Clinical use of blade atrial septostomy

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.

Single Ventricle-A Comprehensive Review

In this paper, the author enumerates cardiac defects with a functionally single ventricle, summarizes single ventricle physiology, presents a summary of management strategies to address the single ventricle defects, goes over the steps of staged total cavo-pulmonary connection, cites the prevalence of inter-stage mortality, names the causes of inter-stage mortality, discusses strategies to address the inter-stage mortality, reviews post-Fontan issues, and introduces alternative approaches to Fontan circulation.

Management of Congenital Heart Disease: State of the Art-Part II-Cyanotic Heart Defects

In this review management of the most common cyanotic congenital heart defects (CHDs) was discussed; the management of acyanotic CHD was reviewed in Part I of this series. While the need for intervention in acyanotic CHD is by and large determined by the severity of the lesion, most cyanotic CHDs require intervention, mostly by surgery. Different types of tetralogy of Fallot require different types of total surgical corrective procedures, and some may require initial palliation, mainly by modified Blalock-Taussig shunts. Babies with transposition of the great arteries with an intact ventricular septum as well as those with ventricular septal defects (VSD) need an arterial switch (Jatene) procedure while those with both VSD and pulmonary stenosis should be addressed by Rastelli procedure. These procedures may need to be preceded by prostaglandin infusion and/or balloon atrial septostomy in some babies. Infants with tricuspid atresia require initial palliation either with a modified Blalock-Taussig shunt or banding of the pulmonary artery and subsequent staged Fontan (bidirectional Glenn and fenestrated Fontan with extra-cardiac conduit). Neonates with total anomalous pulmonary venous connection are managed by anastomosis of the common pulmonary vein with the left atrium either electively in non-obstructed types or as an emergency procedure in the obstructed types. Babies with truncus arteriosus are treated by surgical closure of VSD along with right ventricle to pulmonary artery conduit. The other defects, namely, hypoplastic left heart syndrome, pulmonary atresia with intact ventricular septum, double-outlet right ventricle, double-inlet left ventricle and univentricular hearts largely require multistage surgical correction. The currently existing medical, trans-catheter and surgical techniques to manage cyanotic CHD are safe and effective and can be performed at a relatively low risk.

Management of hypoplastic left heart syndrome with intact atrial septum: a two-centre experience

Introduction Hypoplastic left heart syndrome with an intact atrial septum is a poor predictor of outcomes. Prenatal assessment of pulmonary venous Doppler and emergent postnatal cardiac intervention may be associated with better outcomes. Materials and methods A retrospective review of all hypoplastic left heart syndrome patients in two centres over a 5-year period was performed. Group 1 included patients with adequate inter-atrial communication. Group 2 included patients with prenatal diagnosis with an intact atrial septum who had immediate transcatheter intervention. Group 3 included patients with intact atrial septum who were not prenatally diagnosed and underwent either delayed intervention or no intervention before stage 1 palliation. Primary outcome was survival up to stage 2 palliation.

RESULTS

The incidence of hypoplastic left heart syndrome with a restrictive atrial communication was 11.2% (n=19 of 170). Overall survival to stage 2 or heart transplantation was 85% and 67% for Groups 1 and 2, respectively (n=129/151, n=8/12; p=0.03), and 0% (n=0/7) for Group 3. Survival benefits were observed between Groups 2 and 3 (p<0.001). Foetal pulmonary vein Doppler reverse/forward velocity time integral ratio of ⩾18% (sensitivity, 0.99, 95% CI, 0.58-1; specificity, 0.99, 95% CI, 0.96-1) was predictive of the need for emergent left atrial decompression.

CONCLUSION

Using a multidisciplinary approach and foetal pulmonary vein Doppler, time-saving measures can be instituted by delivering prenatally diagnosed neonates with hypoplastic left heart syndrome with intact atrial septum close to the cardiac catheterisation suite where left atrial decompression can be performed quickly and safely that may improve survival.

Interventional and surgical therapeutic strategies for pulmonary arterial hypertension: Beyond palliative treatments

Despite significant advances in pharmacological treatments, pulmonary arterial hypertension remains an incurable disease with an unreasonably high morbidity and mortality. Although specific pharmacotherapies have shifted the survival curves of patients and improved exercise endurance as well as quality of life, it is also true that these pharmacological interventions are not always accessible (particularly in developing countries) and, perhaps most importantly, not all patients respond similarly to these drugs. Furthermore, many patients will continue to deteriorate and will eventually require an additional, non-pharmacological, intervention. In this review we analyze the role of atrial septostomy and Potts anastomosis in the management of patients with pulmonary arterial hypertension, we summarize the current worldwide clinical experience (case reports and case series), and discuss why these interventional/surgical strategies might have a therapeutic role beyond that of a "bridge" to transplantation.

