Remodelling of Small Resistance Arteries in Essential Hypertension

Abstract

Regardless of the mechanisms that initiate the rise of blood pressure, the development of structural changes in the systemic vasculature is the end result of established hypertension. In essential hypertension, small-artery smooth muscle cells are restructured around a smaller lumen and there is no net growth of the vascular wall, while in some secondary forms of hypertension a hypertrophic remodelling may be detected. Also in type 2 diabetes mellitus a hypertrophic remodelling of subcutaneous small arteries is present. Results from our own group have suggested that indices of small resistance artery structure, such as the tunica media to internal lumen ratio, may have a strong prognostic significance in hypertensive patients, over and above all other known cardiovascular risk factors. Therefore, regression of vascular alterations is an appealing goal of antihypertensive treatment. Different antihypertensive drugs seem to have different effects on vascular structure, both in humans and in animal models of genetic and experimental hypertension. A complete normalisation of the structure of small resistance arteries was demonstrated in hypertensive patients, after prolonged and effective therapy with ACE inhibitors, angiotensin II receptor blockers and calcium antagonists. Few data are available in diabetic hypertensive patients; however, blockade of the renin-angiotensin system seems to be effective in this regard. In conclusion, several pieces of evidence suggest that small resistance artery structure may be considered an intermediate endpoint in the evaluation of the effects of antihypertensive therapy; however, no data are available about the prognostic effect of the regression of vascular structural alterations in hypertension and diabetes.