ИСТИНА

Chronic heart failure (CHF) is one of the most common causes of death worldwide. More than 6 % of deaths in the world are caused by this disease, and the prevalence of the disease, for example in Russia, is approaching to 9 %. This disease is characterized by a decrease in the contractile function of the heart and systemic hypoxia associated with inadequate perfusion of organs and tissues at rest or under physical activity. CHF is accompanied by fluid retention in the body and its accumulation in soft tissues that lead to a decrease in resistance to physical activity, the appearance of edema and shortness of breath. The severity of CHF is determined by the functional class (FC) from I to IV, showing how limited the patient's physical activity is [1]. The state of human organism essentially depends on the aggregation properties of red blood cells (RBC) and platelets as well as RBC deformability, distribution of the cells in sizes and deformability [2]. The importance of monitoring these properties is determined by the need to correct them using various drugs and to estimate the effectiveness of therapy. So far there is no information about the alterations of blood cells properties for different FC of CHF [1]. The goal of this paper is to demonstrate the efficiency of laser-optical methods for estimating the relation of CHF in different FC and blood microrheological properties: RBC aggregation and deformability, platelets aggregation, distribution of RBC in sizes and ability to deform in shear flow. Particular attention is paid to verifying the hypothesis about the interrelation of the width of the distribution of RBC in size and deformability with the decrease in physical activity tolerance [1]. For assessing the blood properties, a comprehensive study was performed for 69 patients suffering from CHF and 18 practically healthy volunteers. All patients were subjected to the test with 6-minute walk to determine the FC of CHF. All participants of the study underwent standard clinical tests and measurements of blood microrheological properties. Blood microrheology was measured in vitro using diffuse light scattering [2], diffractometry, turbidimetry, evaluation of RBC size and deformability distribution parameters using laser ektacytometry on wet blood smears and microscopy of RBC suspensions in microfluidic channels using the algorithms of machine learning [3]. A comprehensive study of microrheological parameters alterations in CHF depending on FC were performed. As a result of this work the microrheological profiles of patients suffering from CHF was obtained. CHF leads to changes in the microrheological properties of the blood: increased aggregation of erythrocytes and platelets, as well as a decrease in the deformability of erythrocytes. The degree of changes in microrheological parameters is associated with the FC of CHF. The used set of laser-optical methods are an effective tool for in vitro monitoring disorders of blood properties in CHF. This work was supported by the grant of Interdisciplinary Scientific and Educational School of MSU «Photonic and Quantum technologies. Digital medicine» (grant No. 23-Ш06-03).