Hydrogel-coated coils versus bare platinum coils for the endovascular treatment of intracranial aneurysms (HELPS): a randomised controlled trial

Lancet. 2011 May 14;377(9778):1655-62. doi: 10.1016/S0140-6736(11)60408-X.

Abstract

Background: Coated coils for endovascular treatment of cerebral aneurysm were developed to reduce recurrence and retreatment rates, and have been in clinical use for 8-9 years without robust evidence to determine their efficacy. We assessed the efficacy and safety of hydrogel-coated coils.

Methods: This randomised trial was undertaken in 24 centres in seven countries. Patients aged 18-75 years with a previously untreated ruptured or unruptured cerebral aneurysm of 2-25 mm in maximum diameter were randomly allocated (1:1) to aneurysm coiling with either hydrogel-coated coils or standard bare platinum coils (control). Randomisation was done with a computer-generated sequence, stratified by aneurysm size, shape, and dome-to-neck ratio; intention to use assist device; and by region. Participants and those assessing outcomes were masked to allocation. Analysis was by modified intention to treat (excluding missing data). Primary outcome was a composite of angiographic and clinical outcomes at 18-month follow-up. We also did prespecified subgroup analyses of characteristics likely to be relevant to angiographic outcome. This study is registered as an International Standard Randomised Controlled Trial, number ISRCTN30531382.

Findings: 249 patients were allocated to the hydrogel coil group and 250 to the control group. In 44 of 467 patients for whom an 18-month composite primary outcome was unavailable, 6-month angiographic results were used. 70 (28%) patients in the hydrogel group and 90 (36%) control patients had an adverse composite primary outcome, giving an absolute reduction in the proportion of adverse composite primary outcomes with hydrogel of 7·0% (95% CI -1·6 to 15·5), odds ratio (OR) 0·73 (0·49-1·1, p=0·13). In a prespecified subgroup analysis in recently ruptured aneurysms, there were more adverse composite primary outcomes in the control group than in the hydrogel group-OR 2·08 (1·24-3·46, p=0·014). There were 8·6% fewer major angiographic recurrences in patients allocated to hydrogel coils-OR 0·7 (0·4-1·0, p=0·049). There were five cases of unexplained hydrocephalus in not-recently-ruptured aneurysms in the hydrogel coil group and one case in the control group.

Interpretation: Whether use of hydrogel coils reduces late aneurysm rupture or improves long-term clinical outcome is not clear, but our results indicate that their use lowers major recurrence.

Funding: MicroVention Inc.

Publication types

  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aneurysm, Ruptured / diagnostic imaging
  • Aneurysm, Ruptured / therapy*
  • Cerebral Angiography
  • Coated Materials, Biocompatible*
  • Embolization, Therapeutic / adverse effects
  • Embolization, Therapeutic / methods*
  • Female
  • Humans
  • Hydrocephalus / etiology*
  • Hydrogel, Polyethylene Glycol Dimethacrylate* / adverse effects
  • International Cooperation
  • Intracranial Aneurysm / diagnostic imaging
  • Intracranial Aneurysm / therapy*
  • Male
  • Middle Aged
  • Odds Ratio
  • Platinum*
  • Retreatment
  • Secondary Prevention
  • Time Factors
  • Treatment Outcome

Substances

  • Coated Materials, Biocompatible
  • Hydrogel, Polyethylene Glycol Dimethacrylate
  • Platinum

Associated data

  • ISRCTN/ISRCTN30531382