title: Changes in hemodynamics after placing intracranial stents.
abstract: Stent-assisted coil embolization has enabled the endovascular treatment of wide-necked cerebral aneurysms. Moreover, recent reports demonstrated that stent-assisted coil embolization was associated with a significant decrease in angiographic recurrences of coiled cerebral aneurysms. One of the possible explanations for this adjunctive effect of stent-assisted coil embolization is changes in the local hemodynamics caused by placing intracranial stents. This study investigated the hemodynamic effect of intracranial stents using computational fluid dynamics (CFD) analysis. The geometry of the intracranial stent, Enterprise(TM) VRD, was acquired by using micro computed tomography and virtually placed across the aneurysm orifice of a saccular aneurysm model (saccular model) and a blister-like aneurysm model (blister-like model) constructed from patient-specific three-dimensional (3D) rotational angiography data. Transient CFD analysis was performed with these models with and without stents. Stent placement induced no significant changes in the 3D streamline in the saccular model and slight changes in the blister-like model. Both saccular and blister-like models with stents had lower wall shear stress (WSS) and flow velocity, and higher oscillatory shear index, WSS gradient, and relative residence time than the equivalent models without stents, indicating the possibility that stent placement induced stagnant and disturbed blood flow. Cross-sectional vector velocity around the stent strut revealed complex blood flow patterns with variable direction and velocity. Although this study was a simulation under limited conditions, similar hemodynamic changes might be induced in the neck remnants treated with stent-assisted coil embolization.
authors.affiliation: Department of Neurosurgery, Mie University Graduate School of Medicine, Tsu, Mie, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Tanemura
authors.forename: Fujimaro
authors.initials: F
authors.lastname: Ishida
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Miura
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Umeda
authors.forename: Keiji
authors.initials: K
authors.lastname: Fukazawa
authors.forename: Hidenori
authors.initials: H
authors.lastname: Suzuki
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Sakaida
authors.forename: Satoshi
authors.initials: S
authors.lastname: Matsushima
authors.forename: Shinichi
authors.initials: S
authors.lastname: Shimosaka
authors.forename: Waro
authors.initials: W
authors.lastname: Taki
mesh_terms: D017130:Angioplasty; D001783:Blood Flow Velocity / Q000502:physiology; D002560:Cerebrovascular Circulation / Q000502:physiology*; D004621:Embolization, Therapeutic; D006801:Humans; D057446:Hydrodynamics; D002532:Intracranial Aneurysm / Q000503:physiopathology* / Q000628:therapy*; D008955:Models, Cardiovascular; D015607:Stents; D014655:Vascular Resistance / Q000502:physiology