Repeated recurrence after endovascular treatment for cerebral aneurysms: predictive clinical factors and optimal therapeutic management.

Despite significant advances in endovascular treatment (EVT) of cerebral aneurysms, post-treatment recurrence necessitating multiple retreatments remains a severe concern. Herein, we investigated the clinical characteristics of aneurysms necessitating multiple retreatments after EVT (refractory aneurysms: R-ANs) and explored appropriate management strategies. This retrospective cohort study enrolled 1,045 aneurysms initially treated with EVT between 2016 and 2022. R-ANs were defined as cases requiring two or more retreatment sessions due to repeated recurrence or regrowth. Clinical data were retrospectively reviewed, and predictive factors were identified. Furthermore, the treatments performed and clinical outcomes were investigated. Of 1,045 aneurysms, 101 (9.7%) exhibited recurrence or regrowth requiring retreatment. Among these, 23 aneurysms (2.2%) requiring two or more retreatment sessions, which were classified as R-ANs. As for the predictive factors of R-AN development, large size (> 10 mm), and circumferential aneurysmal wall enhancement on vessel wall imaging (VWI) were identified as relevant and independent predictive factors, with odds ratios of 3.92 (95% CI, 1.36- 11.62), 8.02 (95% CI, 2.02- 53.6), respectively. In terms of therapeutic outcomes, repeat EVT sessions provided favorable long-term clinical outcomes (aneurysm stabilization, 85.0%; favorable occlusion, 65.0%) and low periprocedural complication rates (2.6%). This study identified the relevant predictive factors for R-AN development, suggesting that careful follow-up is essential in patients with these factors. Furthermore, repeated EVT sessions appears to be a safe and efficient treatment strategy for such challenging cases.