Late Presentation of CardioSEAL PFO Closure Device Fracture and Thrombus Formation Three Years after Device Implantation

Author Affiliations: From the *Division of Cardiology, LAC and USC Medical Center, and the §ICCU, Department of Internal Medicine, Keck School of Medicine, Los Angeles, California. The authors report no conflicts of interest regarding the content herein. Manuscript submitted November 8, 2007, provisional acceptance given May 20, 2008, and accepted May 27, 2008. Address for correspondence: Vidya Narayan, MD, 1200 N State St, Room 7440, Division of Cardiology Office, Los Angeles, CA 90033. E-mail: vnarayan@usc.edu

_______________________________________________ ABSTRACT: Transcatheter closure of patent foramen ovale (PFO) is a promising alternative to surgical closure or anticoagulation therapy in patients with a history of cryptogenic stroke. Although a number of transcatheter closure devices have been developed and used outside of the United States, the two commonly used devices in the United States are the StarFLEX CardioSEAL® and the Amplatzer® Occluder. Several complications, both early and late, associated with the devices have been reported in 6–11% of patients. The rates of complication vary with the different devices. Complications include device related thrombi, embolization, device malposition, fracture, air embolism, arrhythmias, pericardial effusion, need for surgical intervention and death. As reported in the literature, the incidence of long-term complications beyond 1 year is rare. We report a case of a very late presentation of CardioSEAL device arm fracture associated with left atrial thrombus 3 years after device implantation.

