Peak systolic or maximum intra-aneurysmal hemodynamic condition? Implications on normalized flow variables.

Area of Science:

• Biomedical Engineering
• Medical Imaging
• Computational Fluid Dynamics

Background:

• Computational Fluid Dynamics (CFD) is used to analyze intra-aneurysmal hemodynamics.
• Uncertainty in patient-specific flow data necessitates using various physiological flow conditions.
• Intra-aneurysmal hemodynamics are typically normalized due to flow condition uncertainties.

Purpose of the Study:

• To investigate temporal changes in intra-aneurysmal and arterial hemodynamics.
• To assess the impact of different physiological flow conditions on these hemodynamic parameters.

Main Methods:

• Utilized eleven image-based aneurysm models.
• Performed CFD simulations under pulsatile flow conditions.
• Calculated velocity magnitude and wall shear stress (WSS) throughout the cardiac cycle.

Main Results:

• Maximum hemodynamic conditions did not consistently occur at peak systole.
• The timing of maximum hemodynamics shifted based on aneurysm size, flow rate, vasculature, and flow stability.
• Significant differences (up to 65%) were observed between peak systolic WSS and maximum WSS.
• Velocity and WSS showed considerable variability depending on the parent artery segment, especially near peak systole.

Conclusions:

• When calculating peak intra-aneurysmal stress, using the time of maximum WSS is preferable to peak systolic WSS.
• Normalization of intra-aneurysmal hemodynamics should employ variables independent of arbitrary parent artery segments.