Supplementary file 1_Presence of small and large branch vessels from intracranial aneurysms increases the risk of post-treatment recurrence and retreatment following endovascular coiling: insights from a propensity score-matched cohort.docx

ObjectiveAneurysms with involvement of a branch vessel within the sac represent a particularly challenging morphological feature in the context of coil embolization. The aim of this propensity score-matched cohort study was to determine the impact of branch vessel involvement on angiographic occlusion, clinical outcomes, recurrence, and retreatment after endovascular coiling.
MethodsWe conducted a single-center retrospective cohort study of intracranial aneurysms treated with conventional, balloon-assisted, or stent-assisted coiling. Propensity score matching was performed to reduce confounding. Packing density was computed using AngioSuite. Regression models were used to analyze immediate and final Raymond–Roy Occlusion Classification grade, recurrence, and retreatment in the matched cohort.
ResultsOut of 330 patients with 330 aneurysms, 39 aneurysms (11.8%) had branch involvement. Propensity score matching yielded 31 branch-involving aneurysms (BVAs) matched to 31 non-BVAs. Immediate Raymond-Roy grade (OR: 2.57, 95% CI: 0.96–7.13, p = 0.063) and packing density (mean difference −3.04%, 95% CI: −8.14–2.06, p = 0.247) did not differ significantly between groups. At follow-up, BVAs had worse final Raymond-Roy grade (OR: 6.33, 95% CI: 2.15–20.83, p = 0.0013) and lower odds of complete occlusion (OR: 0.085, 95% CI: 0.024–0.26, p < 0.001). Complete occlusion without recurrence was achieved in 20/30 (66.7%) non-BVAs compared to 6/30 (20.0%) BVAs during the follow-up period. Recurrence (OR: 5.55, 95% CI: 1.78–19.86, p = 0.005) and retreatment (OR: 4.44, 95% CI: 1.19–21.69, p = 0.034) were also higher in BVAs.
ConclusionBVAs exhibit significantly worse long-term angiographic outcomes with higher recurrence and retreatment rates. Branch vessel incorporation is an intrinsic risk factor for unfavorable angiographic durability post-coiling that warrants awareness and novel treatment strategies. Specifically, BVAs may warrant intensified imaging surveillance and consideration of neck-reconstruction strategies or primary clipping when branch vessel preservation is feasible.