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.

Consensus on timing of intervention for common congenital heart diseases: part II - cyanotic heart defects

The purpose of this review/editorial is to discuss how and when to treat the most common cyanotic congenital heart defects (CHDs); the discussion of acyanotic heart defects was presented in a previous editorial. By and large, the indications and timing of intervention are decided by the severity of the lesion. While some patients with acyanotic CHD may not require surgical or transcatheter intervention because of spontaneous resolution of the defect or mildness of the defect, the majority of cyanotic CHD will require intervention, mostly surgical. Total surgical correction is the treatment of choice for tetralogy of Fallot patients although some patients may need to be palliated initially by performing a modified Blalock-Taussig shunt. For transposition of the great arteries, arterial switch (Jatene) procedure is the treatment of choice, although Rastelli procedure is required for patients who have associated ventricular septal defect (VSD) and pulmonary stenosis (PS). Some of these babies may require Prostaglandin E1 infusion and/or balloon atrial septostomy prior to corrective surgery. In tricuspid atresia patients, most babies require palliation at presentation either with a modified Blalock-Taussig shunt or pulmonary artery banding followed later by staged Fontan (bidirectional Glenn followed later by extracardiac conduit Fontan conversion usually with fenestration). Truncus arteriosus babies are treated by closure of VSD along with right ventricle to pulmonary artery conduit; palliative banding of the pulmonary artery is no longer recommended. Total anomalous pulmonary venous connection babies require anastomosis of the common pulmonary vein with the left atrium at presentation. Other defects should also be addressed by staged correction or complete repair depending upon the anatomy/physiology. Feasibility, safety and effectiveness of treatment of cyanotic CHD with currently available medical, transcatheter and surgical methods are well established and should be performed at an appropriate age in order to prevent damage to cardiovascular structures.

Palliative procedures for congenital heart defects

Although total repair of some congenital heart defects is possible in young children, palliative procedures still play an important role in relieving patients' symptoms, particularly in emergent settings, when total correction or surgical repair is not available. However, the concepts and taxonomies of the palliative procedures for congenital heart diseases sometimes seem to be ambiguous and confusing for young cardiac surgeons and cardiologists. This article gives a full-scope overview of the concepts, categories, indications, historical developments and clinical outcomes of the palliative procedures for congenital heart defects that have been documented in the literature. In total, there are 21 palliative procedures for the surgical management of congenital heart defects, which can be classified into four categories: firstly, increasing pulmonary artery flow for pulmonary oligaemia (including shunt procedures); secondly, decreasing pulmonary artery flow for pulmonary overcirculation (pulmonary banding and Norwood procedure); thirdly, enhancing intracardiac blood-oxygen mixture for systemic hypoxaemia (atrial septostomy subjected to different techniques); and, finally, other procedures, including congenital mitral or aortic stenosis palliation, coarctation of aorta palliation and hybrid palliative procedures for hypoplastic left heart syndrome. Modified Blalock-Taussig's and Glenn's shunts and pulmonary artery banding represent the pre-eminent palliative procedures for congenital heart defects and have been proven to be satisfactory after long-term clinical application. It seems that there is a growing trend towards the use of interventional techniques with stent deployment as an alternative to the surgical approach.

Restrictive tunnel patent foramen ovale and left atrial hypertension in single-ventricle physiology: implications for stent placement across the atrial septum

Our objective is to describe our approach to the management of patients with single-ventricle physiology and restrictive tunnel patent foramen ovale (TPFO) with unfavorable atrial septal morphology. We describe a series of five patients with single-ventricle physiology and restrictive TPFO and our experience with radiofrequency perforation (RFP), static balloon atrial septostomy (BAS), and stent implantation to create an alternative pathway for left atrial decompression. Between July 4, 2006, and July 10, 2007, five patients with single-ventricle physiology and restrictive TPFO were brought to the cardiac catheterization laboratory for decompression of a hypertensive left atrium. Four of five patients underwent RFP followed by static BAS and stent implantation across the newly created atrial communication. One patient had a stent placed across an existing TPFO. Unfortunately, stable stent position was not achieved in this case, and the patient required open atrial septectomy. In patients with single-ventricle physiology and a restrictive TPFO associated with left atrial hypertension, stent placement across the existing defect can result in unstable stent position. Using a RFP wire to create a new defect in the septum primum allows stable stent deployment across the atrial septum and achieves left atrial decompression.

