Flow patterns in the abdominal aorta under simulated postprandial and exercise conditions: an experimental study

Area of Science:

• Cardiovascular Science
• Biomedical Engineering
• Medical Fluid Dynamics

Background:

• Hemodynamic factors are linked to atherosclerotic plaque localization in the carotid bifurcation.
• Flow patterns in the abdominal aorta may similarly dictate plaque distribution.

Purpose of the Study:

• To characterize flow patterns in a glass model of the abdominal aorta under varying outflow conditions.
• To investigate the relationship between flow dynamics and potential sites of atherosclerotic plaque formation.

Main Methods:

• A glass model of the abdominal aorta with major branches was used.
• Outflow resistances were manipulated to simulate resting, postprandial, and exercise states.
• Flow patterns were visualized using multi-colored dye and recorded via photography and videography.

Main Results:

• Flow separation and stagnation were observed at the posterior wall opposite mesenteric artery origins under resting and postprandial conditions.
• Secondary flow patterns with counterrotating vortices were present in the infrarenal aorta during rest and postprandial states, but absent during exercise.
• These flow alterations disappeared with increased flow velocity during exercise.

Conclusions:

• Flow separation and secondary flow patterns in the abdominal aorta may predispose to atherosclerotic plaque formation.
• Increased flow velocity during exercise may have a protective effect by reducing these adverse hemodynamic conditions.
• Physical fitness may offer cardiovascular benefits partly through these hemodynamic modifications.