A Patient-Specific Mesoscopic Fluid-Structure Interaction Model of the Coronary Artery

Area of Science:

• Biomedical Engineering
• Computational Fluid Dynamics
• Cardiovascular Research

Background:

• Patient-specific coronary artery fluid-structure interaction (FSI) models are crucial for understanding cardiovascular disease.
• Previous macroscopic FSI models provided valuable insights but lacked cellular-level resolution.

Purpose of the Study:

• To develop and validate a high-resolution mesoscopic FSI model of the coronary artery region of interest (ROI).
• To compare biomechanical parameters derived from mesoscopic and macroscopic FSI models.
• To investigate the impact of mesoscopic FSI model-derived conditions on endothelial cell behavior.

Main Methods:

• Developed a mesoscopic FSI model in COMSOL Multiphysics with element size near endothelial cell dimensions.
• Calculated blood flow-induced shear stress, vascular wall stress, and tensile strain in normal and stenosed coronary artery ROIs.
• Applied calculated shear stress and tensile strain to human coronary artery endothelial cells using a shearing-stretching device.
• Measured endothelial cell morphology and ICAM-1 expression as response indicators.

Main Results:

• The mesoscopic FSI model achieved significantly improved spatial resolution.
• Observed significant differences in shear stress and circumferential strain between mesoscopic and macroscopic models, particularly in 50% stenosis.
• Endothelial cell responses (morphology, ICAM-1 expression) were significantly affected by biomechanical conditions derived from the mesoscopic model.

Conclusions:

• Mesoscopic FSI models offer superior local biomechanical characterization compared to macroscopic models.
• Differences in shear stress and strain from mesoscopic models significantly influence endothelial cell responses.
• Large-scale FSI models may be insufficient for accurately assessing cellular-level biomechanical conditions in coronary arteries.