Vascular Responses at Proximal and Distal Edges of Paclitaxel-Eluting Stents

Abstract

Background— On the basis of brachytherapy experience, edge stenosis has been raised as a potential limitation for drug-eluting stents. We used serial intravascular ultrasound (IVUS) to prospectively analyze vessel responses in adjacent reference segments after implantation of polymer-controlled paclitaxel-eluting stents. Methods and Results— TAXUS II was a randomized, double-blind trial with 2 consecutive patient cohorts that compared slow-release (SR) and moderate-release (MR) paclitaxel-eluting stents with control bare metal stents (BMS). By protocol, all patients had postprocedure and 6-month follow-up IVUS. Quantitative IVUS analysis was performed by an independent core laboratory, blinded to treatment allocation, in 5-mm vessel segments immediately proximal and distal to the stent. Serial IVUS was available for 106 SR, 107 MR, and 214 BMS patients. For all 3 groups, a significant decrease in proximal-edge lumen area was observed at 6 months. The decrease was comparable (by ANOVA, P =0.194) for patients in the SR (−0.54±2.1 mm 2 ) and MR (−0.88±1.9 mm 2 ) groups compared with the BMS (−1.02±1.9 mm 2 ) group. For the distal edge, a significant decrease in lumen area was only observed with BMS (−0.91±2.0 mm 2 , P <0.0001); this decrease was significantly attenuated with SR (0.08±2.0 mm 2 ) and MR (−0.19±1.7 mm 2 ) stents ( P <0.0001 by ANOVA). Negative vessel remodeling was observed at the proximal (−0.48±2.2 mm 2 , P =0.011) but not the distal edges of BMS and at neither edge of SR or MR stents. Conclusions— The marked reduction in in-stent restenosis with SR or MR stents is not associated with increased edge stenosis at 6-month follow-up IVUS. In fact, compared with BMS, there is instead a significant reduction in late lumen loss at the distal edge with TAXUS stents.