Transcatheter closure of atrial septal defects

The first transcatheter closure of an atrial septal defect (ASD) was performed by King and Mills in 1976. The Lock Clamshell occluder and the buttoned device are the latest devices to undergo clinical trials. Successful transcatheter closure has been possible with minimal morbidity and mortality. Small residual shunts may remain, however, in up to 20% of patients 1 year after the procedure. The clinical significance and natural history of these small residual atrial communications remains to be determined. This article reviews the history and development of the current ASD closure techniques, with emphasis on the experience with the Lock Clamshell occluder and the buttoned device.