3D printed polymeric stent design: Mechanical testing and computational modeling
Francesc Canalejo-Codina, Mariola Cano-Morenilla, Jordi Martorell, Mercedes Balcells, Marta Pegueroles, Andrés‐Amador García‐Granada
Abstract
• Bioresorbable stents were manufactured and subjected to parallel and radial crush resistance testing. • Stents exhibited a parallel crush resistance of 0.11 N/mm and much higher radial forces reaching up to 1.80 N/mm. • Parallelly compressed stents showed stress over 50 MPa, while radial compression caused localized plastic strain up to 30 %. • Yield strain of 5% proved to be the most accurate value for matching computational and experimental results for PLCL stents. Polymer-based bioresorbable scaffolds (BRS) aim to reduce the long-term issues associated with metal stents. Yet, first-generation BRS designs experienced a significantly higher rate of clinical failures compared to permanent implants. This prompted the development of alternative scaffolds, such as the poly(L-lactide-co-ε-caprolactone) (PLCL) solvent-casted stent, whose mechanical performance has yet to be addressed. This study examines the mechanical behavior of this novel scaffold across a wide range of parallel and radial compression diameters. The analysis highlights the scaffold’s varying responses under different loading conditions and provides insights into interpreting simulation model parameters to accurately reflect experimental results. Stents demonstrated a parallel crush resistance of 0.11 N/mm at maximum compression, whereas the radial forces were significantly higher, reaching up to 1.80 N/mm. Additionally, the parallel test keeps the stent in the elastic regime, with almost no regions exceeding 50 MPa of stress, while the radial test causes significant structural deformation, with localized plastic strain reaching up to 30 %. Results showed that underestimating yield strain in computational models leads to discrepancies with experimental results, being 5 % the most accurate value for matching computational and experimental results for PLCL solvent-casted stents. This comprehensive approach is vital for optimizing BRS design and predicting clinical performance.