Arterial stiffening: opposing effects of age- and hypertension-associated structural changes.

This article reviews the effects of aging and hypertension on geometrical (lumen and arterial wall thickness) and functional (distensibility) properties of large and medium-sized arteries in humans. Several clinical and animal studies show that arterial wall hypertrophy does not increase the elastic modulus of the arterial wall material during sustained essential hypertension. The structural changes associated with either hypertension or aging have opposing effects on arterial distensibility, under similar transmural conditions: the former increasing it, the latter decreasing it. Thus, hypertension cannot be assimilated to aging. The structural and functional changes of the arterial wall material that are associated with the hypertension-induced hypertrophy could be a means by which medium-sized arteries maintain their distensibility characteristics despite increased distending pressure, and large arteries compensate for the age-induced decrease in arterial compliance.