Computational Analysis of Mechanical Performance for Composite Polymer Biodegradable Stents

Area of Science:

• Biomaterials Engineering
• Medical Device Design
• Computational Mechanics

Background:

• Bioresorbable stents (BRS) are advanced vascular scaffolds for minimally invasive procedures, aiming to improve upon bare-metal stents (BMS) and drug-eluting stents (DES).
• Bioprinting technology enables the creation of composite BRS by combining biodegradable polymers, potentially enhancing mechanical properties like strength and flexibility compared to single-material designs.

Purpose of the Study:

• To evaluate the mechanical performance of novel composite bioresorbable stents (BRS) fabricated from polylactic acid (PLA) and polycaprolactone (PCL).
• To investigate how different material combinations and layer arrangements influence stent behavior during crimping and expansion.

Main Methods:

• Finite element analysis (FEA) was employed to simulate stent crimping and expansion processes.
• Sixteen unique four-layer composite stent configurations using PLA and PCL were analyzed.
• Mechanical parameters including stress, strain, elastic recoil, and foreshortening were evaluated.

Main Results:

• Composite stent configurations containing at least one PLA layer exhibited similar mechanical behavior.
• Pure polycaprolactone (PCL) stents demonstrated greater elastic recoil and less foreshortening compared to PLA and composite structures.
• The volumetric ratio of PLA and PCL significantly influenced recoil and foreshortening more than the layer arrangement.

Conclusions:

• Composite BRS provide a pathway to customize mechanical characteristics for vascular scaffolds.
• These findings suggest potential for developing personalized or plaque-specific stents with tailored performance.