Abstract
In 72 children and adolescents with arterial hypertension I-II st. after reactive hyperemia using high resolution ultrasound lower rates of increase in the diameter of the brachial artery (BA) and peak blood flow velocity were detected compared to the normotensive control group of children that may be regarded as the depletion of vasodilatation. In children and adolescents with hypertension during occlusion test а more significant decrease of the diameter of BA was revealed, indicating the functional arteriolar hypertonicity, as well as the possible remodeling of arterial vessels. These results should be interpreted as increased tone of BA in children and adolescents with hypertension.