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La compétition de flux comme facteur prédictif de la perméabilité des branches artérielles collatérales après mise en place des stents de diversion de flux dans les artères intracrâniennes

Abstract : The outcome of jailing arterial branches that emerge near intracranial aneurysms during flow-diverting stent deployment remains controversial. We report an animal research study aiming to elucidate the role of collateral supply in the hemodynamic changes and neointimal modifications resulting from jailing arteries with flow-diverting stents. To serve this purpose, we sought to quantify the hemodynamic changes at the jailed arterial branches immediately after stenting, as well as quantify the ostia surface values at three months post-stenting, in the presence or absence of collateral arterial flow. Methods After a priori power analysis, two groups (A, B), each containing seven large white swine, were created according to an animal flow model for terminal and anastomotic arterial circulation. Group A corresponded to an arterial configuration with anastomotic type of arterial supply for the territory of the right Ascending Pharyngeal artery (APhA) and group B to an arterial configuration of terminal type of arterial supply for the territory of the right APhA. Subsequently, all animals were stented by flow-diverting stents, jailing the right ascending pharyngeal arteries. Mean flow rates and velocities inside the jailed branches were quantified before and after stenting by time-resolved, 3D, phase contrast MRA. After three months the jailed ostia surface values were quantified on scanning electron microscopic images. The data were analyzed using descriptive statistics and group comparisons with parametric and non-parametric tests.Results Endovascular procedures were feasible, without in situ thrombus formation or ischemic DWI findings on post-procedure MRIs. Immediately following stenting, mean flow rate values at the jailed right ascending pharyngeal arteries were reduced in group A, as compared to the pre-stenting values [P = 0.0008, power: 0.9548]. In contrast, mean flow rates for group B remained similar to the pre-stenting values. At three months post-stenting, mean ostia surface values were significantly higher for group B (527,911 ± 306,229 μm2) than for group A (89,329 ± 59,762 μm2) [P< 0.01, power: 1.00], even though the initial dimensions of the jailed ostia were similar between groups. A statistically significant correlation was found between group (A or B), mean flow rates post-stenting and ostia surface values at three months. ConclusionWhen important collateral supply was present, jailing side arteries with flow-diverters resulted in an immediate, significant reduction in flow rate inside these arteries, as compared to the pre-stenting values. In contrast, when competitive flow was absent, jailing did not result in significant flow rate reductions inside the jailed arteries. Ostium surface values at three months were significantly higher in the terminal group of jailed arteries, compared to the anastomotic group and strongly correlated with the velocity value reductions post- stenting. Key words: flow-diverting stent, collateral arteries, endothelialization, ostium, embolization, magnetic resonance angiography, magnetic resonance imaging
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Christina Iosif. La compétition de flux comme facteur prédictif de la perméabilité des branches artérielles collatérales après mise en place des stents de diversion de flux dans les artères intracrâniennes. Médecine humaine et pathologie. Université de Limoges, 2016. Français. ⟨NNT : 2016LIMO0002⟩. ⟨tel-01462821⟩

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