Thromboprophylaxis in Adults With Atrio-Pulmonary Fontan

Background: Although aspirin has been compared to warfarin for thromboembolic prophylaxis in the general Fontan population, little is known about the optimal preventative strategy for the atriopulmonary right atrium-pulmonary artery [RA-PA]) Fontan particularly. Methods: A retrospective cohort study was performed including adult patients identified in the Ahmanson/ UCLA Adult Congenital Heart Disease Center database with a history of RA-PA Fontan and use of either aspirin or warfarin as most recent primary prophylaxis against thromboembolism. Primary outcome was incident thromboembolism, defined as spaceoccupying lesion on imaging consistent with thrombus within the Fontan or pulmonary arterial circuit. Secondary outcomes were death, transplantation, Fontan conversion, and bleeding requiring either transfusion or invasive intervention. Follow-up was terminated upon achievement of a primary outcome or achievement of a secondary outcome other than bleeding. Kaplan-Meier analysis of freedom from thrombosis was performed. Results: Twenty-six patients met inclusion criteria. Thirteen (50%) received aspirin as most recent primary prophylaxis and 13 (50%) received warfarin. Tricuspid atresia was the most common underlying diagnosis (42%), followed by double-inlet left ventricle (38%). Median age at Fontan operation was 8.2 years; median age at prophylaxis initiation was 25.9 years. After six years, the aspirin group had 50%+/- 35% freedom from thrombosis and the warfarin group 92% +/- 8% (P 1/4 .15). Incidences of secondary outcomes were not significantly different between the groups. Conclusion: In this cohort of long-term Fontan survivors with RA-PA Fontan, the risk of thromboembolic complications is high, especially in those taking aspirin rather than warfarin. Larger studies are needed to confirm these findings.