BioSTAR Evaluation STudy (BEST)

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.

A new echocardiographic index to select patients for PFO suture-mediated percutaneous closure

OBJECTIVES

To identify a simple echocardiographic predictor of procedural success to select patient for percutaneous suture-mediated patent fossa ovalis (PFO) closure.

BACKGROUND

Percutaneous suture-mediated PFO closure has been shown as a safe and advantageous alternative to device-based PFO closure, yet its overall success is slightly lower in unselected patients.

METHODS

Preprocedural transesophageal echocardiogram (TEE) of 302 patients (113 men, 45 ± 12 years) who underwent percutaneous suture-mediated PFO closure were reviewed.

RESULTS

At echocardiographic follow-up (3-6 months), residual right-to-left shunt (RLS) ≥2 was found in 60 (19.9%) patients. At multivariable analysis, only two anatomical variables measured at preprocedural TEE were found as independent predictors of residual RLS ≥ 2 at follow-up: PFO maximum width (odds ratio [OR] 1.89, 95% confidence interval [CI] 1.16-3.40, p = 0.02) and PFO minimal septa overlapping (OR 0.58, 95% CI 0.35-0.88, p = 0.02). An index based on the ratio of PFO maximum width to PFO minimum septal overlapping (W/SO) proved to be the most powerful predictor of RLS ≥ 2 at follow-up (OR 48.1, 95% CI 9.3-352.2, p < 0.01). The ROC curve for the W/SO ratio was found to have an AUC of 0.84 (95% CI 0.75-0.93) and a cut-off value of 0.61 yielding a sensitivity of 80% and specificity of 78% with a negative predictive value of 94%. A decision tree methodology's AUC was 0.75 (95% CI 0.67-0.83).

CONCLUSIONS

The results of this study indicate that the ratio between the maximum amplitude of the PFO and the minimum overlap of the septa is the best predictive index of a favorable result by using one stitch only.

A fully biodegradable polydioxanone occluder for ventricle septal defect closure

Ventricular septal defect (VSD) is one of the commonest congenital heart diseases (CHDs). Current occluders for VSD treatment are mainly made of nitinol, which has the risk of nickel allergy, persistent myocardial abrasion and fatal arrythmia. Herein, a fully biodegradable polydioxanone (PDO) occluder equipped with a shape line and poly-l-lactic acid PLLA membranes is developed for VSD closure without the addition of metal marker. PDO occluder showed great mechanical strength, fatigue resistance, geometry fitness, biocompatibility and degradability. In a rat subcutaneous implantation model, PDO filaments significantly alleviated inflammation response, mitigated fibrosis and promoted endothelialization compared with nitinol. The safety and efficacy of PDO occluder were confirmed in a canine VSD model with 3-year follow-up, demonstrating the biodegradable PDO occluder could not only effectively repair VSD, induce cardiac remodeling but also address the complications associated with metal occluders. Furthermore, a pilot clinical trial with five VSD patients indicated that all the occluders were successfully implanted under the guidance of echocardiography and no adverse events occurred during the 3-month follow-up. Collectively, the fully bioresorbable PDO occluder is safe and effective for clinical VSD closure and holds great promise for the treatment of structural CHDs.

Development of Innovative Biomaterials and Devices for the Treatment of Cardiovascular Diseases

Cardiovascular diseases have become the leading cause of death worldwide. The increasing burden of cardiovascular diseases has become a major public health problem and how to carry out efficient and reliable treatment of cardiovascular diseases has become an urgent global problem to be solved. Recently, implantable biomaterials and devices, especially minimally invasive interventional ones, such as vascular stents, artificial heart valves, bioprosthetic cardiac occluders, artificial graft cardiac patches, atrial shunts, and injectable hydrogels against heart failure, have become the most effective means in the treatment of cardiovascular diseases. Herein, an overview of the challenges and research frontier of innovative biomaterials and devices for the treatment of cardiovascular diseases is provided, and their future development directions are discussed.

