Changes in the Fibrinolytic System of Patients Infected with Severe Acute Respiratory Syndrome Coronavirus 2

Introduction: In this study, coagulation and fibrinolysis parameters and their association with disease severity were investigated in coronavirus disease (COVID-19) patients. Materials and Methods: COVID-19 patients (n=446) admitted to our institute between February 21, 2021 and March 17, 2022, were recruited. Clinical data and staging were collected from all patients. Blood samples were collected and analyzed for several parameters of fibrinolysis and coagulation, including alpha-2-antiplasmin(α2AP) and plasminogen, thrombin activatable fibrinolysis inhibitor (TAFI), tissue plasminogen activator (tPA), plasminogen activator inhibitor-1 (PAI-1), D dimer, and fibrinogen levels. Results: The TAFI, fibrinogen, and tPA levels were significantly higher in participants who died compared to that of patients who recovered (P<0.001). However, PAI-1, tPA, and TAFI were significantly higher in patients admitted to the ICU than those of the healthy controls (P<0.001 for PAI-1 and tPA; P=0.0331 for TAFI). Our results showed that stage C and D COVID-19 patients had significantly higher levels of PAI-1 (P = 0.003). Furthermore, the stage D COVID-19 patients had significantly higher tPA and TAFI values (P=0.003). Conclusions: Hypofibrinolysis was the most prevalent condition among patients with severe COVID-19. In this study, several coagulation markers were elevated, making them suitable prognostic markers for hypofibrinolysis.

Figure 1. Plasma levels of different coagulation factors in COVID-19 patients. Plasma isolated from patients that had died due to COVID-19 and those recovering from the disease (top panel).