T-Y tube model of human ascending aortic input impedance

Abstract

This paper proposed a T-Y tube model to simulate the input impedance of arterial system. It improves and extends the asymmetric T-tube model which was first proposed by O' Rourke[1] and developed later by Liu et al.[2]. Based on the asymmetric T-tube model, a T-Y tube model was proposed by adding branching tubes which represent the iliac arteries. All the tubes are considered to be uniform, viscoelastic, longitudinally tethered cylindrical tubes. The upper tube terminates with a windkessel model, while the terminal arterioles of the lower tube are expressed as a resistance. After proper evaluation of the parameters, the impedance of the arterial system is calculated under normal physiological and hypertensive condition. The model can predict impedance in good agreement with the experimentally obtained data no matter in normal physiological condition or in pathological condition. In comparison with the asymmetric T-tube model, T-Y tube model is closer to anatomy structure of the human arterial system and at the same time much simpler than the extremely complex multiple-branching tube model. Therefore it will be a valuable model in studying the influences of various parameters on aorta impedance and ventricular-vascular coupling.