P2.9 A NOVEL SPECKLE TRACKING TECHNIQUE FOR INVESTIGATING REGIONAL MOTION OF THE CAROTID WALL: SPATIO-TEMPORAL VARIATION IN DISTENSION ASSOCIATES WITH PRESENCE OF CALCIFIED PLAQUE

Abstract

Background: Arterial calcification may lead to regional variation in distension imposing stresses on the arterial wall that predispose to plaque rupture. The objective of this study was to use a novel speckle tracking method to investigate regional motion of the carotid wall and to determine whether this relates to subclinical disease. Methods and results: Measurements were obtained on 256 subjects from the Twins UK cohort (mean ± SD age 62±10.2 years). The left carotid was imaged for an assessment of plaque and calcification. Speckle-tracking was then used to measure regional circumferential strain of the left common carotid in 6 separate 60° segments of the circumference of the arterial wall in a plaque free plane of the common carotid approximately 1 cm proximal to the bifurcation. Regional variation in circumferential strain around the circumference of the arterial wall was characterized by the standard deviation of circumferential strain and that of the time from onset of systole to peak circumferential strain in each segment. Spatio-temporal variation in circumferential strain characterized by variation in the time to peak circumferential strain was associated with age and presence of calcified plaque (regression coefficients 0.73 units/year and 14.2 increase for presence of calcified plaque, each P<0.001) independent of other confounding factors and of other measures of arterial wall damage such as carotid intima-media thickening, carotid distensibility and carotid-femoral pulse wave velocity. Conclusion: Arterial ageing and calcification are associated with spatio-temporal variation in distension of the carotid artery.