HYPERTENSION AND THE MICROCIRCULATION - A BRIEF OVERVIEW OF EXPERIMENTAL STUDIES

Purpose: To review experimental findings on the importance of the microcirculation in hypertension. Results of data analysis: A significant part of the increase in vascular resistance found in hypertension involves alterations in the arteriolar network. Changes in vascular reactivity and amplification of normal microvascular autoregulatory loops are among the mechanisms involved in these microvascular alterations. Depending on the organ and the type of hypertension, different types of changes have been observed, including (1) changes in resting arteriolar diameter and increased tone, either throughout the arteriolar network or localized to certain arteriolar segments; (2) temporary closure of a significant fraction of the terminal arteriolar bed; and (3) degenerative processes in terminal arterioles and capillaries inducing anatomical rarefaction of the microvessels. Conclusions: Microvascular changes are responsible for only a portion of the increased resistance but they are extremely important in the global understanding of the hypertensive process, as they are potentially responsible for tissue damage and may be related to the increased risk of organ failure in hypertension.