Intracoronary γ-Radiation Therapy After Angioplasty Inhibits Recurrence in Patients With In-Stent Restenosis

Background —Treatment of in-stent restenosis presents a critical limitation of intracoronary stent implantation. Ionizing radiation has been shown to decrease neointimal formation within stents in animal models and in initial clinical trials. We studied the effects of intracoronary γ-radiation therapy versus placebo on the clinical and angiographic outcomes of patients with in-stent restenosis. Methods and Results —One hundred thirty patients with in-stent restenosis underwent successful coronary intervention and were then blindly randomized to receive either intracoronary γ-radiation with 192 Ir (15 Gy) or placebo. Four independent core laboratories blinded to the treatment protocol analyzed the angiographic and intravascular ultrasound end points of restenosis. Procedural success and in-hospital and 30-day complications were similar among the groups. At 6 months, patients assigned to radiation therapy required less target lesion revascularization and target vessel revascularization (9 [13.8%] and 17 [26.2%], respectively) compared with patients assigned to placebo (41 [63.1%, P =0.0001] and 44 [67.7%, P =0.0001], respectively). Binary angiographic restenosis was lower in the irradiated group (19% versus 58% for placebo, P =0.001). Freedom from major cardiac events was lower in the radiation group (29.2% versus 67.7% for placebo, P <0.001). Conclusions —Intracoronary γ-radiation used as adjunct therapy for patients with in-stent restenosis significantly reduces both angiographic and clinical restenosis.