This study aimed to investigate the long-term biocompatibility, safety, and degradation of the ultrathin nitrided iron bioresorbable scaffold (BRS) in vivo, encompassing the whole process of bioresorption in porcine coronary arteries. Fifty-two nitrided iron scaffolds (strut thickness of 70 μm) and 28 Vision Co-Cr stents were randomly implanted into coronary arteries of healthy mini-swine. The efficacy and safety of the nitrided iron scaffold were comparable with those of the Vision stentwithin 52 weeks after implantation. In addition, the long-term biocompatibility, safety, and bioresorption of the nitrided iron scaffold were evaluated by coronary angiography, optical coherence tomography, micro-computed tomography, scanning electron microscopy, energy dispersive spectrometry and histopathological evaluations at 4, 12, 26, 52 weeks and even at 7 years after implantation. In particular, a large number of struts were almost completely absorbed in situ at 7 years follow-up, which were first illustrated in this study. The lymphatic drainage pathway might serve as the potential clearance way of iron and its corrosion products.
Keywords: BRS, bioresorbable scaffold; Bioresorbable scaffold; Completely bioresorbable; DES, drug-eluting stent; ECs, endothelial cells; EDS, energy dispersive spectrometry; IVUS, intravenous ultrasound; Micro-CT, micro-computed tomography; Nitrided iron bioresorbable coronary scaffold; OCT, optical coherence tomography; PCI, percutaneous coronary intervention; Preclinical study; QCA, quantitative coronary angiography; SEM, scanning electron microscope.
© 2022 The Authors.