title: Immediate and midterm outcomes of patients with cerebral aneurysms treated with Matrix1 and Matrix2 coils: a comparative analysis based on a single-center experience in 250 consecutive cases.
abstract: OBJECTIVE
  Recanalization after coil embolization of cerebral aneurysms remains a limitation of this progressively accepted modality. The Matrix detachable bioabsorbable coil (Boston Scientific Neurovascular, Natick, MA) was developed to overcome this limitation. We report a single-center experience using first- and second-generation Matrix coils.
  
  
  METHODS
  Immediate and midterm angiographic outcomes of 235 consecutive patients with 250 aneurysms treated with Matrix coils were reviewed retrospectively. The first 16 aneurysms included in the postmarket Acceleration of Connective Tissue Formation in Endovascular Aneurysm Repair (ACTIVE) study were treated exclusively with the Matrix coil, as per protocol. The next 234 aneurysms were treated in combination with bare platinum coils, stents, and the balloon-assisted technique. First-generation Matrix coils were used in 155 aneurysms (Matrix1 group) and second-generation Matrix coils were used in 79 aneurysms (Matrix2 group). Outcomes of the 3 groups were compared.
  
  
  RESULTS
  Immediate complete obliteration was achieved in 12.5% of the ACTIVE group aneurysms, 32.9% of the Matrix1 group, and 43.0% of the Matrix2 group. Overall, 87 (34.8%) aneurysms were completely occluded acutely. Procedure-related morbidity and mortality were 2.4 and 0%, respectively. Follow-up (median, 7.9 months) angiograms were obtained for 186 (74.4%) aneurysms. Complete obliteration of aneurysms was confirmed in 26.7% of the ACTIVE group, 53.4% of the Matrix1 group, and 64.2% of the Matrix2 group. Recanalization was observed in 33.3% of the ACTIVE group, 16.9% of the Matrix1 group, and 9.4% of the Matrix2 group. The overall recanalization rate was 16.1%.
  
  
  CONCLUSIONS
  Use of Matrix2 coils resulted in improved mechanical performance and anatomic outcome compared with Matrix1 coils. However, practitioners must be familiar with the mechanical characteristics of the Matrix coils, which are different from those of bare platinum coils.
authors.affiliation: Department of Neurosurgery, Kyoto University Graduate School of Medicine, Sakyo-ku, Kyoto, Japan. IshiiMD@gmail.com
authors.forename: Akira
authors.initials: A
authors.lastname: Ishii
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Murayama
authors.forename: Yih-Lin
authors.initials: YL
authors.lastname: Nien
authors.forename: Ichiro
authors.initials: I
authors.lastname: Yuki
authors.forename: P Henry
authors.initials: PH
authors.lastname: Adapon
authors.forename: Robert
authors.initials: R
authors.lastname: Kim
authors.forename: Reza
authors.initials: R
authors.lastname: Jahan
authors.forename: Gary
authors.initials: G
authors.lastname: Duckwiler
authors.forename: Fernando
authors.initials: F
authors.lastname: Viñuela
mesh_terms: D004621:Embolization, Therapeutic / Q000295:instrumentation* / Q000401:mortality*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005260:Female; D006801:Humans; D002532:Intracranial Aneurysm / Q000401:mortality* / Q000628:therapy*; D007564:Japan; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors; D016019:Survival Analysis; D015996:Survival Rate; D016896:Treatment Outcome