# Comparison of second-generation hydrogel embolic coils and bare platinum coils in ruptured intracranial aneurysm treatment: A prospective, multicenter, randomized controlled study

## TL;DR

This study compares second-generation hydrogel embolic coils and bare platinum coils for treating ruptured brain aneurysms, finding no significant difference in recurrence rates.

## Contribution

A prospective, multicenter, randomized controlled trial comparing second-generation hydrogel embolic coils and bare platinum coils in ruptured intracranial aneurysm treatment.

## Key findings

- No significant difference in aneurysm recurrence rates between hydrogel embolic coils and bare platinum coils.
- Hydrogel embolic coils showed better ease of manipulation compared to bare platinum coils.
- No significant differences in retreatment rates, clinical outcomes, or shunt operations between the two coil types.

## Abstract

To reduce the recurrence of cerebral aneurysms, second-generation hydrogel embolic coils (HECs) have been developed. We aimed to compare the impacts of bare platinum coils (BPCs) and HECs on the recurrence of ruptured intracranial aneurysms (RIAs). In this study, participants with an RIA were randomly assigned to the BPC or HEC group at a 1:1 ratio. The primary outcome was any recurrence during the 12-month follow-up period. The secondary outcomes included retreatment, procedural complications, delayed cerebral ischemia, favorable clinical outcomes (modified Rankin Scale score ≤ 2), ventriculoperitoneal shunt operation, and the coil’s ease of manipulation. After excluding 11 patients, 57 patients were ultimately included for analysis (BPC, n = 26; HEC, n = 31). The primary outcome was not statistically significant between 2 groups (BPC group: 10/26 [38.5%]; HEC group: 6/31 [19.4%]; P = 0.144). The secondary outcomes did not differ between the 2 groups, except for the coil’s ease of manipulation (P = 0.007). Multivariate analysis revealed no significant difference between the two groups in terms of the primary outcome (rate of recurrence [OR = 0.46; 95% CI, 0.13–1.61; P = 0.223]) or in terms of the secondary outcomes, including retreatment (OR = 0.77; 95% CI, 0.12-5.00; P = 0.766), favorable clinical outcomes (OR = 1.05; 95% CI, 0.16–6.90; P = 0.957), or VP shunt operation (OR = 0.11; 95% CI, 0.01–1.54; P = 0.102). Among patients who underwent coil embolization for an RIA, there were no significant differences between the two groups in terms of the rates of recurrence, retreatment, favorable clinical outcomes or VP shunt operation during the 12-month follow-up period. Given the small sample size, these results should be interpreted with caution. This study is a registered clinical trial. It was prospectively registered in the ClinicalTrials.gov (NCT04988503) on July 23, 2021.

The online version contains supplementary material available at 10.1007/s10143-026-04212-1.