Flow diverter effect of LVIS stent on cerebral aneurysm hemodynamics: a comparison with Enterprise stents and the Pipeline device
- Chao Wang†1, 2,
- Zhongbin Tian†1,
- Jian Liu1,
- Linkai Jing1,
- Nikhil Paliwal3, 4,
- Shengzhang Wang5,
- Ying Zhang1,
- Jianping Xiang3, 4,
- Adnan H. Siddiqui3, 6,
- Hui Meng3, 4 and
- Xinjian Yang1Email author
© The Author(s) 2016
Received: 22 January 2016
Accepted: 23 June 2016
Published: 2 July 2016
The aim of this study was to quantify the effect of the new Low-profile Visualized Intraluminal Support (LVIS®D) device and the difference of fluid diverting effect compared with the Pipeline device and the Enterprise stent using computational fluid dynamics (CFD).
In this research, we simulated three aneurysms constructed from 3D digital subtraction angiography (DSA). The Enterprise, LVIS and the Pipeline device were virtually conformed to fit into the vessel lumen and placed across the aneurysm orifice. Computational fluid dynamics analysis was performed to compare the hemodynamic differences such as WSS, Velocity and Pressure among these stents.
Control referred to the unstented model, the percentage of hemodynamic changes were all compared to Control. A single LVIS stent caused more wall shear stress reduction than double Enterprise stents (39.96 vs. 30.51 %) and velocity (23.13 vs. 18.64 %). Significant reduction in wall shear stress (63.88 %) and velocity (46.05 %) was observed in the double-LVIS stents. A single Pipeline showed less reduction in WSS (51.08 %) and velocity (37.87 %) compared with double-LVIS stent. The double-Pipeline stents resulted in the most reduction in WSS (72.37 %) and velocity (54.26 %). Moreover, the pressure increased with minuscule extent after stenting, compared with the unstented model.
This is the first study analyzing flow modifications associated with LVIS stents. We found that the LVIS stent has certain hemodynamic effects on cerebral aneurysms: a single LVIS stent caused more flow reductions than the double-Enterprise stent but less than a Pipeline device. Nevertheless, the double-LVIS stent resulted in a better flow diverting effect than a Pipeline device.
KeywordsComputational fluid dynamics (CFD) Wall shear stress (WSS) Intracranial aneurysm LVIS Hemodynamics
Endovascular stent-assisted coil embolization has been widely used for treatment of intracranial aneurysms. However, wide-necked, complex or dissecting aneurysms that incorporate a large portion of the parent artery can still be a challenge to treat and usually require scaffolding or bridging of the neck by special stents, combined with aneurysm coiling or flow diverters [1, 2]. The coil embolization refers to the filling of the aneurysm with coils and intracranial stents implanted in the parent artery is a porous tubular mesh made of nitinol or other alloys . The Enterprise, LVIS and Pipeline are three commercial stents to perform endovascular treatment, the LVIS stent provides a higher degree of metal coverage (approximately 23 %) which is more dense than the conventional Enterprise (8 %) but slightly lower than the Pipeline (approximately 30–35 %). To begin with, the “normal stent” such as Enterprise and LVIS refers to the stent with high porosity whose main function was avoiding coil herniation. Furthermore, the flow diverter (FD) as a special kind of stent is characterized with low porosity which has obvious hemodynamic effect on aneurysms, the pipeline device (PED) was also one of the typical flow diverters (FDs) in our research [4, 5].
