Steady flow development past valve prostheses in a model human aorta. I. Centrally occluding valves

Area of Science:

• Biomedical Engineering
• Fluid Dynamics
• Cardiovascular Research

Background:

• Understanding blood flow dynamics in the aorta is crucial for diagnosing and treating cardiovascular diseases.
• Previous studies have explored flow patterns in healthy aortas, but the impact of prosthetic devices requires further investigation.

Purpose of the Study:

• To investigate the effects of centrally occluding caged ball valves on steady flow development in a model human aorta.
• To analyze changes in velocity profiles and vortex formation in the ascending aorta and aortic arch.

Main Methods:

• Utilized laser-Doppler anemometry (LDA) for precise, non-invasive velocity measurements.
• Employed a steady flow model simulating human aortic conditions.
• Investigated flow development with and without centrally occluding caged ball valves.

Main Results:

• In the absence of valves, Dean vortices were observed in the mid-arch region.
• Centrally occluding valves induced asymmetric velocity profiles in the ascending aorta, with increased gradients towards the inner wall.
• These valves inhibited the development of Dean vortices in the aortic arch.
• No significant effect of the valves was observed on velocity profiles in the brachio-cephalic artery.

Conclusions:

• Centrally occluding caged ball valves significantly alter hemodynamics in the ascending aorta.
• The presence of these valves disrupts normal flow patterns, preventing physiological vortex formation in the aortic arch.
• These hemodynamic changes may have implications for the long-term performance and biocompatibility of such prosthetic devices.