Background and Purpose: Atherosclerosis in the carotid artery is a significant cause of stroke. The purpose of this study is to evaluate hemodynamic parameters using in vitro carotid artery models and how geometrical features affect the development and progression of carotid atherosclerosis.
Methods: Nine polydimethylsiloxane (PDMS) channels mimicking carotid arteries, including three healthy models with different bifurcation angles (35.8°, 55.8°, and 75.8°) and six diseased models with various stenosis severities (35%, 65%, and 85%) based on plaque locations (low body and high apical types), were fabricated. The working fluid to match the refractive index of PDMS channels was prepared. The particle image velocimetry experiments were conducted to compare the hemodynamic effects on the various arterial models.
Results: The ratio of outlet flow rate significantly decreased in the severe (85%) stenosis of the low body and high apical types (11.7% and 14.2%, respectively) compared to mild (35%) and moderate (65%) stenoses. The proportion of low wall shear stress (WSS; < 1 Pa) in the outer wall of internal carotid artery with bifurcation angle of 35.8° (63%) is larger than those with bifurcation angle of 55.8° (48%) and 75.8° (33%). As the severity of stenosis increases, the jet flow appears in the narrowed areas in both low body and high apical types, and consequently, the WSS increases. In addition, the recirculating flow is observed at the post-stenosis region.
Conclusions: The carotid artery geometry including bifurcation angle, plaque location, and stenosis severity alters flow patterns, emphasizing comprehensive hemodynamic studies for atherosclerosis.