Regional aortic function is correlated with intima-media thickness-insights from three-dimensional echocardiography

Abstract

Background: Thickening of arterial intima and the presence of atherosclerotic plaques may influence vessel pulsation by increasing the wall stiffness. There are no data available concerning regional changes in aortic elasticity in relation with local wall thickness and the magnitude of atherosclerosis.

Methods: The study group comprised 48 patients (33 men, age 54 +/- 11 years) referred for transesophageal echocardiography. Reconstruction of 2-cm segments of aorta was divided by coaxial planes into 4 longitudinal sections. Thereafter, diastolic and systolic radius, thickness of atherosclerotic plaques, and intima-media thickness (IMT) in each section were measured. The relative change in regional aortic lumen (pulsation) was measured and regional beta-index was calculated. In total, 192 aortic sections were analyzed.

Results: The volume of the examined sections of the aortic segments ranged from 0.6 to 4.1 cm3 (mean 1.6 +/- 0.7 cm3) in systole and from 0.5 to 3.7 cm3 (mean 1.4 +/- 0.7 cm3) in diastole. The pulsation of the aortic sections varied from 0.04 to 0.78 cm3 (mean 0.21 +/- 0.13 cm3), which constituted 1% to 21% (mean 6 +/- 4%) of the section volume. The thickness of atherosclerotic plaques in the studied aortic sections ranged from 0.03 to 1.87 mm (mean 0.31 +/- 0.26 mm) and IMT was within the range 1.28 to 3.61 mm (mean 1.87 +/- 0.39 mm). The regional beta-index of the individual section ranged from 1.6 to 97.1 (mean 12.5 +/- 14.6). The regional beta-index was statistically significantly dependent on the IMT (r = 0.43, P < .001), but not on the thickness of atherosclerotic plaques (P = .96). The variability of regional beta-index, defined as the difference between the highest and the lowest beta-index in the sections of the same aortic segment, ranged from 1.7 to 83.1 (mean 20.0 +/- 20.7) and was borderline correlated with the IMT (r = 0.26, P = .07), but not with the thickness of atherosclerotic plaques (P = .87).

Conclusions: Three-dimensional echocardiography facilitates quantitative analysis of aortic wall stiffness and regional beta-index measurements. The local aortic wall beta-index and its regional variability is dependent on IMT, but not on the thickness of atherosclerotic plaques.