A Novel Puncturable Atrial Septal Defect Occluder: The Results of Preclinical Experiment and First-in-Human Study

ReAces is a novel puncturable transcatheter atrial septal defect occluder. The device success rate was 100% (n = 14 of 14) in the animal experiment. Four swine successfully received puncture of the device 60 days after implantation of the device. The acute procedure success rate in the 10 patients was 100%. Transthoracic echocardiography examination showed that the devices were well positioned with no residual shunt, and the area of central portion of occluder was substantially thin. It is safe and effective to use ReAces for closure of secundum atrial septal defect, and puncture the atrial septum at the portion of the device is feasible.

Echocardiographic characteristics of transcatheter closure of patent foramen ovale with mallow biodegradable occluder: A single-center, phase III clinical study

Background

Transcatheter occlusion of patent foramen ovale (PFO) has become a recognized treatment option for high-risk PFO-related diseases. However, traditional metal occluders have some disadvantages, such as permanent retention in the body, abrasion of tissues, and obstruction of access to the left side of the heart for interventional procedures. With biodegradable occluders that release non-toxic degradation products and are absorbable by the body, the risk of long-term complications could be greatly reduced. The experimental results of using a PFO-degradable occluder in beagle dogs in early stages, independently developed by Shanghai Mallow Medical Instrument Co., Ltd., showed that the occluding umbrella disc network was degraded 6 months after occlusion. The occluder also showed good memory, biocompatibility, and mechanical properties.

Methods

As one of the multi-center research units, this prospective Phase III clinical trial study included 16 patients with PFO-related complications who were treated with a degradable occluder. The follow-up period lasted for 12 months to analyze the echocardiographic characteristics and procedural feasibility.

Results

The immediate success rate of the procedure was 100% with no serious complications. Postoperative color Doppler transthoracic echocardiography (TTE) and transesophageal echocardiography (TEE) at 12 months showed that one patient with atrial septal aneurysm (ASA) had a residual shunt at the edge of the occluder, and contrast transcranial Doppler (cTCD) showed that all patients were grade I or 0 right-to-left shunts (RLS), indicating that the occlusion success rate was 100%. The occluder gradually degraded after the procedure, particularly when the umbrella disc structure became vague, and the size of the occluder decreased significantly 6 months after occlusion.

Conclusions

PFO closure with a Mallow degradable occluder has a high plugging success rate, is safe and effective, and has no serious complications. However, for PFO closure with special anatomical features, further research with a larger sample size is required. TTE can dynamically, conveniently, and accurately observe the entire degradation process of the occluder.

Clinical Trial Registration

ChiCTR1900024036.

A Prospective, Single-Center, Phase I Clinical Trial to Evaluate the Value of Transesophageal Echocardiography in the Closure of Patent Foramen Ovale With a Novel Biodegradable Occluder

Objective

Traditional metal alloy occluders for the closure of patent foramen ovale (PFO) may be associated with some potential complications, and may restrict the trans-septal access to the left atrium for future treatment of left-sided heart disease. Increasing attention has been paid to novel biodegradable occluders (NBOs) to achieve PFO closure. We aimed to evaluate the role of transesophageal echocardiography (TEE) in the diagnostic and anatomical evaluation of PFO, as well as in the Post-procedural assessment after transcatheter closure with a NBO.

Methods

We conducted a prospective, single-center clinical study of 44 patients who were diagnosed with PFO by contrast transthoracic echocardiography (c-TTE) and TEE from June 2019 to June 2020. All patients underwent PFO occlusion with NBO under TTE guidance. Follow-up was performed at 2 days and 3 months after the procedure with TTE, and at 6 months and 1 year after the procedure with c-TTE, TTE, and TEE.

Results

Interventional treatment was successfully performed in all patients. The left and right sides of the occluder device disc were significantly reduced at 3, 6, and 12 months compared to 2 days after the procedure (all P &lt; 0.01), and decreased gradually. The thickness was significantly reduced at 12 months compared to the first three time points (all P &lt; 0.01). Thrombus was found on the surface of the occluder device in three patients (6.4%) at 3 and 6 months after occlusion. At 6 months after procedure, there were 3 (6.8%) cases of extensive residual right-to-left shunt (RLS), 2 (4.5%) cases of moderate shunt, and 7 (15.9%) cases of small shunts. One year after procedure, 2 (4.5%) cases had a extensive residual shunt, 6 (13.6%) cases of small shunts were confirmed to originate from pulmonary veins by TEE, and the PFO-RLS occlusion rate reached 95.5%.

