title: Tracheal Self-Expandable Metallic Stents: A Comparative Study of Three Different Stents in a Rabbit Model.
abstract: BACKGROUND
  The objective of this study was to assess tracheal reactivity after the deployment of different self-expandable metal stents (SEMS).
  
  
  METHODS
  Forty female New Zealand rabbits were divided into four groups. Three groups received three different SEMS: steel (ST), nitinol (NiTi), or nitinol drug-eluting stent (DES); the fourth group was the control group (no stent). Stents were deployed percutaneously under fluoroscopic guidance. Animals were assessed by multi-slice, computed tomography (CT) scans, and tracheas were collected for anatomical pathology (AP) study. Data from CT and AP were statistically analyzed and correlated.
  
  
  RESULTS
  The DES group had the longest stenosis (20.51±14.08mm vs. 5.84±12.43 and 6.57±6.54mm in NiTi and ST, respectively, day 30; P<.05), and higher granuloma formation on CT (50% of cases). The NiTi group showed the lowest grade of stenosis (2.86±6.91% vs. 11.28±13.98 and 15.54±25.95% in DES and ST, respectively; P<.05). The AP study revealed that the ST group developed intense proliferative reactivity compared to the other groups. In the DES group, a destructive response was observed in 70% of the animals, while the NiTi was the least reactive stent. CT was more effective in detecting wall thickening (positive correlation of 68.9%; P<.001) than granuloma (not significant).
  
  
  CONCLUSIONS
  The ST group developed granulomas and significant stenosis. NiTi was the least reactive stent, while DES caused significant lesions that may be related to drug dosage. This type of DES stent is therefore not recommended for the treatment of tracheobronchial stenosis.
authors.affiliation: Grupo de Investigación en Técnicas de Mínima Invasión (GITMI) del Gobierno de Aragón, Universidad de Zaragoza, Zaragoza, España.
authors.forename: Carolina
authors.initials: C
authors.lastname: Serrano
authors.affiliation: Grupo de Investigación en Técnicas de Mínima Invasión (GITMI) del Gobierno de Aragón, Universidad de Zaragoza, Zaragoza, España.
authors.forename: Fernando
authors.initials: F
authors.lastname: Lostalé
authors.affiliation: Instituto de Biomedicina de Sevilla (IBIS), Hospital Virgen del Rocío/CSIC/Universidad de Sevilla, Sevilla, España.
authors.forename: Francisco
authors.initials: F
authors.lastname: Rodríguez-Panadero
authors.affiliation: Departamento de Patología Animal, Universidad de Zaragoza, Zaragoza, España.
authors.forename: Ignacio de
authors.initials: Id
authors.lastname: Blas
authors.affiliation: Grupo de Investigación en Técnicas de Mínima Invasión (GITMI) del Gobierno de Aragón, Universidad de Zaragoza, Zaragoza, España.
authors.forename: Alicia
authors.initials: A
authors.lastname: Laborda
authors.affiliation: Grupo de Investigación en Técnicas de Mínima Invasión (GITMI) del Gobierno de Aragón, Universidad de Zaragoza, Zaragoza, España; CIBER Bioingeniería, Biomateriales y Nanomedicina (BBN), Zaragoza, España. Electronic address: mgregori@unizar.es.
authors.forename: Miguel Angel
authors.initials: MA
authors.lastname: de Gregorio
mesh_terms: D000497:Alloys; D000818:Animals; D005260:Female; D005471:Fluoroscopy; D006099:Granuloma / Q000209:etiology*; D023421:Models, Animal; D061330:Multidetector Computed Tomography; D011817:Rabbits; D000069322:Self Expandable Metallic Stents / Q000009:adverse effects*; D013232:Steel; D014133:Tracheal Diseases / Q000209:etiology*; D014135:Tracheal Stenosis / Q000628:therapy*
chemical_list: D000497:Alloys; D013232:Steel; C013616:nitinol
keywords: Airway obstruction; Animal models; Drug-eluting stents; Estenosis traqueal; Experimentación animal; Obstrucción de la vía aérea; Stents; Stents liberadores de fármacos; Tracheal stenosis