Simulating re-reflections of arterial pressure waves at the aortic valve using difference equations

Area of Science:

• Cardiovascular Physiology
• Biomedical Engineering
• Mathematical Modeling

Background:

• The influence of arterial pressure wave re-reflections at the aortic valve on aortic wave shape is not well understood.
• Accurate modeling of arterial hemodynamics requires understanding wave reflections.

Purpose of the Study:

• To develop and test a model for simulating arterial pressure wave re-reflections at the aortic valve.
• To investigate the impact of aortic valve re-reflections on aortic pressure wave characteristics.

Main Methods:

• Utilized a mathematical difference equation model to simulate aortic blood pressure.
• Separated aortic blood pressure into forward and backward components.
• Incorporated reflection percentages and a reflection coefficient at the aortic valve, simulating various scenarios.

Main Results:

• Physiological pressure curves were achieved only when re-reflections were assumed throughout the cardiac cycle.
• Higher reflection coefficients at the aortic valve increased systolic and diastolic pressure.
• The augmentation index was significantly influenced by the systolic reflection coefficient.

Conclusions:

• The developed model adequately simulates aortic pressure, including re-reflections at the aortic valve.
• Arterial pressure wave transmission models should incorporate re-reflections due to their strong dependence on the reflection coefficient.
• Re-reflections warrant consideration in arterial pulse wave analysis methods.