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

Background-Intracoronary gamma-radiation therapy reduces recurrent in-stent restenosis (ISR). This study, BETA WRIST (Washington Radiation for In-Sten t restenosis Trial) was designed to examine the efficacy and safety of the beta-emitter 90-yttrium for the prevention of recurrent ISR. Methods and Results-A total of 50 consecutive patients with ISR in native c oronaries underwent percutaneous transluminal coronary angioplasty, laser a ngioplasty, 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 do se of 20.6 Gy at 1.0 mm from the balloon surface. In 17 patients, manual st epping of the radiation catheter was necessary for lesions >25 mm in length . The radiation was delivered successfully to all patients, with a mean dwe ll 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 r ate was 22%, the target lesion revascularization rate was 26%, and the targ et vessel revascularization rate was 34%; all rates were significantly lowe r than those of the placebo group of gamma-WRIST. Conclusions-beta-Radiation with a 90-yttrium source used as adjunct therapy for patients with ISR results in a lower-than-expected rate of angiographi c and clinical restenosis.