The introduction and evolution of various stent systems has greatly broadened the applicability of endovascular therapy [6–9]. The Low-profile Visualized Intraluminal Support device (LVIS®D; MicroVention-Terumo, Tustin, CA, USA) is a novel, self-expandable braided stent with closed cell construction of nitinol material. The metal coverage(surface area covered by the stent) of the LVIS stent is significantly higher than the conventional Enterprise® (Cordis Neurovascular, Miami, Florida, USA) but slightly lower than the Pipeline (Coviden/ev3 Neurovascular, Irvine, CA, USA). Although this stent has been proved to be a safe and effective support device for stent-assisted coil embolization [10–12], there are no studies that evaluate the flow diversion effects of the LVIS stent. In previous studies, computational fluid dynamics (CFD) studies focused on flow diverting effects by comparing normal stent and FD [5, 13, 14]. However, it is necessary to evaluate the difference of hemodynamic effect among the novel LVIS stent, the conventional Enterprise stent and the PED as they are commonly used in the clinical practice. Moreover, in previous studies, the low porosity of flow diverters can be achieved by overlapping stents [4, 15]. Turner et al. reported three cases treated with LVIS stents and they deployed two LVIS stents to reconstruct the fusiform supraclinoid ICA in the case 2 . However, it was still unknown whether the overlapping LVIS stents could provide a similar hemodynamic effect to the PED. Therefore, we present quantitative data by comparing three kinds of commercially available stents: Enterprise, LVIS, and Pipeline in three patient–specific models. Moreover, we verify the differences of flow reduction effects between multiple LVIS stents and FDs.
We simulated three aneurysms constructed from 3D digital subtraction angiography (DSA). The aneurysms were stratified across the established size categories based on the International Subarachnoid Aneurysm Trial (ISAT), including small (≤10 mm), large (15–25 mm), and giant (≥25 mm). The size was measured on DSA. Case 1 involved a small aneurysm with a longitudinal diameter of 5.12 mm and a neck width of 5.08 mm. Case 2 involved a large aneurysm with a longitudinal diameter of 18.78 mm and a neck width of 11.18 mm. Case 3 involved a giant aneurysm with a longitudinal diameter of 25.16 mm and a neck width of 12.59 mm. The average diameter of the parent vessel is 3.76 mm (Case 1), 4.03 mm (Case 2), 4.19 mm (Case 3) respectively. The medical data were gathered for diagnostic purposes, and the study was approved by the Ethics Committee of our institution.
Stent modeling and deployment
Computational fluid dynamics modeling was performed by numerically solving the continuity and Navier–Stokes momentum equations for an unsteady blood flow using the commercial software ANSYS CFX 14.0 (ANSYS, Inc., Canonsburg, PA), based on the finite volume method. Fluid volumetric mesh was created and defined by ANSYS ICEM for our simulations. For this calculation, mesh dependency tests were performed to ensure the stability of the simulations; the final grids contained approximately 2 million to 50 million tetrahedral elements for the untreated and stented models. Blood was assumed as an incompressible Newtonian fluid with a density of 1060 kg/m3 and a viscosity of 0.004 kg/m/s. Because patient-specific information was not available in the simulations, pulsatile boundary conditions were based on superposition of blood-flow waveforms of the common internal carotid artery using Doppler ultrasonography in normal human subjects for transient analysis. Vessel walls were assumed to be rigid, and no-slip boundary conditions were applied at the lumens. The pressure distribution along the parent artery and in the aneurysm was then computed using the decreases in pressure calculated during the CFD simulations with respect to the P = 10,000 Pa value prescribed at the outlet . Physiologic flow waveforms measured by transcranial doppler were pulsatile. Therefore, the flow data such as (velocity, flow rate and OSS) will change in the whole cardiac cycle. But the patient-specific flow data were not always available in clinical practice, we have to use the representative population average value (1.5 Pa) [22, 23] to eliminate the bias resulted from individual difference. The flow waveforms were scaled to achieve a mean inlet Wall Shear Stress (WSS) over the entire cycle of 1.5 Pa under pulsatile conditions. The unsteady flow solutions were advanced in time using 0.001 s for two cycles with a fully implicit scheme and efficient solution algorithms . Results of the second cycle were used for hemodynamic aneurysm characterization, (e.g., the WSS). Wall shear stress is a tangential drag force per unit area of endothelial surface Aneurysm pressure and the velocity of the perpendicular plane (perpendicular to the aneurysm inlet/neck) of the aneurysm corresponding to the pre-and post-implantation models were calculated and compared at the systolic peak.
