OC 08.2 - Thrombotic and Bleeding Complications in Paediatric Inflammatory Multisystem Syndrome Temporarily Associated with COVID-19 (PIMS-TS) in Children: a Systematic Review

Background: Paediatric Inflammatory Multisystem Syndrome Temporarily Associated with COVID-19 in Children (PIMS-TS) is a newly defined inflammatory disease following COVID-19 infection. Limited reports exist investigating thrombosis/bleeding in PIMS-TS.

Aims: To describe the thrombotic and bleeding complications in this population.

Methods: A systematic literature review was conducted searching MEDLINE®, EMBASE and Cochrane Libraries from inception until May 29, 2021. Primary outcomes were prevalence of thrombotic and bleeding complications; secondary outcomes evaluated the anticoagulation regimens used.

Results: One hundred and thirty-two studies met eligibility criteria (124 retrospective, 8 prospective; figure 1) describing 3240 patients (male 58%; mean age 8.3 yrs ± 2.2; table 1). PIMS-TS subtypes (table 1) included shock (47%), fever and inflammation (21%) and Kawasaki disease (4%). Two-thirds of patients (65%; 2118/3240) were critically ill, 40% (1295/3240) required inotropic use, and 2% (58/3240) required ECMO support. Half of patients received anticoagulation (51%; 1638/3240; therapeutic [120]; prophylactic [408]; risk-stratified approach [14]; not specified [1096]) and/or antiplatelet therapy (51%; 1659/3240). Thrombotic events (TE) were reported in about 3% (62/2057) of patients, with DVT/PE (50%; 31/62) being the most common followed by ischemic strokes (IS, 21%; 13/62), and cardiac thrombosis (11%; 7/62). Clinically, TE patients required more mechanical ventilation (MV, 65% vs 20%*) and ECMO support (35% vs 1%*), presenting a higher mortality rate (11% vs 2%*). Bleeding was reported in 2.6% (16/618), of which 60% (10/16) were major bleeding events (MBE). Patients with MBE were more likely to be on ECMO (50% vs 2%*) and MV (70% vs 17%*), and four patients died (40%, 4/10; 2 had concurrent TE).

Conclusion(s): Patients with PIMS-TS are at risk of thrombosis despite widespread anticoagulation use, particularly in critically ill patients (i.e., requiring MV and/or ECMO). MBE are also prevalent in this same risk group and associated with mortality. A risk-stratified anticoagulation approach requires further investigation.

* p value < 0.01