Frequency, etiology, treatment, and outcomes of drug-eluting stent thrombosis during one year of follow-up.

Drug-eluting stents (DESs) exhibit delayed endothelialization compared with bare metal stents. Adverse late vessel wall remodeling and inflammation have also been attributed to the drug/polymer coating. Recent registry data suggesting increased risk of DES thrombosis in routine clinical practice compared with previous clinical trial experience has led to concerns regarding long-term safety of these devices. We sought to determine the frequency, etiology, and clinical outcomes of stent thrombosis over 1 year in a large patient cohort treated with coronary DESs. Consecutive patients (n = 1,213) who received >or=1 DES between April 2003 and June 2004 at the Mayo Clinic (Rochester, Minnesota) were identified. Medical records pertaining to all deaths, major adverse cardiac events, and/or repeat coronary angiograms after DES placement were evaluated to identify cases of stent thrombosis. Mean follow-up was 12 months. Eleven cases (0.9%, 95% confidence interval 0.4 to 1.3) of stent thrombosis were identified; 4 were acute (<24 hours), 5 were subacute (<30 days), and 2 were late (30 days to 1 year). Normal flow was successfully restored in 7 of 8 cases where this was attempted. There were 10 myocardial infarctions and 2 deaths attributable to stent thrombosis. Eight patients were still alive at 1 year after developing stent thrombosis. In conclusion, early clinical experience with DESs in routine clinical practice indicates a low risk of stent thrombosis, within the range previously reported for bare metal stent thrombosis. Further studies with longer follow-up will be required to definitively address long-term safety concerns.