IRON bioresorbable scaffold demonstrated noninferior angiographic and clinical outcomes compared with a contemporary metallic drug eluting stent at 2 years in patients with coronary artery disease, according to findings from the IRONMAN II randomised trial.
Iron Bioresorbable Scaffold in Randomised Evaluation
The prospective, multicentre, single blinded, noninferiority trial enrolled 518 patients with myocardial ischaemia and one or two de novo target lesions across 36 centres in China between 10 March and 13 December 2022. Participants were randomly assigned in a 1:1 ratio to receive a thin strut sirolimus eluting iron bioresorbable scaffold or a cobalt chromium everolimus eluting stent.
Clinical follow up was scheduled at 1 month, 6 months, and 12 months, and annually to 5 years. Angiographic and optical coherence tomography follow up were planned at 2 years. The primary endpoint was 2 years in segment late lumen loss.
At 2 years, lesion level in segment late lumen loss was 0.28 mm with the iron bioresorbable scaffold and 0.23 mm with the cobalt chromium everolimus eluting stent: difference: 0.08 mm; 95% CI: −0.02–0.18; Pnoninferiority=0.03. Data met criteria for noninferiority.
Functional And Imaging Outcomes
Secondary powered endpoints included quantitative flow ratio and optical coherence tomography derived cross sectional mean flow area. Mean quantitative flow ratio was 0.90 with the iron bioresorbable scaffold and 0.92 with the metallic stent: difference: −0.02; 95% CI: −0.04–0; Pnoninferiority=0.05. Mean optical coherence tomography flow area was 6.92 mm² versus 6.64 mm²: difference: 0.27; 95% CI: −0.09–0.63; Pnoninferiority<0.0001.
Target lesion failure at 2 years occurred in 7.4% of patients receiving the iron bioresorbable scaffold and 5.4% of those treated with the metallic stent: hazard ratio: 1.37; 95% CI: 0.69–2.73; P=0.37. No significant between group differences were observed in the patient oriented composite endpoint, death, or myocardial infarction.
Safety And Revascularisation
No scaffold thromboses were reported in the iron bioresorbable scaffold group, whereas one stent thrombosis occurred in the comparator arm. Binary restenosis and revascularisation rates were higher with the iron bioresorbable scaffold; however, most events were not driven by ischaemia.
The investigators concluded that while longer term follow up is required to determine whether late benefits emerge after complete resorption, the iron bioresorbable scaffold provides comparable 2-year performance to a contemporary drug eluting stent in patients with coronary artery disease.
Reference
Gao R et al. Sirolimus-eluting iron bioresorbable scaffolds vs everolimus-eluting stents for percutaneous coronary intervention: a randomized trial (IRONMAN II). JACC. 2026;https://doi.org/10.1016/j.jacc.2025.12.024.
