Pressure-flow travelling waves are a key topic for understanding arterial haemodynamics. However, wave trasmission 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 the central level (ascending aorta, aortic arch) decreases during tilting to the upright position, despite the widely-proved stiffening of the cardiovascular system (CVS). Moreover, it is not known whether the optimized configuration of the arterial system typical of the supine condition - i.e., enabled propagation of direct waves vs. trapping of reflected waves, protecting the heart - is preserved or not after posture 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 remodelling of the human vasculature following posture changes, our analysis shows that: (i) vessels lumens at arterial bifurcations remain well matched in the forward direction; (ii) the reduced wave reflection observed at the central level seems to be caused by backward propagation of weakened pressure waves produced by cerebral autoregulation; and (iii) backward wave trapping is preserved upon orthostatic stress.

Reported data are steady-state supine and upright standing (i.e. 90° head-up posture) time series of primary investigated hemodynamic variables over a single heartbeat. These have been obtained via the mathematical model described in the main manuscript. The MatLab files enclosed in this repository reports the model's routine of computation and function calls performed at each time step.

MatLab