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.