HELEX Septal Occluder Research Articles

Partial prolapse of a HELEX device associated with early frame fracture and mitral valve perforation

One or more breaks in the wire frame of the HELEX Septal Occluder (W.L. Gore and Associates, Flaggstaff, Arizona) were identified in 5% of patients in the multicenter pivotal trial leading to FDA approval. Fractures of the perimeter frame have not previously been associated with any apparent deleterious clinical effects. We report a case in which the broken ends of wire at a frame fracture were located in a position that resulted in perforation of the anterior mitral valve leaflet. There was significant mitral regurgitation and the device was removed surgically. The possible etiologies and prevention of wire frame fractures are also discussed.

Fracture of the GORE HELEX septal occluder: Associated factors and clinical outcomes

This study examines factors associated with, and clinical effects of, wire frame fractures (WFF) of the GORE HELEX Septal Occluder (HELEX). Investigator-reported data from every HELEX implanted in the United States between 4/2000 and 4/2005 were reviewed. Clinical and procedural data from patients who experienced WFF were compared with data from patients who did not. The echocardiographic and fluoroscopic images for HELEX with WFF were reviewed for predictors of WFF and alterations in HELEX function. With 90% of subjects followed for >12 months, 19/298 (6.4%) HELEX implanted were found to have WFF. Thirty WFFs were observed, with multiple WFFs occurring in 8/19 HELEX. Univariate predictors of WFF were large device size (P = 0.0003) and balloon defect size (P = 0.001); however, large device size (P = 0.0003) was the only significant predictor of WFF by multivariate analysis. WFF of the 30-mm and 35-mm HELEX accounted for 84% (16/19) of all WFFs. Review of HELEX images with WFF revealed all WFF occurred along the circumferential wire, except one (straight portion of locking loop). Seventeen of 29 (59%) circumferential WFFs were on the right disk. Residual defect status remained clinically insignificant (6/19) or became completely occluded (13/19) during follow-up. There were no clinical sequelae due to WFF; however, secondary to right atrial disk mobility, the HELEX with locking loop WFF was percutaneously removed 6 weeks after implantation. WFF occurred in 6.4% of HELEX and were most common in large devices. With the exception of one device removed for theoretical risks, no clinical sequelae were related to WFF. WFF did not alter the function of the HELEX.

Fracture of a GORE HELEX Septal Occluder following PFO closure in a diver

Decompression illness (DCI) is more common in divers with a patent foramen ovale (PFO), and transcatheter PFO closure is being increasingly performed in patients with an episode of DCI who want to continue diving. A range of closure devices are available and the choice in an individual case depends on operator preference and PFO anatomy. The GORE HELEX Septal Occluder, introduced in 1999 primarily for secundum atrial defect closure, is a compliant non self-centering device composed of a wire helical framework on which a microporous membrane is mounted. The device is fixed in place by a unique interlocking mechanism that passes through the center of the device from the left to the right atrial disc, thereby securing it onto the interatrial septum. Here, we present a case of a locking loop fracture and review the literature concerning this unusual complication.

Midterm Follow‐Up of Percutaneous Closure of Secundum Atrial Septal Defect with Helex Septal Occluder

The Helex Septal Occluder (HSO) is a relatively new device used in the percutaneous closure of atrial septal defects (ASDs). The immediate and short-term results of its deployment have been reported, but the medium-term results have not been described. The objective was to describe the midterm efficacy and safety of percutaneous closure of ASD with the HSO. The HSO was used in 33 children to close secundum ASDs between July 1999 and November 2000. Detailed data were collected at implantation and 31 children have been followed clinically and investigated with electrocardiogram (ECG) (n = 30), echocardiogram, and fluoroscopy (n = 30) at a mean of 63 (range 55-74) months after implantation. The ages and body weights at implantation ranged from 13 to 220 months and 7.6 to 57.6 kg. The ASD diameter ranged from 7 to 17 mm. All sizes of HSO were deployed. The range of device to defect ratio was 1.4 to 3.3. Of the 21 residual shunts noted early after implantation, only four persisted, all small, at latest follow-up. There were no new shunts. There were no new ECG abnormalities. There was a pronounced change in the configuration of one HSO without sequelae. In two patients in whom the locking loop missed the right atrial eyelet at deployment, there were no sequelae or residual shunts. There were no cases of frame fracture or explantation. There has been no death or long-term morbidity. At midterm follow-up the HSO is durable and effective, with a low incidence of adverse sequelae even in the small subgroup with imperfect configuration.

