February 2023

The paper Arterial wave dynamics preservation upon orthostatic stress: a modelling perspective, by M. Fois, L. Ridolfi, S. Scarsoglio and has been accepted for publication in Royal Society Open Science, doi: 10.1098/rsos.221257 (2023).

Abstract

Pressure-flow travelling waves are a key-topic for understanding arterial haemodynamics. However, wave transmission and reflection processes induced by body posture changes have not been thoroughly explored yet. Current in-vivo research has shown that the amount of wave reflection detected at a central level (ascending aorta, aortic arch) decreases during tilting to the upright position, despite the widely proved stiffening of the cardiovascular system (CVS). It is known that the arterial system is optimised when in the supine position, i.e. propagation of direct waves is enabled and reflected waves are trapped, protecting the heart; however, it is not known whether this is preserved with postural changes. To shed light on these aspects, we propose a multiscale modelling approach to inquire into posture-induced arterial wave dynamics elicited by simulated head-up tilting. In spite of remarkable adaptation of the human vasculature following posture changes, our analysis shows that, upon tilting from supine to upright: (i) vessel lumens at arterial bifurcations remain well matched in the forward direction; (ii) wave reflection at central level is reduced due to the backward propagation of weakened pressure waves produced by cerebral autoregulation; and (iii) backward wave trapping is preserved.

Full text is available here.