Atrial septostomy: stationary angioplasty balloon technique--experimental work and preliminary clinical applications

Static balloon atrial septostomy in Japan in shortage of standard balloon septostomy catheter

BACKGROUND

The supply of Rashkind balloon atrial septostomy (BAS) catheters (Medtronic, Minneapolis, MN, USA) has suddenly been discontinued in the world due to its recall. Consequently, Japan fell into a critical shortage of standard BAS catheters. Although the use of static BAS is off-label in Japan, its importance is increasing in such a situation. A nationwide survey of static BAS is needed in such a critical period.

METHODS

A questionnaire survey was conducted among centers in Japan regarding BAS performed between October 1, 2020, and December 15, 2020, while the supply of Rashkind BAS catheter was discontinued.

RESULTS

We received answers from 70 of the 90 centers, for a response rate of 78%. In this survey, 25 patients who underwent static BAS were enrolled, and a total of 47 BAS procedures were performed. Median age and weight at static BAS were 10 days of life and 3001 g, respectively. The most common diagnosis was transposition of the great arteries without pulmonary stenosis and hypoplastic left heart syndrome and its variants, with 8 cases each. The most frequently used balloon diameter was 10 mm (13 balloons), followed by 12 mm (10 balloons), and 3 cases required double-balloon techniques. The 3-point scale of the efficacy of static BAS rated by physicians were 10 excellent, 15 good, and 0 poor, respectively. Complications included cardiac tamponade during the procedure in 1 patient and the need for Rashkind BAS later in 2 patients. Comparing the share of static BAS in all transcatheter atrial septostomy, its share in the current survey (28/53) is significantly higher compared to the annual registry data in 2018 (86/304) (p < 0.01).

CONCLUSIONS

This survey shows that static BAS is widely performed in Japan and is effective and safe. Static BAS cases have increased significantly due to a shortage of standard BAS catheters.

Left atrial decompression as a palliative minimally invasive treatment for congestive heart failure caused by myxomatous mitral valve disease in dogs: 17 cases (2018-2019)

OBJECTIVE

To determine whether left atrial decompression (LAD) would reduce left atrial pressure (LAP) in dogs with advanced myxomatous mitral valve disease (MMVD) and left-sided congestive heart failure (CHF) and to describe the LAD procedure and hemodynamic alterations and complications.

ANIMALS

17 dogs with advanced MMVD and left-sided CHF that underwent LAD.

PROCEDURES

The medical record database was retrospectively reviewed for all LAD procedures attempted in dogs with MMVD and left-sided CHF between October 2018 and June 2019. Data were collected regarding signalment (age, breed, weight, and sex), clinical signs, treatment, physical examination findings, and diagnostic testing before and after LAD. Procedural data were also collected including approach, technique, hemodynamic data, complications, and outcome.

RESULTS

18 LAD procedures performed in 17 patients were identified. Dogs ranged in age from 7.5 to 16 years old (median, 11 years) and ranged in body weight from 2.9 to 11.6 kg (6.4 to 25.5 lb) with a median body weight of 7.0 kg (15.4 lb). Minimally invasive creation of an atrial septal defect for the purpose of LAD was successful in all dogs without any intraoperative deaths. Before LAD, mean LAP was elevated and ranged from 8 to 32 mm Hg with a median value of 14 mm Hg (reference value, < 10 mm Hg). Following LAD, there was a significant decrease in mean LAP (median decrease of 6 mm Hg [range, 1 to 15 mm Hg]). Survival time following LAD ranged from 0 to 478 days (median, 195 days).

CONCLUSIONS AND CLINICAL RELEVANCE

For dogs with advanced MMVD and left-sided CHF, LAD resulted in an immediate and substantial reduction in LAP.

Graded balloon atrial septostomy for palliation of congenital pulmonary hypertension in a dog: A case report

CASE DESCRIPTION

A 6-month-old intact female Maltese dog was presented for acute onset of syncope.

CLINICAL FINDINGS

The dog was presented for collapse upon excitement and exercise. It collapsed at discharge and suffered cardiopulmonary arrest. Echocardiography after resuscitation indicated severe pulmonary hypertension without evidence of intracardiac or extracardiac shunting. A presumptive diagnosis of congenital pulmonary hypertension was made.

