The Dresden in-stent restenosis radiation trial (DIRRT) with liquid-filled 188Re balloon

Full text: In some studies intracoronary radiation therapy (IRT) to minimize the restenosis rate after PTCA proved to be effective. We evaluated the performance, safety and effectiveness of IRT with 188Re-perrhenate filled into a standard PTCA balloon. This kind of IRT allows a self-centering homogenous dose distribution to the vessel wall. 107 patients (pts) with a mean age of 63 years (81 m, 26 fin) with in-stent restenosis (type B in 39 %, type C in 61 %) and proven ischemia were included. After routine re-PTCA with or without additional stent implantation a second standard balloon was placed into the PTCA area and filled with β--emitting liquid 188Re at 3 atm. Irradiation time was 525 ± 167 sec to achieve a dose of 30 Gy at 0.5 mm depth of the vessel wall. In only one procedure there was a disconnection of the 188Re containing system and the catheter but no contamination of the cath table or lab was measured. In 16 coronaries 21 stents were additionally implanted. In the follow-up 4 stent thromboses (1 day, 37 days, 2 x 6 months) with subsequent myocardial infarction were noticed, all in pts with additionally implanted stents. 57 pts had control angiography after 4 to 6 months after therapy and 41 after one year. Restenosis (stenosis > 50 % of luminal diameter) was shown in 9 out of 12 pts (75 %) with additionally implanted stents but only in 4 out of 24 pts (17 %) with PTCA alone. Reocclusion was noticed in 3 (25 %) pts with additional stent but only in 1 pt (4 %) without. No re-restenosis occurred in 20 patients which were without finding after 6 months. Intracoronary radiation therapy (IRT) with β--emitting liquid-filled 188Re balloon is a safe and effective therapy method which might be used routinely. Long-term results seem satisfactory in a patient group with in-stent restenosis and high risk of re-restenosis. But the positive effect of irradiation is abolished if an additional stent after PTCA is needed. (author)