Edge Restenosis After Implantation of High Activity 32 P Radioactive β-Emitting Stents

Abstract

Background—A high restenosis rate has been reported at the edges (“edge restenosis”) of 32P radioactive stents with an initial activity level of 3 to 12 μCi. This edge effect might be due to balloon injury and to a low dose of radiation at the stent margins. The aim of this study was to evaluate whether the implantation of 32P radioactive stents with a higher activity level (12 to 21 μCi) combined with a nonaggressive stent implantation strategy could solve the problem of edge restenosis. Methods and Results—We compared the results of lesions treated with single radioactive BX stents with an activity of 12 to 21 μCi (group 2, n=54 lesions) with the results of lesions treated by single radioactive BX stents with an initial activity level of 3 to 12 μCi (group 1, n=42 lesions). There were no procedural events. At the 6-month follow-up, no myocardial infarctions, deaths, or stent thromboses had occurred. Intrastent binary restenosis was 0% in group 1 versus 4% in group 2 (n=2, both at the ostium of the right...