beta-particle-emitting radioactive stent implantation - A safety and feasibility study

Background-This study represents the Heart Center Rotterdam's contribution to the Isostents fur Restenosis Intervention Study, a nonrandomized multice nter trial evaluating the safety and feasibility of the radioactive Isosten t in patients with single coronary artery disease. Restenosis after stent i mplantation is primarily caused by neointimal hyperplasia. In animal studie s, beta-particle-emitting radioactive stents decrease neointimal hyperplasi a by inhibiting smooth muscle cell proliferation. Methods non Results-The radioisotope P-32, a beta-particle emitter with a h alf-life of 14.3 days, was directly embedded into the Isostent. The calcula ted range of radioactivity was 0.75 to 1.5 mu Ci. Quantitative coronary ang iography measurements were performed before and after the procedure and at 6-month follow-up. A total of 31 radioactive stents were used in 26 patient s; 30 (97%) were successfully implanted, and 1 was embolized, Treated lesio ns were in the left anterior descending coronary artery (n=12), the right c oronary artery (n=8), or the left circumflex coronary artery (n=6). Five pa tients received additional, nonradioactive stents. Treated lesion lengths w ere 13+/-4 mm, with a reference diameter of 2.93 +/- 0.47 mm. Minimum lumen diameter increased from 0.87+/-0.28 mm preprocedure to 2.84+/-0.35 mm post procedure. No in-hospital adverse cardiac events occurred, All patients rec eived aspirin indefinitely and ticlopidine for 4 weeks. Twenty-three patien ts (88%) returned for 6-month angiographic follow-up; 17% of them had in-st ent restenosis, and 13% had repeat revascularization. No restenosis was obs erved at the stent edges, Minimum lumen diameter at follow-up averaged 1.85 +/- 0.69 mm, which resulted in a late loss of 0.99 +/- 0.59 mm and a late loss index of 0.53+/-0.35. No other major cardiac events occurred during th e 6-month follow-up. Conclusions-The use of radioactive stents with an activity of 0.75 to 1.5 m u Ci is safe and feasible.