Numerical analysis of blood flow through a stenosed artery using a coupled, multiscale simulation method.

Area of Science:

• Cardiovascular Physiology
• Computational Fluid Dynamics
• Biomedical Engineering

Background:

• Stenosed coronary arteries significantly impact blood flow and cardiac function.
• Accurate simulation of local hemodynamics within stenoses is crucial for understanding cardiovascular disease.
• Integrating global cardiovascular system models with local flow dynamics presents a computational challenge.

Purpose of the Study:

• To develop and validate a coupled computational model for simulating blood flow in stenosed coronary arteries.
• To investigate the fluid dynamics and systemic responses to coronary artery stenosis.
• To analyze the interplay between local stenosis characteristics and global cardiovascular parameters.

Main Methods:

• A hybrid approach combining a global lumped parameter model of the cardiovascular system with a local finite element method (FEM) solution.
• Utilizing the Pressure Implicit with Splitting of Operators (PISO) algorithm for the FEM solution of Navier-Stokes equations for viscous, incompressible flow.
• Coupling the models by using lumped parameter calculations for time-dependent boundary conditions and incorporating FEM-derived pressure drops to refine the lumped parameter model.

Main Results:

• The coupled simulation accurately captures local flow patterns and pressure drops in a 90% area reduction coronary artery stenosis model.
• A strong coupling between blood flow rate and stenosis resistance was observed over a cardiac cycle.
• The coupled model showed that high diastolic flow rates increase stenosis pressure drop and resistance, slightly reducing overall flow rate compared to constant resistance models.

Conclusions:

• The developed coupled modeling approach provides a robust tool for analyzing blood flow in stenosed coronary arteries.
• The study highlights the dynamic interplay between local stenosis severity and global cardiovascular regulation.
• Accurate hemodynamic assessment of stenoses requires models that account for the time-varying nature of flow and resistance.