Aims This study is the contribution by the Thoraxcenter, Rotterdam, to the European32P Dose Response Trial, a non-randomized multicentre trial to evaluate the safety and efficacy of the radioactive Isostent™ in patients with single coronary artery disease.
Methods and Results The radioactivity of the stent at implantation was 6–12μCi. All patients received aspirin indefinitely and either ticlopidine or clopidogrel for 3 months. Quantitative coronary angiography measurements of both the stent area and the target lesion (stent area and up to 5mm proximal and distal to the stent edges) were performed pre- and post-procedure and at the 5-month follow-up. Forty-two radioactive stents were implanted in 40 patients. Treated vessels were the left anterior descending coronary artery (n=20), right coronary artery (n=10) or left circumflex artery (n=10). Eight patients received additional non-radioactive stents. Lesion length measured 10±3mm with a reference diameter of 3·07±0·69mm. Minimal lumen diameter increased from 0·98±0·53mm pre-procedure to 2·29±0·52mm (target lesion) and 2·57±0·44mm (stent area) post-procedure. There was one procedural non-Q wave myocardial infarction, due to transient thrombotic closure. Thirty-six patients returned for angiographical follow-up. Two patients had a total occlusion proximal to the radioactive stent. Of the patent vessels, none had in-stent restenosis. Edge restenosis was observed in 44%, occurring predominantly at the proximal edge. Target lesion revascularization was performed in 10 patients and target vessel revascularization in one patient. No additional clinical end-points occurred during follow-up. The minimal lumen diameter at follow-up averaged 1·66±0·71mm (target lesion) and 2·12±0·72 (stent area); therefore late loss was 0·63±0·69 (target lesion) and 0·46±0·76 (stent area), resulting in a late loss index of 0·65±1·15 (target lesion) and 0·30±0·53 (stent area).
Conclusion These results indicate that the use of radioactive stents is safe and feasible, however, the high incidence of edge restenosis makes this technique currently clinically non-applicable.