Valvular and systemic arterial hemodynamics in aortic valve stenosis. A model-based approach

Area of Science:

• Cardiovascular Physiology
• Biomedical Engineering
• Clinical Diagnostics

Background:

• Assessing aortic valve stenosis severity is complicated by flow-dependent measurements.
• The pressure gradient across a stenotic aortic valve may vary with arterial system characteristics.

Purpose of the Study:

• To investigate the dependence of aortic valve stenosis severity on arterial circulation properties.
• To develop a model predicting transvalvular pressure gradients based on arterial hemodynamics.

Main Methods:

• An analog model of the systemic arterial circulation with a stenotic aortic valve was developed.
• High-fidelity pressure recordings from cardiac catheterizations were analyzed.
• Model predictions were compared to measured transvalvular gradients at rest and during exercise.

Main Results:

• The model demonstrated stenosis severity dependence on arterial resistive and capacitive properties.
• A strong correlation was found between measured and predicted mean transvalvular gradients (r2 = .90 at rest, r2 = .80 with exercise).
• Stenosis coefficients A and B remained relatively constant, validating the model's parameters.

Conclusions:

• Transvalvular hemodynamics in aortic valve stenosis are significantly influenced by arterial system properties.
• The developed model accurately predicts transvalvular gradients.
• This model may improve the clinical assessment of aortic valve stenosis severity under diverse conditions.