0
Research Papers

Hemodynamics of Flow Diverters

[+] Author and Article Information
Ronak Dholakia, Chander Sadasivan, David J. Fiorella, Henry H. Woo

Department of Neurological Surgery,
Stony Brook University Medical Center,
Stony Brook, NY 11794

Baruch B. Lieber

Professor
Department of Neurological Surgery,
Stony Brook University Medical Center,
HSC T12, Room 080,
100 Nicolls Road,
Stony Brook, NY 11794-8122
e-mail: Baruch.lieber@stonybrook.edu

1Corresponding author.

Apart from the device comparison section on Hemodynamics of Stents and Flow Diverters, portions of this paper appear as part of a book chapter in “Flow Diversion of Cerebral Aneurysms,” 2016, Min S. Park, Phil Taussky, Felipe C. Albuquerque, and Cameron G. McDougall, Eds., Thieme Medical Publishers, New York, www.thieme.com (Reprinted with Permission).Manuscript received June 29, 2016; final manuscript received September 21, 2016; published online January 19, 2017. Assoc. Editor: Victor H. Barocas.

J Biomech Eng 139(2), 021002 (Jan 19, 2017) (10 pages) Paper No: BIO-16-1270; doi: 10.1115/1.4034932 History: Received June 29, 2016; Revised September 21, 2016

Cerebral aneurysms are pathological focal evaginations of the arterial wall at and around the junctions of the circle of Willis. Their tenuous walls predispose aneurysms to leak or rupture leading to hemorrhagic strokes with high morbidity and mortality rates. The endovascular treatment of cerebral aneurysms currently includes the implantation of fine-mesh stents, called flow diverters, within the parent artery bearing the aneurysm. By mitigating flow velocities within the aneurysmal sac, the devices preferentially induce thrombus formation in the aneurysm within hours to days. In response to the foreign implant, an endothelialized arterial layer covers the luminal surface of the device over a period of days to months. Organization of the intraneurysmal thrombus leads to resorption and shrinkage of the aneurysm wall and contents, eventually leading to beneficial remodeling of the pathological site to a near-physiological state. The devices' primary function of reducing flow activity within aneurysms is corollary to their mesh structure. Complete specification of the device mesh structure, or alternately device permeability, necessarily involves the quantification of two variables commonly used to characterize porous media—mesh porosity and mesh pore density. We evaluated the flow alteration induced by five commercial neurovascular devices of varying porosity and pore density (stents: Neuroform, Enterprise, and LVIS; flow diverters: Pipeline and FRED) in an idealized sidewall aneurysm model. As can be expected in such a model, all devices substantially reduced intraneurysmal kinetic energy as compared to the nonstented case with the coarse-mesh stents inducing a 65–80% reduction whereas the fine-mesh flow diverters induced a near-complete flow stagnation (∼98% reduction). We also note a trend toward greater device efficacy (lower intraneurysmal flow) with decreasing device porosity and increasing device pore density. Several such flow studies have been and are being conducted in idealized as well as patient-derived geometries with the overarching goals of improving device design, facilitating treatment planning (what is the optimal device for a specific aneurysm), and predicting treatment outcome (will a specific aneurysm treated with a specific device successfully occlude over the long term). While the results are generally encouraging, there is poor standardization of study variables between different research groups, and any consensus will only be reached after standardized studies are conducted on collectively large datasets. Biochemical variables may have to be incorporated into these studies to maximize predictive values.

FIGURES IN THIS ARTICLE
<>
Copyright © 2017 by ASME
Your Session has timed out. Please sign back in to continue.

