BACKGROUND: Increased rates of late stent thrombosis after first-generation drug eluting stents have prompted concerns about its long-term safety. Local vascular inflammation and delayed healing have been identified as important substrates. Persistent polymer, anti-proliferative drug, or both, have been identified as important etiological factors. In the present study we sought to investigate the performance and efficacy of the novel polymer-free Amazonia-PAX paclitaxel-eluting stent against the first-generation, polymer-based Taxus Liberté paclitaxel-eluting stent. METHODS: PAX-A is a prospective, randomized, single-blinded, single-center study, in which patients with single de novo, < 20 mm lesions, in native coronaries of 2.5 mm to 3.5 mm diameter were randomized to receive the Amazonia-PAX stent (n = 16) or the Taxus Liberté stent (n = 15). Primary end-points were in-stent late luminal loss by QCA and in-stent % obstruction volume by intravascular ultrasound (IVUS) at 4-month follow-up. Secondary end-points included binary restenosis and changes in vessel, lumen and stent volume detected by IVUS at the 4-month follow-up, as well as major adverse cardiac events [MACE: death, non-fatal myocardial infarction (MI) and target lesion revascularization (TLR)] at one year. RESULTS: No differences were observed in the baseline clinical and angiographic characteristics. At the 4-month follow-up in-stent late luminal loss (0.77 [0.47-1.05] mm vs. 0.42 [0.17-0.86] mm; P = 0.29) and in-stent % obstruction volume (19.2 + 9.5% vs. 9.3 + 10.1%; P = 0.08) were higher in the Amazonia-PAX stent. At 1 year, MACE rate was 18.7% in the Amazonia-PAX group and 26.7% in the Taxus Liberté group (P = 0.8). One death and two non-fatal MIs were detected in the Taxus Liberté and Amazonia-PAX groups, respectively. Two patients in the Amazonia-PAX and 4 patients in the Taxus Liberté required TLR. CONCLUSIONS: The polymer-free Amazonia-PAX paclitaxel-eluting stent promoted a moderate intimal hyperplasia inhibition as compared to the first-generation polymer-based paclitaxel-eluting stent Taxus Liberté.
Drug-eluting stents; Paclitaxel; Coronary restenosis; Coronary thrombosis
