HydroCoils Effective in Recently Ruptured, Medium-Sized Aneurysm

NASHVILLE — Compared with bare platinum coils, HydroCoils yielded a significantly lower rate of major recurrence of recently ruptured, medium-sized aneurysms, according to data presented at the International Stroke Conference 2015.

“For future trials examining modified coils compared with bare platinum coils, focusing on this subset of patients may be helpful to prove the benefit of these newer technologies,” Waleed Brinjikji, MD, study researcher from the Mayo Clinic in Rochester, Minn., told Neurology Advisor.

The study was a subgroup analysis of the randomized controlled HydroCoil Endovascular Aneurysm Occlusion and Packing Study (HELPS).

According to Brinjikji, the HELPS trial was unable to show any difference between the HydroCoil and bare platinum coils in a composite of angiographic and clinical outcomes, but did demonstrate that patients with recently ruptured aneurysms treated with bare platinum coils had a higher rate of adverse clinical outcome in the bare platinum coil group. “In addition, there was a treatment effect in the medium-sized aneurysm group, but it didn’t quite reach statistical significance,” he said.

This led Brinjikji and colleagues to conduct the HELPS subanalysis, which looked at HydroCoils vs. bare platinum coils in patients with medium-sized aneurysms (5-9.9 mm). Primary outcomes were any recurrence, major recurrence, retreatment, and good neurological outcome (defined as modified Rankin Scale ≤2).

Researchers performed a separate analysis of outcomes involving recently ruptured and non-recently ruptured aneurysms. Overall, 288 patients with medium-sized aneurysms were randomly assigned to receive either HydroCoils or bare platinum coils (144 in each group).

Fifteen to 18 months after treatment, rate of major recurrence was reduced in the HydroCoil group (18.6% vs. 30.8%; P=.03).

In the recently ruptured aneurysm cohort, rate of major recurrence was lower for patients who received the HydroCoil (20.3% vs. 47.5%; P=.003), whereas it did not significantly differ among patients with unruptured aneurysms (P=.80).

Among patients with recently ruptured aneurysms, multivariate analysis indicated that the HydroCoil lowered risk for any recurrence (OR=0.37; 95% CI, 0.18-0.76; P=.006) and major recurrence (OR=0.27; 95% CI, 0.12-0.58; P=.0007) compared with the bare platinum coil. Also with the HydroCoil, there was a trend suggesting lower retreatment rates in the recently ruptured aneurysm group (OR=0.00, 95%CI, 0.00-2.01; P=.12).

Brinjikji explained what he believes are the reasons for the observed differences between medium-sized vs. large- and small-sized aneurysms.

“Small aneurysms have excellent outcomes with coiling no matter how you treat them,” he said. “In coiling large aneurysms, literature indicates that no matter what you do, they have high rates of recanalization. So, the sweet spot for proving the benefit of newer technologies is this group of medium-sized aneurysms.”

For more coverage of the International Stroke Conference 2015, go here.


  1. Brinjikji  W et al. Abstract 112. Presented at: International Stroke Conference 2015; Feb. 11-13, 2015; Nashville, Tennessee.