Abstract
RATIONALE: Deficiency in antithrombin (AT) can significantly increase the risk of venous thromboembolism (VTE). However, there is insufficient data on the efficacy and safety of anticoagulants in patients with AT deficiency, especially in children. In addition, Asian populations typically require a lower dose of rivaroxaban, and this may be even more pronounced in Asian children. This case aims to explore the potential efficacy and safety of a higher dose of rivaroxaban in an Asian child with AT deficiency and VTE. PATIENT CONCERNS: A 15-year-old boy was referred to our center with severe deep vein thrombosis progression. The primary concern was the effective management of the thromboembolic events while minimizing the risk of bleeding, given the patient's young age and AT deficiency. DIAGNOSES: The patient was diagnosed with pulmonary embolism and deep vein thrombosis with AT deficiency. INTERVENTIONS: The patient was treated with a higher dose of rivaroxaban, which was 15 mg twice a day for 3 weeks, followed by 20 mg per day for 6 months, which was a relatively high dose for an Asian child. OUTCOMES: During the follow-up period, the patient did not experience any VTE events or bleeding events. LESSONS: This case provides additional data on the efficacy and safety of direct oral factor Xa inhibitors in patients with VTE and AT deficiency. It suggests that for Asian children with AT deficiency, considering a higher dose of rivaroxaban could be beneficial, especially when the children's height, weight, and age are close to adults.