The arterial system characterised in the time domain

Area of Science:

• Cardiovascular physiology
• Biomedical engineering
• Hemodynamics

Background:

• The arterial tree's characteristics can be understood through its impulse response.
• Reflections within the arterial system significantly impact pressure wave propagation.

Purpose of the Study:

• To characterize the arterial tree using its impulse response to flow.
• To identify and locate distinct reflection sites within the arterial system.

Main Methods:

• An impulse of flow was applied to the arterial system using an occluder around the ascending aorta.
• The resulting pressure (impulse response) was analyzed to identify peaks and decay patterns.
• Pulse wave velocity was used to calculate the location of reflection sites.

Main Results:

• The impulse response exhibited an initial peak, exponential decay (diffuse reflections), and two superimposed peaks (distinct reflections).
• Distinct reflection sites were located distally to the brachiocephalic/subclavian arteries and the descending aorta.
• Vasodilation/vasoconstriction affected diffuse reflections but not the location of distinct reflection sites.

Conclusions:

• The impulse response provides a detailed characterization of the arterial tree, including windkessel properties and reflection sites.
• Distinct arterial reflections are linked to specific anatomical locations and can be identified using pulse wave velocity.
• Pharmacological interventions primarily influence diffuse reflections, highlighting the stability of major reflection sites.