Experimental data on the thermo-mechanical behaviour of human aorta

The effect of temperature on the mechanical response of human arteries still remains largely unknown, mainly due to the lack of appropriate experimental data. However, thermal behaviour of arteries is not a secondary issue in cardiovascular research since many cardiac surgical procedures are performed at non-physiological temperatures. In this work, the influence of temperature on the passive behaviour of human ascending aorta is studied in vitro by means of inflation tests. Two ascending aorta segments were tested in the range 0-200 mmHg at four different temperatures (17, 27, 37, 42 degrees C) and two different axial elongations (lambda=1.0, lambda=1.2). The results show that the combined change of internal pressure and axial elongation can have a dramatic effect on the dilatation coefficient of the arterial wall. The structural stiffness of the arterial wall seems to diminish with temperature, although the change was not significant in the range of temperatures and axial elongations tested.