Current perspectives in percutaneous atrial septal defect closure devices

Assessment of degradability and endothelialization of modified poly L-lactic acid (PLLA) atrial septal defect (ASD) occluders over time in vivo

OBJECTIVE

To evaluate the fiber-degradation and endothelialization of a modified poly L-lactic acid (PLLA) atrial septal defect (ASD) occluder for a long time in vivo.

METHODS

A total of 57 New Zealand rabbits were selected to establish the vasculature implantation model, which would be used to characterize the mechanical properties and pathological reaction of PLLA filaments (a raw polymer of ASD occluder). In total, 27 Experimental piglets were used to create the ASD model for the catheter implantation of PLLA ASD occluders. Then, X-ray imaging, transthoracic echocardiography, histopathology, and scanning electron microscope (SEM) were performed in the experimental animals at 3, 6, 12, and 24 months after implantation.

RESULTS

In the rabbit models, the fibrocystic grade was 0 and the inflammatory response was grade 2 at 6 months after vasculature implantation of the PLLA filaments. The mass loss of PLLA filaments increased appreciably with the increasing duration of implantation, but their mechanical strength was decreased without broken. In the porcine models, the cardiac gross anatomy showed that all PLLA ASD occluders were stable in the interatrial septum without any vegetation or thrombus formation. At 24 months, the occluders had been embedded into endogenous host tissue nearly. Pathological observations suggested that the occluders degraded gradually without complications at different periods. SEM showed that the occluders were endothelialized completely and essentially became an integral part of the body over time.

CONCLUSION

In the animal model, the modified PLLA ASD occluders exhibited good degradability and endothelialization in this long-term follow-up study.

Healing the Broken Hearts: A Glimpse on Next Generation Therapeutics

Cardiovascular diseases are the leading cause of death worldwide, accounting for 32% of deaths globally and thus representing almost 18 million people according to WHO. Myocardial infarction, the most prevalent adult cardiovascular pathology, affects over half a million people in the USA according to the last records of the AHA. However, not only adult cardiovascular diseases are the most frequent diseases in adulthood, but congenital heart diseases also affect 0.8–1.2% of all births, accounting for mild developmental defects such as atrial septal defects to life-threatening pathologies such as tetralogy of Fallot or permanent common trunk that, if not surgically corrected in early postnatal days, they are incompatible with life. Therefore, both congenital and adult cardiovascular diseases represent an enormous social and economic burden that invariably demands continuous efforts to understand the causes of such cardiovascular defects and develop innovative strategies to correct and/or palliate them. In the next paragraphs, we aim to briefly account for our current understanding of the cellular bases of both congenital and adult cardiovascular diseases, providing a perspective of the plausible lines of action that might eventually result in increasing our understanding of cardiovascular diseases. This analysis will come out with the building blocks for designing novel and innovative therapeutic approaches to healing the broken hearts.

Transcatheter closure of secundum atrial septal defect using Cocoon septal occluder: immediate and long-term results

Background

Atrial septal defect (ASD) is one of the common congenital heart defects. Its management has transformed dramatically in the last 4 decades with the transition from surgical to percutaneous transcatheter closure for most secundum-type ASDs. Various devices are available for transcatheter closure of ASD with Amplatzer atrial septal occluder being most commonly used worldwide. Cocoon septal occlude has a nanocoating of platinum using nano-fusion technology over nitinol framework that imparts better radiopacity and excellent biocompatibility and prevents leaching of nickel into circulation, and by smoothening nitinol wire makes this device very soft and smooth. The aim of this study was to evaluate feasibility, effectiveness, safety, and long-term outcome of transcatheter closure of ASD using Cocoon septal occluder (Vascular Innovation, Thailand).