The hemodynamic values for the control
The LVIS stent, regarded as a novel self-expandable stent of smaller cell size (~0.9 mm) than currently available coil-assist stents [11, 16], has been used successfully to treat wide-necked and dissecting aneurysms [25, 26]. It may provide better protection against coil protrusion and yields improved flow diversion. Furthermore, the LVIS stent is well-visualized throughout its course, owing to dual radiopaque helical strands . The Food and Drug Administration (FDA) and the management of our country set the indication of Pipeline device (PED) to treat large or giant wide-necked intracranial aneurysms in the internal carotid artery from the petrous to the superior hypophyseal segments . However, in addition to the indication of PED, the novel LVIS stent also offer promise in treating more types and locations (especially for the posterior circulation) of aneurysms compared with the PED [28, 29]. The LVIS stent is denser than the conventional Enterprise stent, the porosity of the stent is of key importance for hemodynamic modifications as it controls resistance to blood flow through the interwire gaps, thereby allowing the possibility of flow stasis in the aneurysm; hence promoting rapid thrombosis [30–32] Moreover, the intra-aneurysm thrombosis after embolization could be hampered by high-speed flow and high WSS while the stent could decrease the flow velocity and the WSS [18, 33, 34]. So it is necessary to evaluate the difference of hemodynamic effect between the LVIS stent and the Enterprise stent. Therefore, our purpose was to measure the effects of the LVIS stent on aneurysm hemodynamics and to quantify the difference when the LVIS stent was compared with the Pipeline device and the Enterprise stent. It would be helpful to enhance current understanding of these stents and how they can best be used to treat cerebral aneurysms which would provide some reference information for physicians.
Currently, there is a lot of research interest on hemodynamic changes associated with flow diverters and multiple conventional stents. Tremmel et al.  simulated the various combinations of one to three conventional Enterprise or Vision stents and demonstrated a 14.1 and 28.7 % WSS reduction with a single Enterprise and double Enterprise stent, which is similar to our study. The WSS reduction of a single Enterprise and double-Enterprise were 12.72 and 30.51 % respectively. Levitt et al.  demonstrated that aneurysm treatment with a Pipeline device reduced blood flow and hemodynamic shear stress in the aneurysm dome and that the WSS at the moment of peak systole was reduced by 51.89 %, similar to our results (51.08 %). Kojima et al.  virtually modeled three kinds of commercially available intracranial stents (Enterprise, Silk and Pipeline) in an intracranial ophthalmic artery aneurysm. Consistent with our results, they also showed that the reduced velocity within the aneurysm sac with a double Enterprise stent is not as significant as the flow diverters. However, no study has quantified the effect of the LVIS stent on aneurysm hemodynamics, although the LVIS stent has generated good clinical improvement with high levels of occlusion and low rates of recanalization . In our study, the single LVIS stent caused more flow reductions than the double Enterprise stent, but less than the Pipeline device. Nevertheless, the double LVIS stent resulted in a better flow diverting effect than a Pipeline device. Finally, we found that the LVIS stent has certain hemodynamic effects (obvious reductions in WSS and velocity) on cerebral aneurysms compared with the Enterprise and Pipeline stents.
In the practical daily clinical setting, it is very difficult to quantify the hemodynamic effects of stents, because of multiple uncertainties and fluctuating factors. Furthermore, a real case can only be treated with only one option in clinical practice, so we would have been unable to simulate all stents or flow diverters in identical cases. However, in virtual models, we can use the virtual stenting technology to compare the options before the interventionist actually performs the procedure. In our study, we virtually modeled three kinds of commercially available intracranial stents (LVIS, Pipeline and Enterprise). Kojima et al. demonstrated that the mesh characteristics, like size and pore density affected the blood flow in the aneurysm . In other words, the reduction effect of velocity and wall shear stress is in proportion to the stent’s metal coverage. The biological basis for the reduction may be that the stent mesh could block the blood into aneurysm and break intra-aneurysmal blood circulation, which leads to decrease of intra-aneurysmal velocity and thereby allowing the possibility of flow stasis in the aneurysm, hence increasing blood viscosity and promoting rapid thrombosis . Then neointima gradually formed over the stent surface to completely exclude the aneurysm from the circulation . Ultimately, the aneurysm was cured. However, Xiang et al. found a large hemodynamic difference between two adjacent aneurysms in case 3 after a single pipeline implantation despite identical metal coverage . Therefore, although the metal coverage was known, it was also necessary to quantify the hemodynamic factors.