Conclusion

This study demonstrates the feasibility, safety, and effectiveness of NBO for the closure of PFO in humans, with a high rate of complete shunt closure. Accurate TEE assessment of the PFO anatomy before closure with NBO is important to ensure that the procedure remains safe and effective. Furthermore, TEE plays a crucial role in the Post-procedure follow-up.

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.

Predictors of Residual Right-to-Left Shunt After Percutaneous Suture-Mediated Patent Fossa Ovalis Closure

OBJECTIVES

This study sought to assess patent fossa ovalis (PFO) anatomy by transesophageal echocardiography (TEE) in patients undergoing percutaneous suture-mediated PFO closure to identify predictors of post-procedural residual atrial right-to-left shunt (RLS).

BACKGROUND

Percutaneous suture-mediated PFO closure has been proven to be a safe and effective technique in most PFO patients.

METHODS

From June 2016 to October 2019, 247 consecutive patients underwent percutaneous suture-mediated PFO closure at our institution. Of them, 230 (46 ± 13 years of age, 146 women) had complete and technically evaluable pre-procedural TEE. The following parameters in short-axis view were assessed: presence and grade of spontaneous RLS, PFO length and width, presence of atrial septal aneurysm and its maximal bulge, and presence of an embryonic or fetal remnant (Chiari network or Eustachian valve).

RESULTS

At the first follow-up transthoracic echocardiography performed between 3 and 6 months from the closure procedure, a residual RLS ≥2 grade was found in 37 (16%) patients. Grade of pre-procedural spontaneous RLS (hazard ratio: 1.99; 95% confidence interval: 1.14 to 3.48; p = 0.016) shunt and PFO width (hazard ratio: 2.52; 95% confidence interval: 1.85 to 3.43; p < 0.001) were both found to be significantly associated with significant residual RLS at multivariable analysis. The presence of atrial septal aneurysm and its maximal bulge and of congenital remnants was not associated with significant residual RLS.

CONCLUSIONS

Percutaneous suture-mediated PFO closure is feasible in the majority of septal anatomies; however, PFO >5 mm in width and spontaneous large RLS are less likely to be closed with 1 stitch only.

Recent developments in next-generation occlusion devices

Transcatheter closure has been widely accepted as a highly effective way to treat abnormal blood flows and/or embolization of thrombus in the heart. It allows the closure of four types of congenital heart defects (CHDs) and stroke-associated left atrial appendage (LAA). The four types of CHDs include atrial septal defect (ASD), patent foramen ovale (PFO), patent ductus arteriosus (PDA), and ventricular septal defect (VSD). Advancements in the materials and configurations of occlusion devices have spurred the transition from open-heart surgery with high complexity and morbidity, or lifelong medication with a high risk of bleeding, to minimally invasive deployment. A variety of occlusion devices have been developed over the past few decades, particularly novel ones represented by biodegradable and 3D-printed occlusion devices, which are considered as next-generation alternatives to conventional Nitinol-based occlusion devices due to biodegradability, customization, and improved biocompatibility. The aim here is to comprehensively review the next-generation occlusion devices in terms of materials, configurations, manufacturing methods, deployment strategies, and (if available) experimental results or clinical data. The current challenges and the direction of future work are also proposed. STATEMENT OF SIGNIFICANCE: Implantation of occlusion devices has become a widely accepted and highly effective treatment for occluding abnormal blood/thrombus flow within the heart. Due to the serious complications such as erosion and displacement of conventional Nitinol-based occluders, next-generation occluders with reduced risk of complications and improved biocompatibility has emerged. Here, we comprehensively review the next-generation occluders developed for atrial septal defect (ASD), patent foramen ovale (PFO), patent ductus arteriosus (PDA), ventricular septal defect (VSD), and left atrial appendage (LAA), with special emphasis on biodegradable occluders. Besides, intelligent materials (e.g., automatically deployable shape memory polymers) and rapid customized manufacturing methods (3D/4D printing) for the fabrication of occluders are also introduced. Lastly, the directions of future work are highlighted.

