Feasibility of vault configuration of the Neuroform Atlas stent in the treatment of bifurcation intracranial aneurysm: clinical observation and hemodynamic simulation

Background: Coil prolapse and stent-induced vascular deformation during single stent-assisted coiling (SSAC) of bifurcation intracranial aneurysms (BIAs) may compromise branch vessel patency. The vault configuration achieved via the Neuroform Atlas stent (NAS) is a clinically observed deployment pattern that may contribute to aneurysm neck coverage while maintaining branch vessel patency; however, its morphological and hemodynamic characteristics remain insufficiently characterized. This study aimed to provide a preliminary quantitative description of vault configuration.

Methods: This retrospective study included 35 BIAs treated with single NAS-assisted coiling. Vascular morphological characteristics were evaluated via digital subtraction angiography (DSA) at pretreatment, posttreatment, and follow-up time points. In addition, patient-specific virtual stenting and computational fluid dynamics (CFD) simulations were performed in six cases (with seven protected branch vessels) for quantitative characterization of the branch-protective efficacy conferred by the vault.

Results: All branch vessels protected by the vault configuration remained patent during follow-up. No significant differences were observed in vessel diameters or vascular angles across pretreatment, posttreatment, or follow-up imaging (all P values >0.05). Hemodynamic analysis showed that branch-flow responses varied across anatomical configurations. In exploratory simulations, six of seven simulated branches demonstrated smaller flow reductions in the vault models than in the corresponding no-vault models, with a mean branch-flow reduction 5.12% lower than that observed in the no-vault models; however, the magnitude of the differences varied considerably across cases.

Conclusions: The vault configuration of the Neuroform Atlas appears to be a technically feasible deployment pattern in selected cases and was associated with preserved branch-vessel patency in this cohort. Virtual deployment and CFD analyses suggested that vault-associated flow alterations may vary according to local vascular anatomy. However, the observed hemodynamic findings should be considered exploratory and hypothesis-generating, and further validation in larger cohorts is needed.