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Jun YJ, Hwang DK, Lee HS, Kim BM, Park KD. Flow Diverter Performance Comparison of Different Wire Materials for Effective Intracranial Aneurysm Treatment. Bioengineering (Basel) 2024; 11:76. [PMID: 38247953 PMCID: PMC10813681 DOI: 10.3390/bioengineering11010076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 01/05/2024] [Accepted: 01/09/2024] [Indexed: 01/23/2024] Open
Abstract
A flow diverter (FD) is an effective method for treating wide-necked intracranial aneurysms by inducing hemodynamic changes in aneurysms. However, the procedural technique remains challenging, and it is often not performed properly in many cases of deployment or placements. In this study, three types of FDs that changed the material of the wire were prepared within the same structure. Differences in physical properties, such as before and after delivery loading stent size, radial force, and radiopacity, were evaluated. The performances in terms of deployment and trackability force were also evaluated in a simulated model using these FDs. Furthermore, changes of deployment patterns when these FDs were applied to a 3D-printed aneurysm model were determined. The NiTi FD using only nitinol (NiTi) wire showed 100% size recovery and 42% to 45% metal coverage after loading. The low trackability force (10.9 to 22.9 gf) allows smooth movement within the delivery system. However, NiTi FD cannot be used in actual surgeries due to difficulties in X-ray identification. NiTi-Pt/W FD, a combination of NiTi wire and platinum/tungsten (Pt/W) wire, had the highest radiopacity and compression force (6.03 ± 0.29 gf) among the three FDs. However, it suffered from high trackability force (22.4 to 39.9 gf) and the end part braiding mesh tended to loosen easily, so the procedure became more challenging. The NiTi(Pt) FD using a platinum core nitinol (NiTi(Pt)) wire had similar trackability force (11.3 to 22.1 gf) to NiTi FD and uniform deployment, enhancing procedural convenience. However, concerns about low expansion force (1.79 ± 0.30 gf) and the potential for migration remained. This comparative analysis contributes to a comprehensive understanding of how different wire materials influence the performance of FDs. While this study is still in its early stages and requires further research, its development has the potential to guide clinicians and researchers in optimizing the selection and development of FDs for the effective treatment of intracranial aneurysms.
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Affiliation(s)
- Yeo Jin Jun
- Taewoong Medical, 14, Gojeong-ro, Wolgot-myeon, Gimpo-si 10022, Republic of Korea; (Y.J.J.); (D.K.H.); (H.S.L.)
- Department of Molecular Science and Technology, Ajou University, 206, World Cup-ro, Yeongtong-gu, Suwon-si 16499, Republic of Korea
| | - Doo Kyung Hwang
- Taewoong Medical, 14, Gojeong-ro, Wolgot-myeon, Gimpo-si 10022, Republic of Korea; (Y.J.J.); (D.K.H.); (H.S.L.)
| | - Hee Sun Lee
- Taewoong Medical, 14, Gojeong-ro, Wolgot-myeon, Gimpo-si 10022, Republic of Korea; (Y.J.J.); (D.K.H.); (H.S.L.)
| | - Byung Moon Kim
- Department of Radiology, Severance Stroke Center, Severance Hospital, Yonsei University College of Medicine, 50-1, Yonsei-ro, Seodaemun-gu, Seoul 03722, Republic of Korea;
| | - Ki Dong Park
- Department of Molecular Science and Technology, Ajou University, 206, World Cup-ro, Yeongtong-gu, Suwon-si 16499, Republic of Korea
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Velvaluri P, Pravdivtseva MS, Hensler J, Wodarg F, Jansen O, Quandt E, Hövener JB. A realistic way to investigate the design, and mechanical properties of flow diverter stents. Expert Rev Med Devices 2021; 18:569-579. [PMID: 33890849 DOI: 10.1080/17434440.2021.1920923] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
PURPOSE Braided flow diverters (FD) are highly sophisticated, delicate, and intricate mechanical devices used to treat intracranial aneurysms. Testing such devices in vitro, however, remains an unsolved challenge. Here, we evaluate methods to measure flow, design and mechanical properties in vitro. METHODS Flow properties, cell porosity, pore density, and cell area were evaluated under geometrically realistic conditions by placing FDs in patient-derived, 3D-printed models of human vasculature. 4D flow MRI was used to measure fluid dynamics. Laser microscopy was used to measure the design properties of the FDs. New methods were developed to investigate the bending, circumferential, and longitudinal radial force of the FDs continuously over varying diameters. RESULTS The placement and flow properties of the FD in the vasculature models were successfully measured by MRI, although artifacts occurred. Likewise, the porosity, pore density, and cell area were successfully measured inside of the models using a laser microscope. The newly developed mechanical methods allowed to measure the indicated forces - to our knowledge for the first time - continuously. CONCLUSION Modern and specifically tailored techniques, some of which were presented here for the first time, allow detailed insights into the flow, design, and mechanical properties of braided flow diverter stents.