References

Dullien, F. A. L. , and Batra, V. K. , 1970, “ Determination of the Structure of Porous Media,” Ind. Eng. Chem., 62(10), pp. 25–53. [CrossRef]
Koponen, A. , Kataja, M. , and Timonen, J. , 1997, “ Permeability and Effective Porosity of Porous Media,” Phys. Rev. E, 56(3), pp. 3319–3325. [CrossRef]
Neithalath, N. , Sumanasooriya, M. S. , and Deo, O. , 2010, “ Characterizing Pore Volume, Sizes, and Connectivity in Pervious Concretes for Permeability Prediction,” Mater. Charact., 61(8), pp. 802–813. [CrossRef]
Jou, L. D. , Chintalapani, G. , and Mawad, M. E. , 2016, “ Metal Coverage Ratio of Pipeline Embolization Device for Treatment of Unruptured Aneurysms: Reality Check,” Interventional Neuroradiology, 22(1), pp. 42–48. [CrossRef] [PubMed]
Aenis, M. , Stancampiano, A. P. , Wakhloo, A. K. , and Lieber, B. B. , 1997, “ Modeling of Flow in a Straight Stented and Nonstented Side Wall Aneurysm Model,” ASME J. Biomech. Eng., 119(2), pp. 206–212. [CrossRef]
Lieber, B. B. , Stancampiano, A. P. , and Wakhloo, A. K. , 1997, “ Alteration of Hemodynamics in Aneurysm Models by Stenting: Influence of Stent Porosity,” Ann. Biomed. Eng., 25(3), pp. 460–469. [CrossRef] [PubMed]
Seong, J. , Wakhloo, A. K. , and Lieber, B. B. , 2007, “ In Vitro Evaluation of Flow Divertors in an Elastase-Induced Saccular Aneurysm Model in Rabbit,” ASME J. Biomech. Eng., 129(6), pp. 863–872. [CrossRef]
Stuhne, G. R. , and Steinman, D. A. , 2004, “ Finite-Element Modeling of the Hemodynamics of Stented Aneurysms,” ASME J. Biomech. Eng., 126(3), pp. 382–387. [CrossRef]
Kulcsar, Z. , Augsburger, L. , Reymond, P. , Pereira, V. M. , Hirsch, S. , Mallik, A. S. , Millar, J. , Wetzel, S. G. , Wanke, I. , and Rufenacht, D. A. , 2012, “ Flow Diversion Treatment: Intra-Aneurismal Blood Flow Velocity and WSS Reduction are Parameters to Predict Aneurysm Thrombosis,” Acta Neurochir., 154(10), pp. 1827–1834. [CrossRef]
Mut, F. , Raschi, M. , Scrivano, E. , Bleise, C. , Chudyk, J. , Ceratto, R. , Lylyk, P. , and Cebral, J. R. , 2015, “ Association Between Hemodynamic Conditions and Occlusion Times After Flow Diversion in Cerebral Aneurysms,” J. Neurointerventional Surg., 7(4), pp. 286–290. [CrossRef]
Larrabide, I. , Geers, A. J. , Morales, H. G. , Aguilar, M. L. , and Rufenacht, D. A. , 2015, “ Effect of Aneurysm and ICA Morphology on Hemodynamics Before and After Flow Diverter Treatment,” J. Neurointerventional Surg., 7(4), pp. 272–280. [CrossRef]
Rhee, K. , Han, M. H. , and Cha, S. H. , 2002, “ Changes of Flow Characteristics by Stenting in Aneurysm Models: Influence of Aneurysm Geometry and Stent Porosity,” Ann. Biomed. Eng., 30(7), pp. 894–904. [CrossRef] [PubMed]
Liou, T. M. , Liou, S. N. , and Chu, K. L. , 2004, “ Intra-Aneurysmal Flow With Helix and Mesh Stent Placement Across Side-Wall Aneurysm Pore of a Straight Parent Vessel,” ASME J. Biomech. Eng., 126(1), pp. 36–43. [CrossRef]
Sadasivan, C. , Fiorella, D. J. , Woo, H. H. , and Lieber, B. B. , 2013, “ Physical Factors Effecting Cerebral Aneurysm Pathophysiology,” Ann. Biomed. Eng., 41(7), pp. 1347–1365. [CrossRef] [PubMed]
Lieber, B. B. , Livescu, V. , Hopkins, L. N. , and Wakhloo, A. K. , 2002, “ Particle Image Velocimetry Assessment of Stent Design Influence on Intra-Aneurysmal Flow,” Ann. Biomed. Eng., 30(6), pp. 768–777. [CrossRef] [PubMed]