Biodegradable polymeric occluder for closure of atrial septal defect with interventional treatment of cardiovascular disease

The next-generation closure device for interventional treatment of congenital heart disease is regarded to be biodegradable, yet the corresponding biomaterial technique is still challenging. Herein, we report the first fully biodegradable atrial septal defect (ASD) occluder finally coming into clinical use, which is made of biodegradable poly(l-lactic acid) (PLLA). We characterized the physico-chemical properties of PLLA fibers as well as the raw polymer and the operability of the as-fabricated occluders. Cell behaviors on material were observed, and in vivo fiber degradation and inflammatory responses were examined. ASD models in piglets were created, and 44 PLLA ASD occluders were implanted via catheter successfully. After 36 months, the PLLA ASD occluders almost degraded without any complications. The mechanical properties and thickness between newborn and normal atrial septum showed no significant difference. We further accomplished the first clinical implantation of the PLLA ASD occluder in a four-year boy, and the two-year follow-up up to date preliminarily indicated safety and feasibility of such new-generation fully biodegradable occluder made of synthetic polymers.

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.

Structural heart intervention for prevention of embolic and hemorrhagic stroke: The new field of neurocardiology

Cardiogenic stroke (CS), characteristic causes of which include atrial fibrillation (AF) and right-to-left shunting due to a patent foramen ovale (PFO), has a well-known tendency to be associated with a more extensive ischemic area. This may result in severe neurological damage, and require strict life-long antithrombotic therapy. However, the fact that some patients have problems complying with the requirement for extended oral antithrombotic treatment has motivated the development of alternative approaches for stroke prevention. Heart structures such as the left atrial appendage (LAA) and PFO are potential targets for stroke prevention by way of device implantation. Several large prospective randomized clinical trials have demonstrated efficacy and safety of devices dedicated to this purpose. Percutaneous LAA occlusion for patients with non-valvular AF resulted in similar embolic event rates but significantly reduced bleeding events than did therapy with warfarin. Furthermore, PFO closure significantly reduced the frequency of recurrent embolic stroke relative to oral antithrombotic treatment. Current unsolved problems remaining in the application of these two strategies can be identified as the lack of standardized regimens for post-procedural antithrombotic therapy, ambiguity of determining the indications therefore, and the problem of device-related thrombus, which need to be investigated in depth in future. Cost-benefit analysis in comparison with standard medication is also required for each instance. A heart-brain multidisciplinary team approach, mandated to start such structural heart interventions, will become the future standard unit of personnel for stroke management, which promises to usher in the new field of neurocardiology.

Long-Term Outcome After Transcatheter Atrial Septal Defect Closure in Adults: A Systematic Review and Meta-Analysis

AIMS

We performed a systematic review and meta-analysis of published studies to characterize the current literature and help determine the long-term outcomes after transcatheter ASD closure in adults.

METHODS AND RESULTS

Two investigators searched the manuscript databases for all eligible studies in accordance with the considered keywords. The pooled prevalence of each event according to the meta-analysis and considering the weight calculated for each study included 10.1% (for arrhythmia), 1.8% (for emboli), 2.3% (for stroke), 12.5% (for residual shunt), 1.8% (for erosion), and 2.5% (for death).

CONCLUSION

The present meta-analysis show high long-term successfulness of transcatheter ASD closure in adults.

Patent Foramen Ovale, the Role of Antiplatelet Therapy Alone or Anticoagulant Therapy Alone Versus Device Closure for Cryptogenic Stroke: A Review of the Literature and Current Recommendations

Cryptogenic stroke and its relation to the Patent Foramen Ovale (PFO) is a long-debated topic. Recent clinical trials have unequivocally established the relationship between cryptogenic strokes and paradoxical embolism across the PFO. This slit-like communication exists in everyone before birth, but most often closes shortly after birth. PFO may persist as a narrow channel of communication between the right and left atria in approximately 25-27% of adults. In this review, we examine the clinical relevance of the PFO with analysis of the latest trials evaluating catheter-based closure of PFO's for cryptogenic stroke. We also review the current evidence examining the use of antiplatelet medications versus anticoagulants for stroke prevention in those patients with PFO who do not qualify for closure per current guidelines.

