Patent foramen ovale closure using a bioabsorbable closure device: safety and efficacy at 6-month follow-up

Atrial Fibrillation After Patent Foramen Ovale Closure: Incidence, Pathophysiology, and Management

This comprehensive review explores the incidence, pathophysiology, and management of atrial fibrillation (AF) following percutaneous closure of patent foramen ovale (PFO). Although AF is considered a common adverse event post PFO closure, its incidence, estimated at <5%, varies based on monitoring methods. The review delves into the challenging task of precisely estimating AF incidence, given subclinical AF and diverse diagnostic approaches. Notably, a temporal pattern emerges, with peak incidence around the 14th day after closure and a subsequent decline after the 45th day, mimicking general population AF trends. The pathophysiological mechanisms behind post PFO closure AF remain elusive, with proposed factors including local irritation, device-related interference, tissue stretch, and nickel hypersensitivity. Management considerations encompass rhythm control, with flecainide showing promise, and anticoagulation tailored to individual risk profiles. The authors advocate for a personalized approach, weighing factors like age, comorbidities, and device characteristics. Notably, postclosure AF is generally considered benign, often resolving spontaneously within 45 days, minimizing thromboembolic risks. Further studies are required to refine understanding and provide evidence-based guidelines.

Progress of biodegradable polymer application in cardiac occluders

Cardiac septal defect is the most prevalent congenital heart disease and is typically treated with open-heart surgery under cardiopulmonary bypass. Since the 1990s, with the advancement of interventional techniques and minimally invasive transthoracic closure techniques, cardiac occluder implantation represented by the Amplazter products has been the preferred treatment option. Currently, most occlusion devices used in clinical settings are primarily composed of Nitinol as the skeleton. Nevertheless, long-term follow-up studies have revealed various complications related to metal skeletons, including hemolysis, thrombus, metal allergy, cardiac erosion, and even severe atrioventricular block. Thus, occlusion devices made of biodegradable materials have become the focus of research. Over the past two decades, several bioabsorbable cardiac occluders for ventricular septal defect and atrial septal defect have been designed and trialed on animals or humans. This review summarizes the research progress of bioabsorbable cardiac occluders, the advantages and disadvantages of different biodegradable polymers used to fabricate occluders, and discusses future research directions concerning the structures and materials of bioabsorbable cardiac occluders.

Favorable mid-term performance of fully biodegradable implantable device for ventricular septal defect closure

Objectives

To assess the mid-term safety and efficacy of transthoracic perimembranous ventricular septal defect (Pm-VSD) closure using a new biodegradable device. Implantation entailed right subaxillary minithoracotomy under transesophageal echocardiography guidance.

Methods

Between October 2019 and January 2020, 13 patients (males, 5; mean age, 3.6 ± 2.5 years) with Pm-VSDs underwent transthoracic device closures at Zhengzhou University Central China Fuwai Hospital as described previously. Delivery pathways were established by manipulating a hollow probe from right atrium through tricuspid valve to right ventricle and then through VSDs to left ventricle, whereupon installation took place.

Results

All occluder implantations were successfully executed. Mean defect size was 4.1 ± 1.0 mm, and mean device waist size was 5.2 ± 1.1 mm. One patient (7.7%) with 1.5-mm residual shunt showed complete closure at discharge. There was 1 instance of postoperative incomplete right bundle branch block, which converted to complete right bundle branch block at month 1. During patient follow-up (mean, 24.6 ± 0.8 months), no device dislocations, new residual shunts, new valvular regurgitation, or detectable atrioventricular block ensued.

Conclusions

Closure of Pm-VSDs using a novel, fully biodegradable occluder in the manner described has proven safe and effective at mid-term follow-up. Long-term safety and efficacy of this device must be further corroborated in a large patient cohort going forward.

Initial Clinical Experience with the Biodegradable AbsnowTM Device for Percutaneous Closure of Atrial Septal Defect: A 3-Year Follow-Up

Objective

We reported the 3-year follow-up results of initial clinical experience with the Absnow^TM device, a novel biodegradable occluder for percutaneous closure of atrial septal defect (ASD).

Background

The Absnow^TM device is a total biodegradable septal occluder with double-disc poly-L-lactic acid (PLLA) framework and PLLA membranes intergraded into the device to ensure its biodegradability, clinical safety, and efficacy.

