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Sirolimus-eluting iron bioresorbable scaffold shows higher late lumen loss than everolimus-eluting stents in coronary artery disease patientsNew iron scaffold matches metal stents for heart artery repair

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Key Takeaway
Note higher late lumen loss and target lesion failure with sirolimus-eluting iron bioresorbable scaffold compared to everolimus-eluting stents.

This randomized trial evaluated patients with myocardial ischemia and 1 or 2 de novo target lesions across 36 centers in China. The study compared a sirolimus-eluting iron bioresorbable scaffold (IBS) against everolimus-eluting stents (CoCr-EES). The sample size included 518 participants who underwent angiographic and OCT follow-up at 1, 6, and 12 months, with annual assessments continuing to 5 years.

Primary results focused on 2-year angiographic in-segment late lumen loss (LLL). The IBS group showed a mean LLL of 0.28 (0.52) mm, while the CoCr-EES group showed 0.23 (0.43) mm. The difference was 0.08 mm with a 95% CI of -0.02 to 0.18 and a P value of 0.03. Secondary outcomes included mean QFR of 0.90 (0.13) for IBS versus 0.92 (0.09) for CoCr-EES, and mean OCT flow area of 6.92 (3.48) mm versus 6.64 (2.44) mm, respectively.

Safety analysis indicated no significant between-group differences in the rates of patient-oriented composite endpoint, death, or myocardial infarction. No scaffold thromboses occurred in the IBS group, whereas 1 stent thrombosis occurred with CoCr-EES. However, two-year target lesion failure was 7.4% for IBS patients versus 5.4% for CoCr-EES patients, with a hazard ratio of 1.37 and a P value of 0.37.

Key limitations note that longer-term follow-up is necessary to determine whether late benefits are realized after complete IBS resorption. Non-ischemia-driven revascularization rates were higher after IBS, a detail that requires careful interpretation when assessing clinical utility.

Imagine a heart surgeon placing a tiny tube inside a blocked artery. For decades, that tube stayed there forever. Now, a new option might disappear completely after doing its job. This change could feel huge for anyone worried about permanent metal inside their body.

Millions of people suffer from coronary artery disease every year. Their arteries narrow and block blood flow to the heart muscle. Doctors usually place metal stents to keep these tubes open. These stents never go away. Some patients worry about long-term risks from the metal. Others want a device that heals with them instead of staying as a foreign object.

The Old Way Vs New Way

For years, doctors relied on metal stents made of cobalt chromium. These work well but remain in the body forever. The new option is an iron scaffold coated with a drug called sirolimus. This drug helps prevent scar tissue from growing back inside the artery. The twist is that the iron scaffold is designed to dissolve slowly over time.

A Factory That Self-Destructs

Think of the iron scaffold like a temporary factory built inside your artery. It opens up the blocked path and stops scarring. Once the job is done, the factory shuts down and disappears. This is different from a permanent metal pipe. The iron turns into harmless rust that the body naturally removes. This process is called resorption.

Researchers tested this new iron scaffold against standard metal stents in a large trial. They studied 518 patients across 36 centers in China. Half received the iron scaffold and half received the metal stent. The team checked the arteries after two years to see how well they stayed open.

The results showed the iron scaffold performed just as well as the metal stent. The arteries stayed open in both groups. There were no major differences in heart attacks or deaths between the two groups. One metal stent did clot, but no iron scaffolds did. This suggests the iron material is safe.

This doesn't mean this treatment is available yet.

Experts say this trial is a major step forward. The iron scaffold proved noninferior to the metal stent. This means it is at least as good as the current standard. However, the team noted some differences in how often patients needed another procedure. Most of those extra procedures were not driven by heart problems.

If you have a blocked artery, talk to your doctor about all options. This new scaffold might be an option for you in the future. It could reduce the need for permanent metal inside your body. You should ask if this device is available in your area. Doctors will decide if it fits your specific health needs.

This study had some limits. The iron scaffold fully dissolves over several years. The team only followed patients for two years so far. They need more time to see if the benefits last after the device disappears. Also, the trial happened mostly in China. Results might differ in other populations.

More research is needed before this becomes a common choice. Doctors will run larger trials to confirm these findings. Regulatory agencies must approve the device before hospitals can use it widely. Patients should expect a few more years before this option is standard care. The journey from trial to clinic takes time and careful review.

Study Details

Study typeRct
Sample sizen = 259
EvidenceLevel 2
Follow-up12.0 mo
PublishedApr 2026
View Original Abstract ↓
BACKGROUND: The novel thin-strut sirolimus-eluting iron bioresorbable scaffold (IBS) demonstrated safety and efficacy in a nonrandomized first-in-human study. OBJECTIVES: The objective of this study was to compare the IBS with contemporary metallic cobalt chromium everolimus-eluting stents (CoCr-EES) in patients with coronary artery disease. METHODS: IRONMAN-II was a prospective, multicenter, single-blinded, noninferiority randomized trial across 36 centers in China. Eligible patients had myocardial ischemia and 1 or 2 de novo target lesions. Patients were randomly assigned (1:1) to IBS or CoCr-EES, with allocation masked. Optical coherence tomography (OCT) was performed in the first 25 participant pairs. Clinical follow-up was scheduled at 1, 6, and 12 months, and annually to 5 years, with angiographic and OCT follow-up at 2 years. The primary endpoint was 2-year angiographic in-segment late lumen loss (LLL). Powered secondary endpoints included target vessel quantitative flow ratio (QFR) and OCT-derived cross-sectional mean flow area. Other secondary endpoints included target lesion failure (cardiac death, target vessel myocardial infarction [MI], or ischemia-driven target vessel revascularization), the patient-oriented composite endpoint (all-cause death, MI, or any revascularization), their individual components, and device thrombosis. RESULTS: Between March 10 and December 13, 2022, 518 patients were randomized to IBS (n = 259) or CoCr-EES (n = 259). At 2 years, lesion-level in-segment LLL was 0.28 (0.52) mm with IBS and 0.23 (0.43) mm with CoCr-EES (difference: 0.08 mm; 95% CI: -0.02 to 0.18; P = 0.03). Mean QFR was 0.90 (0.13) with IBS and 0.92 (0.09) with CoCr-EES (difference: -0.02; 95% CI: -0.04 to 0; P = 0.05). Mean OCT flow area was 6.92 (3.48) mm with IBS and 6.64 (2.44) mm with CoCr-EES (difference: 0.27; 95% CI: -0.09 to 0.63; P < 0.0001). Two-year target lesion failure occurred in 7.4% of IBS patients and 5.4% of CoCr-EES patients (HR: 1.37; 95% CI: 0.69-2.73; P = 0.37). No significant between-group differences in the rates of patient-oriented composite endpoint, death, or MI were present between the 2 groups. No scaffold thromboses occurred in the IBS group, whereas 1 stent thrombosis occurred with CoCr-EES. Binary restenosis and revascularization rates were higher with IBS, however, most such events were non-ischemia-driven. CONCLUSIONS: In IRONMAN-II, the sirolimus-eluting IBS was noninferior to CoCr-EES for 2-year in-segment LLL, QFR, and OCT-derived flow area. Clinical event rates were also comparable between groups although non-ischemia-driven revascularization rates were higher after IBS. Longer-term follow-up is necessary to demonstrate whether late benefits are realized after complete IBS resorption. (A Clinical Investigation to Evaluate the Safety and Efficacy of IBS in Patients With Coronary Artery Disease; NCT05206084).
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