Effects of stress on degradation of biodegradable metal for vascular stent application: A review

BACKGROUND: The combined action of physiological stress and corrosion may cause stress-assisted corrosion and cracking of biodegradable vascular stents, and even lead to early failure of the stents. OBJECTIVE: To review the degradation of biodegradable metal stents under physiological stress environment and the relevant mechanisms. METHODS: PubMed and CNKI databases were searched for relevant articles published from 2000 to 2018, using the keywords of “biodegradable, degradation, stress” in English and Chinese, respectively. RESULTS AND CONCLUSION: Magnesium, iron and zinc are the representatives of biodegradable metal materials, which have shown good application prospects in the field of vascular stents. Biodegradable stents work via balloon dilatation, and then support vessels until the complete revascularization under complex stresses, including tensile stress, compressive stress, shear stress and cyclic loading. We cannot ignore the effects of stress on the degradation of biodegradable metals; otherwise, the implantation of biodegradable metal stents may fail due to fastened attenuation of mechanical performance or stent fracture. To explore the effect of stress on biodegradable metal stent degradation and its relevant mechanism is crucial to the modification, configuration design and optimization of vascular stent materials.