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.

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.

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.

Interventional Cardiology for Congenital Heart Disease

Congenital heart interventions are now replacing surgical palliation and correction in an evolving number of congenital heart defects. Right ventricular outflow tract and ductus arteriosus stenting have demonstrated favorable outcomes compared to surgical systemic to pulmonary artery shunting, and it is likely surgical pulmonary valve replacement will become an uncommon procedure within the next decade, mirroring current practices in the treatment of atrial septal defects. Challenges remain, including the lack of device design focused on smaller infants and the inevitable consequences of somatic growth. Increasing parental and physician expectancy has inevitably lead to higher risk interventions on smaller infants and appreciation of the consequences of these interventions on departmental outcome data needs to be considered. Registry data evaluating congenital heart interventions remain less robust than surgical registries, leading to a lack of insight into the longer-term consequences of our interventions. Increasing collaboration with surgical colleagues has not been met with necessary development of dedicated equipment for hybrid interventions aimed at minimizing the longer-term consequences of scar to the heart. Therefore, great challenges remain to ensure children and adults with congenital heart disease continue to benefit from an exponential growth in minimally invasive interventions and technology. This can only be achieved through a concerted collaborative approach from physicians, industry, academia and regulatory bodies supporting great innovators to continue the philosophy of thinking beyond the limits that has been the foundation of our specialty for the past 50 years.

AMPLATZER versus Figulla occluder for transcatheter patent foramen ovale closure

AIMS

The aim of this observational study was to compare acute and 12-month results of percutaneous closure of patent foramen ovale (PFO) with two occluder devices.

METHODS AND RESULTS

Between June 2007 and October 2014, 406 consecutive patients (48.1±13.3 years, 243 women) underwent percutaneous PFO closure with either the AMPLATZER (n=179) or the Figulla (n=227) device after a stroke or a transient ischaemic attack ascribed to the PFO. A right-to-left shunt grade >1 was previously detected in all patients and atrial septal aneurysm was present in 111 (27.5%) patients. Patients were followed up with a contrast transthoracic echocardiogram and clinically at 24 hours, six months, and 12 months after the procedure. A high procedural success was observed in both groups. Despite a trend towards a higher incidence of acute residual shunt immediately after device deployment among Figulla occluder patients, a residual grade ≥2 right-to-left shunt was observed in 4.5% of patients, independently of the device used for PFO closure. The only difference reported after Figulla device implantation was a lower rate of supraventricular arrhythmias (9% vs. 17%, p=0.02).

CONCLUSIONS

According to this two-centre study, PFO closure appears safe and effective with the Figulla occluder as well as with the AMPLATZER device.

Current Status and Future Potential of Transcatheter Interventions in Congenital Heart Disease

Percutaneous therapies for congenital heart disease have evolved rapidly in the past 3 decades. This has occurred despite limited investment from industry and support from regulatory bodies resulting in a lack of specific device development. Indeed, many devices remain off-label with a best-fit approach often required, spurning an innovative culture within the subspecialty, which had arguably laid the foundation for many of the current and evolving structural heart interventions. Challenges remain, not least encouraging device design focused on smaller infants and the inevitable consequences of somatic growth. Data collection tools are emerging but remain behind adult cardiology and cardiac surgery and leading to partial blindness as to the longer-term consequences of our interventions. Tail coating on the back of developments in other fields of adult intervention will soon fail to meet the expanding needs for more precise interventions and biological materials. Increasing collaboration with surgical colleagues will require development of dedicated equipment for hybrid interventions aimed at minimizing the longer-term consequences of scar to the heart. Therefore, great challenges remain to ensure that children and adults with congenital heart disease continue to benefit from an exponential growth in minimally invasive interventions and technology. This can only be achieved through a concerted collaborative approach from physicians, industry, academia, and regulatory bodies supporting great innovators to continue the philosophy of thinking beyond the limits that has been the foundation of our specialty for the past 50 years.

