title: Matrix and bioabsorbable polymeric coils accelerate healing of intracranial aneurysms: long-term experimental study.
abstract: OBJECTIVE
  Acceleration of intra-aneurysmal clot organization and fibrosis may be a solution to preventing aneurysm recanalization after endovascular treatment. The purpose of this study was to evaluate the short-term efficacy and long-term safety of the new Matrix coil system.
  
  
  METHODS
  Matrix coils consist of thin platinum coils covered with a bioabsorbable, polymeric material (polyglycolic acid/lactide). Fifty-two experimental aneurysms were created in 26 swine. All of the aneurysms were tightly packed with Matrix or Guglielmi detachable coils (GDC). Comparative angiographic and histopathologic data were analyzed at 2 weeks (n=14), 3 months (n=6), and 6 months (n=6) after embolization.
  
  
  RESULTS
  Three aneurysms treated with GDC ruptured despite tight packing. No recanalization or rupturing was observed in the aneurysms embolized with Matrix coils. At 14 days after embolization, the aneurysms treated with Matrix coils exhibited a more extensive area of organized thrombus when compared with the aneurysms treated with GDC (87% versus 75%, P=0.008, n=11). At 3 months, both Matrix and GDC-treated aneurysms demonstrated complete clot organization. Neck tissue thickness was higher in Matrix-treated aneurysms at 14 days and 3 months, but not at 6 months. No untoward parent artery stenosis was observed in aneurysms treated with Matrix during follow-up. The angiographic cross-sectional area of the Matrix-treated aneurysms was smaller than those treated with GDC at the 3 months.
  
  
  CONCLUSIONS
  Matrix accelerated aneurysm fibrosis and neointima formation without parent artery stenosis. The Matrix system might prevent aneurysmal recanalization after endovascular treatment of cerebral aneurysms.
authors.affiliation: Division of Interventional Neuroradiology, and Leo G. Rigler Radiological Research Center, University of California, Los Angeles, USA. ymurayama@jikei.ac.jp
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Murayama
authors.forename: Satoshi
authors.initials: S
authors.lastname: Tateshima
authors.forename: Nestor R
authors.initials: NR
authors.lastname: Gonzalez
authors.forename: Fernando
authors.initials: F
authors.lastname: Vinuela
mesh_terms: D020341:Absorbable Implants / Q000009:adverse effects; D000818:Animals; D019917:Blood Vessel Prosthesis Implantation / Q000295:instrumentation*; D002533:Cerebral Angiography; D004195:Disease Models, Animal; D004621:Embolization, Therapeutic; D005260:Female; D020007:Implants, Experimental / Q000009:adverse effects; D002532:Intracranial Aneurysm / Q000473:pathology / Q000601:surgery / Q000628:therapy*; D008297:Male; D011108:Polymers / Q000009:adverse effects; D012449:Safety; D013552:Swine; D016896:Treatment Outcome
chemical_list: D011108:Polymers