Abstract 3675: Thrombus Formation on ASD and PFO Devices: Frequency and Clinical Importance
Background: Percutaneous transcatheter closure of patent foramen ovale (PFO) and atrial septal defects (ASD) has been shown to be feasible with few risks. One risk with clinical significance may be post-implant thrombus formation on occluder devices. We analyzed its clinical outcome by evaluating its incidence, morphology and clinical relevance using transesophageal echocardiography (TEE) during the procedure and clinical course.
Patients and Methods: Transcatheter closure of PFOs and ASDs has been performed in 1229 PFO and 679 ASD patients with a total of 997 Amplatzer, 396 Helex, 306 StarFLEX 37 ASDOS, 11 CardioSeal and 172 “other devices” implantations. Clinical follow-ups with TEE controls were performed after 1 and 6 months post-implant and if clinically indicated. Antiplatelet therapy or coumadin (ASDOS occluder) were admistered for six months.
Results: In 22 of 1908 patients thrombus formation occurred (PFO 1.2%, ASD 1.0%, p=NS). Two patients developed a thrombus on both sides of the atrial septum, six patients only on the right atrial side and 13 patients only on the left side. In one patient a thrombus was found next to the Eustachean valve. The post-implant follow-up surveillance revealed: thrombus in 14 patients at one month, 4 additional patients at three and 6 additional patients at 6 months. One thrombus on the CardioSeal (1/11 = 9.1%), three on the ASDOS (3/37 = 8.1%), 13 on the StarFLEX (13/306 = 4.2%), three on the Helex (3/396 = 0.8%) and two thrombi on the Amplatzer (2/997 = 0.2%) device were diagnosed. The rate of thrombus formation was significantly higher in StarFLEX, ASDOS and CardioSeal (p < 0.05) than in Amplatzer and Helex occluders. Two strokes and one TIA occurred in three patients. Potential risk factors for thrombotic formations did not affect the incidence of thrombus presence (p=NS). In most patients (19/22) the thrombi could medically be resolved without clinical sequalae and in only 3 patients surgical intervention was required.
Conclusion: The development of thrombi on occluder devices is a rare occurrence. Thrombus formation usually resolves with medical treatment; however it may be the cause of repeat neurological events. Thrombus formation may have a predilection toward certain occluder types.