Introduction: In response to atherosclerotic plaque formation, the arterial wall has the potential to remodel. Expansive remodeling was first described as a compensatory mechanism in the coronary arteries, but this phenomenon may differ in other arterial beds due to different vessel wall structure and hemodynamic conditions.
Hypothesis: We tested the hypothesis that symptomatic carotid arteries exhibit expansive remodeling. We further examined whether remodeling pattern is carotid segment specific.
Methods: As part of the Chinese Atherosclerosis Risk Evaluation study, subjects with stroke or TIA and evidence of carotid plaque by ultrasound underwent multicontrast vessel wall magnetic resonance imaging within 2 weeks of onset of symptoms. Axial images of bilateral carotid arteries were acquired and categorized in to common carotid artery (CCA), bifurcation, and internal carotid artery (ICA) segments based on their distance to the flow divider. Average lumen area, total vessel area, and maximum wall thickness (MWT) were measured for each segment. Remodeling patterns were characterized using linear regression analysis of lumen and total vessel areas (dependent variables) with MWT (independent variable) for each segment in the symptomatic side arteries, adjusted for age, sex, height, and squared height.
Results: A total of 418 subjects (mean age: 61.7 years; 28.2% female) with sufficient image quality and coverage were included in this study. The adjusted CCA lumen area was not smaller (P=0.16) with increasing MWT, whereas total vessel area was larger (P= <0.001). The adjusted bifurcation lumen area was smaller with increasing MWT (P= <0.001), while there was no change in total vessel area (P= 0.96). The adjusted ICA lumen area was smaller with increasing MWT (P= <0.001), while total vessel area was larger (P= 0.018).
Conclusions: In this study of subjects with recent stroke or TIA, the remodeling pattern in the CCA segment showed expansive remodeling, but the bifurcation and ICA segments showed constrictive remodeling. The underlying mechanisms, including different hemodynamic conditions and their effects on arterial remodeling, warrant further investigation.