TREATMENT AND OUTCOME

Initial treatment with sildenafil was effective at relieving syncope, but the extent of pulmonary hypertension as determined by serial echocardiography was unchanged. Graded balloon atrial septostomy was performed as a palliative procedure. Follow-up echocardiography identified a patent interatrial communication with bidirectional shunting. The dog remained asymptomatic 18 months after treatment.

CLINICAL RELEVANCE

To the best of our knowledge, this study is the first report in the veterinary literature of graded balloon atrial septostomy performed for therapeutic purposes. Further studies are required to determine if this palliative procedure is a beneficial treatment option for dogs with congenital or severe refractory pulmonary hypertension.

Left atrial decompression through unidirectional left-to-right interatrial shunt for the treatment of left heart failure: first-in-man experience with the V-Wave device

AIMS

Elevated filling pressures of the left atrium (LA) are associated with poorer outcomes in patients with chronic heart failure. The V-Wave is a new percutaneously implanted device intended to decrease the LA pressure by the shunting of blood from the LA to the right atrium. This report describes the first-in-man experience with the V-Wave device.

METHODS AND RESULTS

A 70-year-old man with a history of heart failure of ischaemic origin, left ventricular dysfunction (LVEF: 35%, pulmonary wedge: 19 mmHg), no right heart dysfunction, NYHA Class III and orthopnoea despite optimal treatment, was accepted for V-Wave device implantation. The device consists of an ePTFE encapsulated nitinol frame that is implanted at the level of the interatrial septum and contains a trileaflet pericardium tissue valve sutured inside which allows a unidirectional LA to right atrium shunt. The procedure was performed through a transfemoral venous approach under fluoroscopic and TEE guidance. The device was successfully implanted and the patient was discharged 24 hours after the procedure with no complications. At three-month follow-up a left-to-right shunt through the device was confirmed by TEE. The patient was in NYHA Class II, without orthopnoea, the Kansas City Cardiomyopathy index was 77.6 (from 39.1 at baseline) and NT-proBNP was 322 ng/mL (from 502 ng/mL at baseline). The QP/QS was 1.17 and the pulmonary wedge was 8 mmHg, with no changes in pulmonary pressure or right ventricular function.

CONCLUSIONS

Left atrial decompression through a unidirectional left-to-right interatrial shunt represents a new concept for the treatment of patients with left ventricular failure. The present report shows the feasibility of applying this new therapy with the successful and uneventful implantation of the V-Wave device, which was associated with significant improvement in functional, quality of life and haemodynamic parameters at 90 days.

Morphology of interatrial defects created by interventional techniques in a neonatal animal model

Pathological details are lacking of various techniques used for interatrial defect (IAD) creation in lesions requiring mixing or with left atrial hypertension. Therefore, the morphology of the IAD created by different interventional techniques is described. The atrial septa of ten euthanized piglets (seven at <3 days and three at 2 weeks of age) were surgically exposed. In pigs of both ages, a needle-created communication was dilated with angioplasty, cutting, and cryoplasty balloons. A stent was also implanted in a newborn pig. By way of a patent foramen ovale (PFO) in newborns, angioplasty and septostomy balloons and a stent created IADs. The morphology of the IAD was directly imaged and the size measured. Newborn piglets had noticeably thinner atrial septa, and a PFO was still present. Static balloon dilation created a circular IAD equivalent to the balloon diameter (3 and 6 mm) in both the created defects of pigs of both ages and the neonatal PFO. A 3-mm cutting balloon (CB) produced a 2-mm triangular IAD (corresponding to atherotomes) in pigs of both ages. Premounted stents, by way of a created defect or PFO, led to circular IADs equivalent to balloon diameter. The 3-mm cryoplasty balloon created a large 5 × 4-mm IAD in the newborn pig; however, the IAD measured only 2 × 1-mm at 2 weeks. By way of a neonatal PFO, a septostomy balloon (inflated to 2 cc) created a 3-mm circular IAD. In neonatal piglet hearts, static balloon angioplasty, CBs, and stents created a predictable IAD. Cryoplasty balloons created highly variable defects.

