Two-year follow-up of the quantitative angiographic and volumetric intravascular ultrasound analysis after nonpolymeric paclitaxel-eluting stent implantation: late "catch-up" phenomenon from ASPECT Study.

Abstract

This study used serial angiographic and intravascular ultrasound (IVUS) analysis to evaluate the long-term efficacy of a nonpolymeric, paclitaxel-eluting stent coating on intimal hyperplasia (IH) 2 years after implantation. Long-term efficacy of patients treated with nonpolymeric paclitaxel-eluting stents beyond 1 year has not been well determined. Patients were randomized to placebo or 1 of 2 doses of paclitaxel (low dose, 1.28 microg/mm2; high dose, 3.10 microg/mm2). Complete after-procedure, 6-month, and 2-year angiographic and IVUS data were available in 53 patients (17, 17, and 19 patients, respectively). Baseline characteristics were similar among the 3 groups. Although 6-month minimal luminal diameter (MLD) was significantly smaller in placebo compared with paclitaxel-eluting stent patients (1.9 +/- 0.6 mm in placebo, 2.5 +/- 0.6 mm in low-dose, and 2.6 +/- 0.5 mm in high-dose patients, p = 0.004), the MLDs at 2 years were similar (2.3 +/- 0.6 mm, 2.3 +/- 0.7 mm, and 2.0 +/- 0.8 mm, respectively, p = 0.4). Despite a stepwise reduction in IH accumulation at 6 months (23 +/- 18 mm3 in placebo, 14 +/- 11 mm3 in low-dose, and 10 +/- 12 mm3 in high-dose, p = 0.017), the increase of IH volume from 6 months to 2 years was significantly greater in the high-dose patients (13 +/- 14 mm3 in high-dose vs. 4 +/- 7 mm3 in low-dose patients, p = 0.074; and vs. 1 +/- 13 mm3 in placebo, p = 0.019). Late target lesion revascularization (beyond 1 year) was performed in 2 high-dose patients. Despite the suppression of IH after non-polymeric paclitaxel-eluting stents compared with bare-metal stents at 6 months, a "late catch-up" IH growth was found in the high-dose patients at 2-year follow-up.