A multi-dimensional non-uniform corrosion model for bioabsorbable metallic vascular stents

Area of Science:

• Biomaterials Engineering
• Medical Device Design
• Corrosion Science

Background:

• Bioabsorbable metallic vascular stents (BMVSs) offer revolutionary potential in vascular interventions.
• Understanding in vivo corrosion of BMVS materials is crucial for clinical application.
• Current models lack the detail to capture complex degradation mechanisms.

Purpose of the Study:

• To develop a multi-dimensional, non-uniform corrosion model for in vivo implants.
• To simulate the corrosion rate and mechanical integrity of magnesium (Mg) alloy AZ31 BMVSs.
• To provide insights for optimizing BMVS product development.

Main Methods:

• Developed a corrosion model based on continuum damage mechanics for Mg alloy AZ31.
• Calibrated the model using three degradation experiments measuring multi-dimensional corrosion, mass loss, and mechanical integrity.
• Implemented the model into a finite element framework for in vivo degradation simulation.

Main Results:

• Established a proportional relationship between BMVS corrosion and exposed surface area.
• Observed a non-linear decline in mechanical integrity with increasing mass loss.
• The model and simulation accurately captured morphological and mechanical changes during corrosion.

Conclusions:

• The proposed model accurately simulates in vivo degradation of bioabsorbable metallic implants.
• This work offers a technical solution to enhance BMVS degradation modeling accuracy.
• Findings can optimize the future design and development of BMVSs.