Peristent Remodeling and Neointimal Suppression 2 Years After Polymer-Based, Paclitaxel-Eluting Stent Implantation: Insights From Serial Intravascular Ultrasound Analysis in the TAXUS II Study

Background— The purpose of this study was to evaluate long-term vascular responses as long as 2 years after implantation of polymer-based, paclitaxel-eluting stents in contrast to uncoated stents. Methods and Results— TAXUS II is a randomized, double-blind trial comparing slow-release (SR) and moderate-release (MR) TAXUS stents with bare-metal control stents (BMSs). One hundred sixty-one event-free patients (SR, 43; MR, 41; and BMS, 77) underwent serial intravascular ultrasound (IVUS) analysis after the procedure and at 6 months and 2 years. At 2 years, neointimal responses continued to be significantly suppressed in the SR and MR groups when compared with the BMS group (BMS, 1.49±1.12 mm2; SR, 0.94±0.76 mm2 [P=0.004]; and MR, 1.06±0.90 mm2 [P=0.02]). Between 6 months and 2 years, the BMS group showed compaction of the neointima (&Dgr;, −0.22±1.05 mm2 [P=0.08]). In contrast, both the SR and MR groups exhibited an increase (&Dgr; SR, 0.30±0.76 mm2 (P=0.01); MR, 0.41±0.94 mm2 [P=0.009]). Between 6 months and 2 years, the initial increase in plaque outside the stent regressed in the BMS and SR groups to levels comparable to those after the procedure, whereas expansive remodeling partially regressed in the MR group (&Dgr; between after the procedure and 2 years BMS, −0.34±1.28 mm2 [P=0.05]; SR, −0.02±1.40 mm2 [P=0.93]; MR, 0.32±1.56 mm2 [P=0.27]). Conclusions— The 2-year follow-up demonstrates that neointimal suppression was dose independent and that this effect was still sustained at 2 years. However, the increase in area outside the stent seen at 6 months regressed to different extents in a dose-dependent manner at 2 years.