Ac. Pearson et al., TRANSESOPHAGEAL ECHOCARDIOGRAPHIC ASSESSMENT OF THE EFFECTS OF AGE, GENDER, AND HYPERTENSION ON THORACIC AORTIC-WALL SIZE, THICKNESS, AND STIFFNESS, The American heart journal, 128(2), 1994, pp. 344-351
Aging is associated with progressive arterial stiffening and widening
of the pulse pressure, resulting in a high prevalence of systolic hype
rtension. The contribution of increased aortic thickness to this proce
ss and to essential hypertension has been poorly characterized. With t
ransesophageal echocardiography, aortic thickness and diameter can be
measured. Thus, the influence of aging, gender, and hypertension on th
e geometry and stiffness of the descending thoracic aorta in humans ca
n be determined in vivo. In 83 patients undergoing transesophageal ech
ocardiography for clinical indications, recordings of the descending t
horacic aorta were made. There were 53 normotensive subjects (33 men a
nd 20 women, mean age 46 years, range 14 to 79 years) and 25 hypertens
ive subjects (8 men and 17 women, mean age 67 years, range 50 to 80 ye
ars). Measurements of diastolic and systolic aortic thickness and aort
ic diameter were made, and three measures of the elastic properties of
the aorta were calculated: (1) Peterson's elastic modulus, (2) Young'
s modulus, and (3) the stiffness index beta. Aortic thickness averaged
1.1 +/- 0.1 mm in both normotensive men and women. Normotensive women
had a significantly greater thickness/diameter ratio than men (0.06 /- 0.01 vs 0.05 +/- 0.01, p < 0.01), but there were no differences in
stiffness between men and women. Age was highly positively correlated
with thickness (r = 0.74, p < 0.001), diameter (r = 0.67, p < 0.001),
beta (r = 0.79, p < 0.001), Peterson's modulus (r = 0.78, p < 0.001),
and Young's modulus (r = 0.81, p < 0.001). In comparison to the 20 nor
motensive subjects >50 years old with a similar mean age, the hyperten
sive subjects had significantly increased wall thickness (0.14 +/- 0.0
2 vs 0.12 +/- 0.01 mm, p < 0.00004) and beta. In conclusion, aging sig
nificantly increases aortic thickness and stiffness. Women have signif
icantly higher relative aortic wall thickness than men but a similar s
tiffness. Hypertension increases aortic thickness and stiffness. These
data further characterize the aortic geometry and its relation to the
compliance properties of the vessel and suggest fundamental structura
l elements contributing to the vascular effects of aging and systemic
hypertension.