Intracoronary β-radiation therapy inhibits recurrence of in-stent restenosis

Background - Intracoronary γ-radiation therapy reduces recurrent in- stent restenosis (ISR). This study, BETA WRIST (Washington Radiation for In- Stent restenosis Trial) was designed to examine the efficacy and safety of the β-emitter 90-yttrium for the prevention of recurrent ISR. Methods and Results - A total of 50 consecutive patients with ISR in native coronaries underwent percutaneous transluminal coronary angioplasty, laser angioplasty, rotational atherectomy, and/or stent implantation. Afterward, a segmented balloon catheter was positioned and automatically loaded with a 90-yttrium, 0.014-inch source wire that was 29 mm in length to deliver a dose of 20.6 Gy at 1.0 mm from the balloon surface. In 17 patients, manual stepping of the radiation catheter was necessary for lesions >25 mm in length. The radiation was delivered successfully to all patients, with a mean dwell time of 3.0±0.4 minutes. Fractionation of the dose due to ischemia was required in 11 patients. At 6 months, the binary angiographic restenosis rate was 22%, the target lesion revascularization rate was 26%, and the target vessel revascularization rate was 34%; all rates were significantly lower than those of the placebo group of γ-WRIST. Conclusions - β-Radiation with a 90- yttrium source used as adjunct therapy for patients with ISR results in a lower-than-expected rate of angiographic and clinical restenosis.