In our study, we verified the differences of flow reduction effect for aneurysms after stent placement and the results showed that a single LVIS placement was better than a double Enterprise stent in reducing the velocity and WSS of the aneurysm sac. We also found that a double-LVIS stent was better than a single Pipeline device and that there was a pressure increase after stenting but this change was minuscule for all the stents. The decreased flow velocity could be indicative of stagnant blood flow, which can promote thrombosis. Wall shear stress has been found to play an important role in the recurrence of aneurysms [37, 38]. Areas with low velocity and WSS are subject to increased chance of thrombus [20, 24]. High-flow conditions may significantly contribute to aneurysm recanalization via multiple mechanisms. To begin with, intra-aneurysm thrombosis after embolization could be hampered by high-speed flow and high WSS [33, 34]. Furthermore, high blood flow at the treated aneurysm neck may delay neointima formation over the stent surface and lead to coil compaction seen at follow-up [39, 40]. In the previous studies, many researchers [18, 36, 41] have focused on the flow diversion properties after stenting to evaluate the recurrence risk and found that an emerging or residual local high WSS or velocity were prone to future recanalization. However, these studies based on a small sample could not provide accurate gold standard values to predict the late recurrence and we only performed a relevance research to evaluate hemodynamic changes after stenting. Further study based on a large sample should devote more attention to identify the gold standard values. The main finding of our study was a decreased velocity and WSS after stent placement. We also quantified the differences of flow reduction effect for aneurysms after stent placement and the results, indicating a reduced risk of recurrence. It would be beneficial to choose appropriate therapeutic schedule in clinical practice. Meanwhile, sub-3 % pressure increase after stenting may be due to several reasons: when the stent was implanted, the flow resistance increased, the outlet pressure in our computational models was set to be a constant 10,000 Pa, the pressure at the inlet and the aneurysm increased in order to keep the flow rate steady; moreover, according to the Bernoulli’s Principle, the reduced velocity in the aneurysm would increase pressure after stenting; the increment of pressure inside the aneurysm was small compared to 10,000 Pa, thus the pressure change after stenting was minuscule.
This study has several limitations. First, the flow simulation of three patient-specific aneurysms with different stent configuration and the hemodynamic parameters in peak systole may not be sufficient to demonstrate generalized results. It is necessary to gather more data on large numbers of aneurysms of various sizes and morphologies. Second, the mechanisms of aneurysm occlusion cannot be explained simply by hemodynamics, other factors such as biological factors (blood residence time) in pathophysiology are also indispensable. Third, the resulting pattern of overlapping wires and cells would vary if one stent was deployed inside the other, which makes overlapping stents unpredictable. Last, several assumptions, such as rigid wall, laminar flow, Newtonian blood, and constant pressure at outlets may affect the hemodynamic results.
This is the first study analyzing flow modifications associated with placement of LVIS stents. In our study, a single LVIS stent caused more flow reductions than the double-Enterprise stent but less than a Pipeline device. Nevertheless, the double-LVIS stent resulted in a better flow diverting effect than a Pipeline device.
computational fluid dynamics
wall shear stress
Low-Profile Visualized Intraluminal Support
the pipeline device
CW and ZT performed the statistical analysis and the manuscript writing. NP and JX made critical revision to the manuscript for important intellectual content. SW and YZ were responsible for aneurysmal model reconstruction and analyzed and interpreted the data. AS and HM was responsible for in-house software exploitation. JL and LJ acquired the data. XY conceived and designed the research, and handled funding and supervision. All authors read and approved the final manuscript.
The authors declare that they have no competing interests.
Availability of data and materials section
The dataset(s) supporting the conclusions of this article is (are) included within the article. All clinical data are stored by information system at Department of Interventional Neuroradiology, Beijing Neurosurgical Institute and Beijing Tian Tan Hospital, Capital Medical University.
