Arterial Stiffness

Abstract

Stiffness of large arteries has been long recognized as a significant determinant of pulse pressure. However, it is only in recent decades, with the accumulation of longitudinal data from large and varied epidemiological studies of morbidity and mortality associated with cardiovascular disease, that it has emerged as an independent predictor of cardiovascular risk. This has generated substantial interest in investigations related to intrinsic causative and associated factors responsible for the alteration of mechanical properties of the arterial wall, with the aim to uncover specific pathways that could be interrogated to prevent or reverse arterial stiffening. Much has been written on the haemodynamic relevance of arterial stiffness in terms of the quantification of pulsatile relationships of blood pressure and flow in conduit arteries. Indeed, much of this early work regarded blood vessels as passive elastic conduits, with the endothelial layer considered as an inactive lining of the lumen and as an interface to flowing blood. However, recent advances in molecular biology and increased technological sophistication for the detection of low concentrations of biochemical compounds have elucidated the highly important regulatory role of the endothelial cell affecting vascular function. These techniques have enabled research into the interaction of the underlying passive mechanical properties of the arterial wall with the active cellular and molecular processes that regulate the local environment of the load-bearing components. This review addresses these emerging concepts.

Keywords: Arterial haemodynamics; Conduit arteries; Endothelial function; Pulse pressure; Pulse wave velocity; Vascular ageing.

Fig. 1

Components of passive and active mechanisms related to arterial stiffness as described in the text and that combine to affect pulse pressure, assuming a regulated stroke volume. The active mechanisms are mainly causative for the development of arterial stiffness and the passive properties are the result of arterial stiffening. There are complex feedback relationships between the components, some of which can be interrogated by altering the cellular signalling pathways. Passive pathways can be affected by alteration of haemodynamic parameters such as wave reflection.