Intracoronary beta-irradiation with a liquid Re-188-filled balloon - Six-month results from a clinical safety and feasibility study

Background-Coronary irradiation is a new concept to reduce restenosis. We e valuated the feasibility and safety of intracoronary irradiation with a bal loon catheter filled with Re-188, a liquid, high-energy beta-emitter. Methods and Results-Irradiation with 15 Gy at 0.5-mm tissue depth was perfo rmed in 28 lesions after balloon dilation (n=9) or stenting (n=19). Lesions included 19 de novo stenoses, 4 occlusions, and 5 restenoses. Irradiation time was 515+/-199 seconds in 1 to 4 fractions. There were no procedural co mplications. One patient died of noncardiac causes at day 23. One asymptoma tic patient refused 6-month angiography. Quantitative angiography after int ervention showed a reference diameter of 2.77+/-0.35 mm and a minimal lumen diameter of 2.36+/-0.43 mm. At 6-month follow-up, minimal lumen diameter w as 1.45+/-0.88 mm (late loss index 0.57). Target lesion restenosis rate (>5 0% in diameter) was low (12%; 3 of 26). In addition, we observed 9 stenoses at the proximal or distal end of the irradiation zone, potentially caused by the short irradiation segment and the decreasing irradiation dose at its borders ("edge" stenoses). The total restenosis rate was 46% and was signi ficantly lower (29% vs 70%, P=0.042) when the length of the irradiated segm ent was more than twice the lesion length. Conclusions-Coronary irradiation with a Re-188-filled balloon is technicall y feasible and safe, requiring only standard percutaneous transluminal coro nary angioplasty techniques. The target lesion restenosis rate was low. The observed edge stenoses appear to be avoidable by increasing the length of the irradiated segment.