Yu, S. C. , and Zhao, J. B. , 1999, “ A Steady Flow Analysis on the Stented and Non-Stented Sidewall Aneurysm Models,” Med. Eng. Phys., 21(3), pp. 133–141. [CrossRef] [PubMed]
Seshadhri, S. , Janiga, G. , Beuing, O. , Skalej, M. , and Thevenin, D. , 2011, “ Impact of Stents and Flow Diverters on Hemodynamics in Idealized Aneurysm Models,” ASME J. Biomech. Eng., 133(7), p. 071005. [CrossRef]
Trager, A. L. , Sadasivan, C. , and Lieber, B. B. , 2012, “ Comparison of the In Vitro Hemodynamic Performance of New Flow Diverters for Bypass of Brain Aneurysms,” ASME J. Biomech. Eng., 134(8), p. 084505. [CrossRef]
Bouillot, P. , Brina, O. , Ouared, R. , Yilmaz, H. , Lovblad, K. O. , Farhat, M. , and Mendes Pereira, V. , 2016, “ Computational Fluid Dynamics With Stents: Quantitative Comparison With Particle Image Velocimetry for Three Commercial Off the Shelf Intracranial Stents,” J. Neurointerventional Surg., 8(3), pp. 309–315. [CrossRef]
Dennis, K. D. , Rossman, T. L. , Kallmes, D. F. , and Dragomir-Daescu, D. , 2015, “ Intra-Aneurysmal Flow Rates Are Reduced by Two Flow Diverters: An Experiment Using Tomographic Particle Image Velocimetry in an Aneurysm Model,” J. Neurointerventional Surg., 7(12), pp. 937–942. [CrossRef]
Roszelle, B. N. , Gonzalez, L. F. , Babiker, M. H. , Ryan, J. , Albuquerque, F. C. , and Frakes, D. H. , 2013, “ Flow Diverter Effect on Cerebral Aneurysm Hemodynamics: An In Vitro Comparison of Telescoping Stents and the Pipeline,” Neuroradiology, 55(6), pp. 751–758. [CrossRef] [PubMed]
Cebral, J. R. , Mut, F. , Raschi, M. , Hodis, S. , Ding, Y. H. , Erickson, B. J. , Kadirvel, R. , and Kallmes, D. F. , 2014, “ Analysis of Hemodynamics and Aneurysm Occlusion After Flow-Diverting Treatment in Rabbit Models,” AJNR, 35(8), pp. 1567–1573. [CrossRef] [PubMed]
Huang, Q. , Xu, J. , Cheng, J. , Wang, S. , Wang, K. , and Liu, J. M. , 2013, “ Hemodynamic Changes by Flow Diverters in Rabbit Aneurysm Models: A Computational Fluid Dynamic Study Based on Micro-Computed Tomography Reconstruction,” Stroke, 44(7), pp. 1936–1941. [CrossRef] [PubMed]
Ouared, R. , Larrabide, I. , Brina, O. , Bouillot, P. , Erceg, G. , Yilmaz, H. , Lovblad, K. O. , and Mendes Pereira, V. , “ Computational Fluid Dynamics Analysis of Flow Reduction Induced by Flow-Diverting Stents in Intracranial Aneurysms: A Patient-Unspecific Hemodynamics Change Perspective,” J. Neurointerventional Surg., epub.
Jing, L. , Zhong, J. , Liu, J. , Yang, X. , Paliwal, N. , Meng, H. , Wang, S. , and Zhang, Y. , 2016, “ Hemodynamic Effect of Flow Diverter and Coils in Treatment of Large and Giant Intracranial Aneurysms,” World Neurosurg., 89, pp. 199–207. [CrossRef] [PubMed]
Karmonik, C. , Chintalapani, G. , Redel, T. , Zhang, Y. J. , Diaz, O. , Klucznik, R. , and Grossman, R. G. , 2013, “ Hemodynamics at the Ostium of Cerebral Aneurysms With Relation to Post-Treatment Changes by a Virtual Flow Diverter: A Computational Fluid Dynamics Study,” 35th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), July 3–7, pp. 1895–1898.
