Stable Interatrial Communication Combining Balloon Atrial Septostomy and Radiofrequency Catheter Ablation

Is combined use of radiofrequency ablation and balloon dilation the future of interatrial communications?

INTRODUCTION

Personalized and stable interatrial communication is an important palliative therapy for patients with heart failure. However, this remains a technically challenging task.

AREAS COVERED

In the past decades, substantial advancements in atrial septostomy for the creation of controllable and durable interatrial communication have been made, and numerous novel devices and techniques are in various stages of development. In this review, we discuss the evolving indications for atrial septostomy, current approaches with or without device implantation, and indicators for optimal interatrial communication. The combined use of radiofrequency ablation and balloon dilation (CURB) is an individualized management approach based on underlying hemodynamics, which demonstrates unique advantages in creating a sufficient interatrial communication with satisfactory stability. The advantages and disadvantages of this implant-free procedure are analyzed and its clinical prospects are assessed.

EXPERT OPINION

With ready availability, high safety, and efficacy, CURB is a promising procedure for creating personalized and stable interatrial communication without device implantation. Further research is required to simplify the procedure, screen optimal reference parameters for personalized therapy, and evaluate the long-term outcome in a large population of patients.

Intracardiac echocardiography Chinese expert consensus

In recent years, percutaneous catheter interventions have continuously evolved, becoming an essential strategy for interventional diagnosis and treatment of many structural heart diseases and arrhythmias. Along with the increasing complexity of cardiac interventions comes ever more complex demands for intraoperative imaging. Intracardiac echocardiography (ICE) is well-suited for these requirements with real-time imaging, real-time monitoring for intraoperative complications, and a well-tolerated procedure. As a result, ICE is increasingly used many types of cardiac interventions. Given the lack of relevant guidelines at home and abroad and to promote and standardize the clinical applications of ICE, the members of this panel extensively evaluated relevant research findings, and they developed this consensus document after discussions and correlation with front-line clinical work experience, aiming to provide guidance for clinicians and to further improve interventional cardiovascular diagnosis and treatment procedures.

First in-human modified atrial septostomy combining radiofrequency ablation and balloon dilation

OBJECTIVE

Preclinical research suggests that the combined use of radiofrequency ablation and balloon dilation (CURB) could create stable interatrial communications without device implantation. This study examined the first in-human use of CURB for modified atrial septostomy in patients with severe pulmonary arterial hypertension (PAH).

METHODS

Between July 2018 and October 2021, CURB was performed in 19 patients with severe PAH (age: 31.5±9.1 years; mean pulmonary artery pressure: 73 mm Hg (IQR: 66-92); pulmonary vascular resistance: 18.7 Wood units (IQR: 17.8-23.3)). Under guidance of intracardiac echocardiography and three-dimensional location system, (1) fossae ovalis was reconstructed and ablated point-by-point with radiofrequency; (2) then graded balloon dilation was performed after transseptal puncture and the optimal size was determined according to the level of arterial oxygen saturation (SatO₂); (3) radiofrequency ablation was repeated around the rims of the created fenestration. The interatrial fenestrations were followed-up serially.

RESULTS

After CURB, the immediate fenestration size was 4.4 mm (IQR: 4.1-5.1) with intracardiac echocardiography, systolic aortic pressure increased by 10.2±6.9 mm Hg, cardiac index increased by 0.7±0.3 L/min/m² and room-air resting SatO2 decreased by 6.2±1.9% (p<0.001). One patient experienced increased pericardiac effusion postoperatively; the others had no complications. On follow-up (median: 15.5 months), all interatrial communications were patent with stable size (intraclass correlation coefficient=0.96, 95%CI:0.89 to 0.99). The WHO functional class increased by 1 (IQR: 1-2) (p<0.001) with improvement of exercise capacity (+159.5 m, P<0.001).

CONCLUSION

The interatrial communications created with CURB in patients with severe PAH were stable and the mid-term outcomes were satisfactory.

TRIAL REGISTRATION NUMBER

NCT03554330.

The RAISE Trial: A Novel Device and First-in-Man Trial

BACKGROUND

Currently, standard medical therapies have limited effects on heart failure with preserved ejection fraction (HFpEF), which impacts on the life quality and survival of patients. This study aimed to evaluate the safety and efficacy of the percutaneous radiofrequency ablation-based interatrial shunting for HFpEF with a novel atrial septostomy device.

METHODS

A preclinical study in 11 normal domestic pigs and the first-in-man study in 10 patients with HFpEF were performed. The major safety events and interatrial shunt performance were evaluated at baseline, 1 month, 3 months, and 6 months post-procedure in both animals and human patients. The clinical functional status was also assessed in the first-in-man study.

