Use and Outcome of Anticoagulant Therapy in Children with Congenital Heart Disease: Insights from a Nationwide Population Based Study

All articles of this category (opens in new window) Background: The aim of this study was to provide population-based outcome data on antithrombotic regimens after operation or intervention in pediatric congenital heart defect (CHD) patients with a special focus on additionally focusing on the subgroup of Fontan patients. Methods: Using data from one of Germany’s largest Health insurers, CHD patients who underwent an intervention or surgery between 2005 and 2023, and before the age of 18, were assessed for prescription of antithrombotic therapy. Patients were followed from the time of each procedure until their 18th birthday or a subsequent procedure. Primary endpoints were death, thrombosis, and bleeding. Outcomes were analyzed in relation to time-varying anticoagulation therapy and adjusted for individual patient risk profiles. Fontan-type procedures were analyzed separately. Results: A total of 6,506 CHD patients (47% female) with 9,484 procedures were included. Median age at intervention was 1 year (interquartile range [IQR]: 0–6) with a median follow-up of 3.1 years (IQR: 0.7–7.7) after each procedure. Among the 30% of cases in which antithrombotic therapy was administered, 79% received antiplatelet therapy (APT), 15% vitamin K antagonists (VKA), 20% heparin, and 2% NOAC. Medication changes occurred in 4% of cases. All-cause mortality was not different in the groups. A total of 236/86 initial minor and major thrombotic events and 771/106 initial bleeding events were found. After adjustment for patient characteristics and risk factors, VKA was not associated with a lower risk of thrombosis or death of any cause compared with APT (HR: 1.56, 95% CI: 0.97–2.53, p = 0.07) or with an increased risk of bleeding or death of any cause (HR: 1.19, 95% CI: 0.80–1.79, p = 0.39) on multivariable analysis. Similar results were observed in a subgroup analysis of 326 Fontan-type procedures (median follow-up: 6.4 years, IQR: 2.4–11.6) where VKAs were not associated with risk of thrombosis/death (HR: 3.08, 95% CI: 0.83–10.71, p = 0.08) or bleeding/death (HR: 0.79, 95% CI: 0.37–1.63, p = 0.5) compared with APT. Conclusion: Major thrombosis and bleeding are rare in pediatric CHD patients. In this real-world nationwide analysis, CHD patients on APT do not appear to have a statistically noticeable higher risk for thrombotic events compared with those receiving VKA. A finding is also present in the Fontan subgroup. These findings do not support the routine use of VKA over APT, particularly in Fontan patients. Publication History Article published online: 17 February 2026 © 2026. Thieme. All rights reserved. Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany