Arterial wave dynamics preservation upon orthostatic stress: a modelling perspective

Area of Science:

• Cardiovascular Physiology
• Biomedical Engineering
• Hemodynamics

Background:

• Pressure-flow wave dynamics are crucial for arterial hemodynamics.
• Postural changes' effects on wave transmission and reflection are not fully understood.
• Existing research shows reduced central wave reflection upon upright tilting, despite cardiovascular stiffening.

Purpose of the Study:

• To investigate posture-induced arterial wave dynamics using a multi-scale modeling approach.
• To analyze changes in wave transmission, reflection, and trapping during simulated head-up tilting.
• To determine if the arterial system's optimization for wave trapping is maintained with postural changes.

Main Methods:

• Multi-scale modeling approach.
• Simulation of head-up tilting from a supine position.
• Analysis of arterial wave dynamics, including transmission, reflection, and trapping.

Main Results:

• Vessel lumens at arterial bifurcations remain well-matched for forward wave propagation.
• Central wave reflection is reduced due to weakened pressure waves from cerebral autoregulation.
• Backward wave trapping, a heart-protective mechanism, is preserved during upright tilting.

Conclusions:

• The human arterial system adapts remarkably to postural changes.
• Reduced central wave reflection and preserved wave trapping indicate maintained cardiovascular protection during upright posture.
• Multi-scale modeling provides insights into complex hemodynamic responses to posture changes.