Brachytherapy by implantation of a radioactive stent is an alternative approach to catheter-based systems to reduce restenosis. The pilot clinical trials using 32P radioactive β-emitting stents at low-to-intermediate activity (0.5-3.0 μCi) showed that restenosis at 6 months was not different from that of currently available non-radioactive stents. The evaluation of the efficacy in reducing restenosis of radioactive stents with higher activities (3-24 μCi) started in Europe (Milan, Rotterdam and Vienna) between 1998 and 1999. In the Milan and Rotterdam experience, 32P radioactive stents with an activity of 3-12 μCi demonstrated a reduction of intra-stent restenosis to <4%. However, a high-edge restenosis > 30% was observed in the first 1-3 mm outside the stent margins. This edge effect might be due to a low dose of radiation at the stent margins combined with systematic balloon injury in the reference segments. The hypothesis that a further increase in stent activity (12-21 μCi) associated with a reduced balloon injury outside the stent could solve the problem of edge restenosis was not confirmed by the Milan experience; edge restenosis still occurred in 26% of the lesions treated by a single 32P radioactive stent, even if a nonaggressive stent implantation strategy was used. Two approaches under investigation to solve the problem of edge restenosis are: 1) lengthening the stent with a non-radioactive stent (cold-ends stent) to prevent negative remodeling; and 2) extending the area of irradiation beyond the balloon-injured area by an increased activity at the stent ends (hot-ends stent).
|Number of pages||6|
|Journal||Journal of Invasive Cardiology|
|Publication status||Published - Aug 2000|
- Coronary disease
ASJC Scopus subject areas
- Cardiology and Cardiovascular Medicine