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Affiliation(s)
| | - Mariya S Pravdivtseva
- Section Biomedical Imaging, Molecular Imaging North Competence Center (MOIN CC), Department of Radiology and Neuroradiology, University Medical Center Schleswig-Holstein (UKSH), Kiel University, Kiel, Germany
| | - Johannes Hensler
- Department of Radiology and Neuroradiology, University Medical Center Schleswig-Holstein (UKSH), Kiel University, Kiel, Germany
| | - Fritz Wodarg
- Department of Radiology and Neuroradiology, University Medical Center Schleswig-Holstein (UKSH), Kiel University, Kiel, Germany
| | - Olav Jansen
- Department of Radiology and Neuroradiology, University Medical Center Schleswig-Holstein (UKSH), Kiel University, Kiel, Germany
| | - Eckhard Quandt
- Chair of Inorganic Functional Materials, Kiel University, Kiel, Germany
| | - Jan-Bernd Hövener
- Section Biomedical Imaging, Molecular Imaging North Competence Center (MOIN CC), Department of Radiology and Neuroradiology, University Medical Center Schleswig-Holstein (UKSH), Kiel University, Kiel, Germany
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Paliwal N, Tutino VM, Shallwani H, Beecher JS, Damiano RJ, Shakir HJ, Atwal GS, Fennell VS, Natarajan SK, Levy EI, Siddiqui AH, Davies JM, Meng H. Ostium Ratio and Neck Ratio Could Predict the Outcome of Sidewall Intracranial Aneurysms Treated with Flow Diverters. AJNR Am J Neuroradiol 2019; 40:288-294. [PMID: 30679216 DOI: 10.3174/ajnr.a5953] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Accepted: 11/07/2018] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Incompletely occluded flow diverter treated aneurysms remain at risk of rupture and thromboembolic complications. Our aim was to identify the potential for incomplete occlusion of intracranial aneurysms treated by flow diverters. We investigated whether aneurysm ostium size in relation to parent artery size affects angiographic outcomes of flow diverter-treated sidewall aneurysms. MATERIALS AND METHODS Flow diverter-treated sidewall aneurysms were divided into "occluded" and "residual" (incomplete occlusion) groups based on 6-month angiographic follow-up. We calculated the ostium ratio, a new parameter defined as the aneurysm ostium surface area versus the circumferential surface area of the parent artery. We also calculated the neck ratio, defined as clinical aneurysm neck diameter versus parent artery diameter from pretreatment 2D DSA, as a 2D surrogate. We compared the performance of these ratios with existing aneurysm morphometrics (size, neck diameter, volume, aspect ratio, size ratio, undulation index, nonsphericity index, ellipticity index, bottleneck factor, aneurysm angle, and parent vessel angle) and flow diverter-related parameters (metal coverage rate and pore density). Statistical tests and receiver operating characteristic analyses were performed to identify significantly different parameters between the 2 groups and test their predictive performances. RESULTS We included 63 flow diverter-treated aneurysms, 46 occluded and 17 residual. The ostium ratio and neck ratio were significantly higher in the residual group than in the occluded group (P < .001 and P = .02, respectively), whereas all other parameters showed no statistical difference. As discriminating parameters for occlusion, ostium ratio and neck ratio achieved areas under the curve of 0.912 (95% CI, 0.838-0.985) and 0.707 (95% CI, 0.558-0.856), respectively. CONCLUSIONS High ostium ratios and neck ratios could predict incomplete occlusion of flow diverter-treated sidewall aneurysms. Neck ratio can be easily calculated by interventionists to predict flow-diverter treatment outcomes.