New transcatheter techniques for creation or enlargement of atrial septal defects in infants with complex congenital heart disease

OBJECTIVES

To describe a series of 8 consecutive infants (5 with transposition of the great arteries [TGA] and 3 with hypoplastic left heart syndrome [HLHS]) who underwent nonconventional septostomy techniques.

BACKGROUND

For some complex congenital heart defects, an unrestrictive atrial septal defect (ASD) is essential to achieve an adequate cardiac output and/or systemic saturation. In some scenarios, the use of conventional septostomy techniques may be technically difficult, hazardous, and/or ineffective.

METHODS

Use of transhepatic approach, cutting balloons, and radiofrequency perforation with stenting of the atrial septum.

RESULTS

The size of the ASD and the oxygen saturation increased in all patients with no major complications. In those with TGA, the ASDs were considered to be of good size at the arterial switch operation. Two of the 3 patients with hybrid palliation for HLHS have developed some degree of obstruction within the interatrial stent over 2-3 months. At surgery, the stents were found to be secured within the septum with one showing significant fibrous ingrowth after uneventful removal. The other had some nonobstructive ingrowth.

CONCLUSIONS

Creation or enlargement of ASDs in infants using new nonconventional transcatheter techniques is feasible, safe, and effective, at least in the short-to-mid-term follow-up. Infants with TGA seem to benefit the most because the procedure results in satisfactory clinical stability for subsequent early surgical intervention. In infants with HLHS palliated by a hybrid approach, stent implantation to the atrial septum seems to buy enough time to bring them to the phase II safely despite progressive in-stent obstruction.

Balloon Atrial Septostomy Is Associated With Preoperative Stroke in Neonates With Transposition of the Great Arteries

BACKGROUND

Preoperative brain injury is common in neonates with transposition of the great arteries (TGA). The objective of this study is to determine risk factors for preoperative brain injury in neonates with TGA.

METHODS AND RESULTS

Twenty-nine term neonates with TGA were studied with MRI before cardiac surgery in a prospective cohort study. Twelve patients (41%) had brain injury on preoperative MRI, and all injuries were focal or multifocal. None of the patients had birth asphyxia. Nineteen patients (66%) required preoperative balloon atrial septostomy (BAS). All patients with brain injury had BAS (12 of 19; risk difference, 63%; 95% confidence interval, 41 to 85; P=0.001). As expected on the basis of the need for BAS, these neonates had lower systemic arterial hemoglobin saturation (Sao2) (P=0.05). The risk of injury was not modified by the cannulation site for septostomy (umbilical versus femoral, P=0.8) or by the presence of a central venous catheter (P=0.4).

CONCLUSIONS

BAS is a major identifiable risk factor for preoperative focal brain injury in neonates with TGA. Imaging characteristics of identified brain injuries were consistent with embolism; however, the mechanism is more complex than site of vascular access for BAS or exposure to central venous catheters. These findings have implications for the indications for BAS, timing of surgical repair, and use of anticoagulation in TGA.

Use of Stents to Maintain Atrial Defects and Fontan Fenestrations in Congenital Heart Disease

Maintaining patent atrial septal communications or fenestrations can be vital in conditions requiring adequate decompression of the atria or Fontan baffle. We have recently deployed stents for this purpose, and the aim of this retrospective analysis is to describe our experience. All 26 patients undergoing such stent placement were retrospectively studied and for neonates with hypoplastic left heart syndrome (HLHS) and patients with Fontan fenestrations, their data were compared to controls undergoing transseptal static balloon dilation during the same time period. All 7 stented neonates with HLHS survived to their Norwood procedure and 57% survived to hospital discharge, similar to those who had static balloon dilation. Complications occurred in both HLHS groups but transient complete heart block was only seen in the control group, which also had larger balloons used (10.3 mm vs 7 mm, P=0.002). The success rate for patients undergoing stent placement in Fontan fenestrations was 64% compared to 76% with dilation alone. Complications were seen in 64% of the Fontan stented group compared to 39% for controls. There were 5 other patients with complex lesions (3 of whom were on the Extracorporeal Membrane Oxygenator) in whom stent placement successfully maintained atrial communication patency. Atrial septal stent placement in neonates with HLHS with restrictive defects is effective and appears at least as safe as static balloon dilation. On the other hand, initial fenestration stent placement is indicated only after extracardiac Fontan procedures in which the previous fenestration location cannot be found.