Tsang, A. C. , Lai, S. S. , Chung, W. C. , Tang, A. Y. , Leung, G. K. , Poon, A. K. , Yu, A. C. , and Chow, K. W. , 2015, “ Blood Flow in Intracranial Aneurysms Treated With Pipeline Embolization Devices: Computational Simulation and Verification With Doppler Ultrasonography on Phantom Models,” Ultrasonography, 34(2), pp. 98–108. [CrossRef] [PubMed]
Kojima, M. , Irie, K. , Fukuda, T. , Arai, F. , Hirose, Y. , and Negoro, M. , 2012, “ The Study of Flow Diversion Effects on Aneurysm Using Multiple Enterprise Stents and Two Flow Diverters,” Asian J. Neurosurg., 7(4), pp. 159–165. [CrossRef] [PubMed]
Janiga, G. , Daroczy, L. , Berg, P. , Thevenin, D. , Skalej, M. , and Beuing, O. , 2015, “ An Automatic CFD-Based Flow Diverter Optimization Principle for Patient-Specific Intracranial Aneurysms,” J. Biomech., 48(14), pp. 3846–3852. [CrossRef] [PubMed]
Shobayashi, Y. , Tateshima, S. , Kakizaki, R. , Sudo, R. , Tanishita, K. , and Vinuela, F. , 2013, “ Intra-Aneurysmal Hemodynamic Alterations by a Self-Expandable Intracranial Stent and Flow Diversion Stent: High Intra-Aneurysmal Pressure Remains Regardless of Flow Velocity Reduction,” J. Neurointerventional Surg., 5(Suppl. 3), pp. iii38–iii42. [CrossRef]
Augsburger, L. , Reymond, P. , Rufenacht, D. A. , and Stergiopulos, N. , 2011, “ Intracranial Stents Being Modeled as a Porous Medium: Flow Simulation in Stented Cerebral Aneurysms,” Ann. Biomed. Eng., 39(2), pp. 850–863. [CrossRef] [PubMed]
Sadasivan, C. , Cesar, L. , Seong, J. , Wakhloo, A. K. , and Lieber, B. B. , 2009, “ Treatment of Rabbit Elastase-Induced Aneurysm Models by Flow Diverters: Development of Quantifiable Indexes of Device Performance Using Digital Subtraction Angiography,” IEEE Trans. Med. Imaging, 28(7), pp. 1117–1125. [CrossRef] [PubMed]
Grunwald, I. Q. , Kamran, M. , Corkill, R. A. , Kuhn, A. L. , Choi, I. S. , Turnbull, S. , Dobson, D. , Fassbender, K. , Watson, D. , and Gounis, M. J. , 2012, “ Simple Measurement of Aneurysm Residual After Treatment: The SMART Scale for Evaluation of Intracranial Aneurysms Treated With Flow Diverters,” Acta Neurochir., 154(1), pp. 21–26; Discussion 26. [CrossRef]
Joshi, M. D. , O'Kelly, C. J. , Krings, T. , Fiorella, D. , and Marotta, T. R. , 2013, “ Observer Variability of an Angiographic Grading Scale Used for the Assessment of Intracranial Aneurysms Treated With Flow-Diverting Stents,” AJNR, 34(8), pp. 1589–1592. [CrossRef] [PubMed]
Struffert, T. , Ott, S. , Kowarschik, M. , Bender, F. , Adamek, E. , Engelhorn, T. , Golitz, P. , Lang, S. , Strother, C. M. , and Doerfler, A. , 2013, “ Measurement of Quantifiable Parameters by Time-Density Curves in the Elastase-Induced Aneurysm Model: First Results in the Comparison of a Flow Diverter and a Conventional Aneurysm Stent,” Eur. Radiol., 23(2), pp. 521–527. [CrossRef] [PubMed]
Cho, Y. I. , and Kensey, K. R. , 1991, “ Effects of the Non-Newtonian Viscosity of Blood on Flows in a Diseased Arterial Vessel. Part 1: Steady Flows,” Biorheology, 28(3–4), pp. 241–262. https://www.researchgate.net/profile/Young_Cho5/publication/21222708_Effects_of_the_non-Newtonian_viscosity_of_blood_flows_in_a_diseased_arterial_vessel_Part_I_steady_flows/links/541ed8b90cf203f155c247b6.pdf [PubMed]
Ohta, M. , Wetzel, S. G. , Dantan, P. , Bachelet, C. , Lovblad, K. O. , Yilmaz, H. , Flaud, P. , and Rufenacht, D. A. , 2005, “ Rheological Changes After Stenting of a Cerebral Aneurysm: A Finite Element Modeling Approach,” Cardiovasc. Interventional Radiol., 28(6), pp. 768–772. [CrossRef]
