Late recognition of Gore Helex atrial septal occluder fracture and migration

Abstract

Patent foramen ovale (PFO) closure is indicated in cryptogenic stroke. Percutaneous PFO closure is both feasible and highly efficacious with low incidence of device-related complications. When complications occur, they are usually discovered within 6 weeks of device deployment. We describe the case of a partially embolised and fractured Gore Helex Septal Occluder device recognised nearly 9 years after placement requiring surgical explant.

<Learning objective: Device-related complications with patent foramen ovale closure devices are exceeding rare. Our case highlights the need for continued long-term device monitoring with periodic imaging given the ongoing risk for device-related complications.>

Introduction

Percutaneous patent foramen ovale (PFO) closure recently regained traction after several trials demonstrated superiority over medical therapy in cryptogenic stroke with low complication rate [1]. In a meta-analysis of 1355 patients who underwent percutaneous PFO closure, major complications (death, tamponade and need for surgical intervention) occurred in only 1.5% of patients, and minor complications (device embolisation, fracture, thrombosis, arrhythmias and femoral access complications) occurred in 7.9% of patients [2].

Patent foramen ovale closure device embolisation following successful implantation is a very rare complication with previously reported incidence of 0.7% within three years of implantation [3]. We report a rare case of very late recognition of a 25 mm Gore Helex Septal Occluder (HSO, W.L. Gore & Associates, Flagstaff, AZ) device migration requiring surgical extraction.

Case

A 61 year-old man was seen in consultation regarding residual right-to-left interatrial shunting following PFO closure. The patient experienced a right middle cerebral artery stroke 8 years prior to his current presentation confirmed on brain magnetic resonance imaging. Bilateral lower extremity venous Doppler study showed no evidence of deep vein thrombosis, however, the stroke occurred immediately following an eight hour flight from France to United States leading to high suspicion for occult paradoxical embolic event. Transthoracic echocardiogram (TTE) followed by transesophageal echocardiogram (TEE) revealed a long-tunnel PFO 2 cm in length with bidirectional shunting and a highly mobile septum with 10 mm excursion not meeting criteria for atrial septal aneurysm. No alternate aetiology for the embolic stroke was identified.

One year following the stroke, he underwent percutaneous PFO closure with a 25 mm Gore HSO. No procedural difficulties were noted. Peri-procedural fluoroscopy demonstrated well-positioned left and right atrial discs on opposite sides of the interatrial septum, though, with greater separation between the centre and right eyelets than the centre and left eyelets due to the long PFO tunnel (Fig. 1A). Intra-procedural TEE revealed no residual shunt. Annual follow-up TTE during the first two years suggested left-to-right atrial communication on colour Doppler. Poor echocardiographic windows limited interatrial septum interrogation. Evaluation with TEE was recommended, however, given his lack of symptoms and desire for conservative management, the patient declined further imaging. Following his third annual surveillance TTE, the patient ceased follow-up for several years. Routine surveillance TTE at year eight demonstrated a small interatrial shunt but now with right-to-left flow. Out of concern for potential recurrent stroke in the setting of residual right-to-left shunt, the patient sought a second opinion at our institution to evaluate options for definitive PFO closure.

Fig. 1.

(A) Fluoroscopy at index procedure demonstrating adequate placement of Gore Helex Septal Occluder device and appropriate closure of locking mechanism capturing all 3 eyelets. The long PFO tunnel may be appreciated through the greater separation between the centre and right eyelets (long arrow) compared to the centre and left eyelets (short arrow). (B) Fluoroscopy at the time of attempted percutaneous device retrieval reveals partial device unravelling with fracture (arrow) of Gore Helex Septal Occluder right atrial disc Nitinol wire frame.

Transesophageal echocardiogram revealed that a portion of the right atrial disc had become malpositioned and all the component pieces of the occluder device could not be clearly identified (Fig. 2). Given the patient's desire for percutaneous PFO closure and complicated interatrial tunnel, a structural heart team discussion determined that percutaneous PFO closure with placement of a second occluder could still be attempted.

Fig. 2.

Transesophageal echocardiogram image demonstrates malpositioned Gore Helex Septal Occluder 8 years after placement that now appears to be partially located within the PFO tunnel though all the component pieces cannot be clearly identified.

On the day of the procedure, simultaneous fluoroscopy and intra-procedural TEE revealed that a portion of the Gore HSO right atrial disc was no longer adherent to the septum and now resided within the body of the right atrium protruding into the superior vena cava (Fig. 1B). Additionally, a wire fracture affecting the right atrial disc was noted (Videos 1 & 2). The presence of a wire frame fracture and uncertainty as to how firmly adherent the left atrial disc was to the septum led to a decision not to attempt percutaneous removal. The patient was referred for surgical extraction of the Gore HSO and PFO closure. Surgical access was obtained through the right atrium. The fractured portion of the Gore HSO right atrial disc wire frame was found to be at the inlet of the superior vena cava and was dissected away from the atrial wall (Fig. 3A). The left atrium was accessed through the interatrial septum. The left atrial disc had migrated and fused to the dome of the left atrium well superior to the foramen ovale itself and was resected via sharp dissection (Fig. 3B). Following dissection and removal of the septal occluder device, the interatrial septum was sutured primarily and did not require patch material (Fig. 3C). The explanted device revealed a partially unravelled 25 mm Gore HSO with a right atrial disc wire frame fracture (Fig. 3D). Intraoperative TEE demonstrated closure of the PFO without interatrial shunting and follow-up TTE 1 month following surgery confirmed the absence of residual interatrial shunt.

