Sirolimus-releasing stents more effective than vascular brachytherapy for treating restenosis within a stent

David R. Holmes, Jr., M.D., of Mayo Clinic, Rochester, Minn., and colleagues with the SISR trial compared the use of vascular brachytherapy (VBT - intra-coronary radiation therapy) with implantation of the sirolimus-eluting stent for the treatment of restenosis occurring within a previously placed bare-metal stent, in a study appearing in the March 15 issue of JAMA: The Journal of the American Medical Association.

Data on the relative merits of each approach are limited. The study is being released early online to coincide its release with the American College of Cardiology annual conference.

The multicenter trial included 384 patients with in-stent restenosis who were enrolled between February 2003 and July 2004 at 26 academic and community centers. Follow-up continued until June 2005. Patients were randomized to VBT (n = 125) or the sirolimus-eluting stent (n = 259).

Major adverse cardiac events in or out of the hospital were markedly different at 270 days (19.2 percent for the VBT group vs. 10.0 percent for the sirolimus-eluting stent group). The difference in the rate of target lesion revascularization was 19.2 percent in the VBT group vs. 8.5 percent in the sirolimus-eluting stent group. There also was a significant difference in the primary trial end point of target vessel failure (21.6 percent in the VBT group vs. 12.4 percent in the sirolimus-eluting stent group). The angiographic restenosis rate was 29.5 percent for the VBT group vs. 19.8 percent for the sirolimus-eluting stent group. Compared with the VBT group, minimal lumen diameter (size of the opening inside the vessel through which the blood flows) was larger in the sirolimus-eluting stent group at 6-month follow-up.

"In conclusion, in-stent restenosis following bare-metal stent placement remains a significant clinical problem. While vascular brachytherapy remains the only approved therapy for this condition, the results of this study indicate that the sirolimus-eluting stent is superior to vascular brachytherapy at 9 months. Angiographic measurements indicate that while both methods are effective at suppressing neointimal hyperplasia [abnormal increase in cells on vessel wall], the sirolimus-eluting stent yields greater benefits from acute gain due to the stent component of the device and from the absence of edge restenosis. This study suggests that the sirolimus-eluting stent is a safe and effective treatment for in-stent restenosis occurring within bare-metal stents," the authors write.