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Affiliation(s)
- N Paliwal
- From the Department of Mechanical and Aerospace Engineering (N.P., R.J.D., H.M.).,Canon Stroke and Vascular Research Center (N.P., V.M.T., R.J.D., E.I.L., A.H.S., J.M.D., H.M.)
| | - V M Tutino
- Canon Stroke and Vascular Research Center (N.P., V.M.T., R.J.D., E.I.L., A.H.S., J.M.D., H.M.).,Department of Biomedical Engineering (V.M.T., H.M.), University at Buffalo, Buffalo, New York.,Departments of Neurosurgery (V.M.T., H.S., J.S.B., H.J.S., G.S.A., V.S.F., S.K.N., E.I.L., A.H.S., J.M.D., H.M.)
| | - H Shallwani
- Departments of Neurosurgery (V.M.T., H.S., J.S.B., H.J.S., G.S.A., V.S.F., S.K.N., E.I.L., A.H.S., J.M.D., H.M.).,Department of Neurosurgery (H.S., J.S.B., H.J.S., G.S.A., V.S.F., S.K.N., A.H.S., J.M.D.), Gates Vascular Institute at Kaleida Health, Buffalo, New York
| | - J S Beecher
- Departments of Neurosurgery (V.M.T., H.S., J.S.B., H.J.S., G.S.A., V.S.F., S.K.N., E.I.L., A.H.S., J.M.D., H.M.).,Department of Neurosurgery (H.S., J.S.B., H.J.S., G.S.A., V.S.F., S.K.N., A.H.S., J.M.D.), Gates Vascular Institute at Kaleida Health, Buffalo, New York
| | - R J Damiano
- From the Department of Mechanical and Aerospace Engineering (N.P., R.J.D., H.M.).,Canon Stroke and Vascular Research Center (N.P., V.M.T., R.J.D., E.I.L., A.H.S., J.M.D., H.M.)
| | - H J Shakir
- Departments of Neurosurgery (V.M.T., H.S., J.S.B., H.J.S., G.S.A., V.S.F., S.K.N., E.I.L., A.H.S., J.M.D., H.M.).,Department of Neurosurgery (H.S., J.S.B., H.J.S., G.S.A., V.S.F., S.K.N., A.H.S., J.M.D.), Gates Vascular Institute at Kaleida Health, Buffalo, New York
| | - G S Atwal
- Departments of Neurosurgery (V.M.T., H.S., J.S.B., H.J.S., G.S.A., V.S.F., S.K.N., E.I.L., A.H.S., J.M.D., H.M.).,Department of Neurosurgery (H.S., J.S.B., H.J.S., G.S.A., V.S.F., S.K.N., A.H.S., J.M.D.), Gates Vascular Institute at Kaleida Health, Buffalo, New York
| | - V S Fennell
- Departments of Neurosurgery (V.M.T., H.S., J.S.B., H.J.S., G.S.A., V.S.F., S.K.N., E.I.L., A.H.S., J.M.D., H.M.).,Department of Neurosurgery (H.S., J.S.B., H.J.S., G.S.A., V.S.F., S.K.N., A.H.S., J.M.D.), Gates Vascular Institute at Kaleida Health, Buffalo, New York
| | - S K Natarajan
- Departments of Neurosurgery (V.M.T., H.S., J.S.B., H.J.S., G.S.A., V.S.F., S.K.N., E.I.L., A.H.S., J.M.D., H.M.).,Department of Neurosurgery (H.S., J.S.B., H.J.S., G.S.A., V.S.F., S.K.N., A.H.S., J.M.D.), Gates Vascular Institute at Kaleida Health, Buffalo, New York
| | - E I Levy
- Canon Stroke and Vascular Research Center (N.P., V.M.T., R.J.D., E.I.L., A.H.S., J.M.D., H.M.).,Departments of Neurosurgery (V.M.T., H.S., J.S.B., H.J.S., G.S.A., V.S.F., S.K.N., E.I.L., A.H.S., J.M.D., H.M.).,Radiology (E.I.L., A.H.S.)
