On the issue of diagnosing endothelial dysfunction, arterial stiffness and cardiovascular disorders in children with COVID-19 in outpatient settings

Aim - to improve the instrumental diagnostic of endothelial dysfunction by determining arterial stiffness for the timely prevention and correction of cardiovascular disorders in children who have had COVID-19 infection in outpatient settings, and to create an algorithm for managing cardiovascular disorders. Materials and methods. The study group completed by 70 children aged 7-14 years without chronic pathology, who were asymptomatic, mild or moderate in the course of COVID-19 infection with laboratory confirmation of the disease. The comparison group consisted of 30 children with similar age who did not have COVID-19. Structural abnormalities and cardiovascular dysfunction, as well as indicators of arterial stiffness, were investigated by echocardiography. The functional state of the medium-sized vessels’ endothelium was studied by assessing of the blood flow dynamic in the brachial artery and changes in its diameter at rest and during reactive hyperemia. Statistical processing of the obtained data was performed with application package "Statistica 10.0 for Windows" by the method of variation statistics. Results. In children aged 7-14 years who had COVID-19 infection in an outpatient setting, endothelial dysfunction of hypoergic and paradoxical types with impaired arterial elasticity was detected. Indicators that may be markers of impaired vascular stiffness have been identified. The presence of endothelial dysfunction and arterial stiffness are the causes of a number of cardiovascular disorders, even if the infection is mild or moderate. Conclusions. Flow-mediated dilatation of the brachial artery is a noninvasive method for assessing endothelial function and endothelium-dependent vasodilator response to increased blood flow-related stress. Endothelial dysfunction is associated with increasing of vascular stiffness, which was proven in the present study. The determination of flow-mediated dilatation of the brachial artery should be supplemented by the studying of arterial stiffness (systolic and diastolic aortic diameters, distensibility, and arterial tension). Based on results of study, an algorithm for the diagnosis and follow-up of children who have suffered COVID-19 infection in outpatient settings aimed at early detection of cardiorespiratory system disorders, has been developed. The research was carried out in accordance with the principles of the Declaration of Helsinki. Informed consent of the child and child's parents was obtained for the research. No conflict of interest was declared by the authors.