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Research and Practice in Thrombosis and Haemostasis Conference ; 6(Supplement 1), 2022.
Article in English | EMBASE | ID: covidwho-2128257


Background: Coronavirus disease-2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV- 2), has resulted in an ongoing world-wide pandemic. Vaccination is the key countermeasure of the COVID-19 pandemic. Data on the efficacy, safety and immunogenicity of COVID-19 vaccination in patients with hemophilia -and in particular in those with HIV -are still scarce. Aim(s): The aim of our study was to characterize the immunogenicity and biomarkers of coagulation and endothelial perturbation after mRNA-COVID- 19 vaccination in HIV-positive hemophilic patients. Method(s): We collected blood from 24 adult HIV-positive hemophilic patients followed at our centre (19 with hemophilia A, 5 with hemophilia B) before and two weeks after the administration of the complete vaccination schedule with mRNA-1273 (Moderna Biotech). Most patients had severe hemophilia (n = 21). We measured antibodies to SARS-CoV- 2 spike protein by Elecsys (Roche) to assess immunogenicity and we evaluated protein C, VWF, D-dimer plasma levels as biomarkers of coagulation and endothelial perturbation. Anti-Platelet Factor 4 (PF4) antibodies were also measured. Result(s): Before vaccination, three patients out of 24 showed anti-Spike IgG levels >0.8 U/ml (cut-off value). Two weeks after completing the vaccination schedule, all patients had high values of anti-Spike IgG (min-max 2,387-12,500 U/ml). Mean (standard deviation) basal values of protein C, VWF and D-dimer (106 +/- 21%, 171 +/- 45%, 593 +/- 692 ng/ml respectively) were not significantly different from values measured two weeks after the second dose of vaccine (103 +/- 20%, 162 +/- 43%, 583 +/- 531 ng/ml). Anti-PF4 antibodies were detected in three patients with no associated clinical manifestations. None of the patients reported bleeding in the site of inoculation nor serious adverse events after the vaccination. Conclusion(s): Since immune abnormalities can occur in HIV-positive patients, it is important to collect data on COVID-19 vaccination immunogenicity. We demonstrated that hemophilic HIV-positive patients have a normal antibody response against SARS-CoV- 2 spike protein. In addition, mRNA-1273 had no effect on coagulation and endothelial perturbation.

Research and Practice in Thrombosis and Haemostasis Conference ; 6(Supplement 1), 2022.
Article in English | EMBASE | ID: covidwho-2128125


Background: A novel acquired coagulopathy characterized by a severe procoagulant imbalance is common in COVID-19 patients and is associated with the clinical severity of the disease. Aim(s): Our study aims to elucidate the underlying mechanisms of coagulation activation in COVID-19 patients. Method(s): Symptomatic COVID-19 patients during Milan first wave were consecutively enrolled and stratified into 3 groups based on the intensity of care: Low, requiring only high-flow oxygen by nasal cannula;intermediate, requiring continuous positive airway pressure;high, requiring mechanical ventilation. Blood samples were tested for markers of activation of the intrinsic pathway (FXIa, FXIIa) together with its physiologic inhibitor (C1-inhibitor), of the extrinsic pathway (FVIIa), of global activation of the coagulation cascade (D-dimer, FDP, FM) and of fibrinolysis (plasminogen, t-PA, alpha2-antiplasmin, PAI-1). Result(s): 111 patients were included: 26 at low, 42 intermediate and 43 high care-intensity. Median age was 59 +/- 12 (34 patients >65 years);32 patients (29%) developed a venous thrombosis and 12 (11%) died (Table). Median D-dimer, FDP and FM plasma levels were higher in COVID-19 patients compared to controls, with a gradient of increase across the three care intensities, while all the fibrinolytic pathway parameters were in the normal range. Median plasma levels of FVIIa were lower in COVID-19 patients (27.5 mU/ml) than in controls (40.1 mU/ml) while median plasma levels of FXIIa and FXIa were higher in COVID-19 patients (11.2 and 11.3 mU/ml) than in controls (7.2 and 5.5 mU/ml), with a gradient of increase across the three care intensities. C1-inhibitor plasma levels were above the normal range in all the 3 COVID-19 patients' groups (Figure). Conclusion(s): Our study showed a prevalent activation of the contact pathway over the extrinsic pathway of the coagulation cascade in COVID-19 patients, which is proportional to the clinical severity of the infection, opening the possibility for targeted anticoagulant therapies. (Table Presented).

Research and Practice in Thrombosis and Haemostasis ; 5(SUPPL 2), 2021.
Article in English | EMBASE | ID: covidwho-1508945


Background : Covid-19 infection is associated with a widespread global activation of coagulation and affected patients are at an increased risk of thrombosis. Aims : Heparin therapy is effective in various setting in preventing thromboembolic complications and aim of this study was to assess heparin response in COVID-19 patients through anti-FXa test. Methods : In 52 patients, M:F ratio 59:41, median age 59 years old, admitted in different intensity of care units of our hospital, treated with different regimens of heparin (100 U/kg every 24 h in low intensity care, 70 U/kg every 12 h in intermediate intensity care and 100 U/kg every 12 h in intensive care unit), anti-FXa levels were measured immediately before and 3 h after subcutaneous enoxaparin administration. On the same samples thrombin generation tests were performed. Results : Patients treated with 100 U/kg every 24 h and 70 U/ kg every 12 h had median anti-FXa basal levels in the prophylactic range, respectively 0.18 and 0.22 U/ml, while patients treated with 100 U/kg every 12 h were in the anticoagulant range (0.37 U/ ml). Despite heparin therapy thrombin generation was elevated in COVID-19 patients, indicating a high level of coagulation activation. Conclusions : In conclusion we demonstrated that the biological response to enoxaparin in COVID-19 patients is in the expected range using anti-FXa assay and patients are not resistant to heparin therapy.