Carotid arterial circumferential strain by two-dimensional speckle tracking: a novel parameter of arterial elasticity.

Recently, the development of two-dimensional speckle-tracking (2DST) technology has allowed the direct measurement of the elastic parameters of the carotid arterial wall. The aims of this study were to determine the feasibility of measuring peak circumferential strain (CS) of the carotid arterial wall using 2DST and to compare this value with conventional arterial stiffness parameters in subjects with and without hypertension. The study included 90 healthy subjects and 40 age-and sex-matched patients with hypertension. The short-axis view of the right common carotid artery was recorded. The CS in the posterior region of the carotid artery was calculated by 2DST using special software and corrected by the following equation: ɛ(circ)=ln (systolic blood pressure/diastolic blood pressure)/CS. We simultaneously measured the stiffness index β (β) at the same location and the brachial-ankle pulse wave velocity (baPWV). Sixty randomly selected healthy subjects were used to assess the inter/intra-observer variability of ɛ(circ) and β. In healthy subjects, ɛ(circ) was significantly correlated with β, age and baPWV. These correlations were slightly better than the corresponding correlations of β with age and baPWV. The hypertensive patients had a significantly larger ɛ(circ) than the healthy subjects (0.112 ± 0.074 vs. 0.066 ± 0.029/%, P<0.001). The inter/intra-observer variability for ɛ(circ) was significantly lower than that for β. Our data suggest that the measurement of carotid ɛ(circ) using 2DST is feasible and has better reproducibility than conventional carotid arterial stiffness.