@article {Narata, author = {A.P. Narata and F.S. de Moura and I. Larrabide and C.M. Perrault and F. Patat and R. Bibi and S. Velasco and A.-C. Januel and C. Cognard and R. Chapot and A. Bouakaz and C.A. Sennoga and A. Marzo}, title = {The Role of Hemodynamics in Intracranial Bifurcation Arteries after Aneurysm Treatment with Flow-Diverter Stents}, year = {2018}, doi = {10.3174/ajnr.A5471}, publisher = {American Journal of Neuroradiology}, abstract = {BACKGROUND AND PURPOSE: Treatment of intracranial bifurcation aneurysms with flow-diverter stents can lead to caliber changes of the distal vessels in a subacute phase. This study aims to evaluate whether local anatomy and flow disruption induced by flow-diverter stents are associated with vessel caliber changes in intracranial bifurcations.MATERIALS AND METHODS: Radiologic images and demographic data were acquired for 25 patients with bifurcation aneurysms treated with flow-diverter stents. Whisker plots and Mann-Whitney rank sum tests were used to evaluate if anatomic data and caliber changes could be linked. Symmetry/asymmetry were defined as diameter ratio 1 = symmetric and diameter ratio \<1 = asymmetric. Computational fluid dynamics was performed on idealized and patient-specific anatomies to evaluate flow changes induced by flow-diverter stents in the jailed vessel.RESULTS: Statistical analysis identified a marked correspondence between asymmetric bifurcation and caliber change. Symmetry ratios were lower for cases showing narrowing or subacute occlusion (medium daughter vessel diameter ratio = 0.59) compared with cases with posttreatment caliber conservation (medium daughter vessel diameter ratio = 0.95). Computational fluid dynamics analysis in idealized and patient-specific anatomies showed that wall shear stress in the jailed vessel was more affected when flow-diverter stents were deployed in asymmetric bifurcations (diameter ratio \<0.65) and less affected when deployed in symmetric anatomies (diameter ratio \~{}1.00).CONCLUSIONS: Anatomic data analysis showed statistically significant correspondence between caliber changes and bifurcation asymmetry characterized by diameter ratio \<0.7 (P \< .001). Similarly, computational fluid dynamics results showed the highest impact on hemodynamics when flow-diverter stents are deployed in asymmetric bifurcations (diameter ratio \<0.65) with noticeable changes on wall sheer stress fields. Further research and clinical validation are necessary to identify all elements involved in vessel caliber changes after flow-diverter stent procedures.DRdaughter vessel diameter ratioFDSflow-diverter stentWSSwall shear stress}, issn = {0195-6108}, URL = {https://www.ajnr.org/content/early/2017/11/23/ajnr.A5471}, eprint = {https://www.ajnr.org/content/early/2017/11/23/ajnr.A5471.full.pdf}, journal = {American Journal of Neuroradiology} }