Integrating stent design and microstructural characterization to improve clinical outcomes of bioresorbable stents

Abstract

Bioresorbable stents were conceived to revolutionize the treatment of cardiovascular diseases. However, their significant benefits were overshadowed by a higher clotting rate compared to permanent implants. This clinical failure is linked to strain-induced microstructural disruptions during fabrication and implantation, resulting in heterogeneous loss of structural integrity. The non-gradual loss of support, combined with faster, localized polymer deterioration, directly contributes to the clinical failure observed in bioresorbable stents. Leveraging this understanding marks a significant advancement toward their safe reintroduction. However, the extent to which a stent’s stress distribution interacts with the polymer’s microstructure remains understudied. This study advances the existing knowledge on bioresorbable stents by establishing a framework for comprehending the microstructural properties that emerge from stent fabrication and implantation, ultimately aiming to improve clinical outcomes. The analysis addresses structural degradation and thrombogenicity of the devices, linking these aspects to the microstructural characteristics of various poly(L-lactide-co-ε-caprolactone) stent configurations. The configuration with the polymer microstructure tailored to the stress profile of the stent design presented the best performance. These findings emphasize the critical need to align the as-manufactured material properties with the stress distribution during implantation and provide powerful tools and strategies to cast bioresorbable stents that outperform current cardiovascular stents.