Results

All patients undergoing transcatheter closure of hemodynamically significant ASD between September 2012 and July 2019 in our institute were included into this single-center, prospective study. Exclusion criteria were defect > 40 mm, unsuitable anatomy, Eisenmenger syndrome, and anomalous pulmonary venous return. Three hundred and twenty patients underwent device closure, of which 238 (74%) were female. The mean age was 14.6 years (range 6–29), and the median weight was 30.2 kg (range 10–53 kg). Procedure was performed under fluoroscopy using transthoracic and transesophageal echocardiography in 298 (93.1%) and 22(6.9%) patients, respectively. Balloon-assisted technique was used, when septal defect was ≥ 34 mm, in 9 (2.8%) patients. The mean diameter of defect and device was 21.4 mm (range 12–36 mm) and 26.9 mm (range 14–40 mm), respectively. Aortic rim was absent in 11 (3.4%) patients. Primary success was achieved in 312 (97.5%) patients. Early embolization to right ventricle was noted in 2 (0.6%) patients. In both cases, 40-mm device was attempted for defect of 36 mm with inadequate aortic rim using balloon-assisted technique. One (0.3%) patient developed perforation of right atrium. All were surgically repaired. Three (0.9%) patients developed complete heart block following device deployment requiring device retrieval. Two patients had had moderate residual shunt at 6 months of follow-up. After mean follow-up of 50.92 months (range 12.5–89 months), no erosion, allergic reactions to nickel, or other major complications were reported.

Conclusions

Percutaneous transcatheter closure of ASD by Cocoon septal occluder (up to 36 mm) is safe and feasible with high success rate and without any significant device-related major complications over long-term follow-up. With unique device design and excellent long-term safety, it could be preferred dual-disk occluder for transcatheter closure of atrial septal defect. In most of the patients, ASD device can be safely deployed under transthoracic echocardiographic guidance.

Nickel hypersensitivity and endovascular devices: a systematic review and meta-analysis

OBJECTIVE

Nickel allergy is common; endovascular specialists are often confronted with nickel allergic patients ahead of the implantation of endovascular devices, many of which are nickel-containing. Our aim was to elucidate whether nickel hypersensitivity is significantly associated with worse or adverse outcomes after placement of a nickel-containing endovascular device.

METHODS

Inclusion criteria were: endovascular and transcatheter procedures for coronary, structural heart, neurovascular and peripheral vascular pathology involving nickel-allergic patients. All adverse outcomes were included as defined by included studies. A systematic review and meta-analysis were undertaken using a random-effects model. Searches of MEDLINE and EMBASE were conducted for articles published 1947-2019.

RESULTS

190 records were identified, 78 articles were included for qualitative synthesis and 15 met criteria for meta-analysis. Patch-test confirmed nickel allergy was associated with an increased risk of adverse outcomes following implantation of a nickel-containing endovascular device (n=14 articles, 1740 patients; OR 2.61, 95% CI 1.41 to 4.85). This finding further was observed in coronary (n=12 articles, 1624 patients; OR 1.94, 95% CI 1.16 to 3.23) and structural heart subgroups (n=2 articles, 83 patients; OR 52.28, 95% CI 1.31 to 2079.14), but not in the neurovascular subgroup (n=1 article, 33 patients; OR 3.04, 95% CI 0.59 to 15.72) or with a patient-reported history of nickel allergy (n=2 articles, 207 patients; OR 2.14, 95% CI 0.23 to 19.70).

CONCLUSIONS

Patch-tested nickel allergy is associated with an increased risk of adverse outcomes following endovascular device implantation and alternative treatment options should be considered. Specialists faced with patients' self-reporting nickel allergy should consider proceeding to diagnostic patch-testing.

Late Bacterial Endocarditis in an Intravenous Drug User With an Amplatzer Septal Occluder

Infective endocarditis of a fully endothelialized cardiac prosthesis, and especially the late presentation of endocarditis, challenges our current understanding of device-related complications. Late bacterial endocarditis associated with the Amplatzer Septal Occluder, a device frequently used to close atrial septal defects, has been documented only rarely. We report the case of an intravenous drug user who had late infective endocarditis associated with his Amplatzer Septal Occluder, secondary to methicillin-sensitive Staphylococcus aureus bacteremia nearly 14 years after device insertion. The patient recovered after surgical excision and débridement of the vegetative mass, which may be the first time that a surgical approach has been taken to treat this condition. This report corroborates the need for late screening of high-risk patients who have septal occluder devices.

