Аннотация:Arterial hypertension (AH), also known as high blood pressure, is a long-termmedical condition in which the blood pressure in the arteries is persistentlyelevated. AH can lead to severe alterations of vitally important systems of thehuman organism including the cardiovascular system and resulting in damageto blood vessels and capillaries, impairment of blood hemorheology. Enhancedaggregation of erythrocytes and platelets is one of key factors, which determinesthe blood flow and thereby affects the blood rheology. The ability oferythrocytes to deform in shear flow conditions is second major property thataffects blood microcirculation. Alterations in these properties lead to changingthe blood viscosity and, as a consequence, to changes in capillary blood flow.This can lead to significant impairment of blood function, which increases a riskof occurrence of vascular concomitant diseases, and even the mortality. In thiswork, complex studies of the factors determining the capillary blood flow inpatients suffering from AH were conducted by optical methods. Laseraggregometer and diffractometer RheoScan AnD-300 (Rheomeditech, Korea)was used to conduct in vitro measurements of aggregation and deformabilitycharacteristics of the erythrocytes on ensembles of cells. Double-channeledoptical tweezers were used for in vitro measuring the aggregation speed as wellas interaction forces during erythrocyte doublet formation on cellular level. To visualize and quantitatively evaluate the capillary blood flow in vivo noninvasive capillaroscopy measurements in the nailfold vessels were conducted. Itwas shown that in AH-patients, the ability of erythrocytes to deform is slightlyreduced while the aggregation speed and forces of the cells interaction aresignificantly increased relative to the control group. The blood microcirculationin nailfold capillaries is impaired as well. Acknowledgment: Supported by thegrant of the Russian Scientific Foundation # 18-15-00422.