FDP Fluctuation in Severe COVID-19 is Associated With the Development of Thrombotic or Bleeding Complications and Systemic Coagulopathy

Purpose: COVID-19 is sometimes associated with coagulation disorders. In such cases, patients developed elevated D‐dimer and fibrin degradation products (FDP) levels, both of which are associated with high risks of thromboembolic complications and poor prognosis. To date, time course changes of FDP values in COVID-19 patients has not been well evaluated. The aim of this study is to evaluate whether FDP fluctuation in COVID-19 patients are associated with systemic coagulopathy. Methods: We retrospectively analyzed the changes in coagulofibrinolytic markers including FDP in 42 COVID-19-ARDS patients. FDP elevation as the fluctuation was defined as follows: 1) FDP>10μg/mL for the first time after admission and 2) 10μg/mL or more elevation after the improvement of the first or subsequent FDP elevations. Results: FDP elevation was observed a total of 30 times in 21 patients (50%). Marked intravascular coagulofibrinolytic activation occurred at the same time as the FDP elevation (soluble fibrin: SF, 27.0 [14.9–80.0] μg/mL; thrombin-antithrombin complex: TAT, 7.5 [2.9–17.8] μg/L; plasmin-α 2 -plasmin inhibitor complex: PIC, 2.4 [1.4–4.2] μg/mL). FDP was elevated in all patients who met sepsis-induced coagulopathy (SIC) or disseminated intravascular coagulation (DIC) diagnosis criteria. Thrombotic or bleeding complications developed in 12 patients (28.6%) and were significantly correlated with FDP elevation ( OR [odds ratio] 4.50, 95% CI [confidence interval] 1.01–20.11, p = 0.049). However, there were no significant differences in coagulofibrinolytic activities between the patients with and without SIC or DIC. Conclusions: Coagulation activation which can lead to the development of systemic coagulopathy such as DIC occurred with FDP fluctuation in severe COVID-19 patients. However, there is a limit of the application of existing DIC and SIC diagnosis criteria to COVID-19.