Creation and enlargement of atrial defects in congenital heart disease

Transcatheter creation and enlargement of interatrial defects (IAD) may improve hemodynamics; however, procedural outcomes have not been well defined. Hospital records were reviewed for children who underwent percutaneous procedures to create and enlarge an IAD and were grouped as follows: (1) right and (2) left heart obstructive lesions, (3) left atrial (LA) decompression during left heart assist, (4) failing Fontan circulation, and (5) miscellaneous. Forty-five children (mean age, 3.4 +/- 4.7 years; 30 (67%) male) were identified. In group 1 (n = 6), all achieved endpoints of right atrial (RA) decompression (n = 2), improved left ventricular filling (n = 3), or improved arterial saturations (n = 1). In group 2 (n = 18), mean LA pressure decreased (21 +/- 6 to 13 +/- 5 mmHg, p < 0.001) and arterial saturations increased (61 +/- 13% to 78 +/- 11%, p < 0.001). All except 2 patients achieved definitive repair, further palliation (n = 9), or heart transplantation (HTX) (n = 7). In group 3 (n = 5), the LA was decompressed (21 to 13 mmHg, p = 0.03) in all, and all except 1 patient survived to HTX (n = 2) or full recovery (n = 2). In group 4 (n = 11), of 7 patients with a low cardiac output syndrome after surgery, despite improved atrial shunting, 3 died and 1 required a HTX. In group 5 (n = 5), RA decompression (n = 1) or improved arterial saturation (n = 4) was achieved in all. Overall, 5-year HTX free survival was 75%. Mechanical ventilation before the procedure (p < 0.001), the need for a blade septostomy (p = 0.002), and higher LA pressures after the procedure (p = 0.04) independently predicted mortality or the requirement for HTX. Transcatheter optimization of an atrial communication can help optimize treatment strategies and has a low procedural risk.

Creation with a stent of an unrestrictive lasting atrial communication

A new technique is presented to create percutaneously an unrestrictive and lasting atrial communication in small children. In 2 infants, a stent was deployed in a restrictive atrial communication and first inflated with an 8 mm balloon. The stent was then further expanded up to 10 or 12 mm. The gradient and turbulent flow between the two atriums disappeared completely. The stent retained a very stable position without embolisation. Other complications, such as formation of thrombus or arrhythmia, were not observed until elective explantation after 2 and 11 months. We conclude that, in infants, dilation of the atrial septum with a stent can provide a safe, lasting, and unrestrictive atrial communication.

Transcatheter creation of an atrial septal defect using radiofrequency perforation

Transseptal perforation using radiofrequency energy was performed successfully in a patient with congenital heart disease and a thickened interatrial septum. This was followed by balloon dilatation of the atrial septal defect. Radiofrequency is presented as a alternative to standard transseptal needle puncture. Cathet Cardiovasc Intervent 2001;54:83-87.

Transseptal approach in children after patch occlusion of atrial septal defect: first experience with the cutting balloon

Two children required a transseptal approach to the left heart for endovascular stent redilation late after pericardial patch closure of atrial septal defects performed at the time of their initial surgical intervention. Following perforation of thickened interatrial patches in both patients, cutting balloons were used to create adequate interatrial communications. Cathet. Cardiovasc. Intervent. 48:378-381, 1999.

