Treatment of a ventricular thrombus with rivaroxaban in a patient with hypoplastic left heart syndrome

Hypoplastic left heart syndrome (HLHS) is a severe form of congenital heart disease characterized by poor development of left-sided cardiac structures. The current standard of care aims to create a stable circulation that relies on a single ventricle (SV) by utilizing a series of staged palliative surgical operations, typically leading to a Fontan procedure. These patients are at higher risk of both systemic and intraventricular thromboembolism secondary to abnormal circulation and its sequelae, such as protein-losing enteropathy (PLE). The direct oral anticoagulant (DOACs) drug class acts by direct inhibition of factor Xa, and these medications are gaining popularity for the prevention and treatment of thromboses in the SV population due to their convenient oral route and lack of need for frequent therapeutic level monitoring. While the use of DOACs has been well explored in adult patients, there remains a paucity of literature reporting on DOAC use in the treatment of intraventricular thrombus in the pediatric SV population. We present the first reported case of rivaroxaban use to treat an intracardiac thrombus and describe the clinical course and outcome in a pediatric patient with Fontan circulation.