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Cordis (Miami Lakes, Florida) reported that the Cypher sirolimus-eluting coronary stent reduced the risk of target-vessel failure (TVF) by almost half in patients who suffered acute myocardial infarction (AMI), compared to those treated with balloon angioplasty and a bare-metal stent (BMS), according to data appearing recently in the New England Journal of Medicine.

At one year post-implantation, the study found that patients given the Cypher stent were 49% less likely to experience TVF than those given a BMS. Patients in the Cypher stent arm had a TVF rate of 7.3% compared to 14.3% in the BMS arm of the study (p<0.004). TVF is a composite of the need for re-treatment (target vessel revascularization or TVR), recurrent heart attack and death due to cardiac reasons. The overall mortality rate in both the Cypher stent arm of the trial and the BMS group was the same, 2.2%.

The data were originally presented at the American College of Cardiology annual scientific session in March. TYPHOON (the trial to assess the use of the Cypher Stent in AMI treated with balloon angioplasty), sponsored by Cordis, is the first to study the safety and efficacy of the Cypher stent in patients who have suffered an AMI, the company said. Data were reported on 712 patients who had suffered an AMI within 12 hours before the stent placement. TYPHOON was conducted at 48 sites across Europe, Israel and Australia.

An angiographic sub-study was conducted in 210 patients who participated in TYPHOON to assess the rate of restenosis and the amount of tissue proliferation (late loss) within the stent eight months after receiving either a Cypher stent or the BMS control. The study found that the Cypher stent was associated with an 83% reduction in re-blockage rates and an 83% reduction in late loss. Specifically, patients in the Cypher had an in-stent restenosis rate of 3.5%, compared to 20.3% in the BMS arm (p=0.0010) and an average late loss of 0.14 mm compared to 0.83 mm in the BMS arm (p<0.0001.).

Since patients receiving bare-metal stents for the treatment of heart attacks are at increased risk of stent thrombosis, there was initial concern about the use of a drug-eluting stent in this patient population. Through one-year follow-up in the TYPHOON trial, the stent thrombosis rates with the Cypher Stent (3.4%) and the bare-metal stent (3.6%) arms of the study were comparable (12 events in the Cypher group vs. 13 events in the group treated with BMS).

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