title: Biocompatibility of a new device of self-expandable covered and non-covered tracheal stent: comparative study in rats.
abstract: OBJECTIVE
  To investigate the compatibility of a new model of self-expandable tracheal stent in rats.
  
  
  METHODS
  A new device of polyurethane covered and non - covered stent was placed in the trachea of Wistar rats. Animals were distributed in two groups: the polyurethane covered and non-covered group. Macroscopic parameters included position within the tracheal lumen, adherence to the mucosa, degree of dilatation, permeability and internal diameter. Microscopic findings evaluated were: incorporation, inflammatory activity, granulation tissue and epithelial revetment injuries. The observation follow-up was six weeks. All parameters were quantified based on determined score values. Incorporation of the stents was evaluated based on the observation if the stent was fixed into the trachea or if it could be removed. Degree of dilatation was performed by external diameter measurements. Granulation tissue was evaluated by measurements of height of the tissue growing into the tracheal lumen.
  
  
  RESULTS
  100% of non-covered stents had total attachment to mucosa and 100% of polyurethane covered type had adherence only. Regarding dilatation, granulation tissue, inflammatory activity and internal diameter measurements, there were no significant differences between the groups. Pathological tracheal wall injuries were present in both groups.
  
  
  CONCLUSIONS
  Both models of stent demonstrated biocompatibility with the trachea. Rats are suitable for an experimental model of tracheal stent study.
authors: Division of General Thoracic Surgery, UMC, Mogi das Cruzes, SP, Brazil. olavorr@uol.com.br
authors: Olavo Ribeiro
authors: OR
authors: Rodrigues
authors: Hélio
authors: H
authors: Minamoto
authors: Mauro
authors: M
authors: Canzian
authors: Aristides Tadeu
authors: AT
authors: Correia
authors: Fabio Biscegli
authors: FB
authors: Jatene
mesh_terms: D000497:Alloys / Q000627:therapeutic use; D000818:Animals; D001672:Biocompatible Materials / Q000627:therapeutic use*; D005260:Female; D008297:Male; D008422:Materials Testing; D023421:Models, Animal; D011140:Polyurethanes / Q000627:therapeutic use; D051381:Rats; D017208:Rats, Wistar; D015203:Reproducibility of Results; D015607:Stents; D014132:Trachea / Q000473:pathology / Q000601:surgery*
chemical_list: D000497:Alloys; D001672:Biocompatible Materials; D011140:Polyurethanes; C013616:nitinol