Atrio-aortic erosion caused by Amplatzer Atrial Septal Occluder - a case report

Background

In specialized centers, percutaneous closure using specific occluders is the first-choice treatment in atrial septal defects (ASD). Late complications after this intervention, such as erosion of the aorta or the atria, are rare and have not been sufficiently approached and dealt with in literature. In our clinic we have been faced with the problematic situation of diagnosing and treating such cases. That is why, we have decided to share our experience with other colleagues.

Case presentation

We present two cases of severe late complications after percutaneous closure of atrial septal defects (ASD). In both cases, the atrial septal occluder (Amplatzer™ Atrial Septal Occluder Device, Abbott, Chicago USA) caused the erosion between the left atrium and the aortic root. The atrio-aortic erosion led to acute cardiac tamponade with upper venous congestion and shock. As the bleeding source remained undetectable for any imaging tools, a diagnostical sternotomy remained the only solution.

The cause of the acute bleeding was discovered to be the erosion between the left atrium and the aortic root. The treatment consisted in the removal of the occluder, direct suturing of the perforated areas and the surgical closure of the remaining ASD. The patients fully recovered within the nine to fourteen days’ hospital stay. Six months after surgery both patients were well and able to recover their daily routine.

Conclusions

The atrio-aortic erosion after percutaneous closure of atrial septal defects is a surgical emergency. The more so, since it can be complicated by the absence of specific symptoms. A key-element in the diagnosis of this rare pathology remains the medical history of the patient, which the surgeon has to consider thoroughly and launch the diagnostic sternotomy without delay.

The Future of Paediatric Heart Interventions: Where Will We Be in 2030?

Purpose of Review

Cardiac catheterization therapies to treat or palliate infants, children and adults with congenital heart disease have developed rapidly worldwide in both technical innovation and device development in the previous three decades. By reviewing of current status of novel or development of devices and techniques, we will discuss what is likely to happen in paediatric heart intervention in the next decade.

Recent Findings

Recently, biodegradable stents and devices, transcatheter pulmonary valve implantation for the native right ventricle outflow tract and MRI-guided interventions have been progressing rapidly with good immediate to early results. These are expected to be introduced and spread in the next decade although there are still challenges to overcome.

Summary

The future of paediatric heart intervention is very promising with rapid development of technological progress.

Comparison of Figulla Flex® and Amplatzer™ devices for atrial septal defect closure: A meta-analysis

BACKGROUND

Atrial septal defect (ASD) is one of the most common congenital heart diseases. Percutaneous closure is the preferred treatment, but certain complications remain a concern. The most common devices are AMPLATZER™ (ASO) (St. Jude Medical, St. Paul, MN, USA) and Figulla Flex® septal occluders (FSO) (Occlutech GmbH, Jena, Germany). The present study aimed to assess main differences in outcomes.

METHODS

A systematic search in Pubmed and Google scholarship was performed by two independent reviewers for any study comparing ASO and FSO. Searched terms were "Figulla", "Amplatzer", and "atrial septal defect". A random-effects model was used.

RESULTS

A total of 11 studies including 1770 patients (897 ASO; 873 FSO) were gathered. Baseline clinical and echocardiographic characteristics were comparable although septal aneurysm was more often reported in patients treated with ASO (32% vs. 25%; p = 0.061). Success rate (94% vs. 95%; OR: 0.81; 95% CI: 0.38-1.71; p = 0.58) and peri-procedural complications were comparable. Procedures were shorter, requiring less fluoroscopy time with an FSO device (OR: 0.59; 95% CI: 0.20-0.97; p = 0.003). Although the global rate of complications in long-term was similar, the ASO device was associated with a higher rate of supraventricular arrhythmias (14.7% vs. 7.8%, p = 0.009).

CONCLUSIONS

Percutaneous closure of ASD is a safe and effective, irrespective of the type of device. No differences exist regarding procedural success between the ASO and FSO devices but the last was associated to shorter procedure time, less radiation, and lower rate of supraventricular arrhythmias in follow-up. Late cardiac perforation did not occur and death in the follow-up was exceptional.

