Left Atrial Thrombus on Atrial Septal Defect Closure Device as a Source of Cerebral Emboli 3 Years After Implantation
A 55-year-old man presented with sudden occurrence of recurrent transitoric ischemic attacks with dysphasia and paresis of the left side in May 2004. Other than these symptoms, he presented in good physical condition, with no cyanosis or edema, and his ECG showed regular sinus rhythm at normal rate. Chest x-ray and laboratory studies were unremarkable. He was not taking medication.
His medical history consisted of a patent foramen ovale (PFO) that had been closed 3 years earlier with the Cardio-Seal/Starflex Occluder (33 mm). The PFO was diagnosed because he had presented at the hospital with headache and vertigo. The CT scan of the head showed a small anterior inferior cerebellar infarction with no evidence of tumor or bleeding. Subsequent echocardiography revealed a PFO, and the patient was referred for implantation of the atrial septal defect (ASD) closure device. The immediate postprocedural medication of our center for this device included antiplatelet therapy with aspirin 300 mg daily for 6 months. At 2-year routine follow-up, the patient was doing well, with excellent physical exercise capacity and no neurological symptoms. Echocardiography revealed correct positioning of the closure device and no signs of residual atrial shunt or atrial thrombus formation.
One year later, the patient’s transesophageal echocardiography was normal for ventricular and valvular function but revealed a 1.5-cm left atrial mass originating from the CardioSeal/Starflex Occluder (Figure, A). The 130° orientation showed the correct positioning of the closure device, smooth surface of the device in the left atrium (arrow) as well as no evidence for leg fracture (Figure, A). There was no evidence for residual atrial shunting. The patient was started on coumadin (international normalized ratio 2.5 to 3) and scheduled for surgery.
During cardiopulmonary bypass surgery, the left atrium was opened and a soft thrombus was identified on the tissue covering the device (Figure, B and C). The closure device and some thickened fibrous tissue covering it from either side were removed and sent for pathology, which revealed soft thrombus formation. The thrombus was located on fibrous tissue in the center of the explanted device (Figure, D). The resulting ASD was closed with a GORE-TEX patch (2×3 cm). The patient was weaned off bypass. His postoperative course was uneventful. He was discharged 5 days after surgery on oral aspirin (100 mg, po qd).
The unusual finding in the present report is the late occurrence (3 years after implantation) of left atrial thrombus formation on a correctly positioned closure device. Other reports document that most frequent neurological events occur within the first 12 months postimplantation.1,2 The incidence of thrombus formation ranges from 2.5% to 27%.3 Risk factors for late thrombus generation are the type of device used, atrial fibrillation, incomplete neoendothelialization of the surface of the device, insufficient antithrombotic therapy, and unknown hypercoagulation disorders including aspirin resistance.3
The late occurrence of thrombus formation and neurological symptoms after transcatheter closure of PFO/ASD sug-gests the need for long-term antiplatelet/anticoagulant therapy to avoid thromboembolic events.
↵*The first 2 authors contributed equally to this work.