Background: In-stent restenosis (ISR) after bare-metal stent (BMS) implantation is thought to be clinically benign, although this notion remains controversial. The long-term clinical outcomes of ISR with BMS have not been established.
Methods and results: Among 983 consecutive patients (1,227 lesions) implanted with a BMS between 1999 and 2004 at the authors' institution, 746 underwent routine follow-up angiography. Angiographic ISR (ISR group) was evident in 215 patients (28.8%) and 136 of them underwent repeat revascularization. The incidence of major adverse cardiac events (MACE), acute coronary syndrome (ACS), target lesion revascularization and all-cause death were evaluated between patients with and without ISR (non-ISR group). Patients in the ISR group were older and more likely to have diabetes. The median follow-up period was 2,031 days. The rates of MACE and ACS were significantly higher in the ISR group compared with the non-ISR group (33.5% vs. 13.7%, P<0.0001 and 11.2% vs. 7.0%, P<0.05, respectively). Multivariate Cox regression analysis demonstrated that ISR was significantly associated with clinical outcomes (adjusted hazard ratio [HR] for MACE, 2.81; 95% confidence interval [CI]: 2.01-3.94, P<0.01; adjusted HR for ACS, 1.84; 95%CI: 1.08-3.13, P<0.05).
Conclusions: ISR with BMS was significantly associated with long-term adverse clinical outcomes. Risk of future cardiovascular events due to ISR must be carefully considered.