Abstract 18357: Vulnerable Carotid Plaque is Characterized by a Difference in Mobility Between Plaque Core and Cap
Vulnerable carotid plaque can cause an ischemic stroke, but its detection is elusive. The aim was to study the mechanical properties of carotid plaques using ultrasound speckle tracking.
Methods: Study population consisted of 61 (aged 53-89, median 68) patients with carotid atherosclerosis: 21 with acute atherothrombotic stroke (7 day after stroke onset) and 40 without symptoms. The stroke subtype was classified according to TOAST criteria. In total, 21 symptomatic and 47 asymptomatic plaques were analyzed. For plaque-free area (PFA) and for each plaque, maximum circumferential and longitudinal strains (S[[Unable to Display Character: с]], Sl) and strain rates (SRc SRl) were measured (with separate measurements for plaque cap, core and base). Plaque characteristics (echogenicity, length, degree of stenosis) were also assessed.
Results: plaque and PFA differed in Sl and SRl values, whereas no difference was observed for Sc and SRc (Table 1). Sc and SRc for cap and core of echolucent plaques were higher as compared with hyperechogenic ones (Table 1). For echolucent plaques a significant difference in Sc and SRc was also detected between segments, and the highest values were observed in cap (Table 1).
However, for symptomatic plaques, Sc and SRc of plaque core were significantly higher than values for cap (Table 1). Plaque internal motion coefficient Pim=(core SRc - cap SRc)/base SRc was developed to quantify the relative motion of different plaque segments against each other. According to ROC curve analysis, plaques with Pim>0.09 are associated with ischemic event (sensitivity 76%, specificity 65%, AUC=0.76, p<0.001). Logistic regression confirmed that Pim>0,09 is an independent predictor of plaque vulnerability, OR=5.26, 95% CI 1.4-19.3 controlling for age, gender, plaque length, degree of stenosis and echogenicity.
Conclusions: Echolucent plaques are more mobile than hyperechogenic ones. In symptomatic plaques, the increased deformation of inner core may be linked with plaque vulnerability.
- © 2013 by American Heart Association, Inc.