Polymer-free versus biodegradable-polymer drug-eluting stent in patients undergoing percutaneous coronary intervention: an assessor-blind, non-inferiority, randomised controlled trial

BACKGROUND: Few data are available on polymer-free drug-eluting stents in patients undergoing percutaneous coronary intervention (PCI). AIMS: We aimed to determine the efficacy and safety of a polymer-free amphilimus-eluting stent (AES), using a reservoir-based technology for drug delivery, compared with a biodegradable-polymer everolimus-eluting stent (EES). METHODS: This was a randomised, investigator-initiated, assessor-blind, non-inferiority trial conducted at 14 hospitals in Italy (ClinicalTrials.gov: NCT04135989). All-comer patients undergoing PCI were randomly assigned to either polymer-free AES or biodegradable-polymer EES. The primary endpoint was a device-oriented composite endpoint, including cardiovascular death, target vessel myocardial infarction, or target lesion revascularisation at 1-year follow-up. RESULTS: Between January 2020 and June 2022, a total of 2,107 patients with 3,042 coronary lesions were randomised to polymer-free AES (1,051 patients) or biodegradable-polymer EES (1,056 patients). At 1-year follow-up, the primary endpoint occurred in 86 (8.2%) patients randomised to polymer-free AES and 76 (7.2%) patients randomised to biodegradable-polymer EES (risk difference 1%, upper limit of the 1-sided 95% confidence interval [CI] of 2.9%; p for non-inferiority=0.041). There were no significant differences in the incidence of the components of the primary endpoint between groups. However, definite or probable stent thrombosis occurred more frequently in patients randomised to polymer-free stents (1.0% vs 0.3%; hazard ratio 3.72, 95% CI: 1.04-13.33; p=0.044) due to an increased risk of early stent thrombosis within 30 days. CONCLUSIONS: In all-comer patients undergoing PCI, polymer-free AES were non-inferior to biodegradable-polymer EES at 1-year follow-up in terms of a device-oriented composite endpoint despite being associated with an increased risk of early stent thrombosis.