Helex Septal Occluder: Feasibility Study of Closure of Atrial Septal Defect

A variety of transcatheter atrial septal defect (ASD) occluders are currently in use, the most commonly used device is the Amplatzer Septal Occluder (ASO) yet there is no perfect device. The Helex Septal Occluder is a new device (by W.L. Gore & Associates, Inc.) designed to improve the results of transcatheter ASD closure. We report our first experience in closing secundum ASDs with this new device after its recent modifications. Thirteen patients were selected for Helex device closure with median age of 8 years (2.5-44 years) and median weight 30 Kg (12-96 Kg). Inclusion criteria were: small to moderate Secundum ASDs with sufficient rims by transthoracic echo (TTE) and confirmed by transoesophageal echo (TEE). Two cardiologists carried out the decision of device size. One of the five available Helex ASD device sizes was used (15-35 mm). Follow up TTE was performed the next day, one month, six months and one year later. Twelve patients had successful Helex septal occluder implantation. One patient was switched to Cribriform ASD device during the procedure because of failure of the locking mechanism. Two patients had trivial residual left to right shunt which disappeared at one month follow up in one patient. No embolic event, AV block or mortality was observed. This feasibility study of the novel Helex septal occluder after its recent modification showed that it can successfully and safely close well selected secundum ASDs. There are several advantages over the currently available devices.

Results of the U.S. Multicenter Pivotal Study of the HELEX Septal Occluder for Percutaneous Closure of Secundum Atrial Septal Defects

This study sought to compare the safety and efficacy of the HELEX septal occluder (HSO) with surgical repair of atrial septal defect (ASD). The HSO is a low-profile, double-disk occluder device for percutaneous closure of secundum ASD. Patients were enrolled (HSO arm prospectively, surgery arm prospectively/retrospectively) from 14 U.S. sites and followed up for 12 months postprocedure. Investigator-reported outcomes were evaluated, including closure success (no or clinically insignificant residual shunt) and the incidence of adverse events. The first 3 HSO patients at each site were considered training cases and were excluded from analysis. Between March 2001 and April 2003, 119 nontraining cases received an HSO and 128 had surgical repair. The groups were similar with statistical but clinically unimportant differences in median age, weight, and preprocedural echocardiographic defect size. Anesthesia time and hospital stay were significantly shorter in the HSO group. Closure success, defined as complete closure or a clinically insignificant residual shunt, was similar in both groups. Major and minor adverse events rates were not statistically different. The most common major adverse events for the HSO group was device embolization requiring catheter retreival (1.7%), and in the surgery group was postpericardiotomy syndrome (6.3%), including one death because of tamponade. The primary end point, clinical success, a composite of closure success and no major adverse events at 12 months, satisfied the noninferiority hypothesis comparing device closure with surgery. Closure of ASD with the HELEX septal occluder is safe and effective when compared with surgical repair, with reduced anesthesia time and hospital stay. (U.S. Multicenter Pivotal Study of the HELEX Septal Occluder for Percutaneous Closure of Secundum Atrial Septal Defects; this study was approved by the Food and Drug Administration before the National Institutes of Health website was active, so there is not a URL or registration number.).

Percutaneous closure of an iatrogenic atrial septal defect

We report the successful percutaneous closure of an iatrogenic atrial septal defect in a 71-year-old woman. The patient had undergone mitral valve replacement and coronary artery bypass grafting, followed by redo surgery to repair a para-valvular mitral leak. Post-operatively she remained significantly limited by dyspnoea. Repeat transoesophageal echocardiography documented a large iatrogenic atrial septal defect. The patient underwent percutaneous, trans-femoral closure of the defect using the Helex septal occluder (W.L. Gore, Newark, Delaware, USA) with dramatic clinical improvement.

The Design and Deployment of the HELEX Septal Occluder

The GORE HELEX Septal Occluder (W.L. Gore and Associates, Flagstaff, Ariz, USA) is the latest device to pursue U.S. Food and Drug Administration (FDA) approval for the closure of secundum atrial septal defects. The device is soft and compliant with comparatively little metal framework. It can be deployed and retrieved without damaging the device, and has a safety cord attached that allows retrieval even after it has been disconnected from the delivery mandrel. With FDA approval, operators will now have a choice of devices for the closure of atrial septal defects. Significant differences exist between the HELEX device and existing atrial septal occluders. This article explains the HELEX device design, provides recommendations for preprocedural screening and preparation, and discusses the deployment technique in detail. The device may be particularly advantageous for patients with small- to moderate-sized atrial septal defects.

