Ethanol gelation test improved

Peculiarities of blood coagulation disorders in patients with COVID-19

Aim. To study the relationship of hemostatic disorders with inflammation and estimate their role in the course and outcomes of COVID-19. Materials and methods. We examined 215 consecutive patients with moderate and severe forms of acute COVID-19. The patients were on anticoagulants and immunosuppressive drugs. Hemostasis was assessed using the thrombodynamics assay, thromboelastography, fibrinogen and D-dimer levels, prothrombin time, and soluble fibrin-monomer complexes (ethanol gelation test). The hemostatic parameters were correlated with hematological and biochemical tests, including markers of inflammation (C-reactive protein, interleukins 6 and 8), as well as with the disease severity and outcomes. Results. Laboratory signs of coagulopathy were revealed in the vast majority of the cases. Despite the use of low-molecular-weight heparins in the prophylactic and therapeutic doses, coagulopathy in COVID-19 manifested predominantly as hypercoagulability that correlated directly with the systemic inflammation and metabolic changes due to liver and kidney dysfunction. A direct relationship was found between the grade of coagulopathy and the severity of COVID-19, including comorbidities and the mortality. The chronometric hypocoagulability observed in about 1/4 cases was associated with a high level of C-reactive protein, which may decelerate coagulation in vitro and thereby mask the true inflammatory thrombophilia. Persistent hyperfibrinogenemia and high D-dimer in the absence of consumption coagulopathy suggest the predominance of local and/or regional microthrombosis over disseminated intravascular coagulation. Conclusion. The results obtained substantiate the need for laboratory monitoring of hemostasis and active prophylaxis and treatment of thrombotic complications in COVID-19.

Altered platelet and coagulation function in moderate-to-severe COVID-19

To reveal if coagulopathies relate to the course of COVID-19, we examined 255 patients with moderate and severe COVID-19, receiving anticoagulants and immunosuppressive drugs. Coagulopathy manifested predominantly as hypercoagulability that correlated directly with systemic inflammation, disease severity, comorbidities, and mortality risk. The prolonged clotting tests in about ¼ of cases were associated with high levels of C-reactive protein and antiphospholipid antibodies, which impeded coagulation in vitro. Contraction of blood clots was hindered in about ½ of patients, especially in severe and fatal cases, and correlated directly with prothrombotic parameters. A decrease in platelet contractility was due to moderate thrombocytopenia in combination with platelet dysfunction. Clots with impaired contraction were porous, had a low content of compressed polyhedral erythrocytes (polyhedrocytes) and an even distribution of fibrin, suggesting that the uncompacted intravital clots are more obstructive but patients could also be prone to bleeding. The absence of consumption coagulopathy suggests the predominance of local and/or regional microthrombosis rather than disseminated intravascular coagulation. The results obtained (i) confirm the importance of hemostatic disorders in COVID-19 and their relation to systemic inflammation; (ii) justify monitoring of hemostasis, including the kinetics of blood clot contraction; (iii) substantiate the active prophylaxis of thrombotic complications in COVID-19.

[Alterations in the coagulation mechanisms of patients bitten by Bothrops asper (Terciopelo)]

Blood from eighteen patients bitten by B. asper were studied for effects on coagulation. All showed alterations in the levels of fibrinogen and of factors II, V, VIII, IX, X and XI, as well as in anti-thrombin-III and plasminogen. The number of platelets and the concentrations of factors VII and XII did not show significant variations in comparison with the controls. The biological assay of fibrinogen, the quantitation of fibrinogen degradation products and of factor II and the general coagulation tests, such as prothrombin and partial thromboplastin times, showed a good correlation with the severity of the envenomation. In snakebites by B. asper there is a severe hypofibrinogenemia, with fibrin degradation by activation in the fibrinolytic system and with activation and consumption of factor II. Intramuscular emergency treatment with small quantities of antivenom did not prevent the above noted alterations in coagulation.