A Novel-Design Poly-L-Lactic Acid Biodegradable Device for Closure of Atrial Septal Defect: Long-Term Results in Swine

Objectives: The aim of this study is to evaluate the long-term effectiveness and safety of a self-expandable, double-disk biodegradable device made of poly-L-lactic acid (PLLA) for closure of atrial septal defects (ASDs) in swine. Methods: ASDs were created by transseptal needle puncture followed by balloon dilatation in 20 piglets. The experimental group comprised 18 animals, while the remaining 2 animals were used as controls. Effectiveness and safety were evaluated by rectal temperature, leukocyte count, chest radiography, electrocardiogram, transthoracic echocardiography (TTE), intracardiac echocardiography (ICE), and histologic studies. Animals were followed up at 1, 3, 6, and 12 months. Results: An ASD model was successfully created in 19 animals; 1 piglet died during the procedure. The ASD diameters that were created ranged from 5 to 6.4 mm. Devices were successfully implanted in 17 animals. No animal died during the follow-up studies. Rectal temperatures and electrocardiograms were normal at follow-up, while leukocyte counts transiently increased from 1 to 6 months. Radiography, TTE, ICE, and macroscopic studies demonstrated that PLLA occluders were positioned well, with no shifting, mural thrombus formation, or atrioventricular valve insufficiency. Histologic evaluations showed that PLLA devices were partially degraded in the follow-up study. Conclusions: ASD closure with the novel PLLA biodegradable device is safe and effective. Longer-term studies are needed to evaluate long-term biodegradability.

Historical developments of atrial septal defect closure devices: what we learn from the past

INTRODUCTION

Since King and Mills' pioneering work in percutaneous closure devices of secundum atrial septal defects (ASD) four decades ago, developments in device shape, material and implantation technique led to adoption of percutaneous ASD closure as current treatment of choice. Not only was the feasibility of such a percutaneous procedure tested altogether, but pursuing the ideal device in terms of safety and efficacy became priority.

AREAS COVERED

In this review we present the historical development of ASD devices in design, material and technique with clinical data, and provide the future perspectives in percutaneous ASD closures.

EXPERT OPINION

An 'ideal device' requires complete defect closure with negligible risk of complications using a safe, straightforward delivery technique with repositioning and retrieving properties. Some of the devices currently at hand come close to fulfilling these criteria, however none seem to provide those prerequisites completely. By understanding how challenges in device development were overcome in the past, new insights into future improvements are given.

Secundum atrial septal defect in adults: a practical review and recent developments

Secundum atrial septal defect (ASDII) is a common congenital heart defect that causes shunting of blood between the systemic and pulmonary circulations. Patients with an isolated ASDII often remain asymptomatic during childhood and adolescence. If the defect remains untreated, however, the rates of exercise intolerance, supraventricular arrhythmias, right ventricular dysfunction and pulmonary arterial hypertension (PAH) increase with patient age, and life expectancy is reduced. Transcatheter and surgical techniques both provide valid options for ASDII closure, the former being the preferred method. With the exception of those with severe and irreversible PAH, closure is beneficial to, and thus indicated in all patients with significant shunts, regardless of age and symptoms. The symptomatic and survival benefits conferred by defect closure are inversely related to patient age and the presence of PAH, supporting timely closure after diagnosis. In this paper we review the management of adult patients with an isolated ASDII, with a focus on aspects of importance to the decision regarding defect closure and medical follow-up.

Biomaterials and design in occlusion devices for cardiac defects: a review

This review examines the biomaterials used in occlusion devices for cardiac defects, and how the choice of these materials is dictated by design. Specifically, the devices used in three major applications, the atrial septal defect, the ventricular septal defect and the patent ductus arteriosus, are examined critically. A number of different devices are available, with varied performance in deployment and sealing. There is no device in any of the three categories that satisfies fully the range of requirements, and all have associated complications. The type and rate of complications are different among different devices. The short-term (immediate) complications are addressed by immediate retrieval. For longer-term complications, most of which can be fatal, currently only surgical retrieval and replacement are possible. Most of these longer-term complications can be alleviated by the use of fully degradable devices, which will eliminate concerns regarding the use of metals inside the heart, and if fully endothelialized, also minimize migration concerns. On the other hand, the lower moduli of currently available biodegradable materials need to be augmented. Improvements in the stiffness required for deployment can be accomplished with the use of fillers, nano- or micro-sized, and an example of this are radiopaque fillers.