Trends in the Prevalence of Atrial Septal Defect and Its Associated Factors among Congenital Heart Disease Patients in Vietnam

Atrial septal defect (ASD) is a non-physiologic communication between the two atria, allowing the shunt between systemic and pulmonary circulation. Data about ASD prevalence among congenital heart disease patients (CHD) in Vietnam are still scarce. We aim to assess the trends in the prevalence of ASD patients and associated factors among CHD patients. This was a cross-sectional study, with data collected from medical records from 1220 CHD patients in Da Nang hospital from 1 January 2010 to 31 December 2015. Descriptive statistics were used to estimate the prevalence of ASD among CHD patients. Comparative statistical methods were used to compare groups and logistic regression to access associated factors with ASD. The overall prevalence of ASD among CHD patients was 18.5% between 2010 and 2015. The prevalence varied between periods, ranging between 15% and 31.9% during the period. The prevalence of ASD women among CHD (25.9%) was significantly higher than for men (16.0%). The prevalence of ASD increased gradually when the age group increased. The factors associated with increased ASD prevalence were being a female and being in an older age group. The findings suggest that targeted policy should provide more-specific health-care services of ASD for women and older patients.

Biodegradable atrial septal defect occluders: A current review

Atrial septal defect (ASD) is a common structural congenital heart disease. With the development of interventional closure devices and transcatheter techniques, interventional closure therapy has become the most well-accepted therapeutic alternative worldwide, as it offers a number of advantages over conventional therapies such as improved safety, easier operation, lower complication rates and invasiveness, and shorter anesthetic time and hospitalizations. During the past decades, various types of occluders based on nondegradable shape memory alloys have been used in clinical applications. Considering that the permanent existence of foreign nondegradable materials in vivo can cause many potential complications in the long term, the research and development of biodegradable occluders has emerged as a crucial issue for interventional treatment of ASD. This review aims to summarize partially or fully biodegradable occlusion devices currently reported in the literature from the aspects of design, construction, and evaluation of animal experiments. Furthermore, a comparison is made on the advantages and disadvantages of the materials used in biodegradable ASD occlusion devices, followed by an analysis of the problems and limitations of the occlusion devices. Finally, several strategies are proposed for future development of biodegradable cardiac septal defect occlusion devices. STATEMENT OF SIGNIFICANCE: Although occlusion devices based on nondegradable alloys have been widely used in clinical applications and saved numerouspatients, biodegradable occlusion devices may offer some advantages such as fewer complications, acceptable biocompatibility, and particularly temporary existence, thereby leaving "native" tissue behind, which will certainly become the development trend in the long term. This review summarizes almost all partially or fully biodegradable occlusion devices currently reported in the literature from the aspects of design, construction, and evaluation of animal experiments. Furthermore, a comparison is made on the advantages and disadvantages of the materials used in biodegradable ASD occlusion devices, followed by an analysis of the problems and limitations of the occlusion devices. Finally, several strategies are proposed for future development of biodegradable cardiac septal defect occlusion devices.

Role of animal models for percutaneous atrial septal defect closure

As for any preclinical development of new implantable device, bench testing has been followed by experimental studies on large animal models for the development of atrial septal defect closure devices. Various models have been used according to studied species (porcine, ovine or canine model) and whether the septal defect was percutaneously or surgically created. Animal models of percutaneous atrial septal defect closure aim to assess the healing process and device endothelialisation, as well as the development of magnetic resonance imaging guided procedures, the short-term effects of volume overload on right ventricular contractility through haemodynamic studies and the understanding of other complications such as nickel hypersensitivity. Each technique has its own advantages and drawbacks, and leads to different punch-related, acute septal injuries that could have an effect on the healing process after device implantation. It has been suggested that some long-term, major device-related complications such as thrombosis or infective endocarditis may be associated with an inappropriate healing process or insufficient endothelialisation of the device, leading industrial companies to pay a great deal of attention to the healing process. Tissue reactions in animal models were shown to adequately reproduce the healing response after device implantation in humans, with an endothelial device coverage observed as early as 30 days after implantation and complete after 3 to 6 months. Research perspectives may evaluate both animal models and in-vitro studies in parallel with a view to clarify the endothelialisation process using human endothelial cells through in-vitro experiments. Self-sensing device for detecting the presence of endothelial cells on the surface of intracardiac occluders and high-resolution imaging techniques that could non-invasively assess the complete endothelialisation of a device would also be promising tools which would need large animal models studies before their clinical application.

