Comparison of aortic elasticity determined by cardiovascular magnetic resonance imaging in obese versus lean adults

The vascular properties of large vessels in the obese have not been adequately studied. We used cardiovascular magnetic resonance imaging to quantify the cross-sectional area and elastic properties of the ascending thoracic and abdominal aorta in 21 clinically healthy obese young adult men and 25 men who were age-matched lean controls. Obese subjects had greater maximal cross-sectional area of the ascending thoracic aorta (984 ± 252 vs 786 ± 109 mm², p <0.01) and of the abdominal aorta (415 ± 71 vs 374 ± 51 mm², p <0.05). When indexed for height the differences persisted, but when indexed for body surface area, a significant difference between groups was found only for the maximal abdominal aortic cross-sectional area. The obese subjects also had decreased abdominal aortic elasticity, characterized by 24% lower compliance (0.0017 ± 0.0004 vs 0.0021 ± 0.0005 mm²/kPa/mm, p <0.01), 22% higher stiffness index β (6.0 ± 1.5 vs 4.9 ± 0.7, p <0.005), and 41% greater pressure-strain elastic modulus (72 ± 25 vs 51 ± 9, p <0.005). At the ascending thoracic aorta, only the pressure-strain elastic modulus was different between obese and lean subjects (85 ± 42 vs 65 ± 26 kPa, respectively; p <0.05), corresponding to a 31% difference - but arterial compliance and stiffness index were not significantly different between groups. In clinically healthy young adult obese men, obesity is associated with increased cross-sectional aortic area and decreased aortic elasticity.