Percutaneous Interventions in Radiation- Associated Coronary In-Stent Restenosis P. Wexberg, 1 G. Beran, 1 I. Lang, 1 P. Siostrzonek, 1 C. Kirisits, 2 D. Glogar, 1 M. Gottsauner-Wolf 1 1 Division of Cardiology, Department of Internal Medicine II, University of Vienna, Austria 2 Division of Medical Radiation Physics, Department of Radiotherapy and Radiobiology, University of Vienna, Austria Abstract This study was performed to evaluate the outcome of per- cutaneous revascularization in “edge restenoses” developing after radioactive stent implantation in de novo and in-stent lesions. Twenty-one consecutive patients undergoing target lesion revascularization (TLR) at any follow-up after phos- phorus-32 radioactive stent implantation were included in this study. We assessed the incidence of death, myocardial infarction, repeated TLR and recurrent angina over the fol- lowing 18 months. After 6 months, TLR rate was 28.6%, and no stent thromboses, deaths or Q-wave myocardial infarc- tions occurred. Among the patients with TLR there were significantly more subjects who had received a radioactive stent in a previous in-stent restenosis (66.7% vs. 0% in patients without second restenosis; P  0.001), or who had received two radioactive stents (83.3% vs. 33.3%; P = 0.038). After 18 months, TLR rate was 33.3%, and two patients (9.5%) had died. Restenosis after intravascular ra- diotherapy can be safely treated by percutaneous interven- tional techniques, yielding an acceptable clinical result within 18 months. Key words: Coronary artery disease—Intravascular brachy- therapy—Percutaneous coronary intervention—Restenosis Intravascular brachytherapy has become a widely applied method for reducing restenosis after percutaneous coronary interventions. However, its success may be severely limited by a specific type of restenosis occurring predominantly at the edges of the treated segments (regardless of the source type), which is caused by regional underdosing [1]. The highest incidence of this “candy wrapper restenosis” [2] was found after the implantation of radioactive stents [3] due to the steep dose decline of beta radiation [4]. The development of hot-end and cold-end stents with an increased or de- creased radioactivity at the stent edges, respectively, led only to a different pattern but not to a decreased incidence of restenosis [5, 6]. Substantial histological differences exist between the vascular response after brachytherapy and non- radioactive stenting, such as delayed reendothelialization [7], which might affect the vascular response after retreat- ment. It is unknown whether this “edge effect” leads to an increased restenosis rate after repeated revascularization. Therefore, the present study was performed to evaluate the 6- (mid-term) and 18-month (long-term) outcome after re- peated revascularization of restenosed radioactive stents. Materials and Methods The European P-32 Dose Response Study was designed to test radioactive stents implanted in de novo and restenotic coronary lesions with regard to their efficacy in reducing restenosis. It was performed in accordance with the Helsinki Declaration of 1964, as revised in 1989, and was approved by the local Medical Ethics Committee. All patients gave written informed consent to partici- pation. From January to November 1999, 42 patients underwent implantation of phosphorus-32 (P-32) impregnated BX-stents (Isostent Inc., Belmont, CA, USA) at our institution. The stents had a length of 15 mm and a nominal diameter of 3.0 mm or 3.5 mm in the expanded mode, and were available with an initial activity of up to 24 Ci (888 kBq) with a range between 5.36 and 20.77 Ci at implantation. Inclusion criteria, implantation technique and stent design have been previously published elsewhere [3], as was the methodology of quantitative coronary angiography (QCA) [8]. All patients received 100 mg acetylsalicylic acid and 500 mg ticlopi- dine or 75 mg clopidogrel (in case of allergic reactions to ticlopi- dine) p. d. for 3 months. They were called in for follow-up angiography 6 and 12 months after stent implantation. A stenosis greater than 50%, per se, was not an indication for target lesion revascularization (TLR) in the absence of clinical findings. TLR was performed only with clinically symptomatic restenosis, which resulted in either a positive stress test or recurrent angina in the Correspondence to: P. Wexberg, M.D., B.M., Division of Cardiology, Department of Internal Medicine II, University of Vienna, Währinger Gürtel 18-20, A-1090 Vienna, Austria; email: paul.wexberg@univie.ac.at Cardio V ascular and Interventional Radiology © Springer-Verlag New York, Inc. 2003 Cardiovasc Intervent Radiol (2003) 26:154 –157 Published Online: 18 March 2003 DOI: 10.1007/s00270-002-2644-z