[Relation between cardiac hypertrophy and changes in the large arterial trunks. Role of the renin-angiotensin system]

The raised mean arterial pressure observed in hypertension increases the stress on the walls of large arteries by increasing the mechanical forces to which they are submitted. Cardiac and arterial wall hypertrophy seem to be adaptive mechanisms tending to reduce the stress in each musculo-elastic unit of the cardiovascular system. However, this adaptation only partially explains the development of cardiovascular hypertrophy. Cardiovascular changes are sometimes observed before the increase in blood pressure, as in normotensive children of hypertensive parents. Moreover, a dissociation has been shown between the antihypertensive effects of different antihypertensive agents. For the same reduction in mean arterial pressure, some drugs are associated with a greater regression in these changes than others. At present, it is acknowledged that other factors than mean arterial pressure may cause these changes. For example, the pulse pressure is a major factor, independent of mean arterial pressure, in developing cardiovascular hypertrophy. The activation of hormonal systems, especially the angiotensin converting enzyme system, influences cardiovascular structure. Therefore, hyperactivity of the renin-angiotensin system may stimulate the growth factor responsible for cardiac and arterial hypertrophy.