Percutaneus double stent atrial septostomy

Graded balloon septostomy, bladed atrial septostomy, fenestrated Amplatzer devices and stent placement have been reported to obtain stable interatrial communications. We expose our favorable experience creating an interatrial septal defect, by the use of two stents concentrically placed. We think it can be a procedure to be taken into account whenever a wide interauricular septal orifice must be achieved.

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.

Novel approach to the newborn with hypoplastic left heart syndrome and intact atrial septum

A prenatally diagnosed fetus with hypoplastic left heart syndrome and intact atrial septum was delivered in the cardiac catheterization suite. Using radio frequency energy, a transseptal perforation of the thickened and intact atrial septum was immediately performed following transcatheter cannulation of the right atrium via the umbilical vein. Serial cutting balloon septostomies followed by static balloon septostomies resulted in effective left atrial decompression, atrial mixing, and optimal pulmonary and systemic perfusion. The child is now thriving after both stage I Norwood and bidirectional Glenn procedures.

Three-dimensional echocardiography–guided atrial septectomy: An experimental study

OBJECTIVES

The surgical feasibility of beating-heart atrial septectomy under the guidance of two different types of real-time 3-dimensional echocardiography systems was examined.

METHODS

A modified real-time 3-dimensional echocardiography system with a x4 matrix transducer (Sonos 7500; Philips Medical Systems, Andover, Mass) or a mechanical 1-dimensional array transducer (SSD-5500; Aloka Co, Ltd, Tokyo, Japan) was used. Small porcine atrial septal defects (n = 8) were enlarged with a Kerrison bone punch in the tank model. In the animal studies, small atrial septal defects (n = 8) were enlarged with the same device through a transatrial port. In both experiments, the area of the atrial septal defect measured by real-time 3-dimensional echocardiography was compared with the area measured directly.

RESULTS

Real-time 3-dimensional echocardiography provided satisfactory images and sufficient anatomic detail for the atrial septectomy in both experimental settings. All the atrial septal defects were successfully enlarged; an increase of as much as 293% of the preoperative atrial septal defect area was achieved in the tank experiment, and an increase of as great as 449% of the preoperative area was achieved in the animal experiment. The size of the atrial shunt was increased significantly after the atrial septectomy relative to that before the surgery (P <.0001). The percentage enlargement of the atrial septal defect measured by real-time 3-dimensional echocardiography was strongly correlated with that measured directly (both r(2) = 0.997, P <.0001) Bland-Altman analysis showed close agreement between the results obtained by the two measurement methods in both models.

CONCLUSIONS

Real-time 3-dimensional echocardiography provides satisfactory images and sufficient anatomic detail for atrial septectomy. This experiment demonstrates the surgical feasibility of a beating-heart intracardiac procedure such as atrial septectomy under real-time 3-dimensional echocardiographic guidance.

Pulmonary Atresia with Intact Ventricular Septum

The prognosis for patients with pulmonary atresia with intact ventricular septum is poor with and without conventional surgical treatment. Because of this reason, a comprehensive program of medical, transcatheter, and surgical treatment is necessary to improve the long-term outlook of these infants. Algorithms of management plans should be developed based on the presence of right ventricular-dependent coronary circulation as well as size and morphology of the right ventricle. In a tripartite or bipartite right ventricle, transcatheter radiofrequency perforation is preferable. Alternatively, surgical valvotomy may be performed. Augmentation of pulmonary blood flow by prolonged infusion of prostaglandin E(1), stenting the ductus, or a surgical modified Blalock-Taussig shunt may be necessary in some of these patients. In patients with a unipartite or very small right ventricle or a right ventricular-dependent coronary circulation (Tricuspid valve Z score < -2.5), augmentation of pulmonary flow along with atrial septostomy should be undertaken. Follow-up studies to determine the feasibility of biventricular repair should be undertaken and, if feasible, surgical or transcatheter methods may be used to achieve the goals. If not suitable for biventricular repair, one-ventricle (Fontan) or one and one-half ventricular repair should be considered. Comprehensive and well-planned treatment algorithms may help improve survival rate.

