Percutaneous closure of an atrial septal defect (ASD) has emerged as an alternative to surgery. A 54-year-old woman with a history of percutaneous ASD closure with a 30-mm Cardia Ultrasept septal occluder (Cardia Inc., Eagan, MN, USA) comprising 2 discs made of Nitinol wire mesh covered with polyvinyl alcohol (PVA) membrane, was admitted to the hospital with unstable angina pectoris. In a routine examination, transthoracic echocardiography revealed a left-to-right shunt through the device. Transesophageal echocardiography (TEE) also demonstrated significant left-to-right shunt through the central portion of the prosthesis. Coronary angiography was performed, which disclosed severe stenosis in the right and left anterior descending coronary arteries. Three-dimensional TEE showed multiple perforations of the PVA membrane with intact nitinol frame. Surgical removal of failing device and closure of the ASD with a pericardial patch was performed together with coronary artery bypass graft surgery. On perioperative view, the device appeared to have been correctly implanted, and the device frame was completely intact; however, the PVA membrane of both the right and left discs had almost completely disappeared and there was incomplete endothelialization around the frame. Surgeons must be aware of this rarely seen complication and they should re-examine all patients implanted with Cardia devices in regular follow-up examinations for a long period of time.