Incomplete endothelialization and late dislocation after implantation of an Amplatzer septal occluder device.

A 64-year-old woman with a history of a large-sized secundum atrial septal defect (ASD) underwent successful percutaneous closure with a 34-mm Amplatzer septal occluder (ASO) without apparent complications on April 25, 2002. Transthoracic echocardiography immediately following the closing procedure revealed that her ASO was well wedged, with no residual shunt or murmurs (Figure 1). At the third year of follow-up, a small volume of split flow was detected by transthoracic echocardiography. No intervention was attempted at that time because the shunt was not clinically significant and the patient had no uncomfortable symptoms. However, at the last follow-up visit in 2009, the patient had a chest distress and palpitation after daily activity; transthoracic echocardiography showed that the ASO was dislodged into the left atrium and that only a part of the ASO remained at the defect border (Figure 2). A decision was made to surgically remove the ASO (Figure 3). During surgery, we found that the surface of the ASO was only slightly endothelialized on the right side of the disc with approximately 1 cm of the device still adherent to the inferior border of the atrial septum (Figure 4A). There was minimal endothelialization on the left side (Figure 4B). Pathological examination of the explanted ASO showed fibrous connective tissue without thrombi or neoplastic formation on either surface. ASO has become one of the most frequently used systems for transcatheter repair of ASDs. It has been thought that the percutaneous closure of type II ASD with ASO is safe and effective during long-term follow-up.1 Device thrombus for-