title: HydroCoils reduce recurrence rates in recently ruptured medium-sized intracranial aneurysms: a subgroup analysis of the HELPS trial.
abstract: OBJECTIVE
  The HydroCoil Endovascular Aneurysm Occlusion and Packing Study (HELPS) was a randomized, controlled trial comparing HydroCoils with bare-platinum coils. The purpose of this study was to perform a subgroup analysis of angiographic and clinical outcomes of medium-sized aneurysms in the HELPS trial.
  
  
  METHODS
  Patients with medium-sized aneurysms (5-9.9 mm) were selected from the HELPS trial. Outcomes compared between the HydroCoil and bare-platinum groups included the following: 1) any recurrence, 2) major recurrence, 3) retreatment, and 4) mRS score of ≤2. Subgroup analysis by rupture status was performed. Multivariate logistic regression analysis adjusting for aneurysm neck size, shape, use of adjunctive device, and rupture status was performed.
  
  
  RESULTS
  Two hundred eighty-eight patients with medium-sized aneurysms were randomized (144 in each group). At 15-18 months posttreatment, the major recurrence rate was significantly lower in the HydroCoil group than in controls (18.6% versus 30.8%, P = .03, respectively). For patients with recently ruptured aneurysms, the major recurrence rate was significantly lower for the HydroCoil group than for controls (20.3% versus 47.5%, P = .003), while rates were similar between groups for unruptured aneurysms (16.7% versus 14.8%, P = .80). Multivariate analysis of patients with recently ruptured aneurysms demonstrated a lower odds of major recurrence with HydroCoils (OR = 0.27; 95% CI, 0.12-0.58; P = .0007). No difference in retreatment rates or mRS of ≤2 was seen between groups.
  
  
  CONCLUSIONS
  HydroCoils were associated with statistically significant and clinically relevant lower rates of major recurrence for recently ruptured, medium-sized aneurysms in the HELPS trial. Because this was not a prespecified subgroup analysis, these results should not alter clinical practice but, rather, provide insight into the design of future clinical trials comparing bare platinum with second-generation coils.
authors.affiliation: From the Department of Radiology (W.B., H.J.C., D.F.K.), Mayo Clinic, Rochester, Minnesota brinjikji.waleed@mayo.edu.
authors.forename: W
authors.initials: W
authors.lastname: Brinjikji
authors.affiliation: Institute for Ageing and Health (P.M.W.), Newcastle University, Newcastle-upon-Tyne, United Kingdom.
authors.forename: P M
authors.initials: PM
authors.lastname: White
authors.affiliation: Department of Clinical Neuroscience (H.N.), University of Edinburgh, Edinburgh, United Kingdom.
authors.forename: H
authors.initials: H
authors.lastname: Nahser
authors.affiliation: Walton Centre (J.W., R.S.), Liverpool, United Kingdom.
authors.forename: J
authors.initials: J
authors.lastname: Wardlaw
authors.affiliation: Walton Centre (J.W., R.S.), Liverpool, United Kingdom.
authors.forename: R
authors.initials: R
authors.lastname: Sellar
authors.affiliation: From the Department of Radiology (W.B., H.J.C., D.F.K.), Mayo Clinic, Rochester, Minnesota.
authors.forename: H J
authors.initials: HJ
authors.lastname: Cloft
authors.affiliation: From the Department of Radiology (W.B., H.J.C., D.F.K.), Mayo Clinic, Rochester, Minnesota.
authors.forename: D F
authors.initials: DF
authors.lastname: Kallmes
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D017542:Aneurysm, Ruptured / Q000628:therapy*; D004621:Embolization, Therapeutic / Q000295:instrumentation* / Q000379:methods; D004867:Equipment Design; D005260:Female; D006801:Humans; D020100:Hydrogels; D002532:Intracranial Aneurysm / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D010984:Platinum; D012008:Recurrence; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D020100:Hydrogels; D010984:Platinum