Analysis of factors related to successful transcatheter closure of secundum atrial septal defects using the HELEX septal occluder

The HELEX septal occluder is a new transcatheter atrial septal defect occlusion device. This study analyzes the data collected from the first US clinical trials with this device to determine the most significant factors in successful use of the device. Tables of subsets of data were constructed in categories of possibly significant patient and device variables compared with important outcomes. Chi2 analysis was used to determine which variables had significant impact on outcomes. The device was successfully implanted in 87% of patients (298/342). A major adverse event occurred in 5.8% (mostly device removal for various reasons). A significant residual leak persisted at 1 year in 2.6%. A fracture of the wire frame occurred in 8%--all were asymptomatic and only 1 required treatment. Overall composite success (no significant leak and no major adverse event) was seen in 91.5%. Patient age, body surface area, and device size had no significant influence on outcomes, except that wire frame fractures were more likely with the 35-mm device. Defect stretch diameter had the largest influence on outcomes, and implantation was possible in only 67% if the stretched diameter of the defect was >20 mm. Device-defect ratio also had a significant effect on delivery success and composite success. The HELEX septal occluder is best suited for small to moderate atrial septal defects with a stretch diameter <20 mm. Although composite success was achieved in 80% of patients when a device-defect ratio <1.6 was necessitated or elected, use of a device that provided a ratio >2 resulted in 95% composite success, and is recommended when possible.

HELEX Septal Occluder for transcatheter closure of patent foramen ovale: multicentre experience.

Patients with cryptogenic embolic events and a patent foramen ovale (PFO) are at risk of paradoxical embolism causing recurrent cerebral events; however, transcatheter PFO closure remains controversial. The aim of this multicentre trial was to demonstrate the feasibility and safety of transcatheter closure of PFO with the HELEX Septal Occluder. The study enrolled 128 patients (66 female; mean age, 50 years). Mean (+/-SD) PFO size was 10+/-3.7 mm; 38 patients also had an atrial septal aneurysm. Device implantation was successful in 127 patients. Device-related events during implantation or follow-up were device embolisation, wire-frame fracture, and retrieval cord breaks (two cases each; no sequelae). Other adverse events included atrial arrhythmia (two patients), migraine, convulsion, and transient ischaemic attack (one case each). There were no recurrent strokes, deaths, perforations, or accumulations of thrombi on the device. Within a mean follow-up period of 21+/-11 months, complete PFO closure using one device was achieved in 114 patients (90%). Five patients with a moderate to large residual shunt received a second device. The HELEX Occluder can be used for PFO closure. Device- and procedure-related complications are rare. The closure procedure appears to reduce recurrence rates of stroke and transient ischaemic attack.

MRT-Sicherheitsaspekte und -Artefakte von Vorhofseptum-Okkludersystemen bei 1,5 Tesla: eine Phantomstudie

To investigate the magnetic resonance safety and magnetic resonance artifact intensities of patent foramen ovale and atrial septal occluders in a phantom study. Seven different commercial occluder models (Amplatzer ASD, Angel Wing ASD, Helex Septal Occluder, Cardia PFO-Star Generation I & III, Sideris Buttoned Device, Starflex ASD) were tested in a 1.5 Tesla whole-body MR scanner. Following a deflection test, the non-magnetic devices were imaged using different MRI pulse sequences including conventional spin echo, spoiled gradient echo as well as fast refocused steady-state pulse sequences (trueFISP) commonly used for cardiac MRI. Additionally, device temperatures were measured in the MR scanner during two imaging protocols (trueFISP, HASTE) with an MR-compatible fiber-optical thermometer. One ferromagnetic device (Sideris Buttoned Device) did not pass the deflection test and was excluded from further experiments. For typical cardiac imaging protocols, the remaining non-ferromagnetic devices showed only minor image artifacts with artifact sizes not exceeding 2 mm next to a strut. Heating was not observed in the devices. Non-ferromagnetic occluder models used in this study can safely be imaged with typical cardiac MRI protocols at 1.5 Tesla. The device artifact sizes are small enough to allow anatomical and functional MRI even in the immediate vicinity of the occluders.

