No abstract

No abstract

The novel coronavirus disease of 2019 (COVID-19) pandemic, as declared by the World Health Organization, is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV2). 1,2 Cardiovascular disease and, in particular, venous thromboembolism (VTE), has emerged as an important consideration in the management of hospitalized patients with COVID-19. The diagnosis of VTE using standardized objective testing is problematic in these patients, given the risk of infecting non-COVID-19 hospitalized patients and hospital personnel, coupled with the usual challenges of performing diagnostic testing in critically ill patients.Early reports suggest a high incidence of VTE in hospitalized COVID-19 patients, particularly those with severe illness, that is similar to the high VTE rates observed in patients with other viral pneumonias, including severe acute respiratory syndrome

Objectives: Recent studies have reported a high prevalence of thrombotic events in coronavirus disease 2019. However, the significance of thromboembolic complications has not been widely appreciated. The purpose of this review is to provide current knowledge of this serious problem. Design: Narrative review. Data Sources: Online search of published medical literature through PubMed using the term "COVID-19, " "SARS, " "acute respiratory distress syndrome, " "coronavirus, " "coagulopathy, " "thrombus, " and "anticoagulants. " Study Selection and Data Extraction: Articles were chosen for inclusion based on their relevance to coagulopathy and thrombosis in coronavirus disease 2019, and anticoagulant therapy. Reference lists were reviewed to identify additional relevant articles. Data Synthesis: Coronavirus disease 2019 is associated with a strikingly high prevalence of coagulopathy and venous thromboembolism that may contribute to respiratory deterioration. Monitoring coagulation variables is important, as abnormal coagulation tests are related to adverse outcomes and may necessitate adjuvant antithrombotic interventions. In the initial phase of the infection, d-dimer and fibrinogen levels are increased, while activated partial prothrombin time, prothrombin time, and platelet counts are often relatively normal. Increased d-dimer levels three times the upper limit of normal may trigger screening for venous thromboembolism. In all hospitalized patients, thromboprophylaxis using low-molecular-weight heparin is currently recommended. The etiology of the procoagulant responses is complex and thought to be a result of specific interactions between host defense mechanisms and the coagulation system. Although the coagulopathy is reminiscent of disseminated intravascular coagulation and thrombotic microangiopathy, it has features that are markedly distinct from these entities. Conclusions: Severe acute respiratory syndrome coronavirus 2/ coronavirus disease 2019 frequently induces hypercoagulability with both microangiopathy and local thrombus formation, and a systemic coagulation defect that leads to large vessel thrombosis and major thromboembolic complications, including pulmonary embolism in critically ill hospitalized patients. d-dimers and fibrinogen levels should be monitored, and all hospitalized patients should undergo thromboembolism prophylaxis with an increase in therapeutic anticoagulation in certain clinical situations.

The COVID‐19 pandemic has become an urgent issue in every country. Based on recent reports, the most severely ill patients present with coagulopathy, and disseminated intravascular coagulation (DIC)‐like massive intravascular clot formation is frequently seen in this cohort. Therefore, coagulation tests may be considered useful to discriminate severe cases of COVID‐19. The clinical presentation of COVID‐19‐associated coagulopathy is organ dysfunction primarily, whereas hemorrhagic events are less frequent. Changes in hemostatic biomarkers represented by increase in D‐dimer and fibrin/fibrinogen degradation products indicate the essence of coagulopathy is massive fibrin formation. In comparison with bacterial‐sepsis‐associated coagulopathy/DIC, prolongation of prothrombin time, and activated partial thromboplastin time, and decrease in antithrombin activity is less frequent and thrombocytopenia is relatively uncommon in COVID‐19. The mechanisms of the coagulopathy are not fully elucidated, however. It is speculated that the dysregulated immune responses orchestrated by inflammatory cytokines, lymphocyte cell death, hypoxia, and endothelial damage are involved. Bleeding tendency is uncommon, but the incidence of thrombosis in COVID‐19 and the adequacy of current recommendations regarding standard venous thromboembolic dosing are uncertain.

The JAAM scoring system has an acceptable property for the diagnosis of DIC. The scoring system identified most of the patients diagnosed by the JMHW and ISTH criteria. Revised JAAM DIC criteria preserved all properties of the original criteria for DIC diagnosis. The revised scoring system can be useful for selecting DIC patients for early treatment in a critical care setting.

Thrombotic complications and coagulopathy frequently occur in COVID-19. However, the characteristics of COVID-19-associated coagulopathy (CAC) are distinct from those seen with bacterial sepsis-induced coagulopathy (SIC) and disseminated intravascular coagulation (DIC), with CAC usually showing increased D-dimer and fibrinogen levels but initially minimal abnormalities in prothrombin time and platelet count. Venous thromboembolism and arterial thrombosis are more frequent in CAC compared to SIC/DIC. Clinical and laboratory features of CAC overlap somewhat with a hemophagocytic syndrome, antiphospholipid syndrome, and thrombotic microangiopathy. We summarize the key characteristics of representative coagulopathies, discussing similarities and differences so as to define the unique character of CAC.

Background COVID-19-associated coagulopathy (CAC) characterized by the elevated D-dimer without remarkable changes of other global coagulation markers is associated with various thrombotic complications and disease severity. The purpose of this review is to elucidate the pathophysiology of this unique coagulopathy. Methods The authors performed online search of published medical literature through PubMed using the MeSH (Medical Subject Headings) term "COVID-19," "SARS-CoV-2," "coronavirus," "coagulopathy," and "thrombus." Then, selected 51 articles that closely relevant to coagulopathy in COVID-19. Results The primary targets of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are the pneumocytes, immune cells, and vascular endothelial cells. The alveolar damage and the pulmonary microvascular thrombosis are the major causes of acute lung injury in COVID-19. The endotheliopathy that occurs is due to direct SARS-CoV-2 infection and activation of other pathways that include the immune system and thromboinflammatory responses leading to what is termed CAC. As a result, both microvascular and macrovascular thrombotic events occur in arterial, capillary, venule, and large vein vascular beds to produce multiorgan dysfunction and thrombotic complications. In addition to the endothelial damage, SARS-CoV-2 also can cause vasculitis and presents as a systemic inflammatory vascular disease. Clinical management of COVID-19 includes anticoagulation but novel therapies for endotheliopathy, hypercoagulability, and vasculitis are needed. Conclusion The endotheliopathy due to direct endothelial infection with SARS-COV-2 and the indirect damage caused by inflammation play the predominant role in the development of CAC. The intensive control of thromboinflammation is necessary to improve the outcome of this highly detrimental contagious disease.