Radiofrequency perforation in the treatment of congenital heart disease

Catheter-directed perforation of cardiac tissue with radiofrequency (RF) energy has expanded the horizon of the interventional cardiologist dealing with congenital heart disorders. The focus of the following discussion will be to detail the biophysical basis behind RF perforation and review its application in the management of congenital heart lesions.

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.

Transcatheter intervention in the neonate with congenital heart disease

Over the past 30 years, interventional cardiology has developed as a distinct subspecialty, playing a major role in the management of infants with CHD. In the neonatal period, a wide variety of transcatheter interventions are performed routinely, either as palliation or therapy, as adjunct to surgery, or in place of surgical intervention. Among these are creation or enlargement of ASDs to allow atrial mixing; balloon valvotomy to treat congenital valvar stenoses; balloon angioplasty or stenting of stenotic vessels (pulmonary arteries, coarctation of aorta, or systemic or pulmonary veins) or postoperative anastomoses; closure of [figure: see text] unwanted vessels (congenital fistulae or collaterals); and other miscellaneous interventions. A wide variety of patients are candidates for these procedures, including those with transposition of the great arteries or other defects with transposition physiology, left atrial outlet obstruction and hypertension, severe valvar pulmonary or aortic stenosis, hypoplastic stenotic pulmonary arteries with severe symptomatology, severe coarctation of aorta and high surgical risks, large aortopulmonary collaterals or other hemodynamically significant unwanted vessels, acute thrombosis of certain surgical anastomoses, and many more. In experienced hands, these procedures are highly successful and safe, with a low morbidity and mortality (less than 1%).

Transesophageal echocardiographic guidance of blade atrial septostomy in children

Transesophageal echocardiography (TEE) was used to guide blade atrial septostomy in children requiring decompression of right or left atrium. In conjunction with biplane fluoroscopy, TEE was used to position the blade septostomy catheter and to monitor the pullback from left atrium to right atrium. Subsequent balloon dilatation of atrial septum was also carried out under TEE control. The use of TEE monitoring facilitated the procedure by providing optimal views of intracardiac structures while also limiting the total radiation exposure.

Tricuspid Atresia

Untreated, the prognosis for patients with tricuspid atresia (TA) is poor. Recent advances in medical and surgical therapy, particularly the application of Fontan principle, have markedly improved the long-term outlook for children with this condition. Palliative procedures to normalize the pulmonary blood flow and to relieve interatrial or interventricular obstruction should be undertaken promptly. Staged total cavopulmonary connection to bypass the right atrium and right ventricle by an initial bidirectional Glenn procedure and followed by extracardiac conduit diversion of inferior vena caval flow into the pulmonary arteries appears to be the current procedure of choice in the surgical management of TA. Total cavopulmonary diversion appears to be superior to conventional Fontan-Kreutzer operations, but long-term follow-up results are needed to confirm this impression.

Recommendations of the British Paediatric Cardiac Association for therapeutic cardiac catheterisation in congenital cardiac disease

The aims of these recommendations are to improve the outcome for patients after, and to provide acceptable standards of practice of therapeutic cardiac catheterisation performed to treat congenital cardiac disease. The scope of the recommendations includes all interventional procedures, recognising that for some congenital malformations, surgical treatment is equally as effective as, or occasionally preferable to, interventional treatment. The limitations of the recommendations are that, at present, no data are available which compare the results of interventional treatment with surgery, and certainly none which evaluate the numbers and types of procedures that need to be performed for the maintenance of skills. Thus, there is a recognised need to collect comprehensive data with which these recommendations could be reviewed in the future, and re-written as evidence-based guidelines. Such a review will have to take into account the methods of collection of data, their effectiveness, and the latest developments in technology. The present recommendations should, therefore, be considered as consensus statements, and as describing accepted practice, which could be used as a basis for ensuring and improving the quality of future care.

Congenital Heart Surgery Nomenclature and Database Project: therapeutic cardiac catheter interventions

The extant nomenclature for therapeutic cardiac catheter interventions is reviewed for the purpose of establishing a unified reporting system. The subject was debated and reviewed by members of the STS-Congenital Heart Surgery Database Committee and representatives from the European Association for Cardiothoracic Surgery. All efforts were made to include all relevant nomenclature categories using synonyms where appropriate. A comprehensive database set is presented which is based on a hierarchical scheme. Data are entered at various levels of complexity and detail which can be determined by the clinician. These data can lay the foundation for comprehensive risk stratification analyses. A minimum database set is also presented which will allow for data sharing and would lend itself to basic interpretation of trends. Outcome tables relating diagnoses, procedures, and various risk factors are presented.

