Vascular Brachytherapy and Coronary Stenting for De Novo Lesions

Abstract

Although vascular brachytherapy (VBT) has proved to be effective and safe for the treatment of in-stent restenosis (1-8), its role in the treatment of de novo lesions remains unclear. The clinical trials that were designed to study the effectiveness of various beta radiations for the treatment of de novo coronary lesions reported mixed results. Although feasibility studies such as the Beta Energy Restenosis Trial (BERT) (9), which used 90Sr/Y, the Proliferation Reduction and Vascular Energy trial (10), which used P-32, and the Dose-Finding Study (11), which used a Y-90 emitter, suggested the efficacy and safety of beta radiation for the prevention of restenosis of de novo lesions, the pivotal BetaCath study failed to demonstrate efficacy and raised questions about the safety of using VBT, especially as adjunct therapy to the coronary stenting of de novo lesions (12). See pages 520 and 528The main pitfalls of the BetaCath study were its high incidence of late thrombosis, which was controlled with the administration of prolonged antiplatelet therapy, and the edge effect stenosis phenomenon, which was attributed to geographical miss and insufficient coverage of the injured margins with a sufficient radiation dose (12). As a result, beta-radiation therapy was abound for the prevention of restenosis for de novo lesions and was restricted for the prevention of the recurrence of in-stent restenosis.During the last two years there have been several attempts to revisit and study the possibility of using VBT for the treatment of de novo lesions. These studies were inconclusive and had mixed results. The two studies presented in this issue of the Journal, by Serruys et al. (13) and Sabaté et al. (14), were designed to study the impact of VBT on stented coronary arteries and attempted to implement lessons from previous VBT studies with an emphasis on prolonged antiplatelet therapy-a minimum of six months-and the avoidance of geographical miss. Whereas the BetaRadiation Investigation with Direct stenting and Galileo in Europe (BRIDGE) study was a multicentered study conducted on patients with single lesions Յ18 mm, the study by Sabaté et al. (14) was a single-center study that focused on diabetic patients.The strength of these studies was that they were prospective, randomized, controlled trials that both chose a primary end point reflecting the impact of beta irradiation on neointimal proliferation at six months, either by angiographic intrastent late loss by quantitative coronary angiography in the BRIDGE study or by or intravascular ultrasound alone in the study by Sabaté et al. (14). Both studies had small patient cohorts and were underpowered to detect secondary end points such as clinical events. Nevertheless, both studies met their primary end points, although these were not translated to clinical utility. In both the BRIDGE study and the study by Sabaté et al. (14), a significant reduction in the neointimal volume was noted in the radiation group, which resulted in significantly lower late loss when compared with th...

Treatment of Stent Restenosis

“…Stent restenosis therapy headed down its own road following pivotal brachytherapy trials that demonstrated benefit among patients with ISR but not with de novo lesions (12)(13)(14)(15). Treatment of de novo lesions focused on optimization of final lumen diameter with stents.…”