Different edge effects of paclitaxel- and sirolimus-eluting stents on proximal and distal edges in patients with unstable angina： serial intravascular ultrasound analysis

Background It is unclear whether edge segments have different responses to paclitaxel eluting stent （PES） and sirolimus eluting stent （SES） implantation in patients with unstable angina. This study aimed to compare the different vascular edge responses in patients with unstable angina and single de novo coronary lesion treated with SES and PES. Methods Two hundred and fifty-five patients with unstable angina and single de novo lesion were randomly assigned to PES and SES groups. Serial volumetric intravascular ultrasound （IVUS） images were taken immediately after stenting and at an eight-month follow-up. Five-mm edge segments proximal and distal to the stents were analyzed. Results Baseline characteristics were comparable between the two groups. At proximal-edge segment, the vessel area decreased and the plaque area increased significantly in the PES group as compared with the SES group. A significant net loss of lumen area was found in the PES group （from （11.10±3.12） mm^2 at baseline to （9.92±3.59） mm^2 at the follow-up, P 〈0.001）. At the distal-edge segment, the net loss of lumen area in the PES group （from （7.71±2.81） mm^2 at baseline to （6.66±2.29） mm^2 at the follow-up, P 〈0.001） was attributed to a significant increase of plaque area. Proximal-edge stenosis was commonly seen in the PES group （20.0%） as compared with the SES group （5.0%, P=0.001）. This correlated with the higher incidence of target lesion revascularization in the PES group （P=0.03）. Subsegmentally, the smallest A lumen area was located at 2 mm proximally in both groups, at 0 mm distally in the PES group, and at 1 mm distally in the SES group. Conclusions The two groups demonstrated negative remodeling of edge segments. PES was less effective than SES in inhibiting the growth of plaque within the first 1-mm length proximal to the stent.