Long-Term Follow-up of Aneurysms Treated With Hydrogel-Coated Coils Shows Progressive Thrombosis and Improvement in Raymond-Roy Classification

Coil embolization of aneurysms has been shown to be a safe and effective method of aneurysm treatment. Hydrogel-coated coils were developed as a hybrid embolization device to increase the packing density of a coil mass in an aneurysm and to reduce retreatment and rerupture rates. Previous studies have shown a benefit compared with bare metal coils.

To present long-term follow-up of a cohort of patients treated with hydrogel-coated coils to better determine the effectiveness compared with bare platinum coils.

Between January 2003 and April 2012, we identified patients with both ruptured and unruptured aneurysms coiled at our institution, using some portion of hydrogel-coated coils. Planned follow-up angiography was performed at 6 months, 18 months, and 5 years post-treatment. All imaging was independently adjudicated by a single physician at a separate institution. The results were scored with the modified Raymond-Roy Occlusion Classification.

A total of 145 patients with 153 treated aneurysms were included in the study analysis. Immediately after treatment, 49% of aneurysms were classified at Raymond-Roy Occlusion Classification I or II, which improved to 83% by 6 months. This percent plateaued at 18-month and 5-year follow-up, measuring 86% and 90%, respectively. The retreatment rate was 14% over the 5-year period, and there were no rerupture events captured.

Treatment of intracranial aneurysms with coil embolization using hydrogel-coated aneurysms shows evidence of progressive occlusion, particularly over the first 6 months of follow-up. The retreatment rate is comparable with historical data, and the rerupture rate is low.