Delayed aneurysm occlusion after single stent-assisted coiling: factors in initially incompletely occluded unruptured intracranial aneurysms.

Single stent-assisted coiling (sSAC) is used to treat saccular unruptured intracranial aneurysms (sUIAs), but factors influencing delayed complete occlusion (CO) remain incompletely understood. We retrospectively analyzed 260 patients with sUIAs treated with sSAC. Immediate CO was assessed angiographically post-procedure, and delayed CO was defined as progression to CO during follow-up in initially incompletely occluded aneurysms. Clinical and morphological variables were evaluated using univariate and multivariate logistic regression to identify factors. Immediate CO was achieved in 38.1% of patients. An aspect ratio ≥ 1.1 was positively associated with immediate CO (adjusted OR, 2.01; 95% CI, 1.09-3.71; P = 0.02), while hyperlipidemia was negatively associated (adjusted OR, 0.47; 95% CI, 0.26-0.88; P = 0.02). Among 161 patients without immediate CO, 81.4% achieved delayed CO during a median follow-up of 491 days. Aneurysms with a wide neck (> 4 mm or dome-to-neck ratio < 1.5) or a size ratio (maximum aneurysm size / parent artery diameter) ≥ 2.3 were less likely to achieve delayed CO (adjusted ORs, 0.35 [95% CI, 0.13-0.94] and 0.34 [95% CI, 0.12-0.93], respectively; both P = 0.04). Clinical outcomes were favorable overall, with 98.8% of patients achieving a 90-day modified Rankin Scale score of 0-2 with a low complication rate of 5.8%. While most sUIAs without immediate CO progress to occlusion over time, specific morphological and clinical factors may influence this outcome. Identifying these predictors can support patient selection, procedural decision-making, and follow-up planning to optimize long-term results after sSAC for sUIAs.