Direct oral anticoagulant therapy in adolescent venous thromboembolism: A systematic review

Adolescent venous thromboembolism (VTE) has unique challenges in management, complications, and compliance to anticoagulants. Direct oral anticoagulants (DOACs) have been approved for pediatric VTE management, with an increasing use especially in adolescents. Primary objective is to evaluate the safety and efficacy of DOAC therapy in adolescent VTE. Secondary objectives include adverse events, bleeding events, and overall mortality. A SR protocol was registered in PROSPERO 2022 (CRD42022363928). Databases were searched from inception to September 22, 2022. Studies with children aged 10-18 years, VTE diagnosis, DOAC therapy, randomized control trials (RCTs), cohort, and relevant study types were included. Studies including prophylaxis, non-DOAC therapy, arterial thrombosis, age outliers, non-relevant study types were excluded. Findings are reported in accordance to PRISMA 2020. Nine reports from five studies, published between 2016 and 2022, were included. Rivaroxaban was the most common DOAC. VTE recurrence was 0.02% in the rivaroxaban phase III trial and one patient in the dabigatran phase IIb/III trial. Complete/partial thrombus resolution (CR/PR) was 76.6% in the rivaroxaban phase III trial, and 83.9% in the dabigatran phase IIb/III trial. CR/PR was found to be 68.4% in Dhaliwal et al. study and 83.3% in Hassan et al. study. Major bleeding occurred in one patient. Headache and gastrointestinal symptoms were commonly seen. All-cause mortality occurred in a patient due to cancer progression. DOAC therapy in adolescent VTE had CR/PR in two-thirds of the patients, with low incidence of VTE recurrence and major bleeding. As there are only two randomized controlled trial (RCTs), future adolescents' studies are required to validate our results.