Hemodynamic Alteration in Aortic Valve Stenosis: CFD Insights from Leaflet-Resolved Models

Area of Science:

• Cardiovascular Physiology
• Biomedical Engineering
• Fluid Dynamics

Background:

• Aortic valve stenosis (AVS) is a common cardiovascular disease causing valve narrowing and restricted blood flow.
• Hemodynamic changes in AVS, including elevated velocities and shear stresses, are critical for disease progression but not fully understood.
• Early detection and intervention strategies require a deeper understanding of AVS-related hemodynamics.

Purpose of the Study:

• To computationally characterize aortic hemodynamics across varying degrees of AVS.
• To investigate the relationship between stenosis severity and key hemodynamic parameters.
• To provide insights into AVS-induced mechanical stresses and their potential role in endothelial dysfunction.

Main Methods:

• Utilized Computational Fluid Dynamics (CFD) with a 3D steady-state model.
• Employed idealized leaflet geometries to simulate healthy, mild, moderate, and severe stenosis.
• Evaluated parameters: velocity distribution, wall shear stress (WSS), pressure loss coefficient, and helicity.

Main Results:

• Observed a non-linear increase in jet velocity and WSS with increasing stenosis severity.
• Peak velocities ranged from 1.08 m/s (healthy) to 4.7 m/s (severe); peak WSS from 11 Pa to 122 Pa.
• Severe stenosis led to eccentric jets, increased turbulence, and expanded recirculation zones, alongside higher helicity and pressure loss.

Conclusions:

• Valve leaflet geometry significantly influences aortic blood flow dynamics.
• Stenosis severity directly correlates with altered hemodynamic forces, including elevated WSS.
• Findings offer physiologically relevant insights into AVS progression and potential mechanisms of endothelial dysfunction, aiding early detection.