Late neointimal tissue growth behind the stent after intravascular gamma-radiation.
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.
Busseuil
David
D
Laboratory of Cardiovascular and Experimental Physiopathology and Pharmacology, Faculty of Medicine, University of Burgundy, Dijon, France.
Zeller
Marianne
M
Cottin
Yves
Y
Maingon
Philippe
P
Barillot
Isabelle
I
Allouch
Philippe
P
Ponnelle
Tibor
T
Bril
Antoine
A
Briot
François
F
Wolf
Jean-Eric
JE
Rochette
Luc
L
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*