Interventional procedures for congenital heart disease

Interventional techniques available for use in treating congenital heart disease include balloon dilation of valves and vessels, stent placement and coil embolization of collaterals, patent ducts and other arterial fistulae. In addition, a variety of devices for closure of atrial and ventricular septal defects and patent ducts currently are under investigation. Radiofrequency ablation of arrhythmias also is applicable to the pediatric population.

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.

Percutaneous balloon dilatation of the atrial septum: immediate and midterm results

OBJECTIVES

To assess the effectiveness of atrial septostomy by percutaneous balloon dilatation in patients with congenital heart defects or primary pulmonary hypertension.

PATIENTS AND DESIGN

Twenty three patients (15 boys, eight girls; aged 10 days to 10 years; 17 with congenital heart defects and six with primary pulmonary hypertension), all haemodynamically unstable under optimal medical treatment, underwent atrial septostomy by percutaneous balloon dilatation.

INTERVENTIONS

The balloon catheter entered the left atrium through a patent foramen ovale (n = 14) or via transseptal puncture in cases with an intact atrial septum (n = 9). The size of the balloons used ranged from 13 to 18 mm.

RESULTS

There were no complications. The interatrial communication (mm) increased (P < 0.05) after dilatation and remained unchanged (P = NS) during a 16.6 (13.8) month follow up (2 (1.7) v 8.8 (1.4) v 8.2 (1.1), respectively). Transatrial gradient (mm Hg) fell and arterial oxygenation (%) improved both in patients with transposition (6.3 (0.8) v 0.8 (1) (P = 0.0001) and 40.6 (4.2) v 76.5 (4.8) (P = 0.0001), respectively) and in those with mitral atresia (13.4 (1.9) v 2 (1.4) (P = 0.0001) and 77.1 (3.9) v 81.5 (4.2) (P = 0.008), respectively). There were two failures, one early and one late, both in the group of patients with mitral atresia or stenosis. A decrease in arterial oxygenation (94.8 (1.5) v 83 (2.4), P = 0.004) and an increase in left atrial pressure (6.8 (0.9) v 8.3 (1.2), P = 0.02) and cardiac index (2.3 (0.2) v 3.1 (0.2) l/min/m2, P = 0.002) was observed in patients with primary pulmonary hypertension.

CONCLUSIONS

Percutaneous balloon dilatation is an effective and safe procedure for creating an adequate interatrial communication that can be used as an alternative to blade septostomy.

A novel method to create atrial septal defect using a cutting balloon in piglets

A new method of creating atrial septal defect, using a 3- or 4-blade cutting balloon catheter combined with conventional static balloon dilation, is discussed. Radially directed surgical cuts made in the atrial septum were enlarged by balloon angioplasty, producing defects measuring 3 to 8 mm, with a mean Qp/Qs of 1.96/L.

Closed atrial septectomy with Brock punch aided by operative transesophageal echocardiography

A 5-week-old infant with mitral atresia and double-outlet right ventricle underwent blade atrial septostomy complicated by cardiac tamponade. Surgical septectomy was performed using a Brock punch aided by intraoperative transesophageal echocardiography. This was well tolerated, and the adequacy of the septectomy could be assessed immediately.

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

A new approach to creating an interatrial communication using a stationary fixed-diameter angioplasty balloon is presented. Stationary balloon septostomy was used to create an atrial communication in 19 young swine using a transseptal technique through a closed atrial septum, and in 18 newborn lambs through a patent foramen ovale. In animals with an intact septum, there was persistent patency of the atrial communication using balloons larger than 12 mm in diameter. The average diameter of the atrial communication was 96% of the expanded diameter of the angioplasty balloon. For newborn lambs with a patent foramen, a smooth oval atrial communication was noted by 4 weeks, and there was persistent patency of the opening using balloons larger than 15 mm in diameter. The average diameter of the opening was 81% of the diameter of the angioplasty balloon used. The new procedure was used successfully in five patients. All five showed resolution of the clinical symptomology. In conclusion, stationary angioplasty balloon atrial septostomy has been effective in producing interatrial communications, which remained patent for 4-14 weeks, in animals with intact septum, as well as in those with a patent foramen ovale.