Ethics approval and consent to participate
The research was permitted by the ethics committee of Beijing Tian Tan Hospital and written informed consents were obtained from all patients.
This work was supported by National Natural Science Foundation of China (Grant Nos. 81301003, 81171079, 81371315, 81471167 and 81220108007), Special Research Project for Capital Health Development (Grant No.2014-1-1071) and National Institutes of Health (R01 NS091075).
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- Geyik S, Yavuz K, Yurttutan N, Saatci I, Cekirge HS. Stent-assisted coiling in endovascular treatment of 500 consecutive cerebral aneurysms with long-term follow-up. AJNR Am J Neuroradiol. 2013;34:2157–62.View ArticlePubMedGoogle Scholar
- Brinjikji W, Murad MH, Lanzino G, Cloft HJ, Kallmes DF. Endovascular treatment of intracranial aneurysms with flow diverters: a meta-analysis. Stroke. 2013;44:442–7.View ArticlePubMedGoogle Scholar
- Larrabide I, Kim M, Augsburger L, Villa-Uriol MC, Rufenacht D, Frangi AF. Fast virtual deployment of self-expandable stents: method and in vitro evaluation for intracranial aneurysmal stenting. Med Image Anal. 2012;16:721–30.View ArticlePubMedGoogle Scholar
- Roszelle BN, Gonzalez LF, Babiker MH, Ryan J, Albuquerque FC, Frakes DH. Flow diverter effect on cerebral aneurysm hemodynamics: an in vitro comparison of telescoping stents and the Pipeline. Neuroradiology. 2013;55:751–8.View ArticlePubMedGoogle Scholar
- Kojima M, Irie K, Fukuda T, Arai F, Hirose Y, Negoro M. The study of flow diversion effects on aneurysm using multiple enterprise stents and two flow diverters. Asian J Neurosurg. 2012;7:159–65.View ArticlePubMedPubMed CentralGoogle Scholar
- Benitez RP, Silva MT, Klem J, Veznedaroglu E, Rosenwasser RH. Endovascular occlusion of wide-necked aneurysms with a new intracranial microstent (Neuroform) and detachable coils. Neurosurgery. 2004;54:1359–67 (discussion 1368).View ArticlePubMedGoogle Scholar
- Fiorella D, Albuquerque FC, Deshmukh VR. Usefulness of the Neuroform stent for the treatment of cerebral aneurysms: results at initial (3-6-mo) follow-up. Neurosurgery. 2005;56:1191–201 (discussion 1201-1192).View ArticlePubMedGoogle Scholar
- Mocco J, Snyder KV, Albuquerque FC, Bendok BR, Alan SB, Carpenter JS, Fiorella DJ, Hoh BL, Howington JU, Jankowitz BT, et al. Treatment of intracranial aneurysms with the enterprise stent: a multicenter registry. J Neurosurg. 2009;110:35–9.View ArticlePubMedGoogle Scholar
- Weber W, Bendszus M, Kis B, Boulanger T, Solymosi L, Kuhne D. A new self-expanding nitinol stent (Enterprise) for the treatment of wide-necked intracranial aneurysms: initial clinical and angiographic results in 31 aneurysms. Neuroradiology. 2007;49:555–61.View ArticlePubMedGoogle Scholar
- Poncyljusz W, Bilinski P, Safranow K, Baron J, Zbroszczyk M, Jaworski M, Bereza S, Burke TH. The LVIS/LVIS Jr. stents in the treatment of wide-neck intracranial aneurysms: multicentre registry. J Neurointerv Surg. 2015;7:524–9.View ArticlePubMedGoogle Scholar
- Behme D, Weber A, Kowoll A, Berlis A, Burke TH, Weber W. Low-profile Visualized Intraluminal Support device (LVIS Jr) as a novel tool in the treatment of wide-necked intracranial aneurysms: initial experience in 32 cases. J Neurointerv Surg. 2015;7:281–5.View ArticlePubMedGoogle Scholar