Fig. 3.

(A) Gore Helex Septal Occluder was removed via sharp dissection from right atrium/superior vena cava (arrow) with LA disc adherent to the atrial tissue within forceps. (B) Dissection of Gore Helex Septal Occluder left atrial disc from roof of left atrium. (C) Repaired atrial septum and closure of PFO following removal of Gore Helex Septal Occluder is shown with the suture line identified by an arrow. (D) Surgically explanted Gore Helex Septal Occluder 8 years post implant. Note tissue in-growth. Nitinol eyelet deformity in part surgically induced during device removal.

Discussion

The 2014 AHA/ASA guidelines recommend a class IIb recommendation for PFO closure following cryptogenic ischaemic stroke in the setting of paradoxical embolism if there is continued risk of recurrent deep vein thrombosis [4]. Currently, two FDA-approved devices are available for PFO closure: Amplatzer PFO Occluder and Gore Cardioform Septal Occluder device.

The Gore REDUCE trial demonstrated the superiority of PFO closure with the Gore HSO and Gore Cardioform devices over medical therapy alone in preventing recurrent cryptogenic ischaemic stroke [3]. Gore HSO is no longer available and has been supplanted in clinical practice by the next generation Gore Cardioform septal occluder device.

Case reports indicate the rarity of PFO closure device explant by surgery [5], [6], [7]. Prior explants of Gore HSO have occurred within the first 2 years after device placement. Indications for device removal included late thrombus formation (1 year), wire frame fracture events resulting in tamponade (20 months) or mitral valve perforation (6 weeks), and device unlocking and unravelling (15 weeks) [5], [6], [7]. To date, there is only one report in the literature of a very late surgical explant of a percutaneous Cardiac atrial septal closure device, a device which is no longer available, more than 10 years after placement for a perforation event resulting in tamponade [8].

Several possible mechanisms may explain the migration of our patient's PFO closure device. The Gore HSO device consists of dual occluder discs composed of expanded polytetryafluoroethylene (ePTFE) material mounted on a Nitinol wire frame with wire loop eyelets at the ends of the discs and one in between the discs. Once fully deployed, the device assumes a double disc configuration stabilised by a locking loop that captures all 3 eyelets. Prior studies indicate that technical difficulties leading to occasional non-capture of the right atrial eyelet that may contribute to device embolisation [7].

The patient's pre-procedural TEE demonstrated a long-tunnel PFO measuring 20 mm and a mobile septum with maximum total excursion of 10 mm. While the Gore HSO was not recommended for closure of PFO associated with aneurysmal interatrial septum or in tunnels longer than 18 mm, published reports of use in these settings indicate procedural success in the majority of such cases [5,7]. These studies have noted a higher degree of immediate post-procedural residual shunting in the presence of atrial septum aneurysm. Over months, this residual shunting appeared to decrease as the device endothelialized. The Gore HSO was designed to be more compliant than other PFO occlusion devices that may lead to delayed endothelialization in the presence of a mobile septum and subsequently increase device embolisation risk.

Given these reports and our own anecdotal experience, we believe that despite our patient's challenging anatomy, a percutaneous approach to PFO closure was justified. We suspect this patient's device migrated in the first year post-procedure. We posit that the patient's long PFO tunnel measuring 20 mm resulted in too wide a separation between the two discs. The force of atrial contraction may have unhinged the locking mechanism from the right atrial disc allowing this disc to migrate. This was not recognised due to poor TTE acoustic windows and the patient's desire solely for non-invasive monitoring studies. We suspect the wire frame fracture also occurred within the first year post-procedure since the explanted device was completely endothelialized and adherent to the atrial wall. The American Society of Echocardiography recommends surveillance TTE should be performed prior to hospital discharge, 1 month, 6 months, 12 months and then every 1–2 years following device placement [9]. When the septal occluder device cannot be adequately assessed by TTE, expert opinion recommends periodic TEE evaluation. Multidetector computed tomography may also be utilised for non-invasive surveillance in select patients.

In our patient, the operative findings of the left atrial disc adherent to the left atrium support the conclusion that attempted percutaneous snare removal would have been either traumatic resulting in septal trauma or not possible. The combination of anatomical characteristics: a highly mobile interatrial septum and a long PFO tunnel length, along with device characteristics: a compliant mid-sized occluder susceptible to both wire frame fracture from compression and device embolisation may have contributed to device migration and residual shunting.

Conclusion

Patent foramen ovale closure device embolisation and the need for very late surgical explant is an exceedingly rare event. When a device requires surgical removal, the procedure usually occurs in the early period after placement due to device migration prior to endothelialization. Our case highlights the need for long-term device monitoring with imaging given the continued risk for device-related complications.

Declaration of Competing Interest

The authors declare there are no conflicts of interest.

Appendix. Supplementary materials

Video 1.

Transesophageal echocardiogram video of Gore Helex Septal Occluder 8 years post implant demonstrates right atrial disc migration through the right atrium spanning into the superior vena cava.

Video 2: .

Fluoroscopic view at the time of attempted percutaneous device retrieval reveals fracture of Gore Helex Septal Occluder right atrial disc Nitinol wire frame.