PB1033 - Prolonged coagulation times in Severe fever with thrombocytopenia syndrome virus infection, the indicator of heparin-like effect and increased hemorrhagic risk

Background: Prolonged coagulation times, such as activated partial thromboplastin time (APTT) and thrombin time (TT), are common in patients infected with severe fever with thrombocytopenia syndrome virus (SFTSV), and has been confirmed to be related to patient’s poor outcome by previous studies. However, the reason of coagulation time prolongation in SFTS patient is not clear yet, this also leads to the appropriate intervention uncertain.

Aims: To find out the reason of prolonged coagulation time in patients with SFTSV infection, and whether it predicts hemorrhagic risk or not.

Methods: From April to July 2023, seventy-eight consecutive patients with confirmed SFTSV infection were enrolled in this prospective, single-center, observational study. Several global and specific coagulation parameters of these patients on admission were detected, and the hemorrhagic events during hospitalization and outcomes of them were recorded.

Results: Most of the enrolled patients had prolonged APTT (82.1%), prolonged TT (80.8%), measurable anti-Xa activity (88.5%), normal prothrombin time (83.3%) and intrinsic coagulation factors above hemostatic levels (97.4%). Interestingly, APTT and TT results were significantly positive correlated with the levels of endothelial markers including thrombomodulin (TM) and tissue plasminogen activator-plasminogen activator inhibitor 1 complex (tPAIC) and viral load, respectively. The 28-day mortality of our patients was 29.5%, coagulation times on admission were significantly higher in non-survivors than in survivors, and APTT was independently associated with the hemorrhage of SFTS patients.

Conclusion(s): The prolonged APTT and TT of SFTS patients may mainly due to the heparin-like effect caused by the endothelial glycocalyx degradation, and are associated with increased hemorrhagic risk.