Background: Accumulating evidence indicates towards an association between SARS-CoV-2 infection and procoagulatory state in blood. Thromboelastographic investigations are useful point-of-care devices to assess coagulation and fibrinolysis.
Objectives: We investigated the hypothesis that the procoagulatory state in COVID-19 patients is caused by impaired fibrinolysis system.
Methods: COVID-19 patients admitted to normal wards or to the intensive care unit (ICU) were included in the study. Whole blood samples were investigated by thromboelastography. Additionally, global parameters of coagulation and factors of fibrinolysis as plasminogen activator inhibitor-1 (PAI-1), tissue plasminogen activator (tPA), plasminogen activity and alpha 2-antiplasmin (A2AP) were determined.
Results and conclusion: A significantly increased lysis-resistance and a significantly longer time of lysis after adding tissue plasminogen activator was observed in blood samples from ICU COVID-19 patients compared to controls (maximal lysis: 3.25% ± 0.56 vs. 6.20% ± 0.89, p=0.0127; lysis time: 365.7s ± 44.6 vs. 193.2s ± 16.3, p=0.0014). PAI-1 activity was significantly higher in plasma samples of ICU COVID-19 patients (PAI-1: 4.92U/ml ± 0.91 vs. 1.28U/ml ± 0.33, p=0.001). Interestingly, a positively correlation between the activity of PAI-1 and the lysis time of the formed clot (r=0.7015, p=0.0006) was observed.
Our data suggest that severe SARS-CoV-2 infection is associated with impaired fibrinolytic activity in blood, where fibrinolytic inhibitors are elevated leading to an increased resistance to clot lysis. Future clinical studies should address the contribution of the fibrinolysis system to the procoagulatory state in blood of COVID-19 patients and investigate potential therapeutic targets in this system.