title: Late neointimal tissue growth behind the stent after intravascular gamma-radiation.
abstract: OBJECTIVE
  To determine the nature of the changes of the vascular wall after intravascular brachytherapy in stented arteries leading to incomplete stent apposition.
  
  
  METHODS
  Stents were implanted in the infrarenal aortas of rabbits, and gamma-intravascular brachytherapy (18 Gy) or a sham radiation procedure was immediately implemented. The arteries were harvested at 6 months for histologic analyses.
  
  
  RESULTS
  The external elastic lamina area, as well as the vascular wall area behind the stent, were significantly greater in irradiated vs. control arteries (8.94 +/- 0.68 mm2 vs. 6.87 +/- 0.40 mm2 [p <0.001] and 1.56 +/- 0.13 mm2 vs. 0.72 +/- 0.07 mm2 [p <0.001], respectively). The ratio of the intimal area behind the stent related to the total intimal area was greater in the irradiated segments (control vs. irradiated: 9.0% +/- 5.9% vs. 55.3% +/- 15.5%, p <0.05). Neointimal growth of the irradiated vessels outside the stent was characterized by marked fibrin depositions and an inflammatory response around the stent struts.
  
  
  CONCLUSIONS
  Our study revealed the presence of a neointimal layer specifically located behind the stent, which represented the result of an unhealed fibrin-rich tissue growth process 6 months after intravascular brachytherapy.
authors.affiliation: Laboratory of Cardiovascular and Experimental Physiopathology and Pharmacology, Faculty of Medicine, University of Burgundy, Dijon, France.
authors.forename: David
authors.initials: D
authors.lastname: Busseuil
authors.forename: Marianne
authors.initials: M
authors.lastname: Zeller
authors.forename: Yves
authors.initials: Y
authors.lastname: Cottin
authors.forename: Philippe
authors.initials: P
authors.lastname: Maingon
authors.forename: Isabelle
authors.initials: I
authors.lastname: Barillot
authors.forename: Philippe
authors.initials: P
authors.lastname: Allouch
authors.forename: Tibor
authors.initials: T
authors.lastname: Ponnelle
authors.forename: Antoine
authors.initials: A
authors.lastname: Bril
authors.forename: François
authors.initials: F
authors.lastname: Briot
authors.forename: Jean-Eric
authors.initials: JE
authors.lastname: Wolf
authors.forename: Luc
authors.initials: L
authors.lastname: Rochette
mesh_terms: D000818:Animals; D001012:Aorta, Abdominal / Q000528:radiation effects; D001918:Brachytherapy / Q000009:adverse effects*; D003251:Constriction, Pathologic / Q000209:etiology; D005720:Gamma Rays; D008297:Male; D011817:Rabbits; D015607:Stents; D017539:Tunica Intima / Q000254:growth & development / Q000528:radiation effects*