Late neointimal tissue growth behind the stent after intravascular γ-radiation

Abstract Purpose To determine the nature of the changes of the vascular wall after intravascular brachytherapy in stented arteries leading to incomplete stent apposition. Methods and materials Stents were implanted in the infrarenal aortas of rabbits, and γ-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 mm 2 vs. 6.87 ± 0.40 mm 2 [ p 2 vs. 0.72 ± 0.07 mm 2 [ p p Conclusion 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.