Arterial clamping: finite element simulation and in vivo validation

Area of Science:

• Biomedical Engineering
• Cardiovascular Surgery
• Computational Mechanics

Background:

• Cardiovascular interventions like arterial clamping cause iatrogenic tissue damage.
• Reducing intraoperative trauma is crucial for patient outcomes.
• Understanding damage mechanisms informs the design of less traumatic surgical instruments.

Purpose of the Study:

• To develop and validate a finite element model for simulating rat abdominal aorta clamping.
• To investigate the influence of residual strains, clamp geometry, and material properties on tissue stress.
• To provide insights into mechanical loading and damage mechanisms during arterial clamping.

Main Methods:

• Finite element simulation of rat abdominal aorta clamping, including material nonlinearity, large deformations, contact, and residual strains.
• Derivation of mechanical parameters from inflation experiments.
• In vivo validation using Wistar rat clamping experiments to measure clamping force.

Main Results:

• Simulations identified significant stress concentrations, particularly with corrugated clamp designs.
• Residual strains were shown to lower stress gradients through the aortic wall.
• Variations in material properties (±17%) impacted maximum and minimum principal stresses.
• Modeled clamping force closely matched experimental measurements.

Conclusions:

• Finite element modeling is essential for understanding the relationship between mechanical loading and tissue damage in cardiovascular interventions.
• The study highlights the importance of considering residual strains and clamp geometry for minimizing iatrogenic trauma.
• The validated model serves as a valuable tool for designing safer surgical instruments and optimizing clamping techniques.