Usefulness of Beta Radiation for De Novo and In-Stent Restenotic Lesions in Saphenous Vein Grafts Gregg W. Stone, MD, Roxana Mehran, MD, Mark Midei, MD, Ron Waksman, MD, Gary L. Schaer, MD, Manuela Negoita, MD, Alexandra J. Lansky, MD, and Maurice Buchbinder, MD, for the SVG BRITE Investigators Following successful angioplasty of 49 saphenous vein graft lesions, a novel, self-centering phospho- rus-32 solid foil  source encapsulated within a dual- balloon membrane was used to deliver 20 Gy 1 mm into the vessel wall. Clinical and angiographic recur- rence rates at 12 months were low, especially in de novo lesions. 2003 by Excerpta Medica, Inc. (Am J Cardiol 2003;92:312–314) P ercutaneous coronary intervention (PCI) in saphe- nous vein grafts (SVGs) is associated with a high rate of clinical and angiographic restenosis. 1–3 Al- though restenosis develops less commonly after stent implantation than after balloon angioplasty in SVGs, 3 recurrent restenosis often occurs after repeat PCI of in-stent restenosis (ISR). 4,5 Vascular brachytherapy, using  and  sources, has been shown to reduce the recurrent restenosis rate after PCI of ISR lesions in native coronary arteries. 6,7 The efficacy of -radiation in ISR lesions in SVGs has been demonstrated, 8 al- though -radiation has not been studied for this ap- plication. Moreover, neither  nor  brachytherapy has been studied in de novo lesions of SVGs. There- fore, we examined the safety and efficacy of a novel  vascular brachytherapy catheter for the treatment of de novo and ISR lesions in SVGs. ••• We enrolled 49 patients at 8 participating centers in the United States and Europe in a phase I trial of the RDX brachytherapy catheter (Radiance Medical Sys- tems, Irvine, California) under a Food and Drug Ad- ministration-approved Investigational Device Exemp- tion. Patients who underwent successful PCI of a single de novo or ISR lesion in a nonoccluded SVG with a reference vessel diameter 3.0 to 4.5 mm and lesion length 45 mm were eligible for enrollment. Major exclusion criteria included acute or recent myo- cardial infarction, ejection fraction 25%, cardio- genic shock, renal insufficiency, angiographic throm- bus, lesion within 5 mm of the distal anastomosis, and prior brachytherapy to the chest. The protocol was approved by the institutional review board at each center, and each patient provided written informed consent. As previously described, 9,10 the RDX system con- sists of a solid phosphorus-32 (P-32) pure -emitting foil source (activity 25 to 35 mCi) encased between 2 standard balloon angioplasty layers (3.0 to 4.5 mm diameters available). The source is delivered prepack- aged and sterile within an acrylic block and is passed over a commercial 0.014-in guidewire to the lesion site 10 ; no additional shielding is necessary once the source is within the patient. The 33-mm source length allows for treatment of lesions 25 mm long; up to 1 manual step was permitted for longer lesions. The system is auto-centering; radiation is delivered at the interface of the inflated balloon and the vessel wall, facilitating accurate dosimetry and penetration around luminal objects, such as stents. 9,10 Dosimetry has been established to deliver 20 Gy 1 mm into the vessel wall and incorporates inflation/deflation cycles of 90 and 30 seconds, respectively, to minimize ischemia. After the procedure, patients were treated with aspirin and either clopidogrel or ticlopidine for 12 months or 3 months depending on whether or not new stents were implanted, respectively. Clinical fol- low-up was performed at 6 and 12 months, and repeat angiography was prespecified at 6 months for all pa- tients. Clinical data were entered into a computerized database at a central data-coordinating center. Source documents were collected and verified for accuracy. All clinical events were adjudicated by a central com- mittee. Angiograms were interpreted at an indepen- dent core angiographic laboratory using specific tech- niques previously described and validated for brachy- therapy. 11 Categoric variables were compared by the likeli- hood ratio chi-square test or Fisher’s exact test. Con- tinuous variables are presented as mean  SD and were compared using the unpaired t test. A total of 49 patients were enrolled, including 24 with de novo and 25 with ISR SVG lesions (Table 1). The population was elderly and contained a high fre- quency of patients with diabetes mellitus, hyperten- sion, hyperlipidemia, and prior myocardial infarction. The SVG supplied the left anterior descending, left circumflex, and right coronary artery distributions in 26%, 37%, and 37% of patients, respectively. New stents were implanted in most patients with de novo lesions versus 1/3 of patients with ISR lesions (Table 2). Adjunctive laser ablation was performed in 1 patient (with an ISR lesion). Atherectomy and other debulking devices were not utilized. Technical suc- From the Cardiovascular Research Foundation and Lenox Hill Heart and Vascular Institute, New York, New York; St. Joseph’s Hospital, Towson, Maryland; Washington Hospital Center, Washington, DC; Rush Presbyterian—St. Luke’s Medical Center, Chicago, Illinois; and Scripps Memorial Hospital, San Diego, California. This report was supported by Radiance Medical Systems, Irvine, California. Dr. Stone’s address is: The Cardiovascular Research Foundation, 55 East 59th Street, 6th Floor, New York, New York 10022. E-mail: gstone@crf.org. Manuscript received March 18, 2003; revised manu- script received and accepted April 21, 2003. 312 ©2003 by Excerpta Medica, Inc. All rights reserved. 0002-9149/03/$–see front matter The American Journal of Cardiology Vol. 92 August 1, 2003 doi:10.1016/S0002-9149(03)00635-0