Multi-objective optimisation of material properties and strut geometry for poly(L-lactic acid) coronary stents using response surface methodology

PLoS One. 2019 Aug 26;14(8):e0218768. doi: 10.1371/journal.pone.0218768. eCollection 2019.

Abstract

Coronary stents for treating atherosclerosis are traditionally manufactured from metallic alloys. However, metal stents permanently reside in the body and may trigger undesirable immunological responses. Bioresorbable polymer stents can provide a temporary scaffold that resorbs once the artery heals but are mechanically inferior, requiring thicker struts for equivalent radial support, which may increase thrombosis risk. This study addresses the challenge of designing mechanically effective but sufficiently thin poly(L-lactic acid) stents through a computational approach that optimises material properties and stent geometry. Forty parametric stent designs were generated: cross-sectional area (post-dilation), foreshortening, stent-to-artery ratio and radial collapse pressure were evaluated computationally using finite element analysis. Response surface methodology was used to identify performance trade-offs by formulating relationships between design parameters and response variables. Multi-objective optimisation was used to identify suitable stent designs from approximated Pareto fronts and an optimal design is proposed that offers comparable performance to designs in clinical practice. In summary, a computational framework has been developed that has potential application in the design of high stiffness, thin strut polymeric stents.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Blood Vessel Prosthesis*
  • Coronary Vessels*
  • Materials Testing*
  • Mechanical Phenomena*
  • Polyesters*
  • Prosthesis Design / methods*
  • Stress, Mechanical

Substances

  • Polyesters
  • poly(lactide)

Grants and funding

The authors wish to acknowledge funding from the Engineering and Physical Sciences Research Council (EPSRC) (S3804ASA) and the Marie Skłodowska-Curie Research and Innovation Staff Exchange (RISE), grant agreement 691238. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.