Neoaortic Thrombus After Norwood Procedure: Complication of Extracorporeal Life Support?

Hypoplastic left heart syndrome is the most common diagnosis among infants requiring cardiac extracorporeal life support (ECLS) in the neonatal period, with more than half of patients experiencing an ECLS-related complication. We present a case of nearly obstructing neoaortic thrombus during ECLS occurring in the early postoperative period after modified Norwood palliation of hypoplastic left heart syndrome. Stasis within the neoaortic root due to the increased ventricular afterload associated with venoarterial ECLS may have potentiated this complication. Echocardiographic monitoring and early cardiac catheterization while on ECLS enabled prompt diagnosis and timely surgical correction.