Arterial aging: pathophysiological principles

Abstract

Abstract:In the nineteenth century, prior to the introduction of the cuff sphygmomanometer, arteriosclerosis (stiffening of arteries) was recognized by clinicians and by life insurance companies as an indicator of vascular aging and cardiovascular risk, even in asymptomatic individuals. Through the twentieth century, views on aging came to focus on values of systolic and diastolic pressure and on obstructive atherosclerotic disease. Such focus deflected attention from the primary aging change which occurs in all societies, and is represented by stiffening and dilation of the proximal aorta. This review emphasizes the cushioning function of elastic arteries -principally the aorta -and how in youth this results in optimal interaction with the heart, and optimal steady flow through peripheral resistance vessels. Aortic stiffening with age is principally due to fatigue and fracture of elastin lamellae, with transfer of stress to stiffer collagenous components. Stiffening increases left ventricular load and myocardial blood requirement, but limits the capacity for blood supply during diastole. Consequences are cardiac failure and predisposition to ischaemia. The second, under-appreciated effect of aortic stiffening is transmission of flow pulsations downstream into vasodilated organs, principally brain and kidney, where pulsatile energy is dissipated and fragile microvessels are damaged. This accounts for micro infarcts and microhaemorrhages, with specialized cell damage, cognitive decline and renal failure. The aging process can be best monitored by change in the arterial pressure wave rather than by reliance on the cuff sphygmomanometer. This reintroduces the approaches by clinicians and life insurance examiners of the nineteenth century, endorses modern treatments for established disease, and holds the promise of detecting premature arterial degeneration, and better applying lifestyle measures and vasoactive medications to modify the aging process.

The time course of salt-induced hypertension, and why it matters

“…High salt intake has been associated with stiffening of the large central arteries in both animals 99 and humans. 100,101 If a component of this were due to structural changes that were not rapidly reversible (that is, similar to those that have been associated with hypertension and aging [102][103][104] ), this could contribute to the effect of salt to cause a slow and irreversible increase in blood pressure.…”

Distensibility of the Aorta and Carotid Artery and Left Ventricular Mass From Childhood to Early Adulthood

“…3,27 However, it has been estimated that it takes 30 years until elastin breakdown becomes relevant. 28 Therefore, other mechanisms related to growth may play a role in the age-related changes seen in the present study. As demonstrated by the data from this study and the cross-sectional Young Finns Study (Figure 2A), the decline in carotid distensibility seems rather linear between ages 11 and 39 years.…”

Using Korotkoff Sounds to Detect the Degree of Vascular Compliance in Different Age Groups

“…The study shows that in the older individuals, the mean amplitude is 6.02±3.20 mm, which is 4.37mm less than that of the younger individuals (p=0.001) who have an average amplitude of 10.39±5.13 mm. This occurs as a result of the phenomenon of arteriosclerosis which occurs in the ageing arterial wall [2]. Arteriosclerosis leads to a decrease in elasticity of the wall thus making it less compliant, and hence, being able to flutter less.…”

“…If it is possible to ascertain a correlation between an increase in pulse pressure and an expected decrease in amplitude of Korotkoff sounds -both of which can be attributed to decreased vascular compliance that occurs with ageing [2], then it would have prognostic implications in situations where there is a pathological alteration in the blood vessel and its properties.…”