aneurysms (27 anterior circulation and six posterior circulation) were successfully treated with the p64MW-HPC. In 30/32 patients (93.75%), aneurysmal perfusion was significantly reduced immediately post implantation. Follow-up imaging was available for 23 aneurysms. Delayed aneurysm perfusion (OKM A3: 8.7%), reduction in aneurysm size (OKM B1-3: 26.1%), or sufficient separation from the parent vessel (OKM C1-3 and D1: 65.2%) was demonstrated at the last available follow-up after a mean of 5.9 months. In two cases, device thrombosis after early discontinuation of DAPT occurred. One delayed rupture caused a caroticocavernous fistula. The complications were treated sufficiently and all patients recovered without permanent significant morbidity. Conclusion: Treatment with the p64MW-HPC is safe and feasible and achieves good early aneurysm occlusion rates in the proximal intracranial circulation, which are comparable to those of well-established FDS. Sudden interruption of DAPT in the early post-interventional phase can cause in-stent thrombosis despite the HPC surface modification. Deliverability via the 0.021” microcatheter facilitates treatment in challenging vascular anatomies.
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Affiliation(s)
- Helge Winters
- Institut für Neuroradiologie, Universitätsklinikum Leipzig, Leipzig, Germany.,Klinik und Poliklinik für Anästhesiologie und Intensivtherapie, Universitätsklinikum Leipzig, Leipzig, Germany
| | | | - Cordula Scherlach
- Institut für Neuroradiologie, Universitätsklinikum Leipzig, Leipzig, Germany
| | - Dirk Mucha
- Institut für Radiologie und Neuroradiologie, Heinrich-Braun- Klinikum, Zwickau, Germany
| | - Jörg Thalwitzer
- Institut für Radiologie und Neuroradiologie, Klinikum Chemnitz gGmbH, Chemnitz, Germany
| | - Wolfgang Härtig
- Paul-Flechsig-Institut für Hirnforschung, Universität Leipzig, Leipzig, Germany
| | - Aneta Donitza
- Abteilung für Neuroradiologie, Klinik & Poliklinik für Radiologie, Universitätsklinikum Halle, Halle (Saale), Germany
| | - Nikolaos Bailis
- Institut für Neuroradiologie, Universitätsklinikum Leipzig, Leipzig, Germany
| | - Jens Maybaum
- Institut für Neuroradiologie, Universitätsklinikum Leipzig, Leipzig, Germany
| | - Karl Titus Hoffmann
- Institut für Neuroradiologie, Universitätsklinikum Leipzig, Leipzig, Germany
| | - Ulf Quäschling
- Institut für Neuroradiologie, Universitätsklinikum Leipzig, Leipzig, Germany
| | - Stefan Schob
- Abteilung für Neuroradiologie, Klinik & Poliklinik für Radiologie, Universitätsklinikum Halle, Halle (Saale), Germany
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