Key points are not available for this paper at this time.
T he microcirculation is generally taken to include the smallest arteries, the arterioles, capillaries, and venules. 1,2Exchange of gases, nutrients, and metabolites between the blood and tissues occurs almost exclusively in the microcirculation, and adequate perfusion via the microcirculatory network is essential for the integrity of tissue and organ function.Our aim in the present article is to bring together recent clinical and experimental research indicating that inadequate perfusion may underlie much of the tissue and organ dysfunction associated with chronic conditions including hypertension, obesity, and diabetes mellitus.Given the high level of research activity in this field, our review can be neither systematic nor comprehensive.We apologize to the many authors whose important contributions are not acknowledged here; additional references are given in a Data Supplement on the journal's Web site. Tissue Perfusion in HypertensionAn abrupt increase in pressure brings about a rapid and reversible vasoconstriction of small resistance vessels due to their inherent myogenic tone. 4Prolonged elevations of pressure can cause a range of more lasting changes in the microcirculation, 2 of which, remodeling of small arteries and arterioles and rarefaction of arterioles and capillaries, will be considered briefly below. Microvascular RarefactionMicrovascular rarefaction, the reduced number or combined length of small vessels in a given volume of tissue, has been
Lévy et al. (Mon,) studied this question.