Incidence and Outcomes of Flow Diverter Braid Deformation following Treatment with Non-DFT Wire Devices

Flow diverter braid deformation is occasionally observed after flow diverter placement. However, the frequency and clinical significance of flow diverter braid deformation in non-drawn filled tube wire devices remain unclear. This retrospective, single-center study analyzed 139 consecutive patients (median age, 60 years; 82.7% women) who underwent flow diverter placement for intracranial aneurysms between 2017 and 2024. Follow-up angiography and cone-beam computed tomography images were compared with those obtained immediately after flow diverter deployment to identify flow diverter-related morphologic changes. The identified morphologic changes were classified into 4 major patterns (fish mouthing, bump, collapse, and shortening) as flow diverter braid deformation and 2 variants (distal tapering and edge flare) as minor morphologic changes. Cases with fish mouthing or collapse were classified as a high-risk flow diverter braid deformation category because of their association with thromboembolic complications. Flow diverter-related morphologic changes were detected in 31 patients (22.3%), including flow diverter braid deformation in 24 patients (17.3%), at the first angiographic follow-up, and no progression was detected during subsequent observations. The most common pattern was shortening (12.9%), followed by distal tapering (5.0%), and high-risk flow diverter braid deformation was rare (fish mouthing, 1.4%; collapse, 1.4%). Neointimal hyperplasia was more frequent in the flow diverter braid deformation group, whereas the rates of in-stent stenosis, aneurysm occlusion (O'Kelly-Marotta grades C-D), retreatment, and favorable functional outcomes (modified Rankin Scale, 0-2) did not differ significantly between the groups. Younger age and proximal stent oversizing were independent predictors of flow diverter braid deformation. Given the rarity of the high-risk category and the absence of adverse outcomes, flow diverter braid deformation represents a benign and stable morphological change in non-drawn filled tube wire flow diverters.