Thrombotic events in children and adolescent patients with SARS-CoV-2 infection: a systematic review with meta-analysis on incidence and management

Objectives: The present paper aimed to study the available literature on the hypercoagulability state of pediatric patients affected by COVID-19, and the current management of thrombosis in these patients, considering that no guidelines have been published since now in this age group. Methods: N 244 titles were screened using the selected MESH words, 180 abstracts and 120 full texts were read, 12 articles were included, and four were analyzed by meta-analysis. Results: Over 1128 COVID-19 positive patients, nearly half of them developed inflammatory sequelae, and 7.35% (40 patients over 544 who developed MIS-C) had thrombotic events. Less than 50% of patients with inflammatory disease were under anticoagulant prophylactic treatment, and doses of anticoagulant protocols vary from different centers. Thrombotic events prevented after the start of unfractionated heparin (UFH) therapy, even if 1.06% (4 patients) died. Only two patients presented complications after anticoagulant treatment, with non-fatal bleeding after UFH treatment. No other complications were reported. No difference in the incidence of thrombotic events between patients under prophylactic low molecular weight heparin (LMWH) and those without was found in meta-analysis (p = 0.32). Conclusions: Little is known on the incidence and management of hyper coagulopathy in pediatric COVID-19 infection. Further studies have to clarify this topic.