Biodegradable Stents: Biomechanical Modeling Challenges and Opportunities

Abstract

Biodegradable implants show great potential in many areas of medicine, and have already demonstrated success in simple applications such as sutures. For more complex devices, such as vascular stents, there are considerable challenges associated with the use of biodegradable materials. These materials typically are weaker than the metals currently used to construct stents, so it is difficult to ensure sufficient strength to prop open the artery and alleviate symptoms acutely. It is even more challenging to design a stent that provides structural support for a predictable, appropriate time to facilitate artery healing. These challenges are evident when one considers that there are no biodegradable stents on the US market despite more than 20 years of development efforts. This review summarizes previous efforts at implementing biodegradable stents, discusses the specific challenges involved, and presents a recently developed biodegradable material modeling framework that can benefit this exciting field.

Research into biodegradable polymeric stents: a review of experimental and modelling work

“…There is not a model available yet to model the degradation process as well as property changes, especially to predict both biodegradable implant mechanics and its interaction with blood vessel. For instance, finite-element models were used to predict the recoil and collapse behaviour of polymer stent design by considering the elastic and/or inelastic behaviour of the polymer [46,47] , but neglecting any changes of material properties that occur [41] with degradation [48] . At human-body temperature, the biodegradation process is a combined effect of time and local deformation.…”

“…The worldwide coronary stent market is worth over $7 billion and forecasted to grow by more than 5% annually [1] . Over the past three decades, there have been significant improvements made in stent materials and designs, especially for the drug-eluting stents (DESs) which were firstly approved by Food and Drug Administration (FDA) of USA in 2002.…”

A Novel Approach to Design Lesion-Specific Stents for Minimum Recoil

“…Recent studies [22,23] have suggested bioresorbable stents, commonly referred to as scaffolds, as a possible future option for coronary intervention. As a consequence, polylactic acid (PLA) was chosen as the material during the design process.…”

Modeling and simulation of material degradation in biodegradable wound closure devices

“…41 We assume d 5 0 for a virgin material while d 5 1 for a completely degraded material. These reaction equations would take place along the degradation and updated in the energy minimization procedure.…”