Comprehensive coagulation function evaluation in a boy with antithrombin deficiency during rivaroxaban administration

Abstract

Antithrombin (AT) deficiency is an inherited form of thrombophilia. Little is known about the efficacy of direct oral anticoagulants (DOACs) in children with AT deficiency. Information on the primary prevention of thromboembolism using DOACs are limited. We present patients with AT deficiency and their family members across five generations. A 7-year-old boy, weighing 19.4 kg, had 51% AT activity with a splice variant of SERPINC1. During the trial with 15 mg/day rivaroxaban, the shortened coagulation time was compared to that of healthy individuals. The maximum coagulation acceleration after rivaroxaban administration was lower than that in healthy individuals. Thrombin generation is elevated during COVID-19 and that under administration was lower than that of healthy individuals, providing reference information for the dosage of rivaroxaban. Accumulation of pediatric cases is required to establish an optimal dosage of DOACs for the prophylaxis and treatment of thrombophilia.