Background Severe coronavirus disease 2019 (COVID‐19) is characterized by an increased risk of thromboembolic events, with evidence of microthrombosis in the lungs of deceased patients. Objectives To investigate the mechanism of microthrombosis in COVID‐19 progression. Patients/Methods We assessed von Willebrand factor (VWF) antigen (VWF:Ag), VWF ristocetin‐cofactor (VWF:RCo), VWF multimers, VWF propeptide (VWFpp), and ADAMTS13 activity in a cross‐sectional study of 50 patients stratified according to their admission to three different intensity of care units: low (requiring high‐flow nasal cannula oxygenation, n = 14), intermediate (requiring continuous positive airway pressure devices, n = 17), and high (requiring mechanical ventilation, n = 19). Results Median VWF:Ag, VWF:RCo, and VWFpp levels were markedly elevated in COVID‐19 patients and increased with intensity of care, with VWF:Ag being 268, 386, and 476 IU/dL; VWF:RCo 216, 334, and 388 IU/dL; and VWFpp 156, 172, and 192 IU/dL in patients at low, intermediate, and high intensity of care, respectively. Conversely, the high‐to‐low molecular‐weight VWF multimers ratios progressively decreased with increasing intensity of care, as well as median ADAMTS13 activity levels, which ranged from 82 IU/dL for patients at low intensity of care to 62 and 55 IU/dL for those at intermediate and high intensity of care. Conclusions We found a significant alteration of the VWF‐ADAMTS13 axis in COVID‐19 patients, with an elevated VWF:Ag to ADAMTS13 activity ratio that was strongly associated with disease severity. Such an imbalance enhances the hypercoagulable state of COVID‐19 patients and their risk of microthrombosis.

IntroductionImpairment of fibrinolysis during sepsis is associated with worse outcome. Early identification of this condition could be of interest. The aim of this study was to evaluate whether a modified point-of-care viscoelastic hemostatic assay can detect sepsis-induced impairment of fibrinolysis and to correlate impaired fibrinolysis with morbidity and mortality.MethodsThis single center observational prospective pilot study was performed in an adult Intensive Care Unit (ICU) of a tertiary academic hospital. Forty consecutive patients admitted to the ICU with severe sepsis or septic shock were included. Forty healthy individuals served as controls. We modified conventional kaolin activated thromboelastography (TEG) adding urokinase to improve assessment of fibrinolysis in real time (UK-TEG). TEG, UK-TEG, plasminogen activator inhibitor (PAI)-1, thrombin-activatable fibrinolysis inhibitor (TAFI), d-dimer, DIC scores and morbidity (rated with the SOFA score) were measured upon ICU admission. Logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (95% CIs) of mortality at ICU discharge.ResultsUK-TEG revealed a greater impairment of fibrinolysis in sepsis patients compared to healthy individuals confirmed by PAI-1. TAFI was not different between sepsis patients and healthy individuals. 18/40 sepsis patients had fibrinolysis impaired according to UK-TEG and showed higher SOFA score (8 (6–13) vs 5 (4–7), p = 0.03), higher mortality (39% vs 5%, p = 0.01) and greater markers of cellular damage (lactate levels, LDH and bilirubin). Mortality at ICU discharge was predicted by the degree of fibrinolysis impairment measured by UK-TEG Ly30 (%) parameter (OR 0.95, 95% CI 0.93–0.98, p = 0.003).ConclusionsSepsis-induced impairment of fibrinolysis detected at UK-TEG was associated with increased markers of cellular damage, morbidity and mortality.

The novel plasma-derived FV concentrate was effective to correct "in vitro" severe FV deficiency in patients. The optimal FV concentration to fully normalize both global clotting times and thrombin generation parameters using the novel plasma-derived FV concentrate was 25 IU/dL.