Transcatheter interatrial septal defect closure in a large cohort: midterm follow-up results

OBJECTIVES

We evaluated immediate and midterm results of transcatheter closure of atrial septal defects (ASDs) and patent foramen ovale (PFO) using various closure devices.

MATERIALS AND METHODS

The study included four hundred fourteen patients (one hundred eighty-two men, two hundred thirty-two women; mean age 39 ± 12.3 years; range 17-67 years) who underwent transcatheter closure of secundum ASD (n = 193) or PFO (n = 221). All the patients were evaluated by transthoracic echocardiography and transesophageal echocardiography before the procedure. Transcatheter closure was performed by using Amplatzer (n = 184), Occlutech Figulla (n = 209), or BioSTAR (n = 21) devices. Closure of ASDs was performed under general anesthesia with transesophageal echocardiography guidance, and closure of PFOs was performed under local anesthesia with transthoracic echocardiography guidance. Follow-up controls were at 1, 6, and 12 months and annually thereafter. The median follow-up periods of ASD and PFO patients were 43 and 30 months.

RESULTS

The mean device size was 19.3 ± 6.2 mm for ASD patients and 24.6 ± 2.6 mm for PFO patients. The mean procedural and fluoroscopy times were 22.3 ± 4.7 and 4.1 ± 1.9 minutes for ASD closure and 12.4 ± 3.2 and 3.1 ± 1.2 minutes for PFO closure, respectively. Procedural device embolization occurred in only two patients (0.48%). During follow-up, recurrent embolic events occurred in four patients (1.8%) after PFO closure, and no residual shunts were seen after ASD closure. Device thrombosis developed in two ASD patients during the procedure and in one PFO patient at 12th month of the follow-up (0.72%).

CONCLUSION

Transcatheter closure of PFOs and secundum-type ASDs using the Amplatzer, Occlutech Figulla, and BioSTAR devices is an efficacious and safe therapeutic option.

Patent foramen ovale in severe obstructive sleep apnea: clinical features and effects of closure

BACKGROUND

Patent foramen ovale (PFO) may contribute to nocturnal desaturation in patients with obstructive sleep apnea (OSA), and the effect of PFO closure in OSA is unknown. Our study tested the hypotheses that: (1) patients with severe OSA have a higher prevalence of PFO compared with healthy control subjects, (2) patients with severe OSA with clinically significant PFO experience more nocturnal desaturation than those without, and (3) PFO closure reduces nocturnal desaturation.

METHODS

Patients with severe OSA and healthy control subjects underwent contrast transthoracic echocardiography and transcranial Doppler to detect PFO and determine shunt size. A subgroup of patients with OSA with large shunts underwent percutaneous PFO closure. Polysomnography was performed at baseline and 1, 6, and 12 months postclosure.

RESULTS

One hundred patients with OSA (mean [SD] age, 52 [10] years; apnea-hypopnea index [AHI], 54 [18] events/h) and 50 control subjects (age, 52 [11] years; AHI, 2 [2] events/h) were studied. PFO prevalence was 43% in patients with OSA and 30% in control subjects ( P = .16). Large shunts were detected in 18% of patients with OSA and 6% of control subjects ( P = .049). Patients with OSA with clinically significant shunts had higher oxygen-desaturation index (ODI)/AHI ratios than patients without (ratio, 1.05 [0.27] vs 0.86 [0.26], P = .004). Six patients with OSA underwent PFO closure, which was not associated with a reduction in ODI (baseline, 48 [18]; 12 months, 51 [19] events/h; P = .92) or percentage of the night with arterial oxygen saturation , 90% (baseline, 23% [16%]; 12 months, 20% [22%]; P = .35).

