Contrastive analysis of degradation behavior for WE43 magnesium alloy stents in cerebrovascular versus coronary hemodynamic environments

• Cerebral arteries exhibit higher blood-flow velocities and shear stresses than coronary vessels. • WE43 stents corroded fastest in the internal carotid artery, forming deep pits within 24 h. • Corrosion products were mainly Mg₃(PO₄)₂ and Mg(OH)₂; phosphorus enrichment positively correlated with degradation rate. • High shear mechanically disrupted Mg(OH)₂ passivation, accelerating exposure and shifting corrosion from uniform to localized pitting. • FSI simulations plus biomimetic pulsatile-flow corrosion tests revealed site-specific mechanics–corrosion coupling. Cerebrovascular disease is the leading cause of death in China, and the long-term presence of non-degradable metal stents in neurointerventional therapy poses significant challenges. Biodegradable stents offer a promising solution, with magnesium (Mg) alloys emerging as a focal research area due to their favorable biocompatibility. However, most degradable Mg alloy stents are developed for cardiovascular applications, and their degradation behavior within the cerebral hemodynamic environment remains unclear. This study comparatively investigated the corrosion degradation of WE43 Mg alloy stents in the internal carotid artery (ICA), middle cerebral artery (MCA), and left anterior descending coronary artery (LAD), focusing on key hemodynamic characteristics distinguishing cerebral from coronary blood flow. Results demonstrated significantly higher blood flow velocities and consequently greater shear stresses acting on stents in cerebral arteries compared to coronary arteries. After 24 h, the remaining volume of the stent at the LAD site was 95.78%, at the MCA site it was 89.55%, and at the ICA site it was only 84.67%. The ICA location exhibited the fastest stent corrosion rate, developing deep pit-shaped defects on stent surfaces after 24 h. Corrosion products consisted predominantly of Mg₃(PO₄)₂ and Mg(OH)₂, with the degree of phosphorus (P) enrichment positively correlating with the corrosion rate. High shear stress compromised the integrity of the protective surface Mg(OH)₂ layer, thus accelerating substrate exposure to corrosive media and shifting corrosion behavior from uniform to localized. This research provides experimental insights into the in-service degradation of biodegradable Mg alloys under complex hemodynamic conditions and offers theoretical support for designing next-generation intracranial stents with controlled degradation profiles.