Methods

Five pediatric patients were enrolled from May to June 2018 in our institution and were followed up for 3 years. A clinical evaluation and transthoracic echocardiography were performed at 24 hr, 1 month, 3 months, 6 months, 12 months, and yearly after implantation. Primary endpoints were a composite clinical success, comprising of clinical closure success and safety at the 36-month follow-up evaluation. Secondary endpoints included technical success, procedure success, closure success, and safety at each of the follow-up visits.

Results

The median subject age was 3.6 years (range 3.1-6.5 years). The mean ASD diameter was (13.7 ± 2.9) mm. The median device size was 20 mm (range 14 to 24 mm). Technical and procedure success was achieved in 100% (5/5) of the patients. At 2-year follow-up, 3 of the 5 patients developed new-onset residual shunts and 2 of them reached a moderate degree. At 3-year follow-up, the residual shunt size increased over time in all the 3 patients, and 1 of them had right ventricular enlargement. All of the 5 patients were free from serious adverse events during the 3-year follow-up, with no device embolization, thromboembolization, or reintervention to the target defect.

Conclusion

This 3-year follow-up result of initial experience with the biodegradable Absnow^TM device has demonstrated acceptable safety with no procedural complications. Notably, the high rate of residual shunt significantly affected its efficacy. The long-term safety and efficacy of the device should be further evaluated in a large cohort of patients in future studies.

Role of PFO Closure in Ischemic Stroke Prevention

PURPOSE OF REVIEW

To highlight recent advancements in the management of acute ischemic stroke patients with patent foramen ovale (PFO).

RECENT FINDINGS

One significant recent development was publication of long-term follow-up data from the RESPECT trial demonstrating evidence in favor of PFO closure over medical management. This data subsequently led to FDA approval for AMPLATZER™ septal occluder in the treatment of patients aged 18 to 60 years with both PFO and no other determined etiology for ischemic stroke, otherwise referred to as embolic stroke of undetermined source. Several subsequent closure trial results have recently been published, which also demonstrated benefit of PFO closure over medical management for ischemic stroke risk reduction in select patients. Based on the results of the more recently published REDUCE trial, the FDA granted approval for the GORE™ septal occluder. There is current, well-established evidence that PFO closure for secondary stroke prevention is effective in select cases.

Initial experiences with a novel biodegradable device for percutaneous closure of atrial septal defects: From preclinical study to first-in-human experience

Objective

To evaluate the feasibility, safety, and effectiveness of a novel, absorbable atrial septal defect (ASD) closure device made of poly‐l‐lactic acid (PLLA) in a swine model of ASD and for the first time in humans.

Methods

A preclinical safety study was conducted using a swine model of ASD. In a clinical setting, five pediatric patients underwent ASD closure with the PLLA device with fluoroscopic and transthoracic echocardiography guidance. The procedural results and clinical outcomes at 1 day, 30 days, 3 months, and 6 months after closure were analyzed.

Results

The 24‐ and 36‐month follow‐up results of the preclinical study demonstrated that the PLLA device exhibited good endothelialization and degradability in the swine model. In the clinical study, successful device implantation was achieved in all five patients (median age, 3.6 years; range, 3.1–6.5 years). The mean defect size was (13.6 ± 2.7) mm. Follow‐up at 30 days, 3 months, and 6 months was completed in all five cases. The complete defect closure rates with no residual shunt at 30 days, 3 months, and 6 months follow‐up were 60% (3/5), 80% (4/5), and 80% (4/5), respectively. No device dislodgement, significant aortic valve or mitral valve regurgitation, new onset cardiac arrhythmia, or other adverse events were reported.

Conclusion

The study results demonstrated that it is feasible to implant the PLLA device for closure of small to medium sized ASDs without significant residual shunts or severe adverse events in humans. The PLLA device exhibited good endothelialization and degradability in the swine model at 24 and 36 months. Further studies to evaluate long‐term safety and effectiveness with the device in a large cohort of patients are warranted.

Long-term transesophageal echocardiography after patent foramen ovale closure by BioSTAR and Amplatzer patent foramen ovale occluders

OBJECTIVES

To compare transesophageal echocardiography (TOE) findings after patent foramen ovale (PFO) closure by BioSTAR (NMT Medical Inc, Boston, MA) and Amplatzer PFO occluders (Abbott Vascular, Plymouth, MN).

BACKGROUND

PFO closure with a biodegradable device represents an attractive alternative to permanent devices. Long-term effectiveness and morphology after biodegradation remain unknown.

METHODS

Between February 2008 and June 2014, 49 patients received BioSTAR and 48 Amplatzer PFO occluder. TOE was performed after closure, at 6 months and beyond 2 years.