Study of biodegradable occluder of atrial septal defect in a porcine model

Objective

To evaluate the safety and feasibility of a modified poly(l‐lactic acid) (PLLA) atrial septal defect (ASD) occluder.

Methods

Forty‐five piglets were divided into two groups: an experimental group (n = 27) and a control group (n = 18). The experimental group underwent percutaneous implantation of a modified PLLA ASD device while the control group underwent percutaneous implantation of a widely used metal ASD device. X‐ray imaging, transthoracic echocardiography (TTE), electrocardiogram (ECG), histopathology and electron microscopic examination were performed at 7 days, 1, 3, 6, and 12 months after implantation.

Results

Twenty‐seven experimental piglets and 18 control piglets were all successfully implanted with modified biodegradable and metal ASD devices, respectively. While both devices exhibited very good occluding effects, the modified PLLA ASD devices were completely endothelialized at 3 months after implantation, and the endothelialization appeared to be more complete compared to the control group. Degradation of the PLLA devices was noted at 12 months follow‐up with no loss of integrity at the atrial septum.

Conclusion

This animal model with implanting of the occluders was effective and not associated with complications. The modified PLLA ASD devices are more controllable and practical than our previous devices. The implanted devices demonstrated good endothelialization and degradability in short and moderate term follow‐up. Long‐term studies are now underway to further evaluate the biodegradability of this novel device.

Atrial septal defect (ASD) device trans-catheter closure: limitations

Transcatheter closure is a widespread technique used to treat secundum atrial septal defects (ASDs). When compared to surgery, it provides a less invasive approach with quicker recovery and reduced physical and psychological impact. Nowadays, almost 85-90% of all secundum ASD can be closed by using a transcatheter approach. However, several limitations may have a significant impact on the feasibility and success of percutaneous ASD closure. Limitations can be grouped as: (I) anatomical; (II) device-related; (III) associated defects and natural history associated issues; (IV) physiological; (V) complications. Physician should be aware of potential limits of percutaneous ASD closure.

Interventional Echocardiography: Field of Advanced Imaging to Support Structural Heart Interventions

Multimodality imaging, particularly echocardiography, is paramount in planning and guiding structural heart disease interventions. Transesophageal echocardiography remains unique in its ability to provide real-time 2D and 3D imaging of valvular heart disease and anatomic cardiac defects, which directly impacts the strategy and outcome of these procedures. This review summarizes the role of transesophageal echocardiography in patients undergoing the most common structural heart disease interventions.

Tough, but not impossible - Retrieval of large atrial septal occluder devices embolized to left atrium

Atrial septal defect (ASD) is a congenital heart defect that is being increasingly treated using percutaneous interventions. However, these techniques are not devoid of complications. One such complication is device embolization. Removal of such closure device poses tremendous risk and consequent complications both by percutaneous retrieval and surgical removal. Herein, we present two cases of ASDs that were closed using atrial septal occluder, but the devices were subsequently embolized into left atrium. These devices were then percutaneously retrieved without any further complication or injury.

Translation in cardiovascular stents and occluders: From biostable to fully degradable

Cardiovascular disease is a major cause of morbidity and mortality, especially in developed countries. Most academic research efforts in cardiovascular disease management focus on pharmacological interventions, or are concerned with discovering new disease markers for diagnosis and monitoring. Nonpharmacological interventions with therapeutic devices, conversely, are driven largely by novel materials and device design. Examples of such devices include coronary stents, heart valves, ventricular assist devices, and occluders for septal defects. Until recently, development of such devices remained largely with medical device companies. We trace the materials evolution story in two of these devices (stents and occluders), while also highlighting academic contributions, including our own, to the evolution story. Specifically, it addresses not only our successes, but also the challenges facing the translatability of concepts generated via academic research.