Blade and balloon atrial septostomy for left heart decompression in patients with severe ventricular dysfunction on extracorporeal membrane oxygenation

Extracorporeal membrane oxygenation (ECMO) is used as circulatory support or bridge to transplantation in patients with severe left ventricular (LV) dysfunction. Left heart decompression is needed to reduce pulmonary edema, prevent pulmonary hemorrhage, and reduce ventricular distention that may aid in recovery of function. We reviewed our experience from November 1993 to December 1997 with 10 patients having severe LV dysfunction (7 myocarditis, 3 dilated cardiomyopathy) who required circulatory support with ECMO and who underwent left heart decompression with blade and balloon atrial septostomy (BBAS). Patients ranged in age from 1 to 24 years (median, 3 years). Indications for BBAS included left atrial/left ventricular distension (10), pulmonary edema/hemorrhage (9), or severe mitral regurgitation (2). BBAS was performed electively in eight patients and urgently in two patients. BBAS was performed while on ECMO in seven patients and pre-ECMO in three. A femoral venous approach was used in all patients. ECMO patients were fully heparinized. Transseptal puncture was required in nine patients while one patient had a patent foramen ovale. Blade septostomy was performed in all patients. Enlargement of the defect was then performed by stationary balloon dilation in nine and Rashkind balloon atrial septostomy in one. Balloon diameters ranged from 10 to 20 mm. Sequential balloon inflations were performed in some patients. Adequacy of the atrial septal defect (ASD) was confirmed by pressure measurement and echocardiography. Adequate left heart decompression was achieved in all patients. Pulmonary edema improved in nine of nine patients. Left atrial mean pressure fell from a mean of 30.5 mm Hg, (range, 12-50 mm Hg) to 16 mm Hg (range, 9-24 mm Hg). Left atrial to right atrial pressure gradient fell from a mean of 20 mm Hg pre-BBAS to 3 mm Hg post-BBAS. ASDs ranged in size from 2.5 to 8 mm (mean, 5.9 mm). Complications included needle perforation of the left atrium without hemodynamic compromise (one), ventricular fibrillation requiring defibrillation (one), and hypotension following BBAS which responded to volume infusion (two). Duration of ECMO ranged from 41 hr to 704 hr (mean, 294 hr). Seven patients survived and four patients had recovery of normal LV function. Of those who recovered, two had no ASD at follow-up while two ASDs are patent 14 days and 3 months post-BBAS. Three patients underwent successful cardiac transplantation. Three patients died, all of whom had multisystem organ failure with or without sepsis. A patent ASD was noted at transplant (three) or autopsy (two). No patient required a second BBAS. BBAS alleviates severe left atrial hypertension and pulmonary edema. In addition, BBAS avoids the potential bleeding complications of surgical left heart decompression. Stationary balloon dilation of the atrial septum is an effective alternative to Rashkind balloon septostomy in older patients. BBAS achieves left heart decompression that may permit recovery of LV function or allow extended ECMO support as a bridge to transplant.

Prolonged extracorporeal life support for bridging to transplant: technical and mechanical considerations

Through July 1995, the Extracorporeal Life Support Organization (ELSO) registry listed 87 patients who received extracorporeal life support (ECLS) as a bridge to cardiac transplantation with a survival rate of 41%. At Arkansas Children's Hospital, 17 patients (aged between two days and 24 years) with diagnoses of dilated cardiomyopathy (seven), postcardiotomy (seven) and acute viral myocarditis (three) were bridged with ECLS. Mechanical complications only occurred in two patients, neither of which necessitated withdrawal of ECLS. Decompression of the left heart was performed in 11 patients, six via a surgically placed vent and five with a blade/balloon artial septostomy. Documented infection occurred in 11/17 patients, but only one patient died from infection. Fifteen of 17 patients (88%) recovered or were transplanted, of which 13 (76%) were discharged home. With left-heart decompression and appropriate treatment of infection, ECLS may be used as a bridge to cardiac transplantation or until the return of cardiac function.

Interventional atrioseptostomy by application of monopolar high-frequency alternating current. In vitro evaluation of a new device

RATIONALE AND OBJECTIVES

The authors evaluate the use of a new device for interventional creation of atrial septal defects (ASD) working with high-frequency alternating current in an in vitro study with porcine atria.

METHODS

The device consists of a symmetrical cage of six superelastic monofile wires, including a microthermistor that is placed via a catheter into a punctured hole in the porcine foramen ovale. The device is used as a differential electrode for monopolar, temperature-controlled application of high-frequency alternating current for thermal modelling of ASD.

RESULTS

Application of current for 60 seconds caused temperature-dependent, sized ASDs.

CONCLUSION

In vivo animal studies to evaluate possible side effects and long term patency of the ASDs are justified and warranted.