NEJM: New SCAAR results reassure safety of drug-eluting stents

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Compared with bare-metal stents (BMS), drug-eluting stents (DES) are associated with a similar long-term incidence of death or MI, and provide a clinically important decrease in the rate of restenosis among high-risk patients, according to the latest results from the SCAAR registry published May 7 in the New England Journal of Medicine.

Stefan K. James, MD, PhD, from the department of cardiology at Uppsala University Hospital in Uppsala, Sweden, and colleagues analysed the outcomes of 47,967 patients in Sweden, who received a coronary stent and were entered into the Swedish Coronary Angiography and Angioplasty Registry (SCAAR) between 2003 and 2006. The complete follow-up data were available for one to five years.

In the primary analysis, the researchers compared patients who received one DES (10,294 patients) with those who received one BMS (18,659), after adjustment for differences in clinical characteristics of the patients and characteristics of the vessels and lesions.

James and colleagues based their outcome analyses on 2,380 deaths and 3,198 MIs. They found that their was no overall difference between the group that received DES and the group that received BMS in the combined end point of death or MI, or the individual end points of death and MI and there was no significant difference in outcome among subgroups stratified according to the indication for stent implantation.

The researchers reported that patients who received DES in 2003 had a significantly higher rate of late events than BMS patients in the same year, but they did not observe any difference in outcome among patients treated in later years. The average rate of restenosis during the first year was three events per 100 patient-years with DES versus 4.7 with BMS; 39 patients would need to be treated with DES to prevent one case of restenosis.

Among high-risk patients, the authors reported that the adjusted risk of restenosis was 74 percent lower with DES than with BMS, and only 10 lesions would need to be treated to prevent one case of restenosis.

Commenting on the results, the European Society of Cardiology (ESC) spokesperson Franz Eberli, MD, interventionalist cardiologist from the University Hospital Zurich in Switzerland, said that these newest SCAAR findings, "with the results extended to include all patients in Sweden receiving a stent between 2003 and 2006, found no increased risk of death between the two groups...The latest SCAAR data provides a lot of reassurance on the safety of DES," adding that the study was probably the largest registry yet on stents with the longest follow-up.

However, Steen Dalby Kristensen, MD, from Aarhus University Hospital in Denmark, and vice president of the ESC, highlighted the inherent problems of registries, where there are dangers of inclusion bias. "To draw definitive conclusions about the safety of drug eluting stents, what is really needed, is a large scale randomised controlled long term trial," he said. "Unfortunately there are challenges in getting public funding for such trials, which may also prove difficult to perform in countries that already have high uptakes of DES."

He added that data from the SCAAR registry suggesting that 39 patients would need to be treated with DES to prevent one case of restenosis, and that 10 patients in the higher risk groups would need to be treated to prevent one case, made a strong argument of the cost effectiveness of DES. "What also needs to be remembered is that preventing restenosis also has an enormous influence on the patient's quality of life," he said.