The aging process modifies the distensibility of elastic but not muscular arteries

Aging decreases the distensibility of large elastic arteries; however, the effects of age on the functional parameters of muscular, medium-sized arter ies are not well determined. This study evaluated the consequences of aging on the functional parameters of the carotid and radial arteries in normote nsive men. A total of 62 elderly subjects (aged 74+/-2 years) were compared with 87 young subjects (aged 35+/-3 years). Internal diameter and intima-m edia thickness (IMT) were measured by a high-resolution echo-tracking syste m to calculate distensibility and incremental elastic modulus (Einc). Altho ugh in the normal range, systolic and diastolic blood pressure levels were statistically different in the 2 groups at 128+/-19 and 74+/-13 mm Hg versu s 121+/-27 and 71+/-18 mm Hg in the young and elderly subjects, respectivel y (P<0.05). At the carotid artery level, elderly subjects exhibited a great er IMT (742+/-144 versus 469+/-132 mu m; P<0.01) and internal diameter (706 7+/-828 versus 6062+/-1026 mu m; P<0.01) than young subjects; elderly subje cts also had lower distensibility (12+/-2 versus 21+/-2 kPa(-1) . 10(-3); P <0.01) and higher fine (0.9+/-0.2 versus 0.7+/-0.3 kPa . 10(3); P<0.01), At the radial artery level, both IMT (240+/-42 versus 218+/-51 mu m; P<0.01) and internal diameter (2685+/-432 versus 2491+/-444 mu m; P<0.01) were grea ter in elderly subjects, but no differences in distensibility and fine were observed between the 2 groups. All differences remained significant, even after adjusting for mean blood pressure. These results indicate that the in crease of the internal diameter and IMT observed during the aging process c an have opposite effects on the functional parameters of large elastic or m edium-sized muscular arteries.