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

Objectives: 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. Background: Long-term efficacy of patients treated with nonpolymeric paclitaxel-eluting stents beyond 1 year has not been well determined. Methods: Patients were randomized to placebo or 1 of 2 doses of paclitaxel (low dose, 1.28 μg/mm²; high dose, 3.10 μg/mm²). Complete after-procedure, 6-month, and 2-year angiographic and IVUS data were available in 53 patients (17, 17, and 19 patients, respectively). Results: 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. Conclusions: 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.