- Mohlenbruch M, Herweh C, Behrens L, Jestaedt L, Amiri H, Ringleb PA, Bendszus M, Pham M. The LVIS Jr. microstent to assist coil embolization of wide-neck intracranial aneurysms: clinical study to assess safety and efficacy. Neuroradiology. 2014;56:389–95.View ArticlePubMedGoogle Scholar
- Tremmel M, Xiang J, Natarajan SK, Hopkins LN, Siddiqui AH, Levy EI, Meng H. Alteration of intra-aneurysmal hemodynamics for flow diversion using enterprise and vision stents. World Neurosurg. 2010;74:306–15.View ArticlePubMedPubMed CentralGoogle Scholar
- Levitt MR, McGah PM, Aliseda A, Mourad PD, Nerva JD, Vaidya SS, Morton RP, Ghodke BV, Kim LJ. Cerebral aneurysms treated with flow-diverting stents: computational models with intravascular blood flow measurements. AJNR Am J Neuroradiol. 2014;35:143–8.View ArticlePubMedGoogle Scholar
- 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. 2011;39:850–63.View ArticlePubMedGoogle Scholar
- Turner RD, Turk A, Chaudry I. Low-profile visible intraluminal support device: immediate outcome of the first three US cases. J Neurointerv Surg. 2013;5:157–60.View ArticlePubMedGoogle Scholar
- Paliwal N, Yu H, Damiano R, Xiang J, Yang X, Siddiqui A, Li H, Meng H. Fast virtual stenting with vessel-specific initialization and collision detection. In: ASME 2014 International design engineering technical conferences and computers and information in engineering conference 2014. pp. V003T12A014–V003T12A014. American Society of Mechanical Engineers.
- Liu J, Jing L, Wang C, Paliwal N, Wang S, Zhang Y, Xiang J, Siddiqui AH, Meng H, Yang X. Effect of hemodynamics on outcome of subtotally occluded paraclinoid aneurysms after stent-assisted coil embolization. J Neurointerv Surg. 2015.
- Delingette H. General object reconstruction based on simplex meshes. Int J Comput Vision. 1999;32:111–46.View ArticleGoogle Scholar
- Bernardini A, Larrabide I, Morales HG, Pennati G, Petrini L, Cito S, Frangi AF. Influence of different computational approaches for stent deployment on cerebral aneurysm haemodynamics. Interface Focus. 2011;1:338–48.View ArticlePubMedPubMed CentralGoogle Scholar
- Kim M, Taulbee DB, Tremmel M, Meng H. Comparison of two stents in modifying cerebral aneurysm hemodynamics. Ann Biomed Eng. 2008;36:726–41.View ArticlePubMedPubMed CentralGoogle Scholar
- Cebral JR, Castro MA, Putman CM, Alperin N. Flow-area relationship in internal carotid and vertebral arteries. Physiol Meas. 2008;29:585–94.View ArticlePubMedPubMed CentralGoogle Scholar
- Lovblad KO, Yilmaz H, Chouiter A, San Millan Ruiz D, Abdo G, Bijlenga P, de Tribolet N, Ruefenacht DA. Intracranial aneurysm stenting: follow-up with MR angiography. J Magn Reson Imaging. 2006;24:418–22.View ArticlePubMedGoogle Scholar
- Mut F, Aubry R, Lohner R, Cebral JR. Fast numerical solutions of patient-specific blood flows in 3D arterial systems. Int J Numer Method Biomed Eng. 2010;26:73–85.View ArticlePubMedPubMed CentralGoogle Scholar
- Poncyljusz W, Bilinski P, Safranow K, Baron J, Zbroszczyk M, Bereza S, Burke TH. The LVIS/LVIS Jr. stents in the treatment of wide-neck intracranial aneurysms: multicentre registry. J Neurointerv Surg. 2014.
- Cho YD, Sohn CH, Kang HS, Kim JE, Cho WS, Hwang G, Kwon OK, Ko MS, Park NM, Han MH. Coil embolization of intracranial saccular aneurysms using the Low-profile Visualized Intraluminal Support (LVIS) device. Neuroradiology. 2014;56:543–51.View ArticlePubMedGoogle Scholar
- US Food and Drug Administration: Pipeline embolization device PMA P100018. Summary of safety and effectiveness data. 2011.
