Optimal Coil Packing Density for Aneurysmal Complete Obliteration in Flow Diversion Stenting: A Retrospective Study

Flow diverter stent (FDS) deployment with coil embolization (CE) achieves high aneurysmal occlusion rates. However, no established guidelines exist for the optimal packing density (PD) when treating large or giant aneurysms. This study aimed to investigate the optimal PD in FDS deployment with CE.

This retrospective multicenter study involved 97 consecutive patients with unruptured large or giant (≥ 10 mm) aneurysms treated with FDS deployment alone or with FDS and CE, between August 2019 and December 2023. We calculated the volume embolization ratio as the coil PD using Angiosuite Neuro Edition ver. 10.03. We defined O'Kelly-Marotta grading scale D as complete obliteration (CO) at 6 months after deployment and analyzed the associations between the PD and aneurysmal CO.

Seventeen patients (means ± SD age, 53.8±9.94 years; 14 [82.4%] female patients) in the FDS with CE group, and 18 patients (63.6±12.4 years; 14 [77.8%] female patients) in the FDS alone group were included for analysis. CO was achieved in 14 (82.3%) patients in the FDS with CE group and 9 (50.0%) in the FDS alone group (P = 0.08). volume embolization ratio (≥ 8.9%) was significantly associated with CO in the univariable analysis (P = 0.01; odds ratio: 14.3 [95% CI: 1.57-129.9]) and the multivariable analysis (P = 0.02; odds ratio, 10.5 [95% CI: 1.09-100.7]).

It may be unnecessary to continue CE after the PD has reached 8.9% volume embolization ratio when treating large or giant intracranial aneurysms with combined FDS and CE.