[Secondary effects of brachytherapy in the treatment of coronary restenosis]

Brachytherapy is proposed for the treatment or prevention of coronary restenosis with encouraging results, especially in intra-stent restenosis. The results of the first clinical studies show benefit, for example those of the American SCRIPPS trial with a 3 year follow-up. However, recent reports in the literature have described secondary effects associated with this technique: 1) stenoses occurring at the limits of the irradiated segments which are attributed to a proliferative effect of low doses on damaged tissue; 2) late occlusions at the irradiated site: their incidence is estimated at 9% at 6 months. The mechanisms of these thromboses are not understood but delayed re-endothelialisation probably plays a rôle; 3) finally, irradiation is associated with uncovered dissection probably related to delayed healing. Other long-term trials are necessary to provide a more complete assessment of the secondary effects of brachytherapy, especially with regards to their mechanisms, prevention and treatment.