Two-Year Follow-Up After Catheter-Based Radiotherapy to Inhibit Coronary Restenosis

Abstract

Background —Although early trials indicate the treatment of restenosis with radiation therapy is safe and effective, the long-term impact of this new technology has been questioned. The possibility of late untoward consequences, such as aneurysm formation, perforation, and accelerated vascular disease, is of significant concern. Furthermore, it is not known whether the beneficial effects of radiation therapy will be durable or whether radiation will only delay restenosis. Methods and Results —A double-blind, randomized trial was undertaken to compare 192 Ir with placebo sources in patients with previous restenosis after coronary angioplasty. Patients were randomly assigned to receive a 0.76-mm (0.03-in) ribbon containing sealed sources of either 192 Ir or placebo. All patients underwent repeat coronary angiography at 6 months. All living patients were contacted 24 months after their index study procedure. Patients were assessed with respect to the need for target-lesion revascularization or nontarget-lesion revascularization, occurrence of myocardial infarction, or death. Over a 9-month period, 55 patients were enrolled; 26 were randomized to 192 Ir and 29 to placebo. Follow-up was obtained in 100% of living patients at a minimum of 24 months. Target-lesion revascularization was significantly lower in the 192 Ir group (15.4% versus 44.8%; P <0.01). Nontarget-lesion revascularization was similar in 192 Ir and placebo patients (19.2% versus 20.7%; P =NS). There were 2 deaths in each group. The composite end point of death, myocardial infarction, or target-lesion revascularization was significantly lower in 192 Ir-treated versus placebo-treated patients (23.1% versus 51.7%; P =0.03). No patient in the 192 Ir group sustained a target-lesion revascularization later than 10 months. Conclusions —At 2-year clinical follow-up, treatment with 192 Ir demonstrates significant clinical benefit. Although further follow-up (including late angiography) will be necessary, no clinical events have occurred to date in the 192 Ir group to suggest major untoward effects of vascular radiotherapy. At the intermediate follow-up time point, vascular radiotherapy continues to be a promising new treatment for restenosis.