Experimental Tests, FEM Constitutive Modeling and Validation of PLGA Bioresorbable Polymer for Stent Applications.

Jakub Bukala,Jerzy Małachowski,Lukasz Mazurkiewicz,Kamil Sybilski,Piotr P Buszman

doi:10.3390/ma13082003

Abstract

The use of bioresorbable polymers such as poly(lactic-co-glycolic acid) (PLGA) in coronary stents can hypothetically reduce the risk of complications (e.g., restenosis, thrombosis) after percutaneous coronary intervention. However, there is a need for a constitutive modeling strategy that combines the simplicity of implementation with strain rate dependency. Here, a constitutive modeling methodology for PLGA comprising numerical simulation using a finite element method is presented. First, the methodology and results of PLGA experimental tests are presented, with a focus on tension tests of tubular-type specimens with different strain rates. Subsequently, the constitutive modeling methodology is proposed and described. Material model constants are determined based on the results of the experimental tests. Finally, the developed methodology is validated by experimental and numerical comparisons of stent free compression tests with various compression speeds. The validation results show acceptable correlation in terms of both quality and quantity. The proposed and validated constitutive modeling approach for the bioresorbable polymer provides a useful tool for the design and evaluation of bioresorbable stents.

Highlights

Heart disease is a leading cause of hospitalization and death worldwide (33% of all deaths) [1].The dissemination of percutaneous coronary intervention (PCI) as the preferred method for revascularization has revolutionized the treatment of ischemic heart disease (IHD) over the past 20 years [1]
Its main disadvantage is the implementation of a permanent metal prosthesis in the vessel wall, which can lead to potential inflammation, late-stent thrombosis, neoatherosclerosis, and restenosis [5,6]
The bioresorbable poly(lactic-co-glycolic acid) (PLGA) polymer material considered here is characterized by relatively low stiffness, strain rate sensitivity, a significant decrease in observed strength after yield, and plastic behavior with limited hardening

Summary

Introduction

Heart disease is a leading cause of hospitalization and death worldwide (33% of all deaths) [1]. The dissemination of percutaneous coronary intervention (PCI) as the preferred method for revascularization (which relieves narrowing) has revolutionized the treatment of ischemic heart disease (IHD) over the past 20 years [1]. PCI is an effective and less aggravating alternative to coronary artery bypass grafting (CABG). Metallic stents are accepted as the standard in interventional cardiology [4]. Despite high effectiveness and a relatively low complication risk, PCI is still not an ideal technique. Its main disadvantage is the implementation of a permanent metal prosthesis in the vessel wall, which can lead to potential inflammation, late-stent thrombosis, neoatherosclerosis, and restenosis [5,6]

Methods

Discussion

Conclusion