Modeling the role of arterial windkessel in the enhancement and synchronization of low frequency vasomotor activity

Arterial Windkessel mechanisms and arterial pressure (AP) low frequency (LF) waves were investigated by means of simple lumped models of a compliant resistant/arterial tree and of flow regulation in peripheral vascular districts (PVDs) with three types of feedback: 1) delay, 2) Van der Pol oscillator, 3) relay; all were able to actively compensate flow changes and to simulate peripheral LF vasomotion. Each PVD connected to a Windkessel compartment displayed a reduction and a disappearance of oscillations with low compliance, when the Windkessel equivalent time constant T_eq fall below 2s. Two PVDs connected to the same Windkessel tended to phase opposition with a negative interference canceling their LF oscillations from AP, With a modest neural drive, cancellation was imperfect and AP waves appeared. Vasomotion, arterial compliances and neural triggers are all essential in forming LF AP variability.