Tateshima, S. , Jones, J. G. , Mayor Basto, F. , Vinuela, F. , and Duckwiler, G. R. , 2014, “ Aneurysm Pressure Measurement Before and After Placement of a Pipeline Stent: Feasibility Study Using a 0.014 Inch Pressure Wire for Coronary Intervention,” J. Neurointerventional Surg., 8(6), pp. 603–607. [CrossRef]
Augsburger, L. , Farhat, M. , Reymond, P. , Fonck, E. , Kulcsar, Z. , Stergiopulos, N. , and Rufenacht, D. A. , 2009, “ Effect of Flow Diverter Porosity on Intraaneurysmal Blood Flow,” Klin. Neuroradiologie, 19(3), pp. 204–214. [CrossRef]
Rayepalli, S. , Gupta, R. , Lum, C. , Majid, A. , and Koochesfahani, M. , 2013, “ The Impact of Stent Strut Porosity on Reducing Flow in Cerebral Aneurysms,” J. Neuroimaging, 23(4), pp. 495–501. [CrossRef] [PubMed]
Yu, C. H. , and Kwon, T. K. , 2014, “ Study of Parameters for Evaluating Flow Reduction With Stents in a Sidewall Aneurysm Phantom Model,” Biomed. Mater. Eng., 24(6), pp. 2417–2424. [PubMed]
Lee, C. J. , Srinivas, K. , and Qian, Y. , 2014, “ Three-Dimensional Hemodynamic Design Optimization of Stents for Cerebral Aneurysms,” Proc. Inst. Mech. Eng., Part H, 228(3), pp. 213–224. [CrossRef]
Brinjikji, W. , Murad, M. H. , Lanzino, G. , Cloft, H. J. , and Kallmes, D. F. , 2013, “ Endovascular Treatment of Intracranial Aneurysms With Flow Diverters: A Meta-Analysis,” Stroke, 44(2), pp. 442–447. [CrossRef] [PubMed]
Cebral, J. R. , Raschi, M. , Mut, F. , Ding, Y. H. , Dai, D. , Kadirvel, R. , and Kallmes, D. , 2014, “ Analysis of Flow Changes in Side Branches Jailed by Flow Diverters in Rabbit Models,” Int. J. Numer. Methods Biomed. Eng., 30(10), pp. 988–999. [CrossRef]
Hu, P. , Qian, Y. , Zhang, Y. , Zhang, H. Q. , Li, Y. , Chong, W. , and Ling, F. , 2015, “ Blood Flow Reduction of Covered Small Side Branches After Flow Diverter Treatment: A Computational Fluid Hemodynamic Quantitative Analysis,” J. Biomech., 48(6), pp. 895–898. [CrossRef] [PubMed]
Tang, A. Y. , Chung, W. C. , Liu, E. T. , Qu, J. Q. , Tsang, A. C. , Leung, G. K. , Leung, K. M. , Yu, A. C. , and Chow, K. W. , 2015, “ Computational Fluid Dynamics Study of Bifurcation Aneurysms Treated With Pipeline Embolization Device: Side Branch Diameter Study,” J. Med. Biol. Eng., 35(3), pp. 293–304. [CrossRef] [PubMed]
Makoyeva, A. , Bing, F. , Darsaut, T. E. , Salazkin, I. , and Raymond, J. , 2013, “ The Varying Porosity of Braided Self-Expanding Stents and Flow Diverters: An Experimental Study,” AJNR, 34(3), pp. 596–602. [CrossRef] [PubMed]
Karunanithi, K. , Lee, C. J. , Chong, W. , and Qian, Y. , 2015, “ The Influence of Flow Diverter's Angle of Curvature Across the Aneurysm Neck on Its Haemodynamics,” Proc. Inst. Mech. Eng., Part H, 229(8), pp. 560–569. [CrossRef]
Patel, N. V. , Gounis, M. J. , Wakhloo, A. K. , Noordhoek, N. , Blijd, J. , Babic, D. , Takhtani, D. , Lee, S. K. , and Norbash, A. , 2011, “ Contrast-Enhanced Angiographic Cone-Beam CT of Cerebrovascular Stents: Experimental Optimization and Clinical Application,” AJNR, 32(1), pp. 137–144. [PubMed]
