The Microcirculation in Hypertension: Which Are the Resistance Vessels?

Hypertensive subjects show microvascular changes that include structural decreases in the arteriolar lumen, increases in wall-to-lumen ratio, and decreases in the number of arterioles. In experimental renal hypertension, arteriolar vasoconstriction is first increased and then diminishes as structural elevations in vascular resistance develop. The small arteries may contribute significantly to the elevated vascular resistance. Whether these changes have a primary or secondary role in hypertension is still open to question.