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Will Sirolimus-Eluting Stents Consign Bare Metal to History?

In patients with complex coronary lesions, the rate of repeat target-lesion revascularization was lower with drug-eluting stents than with bare-metal stents.

Stents that are coated with sirolimus, an immunosuppressive agent that inhibits proliferation of vascular smooth-muscle cells, are associated with lower restenosis rates after percutaneous coronary intervention than are bare-metal stents. Published comparisons have focused primarily on nondiabetic patients with relatively simple coronary lesions. Now, in 2 multicenter, double-blind, randomized trials, supported by a sirolimus-stent manufacturer, researchers have compared these stents with bare-metal (control) stents in more challenging patients, about 25% of whom had diabetes.

A U.S. trial involved 1058 patients. The incidence of major adverse cardiac events (death from cardiac causes, myocardial infarction, or repeat target-lesion revascularization [TLR]) in the first 9 months was significantly lower in the sirolimus group (7%) than in the control group (19%), driven mostly by a difference in repeat TLR. The rate of in-segment restenosis, which was assessed by coronary angiography at 8 months, was significantly lower in the sirolimus group than in the control group (9% vs. 36%), including in the subset of patients with diabetes (18% vs. 51%).

A European trial involved 352 patients. The incidence of major adverse cardiac events at 9 months was significantly lower in the sirolimus group (8%) than in the control group (23%), again driven by a difference in TLR. The rate of in-segment restenosis at 8 months also was significantly lower in the sirolimus group than in the control group (6% vs. 42%).

Stent-thrombosis rates did not differ significantly between the sirolimus and control groups in either study. On October 29, 2003, the FDA issued a public health notification regarding subacute thromboses and possible hypersensitivity reactions among some recipients of the sirolimus-eluting stent that was used in these studies. However, the FDA notes that it cannot determine yet whether the event rates are different from those experienced by patients who receive bare-metal stents.

Comment: Sirolimus-eluting stents now are FDA-approved for initial use in diseased native coronary arteries, where they appear to reduce short-term restenosis rates substantially. In the current studies, overall restenosis rates fell to single digits in sirolimus-stent recipients, despite complex lesions and a high prevalence of diabetes. However, important issues remain: For example, restenosis rates in diabetic patients, although reduced by sirolimus stents, remain suboptimal. Although long-term results with the new stents still are lacking, we should have additional answers as these stents quickly come into widespread clinical use.

— Kirsten E. Fleischmann, MD, MPH

Published in Journal Watch General Medicine November 4, 2003

Citation(s):

Moses JW et al. Sirolimus-eluting stents versus standard stents in patients with stenosis in a native coronary artery. N Engl J Med 2003 Oct 2; 349:1315-23.

• Original article (Subscription may be required)
• Medline abstract (Free)

Schofer J et al. Sirolimus-eluting stents for treatment of patients with long atherosclerotic lesions in small coronary arteries: Double-blind, randomised controlled trial (E-SIRIUS). Lancet 2003 Oct 4; 362:1093-9.

• Medline abstract (Free)

Marks AR. Sirolimus for the prevention of in-stent restenosis in a coronary artery. N Engl J Med 2003 Oct 2; 349:1307-9.

• Original article (Subscription may be required)
• Medline abstract (Free)

Sigwart U. Drug-delivering coronary artery stents: Bare metal threatened by extinction? Lancet 2003 Oct 4; 362:1088-9.

• Medline abstract (Free)