Summary. Background: Patients with inflammatory bowel disease (IBD) have an increased prevalence of thromboembolic events. The pathogenetic mechanisms of these events include reduced fibrinolysis, which may be caused by antibodies to tissue-type plasminogen activator (t-PA). Objectives: To evaluate anti-t-PA antibodies in patients with IBD, considering clinical, biochemical and functional characteristics. Patients and methods: We immunoenzymatically measured anti-t-PA antibodies in plasma from 97 consecutive IBD patients and 97 ageand sex-matched healthy controls. We also assessed the antibody interactions with different epitopes of t-PA, the antibody inhibition on t-PA activity and the correlations with clinical features and other serum antibodies. Results: IBD patients had higher median anti-t-PA antibody levels (5.4 U mL )1 vs. 4.0 U mL )1; P < 0.0001): 18 patients were above the 95th percentile of the controls (OR 5.3; 95% CI 1.7-16.3; P < 0.003), and the six with a history of thrombosis tended to have high levels (6.9 U mL )1). Anti-t-PA antibody levels did not correlate with IBD type, activity, location or treatment, or with age, sex, acute-phase reactants or other antibodies. The anti-t-PA antibodies were frequently IgG1 and bound t-PA in fluid phase; they recognized the catalytic domain in 10 patients and the kringle-2 domain in six. The IgG fraction from the three patients with the highest anti-t-PA levels slightly reduced t-PA activity in vitro. Conclusions: The prevalence of anti-t-PA antibodies is high in IBD patients. By binding the catalytic or kringle-2 domains of t-PA, these antibodies could lead to hypofibrinolysis and contribute to the prothrombotic state of IBD.

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Veno-venous Extracorporeal Membrane Oxygenation (ECMO) is used in the most severe cases of respiratory failure and further exacerbates the patients’ inflammatory status. Antithrombin is supplemented during ECMO for its anticoagulant effects, but it also deploys anti-inflammatory properties. In this pre-specified ancillary study of the GATRA trial [NCT03208270] we aimed to evaluate the relationship between antithrombin and inflammation during ECMO. Forty-six patients were included in the study, 23 were randomized to receive antithrombin to maintain a level of 80–120% (study group) and 23 were randomized not to be supplemented (control group). Anticoagulation was provided in both groups with heparin infusion. Six cytokines were measured at 5 timepoints from prior to ECMO start to 7 days after ECMO removal. Cytokines decreased during the study but overall were not very different in the two groups. Testing the interaction between the study group and timepoints suggests that the administration of antithrombin led to a more rapid decrease over time of IL-6, IL-1β, TNF-⍺ and Pro-ADM. Plasma levels of antithrombin (either endogenous or exogenous) were negatively associated with all cytokines. Inflammation decreases during ECMO but a causal effect of antithrombin administration on the reduction of inflammation (and its clinical relevance) must be confirmed by appropriately powered studies.

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Introduction The original one‐stage clotting assay is still the most widely used method to measure Factor VIII clotting activity (FVIII:C) in patients with haemophilia A (HA), although the use of chromogenic assays is increasing significantly. Aim Evaluation of the analytical performance and diagnostic accuracy of BIOPHEN™ FVIII:C (HYPHEN BioMed, Neuville‐sur‐Oise, France) assay on Sysmex CS‐2400 (Sysmex, Kobe, Japan) analyser. Methods Sixty patients with haemophilia A (HA; any severity) and 120 healthy Italian subjects were included. All the assays were performed on citrate platelet‐poor plasmas stored at −80°C. Chromogenic BIOPHEN™ FVIII:C was compared with the one‐stage assay using Actin FS and Factor VIII deficient plasma (Siemens Healthcare Diagnostics, Marburg, Germany) on Sysmex CS‐2400 and with another chromogenic automated assay (COAMATIC™ Factor VIII, CHROMOGENIX on ACL TOP analyzer; Instrumentation Laboratory, Milan, Italy). Results Intra‐assay and inter‐assay coefficient of variation were <6%. Linearity was good up to 1/128 dilution (r = 0.99); mean recovery was 91.7% and limit of detection was 0.2%. BIOPHEN™ FVIII:C assay showed a good correlation and diagnostic agreement with the chromogenic COAMATIC™ assay: the Spearmen's Rank correlation coefficient was 0.98 and the inter‐rate agreement K Cohen coefficient was 0.61. The K coefficient was 0.91 when BIOPHEN™ FVIII:C was compared with the historical classification of the patients, demonstrating an optimal diagnostic accuracy in HA. Conclusions BIOPHEN™ FVIII:C showed good analytical performance and diagnostic accuracy and could be considered suitable for the introduction in routine analytical panel of coagulation for the diagnosis of HA patients.