title: Preliminary investigation of calcium alginate gel as a biocompatible material for endovascular aneurysm embolization in vivo.
abstract: OBJECTIVE
  We sought to expand our assessment of calcium alginate as an embolic agent in an aneurysm model in swine that survived from 30 to 90 days. The objective of this study was to assess the biocompatibility and stability of calcium alginate in aneurysms in vivo.
  
  
  METHODS
  Ten models were created from a venous pouch sutured to the carotid artery, simulating flow to a side-wall aneurysm. Eight swine received complete embolizations, and two were less than 50% embolized to be used as controls. Alginate and calcium chloride were injected from concentric-tube microcatheters to form a mass that filled the aneurysm pouch.
  
  
  RESULTS
  Angiography and histology verified complete aneurysm occlusion and neck healing up to 90 days in eight swine. Both control animal aneurysms ruptured within 8 days. No animals showed evidence of downstream calcium alginate gel propagation. A minor bioactive response to the alginate gel was noted at 30 days, and fibrous tissue grew over the aneurysm orifice, sealing off the defect. No degenerative or inflammatory response was observed. At 90 days, moderate fibrous tissue surrounded the alginate. Tissue growth across the aneurysm neck remained complete and stable with no signs of neointimal growth into the parent vessel.
  
  
  CONCLUSIONS
  Calcium alginate was an effective endovascular occlusion material that filled the aneurysm and provided an effective template for tissue growth across the aneurysm neck after 30 days and up to 90 days. Complete filling of the aneurysm with calcium alginate ensures stability, biocompatibility, and optimal healing for up to 90 days in swine.
authors.affiliation: Neural Engineering Laboratory, Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan, USA.
authors.forename: Timothy A
authors.initials: TA
authors.lastname: Becker
authors.forename: Mark C
authors.initials: MC
authors.lastname: Preul
authors.forename: William D
authors.initials: WD
authors.lastname: Bichard
authors.forename: Daryl R
authors.initials: DR
authors.lastname: Kipke
authors.forename: Cameron G
authors.initials: CG
authors.lastname: McDougall
mesh_terms: D000464:Alginates / Q000008:administration & dosage / Q000627:therapeutic use*; D000783:Aneurysm / Q000000981:diagnostic imaging / Q000473:pathology / Q000628:therapy*; D000818:Animals; D021721:Balloon Occlusion; D001672:Biocompatible Materials / Q000008:administration & dosage / Q000627:therapeutic use*; D017536:Carotid Artery, Common; D004195:Disease Models, Animal; D004621:Embolization, Therapeutic / Q000379:methods*; D020723:Glucuronic Acid / Q000008:administration & dosage / Q000627:therapeutic use; D006603:Hexuronic Acids / Q000008:administration & dosage / Q000627:therapeutic use; D008422:Materials Testing; D011859:Radiography; D013552:Swine
chemical_list: D000464:Alginates; D001672:Biocompatible Materials; D006603:Hexuronic Acids; D020723:Glucuronic Acid