Balancing the biodegradability and mechanical integrity of a bioresorbable scaffold (BRS) with time after implantation to match the remodeling of the scaffolded blood vessel is important, but a key challenge in doing so remains. This study presents a novel intercalated structure of a metallic BRS by introducing a nanoscale Zn sacrificial layer between the nitrided Fe platform and the sirolimus-carrying poly(d,l-lactide) drug coating. The PDLLA-Zn-FeN BRS shows a multistage biodegradation behavior, maintaining mechanical integrity at the initial stage and exhibiting accelerated biodegradation at the subsequent stage in both rabbit abdominal aortas and human coronary arteries, where complete biodegradation was observed about 2 years after implantation. The presence of the nanoscale Zn sacrificial layer with an adjustable thickness also contributes to the tunable biodegradation of BRS and allows the reduction of the metallic strut thickness to 53 μm, with radial strength as strong as that of the current permanent drug-eluting stents.
Coronary calcified nodules are an uncommon but important substrate for acute coronary syndromes, stent underexpansion, and recurrent target lesion revascularization. This consensus integrates pathologic, imaging, prognostic, and interventional evidence to guide practical decision-making. Intravascular imaging is essential for diagnosis, mechanism definition, and procedural optimization. Optical coherence tomography provides superior assessment of cap disruption and thrombus, whereas intravascular ultrasound remains valuable when contrast exposure or lesion crossing limits optical coherence tomography. Treatment should be tailored to lesion crossability, calcium distribution, and the need for mechanical scaffolding. No calcium-modification device or drug-eluting stent vs drug-coated balloon strategy has demonstrated consistent superiority. The proposed type IIa/IIb framework is hypothesis-generating and requires prospective validation. Calcified nodule-related target lesion failure should be managed by correcting the dominant mechanical mechanism before antiproliferative therapy. These recommendations emphasize individualized, imaging-guided percutaneous coronary intervention and identify priorities for prospective comparative research.