EFFECT OF TEMPERATURE ON THE MECHANICAL BEHAVIOR OF THE HUMAN AORTA AND CAROTID ARTERIES

Temperature affects the mechanical behavior of the arteries, a fact that intervenes in their function, both in physiology and in pathological states. The aim of the study is to analyze the mechanical response in the arteries (aorta and carotids) to changes in temperature. MATERIAL AND METHODS The thermo-mechanical behavior of human arteries (26 primitive carotids and 26 thoracic aortas) from cadaveric organ donors has been studied. The tests were carried out in a passive state, without electrical or chemical activation of the vessels. Pressurization tests were carried out at 4 different temperatures (17, 27, 37 and 42ºC) correlating internal pressure-external diameter of the vessels. The thermo-mechanical analysis was evaluated using the pressure-diameter curves at different temperatures, for this the coefficient of thermal expansion (α = (ΔD / D) / ΔT) and the Hayashi stiffness (β), exponential equation (Pressure / Diameter ratio). RESULTS The effect of temperature on arterial behavior is maximum when the curves refer to the initial diameter of the vessel at 0 mmHg for each temperature. At low pressures, the coefficient of dilation is negative, while above a certain threshold pressure (different for each type of artery), the coefficient of dilation becomes positive. CONCLUSIONS The stiffness of the vessels is manifested in the slope of the pressure-diameter curves and decreases with increasing temperature. The coefficient of thermal expansion is a function of the internal pressure to which the arteries are subjected.