Thrombus formation on an atrial septal defect closure device

Atrial septal defects (ASDs) are the most prevalent form of congenital heart disease presenting after childhood. Percutaneous closure has become a safe and effective strategy for managing adults with secundum-type ASDs. Reports on complications are rare. The present report discusses a case of rapid formation of a large thrombus on an ASD transcatheter closure device. The case highlights the importance of transesophageal echocardiography during the procedure and supports the role of periprocedural anticoagulation in transcatheter ASD closures.