Hemodynamics and thermal characteristics of a deformable stenosed carotid artery with heat generation: Effect of heart rate, stenotic severity, and wall elasticity

Abstract

The formation of the stenosis in the carotid artery may lead to ischemic stroke, cerebral infarction, and other severe health-related complications. The present study aims to investigate the effects of heart rates on the blood flow dynamics and the heat transfer characteristics of a deformable stenosed carotid artery. This investigation employs an Arbitrary Lagrangian-Eulerian fluid-structure interaction based on the finite element-based solver COMSOL Multiphysics® to model the incompressible continuity, momentum, and energy equations. The model incorporates the elasticity of the carotid artery and the realistic non-Newtonian behavior of pulsatile blood flow. The effect of heart rates (75, 100, 120 bpm), degree of stenosis (25 %, 50 %, 75 %), arterial wall stiffness values (2–3 MPa), and macrophage heat generation (Q̇m = 0.05–0.2 W/mm3) have given insights into pulsatile blood flow dynamics and resultant alterations in thermal characteristics. As heart rates and degree of stenosis increase, the blood supply is severely affected in the internal carotid artery (ICA) connected to cerebral tissues, potentially increasing the risk of ischemic stroke due to inadequate oxygenation. Notably, recirculation zones or vortices form at 100 and 120 bpm heart rates, particularly at 75 % stenotic severity. Higher heart rates correspond to increased wall shear stress in the stenosed ICA region, potentially leading to endothelial damage and vessel rupture, posing significant health risks. At a heart rate of 75 bpm, the temperature increase in macrophages and plaques is 2.07 °C and 0.17 °C, respectively. It highlights the notable impact of heart rate and changes in stenotic severity on temperature distribution, particularly within macrophages in the presence of arterial plaque. These effects are more pronounced with lower heart rates, higher stenosis, and higher heat generation rates associated with arterial plaque. These findings suggest clinical relevance in understanding the complex interplay between heart rates, blood flow dynamics, and thermal characteristics in arterial stenosis scenarios.