Numerical simulation of the blood flow through the coronary artery stenosis: Effects of varying eccentricity

Area of Science:

• Cardiovascular Science
• Biomedical Engineering
• Fluid Dynamics

Background:

• Coronary artery disease (CAD) is often caused by arterial stenoses (blockages).
• Previous models assumed axisymmetric stenosis, but real-world coronary artery stenoses are frequently asymmetric.
• Asymmetric stenosis significantly impacts blood flow dynamics and cardiovascular health.

Purpose of the Study:

• To investigate the hemodynamic effects of asymmetric stenosis in the left anterior descending artery (LAD).
• To analyze how varying degrees of eccentricity (DoE) and stenosis (DoS) influence blood flow parameters.
• To evaluate the clinical relevance of asymmetric stenosis for patient stratification.

Main Methods:

• Developed a computational model of an asymmetric stenosis in the LAD.
• Solved incompressible Navier-Stokes equations for resting and hyperemic flow rates.
• Calculated key hemodynamic parameters: wall shear stress (WSS), oscillatory shear index (OSI), and fractional flow reserve (FFR).

Main Results:

• Eccentricity deflects blood flow, altering downstream behavior and increasing recirculation zone dimensions.
• Increased DoE expands the transverse recirculation zone; increased DoS primarily affects its longitudinal dimension.
• Asymmetric stenosis leads to significant pressure loss (FFR < 0.8) and promotes secondary flow development.

Conclusions:

• Asymmetric stenosis significantly alters hemodynamics, impacting FFR and potentially leading to adverse arterial remodeling.
• Incorporating the degree of eccentricity (DoE) alongside the degree of stenosis (DoS) is crucial for accurate CAD assessment.
• Considering stenosis asymmetry can enhance patient stratification and guide clinical decision-making for CAD patients.