Sirolimus-eluting stents versus bare-metal stents in patients with ST-segment elevation myocardial infarction: 9-month angiographic and intravascular ultrasound results and 12-month clinical outcome results from the MISSION! Intervention Study.

Objectives: Our purpose was to evaluate the efficacy and safety of drug-eluting stents in the setting of primary percutaneous coronary intervention for ST-segment elevation myocardial infarction (STEMI).

Background: There is inconsistent and limited evidence about the efficacy and safety of drug-eluting stents in STEMI patients.

Methods: A single-blind, single-center, randomized study was performed to compare bare-metal stents (BMS) with sirolimus-eluting stents (SES) in 310 STEMI patients. The primary end point was in-segment late luminal loss (LLL) at 9 months. Secondary end points included late stent malapposition (LSM) at 9 months as determined by intravascular ultrasound imaging and clinical events at 12 months.

Results: In-segment LLL was 0.68 +/- 0.57 mm in the BMS group and 0.12 +/- 0.43 mm in the SES group with a mean difference of 0.56 mm, 95% confidence interval 0.43 to 0.68 mm (p < 0.001). Late stent malapposition at 9 months was present in 12.5% BMS patients and in 37.5% SES patients (p < 0.001). Event-free survival at 12 months was 73.6% in BMS patients and 86.0% in SES patients (p = 0.01). The target-vessel-failure-free survival was 84.7% in the BMS group and 93.0% in the SES group (p = 0.02), mainly because of a higher target lesion revascularization rate in BMS patients (11.3% vs. 3.2%; p = 0.006). Rates of death, myocardial infarction, and stent thrombosis were not different.

Conclusions: Sirolimus-eluting stent implantation in STEMI patients is associated with a favorable midterm clinical and angiographic outcome compared with treatment with BMS. However, LSM raises concern about the long-term safety of SES in STEMI patients.