A model for passive elastic properties of rat vena cava

Area of Science:

• Biomechanics
• Biomedical Engineering
• Cardiovascular Research

Background:

• The abdominal vena cava (AVC) is crucial for venous return.
• Understanding its elastic properties under deformation is vital for cardiovascular research.
• Existing models may not fully capture the orthotropic behavior of the AVC.

Purpose of the Study:

• To introduce and validate a two-dimensional model for the elastic properties of the abdominal vena cava (AVC).
• To analyze the orthotropic deformation of the AVC using experimental data.
• To provide a phenomenological model for predicting AVC mechanical behavior.

Main Methods:

• Development of a two-dimensional membrane model based on orthotropic deformation principles.
• Experimental data acquisition from six rat vena cavae specimens using pressurization experiments.
• Phenomenological modeling of the mechanical system, decomposed into kinematic and hyperelastic components.

Main Results:

• The model reasonably reproduces experimental data from rat AVC specimens.
• Axial and circumferential stress ratios were found to depend primarily on the circumferential extension ratio.
• A correction parameter improved data reproduction but reduced physical rigor and hyperelasticity assumptions.

Conclusions:

• The proposed 2D model offers a viable approach for understanding AVC elastic properties.
• The decomposition into kinematic and hyperelastic systems provides a useful framework for analysis.
• Further refinement may be needed to balance model accuracy with physical assumptions for clinical applications.