- Conrad MD, Brasiliense LB, Richie AN, Hanel RA. Y stenting assisted coiling using a new low profile visible intraluminal support device for wide necked basilar tip aneurysms: a technical report. J Neurointerv Surg. 2014;6:296–300.View ArticlePubMedGoogle Scholar
- US Food and Drug Administrationx:Low-Profile Visualized Intraluminal Support Device (LVIS and LVIS Jr.)—H130005. Summary of safety and probable benefit. 2011.
- Seshadhri S, Janiga G, Beuing O, Skalej M, Thevenin D. Impact of stents and flow diverters on hemodynamics in idealized aneurysm models. J Biomech Eng. 2011;133:071005.View ArticlePubMedGoogle Scholar
- Palmaz JC. Intravascular stents: tissue-stent interactions and design considerations. AJR Am J Roentgenol. 1993;160:613–8.View ArticlePubMedGoogle Scholar
- Wakhloo AK, Tio FO, Lieber BB, Schellhammer F, Graf M, Hopkins LN. Self-expanding nitinol stents in canine vertebral arteries: hemodynamics and tissue response. AJNR Am J Neuroradiol. 1995;16:1043–51.PubMedGoogle Scholar
- Byun HS, Rhee K. CFD modeling of blood flow following coil embolization of aneurysms. Med Eng Phys. 2004;26:755–61.View ArticlePubMedGoogle Scholar
- Rayz VL, Boussel L, Lawton MT, Acevedo-Bolton G, Ge L, Young WL, Higashida RT, Saloner D. Numerical modeling of the flow in intracranial aneurysms: prediction of regions prone to thrombus formation. Ann Biomed Eng. 2008;36:1793–804.View ArticlePubMedPubMed CentralGoogle Scholar
- Fischer S, Vajda Z, Aguilar Perez M, Schmid E, Hopf N, Bazner H. Pipeline embolization device (PED) for neurovascular reconstruction: initial experience in the treatment of 101 intracranial aneurysms and dissections. Neuroradiology. 2012;54:369–82.View ArticlePubMedGoogle Scholar
- Xiang J, Damiano RJ, Lin N, Snyder KV, Siddiqui AH, Levy EI, Meng H. High-fidelity virtual stenting: modeling of flow diverter deployment for hemodynamic characterization of complex intracranial aneurysms. J Neurosurg. 2015;123:832–40.View ArticlePubMedPubMed CentralGoogle Scholar
- Li C, Wang S, Chen J, Yu H, Zhang Y, Jiang F, Mu S, Li H, Yang X. Influence of hemodynamics on recanalization of totally occluded intracranial aneurysms: a patient-specific computational fluid dynamic simulation study. J Neurosurg. 2012;117:276–83.View ArticlePubMedGoogle Scholar
- Luo B, Yang X, Wang S, Li H, Chen J, Yu H, Zhang Y, Zhang Y, Mu S, Liu Z, Ding G. High shear stress and flow velocity in partially occluded aneurysms prone to recanalization. Stroke. 2011;42:745–53.View ArticlePubMedGoogle Scholar
- Cha KS, Balaras E, Lieber BB, Sadasivan C, Wakhloo AK. Modeling the interaction of coils with the local blood flow after coil embolization of intracranial aneurysms. J Biomech Eng. 2007;129:873–9.View ArticlePubMedGoogle Scholar
- Meng H, Wang Z, Hoi Y, Gao L, Metaxa E, Swartz DD, Kolega J. Complex hemodynamics at the apex of an arterial bifurcation induces vascular remodeling resembling cerebral aneurysm initiation. Stroke. 2007;38:1924–31.View ArticlePubMedPubMed CentralGoogle Scholar
- Kono K, Shintani A, Terada T. Hemodynamic effects of stent struts versus straightening of vessels in stent-assisted coil embolization for sidewall cerebral aneurysms. PLoS One. 2014;9:e108033.View ArticlePubMedPubMed CentralGoogle Scholar