PB0060 - Hypercoagulability in COVID-19: Is there an Antiphospholipid Syndrome?

Background: Hypercoagulability has been established in COVID-19 and has been linked to thrombotic risk. The existence of an antiphospholipid (aPL) syndrome in COVID-19 remains controversial.

Aims: Determine if markers of aPL syndrome are elevated in COVID-19 and associated with hypercoagulability and in-hospital clinical events.

Methods: Blood, urine, clinical data, and outcomes were analyzed in patients hospitalized with COVID-19 (n=100) enrolled in the IRB approved TARGET-COVID study and in healthy subjects (n=131). aPL syndrome was assessed using using lupus anticoagulant assays (dRVVT and Hex LA, Precision BioLogic Inc.); aPL antibody (APA) profiling (IgA,IgM,IgG) against aB2GP1, anticardiolipin (aCL), and anti-phosphotidyl serine (aPS) assays (Corgenix). Hypercoagulability, and coagulation markers (D-Dimer, Factor-V, VIII, XII, and Prekalikrein) were assessed using thromboelastography (TEG-6s), ELISA, and standard coagulation assays, respectively.

Results: Mean age was 59±19 yrs.; predominately African American (65%), with a high prevalence of hypertension (74%), obesity (53%), and diabetes (45%). LA positivity was observed in 2%; and 32%, 23%, and 9% by aB2GP1, aCL, and aPS antibody testing, respectively (Figure 1). Hypercoagulability defined by platelet-fibrin clot strength (MA≥68mm) was observed in 62% of the total group and was not associated with LA or APA positivity. Patients had lower FV, FXII, PK activity vs. healthy subjects (p < 0.05 for all). D-dimer was higher in patients with aPL’s vs. negative patients (p=0.03) but was not associated with thrombotic events (21% vs 16%). Patients with positive aPS antibodies had higher mortality than aPS negative, and aCL positive, and aB2GP1 positive patients (44% vs 18%, 10%, 7%; p< 0.05) respectively.

Conclusion(s): Based on LA assay, aPL syndrome is infrequent in COVID-19. However, there is a high prevalence of aPL antibodies that correlate with D-dimer with the greatest prevalence observed for aB2GP1. aPS positivity correlated with mortality and deserves further investigation as a biomarker of poor outcomes.