Technical considerations for closing secundum atrial septal defect in the small child with the HELEX septal occluder via transhepatic access

We describe closure of an atrial septal defect in a symptomatic 4.6 kg child with the HELEX Septal Occluder (W.L. Gore and Associates, Flagstaff, AZ) via transhepatic approach. Technical considerations are discussed.

Initial experience in Brazil with the Helex septal occluder for percutaneous occlusion of atrial septal defects.

To evaluate the initial clinical experience with the Helex septal occluder for percutaneous closure of atrial septal defects. Ten patients underwent the procedure, 7 patients with ostium secundum atrial septal defects (ASD) with hemodynamic repercussions and 3 patients with pervious foramen ovale (PFO) and a history of stroke. Mean age was 33.8 years and mean weight was 55.4 kg. Mean diameter by transesophageal echocardiography and mean stretched ASD diameter were 11.33 3.3mm, and 15.2 3.8mm, respectively. The Qp/Qs ratio was 1.9 0.3 in patients with ASD. Eleven occluders were placed because a patient with 2 holes needed 2 devices. It was necessary to retrieve and replace 4 devices in 3 patients. We observed immediate residual shunt (< 2mm) in 4 patients with ASD, and in those with patent foramen ovale total occlusion of the defect occurred. No complications were noted, and all patients were discharged on the following day. After 1 month, 2 patients with ASD experienced trivial residual shunts (1mm). In 1 patient, we observed mild prolapse in the proximal disk in the right atrium, without consequences. The Helex septal occluder was safe and effective for occluding small to moderate atrial septal defects. Because the implantation technique is demanding, it requires specific training of the operator. Even so, small technical failures may occur in the beginning of the learning curve, but they do not involve patient safety.

Echocardiographic considerations during deployment of the Helex Septal Occluder for closure of atrial septal defects

The Helex Septal Occluder is a new device used to close atrial septal defects via interventional catheterization. In order to study the role of echocardiography during its use, and to describe the morphologic variants of defects suitable for closure with this occluder, we evaluated all patients undergoing intended closure of an atrial septal defect with the Helex occluder. A combination of transthoracic, transesophageal, three-dimensional, and intracardiac echocardiography were used before, during, and after the procedure to characterize anatomy, assess candidacy for closure, guide the device during its deployment, and evaluate results. Among the 60 candidates included in the study, 11 were excluded because of transesophageal echocardiographic and/or catheterization data obtained in the laboratory. Attempts at closure were successful in 46 patients, and unsuccessful in 3. We successfully treated four types of defects. These were defects positioned centrally within the oval fossa with appreciable rims along the entire circumference of the defect, defects with deficient or absent segments of the rim, defects with aneurysm of the primary atrial septum, and defects with multiple fenestrations. Follow-up transthoracic echocardiograms taken at a median of 7 months demonstrated no residual defects in 21, trivial residual defects in 17, and small residual defects in 8 patients. In 20 patients, three-dimensional reconstructions were used to characterize the morphology of the defect and the position of the device. Because transesophageal echocardiography was often limited by acoustic interference from the device, intracardiac echocardiography was utilized in 3 cases to overcome this limitation.

Development and testing of the Helex septal occluder, a new expanded polytetrafluoroethylene atrial septal defect occlusion system.

A variety of transcatheter atrial septal defect (ASD) occluders are currently in use around the world. Although for the most part effective, all of these devices lack features that would be desirable in a "perfect" device. The Helex septal occluder is a new type of device designed to improve the results of transcatheter ASD closure. This study was designed to examine the effectiveness and safety of this occluder in an animal model. The Helex was implanted into 24 dogs with surgically created ASDs. Procedural details focusing on deployment, removal, and early closure rates were examined. Follow-up consisted of sequential transesophageal echocardiography and fluoroscopy as well as epicardial contrast echocardiography and angiography at the time of death. Specimens were examined grossly and histologically, and devices were tested for metal fatigue. All animals had successful ASD closure. Implantation was uncomplicated (mean fluoroscopy time 11.7 minutes), and removal or repositioning was always possible. Closure rate as judged by transesophageal echocardiography was 88% initially and 100% at 2-week follow-up. Devices rapidly became infiltrated with connective tissue without inflammation and were endothelialized over time. There were no instances of thromboembolism. A single wire-frame fracture occurred secondary to a prototype delivery system malfunction. The Helex septal occluder proved safe and effective for ASD closure. Several advantages over currently available devices were evident in this model. Controlled prospective clinical trials are needed.