Intracoronary gamma-radiation therapy after angioplasty inhibits recurrence in patients with in-stent restenosis

Background-Treatment of ill-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 gamma-radiation t herapy versus placebo on the clinical and angiographic outcomes of patients with in-stent restenosis. Methods ann Results-One hundred thirty patients with in-stent restenosis un derwent successful coronary intervention and were then blindly randomized t o receive either intracoronary gamma-radiation with Ir-192 (15 Gy) or place bo. Four independent core laboratories blinded to the treatment protocol an alyzed the angiographic and intravascular ultrasound end points of restenos is. Procedural success and in-hospital and 30-day complications were simila r among the groups. At 6 months, patients assigned to radiation therapy req uired less target lesion revascularization and target vessel revascularizat ion (9 [13.8%] and 17 [26.2%], respectively) compared with patients assigne d 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% vers us 58% for placebo, P=0.001). Freedom from major cardiac events was lower i n the radiation group (29.2% versus 67.7% for placebo, P<0.001). Conclusions-Intracoronary gamma-radiation used as adjunct therapy for patie nts with in-stent restenosis significantly reduces both angiographic and cl inical restenosis.