The pattern of restenosis and vascular remodelling after cold-end radioactive stent implantation

Background Edge restenosis is a major problem after radioactive stenting. T he cold-end stent has a radioactive mid-segment (15.9 mm) and non-radioacti ve proximal and distal 5.7 mm segments. Conceptually this may negate the im pact of negative vascular remodelling at the edge of the radiation. Method and Results ECG-gated intravascular ultrasound with three-dimensiona l reconstruction was performed post-stent implantation and at the 6-month f ollow-up to assess restenosis within the margins of the stent and at the st ent edges in 16 patients. Angiographic restenosis was witnessed in four pat ients, all in the proximal in-stent position. By intravascular ultrasound i n-stent neointimal hyperplasia, with a >50%, stented cross-sectional area, was seen in eight patients. This was witnessed proximally (n=2), distally ( n=2) and in both segments (n=4). Echolucent tissue, dubbed the 'black hole' wets seen as a significant component of neointimal hyperplasia in six out of the eight cases of restenosis. Neointimal hyperplasia was inhibited in t he area of radiation: A neointimal hyperplasia=3.72 mm(3) (8.6%); in-stent at the edges of radiation proximally and distally A neointimal hyperplasia was 7.9 mm(3) (19.0%) and 11.4 mm(3) (25.6%), respectively (P=0.017). At th e stent edges there was no significant change in lumen volume. Conclusions Cold-end stenting results in increased neointimal hyperplasia i n in-stent non-radioactive segments.