The Role of Hemodynamics in Intracranial Bifurcation Arteries after Aneurysm Treatment with Flow-Diverter Stents

Narata, Ana Paula; Moura, Fernando Silva de; Larrabide, Ignacio; Perrault, Cécile M.; Patat, F.; Bibi, R; Velasco, Stéphane; Januel, Anne-Christine; Cognard, Christophe; Chapot, René; Bouakaz, Ayache; Sennoga, Charles A.; Marzo, Alberto

doi:10.3174/ajnr.a5471

Cited by 10 publications

(12 citation statements)

References 30 publications

(36 reference statements)

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“…The aim of the study was to investigate, for a cohort of 142 aneurysm datasets, the role of resistance to flow in flow changes induced by FDS treatment that may relate to vessel narrowing/occlusion in a subacute phase. The effect of FDS on flow distribution at symmetric and asymmetric bifurcations has been studied previously, but this was compared with a small number of cases (25), which was not enough to explain the changes in vessel diameter 13…”

Section: Discussionmentioning

confidence: 99%

“…Blood was assumed incompressible (density ρ =1050 kg/m 3 ) and Newtonian (viscosity μ =0.0035 Pa.s). Appropriateness of modeling approaches and accuracy of the numerical solutions were ensured by adopting methodologies that we have previously reported 13 18 20 21. The mesh used for the unstented model comprised approximately 0.8 million nodes (4 million nodes for the stented model) and 2.7 million elements (19 million elements for the stented model), resulting in a mesh volumetric density of 2.7 thousand elements per mm 3 (19 thousand elements per mm 3 for the stented model).…”

Section: Methodsmentioning

confidence: 99%

“…Narrowing and occlusion are a common event after a FDS procedure for middle cerebral artery (MCA) and some anterior cerebral artery (ACA) bifurcation aneurysms (MCA and ACA bifurcations without opposite A1), and anatomic parameters could be involved in hemodynamic changes that affect the vessel wall. Asymmetry of branches, hemodynamic alterations, and clinical outcome after treatment with FDS for bifurcation aneurysms have been correlated in a study that identified an anatomic threshold of the daughter vessel diameter ratio (0.7) below which FDS-induced alterations of volumetric flow rates and significant changes in wall shear stress (WSS) correlate with poor clinical outcome 13. It is difficult to apply this theory to proximal ICA aneurysms because the ratio of OphthA to ICA is lower than 0.7, and a jailed OphthA remains mostly patent.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Role of distal cerebral vasculature in vessel constriction after aneurysm treatment with flow diverter stents

Narata

Moura

Larrabide

et al. 2020

J NeuroIntervent Surg

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BackgroundTreatment of intracranial aneurysms with flow diverter stent (FDS) procedures can lead to caliber changes of jailed vessels. The reason some branches remain unchanged and others are affected by narrowing remains unknown.ObjectiveTo investigate the influence of resistance to flow from distal vasculature on stent-induced hemodynamic modifications affecting bifurcating vessels.Materials and methodsRadiological images and demographic data were acquired for 142 aneurysms treated with a FDS. Vascular resistance was estimated from patient-specific anatomic data. Correlation analysis was used to identify correspondence between anatomic data and clinical outcome. Computational Fluid Dynamics was performed on a typical patient-specific model to evaluate the influence of FDS on flow. Relevant hemodynamic variables along the bifurcating vessels were quantitatively analyzed and validated with in vitro data obtained using power Doppler ultrasound.ResultsStatistical analysis showed a correlation between clinical outcome and FDS resistance to flow considering overall jailed vessel vascular resistance (r=0.5, P<0.001). Computational predictions of blood flow showed that hemodynamics is minimally affected by FDS treatment in the ophthalmic artery.ConclusionsJailed vessels are affected by narrowing when resistance to flow from the FDS constitutes a larger proportion of the overall vessel resistance to flow. This knowledge may contribute to better understanding of intracranial hemodynamics after a FDS procedure and reinforce indications for flow diversion in the treatment of intracranial aneurysms.

