Recently, ionizing radiation has bean shown to decrease the proliferat
ive response to injury in animal models of restenosis. The Scripps Cor
onary Radiation to inhibit Proliferation Post-Stenting (SCRIPPS) trial
was a double-blind, placebo-controlled, randomized trial to test this
new treatment modality in restenotic stented human coronary arteries.
Patients with previous restenosis and stent implantation were randomi
zed to receive catheter-based radiation with Iridium-192 or a placebo
using a catheter-based delivery system. Fifty-five patients were enrol
led, 26 were assigned to Iridium-192 and 29 to the placebo. Follow-up
angiography was obtained in 96% of patients, Restenosis was observed i
n 53.6% of placebo patients compared with only 16.7% of treated patien
ts (P = 0.025). Late luminal loss was also significantly lower in the
Iridium-192 group (0.38 +/- 1.06 mm vs 1.03 +/- 0.97 mm, P = 0.009). C
linical outcome also revealed a significant reduction in the need for
target lesion revascularization in the Iridium-192 group (44.8% vs 11.
5%, P = 0.008). in this preliminary study, catheter-based intracoronar
y radiotherapy substantially reduced the rate of subsequent restenosis
. Clinical trials using gamma emitters, beta emitters, and beta-emitti
ng radioactive stents are ongoing.