CATHETER-BASED RADIOTHERAPY TO INHIBIT RESTENOSIS AFTER CORONARY STENTING

Background In animal models of coronary restenosis, intracoronary radi otherapy has been shown to reduce the intimal hyperplasia that is a pa rt of restenosis. We studied the safety and efficacy of catheter-based intracoronary gamma radiation plus stenting to reduce coronary resten osis in patients with previous restenosis. Methods Patients with reste nosis underwent coronary stenting, as required, and balloon dilation a nd were then randomly assigned to receive catheter-based irradiation w ith iridium-192 or placebo. Clinical follow-up was performed, with qua ntitative coronary angiographic and intravascular ultrasonographic mea surements at six months. Results Fifty-five patients were enrolled; 26 were assigned to the iridium-192 group and 29 to the placebo group. A ngiographic studies were performed in 53 patients (96 percent) at a me an (+/-SD) of 6.7+/-2.2 months. The mean minimal luminal diameter at f ollow-up was larger in the iridium-192 group than in the placebo group (2.43+/-0.78 mm vs. 1.85+/-0.89 mm, P=0.02). Late luminal loss was si gnificantly lower in the iridium-192 group than in the placebo group ( 0.38+/-1.06 mm vs. 1.03+/-0.97 mm, P=0.03). Angiographically identifie d restenosis (stenosis of 50 percent or more of the luminal diameter a t follow-up) occurred in 17 percent of the patients in the iridium-192 group, as compared with 54 percent of those in the placebo group (P=0 .01). There were no apparent complications of the treatment. Conclusio ns In this preliminary, short-term study of patients with previous cor onary restenosis, coronary stenting followed by catheter-based intraco ronary radiotherapy substantially reduced the rate of subsequent reste nosis. (C) 1997, Massachusetts Medical Society.