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Role of distal cerebral vasculature in vessel constriction after aneurysm treatment with flow diverter stents

Narata

Moura

Larrabide

et al. 2020

J NeuroIntervent Surg

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“…[6,13] Other researchers present data supporting the fact that asymmetrical distal vessels (daughter vessels) influence the flow dynamics in the area of a bifurcation. [4,17] As a result, it could be assumed that this is associated with a higher incidence of aneurysm development at the affected bifurcations. To further support this, Zhang et al demonstrated in 2019 that asymmetric MCA bifurcations are more susceptible to the development of aneurysms.…”

Section: Discussionmentioning

confidence: 99%

Asymmetry of P1 and vertebral arteries is not related to basilar tip aneurysm development or rupture

Hofmann

Fischer

et al. 2020

Acta Neurochir

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Objective Lately, morphological parameters of the surrounding vasculature aside from aneurysm size, specific for the aneurysm location, e.g., posterior cerebral artery angle for basilar artery tip aneurysms, could be identified to correlate with the risk of rupture. We examined further image-based morphological parameters of the aneurysm surrounding vasculature that could correlate with the growth or the risk of rupture of basilar artery tip aneurysms. Methods Data from 83 patients with basilar tip aneurysms (27 not ruptured; 56 ruptured) and 100 control patients were assessed (50 without aneurysms and 50 with aneurysms of the anterior circle of Willis). Anatomical parameters of the aneurysms were assessed and analyzed, as well as of the surrounding vasculature, namely the asymmetry of P1 and the vertebral arteries. Results Patients with basilar tip aneurysm showed no significant increase in P1 or vertebral artery asymmetry compared with the control patients or patients with aneurysms of the anterior circulation, neither was there a significant difference in asymmetry between cases with ruptured and unruptured aneurysms. Furthermore, we observed no significant correlations between P1 asymmetry and the aneurysm size or number of lobuli in the aneurysms. Conclusion We observed no significant difference in aneurysm size, rupture, or lobulation associated with P1 or vertebral artery (surrounding vasculature) asymmetry. Therefore, the asymmetry of the surrounding vessels does not seem to be a promising morphological parameter for the evaluation of probability of rupture and growth in basilar tip aneurysms in future studies.

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“…As 0-D models are less costly than 1-D models, a Windkessel model is often used to provide boundary conditions for 1-D blood flow simulation [46,47,52]. A coupling of a 1-D and 3-element Windkessel model proposed by Reymond et al [47] was adopted in several studies on aneurysm CFD for the purpose of specifying boundary conditions [53][54][55]. Another way to utilise a 0-D model is to acquire outflow boundary conditions for 3-D haemodynamic simulation directly, not via any 1-D model.…”

Section: Reduced-order Modelsmentioning

confidence: 99%

Understanding of boundary conditions imposed at multiple outlets in computational haemodynamic analysis of cerebral aneurysm

et al. 2019

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Computational fluid dynamics (CFD) is considered to be a promising tool for haemodynamic analysis of the intracranial aneurysm. However, aneurysm CFD is still not regarded as fully reliable mainly because the computational result is influenced by too many factors such as the luminal geometry of the model, spatiotemporal resolutions and boundary conditions. Among the influential factors, this paper focuses on outflow boundary conditions used when the computational domain has multiple outlets. Four outflow strategies found in published articles are reviewed: 1) prescription of constant or zero pressure, 2) flow splitting based on the power law, 3) traction-free and zero velocitygradient conditions and 4) coupling of CFD with a reducedorder model. None of them has proved definitely superior or inferior to others. For accurate quantification of the haemodynamic state in the aneurysm, it is crucial to incorporate the physiologically correct flow splitting ratio in CFD analysis by means of accurate specification of pressure or flow rate at the outlets. A coupling of CFD and a 0-d model (a subtype of the reduced-order model) appears to be the most promising although further study is necessary to achieve accurate estimation of model parameters.

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The Role of Hemodynamics in Intracranial Bifurcation Arteries after Aneurysm Treatment with Flow-Diverter Stents

Cited by 10 publications

References 30 publications

Role of distal cerebral vasculature in vessel constriction after aneurysm treatment with flow diverter stents

Role of distal cerebral vasculature in vessel constriction after aneurysm treatment with flow diverter stents

Asymmetry of P1 and vertebral arteries is not related to basilar tip aneurysm development or rupture

Understanding of boundary conditions imposed at multiple outlets in computational haemodynamic analysis of cerebral aneurysm

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