CONCLUSIONS

Patients with severe OSA have a higher prevalence of PFO with large shunts compared with control subjects. The ODI/AHI ratio is increased in patients with OSA with clinically significant shunts. PFO closure does not reduce nocturnal desaturation.

Outcomes After Transcatheter ASD Closure

Ostium secundum-type atrial septal defect closure has evolved from a surgical procedure requiring cardiopulmonary bypass to a percutaneous, catheter-based procedure usually requiring only an overnight hospital stay. The overall safety and effectiveness has compared favorably with surgical repair. Although rare, complications have been described, including erosion, device embolization, or malfunction and arrhythmias. The overall long-term clinical outcomes have been excellent: good quality of life, functional class improvement, and ventricular remodeling have been the rule after the procedure. It is mandatory to recommend indefinite follow-up of patients undergoing this procedure for potential long-term complications.

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.

Transcatheter closure of multiple interatrial communications

OBJECTIVES

We sought to examine acute and midterm results of closure of multiple interatrial communications with staged device deployment and to review the relevant literature.

BACKGROUND

Information about percutaneous methods of closure for multiple defects is limited.

METHODS

We treated 148 patients with multiple defects. Of these, 88 had a relevant left to right shunt ("LRS"), 52 had a presumed paradoxical embolism ("PPE"), five had both (LRS and PPE), and one patient, respectively, had migraine, decompression sickness, and a right to left shunt. After implantation of the first device, closure of additional septal defects was attempted only if indicated clinically.

RESULTS

Ninety-four patients received a single device and 53 more than one. In four patients, surgical defect closure followed. At the end of follow-up (FU; mean 4.5 ± 3.4 years), complete closure of all defects occurred in 67.6% (62.1% for LRS, 76.5% for PPE). Clinical success (small or trivial residual shunt) was achieved in 86.9% (83.9% for LRS, 90.2% for PPE). Complications included pericardial effusions in 2.7%, recurrent thromboembolic events in 4.8%, and new onset of atrial fibrillation in 10.1%. In a significant number of patients with multiple defects, after single device implantation, the likelihood of complete closure increased with FU time (26% complete closure at 1 month vs. 78% at 24 months).

CONCLUSION

Percutaneous closure of multiple interatrial communications is feasible and safe. Importantly, many residual defects close without further intervention at FU. Therefore, staged device delivery is an alternative to simultaneous device implantation, possibly requiring fewer and smaller second devices.

Double BioDisk: a new bioprosthetic device for transcatheter closure of atrial septal defects - a feasibility study in adult sheep

BACKGROUND

To evaluate the long-term effectiveness and safety of a new Double BioDisk (DBD) device for closure of atrial septal defect (ASD). MATERIALS AND METHODS.: ASD was created with transeptal needle (TS) followed by balloon dilatation in 12 sheep weighing 40.1 to 64 kg (mean 55.2 ± 7.1). The ASD diameters were measured after creation and two weeks later before DBD implantation. The DBDs consists of two nitinol rings 18 to 28 mm in diameter connected with small cannulas and covered with a porcine small intestinal submucosa (SIS). They were implanted via a 10 Fr sheath. DBD effectiveness was evaluated by angiocardiography and by intra-cardiac echogram (ICE) with Doppler studies. Two animals were acute, two were followed for 6 weeks, three for 3 months, three for 6 months and two for 12 months.

RESULTS

TS punctures were successful in 10 sheep. In two sheep ASD was created by existing PFO dilation. The ASD size ranged from 13-15 mm (mean 14.1± 0.73 mm) after initial balloon dilation and from 9-13 mm (mean 10.06 ± 1.37 mm) after two weeks. In all animals none of the successfully implanted DBDs spontaneously embolized on release or on follow up. ICE demonstrated no shunting around the DBDs during follows ups. Macroscopic and histologic evaluation of the 6, 12, 24 and 52 weeks animals showed that DBDs were well incorporated in the atrial septum with complete shunt closure. The SIS showed progressive remodeling with the host cells, including endothelization of the DBD devices.

CONCLUSIONS

ASD closure with the Double BioDisk is safe and effective in adult sheep.