Carotid plaque, arterial stiffness gradient, and remodeling in hypertension

The analysis of plaque mechanics along the longitudinal axis (bending strain) may provide useful information because repetitive bending strain of an atherosclerotic plaque can fatigue the wall material and result in plaque rupture. Whether essential hypertension is associated with a specific pattern of bending strain has not yet been determined. The study included 92 patients with an atherosclerotic plaque on the common carotid artery: 66 patients with essential hypertension, either treated or not, and 26 normotensive patients. A novel noninvasive echotracking system (ArtLab; Esaote, The Netherlands) was used to measure intima-media thickness, diameter, and distensibility at 128 sites on a 4-cm-long carotid segment. Carotid plaque was either less elastic than adjacent carotid artery (inward strain) or more elastic (outward strain). Inward strain was more frequently associated with an inward plaque remodeling, whereas an outward strain was more frequently associated with an outer remodeling. In multivariate logistic regression analysis, patients with essential hypertension were more likely to exhibit an inward strain of carotid plaque (odds ratio=6.9 [1.4 to 34.9]; P<0.02), independently of 2 factors favoring inward strain: an outer remodeling (odds ratio=4.6 [1.7 to 13.4]; P<0.005) and the absence of renin-angiotensin system blockers (odds ratio=4.8 [1.1 to 20.4]; P<0.05). In conclusion, arterial wall material of hypertensive patients was less elastic at the site of the plaque than upstream, and carotid was inwardly strained in the zone affected by plaque. This may generate a high level of stress concentrations and fatigue, exposing the plaque to a greater risk of rupture.