Raymond, J. , Darsaut, T. E. , Bing, F. , Makoyeva, A. , Kotowski, M. , Gevry, G. , and Salazkin, I. , 2013, “ Stent-Assisted Coiling of Bifurcation Aneurysms May Improve Endovascular Treatment: A Critical Evaluation in an Experimental Model,” AJNR, 34(3), pp. 570–576. [CrossRef] [PubMed]
Gwilliam, M. N. , Hoggard, N. , Capener, D. , Singh, P. , Marzo, A. , Verma, P. K. , and Wilkinson, I. D. , 2009, “ MR Derived Volumetric Flow Rate Waveforms at Locations Within the Common Carotid, Internal Carotid, and Basilar Arteries,” J. Cereb. Blood Flow Metab., 29(12), pp. 1975–1982. [CrossRef] [PubMed]
Womersley, J. R. , 1955, “ Method for the Calculation of Velocity, Rate of Flow and Viscous Drag in Arteries When the Pressure Gradient is Known,” J. Physiol., 127(3), pp. 553–563. [CrossRef] [PubMed]
Bathe, K.-J. , and Bathe, K.-J. , 1996, Finite Element Procedures, Prentice Hall, Englewood Cliffs, NJ.
Fiorella, D. , Arthur, A. , Boulos, A. , Diaz, O. , Jabbour, P. , Pride, L. , Turk, A. S. , Woo, H. H. , Derdeyn, C. , Millar, J. , and Clifton, A. , 2016, “ Final Results of the U.S. Humanitarian Device Exemption Study of the Low-Profile Visualized Intraluminal Support (LVIS) Device,” J. Neurointerventional Surg., 8(9), pp. 894–897. [CrossRef]
Dholakia, R. , Drakopoulos, F. , Sadasivan, C. , Jiao, X. , Fiorella, D. J. , Woo, H. H. , Lieber, B. B. , and Chrisochoides, N. , 2015, “ High Fidelity Image-to-Mesh Conversion for Brain Aneurysm/Stent Geometries,” IEEE International Symposium on Biomedical Imaging. https://crtc.cs.odu.edu/pub/papers/conf_153.pdf
Foteinos, P. , and Chrisochoides, N. , 2013, “ High Quality Real-Time Image-to-Mesh Conversion for Finite Element Simulations,” 27th ACM International Conference on Supercomputing (ICS'13), pp. 233–242.
Foteinos, P. , and Chrisochoides, N. , 2014, “ High Quality Real-Time Image-to-Mesh Conversion for Finite Element Simulations,” J. Parallel Distrib. Comput., 74(2), pp. 2123–2140. [CrossRef]
Stewart, S. C. , Paterson, E. , Burgreen, G. , Hariharan, P. , Giarra, M. , Reddy, V. , Day, S. , Manning, K. , Deutsch, S. , Berman, M. , Myers, M. , and Malinauskas, R. , 2012, “ Assessment of CFD Performance in Simulations of an Idealized Medical Device: Results of FDA's First Computational Interlaboratory Study,” Cardiovasc. Eng. Technol., 3(2), pp. 139–160. [CrossRef]
Hariharan, P. , D'Souza, G. , Horner, M. , Malinauskas, R. A. , and Myers, M. R. , 2015, “ Verification Benchmarks to Assess the Implementation of Computational Fluid Dynamics Based Hemolysis Prediction Models,” ASME J. Biomech. Eng., 137(9), p. 094501. [CrossRef]
Trias, M. , Arbona, A. , Masso, J. , Minano, B. , and Bona, C. , 2014, “ FDA's Nozzle Numerical Simulation Challenge: Non-Newtonian Fluid Effects and Blood Damage,” PLoS One, 9(3), p. e92638. [CrossRef] [PubMed]
Steinman, D. A. , Hoi, Y. , Fahy, P. , Morris, L. , Walsh, M. T. , Aristokleous, N. , Anayiotos, A. S. , Papaharilaou, Y. , Arzani, A. , Shadden, S. C. , Berg, P. , Janiga, G. , Bols, J. , Segers, P. , Bressloff, N. W. , Cibis, M. , Gijsen, F. H. , Cito, S. , Pallares, J. , Browne, L. D. , Costelloe, J. A. , Lynch, A. G. , Degroote, J. , Vierendeels, J. , Fu, W. , Qiao, A. , Hodis, S. , Kallmes, D. F. , Kalsi, H. , Long, Q. , Kheyfets, V. O. , Finol, E. A. , Kono, K. , Malek, A. M. , Lauric, A. , Menon, P. G. , Pekkan, K. , Esmaily