Hemodynamic Characteristics and Clinical Outcome for Intracranial Aneurysms Treated with the Derivo Embolization Device, a Novel Second-Generation Flow Diverter

BACKGROUND: We investigated the relationship between hemodynamic characteristics and clinical outcomes for aneurysms treated by the Derivo embolization device, a novel second-generation flow-diverter stent, using computational fluid dynamics (CFD). METHODS: Data were retrospectively obtained from 2 centers between 2017 and 2019. During the period, 23 patients were treated for 23 aneurysms with the Derivo embolization device. In 17 patients we were able to conduct CFD analysis as 6 were excluded due to precoiling, unsuitable arterial geometry, and complex geometric form. Aneurysm occlusion was rated with the O'Kelly-Marotta grading scale on digital subtraction angiography 6 months after stent placement in all patients. Hemodynamic and morphologic parameters were statistically compared between 2 groups: with full occlusion and with a remnant. RESULTS: Full occlusion was observed in 17 of 23 (73.9%) patients. In the group suitable for CFD analysis, we observed 13 fully occluded aneurysms and 4 with any remnant (specifically 1 O'Kelly-Marotta C, 1 B, and 2 A). The energy loss per volume, which indicates the energy loss through the aneurysm, was significantly larger in prestenting and post stenting (P < 0.05) in the complete occlusion cases. In addition, the inflow concentration index and inflow area ratio of the remnant cases were significantly larger and lower, respectively (P < 0.05). CONCLUSIONS: Our CFD results indicate that the energy loss involved with the blood flow passing through an aneurysm and concentrated inflow into an aneurysm were the most important factors to determine whether an aneurysm will become a complete occlusion or remnant case.