Introduction Materials, techniques, and treatment strategies used to coil ruptured intracranial aneurysms have evolved substantially. The present study provides a contemporary assessment of the safety and effectiveness of the HydroCoil Embolic System (HES) to treat ruptured cerebral aneurysms. Methods RAGE (Ruptured Aneurysms Treated with HydroGEl Coils) was a prospective, non-randomized, multicenter trial assessing the safety and effectiveness of coil embolization using HES in adult patients with ruptured, saccular intracranial aneurysms. The primary efficacy endpoint was adequate (complete occlusion or residual neck) angiographic occlusion at 18±6 months, without aneurysm rebleeding or retreatment secondary to recurrence. The primary safety endpoint, adjudicated independently, was a composite of procedure- or disease-related death within 30 days; major stroke within 30 days; and major ipsilateral stroke, neurological death, or aneurysm rebleeding within 18 months of treatment. The study hypothesized that hydrogel coils achieve adequate occlusion rates that are non-inferior to those of bare platinum coils. Adequate occlusion at 18±6 months was compared with a prespecified performance goal based on the published results of the bare platinum arm of the CLARITY study. Results A total of 771 subjects (average age 53.8±12.2 (range: 18–80) years, 72.2% (557/771) female) were included. Of the subjects in which occlusion assessment could be performed, 75.0% (405/540) achieved a successful primary efficacy outcome. The adequate occlusion rate at 18±6 months was 86.0% (455/529) and was superior to the prespecified performance goal of 80.4% (p=0.0004). Retreatment due to aneurysm recurrence was 13.2% (78/591) through 18 months. Any procedure- or disease-related death occurred in 2.6% (19/738) and any major stroke in 4.2% (31/731) of subjects within 30 days. The cumulative rates of neurological death and major ipsilateral stroke through 18 months were 2.8% (17/604) and 2.5% (15/593), respectively. The rebleed rate was 0.3% (2/724) within 30 days and 0.2% (1/588) between 31 days and 18 months. Overall, primary safety endpoint events occurred in 7.6% (47/619) of subjects. Conclusions HES coils are safe and effective for the management of ruptured intracranial aneurysms, achieving a superior rate of adequate occlusion when compared with a literature-based performance goal for bare platinum coils. Rates of target aneurysm rebleeding after HES coil embolization were very low.
Fiorella et al. (2026) studied this question.