Moghadam, M. , Marsden, A. L. , Oshima, M. , Katagiri, K. , Peiffer, V. , Mohamied, Y. , Sherwin, S. J. , Schaller, J. , Goubergrits, L. , Usera, G. , Mendina, M. , Valen-Sendstad, K. , Habets, D. F. , Xiang, J. , Meng, H. , Yu, Y. , Karniadakis, G. E. , Shaffer, N. , and Loth, F. , 2013, “ Variability of Computational Fluid Dynamics Solutions for Pressure and Flow in a Giant Aneurysm: The ASME 2012 Summer Bioengineering Conference CFD Challenge,” ASME J. Biomech. Eng., 135(2), p. 021016.
Berg, P. , Roloff, C. , Beuing, O. , Voss, S. , Sugiyama, S. I. , Aristokleous, N. , Anayiotos, A. S. , Ashton, N. , Revell, A. , Bressloff, N. W. , Brown, A. G. , Chung, B. J. , Cebral, J. R. , Copelli, G. , Fu, W. , Qiao, A. , Geers, A. J. , Hodis, S. , Dragomir-Daescu, D. , Nordahl, E. , Suzen, Y. B. , Khan, M. O. , Valen-Sendstad, K. , Kono, K. , Menon, P. G. , Albal, P. G. , Mierka, O. , Munster, R. , Morales, H. G. , Bonnefous, O. , Osman, J. , Goubergrits, L. , Pallares, J. , Cito, S. , Passalacqua, A. , Piskin, S. , Pekkan, K. , Ramalho, S. , Marques, N. , Sanchi, S. , Schumacher, K. R. , Sturgeon, J. , Svihlova, H. , Hron, J. , Usera, G. , Mendina, M. , Xiang, J. , Meng, H. , Steinman, D. A. , and Janiga, G. , 2015, “ The Computational Fluid Dynamics Rupture Challenge 2013—Phase II: Variability of Hemodynamic Simulations in Two Intracranial Aneurysms,” ASME J. Biomech. Eng., 137(12), p. 121008. [CrossRef]
Chung, B. , Mut, F. , Kadirvel, R. , Lingineni, R. , Kallmes, D. F. , and Cebral, J. R. , 2015, “ Hemodynamic Analysis of Fast and Slow Aneurysm Occlusions by Flow Diversion in Rabbits,” J. Neurointerventional Surg., 7(12), pp. 931–935. [CrossRef]
Chong, W. , Zhang, Y. , Qian, Y. , Lai, L. , Parker, G. , and Mitchell, K. , 2014, “ Computational Hemodynamics Analysis of Intracranial Aneurysms Treated With Flow Diverters: Correlation With Clinical Outcomes,” AJNR, 35(1), pp. 136–142. [CrossRef] [PubMed]
Pereira, V. M. , Bonnefous, O. , Ouared, R. , Brina, O. , Stawiaski, J. , Aerts, H. , Ruijters, D. , Narata, A. P. , Bijlenga, P. , Schaller, K. , and Lovblad, K. O. , 2013, “ A DSA-Based Method Using Contrast-Motion Estimation for the Assessment of the Intra-Aneurysmal Flow Changes Induced by Flow-Diverter Stents,” AJNR, 34(4), pp. 808–815. [CrossRef] [PubMed]
Golitz, P. , Struffert, T. , Rosch, J. , Ganslandt, O. , Knossalla, F. , and Doerfler, A. , 2015, “ Cerebral Aneurysm Treatment Using Flow-Diverting Stents: In-Vivo Visualization of Flow Alterations by Parametric Colour Coding to Predict Aneurysmal Occlusion: Preliminary Results,” Eur. Radiol., 25(2), pp. 428–435. [CrossRef] [PubMed]
Malaspinas, O. , Turjman, A. , Ribeiro de Sousa, D. , Garcia-Cardena, G. , Raes, M. , Nguyen, P. T. , Zhang, Y. , Courbebaisse, G. , Lelubre, C. , Zouaoui Boudjeltia, K. , and Chopard, B. , 2016, “ A Spatio-Temporal Model for Spontaneous Thrombus Formation in Cerebral Aneurysms,” J. Theor. Biol., 394, pp. 68–76. [CrossRef] [PubMed]
Peach, T. W. , Ngoepe, M. , Spranger, K. , Zajarias-Fainsod, D. , and Ventikos, Y. , 2014, “ Personalizing Flow-Diverter Intervention for Cerebral Aneurysms: From Computational Hemodynamics to Biochemical Modeling,” Int. J. Numer. Methods Biomed. Eng., 30(11), pp. 1387–1407. [CrossRef]

