Objectives Peri-stent vascular responses to DES have been incompletely understood with different DESs. Serial intravascular ultrasound was used to study chronic arterial responses and edge effects after implantation of Sirolimus-eluting stent (SES) or Paclitaxel-eluting stent (PES). Methods Two hundred-two angina patients (123 men; 61.5짹9.2 years of age) were assigned to SES (n=91) or PES (n=111) implantation. Intravascular ultrasound of 5-mm long segments immediately proximal and distal to the stent was performed to determine volume and area of Vessel, Plaque, Lumen after the procedure and at the 9-month follow-up. The change (��) of each parameters between postprocedure and follow-up was calculated Results In proximal reference segment, the �� Vessel, �� Plaque and �� Lumen volume were not different between two groups. The �� Plaque volume, however, increased more in PES than SES in distal reference segment (6.6짹15.7 vs 1.0짹13.1 mm³, P=.016). In proximal 1mm and distal 1mm reference segments, mean Lumen area decreased because of negative remodeling (proximal, 9.9짹2.4 to 9.4짹2.6 mm², P=.004; distal, 7.6짹2.4 to 7.2짹2.4 mm², P=.052) with plaque progression (proximal, 1.9짹1.5 to 2.2짹2.0 mm², P=.095; distal, 0.6짹1.1 to 1.0짹1.4 mm², P=.018) in the PES group. Conversely, mean Lumen area increased because of plaque regression (proximal, 3.2짹1.8 to 2.1짹1.6 mm², P=.000; distal, 1.5짹1.4 to 0.9짹1.3 mm², P=.000) even though there was negative remodeling in the SES group (proximal, 10.1짹2.4 to 9.6짹2.3 mm², P=.019; distal, 7.8짹2.3 to 7.5짹2.3 mm², P=.074). The �� Plaque and �� Lumen at proximal and distal reference segment were more prominent in the PES group than the SES group (table). Conclusions The PES implantation was associated with luminal reduction accompanied by negative remodeling with plaque progression. These findings, however, were not noted in the SES group.