Long-Term Safety and Efficacy of Drug-Eluting versus Bare-Metal Stents in Sweden

BACKGROUND: The long-term safety and efficacy of drug-eluting coronary stents have been questioned. METHODS: We evaluated 47,967 patients in Sweden who received a coronary stent and were entered into the Swedish Coronary Angiography and Angioplasty Registry between 2003 and 2006 and for whom complete follow-up data were available for 1 to 5 years (mean, 2.7). In the primary analysis, we compared patients who received one drug-eluting coronary stent (10,294 patients) with those who received one bare-metal stent (18,659), after adjustment for differences in clinical characteristics of the patients and characteristics of the vessels and lesions. RESULTS: Analyses of outcome were based on 2380 deaths and 3198 myocardial infarctions. There was no overall difference between the group that received drug-eluting stents and the group that received bare-metal stents in the combined end point of death or myocardial infarction (relative risk with drug-eluting stents, 0.96; 95% confidence interval CI, 0.89 to 1.03) or the individual end points of death (relative risk, 0.94; 95% CI, 0.85 to 1.05) and myocardial infarction (relative risk, 0.97; 95% CI, 0.88 to 1.06), and there was no significant difference in outcome among subgroups stratified according to the indication for stent implantation. Patients who received drug-eluting stents in 2003 had a significantly higher rate of late events than patients who received bare-metal stents in the same year, but we did not observe any difference in outcome among patients treated in later years. The average rate of restenosis during the first year was 3.0 events per 100 patient-years with drug-eluting stents versus 4.7 with bare-metal stents (adjusted relative risk, 0.43; 95% CI, 0.36 to 0.52); 39 patients would need to be treated with drug-eluting stents to prevent one case of restenosis. Among high-risk patients, the adjusted risk of restenosis was 74% lower with drug-eluting stents than with bare-metal stents, and only 10 lesions would need to be treated to prevent one case of restenosis. CONCLUSIONS: As compared with bare-metal stents, drug-eluting stents are associated with a similar long-term incidence of death or myocardial infarction and provide a clinically important decrease in the rate of restenosis among high-risk patients.