Detailed visualization of pulsatile flow fields produced by modelled arterial stenoses

Area of Science:

• Biomedical Engineering
• Fluid Dynamics
• Cardiovascular Research

Background:

• Arterial stenosis, a narrowing of arteries, is a significant risk factor for cardiovascular diseases.
• Understanding blood flow dynamics and associated wall shear stress (WSS) is crucial for predicting stenosis severity and patient outcomes.
• Pulsatile flow in stenotic arteries creates complex flow patterns that require advanced visualization techniques.

Purpose of the Study:

• To visualize and quantify the pulsatile flow field in modelled arterial stenoses with 38% and 65% area reductions.
• To investigate the fluctuations in wall shear stress (WSS) at various locations relative to the stenosis.
• To compare the flow dynamics and WSS profiles between mild (38%) and severe (65%) arterial narrowing.

Main Methods:

• Employed a multiple trace photochromic method for flow visualization.
• Simulated pulsatile flow conditions mimicking those in a medium-sized human artery.
• Photographed flow patterns at seven axial locations simultaneously throughout the cardiac cycle.

Main Results:

• The 65% stenosis exhibited highly fluctuating WSS near the reattachment point during the turbulent phase.
• Instantaneous shear stresses in severe stenosis were at least eight times higher than upstream measurements.
• The 38% stenosis demonstrated significantly lower wall shear stress values compared to the severe stenosis.

Conclusions:

• Severe arterial stenosis (65% area reduction) induces substantial and dynamic fluctuations in wall shear stress.
• These elevated and fluctuating shear stresses in severe stenosis may pose a risk for arterial damage and complications.
• Mild stenosis (38% area reduction) results in considerably lower and less variable wall shear stress.