| | - A H Siddiqui
- Canon Stroke and Vascular Research Center (N.P., V.M.T., R.J.D., E.I.L., A.H.S., J.M.D., H.M.).,Departments of Neurosurgery (V.M.T., H.S., J.S.B., H.J.S., G.S.A., V.S.F., S.K.N., E.I.L., A.H.S., J.M.D., H.M.).,Radiology (E.I.L., A.H.S.).,Department of Neurosurgery (H.S., J.S.B., H.J.S., G.S.A., V.S.F., S.K.N., A.H.S., J.M.D.), Gates Vascular Institute at Kaleida Health, Buffalo, New York.,Jacobs Institute (A.H.S., J.M.D.), Buffalo, New York
| | - J M Davies
- Canon Stroke and Vascular Research Center (N.P., V.M.T., R.J.D., E.I.L., A.H.S., J.M.D., H.M.).,Departments of Neurosurgery (V.M.T., H.S., J.S.B., H.J.S., G.S.A., V.S.F., S.K.N., E.I.L., A.H.S., J.M.D., H.M.).,Biomedical Informatics (J.M.D.), Jacobs School of Medicine, University at Buffalo, Buffalo, New York.,Department of Neurosurgery (H.S., J.S.B., H.J.S., G.S.A., V.S.F., S.K.N., A.H.S., J.M.D.), Gates Vascular Institute at Kaleida Health, Buffalo, New York.,Jacobs Institute (A.H.S., J.M.D.), Buffalo, New York
| | - H Meng
- From the Department of Mechanical and Aerospace Engineering (N.P., R.J.D., H.M.) .,Canon Stroke and Vascular Research Center (N.P., V.M.T., R.J.D., E.I.L., A.H.S., J.M.D., H.M.).,Department of Biomedical Engineering (V.M.T., H.M.), University at Buffalo, Buffalo, New York.,Departments of Neurosurgery (V.M.T., H.S., J.S.B., H.J.S., G.S.A., V.S.F., S.K.N., E.I.L., A.H.S., J.M.D., H.M.)
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Fahed R, Darsaut TE, Kotowski M, Salazkin I, Raymond J. Re-treatment of residual aneurysms after flow diversion: An experimental study. Neuroradiol J 2018. [PMID: 29513077 DOI: 10.1177/1971400918763198] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022] Open
Abstract
Aim Flow diverters are increasingly used to treat aneurysms, but treatment is not always effective. The management of aneurysms that fail to occlude following flow diversion is problematic. We aimed to reproduce failures in an animal model and study re-treatment with additional flow diverters alone or with flow diverters and liquid embolic agent. Material and methods Twenty wide-necked aneurysms were created at the carotid-lingual bifurcation in 10 dogs, and were treated with flow diverters 4-6 weeks later. Follow-up angiography was performed at three months. Suitable residual aneurysms were randomly allocated: re-treatment with flow diverters alone ( n = 6), or with the injection of liquid embolic between two layers of flow diverters ( n = 4) or no re-treatment ( n = 2). Angiography was repeated three months later, followed by euthanasia, photography and pathology. Results Patent wide-necked aneurysms were produced in 17/20 attempts (85%); three months after flow diversion there were 15/17 (88%) residual aneurysms. In three cases, re-treatment was not possible because the flow diverter had prolapsed into the aneurysm, leaving 12 aneurysms to study. Re-treated aneurysms showed improved angiographic results at six months (median score of 2; P = 0.03), but residual aneurysms were present in all cases. Parent artery occlusion occurred in two aneurysms treated with flow diverter plus liquid embolic. At pathology, aneurysms were only partially filled with thrombus; leaks through the flow diverters were found in the neointima connecting the arterial lumen to residual aneurysms. Conclusion Re-treatment of residual flow-diverted experimental aneurysms with additional flow diverters did not lead to aneurysm occlusion.
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Affiliation(s)
- Robert Fahed
- 1 Interventional Neuroradiology Research Laboratory, Centre Hospitalier de l'Université de Montréal (CHUM), Notre-Dame Hospital, Montreal, Canada.,2 Department of Interventional Neuroradiology, Rothschild Foundation Hospital, Paris, France
| | - Tim E Darsaut
- 3 Mackenzie Health Sciences Centre, University of Alberta Hospital, Edmonton, Canada
| | - Marc Kotowski
- 1 Interventional Neuroradiology Research Laboratory, Centre Hospitalier de l'Université de Montréal (CHUM), Notre-Dame Hospital, Montreal, Canada.,4 Department of Radiology, Centre Hospitalier de l'Université de Montréal (CHUM), Montreal, Canada
| | - Igor Salazkin
- 1 Interventional Neuroradiology Research Laboratory, Centre Hospitalier de l'Université de Montréal (CHUM), Notre-Dame Hospital, Montreal, Canada
| | - Jean Raymond
- 1 Interventional Neuroradiology Research Laboratory, Centre Hospitalier de l'Université de Montréal (CHUM), Notre-Dame Hospital, Montreal, Canada.,4 Department of Radiology, Centre Hospitalier de l'Université de Montréal (CHUM), Montreal, Canada
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