Introduction
Coronavirus disease 2019 (COVID-19), caused by the novel coronavirus SARS-CoV-2, has had a tremendous impact since the first cases were reported in China in December 2019. Since April 2020, cases have emerged of healthy children presenting with a severe, immune-mediated, multi-organ system illness following SARS-CoV-2 infection, which has since been termed “multisystem inflammatory syndrome in children” (MIS-C).1–5 Patients with MIS-C have evidence of significant abnormalities in the inflammatory cascade and hemostasis, including elevated fibrinogen and D-dimer.6–9Reported rates of thromboembolism in the pediatric MIS-C population range from 3 to 6.5%.6,10,11 Derangements in hemostasis in adults with severe COVID-19 infection are more pronounced and better characterized. In the adult literature, SARS-CoV-2 infection is associated with a prothrombotic state, with viscoelastic testing consistent with early thrombin burst, increased fibrin generation, greater clot strength and reduced fibrinolysis.12–14This has been consistent with evidence that approximately 20-40% of adults with severe acute COVID-19 infection in intensive care units (ICU’s) are affected by thromboembolism despite anticoagulation.15–17
Thromboelastography (TEG) is a point of care, whole blood viscoelastic test that is widely established in adults and used to characterize clot formation and lysis kinetics as well as clot strength.18 Increased in vitro clot strength on TEG is associated with increased risk of thromboembolism in critically ill adult patients.19 TEG has shown promise in pediatric care, including guiding management of product resuscitation and thrombosis risk.20–22 We sought to describe the coagulation and viscoelastic testing profiles of children with MIS-C at our institution, as well as our approach to thromboprophylaxis in these patients.