Intracoronary radiation with gamma wire inhibits recurrent in-stent restenosis Ron Waksman a, *, Balram Bhargava a , Rosanna C. Chan a , Warren Sherman b , Juliana Pisch b , Gary S. Mintz a , Alexandra J. Lansky a , Javed Ahmed a , Nancy A. Ricci c , Sam F. Liprie c a Washington Hospital Center, 110 Irving Street North West, Suite 4B-1, Washington, DC 20010, USA b Beth Israel Hospital, New York, NY, USA c US Surgical, Norwalk, CT, USA Abstract To study the safety and efficacy of intracoronary gamma radiation delivered via a new high-activity 192 Ir source wire for the treatment of in-stent restenosis. In-stent restenosis results from neointimal tissue proliferation especially in its diffused form and presents a therapeutic challenge. Gamma radiation has been shown to decrease neointima formation within stents in animal models and in initial clinical trials. A total of 26 patients with in-stent restenosis underwent successful intervention and was treated with open-label 192 Ir using a high-activity line source. The specific activity of the source wire was 372  51 mCi, and the dwell time was 10.8  1.9 min. Primary endpoints were freedom from death, myocardial infraction (MI), and repeat target lesion revascularization (TLR) at 6 months. Secondary endpoints included angiographic restenosis and intravascular ultrasound (IVUS) neointimal hyperplasia. Procedural success was high (96.2%), and in-hospital and 30-day complications were low with no deaths, MI, or requirement for repeat revascularization. At 6 months, event-free survival was 85%: one patient required repeat PTCA, one underwent bypass surgery, and two had an MI. Baseline lesion length measured 15.77 mm. Follow-up angiography was available in 21/25 (84%) patients. The binary restenosis rates were 19.0% (4/21) in-stent and 23.8% (5/21) in-lesion. Follow-up IVUS was available in 20/25 patients. There was no increase in intimal hyperplasia from postintervention to follow-up (3.11.8 vs. 3.41.8 mm 2 ; P = .32). Eight patients had a reduction of neointimal intimal tissue at follow-up. These results indicate that intracoronary gamma radiation with the Angiorad source wire is safe and effective in preventing in- stent restenosis. D 2001 Elsevier Science Inc. All rights reserved. Keywords: Radiation; Restenosis; Gamma emitters 1. Introduction Stents reduce restenosis by providing a larger initial lumen and by reducing early recoil and/or late constrictive remodeling [1 ± 3]. In-stent restenosis results from neointimal tissue proliferation Ð distributed either focally or diffusely over the length of the stent [4]. Especially in its diffused form, in-stent restenosis presents a therapeutic challenge [5 ± 7]. Studies with intracoronary radiation using gamma and beta emitters delivered by catheter-based systems have demonstrated a reduction in neointima formation in animal studies [8 ± 17]. Feasibility clinical trials have indicated that gamma radiation therapy reduces recurrent in-stent resteno- sis [15±17]. In the present study, we evaluated a new 192 Ir source wire to treat patients with in-stent restenosis. 2. Methods This clinical trial was sponsored by an Investigational Device Exemption granted by the Food and Drug Admin- istration and approved by the Institutional Review Board and the Radiation Safety Committee at the Washington Hospital Center. The study was monitored by an external data and safety-monitoring board. Informed consent was obtained from all patients before enrollment. * Corresponding author. Tel.: +1-202-877-8575; fax: +1-202-877- 0243. E-mail address: rxw8@mhg.edu (R. Waksman). Cardiovascular Radiation Medicine 2 (2001) 63 ± 68 1522-1865/01/$ ± see front matter D 2001 Elsevier Science Inc. All rights reserved. PII:S1522-1865(00)00086-X