Theoretical model for assessing haemodynamics in arterial networks which include bypass grafts.

The paper presents a theoretical model which can be used to simulate a vascular network which includes loops and bypass grafts, a feature not possible with previous models. Using the linearised Navier-Stokes equations, the linearised equation of a uniform thick-walled viscoelastic tube, and the equation of continuity, the model is applied to a vascular network which includes a bypass graft. This method represents each segment of an artery or graft by a four-terminal-network whose A, B, C, D parameters are functions of the frequency and physical characteristics of the segment. The model predicts the flow and pressure waveforms at any point in the human arterial network very accurately when compared with data obtained from normal patients, patients with arterial stenoses and for hypertensive patients. The model also gives results which are in close agreement with hydraulic experimental data for the input impedance of systems with bypass loops.