Mechanisms and consequences of large artery rigidity

Abstract

In this review paper, the classical and more recently described mechanisms responsible for the structural and functional characteristics of large artery rigidity are described. Mostly important, these characteristics appear to be nonspecific to the primary disease process involved in arterial hypertension, diabetes mellitus, dyslipidemia, congestive heart failure, chronic uremia, and perhaps senescence, including vascular dementia. Nonspecific in terms of aetiology, the vasculopathy encountered in these diseases exhibits common structural and functional abnormalities. The identification of such abnormalities could well become the target of potent nonpharmacological and (or) pharmacological interventions capable of preventing or retarding morbidity and mortality. The structural characteristics responsible for large artery rigidity include smooth muscle cell hypertrophy, matrix collagen deposition, and recently described, dysfunction in proteoglycan metabolism. Functional abnormalities, such as bradykinin-dependent hyper-reactivity of smooth muscle cells and vasa vasorum microcirculation network disturbances, also appear to alter aortic wall rigidity. The physiopathology of target organ damage is then revisited, based on endothelial dysfunction, documented in large and resistance arteries, as well as in microcirculation networks, where altered permeability to macromolecules leads to interstitial matrix disorganization and cell damage. The clinical evaluation of large artery rigidity is described, and one of the noninvasive methods, evaluation of pulse-wave velocity, is validated in normal conditions and in disease processes. Finally, nonpharmacological and pharmacological therapeutic measures are presented, and includes physical exercise to reduce insulin resistance, and renin–angiotensin-II–aldosterone modulators.Key words: large artery compliance, aortic structure, collagen, elastin, proteoglycans, vascular smooth muscle cells, vasa vasorum, target organ damage, pulse wave velocity, vascular pharmacology.