ИСТИНА

Nowadays, cardiovascular diseases are the leading cause of death globally. The ability of RBC to aggregate in blood flow strongly influences blood viscosity and, as a result, blood microcirculation and state of human organism. Therefore, it is important to monitor aggregation properties of RBC and blood microcirculation during treatment of different pathologies. In this work to assess aggregation properties in vitro, we used two optical techniques – laser aggregometry and optical trap and manipulation techniques [1, 2]. For assessing parameters of blood microcirculation in vivo we used vital digital capillaroscope technique [2, 3]. The aim of this work to compare the aggregation parameters measured in vitro with parameters of blood flow obtained in vivo in patients with cardiovascular diseases. Laser aggregometer RheoScan was used on whole blood samples to measure microrheologic parameters of RBC aggregation (aggregation index, characteristic time of aggregates formation). Laser tweezers were used to trap and manipulate individual red blood cells with a highly focused laser beam in order to measure the time and force of their spontaneous aggregation – interaction of single cells. Digital capillaroscope Kapillaroskan-1 was used to conduct in vivo measurements of blood flow velocity, presence and absence of aggregates and stasis in capillary blood flow. Overall, 88 patients with cardiovascular diseases were enrolled in the study. They were divided into two groups. First group enrolled only patients with hypertension without cardiovascular complications (n = 48) and second group included patients (n = 40) with established coronary heart disease. To present our results we have divided patients into various subgroups by parameters measured by Kapillaroskan-1. For example, we analyzed separately patients who had their capillary blood flow less than 800 µm/s and people who had it greater. Our results demonstrate that the first subgroup has the aggregation time 24±6% smaller than the second one. Patients suffering from arterial hypertension have their aggregation force greater by 17±9% compared to coronary heart disease patients with the same capillary blood flow. Our results clearly demonstrate the possibility of using laser aggregometry and optical trapping for estimating the alterations of aggregation parameters. Alterations of RBC aggregation parameters measured in vitro can be used to evaluate the alterations of vital capillary blood flow parameters in human body. This work is supported by Russian Science Foundation (Grant N 18-15-00422).