ABSTRACT
After the vaccination campaign initiation in Europe and the UK, reports of rare cases of atypical thrombosis, including sinus vein thrombosis and splanchnic venous thrombosis, began to appear in association with the use of AstraZeneca (ChAdOx1) and J&J/Janssen adenovirus vector vaccines. The syndrome called VITT (vaccine-induced immune thrombotic thrombocytopenia) is manifested as thrombosis simultaneously with decreased platelet count, significantly increased D-dimer levels and detected anti-factor 4 platelet (PF4) antibodies. We present a detailed review on the epidemiology, pathogenesis, clinical picture, diagnostics and treatment of VITT, which by its nature is an immune complication similar to the processes occurring in heparin-induced thrombocytopenia (HIT). All international and national organizations and regulatory authorities, including experts in the field of thrombosis and hemostasis and the VITT expert council recommend continuing the prompt mass vaccination against COVID-19 as the only method able to reduce the incidence of severe cases, stop the spread of COVID-19 infection and emergence of new dangerous mutations in the viral genome. Failure to vaccinate poses an incomparably greater risk of fatal thrombotic and inflammatory complications associated with infections, compared with the risks of extremely rare adverse events that can occur after vaccination. It should be noted that information on VITT, described as a sporadic phenomenon of abnormal immune response to some variants of vaccines against COVID-19, cannot be translated to other vaccines (including those registered in the Russian Federation) and, moreover, cannot be a reason to refuse their administration. © 2021 Obstetrics, Gynecology and Reproduction. All rights reserved.
ABSTRACT
The rate of thrombosis and disseminated intravascular coagulation (DIC) has been increasing in COVID-19 patients. Key features related to such condition include minimal or no risk of bleeding, moderate thrombocytopenia, high plasma fibrinogen as well as increased complement components level in the areas of thrombotic microangiopathy. The clinical picture is not typical for classic DIC. This review systematizes the pathogenetic mechanisms of hypercoagulation in sepsis and its extreme forms in patients with COVID-19. The latter consist of the thrombosis-related immune mechanisms, the complement activation, the macrophage activation syndrome, the formation of antiphospholipid antibodies, the hyperferritinemia, and the dysregulation of the renin-angiotensin system. Taking into consideration the pathogenetic mechanisms, the biomarkers had been identified related to the prognosis of the disease development. Patients with pre-existing cardiovascular disease and other risk factors, including obesity, diabetes, hypertension, and aging pose the peak risk of dying from COVID-19. We also summarize new data on platelet and endothelial dysfunction, immunothrombosis, and, as a result, thrombotic storm as essential components of COVID-19 severe features. © 2021 Obstetrics, Gynecology and Reproduction. All rights reserved.
ABSTRACT
Numerous studies have proven a close relationship between inflammatory diseases and the state of hypercoagulability. In fact, thromboembolic complications represent one of the main causes of disability and mortality in acute and chronic inflammatory diseases, cancer and obstetric complications. Despite this, the processes of hemostasis and immune responses have long been considered separately;currently, work is underway to identify the molecular basis for a relationship between such systems. It has been identified that various pro-inflammatory stimuli are capable of triggering a coagulation cascade, which in turn modulates inflammatory responses. Neutrophil extracellular traps (NETs) are the networks of histones of extracellular DNA generated by neutrophils in response to inflammatory stimuli. The hemostasis is activated against infection in order to minimize the spread of infection and, if possible, inactivate the infectious agent. Another molecular network is based on fibrin. Over the last 10 years, there has been accumulated a whole body of evidence that NETs and fibrin are able to form a united network within a thrombus, stabilizing each other. Similarities and molecular cross-reactions are also present in the processes of fibrinolysis and lysis of NETs. Both NETs and von Willebrand factor (vWF) are involved in thrombosis as well as inflammation. During the development of these conditions, a series of events occurs in the microvascular network, including endothelial activation, NETs formation, vWF secretion, adhesion, aggregation, and activation of blood cells. The activity of vWF multimers is regulated by the specific metalloproteinase ADAMTS-13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13). Studies have shown that interactions between NETs and vWF can lead to arterial and venous thrombosis and inflammation. In addition, the contents released from activated neutrophils or NETs result in decreased ADAMTS-13 activity, which can occur in both thrombotic microangiopathies and acute ischemic stroke. Recently, NETs have been envisioned as a cause of endothelial damage and immunothrombosis in COVID-19. In addition, vWF and ADAMTS-13 levels predict COVID-19 mortality. In this review, we summarize the biological characteristics and interactions of NETs, vWF, and ADAMTS-13, the effect of NETs on hemostasis regulation and discuss their role in thrombotic conditions, sepsis, COVID-19, and obstetric complications.
ABSTRACT
Our knowledge regarding chemical structure and properties of heparin and its derivatives, including biological properties in blood plasma, on the cell surface and while interacting with receptors, has been progressively growing. New insights are followed by the expansion of therapeutic opportunities and indications for the use of heparins. There are prerequisites for the creation of new generation drugs with modified properties that reduce a bleeding risk while applied for a non-anticoagulant goal. The non-anticoagulant heparin properties allow to consider it as a candidate for pathogenetic treatment of patients with COVID-19. This review focuses on the anticoagulant and non-anticoagulant heparin properties as well as the underlying molecular mechanisms.
ABSTRACT
Recently, it has been increasingly apparent that sepsis and septic shock become a pressing issue. Over the last decade, incidence rate of sepsis in obstetrics and gynecology has been increased by more than 2-fold. Here we review clinical forms of septic conditions, risk factors, pathogenesis of sepsis and septic shock, as well as major pathogens resulting in septic conditions. Special attention is paid to neonatal sepsis. The relationship between septic shock and viral infections is considered in the context of the novel coronavirus infection (COVID-19) pandemic caused by SARS-CoV-2. Impaired hemostasis is discussed in patients with septic shock, including those with disseminated intravascular coagulation (DIC). An importance of assessing ADAMTS-13 level to refine disease prognosis is discussed.
ABSTRACT
Dear editors of Obstetrics, Gynecology and Reproduction Journal! Due to the particular urgency of the problem of managing patients with a new coronavirus infection (COVID-19), we are sending a letter outlining our position on this issue.