Stent :: Swedish registry results of drug-eluting stents

Boston Scientific Corporation (NYSE: BSX) today commented on results from a Swedish registry assessing the long-term outcomes of drug-eluting stents (DES) versus bare- metal stents (BMS) that were released online today and are scheduled for publication in the March 8th edition of the New England Journal of Medicine.

“The Swedish registry data are provocative, but far from definitive,” said Donald S. Baim, M.D., Chief Medical and Scientific Officer for Boston Scientific. “The raw data showed no increase in death or heart attack for drug-eluting stents, and a small increase was suggested only after statistical adjustment was performed in an effort to correct for the significantly greater number of high-risk patients in the drug-eluting stent group. In addition, the counting of adverse events was restarted beyond the first six months, after drug-eluting stents have already provided their greatest benefit.”

Writing in an accompanying Perspective piece in the March 8th edition, Dr. William H. Maisel, M.D., M.P.H, and the chairman of the December 7-8 U.S. Food and Drug Administration (FDA) advisory panel meeting on DES, made the following comment about the Swedish registry: “Stent selection, however, was not randomized among registry patients, so the observed differences may be due to confounding factors such as physician bias in stent preference. Thus, current data are inadequate for assessment of the relative benefit of off- label use of drug-eluting stents as compared with either bare-metal stents or coronary-artery bypass surgery.”

The registry was designed as a non-randomized, observational assessment combining the Swedish Coronary Angiography and Angioplasty Registry (SCAAR) with other national health outcome databases, to track the outcomes of nearly 20,000 patients receiving DES or BMS in 2003 and 2004. The authors report similar rates for the composite primary endpoint of death and myocardial infarction (MI, or heart attack) in DES and BMS patients over a median follow- up of 1.5 years and a maximum follow-up of three years after stent implantation.

The Swedish registry findings are consistent with results from numerous recently published studies in Europe and the U.S. that show superior efficacy (a reduced need for revascularization) and comparable safety (no net increase in death or myocardial infarction) for DES relative to BMS. Those studies include the Dutch TSEARCH/RESEARCH registry with more than 2,500 patients(1), the Swiss BASKET study(2) with more than 800 patients, the Italian REAL registry with more than 1,600 patients(3), the U.S. DEScover registry with nearly 7,000 patients(4), and the recently published randomized clinical trial meta-analysis by a study group at the Basel Institute for Clinical Epidemiology(5) in Switzerland, with more than 8,000 patients. The U.S. Wake Forest registry with nearly 2,500 patients(6) actually reported a statistically significant lower death and myocardial infarction rate for DES when compared to BMS.

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