Haemostatic differences between SARS-CoV- 2 PCR-positive and -negative patients at the time of hospital admission

Background: Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV- 2) is associated with a prothrombotic phenotype with an increased risk for thrombosis. Aim(s): To investigate whether COVID-19 is associated with changes in coagulation parameters upon presentation at the emergency department and whether these changes are associated with the development of thrombotic complications in patients with SARS-CoV- 2 infection. Method(s): A single centre, cross-sectional cohort study: The MArkers in COVID-19 And Relations to Outcomes in the Netherlands (MACARON) study was conducted. All patients suspected of SARS-CoV- 2 infection referred to the emergency department of the Meander Medical Center between March-May 2020 were included. 519 patients (26% PCR positive, median age 66 (range 19-97 years), 52.2% male) were included from whom an oro-and nasopharyngeal swab was obtained for detection of SARS-CoV- 2 by polymerase chain reaction (PCR). Blood samples for laboratory analysis were obtained from all patients. Thrombosis was defined as a clinical diagnosis of venous thromboembolism or atherothrombotic event based upon radiology and laboratory results. Result(s): SARS-CoV- 2 PCR positive patients had increased fibrinogen levels (5.41 g/L vs. 4.21 g/L, p < 0.001) and decreased levels of protein C (85.1% vs. 96.1%, p < 0.001) and alpha2-macroglobulin (4.41 muM vs. 5.11 muM, p < 0.001) compared to the PCR negative patients. In addition, we found more acquired activated protein C resistance in PCR positive patients. Furthermore, we found that elevated levels of factor VIII (208% vs. 162%, p = 0.028) and von Willebrand Factor (208% vs. 186%, p = 0.038) and decreased ADAMTS-13 levels (597 ng/ml vs. 691 ng/ml, p < 0.001) were associated with increased occurrence of thrombosis in PCR positive patients (thrombosis vs. non-thrombosis). Conclusion(s): We found that PCR positive patients had a more pronounced prothrombotic phenotype with endothelial activation upon hospital admission showing that coagulation tests may be considered useful to discriminate severe cases of COVID-19 at risk for thrombosis.

Lupus anticoagulant as predictor for thrombosis in critically ill COVID-19 patients: A retrospective cohort study

Background: Thrombosis is a frequent and severe complication in COVID-19 patients admitted to the intensive care unit (ICU). Lupus anticoagulant (LA) is a strong acquired risk factor for thrombosis in various diseases and is frequently observed in COVID-19 patients. Whether LA is associated with thrombosis in patients with severe COVID-19 is currently unclear. Aim(s): To investigate if LA is associated with thrombosis in critically ill COVID-19 patients. Method(s): The presence of LA and other antiphospholipid antibodies was assessed in COVID-19 patients admitted to the ICU. Informed consent was obtained by an opt-out approach and the study was approved by the local medical ethical committee. LA was determined with dilute Russell's Viper Venom Time (dRVVT) and LA-sensitive Activated Partial Thromboplastin Time (aPTT) reagents. Statistical analysis to study the association of LA and other antiphospholipid antibodies with thrombosis occurrence was performed using logistic regression. Result(s): Out of 169 COVID-19 patients, 116 (69%) tested positive for at least one antiphospholipid antibody upon admission to the ICU. Forty (24%) patients tested positive for LA;of whom 29 (17%) tested positive with a dRVVT, 19 (11%) tested positive with an LA-sensitive aPTT and eight (5%) tested positive on both tests. Fifty-eight (34%) patients developed thrombosis after ICU admission. The odds ratio (OR) for thrombosis in patients with LA based on a dRVVT was 2.4 (95%-CI: 1.1-5.4), which increased to 5.1 (95%-CI: 1.7-15.4) in patients on or below the median age of this study population (64 years). LA-positivity based on a dRVVT or LA-sensitive aPTT was only associated with thrombosis in patients younger than 65 years (OR: 4.2, 95%-CI: 1.5-11.7). Conclusion(s): LA on admission is strongly associated with thrombosis in critically ill COVID-19 patients, especially in patients <65 years of age.

