title: Follow-up of cerebral aneurysm embolization with hydrogel embolic system: Systematic review and meta-analysis.
abstract: BACKGROUND
  Hydrogel embolic system (HES) for endovascular treatment of cerebral aneurysms was developed to reduce the risk of aneurysm recurrence and the rate of retreatment. The aim of this systematic review was to verify the efficacy of HES, also in comparison to bare platinum coils (BPC).
  
  
  METHODS
  A systematic literature search was performed by two independent reviewers for articles published until January 31st, 2013 on the follow-up recurrence rate of intracranial aneurysm embolization with hydrogel-coated coils.
  
  
  RESULTS
  Thirteen articles on the use of HES for embolization of cerebral aneurysms were included in this study, for a total of 1683 embolized aneurysms. Significant heterogeneity was found regarding patient populations, methods of aneurysm coiling, follow-up schedules, and recurrence definitions. The pooled rate of initial complete aneurysm occlusion was 55% (95%CI, 38-70%); 59% (95%CI, 43-74%) in the subgroup of aneurysms treated with the use of HES. The pooled total recurrence rate was 19% (95%CI, 15-24%); 17% (95%CI, 14-22%) in the HES-treated subgroup. The pooled major recurrence rate was 12% (95%CI, 8-18%); 11% (95%CI, 7-16%) in the HES-treated subgroup. Comparing both types of coils, the pooled odds ratio for total recurrence was 0.63 (95%CI, 0.45-0.88; p=0.008) in favor of HES.
  
  
  CONCLUSIONS
  Embolization of cerebral aneurysms using HES seems to result in a lower rate of recurrence than that obtained using BPC, which is in line with the only randomized controlled trial. High-quality prospective studies are needed to define specific indications for the use of hydrogel-coated coils.
authors.affiliation: Department of Radiology and Diagnostic Imaging, Nicolaus Copernicus University, Collegium Medicum, Bydgoszcz, Poland. Electronic address: serafin@cm.umk.pl.
authors.forename: Zbigniew
authors.initials: Z
authors.lastname: Serafin
authors.affiliation: Unit of Radiology, IRCCS Policlinico San Donato, Via Morandi 30, 20097 San Donato Milanese, Italy. Electronic address: gianni.dileo77@gmail.com.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Di Leo
authors.affiliation: Department of Radiology and Diagnostic Imaging, Nicolaus Copernicus University, Collegium Medicum, Bydgoszcz, Poland. Electronic address: alicja.palys@gmail.com.
authors.forename: Alicja
authors.initials: A
authors.lastname: Pałys
authors.affiliation: Department of Neurology, Nicolaus Copernicus University, Collegium Medicum, Bydgoszcz, Poland. Electronic address: magy_mat@by.onet.pl.
authors.forename: Magdalena
authors.initials: M
authors.lastname: Nowaczewska
authors.affiliation: Department of Neurosurgery and Neurotraumatology, Nicolaus Copernicus University, Collegium Medicum, Bydgoszcz, Poland. Electronic address: beuthw@wp.pl.
authors.forename: Wojciech
authors.initials: W
authors.lastname: Beuth
authors.affiliation: Unit of Radiology, IRCCS Policlinico San Donato, Via Morandi 30, 20097 San Donato Milanese, Italy; Dipartimento di Scienze Biomediche per la Salute, Università degli Studi di Milano, Via Morandi 30, 20097 San Donato Milanese, Italy. Electronic address: Francesco.sardanelli@unimi.it.
authors.forename: Francesco
authors.initials: F
authors.lastname: Sardanelli
mesh_terms: D020099:Coated Materials, Biocompatible / Q000737:chemistry*; D004621:Embolization, Therapeutic / Q000295:instrumentation*; D004867:Equipment Design; D005500:Follow-Up Studies; D006801:Humans; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate / Q000737:chemistry*; D002532:Intracranial Aneurysm / Q000628:therapy*; D010984:Platinum / Q000737:chemistry; D012008:Recurrence; D019233:Retreatment; D016896:Treatment Outcome
chemical_list: D020099:Coated Materials, Biocompatible; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D010984:Platinum
keywords: Hydrogel embolic system (HES); Intracranial aneurysm; Meta-analysis; Systematic review; Therapeutic embolization