Comparative analysis of hemostasis system state indicators in severe COVID-19

Abstract

Introduction. Clinical experience in managing patients with a new coronavirus infection caused by the SARS-CoV-2 allowed to identify specific hemostasis disorders, and enables to introduce the concept of COVID-associated coagulopathy. The aim of the study was to assess the direction of coagulogram parameter changes, whole blood clotting parameters and characteristics of platelet and plasma hemostasis in patients with severe COVID-19. Materials and methods. The parameters of the hemostasis system were assessed using venous blood of 12 patients with severe COVID-19 and 16 healthy volunteers. The whole blood clotting process was investigated by low-frequency piezothromboelastography. The platelet count and indicators of spontaneous and ADP-induced platelet aggregation were estimated with the help of a laser platelet aggregation analyzer. Fibrinolytic activity of plasma, plasminogen activity, content of fibrinogen, D-dimer, PTT, APTT, PTI and INR were assessed. Results. An increased level of fibrinogen, a 6-fold increased D-dimer level, and increased PTT were found in patients with severe COVID-19. The patient platelets count was reduced by 51 % (p <0.05), spontaneous platelet aggregation remained at nearly normal level. Almost complete inhibition of ADP-induced platelet reactivity and inhibition of XIIa-dependent fibrinolysis was revealed, despite an increased by 19.3 % (p <0.05) plasminogen activity. Parameters of the whole blood coagulation process pointed a pronounced activation of platelet hemostasis, a significant intensification of the polymerization stage of clot formation and an increased intensity of clot lysis and retraction. Conclusion. The significant increase of D-dimer level and paradoxical inhibition of plasma fibrinolytic activity revealed by test of XIIa-dependent fibrinolysis (in contrast to the increased intensity of clot lysis when assessing the coagulation of whole blood) indicate the complex pathogenic mechanisms of coagulopathy caused by SARS-CoV-2 infection, and the involvement of blood cells and the vascular wall in the process of pathological thrombus formation.