The SCRIPPS Trial
The SCRIPPS trial is a randomized, double-blind, placebo-controlled trial evaluating the impact of gamma radiation to inhibit in-stent restenosis. Fifty-five patients were enrolled; twenty-six were assigned to receive catheter-based radiation with Ir-192 and 29 were treated with placebo. Angiographic restenosis in the Ir-192-treated patients was significantly reduced at six months (17% vs. 54%; p = 0.01), with the results sustained at 3-year follow-up (33.3% vs. 63.6%; p < 0.05). Likewise, the composite clinical endpoint of death, myocardial infarction or target lesion revascularization was also commensurately lower in the treated group as compared to the placebo group (23.1% vs. 55.2%; p = 0.01). Late angiography revealed no perforation, aneurysm or pseudoaneurysm or special safety issues unique to radiotherapy.

The Achilles heel of coronary angioplasty continues to be the need for repeat procedures. Coronary stents reduce restenosis by 30% by providing a luminal scaffold that eliminates classic recoil and remodeling. Stents, however, increase the proliferative component of restenosis. In several animal models of restenosis, local, catheter-based ionizing radiation or radioactive stents have demonstrated significantly reduced neo-intimal proliferation. This initiated the Scripps coronary radiation to inhibit proliferation post-stenting (SCRIPPS) trial, as a double-blind, placebo-controlled, randomized trial to test this new modality in restenotic stented human coronary arteries.