Impact of sirolimus-eluting stent implantation compared to bare-metal stent implantation for acute myocardial infarction on coronary plaque composition at nine months follow-up: a Virtual Histology intravascular ultrasound analysis. Results from the Leiden MISSION! intervention study

Aims: To evaluate effects of sirolimus-eluting stents (SES) compared to bare-metal stents (BMS) at stent edges in patients with acute myocardial infarction (AMI). Methods and results: Clinical, angiographic, intravascular ultrasound (IVUS) and virtual histology (VH)-IVUS results were obtained and analysed in 20 SES and 20 BMS AMI patients at the index procedure and at nine months follow-up. Quantitative angiography and IVUS showed a trend toward decreases in mean lumen diameter, vessel volume, minimum lumen area and mean lumen area at both stent edges of BMS, and at the proximal edge of SES. At the distal stent edge, a significant difference between BMS and SES treated patients in mean lumen area was found (Delta-0.8 +/- 1.6 mm(2) versus Delta 0.2 +/- 0.8 mm(2) respectively, p=0.04). Furthermore, in-stent SES had a larger lumen volume (SES: 167.7 +/- 59.2 mm(3) versus BMS: 125.1 +/- 43.8 mm(3); p=0.02) and less neointima volume (7.3 +/- 9.1 mm(3) versus 53.2 +/- 35.1 mm(3); p<0.001). Neither SES nor BMS demonstrated a significant effect on plaque composition at follow-up VH-IVUS analysis. Conclusions: A significant difference between SES and BMS treated patients was observed with respect to mean lumen diameter distal to the stented segment which suggests a downstream effect of sirolimus elution.