Arteriolar rarefaction in the conjunctiva of human essential hypertensives

Blood rheology in men with essential hypertension and capillary rarefaction

“…1,3 Lack of capillaries may also be involved in the increased total peripheral resistance in essential hypertension as reduction in capillary density per volume of tissue occurs. 4 Rarefaction of capillaries stolic pressure, higher blood viscosity at low shear, higher P-selectin levels, higher erythrocyte and leukocyte filterability rates, and higher erythrocyte aggregation indexes (all P Ͻ 0.01). In contrast, patients with greater skin capillary density had a greater plasma viscosity (P Ͻ 0.05).…”

Impaired microvascular dilatation and capillary rarefaction in young adults with a predisposition to high blood pressure.

“…The characteristic increase in peripheral vascular resistance in essential hypertension is, therefore, likely to reflect structural or functional changes in these microvessels (4). Structural abnormalities in vessels of hypertensive patients include decreased luminal diameter, predominantly in larger arterioles (5,6), but also in capillaries (7,8), and a reduction in the density of vessels per volume of tissue (known as rarefaction), which occurs predominantly in the smallest vessels (2,(7)(8)(9)(10)(11)(12)(13). Functional abnormalities of microvessels in established essential hypertension include reduced capillary blood flow in the basal state (14) and reduced vasodilatation induced by heating (15).…”

Elements of Vascular Mechanics

“…A well analyzed territory is the retinal arteriolar network. Rarefaction, that is, the decreased number of parallelly connected resistance arteries seems to be an important contributor to morphologically elevated vascular resistance in chronic hypertension (Harper 1978). The "chaos theory" seems to be one fruitful approach to describe general laws of geometric vascular network development (Herman 2001).…”

“…Even more important than changes in segmental geometry, can be the network alterations. Rarefaction and course deviations in hypertension also increase local resistance (Greene 1989, Harper 1978, Nadasy 2000, 2010b, Prasad 1995.…”