Age-related changes in aortic arch geometry: relationship with proximal aortic function and left ventricular mass and remodeling

Abstract

Objectives: We sought to define age-related geometric changes of the aortic arch and determine their relationship to central aortic stiffness and left ventricular (LV) remodeling.

Background: The proximal aorta has been shown to thicken, enlarge in diameter, and lengthen with aging in humans. However, no systematic study has described age-related longitudinal and transversal remodeling of the aortic arch and their relationship with LV mass and remodeling.

Methods: We studied 100 subjects (55 women, 45 men, average age 46 ± 16 years) free of overt cardiovascular disease using magnetic resonance imaging to determine aortic arch geometry (length, diameters, height, width, and curvature), aortic arch function (local aortic distensibility and arch pulse wave velocity [PWV]), and LV volumes and mass. Radial tonometry was used to calculate central blood pressure.

Results: Aortic diameters and arch length increased significantly with age. The ascending aorta length increased most, with age leading to aortic arch widening and decreased curvature. These geometric changes of the aortic arch were significantly related to decreased ascending aortic distensibility, increased aortic arch PWV (p < 0.001), and increased central blood pressures (p < 0.001). Increased ascending aortic diameter, lengthening, and decreased curvature of the aortic arch (unfolding) were all significantly associated with increased LV mass and concentric remodeling independently of age, sex, body size, and central blood pressure (p < 0.01).

Conclusions: Age-related unfolding of the aortic arch is related to increased proximal aortic stiffness in individuals without cardiovascular disease and associated with increased LV mass and mass-to-volume ratio independent of age, body size, central pressure, and cardiovascular risk factors.

Figure 1. Aortic Arch Geometry assessment with MRI

Sagittal oblique view of the thoracic aorta using a spin echo black blood MRI acquisition illustrating aortic measurements: L1: length of the aortic arch, AC: average arch curvature, H: arch height, W: arch width, Ant: anterior arch width, Post: posterior arch width. L2: length of the descending aorta.

Figure 2. Effect of Age on Measures of Aortic Geometry

Relationship with age of : Panel A: ascending and descending proximal and distal aortic diameters. Panel B: aortic arch and descending aortic lengths. Panel C: breakdown of local aortic arch dimensions. Panel D: average aortic arch curvature. Age group sample size: 20–29 years: n=20, 30–39: n=16, 40–49:n=26, 50–59:n=15, 60–69:n=13, >70:n=10. Statistical significance for trend across age categories : *p<0.0001, †p<0.01, ‡p=0.09.

Figure 3. Relationship between Aortic Stiffness and Aortic Geometry

Distribution of the following indices of aortic arch geometry by quartiles of aortic arch PWV: Panel A: aortic arch length (mm), Panel B: aortic arch curvature (mm⁻¹), Panel C: aortic arch width (mm). p: significance level for ANOVA F-test.

Figure 4. Relationships of Aortic Geometry to Left Ventricular Mass Index and Age

Relationship of aortic arch length (Panel A) and aortic arch curvature (Panel B) according to quartiles of LV mass index and to age group: <40, 40–60 and >60 years.