A biodegradable polymer stent with high radial performance: Potential for treatment of portal vein stenosis

Abstract

Biodegradable polymer stents have a wide application prospect in the treatment of vascular stenosis diseases. However, weak radial performance of polymer stents hinders the treatment of the diseases with high demand for radial supporting, such as portal vein stenosis. According to previous research, the constraint mode between monofilaments is a key factor that affects the radial performance of polymer braided stent. In this work, a series of Poly(l‐lactic acid) (PLLA) stents with the elastomer coating were prepared by ultrasonic spraying process to realize the constraints of monofilament cross points. The results are showed that the radial stiffness and peak force of the coated stent are significantly increased, up to 28 and 35 times higher than that of the bare stent. It is found that the cross points are constrained by the coating, which improves the constraining force between the monofilaments resulting in the increase of the radial force during the deformation process. More importantly, the mechanism of action between the radial force of the coated stent and the mechanical performance of elastic coating has been proposed, revealing a significant positive correlation between them. The radial force of the coated stent could be quantitatively regulated by the six‐arm poly(l‐lactide‐co‐ε‐caprolactone) (6SPLCL) coating cross‐linked by Hexamethylene diisocyanate (HDI) in different proportions. Finally, we build a mechanical model of stents and find that there is a consistency between the theoretical curve and the actual curve trend. This provides further research and expands the application scope for improving the radial supporting performance of the biodegradable polymer stent.