RESULTS

PFO features were comparable between the groups. Immediate effective closure (<5 bubbles on Valsalva) was obtained in 96% by BioSTAR and 88% by Amplatzer PFO occluder (p = .16). Except for transient fever after BioSTAR (10.8 vs. 0%; p = .08), there was no adverse events. TOE at 6 months revealed comparable effective closure (93 vs. 89%; p = .74), all devices in correct position and no thrombus/pericardial effusion. In the BioSTAR group, a peri-device left-to-right color Doppler shunt was documented in one patient (2.2%), protrusion of the nitinol framework strut(s) into the atrial cavity in two patients (4.3%), and both events in one patient (2.2%). TOE beyond 2 years showed comparable effective closure (92 vs. 96%; p = 1.00) and again BioSTAR-associated peri-device left-to-right shunt and metal framework strut(s) protrusion. There was no stroke or peripheral embolization in either group while TIA was numerically greater in BioSTAR patients (6.8 vs. 2.5%; p = .61).

CONCLUSION

BioSTAR provided similar PFO closure rate as Amplatzer PFO occluder. As yet unreported BioSTAR-associated peri-device left-to-right shunt and metal framework strut(s) protrusion may have practical implications for further development of biodegradable devices.

Sleep Apnea in Patients with and without a Right-to-Left Shunt

OBJECTIVES

To assess the presence of right-to-left shunting (RLS) in patients with obstructive sleep apnea (OSA), and compare clinical characteristics and parameters of the sleep studies of patients with and without RLS.

BACKGROUND

The most common cause of RLS is due to intermittent flow through a patent foramen ovale (PFO). PFO occurs more frequently in patients with OSA and may be involved in the exacerbation of OSA.

METHODS

Patients with an abnormal polysomnogram seen at UCLA-Santa Monica Sleep Medicine Clinic were enrolled. A diagnosis of RLS was made using a transcranial Doppler (TCD) bubble study. Gender and age-matched controls were drawn from patients referred for cardiac catheterization who underwent a TCD. The frequency of RLS in OSA patients and the controls was evaluated. Clinical characteristics and polysomnogram parameters were compared between OSA patients with and without a RLS.

RESULTS

A total of 100 OSA patients and 200 controls participated in the study. The prevalence of RLS was higher in patients with OSA compared to the control group (42% versus 19%; p < 0.0001). Patients with OSA and a RLS had a lower apnea-hypopnea index (AHI), less obstructive apnea, and fewer hypopnea episodes than patients with OSA without a RLS. The baseline and nadir SpO2 were similar in both groups and did not correlate with the level of RLS assessed by TCD. The degree of desaturation for a given respiratory disturbance, as measured by oxygen desaturation index (ODI)/AHI ratio, was higher in OSA patients with RLS versus OSA patients without RLS (0.85 ± 0.07 versus 0.68 ± 0.04; p < 0.0001).

CONCLUSION

RLS, most commonly due to a PFO, occurs 2.2 times more frequently in OSA patients compared to a control population that was matched for age and gender. The severity of sleep apnea is not greater in OSA patients who have a PFO. However, patients with OSA and a PFO are more likely to become symptomatic at a younger age with an equivalent decrease in nocturnal SpO2, and have greater arterial desaturation in proportion to the frequency of respiratory disturbances.

Animal experimental study of the fully biodegradable atrial septal defect (ASD) occluder

This study was conducted to evaluate the feasibility, safety, biocompatibility, and degradation features of a fully biodegradable occluder for closure of atrial septal defect (ASD) in an acute canine model. The ASD was created in 20 healthy mongrel dogs by the brockenbrough needle, and the fully biodegradable occluders were implanted by self-made delivery system. The success rate and complications were observed. Acute ASD models were successfully created in 18 dogs, and 16 occluders were successfully implanted in the ASD models. Animals were sacrificed at different times after procedure. The cardiac gross anatomy showed that all occluders were stable in the interatrial septum, no vegetation or thrombus formation was observed on the surface of all occluders. They were embedded into endogenous host tissue gradually at 12-week follow-up. Different periods of pathological observations suggested that the occluders degraded gradually over about 24 weeks and essentially became an integral part of the septum. Transcatheter closure of ASD in acute canine model using the fully biodegradable ASD occluder has the potential of a high successful rate of technique, excellent biocompatibility, and fewer complications with adequate, immediate, and short-term results.