Hyperresponsive platelets and a reduced platelet granule release capacity is associated with severity of COVID-19 symptoms and with increased mortality

Background: COVID-19 is often associated with mild thrombocytopenia and increased platelet reactivity. The aim of the current study was to investigate if platelets of COVID-19 patients were primed to hyper-reactive platelets and if the circulating platelets become exhausted during COVID-19 disease. Aim(s): To investigate if platelets of COVID-19 patients were primed to hyper-reactive platelets and if the circulating platelets become exhausted during COVID-19 disease. Method(s): Time dependent platelet activation is studied in whole blood by monitoring the ATP release kinetics from platelets upon stimulation with PAR1 receptor agonist in 41 critical ill COVID-19 patients, 47 COVID-19 patients who were hospitalized but were not critically ill and 30 healthy controls. Result(s): Our study demonstrated that platelets of critical ill COVID-19 patients were hyper-responsive and had a reduced platelet granule release capacity, probably due to exhaustion. The platelet reactivity time of COVID-19 patients admitted to the critical care unit was 2-fold reduced if compared with the response time of healthy controls and 1.6-fold reduced if compared with non-critical COVID-19 patients. Platelet responsiveness was also associated (spearman r;p-value) with D-dimer (0.5;<001), CRP (0.57;<001) and neutrophil-lymphocyte ratio (0.54;<001). Moreover, an increased platelet responsiveness and reduced platelet granule release capacity were associated with an increased mortality (OR;95% CI: 18.8;6.1-57.9 and 4.9;1.5-16.3, respectively). These relationships remained significant after adjustment for age, sex, D-dimer, CRP and neutrophil-lymphocyte ratio. Conclusion(s): Our findings show that platelet hyper-reactivity and reduced platelet granule release capacity were associated with increased critical illness and increased mortality of COVID-19 patients.

Coagulation parameters predict COVID-19- related thrombosis in a neural network with a positive predictive value of 98%

Background: Thrombosis is a major complication of a SARS-CoV- 2 infection. COVID-19 patients show changes in coagulation factor levels and functional coagulation tests that indicate an important role for the coagulation system in the pathogenesis of COVID-19. However, the multifactorial nature of thrombosis complicates the prediction of thrombotic events based on a single hemostatic variable. Aim(s): We used a neural network to predict future COVID-19- related thrombosis. Method(s): We developed neural networks for the prediction of thrombosis in COVID-19 patients based on several dedicated coagulation parameters and general laboratory variables measured in plasma samples of 133 COVID-19 patients collected at the time of hospital admission (cohort 1). The neural network was validated in a second cohort of 16 COVID-19 patients admitted to the intensive care unit (cohort 2). In cohort 1 and 2, 19 and 7 patients respectively suffered from thrombosis during their hospital stay. Result(s): The neural network predicts COVID-19- related thrombosis based on C-reactive protein (relative importance 14%), sex (10%), thrombin generation (TG) time-to- tail (10%), alpha2-macroglobulin (9%), TG curve width (9%), thrombin-alpha2- macroglobulin complexes (9%), plasmin generation lag time (8%), anti-SARS- CoV- 2 serum IgM (8%), TG lag time (7%), TG time-to- peak (7%), thrombin-antithrombin complexes (5%), and age (5%). In developmental cohort 1, the neural network identified future thrombosis in COVID-19 patients with a positive predictive value of respectively 98%. The neural network accurately ruled out thrombosis in COVID-19 patients as the negative predictive value of the neural network was 86%. In validation cohort 2, the positive predictive value of the neural network was 100%, and a negative predictive value of 66%. Conclusion(s): We developed a neural network that can accurately predict the occurrence of COVID-19- related thrombosis and is a promising algorithm to apply to other COVID-19 patient cohorts. The prediction of COVID-19 related thrombosis potentially can give clinicians the opportunity to increase anticoagulant therapy in high risk patients.

Haemostatic differences between SARS-CoV-2 PCR-positive and negative patients at the time of hospital admission.

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is associated with thrombosis. We conducted a cohort study of consecutive patients, suspected of SARS-CoV-2 infection presented to the emergency department. We investigated haemostatic differences between SARS-CoV-2 PCR positive and negative patients, with dedicated coagulation analysis. The 519 included patients had a median age of 66 years, and 52.5% of the patients were male. Twenty-six percent of the patients were PCR-positive for SARS-CoV-2.PCR positive patients had increased levels of fibrinogen and (active) von Willebrand Factor (VWF) and decreased levels of protein C and α2-macroglobulin compared to the PCR negative patients. In addition, we found acquired activated protein C resistance in PCR positive patients. Furthermore, we found that elevated levels of factor VIII and VWF and decreased levels of ADAMTS-13 were associated with an increased incidence of thrombosis in PCR positive patients. In conclusion, we found that PCR positive patients had a pronounced prothrombotic phenotype, mainly due to an increase of endothelial activation upon admission to the hospital. These findings show that coagulation tests may be considered useful to discriminate severe cases of COVID-19 at risk for thrombosis.