Figures

Grahic Jump Location
Fig. 1

Simplified schematic of the therapeutic mechanism of flow diversion treatment for aneurysms. (a) An aneurysm is (b) treated by implantation of a flow diverter, which reduces flow activity within the aneurysm and (c) promotes clot formation within the aneurysm over hours to days; concurrently, a new arterial lining, called neointima, starts growing over the device. (d) Over weeks to months, the vessel remodels itself by resorbing the aneurysm along with completion of neointimal coverage of the device. While the aneurysm which is essentially a “dead-end” clots off, the natural pressure gradient maintains blood flow through side branches covered by the mesh.

Grahic Jump Location
Fig. 2

(a) The different mesh structures of a flow diverter (Pipeline, right) and an intracranial stent (Enterprise, left) contribute to the difference in function of the devices. (b) Theoretical variation of porosity and pore density based on deployment diameter for a “typical” flow diverter with 48 wires, about 30 μm wire diameter, in-air device diameter (dashed line) of 4 mm and approximately 70% porosity. These plots are characteristic of braided flow diverters. (c) Numerical simulation of a flow diverter deployed across a cavernous aneurysm shows the local variability that can exist in the pore structure at the aneurysm neck (inset: black border demarcates the aneurysm neck).

Grahic Jump Location
Fig. 3

(a) Computational fluid dynamics results (velocity magnitudes on top and vectors on bottom) of intra-aneurysmal flow during systole in a simplified sidewall aneurysm. The flow enters the distal neck in the unstented (control) case and forms a vortex within the aneurysm. Flow activity progressively reduces after implantation of a high-porosity stent (Neuroform) and a low-porosity stent (Pipeline). (b) Average velocity measures (as percentage of unstented cases) from a few literature reports. Decreasing porosity is seen to reduce flow activity; data toward the bottom of the plot are from sidewall-type geometries while those toward the top are from bifurcation-type geometries.

Grahic Jump Location
Fig. 4

Micro-CT slice of Pipeline in the aneurysm model (left) and the same slice after segmentation with the device wires cropped (right)

Grahic Jump Location
Fig. 5

(a) CAD model in position across the aneurysm neck (top row), and expanded view of the anisotropic tetrahedral mesh generated using meshing tools available within adina (bottom row): (a) Pipeline and (b) FRED devices

Grahic Jump Location
Fig. 6

Peak systolic speed distribution in the aneurysm (left) and velocity vector map (right) for (a) control, (b) Neuroform, (c) Enterprise, (d) LVIS, (e) FRED, and (f) Pipeline

Grahic Jump Location
Fig. 7

Instantaneous intra-aneurysmal kinetic energy throughout the cardiac beat for the five commercial neurovascular devices

Grahic Jump Location
Fig. 8

Comparison of intra-aneurysmal mean kinetic energies among five commercial neurovascular devices: (a) absolute values and (b) percent reductions as compared to control

Grahic Jump Location
Fig. 9

The effect of measured porosity and pore density on reduction in intra-aneurysmal mean kinetic energy

Grahic Jump Location
Fig. 10

Systolic velocity magnitudes in a right carotid superior hypophyseal (top) and a right carotid cavernous (bottom) aneurysm before (Pre) and after (Post) flow diversion treatment; the reductions in mean intraneurysmal kinetic energy (KE) are noted for each case

Tables

Errata

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In