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J INVASIVE CARDIOL 2008;20:E247–E249 Transcatheter closure of patent foramen ovale (PFO) is a promising alternative to surgical closure or anticoagulation therapy in patients with a history of cryptogenic stroke. Although a number of transcatheter closure devices have been developed and used outside the United States, the two commonly used devices in the United States are the StarFLEX CardioSEAL® (NMT Medical, Inc., Boston, Massachusetts) and the Amplatzer® PFO Occluder (AGA Medical Corp., Plymouth, Minnesota). The overall incidence of complications associated with these devices has been reported to be between 6–11%.1 These include device-related thrombi, embolization, device malposition, fracture, air embolism, arrhythmias, pericardial effusion, surgical intervention and death.2 The incidence of late complications beyond 1 year is rare. We report a very late presentation of a CardioSEAL device arm fracture associated with left atrial thrombus formation presenting 3 years after device implantation. Case Report. The patient is a 37-year-old female who underwent PFO closure with a CardioSEAL device in May 2004 for a right middle cerebral hemispheric cerebrovascular accident (CVA). One month prior to device implantation, she presented with left-sided weakness and expressive aphasia. A magnetic resonance imaging (MRI) scan of the brain revealed a subacute right middle cerebral infarct. Transesophageal echocardiography (TEE) showed a 2 mm PFO detected with an agitated saline bubble study. Subsequently, the patient underwent a workup for underlying hypercoagulable state, which was negative. She underwent successful percutaneous closure of the PFO with a 33 mm CardioSEAL device under intracardiac echocardiographic (ICE) guidance. She was placed on antiplatelet therapy with aspirin 325 mg and clopidogrel 75 mg for 6 months. A follow-up evaluation in January 2005 revealed complete resolution of her neurological deficits. A transthoracic echocardiogram (TTE) with an agitated saline bubble study showed a well-seated device with no evidence of residual shunting. The patient remained asymptomatic for 3 years after device implantation when she presented to her cardiologist with a transient ischemic attack (TIA) in May 2007. She was evaluated with a TTE, which showed a left atrial thrombus attached to the PFO closure device. She was treated with warfarin for a period of 3 months, with no change in the size of the thrombus. During this period, she suffered a significant pulmonary hemorrhage from supratherapeutic international normalized ratio (INR) requiring prolonged hospitalization. Anticoagulation was discontinued and she was referred to our institution for surgical removal of the device and the thrombus. On presentation, the patient’s physical examination, chest radiograph, electrocardiogram, laboratory studies were unremarkable. She underwent repeat TTE and TEE, which confirmed a 1.7 x 1.8 cm pedunculated mobile mass attached to the PFO closure device, suggestive of a thrombus (Figures 1 and 2). The PFO device appeared to be intact and well seated. She was taken to surgery for removal of the thrombus and the device. Intraoperatively, the left superior arm of the device was found to be exposed and protruding into the left atrium. A 2 x 2 cm well-circumscribed left atrial mass was attached to the interatrial septum at the site of the exposed arm (Figure 3). The left atrial mass was excised at the stalk. Pathology revealed a well-organized thrombus with an estimated age between 6–8 weeks (Figure 4). The device was removed and appeared well endothelialized except at the site where a part of the left superior arm of the device appeared to be missing (Figure 5). The interatrial septum was then closed primarily without a patch. The patient’s postoperative course was uneventful, and she was discharged home 4 days after surgery. The unusual finding in our case is the very late occurrence of the device fracture and thromboembolic complication, which to our knowledge, has not been previously reported in the literature. Discussion. Catheter closure of PFOs using the Clamshell device was first reported by Bridges et al in 36 patients with presumed paradoxical emboli.3 The incidence of arm fractures with the clamshell device at 1–6 months’ follow up was up to 84%.3 The CardioSEAL septal occluder was developed as a modification of the clamshell occluder in 1988 in order to reduce the incidence of metal arm fractures.3,4 The CardioSEAL is a self-expanding comprised of two square umbrellas made of a dacron patch and are supported by four nitinol spring arms radiating from the center. The two umbrellas are attached to each other in the center. The sizes available are 17, 23, 28, 33 and 40 mm. The measurement denotes the length of the diagonal of the umbrella.5 The incidence of wire fractures in the CardioSEAL device during the first 6 months after implantation, as reported in the literature, varies from 5–20%.6 Most of these fractures have been detected in 33 mm and 40 mm devices by fluoroscopic examination and have not been associated with serious clinical consequences. To our knowledge, this case is the first of its kind reported in the literature to show a very late occurrence of device fracture associated with thromboembolic complications 3 years after implantation. The device fracture was not obvious on preoperative TTE or TEE, but was clearly identified intraoperatively. The device used in this case was a 33 mm CardioSEAL, which on intraprocedural echocardiography, was found to have a mild splaying of the superior left atrial arm of the device with incomplete apposition against the interatrial septum. The long-term stress on the splayed left superior arm of the device might have contributed to the fracture. The exact timing of the device fracture cannot be ascertained, however, the age of the thrombus and the timing of the associated clinical event point toward a delayed occurrence of the device fracture. In a study by Seivert et al, wire fractures in PFO closure devices associated with thrombus formation occurred in 15% of the patients.7 It was proposed that the nonendothelialized exposed metallic arm of the device serves as a nidus for thrombus formation over time. Atrial thrombus formation after percutaneous interatrial defect closure has been reported to vary from 3–27%.8 The incidence varies for different devices and appears to be significantly more common with the CardioSEAL (7.1%), StarFLEX (5.7%) and Prostar (6.6%) (Abbott Laboratories, Abbott Park, Illinois) devices as compared to the Amplatzer Occluder (0.3%).7 Anzai et al8 also reported TEE evidence of thrombus formation in 22% of the CardioSEAL devices and 0% of the Amplatzer devices. The uncoated metallic framework and dacron fabric in the CardioSEAL devices have been proposed to increase the risk of excessive thrombus formation.7,9 Thrombus formation related to PFO closure devices is clinically silent in most cases, detected only during routine TEE and not apparent on TTE.8 The incidence of thrombus formation is highest during the first 4 weeks after device implantation and is extremely rare after 8–12 months.10–12 Most of these thrombi resolve with continued anticoagulation therapy without clinical consequences. The need for surgical intervention to remove thrombus and the device is extremely uncommon.8 The majority of the recurrent neurological events related to thromboembolic phenomena have been reported to occur within the first year after device implantation.11,12 Our case illustrates the very late occurrence of device fracture and thrombus formation presenting 3 years after device implantation. This suggests a need for longer periods of surveillance post transcatheter PFO and ASD closure to monitor for the late occurrence of fatigue fractures, which may be associated with clinically important thromboembolic events.

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