Hemodynamic Changes by Flow Diverters in Rabbit Aneurysm Models

Abstract

Background and Purpose-The effect of flow diverter (FD) on hemodynamic changes observed in aneurysms is inevitably affected by the actual structural configuration of deployed FD. We studied the resultant hemodynamic changes after implantation of FDs using computational fluid dynamic simulations based on micro-computed tomography reconstructions in rabbit aneurysm model. Methods-The FDs by micro-computed tomography images and vascular model based on rabbit-specific angiograms in 14 rabbits were reconstructed for computational fluid dynamic studies, and rabbit-specific inlet flow waveforms were used as boundary conditions. The occluded group (n=10) and unoccluded group (n=4) were divided according to the follow-up angiography. Hemodynamic parameters were separately evaluated for significance with respect to FD implantation and healing. Results-The normalized mean wall shear stress of the aneurysm sac and inflow volume were significantly reduced after FD deployment, and the relative residence time was significantly increased after treatment, without significant differences in mean pressure of aneurysm sac. When compared with the unoccluded group, the average relative residence time increment and percentage of inflow volume reduction in occluded group were higher. Additionally, the inlet of stream after FD deployment in the occluded group was more prevalent near the central region of the neck, whereas in the unoccluded group, it was more likely to occur near the proximal part of the neck. Conclusions-This

Flow diversion of tandem cerebral aneurysms: a multi-institutional retrospective study

“…Impeding aneurysm inflow by flow diversion not only promotes aneurysm occlusion but also promotes repair of the parent artery to a more physiological state. 10,30 Importantly, small branching feeders off the parent artery appear to remain intact even when covered by telescoping flow diverters, making these diverters especially useful when treating tandem aneurysms separated by a longer distance. 4,11,14,26,30 We successfully deployed 25 PEDs to treat 38 tandem aneurysms in 17 patients.…”

Hemodynamics of Flow Diverters

“…Aggregating the results from about 20 flow studies on idealized, in vivo, and patient geometries (87 patient cases, half of which are from two studies [10,11]) suggests a spectrum of flow diversion response. Flow diversion reduces the intraneurysmal flow activity in idealized/simplified sidewall-type geometries by about 75-95% [7,[17][18][19][20], by about 20-40% in simplified bifurcation-type geometries [17,21], and by around 60% in an in vivo aneurysm model [22,23]. Reduction in the intraneurysmal flow activity in clinical cases runs the entire gamut from around 20-30% in bifurcation geometries to around 80-90% in sidewall geometries with an average reduction of around 50-60% [9][10][11][24][25][26][27][28][29][30][31].…”

Successful Retreatment of Recurrent Intracranial Vertebral Artery Dissecting Aneurysms After Stent-Assisted Coil Embolization: A Self-Controlled Hemodynamic Analysis

“…With development of CFD techniques, more and more researchers estimated the hemodynamic effect of intracranial stent or coils using different modeling techniques. 17, 19, 22-27 However, the simulation results may be influenced by methodological diversity. In the study by Tremmel et al, 26 the stent was conformed to fit into parent vessel and deployed across aneurysm neck, which was thought to be less accurate in simulations compared with real status of stent deployment.…”

“…In the study by Tremmel et al, 26 the stent was conformed to fit into parent vessel and deployed across aneurysm neck, which was thought to be less accurate in simulations compared with real status of stent deployment. Some other studies evaluated hemodynamic alterations by stent placement in animal models and the stent geometry was reconstructed using micro-CT. 22, 27 Such stent model was much more accurate, however, it was less likely to apply to large cohort study. Used in our present study, the virtual stenting technique might be a better option for CFD simulation of aneurysm outcome after SACE.…”