Numerical Prediction of Atherosclerotic Plaque Temperature as a Function of Plaque Size and Composition

Atherosclerotic plaque or cholesterol deposits in arteries with high likelihood of rupture experience an inflammatory cascade that produces a temperature inhomogeneity within the affected artery. As a result, a new and promising method to detect plaque vulnerability is based on the measurement of the arterial wall temperature (AWT). In this paper, the energy equation is solved to determine the plaque temperature distribution on the vessel wall considering blood flow, inflammatory cell density, and plaque size. Two different blood vessel shapes are considered: a stenotic straight artery, and an arterial bend, both with geometry and dimensions that correspond to the human aorta and a human coronary artery, respectively. These vessels were selected because atherosclerotic plaques are commonly encountered in such arteries. The plaque is located in the sites of low shear stress and variations in its volume and cell density are considered. The heat generation in the vulnerable plaque due to macrophage activation in inflammatory processes is taken from the literature. This paper presents steady state calculations. Reynolds numbers of 300 and 500 are used to represent maximum and minimum velocities during the cardiac cycle. Plots of plaque and arterial wall temperature as a function of macrophage concentration, and activation stage are presented; and the maximum plaque temperature is compared with arterial wall temperature values found in the literature.