RESULTS

Percutaneous radiofrequency ablation-based interatrial shunting therapy was performed successfully both in animals and patients. In the animal study, a left-to-right interatrial shunt was created with a mean defect size of 5.5±2.2 mm without procedure-related safety events. Seven pigs showed the continuous shunting with a mean defect size of 4.1±1.5 mm at 6 months. In the first-in-man study, a median interatrial defect diameter of 5.0 (4.0-6.0) mm was measured immediately. No major safety events including death and thromboembolism were observed. The continuous shunting with the defect size of 4.0 (3.0-4.0) mm could still be observed in 7 patients at 6 months. The clinical status was significantly improved with NT-proBNP (N-terminal pro-B-type natriuretic peptide) reduced by 2149 pg/mL ([95% CI, 204-3301] P=0.028), with 6-minute walk distance increased by 88 m ([95% CI, 50-249] P=0.008) and with New York Heart Association class improved in 8 patients at 6 months.

CONCLUSIONS

The present results showed that percutaneous radiofrequency ablation-based interatrial shunting was a safe and potentially effective therapy for HFpEF, providing a nonpharmacological and nonimplanted option for HFpEF management.

REGISTRATION

URL: https://www.chictr.org.cn; Unique identifier: ChiCTR1900027664.

Modern advances regarding interatrial communication in congenital heart defects

BACKGROUND

The interatrial communication, one of the most frequent congenital heart defects, represents an important intracardiac shunt between systemic and pulmonary circulations. Direction and magnitude of the interatrial shunting depends upon several features, including defect size, shape and location, pressure difference between right and left atrium, and difference in right and left ventricular compliance.

METHODS

In this review article, the presence or absence of interatrial communication, and its role, have been analyzed, as they can have a critical impact on the cardiovascular physiopathology, and the interatrial communication can prove to be either clinically harmful, useful or indispensable. Accordingly, the utility and role of the interatrial communication in modern congenital, pediatric and adult, disease has evolved, with modification of the indications to close, maintain patency, or create an interatrial communication.

RESULTS

The interatrial communication and shunting can be manipulated to maximize the oxygen delivery to the tissues, accordingly with the underlying congenital heart defect. While not always relevant to patients with bi-ventricular circulations, this becomes extremely important in children and adults with complex congenital heart defects.

CONCLUSIONS

With improving long-term survival for the vast majority of congenital heart patients, an advanced understanding of the role and utility of the interatrial communication, and of all the possibilities of its manipulation, is essential to improve the patient outcomes.

Transfemoral transcatheter puncture of interventricular septum in a swine model: A novel transfemoral-venous access to left ventricle with the assistance of arterio-venous circuit

OBJECTIVE

Via subclavian/jugular vein, successful puncture of interventricular septum (IVS) has been achieved transvenously. However, the approach was limited by acute entry-angle. The study was conducted to investigate a novel transcatheter puncture of IVS via femoral access and transfemoral-venous access to left ventricle (LV) through IVS.

METHODS

Via femoral artery, transcatheter puncture of mid-IVS was performed with a custom-made nickel-titanium needle and 6F-sheath in 16 healthy mini-swine. Then femoral arterio-venous circuit was established through IVS. After pre-dilation of IVS, a 20F-sheath was introduced into LV transvenously over-the-guidewire in 15 swine. Furthermore, transfemoral-venous TAVR was attempted with the approach in another swine. IVS was evaluated postoperatively and was further confirmed pathologically 2 months later.

RESULTS

All transcatheter puncture of IVS was performed successfully in LV and the mid-IVS thickness was 7.67 ± 0.98 mm. In all swine, femoral arterio-venous circuit was established via IVS, and a 20F-sheath was introduced into LV and aorta transfemoral-venously (entry-angle: 145.3 ± 12.2° in front view). After the procedure, there was one swine with moderate tricuspid-regurgitation and five swine with mild residual-shunt (2.6 ± 0.7 mm). Two months later, residual-shunt was still detected in three swine and the communication was confirmed pathologically. In other swine, no defect occurred and replacement-scar was identified along puncture-tract. In the swine underwent transfemoral-venous TAVR, prosthetic valve was deployed successfully with good function.

CONCLUSIONS

Transfemoral transcatheter puncture of IVS is feasible and safe in a swine model, and large sheath can be introduced into LV transfemoral-venously using the novel access with the aid of vessel circuit.

Interventional Treatment of Cardiac Emergencies in Children with Congenital Heart Diseases

Cardiac emergencies in children represent an extremely important issue in medical practice. In general, interventional treatment could be optional in many situations, however it can be indicated in emergency conditions. There are many diseases at pediatric age that can benefit from interventional treatment, thus reducing the surgical risks and subsequent complications. Balloon atrioseptostomy, patent ductus arteriosus (PDA) closure, percutaneous or hybrid closure of a ventricular septal defect, pulmonary or aortic valvuloplasty, balloon angioplasty for aortic coarctation, implantation of a stent for coarctation of the aorta, for severe stenosis of the infundibulum of the right ventricle, or for PDA correction are among the procedures that can be performed in emergency situations. This review aims to present the current state of the art in the field of pediatric interventional cardiology.