Structural alterations of the retinal microcirculation in the "prehypertensive" high-normal blood pressure state

The high-normal blood pressure (also known as prehypertension) is a clinical condition characterized by an increased cardiovascular risk as well as by the presence of target organ damage. This include an increased left ventricular mass, an endothelial dysfunction and an early renal functional and structural damage. Whether this is the case also for alterations of retinal vessels network, which are frequently detectable in established hypertension, is still largey undefined. The present paper, after discussing the main characteristics of the high-normal blood pressure state, will review the different approaches used throughout the years for assessing retinal microcirculatory network. Data collected by our group in subjects with high normal blood pressure will be also discussed, showing that arterial venular ratio values are reduced in this individuals with high-normal blood pressure and more so in established hypertension. These data indicate that retinal microvascular alterations 1) are of early appearance in the clinical course of hypertension and 2) are of frequent detection in the high-normal blood pressure state. The possible hemodynamic and non-hemodynamic mechanisms resposible for these structural alteations of the retinal microcirculation will be also discussed.