Transcatheter laser atrial septostomy in rabbits

The feasibility of percutaneous transluminal catheter-directed laser (Argon multiline 488/514 nm) atrial septostomy under echocardiographic guidance was studied in eight rabbits. In five animals the interatrial septum was exposed to laser energy for 30 s (n = 1) or for 10 s (n = 4) by using the continuous wave (cw) mode of irradiation. In the other three animals chopped mode of irradiation was applied for 10 s at 7 W. Echocardiography allowed visualization of both atrial cavities and the interatrial septum, the tip of the catheter including the optical fiber tip as well as the flow direction of contrast echoes during the laser firing. Blood clotting with thrombus formation was present following the cw mode of irradiation. The defects created in the interatrial septa of < or = 0.3 mm in diameter had irregular black borders and, histopathologically, were surrounded by a zone of coagulation necrosis of < or = 0.2 mm and vacuolization (vacuoles of < 0.1 mm in diameter). After 30 s of lasering a huge defect was conspicuous in the interatrial septum which extended up to the right and left atrial roof. The chopped mode of irradiation induced less blood clotting and narrow channels of < or = 0.08 mm through the interatrial septa with a small zone of coagulation necrosis of < or = 0.05 mm and without carbonization and vacuolization. This study demonstrates that laser atrial septostomy is technically feasible. However, prior to the extension of the method to humans, further investigation especially considering other laser power sources, possibly more suitable for this application such as Neodymium-YAG or Excimer lasers is warranted.

Transcatheter management of cyanotic congenital heart defects: a review

In this review, the role of transcatheter methods in the management of cyanotic congenital heart defects is discussed. In patients with interventricular right-to-left shunting secondary to pulmonary outflow tract obstruction (most commonly tetralogy of Fallot), balloon dilatation may be an effective palliative procedure in a substantial proportion of patients, obviating the need for a palliative shunt. We would recommend this if the patient's size or cardiac anatomy makes that patient an unsuitable candidate for safe total surgical correction. Infundibular myectomy with atherectomy catheter in tetralogy of Fallot patients may become a useful adjunct in the management of these infants. Cyanotic children with interatrial right-to-left shunt secondary to severe valvar pulmonary stenosis respond to balloon pulmonary valvuloplasty in a manner similar to that seen with isolated pulmonary valve stenosis. In these patients, balloon valvuloplasty is the treatment of choice and may be corrective in most cases. In patients with a narrowed Blalock-Taussig shunt, balloon angioplasty may improve pulmonary oligemia and systemic arterial hypoxemia and may obviate the need for a second systemic-to-pulmonary artery shunt. Balloon angioplasty is recommended if the patient's cardiac defect is not amenable to surgical correction at a low risk either because of the size of the patient or because of the complexity of the cyanotic heart defect. In patients with pulmonary valve atresia, initial opening of the atretic pulmonary valve by either laser or surgery with subsequent balloon dilatation is potentially beneficial in reducing the total number of surgical procedures that these children are likely to require. However, further clinical trials are needed prior to their general use.

Surgical management of congenital heart defects: current trends

Surgical treatment for congenital heart disease has become available over the last five decades. Palliative procedures have been designed to improve physiologic abnormalities, for example systemic artery (or venous) to pulmonary artery shunts of various types to increase the pulmonary blood flow, pulmonary artery constriction (banding) to decrease the pulmonary blood flow, and surgical or transcatheter atrial septostomy to augment intracardiac mixing. These can be performed with a low mortality. The majority of congenital heart defects can be corrected by open heart surgical techniques; some require prior palliation and others can be operated without prior palliative surgery. Recent surgical advances include early total surgical correction for tetralogy of Fallot, arterial switch procedure for transposition of the great arteries, Fontan operation and its modifications for tricuspid atresia and single ventricle, new operations for hypoplastic left heart syndrome, newer prosthetic valves, myocardial preservation and cardiac transplantation.

Blade atrial septostomy: experience with the first 50 procedures

We have performed 50 blade and balloon atrial septostomies in 46 patients with diagnoses of transposition of the great arteries--32 patients; mitral atresia or stenosis--10 patients; total anomalous pulmonary venous drainage--2 patients; tricuspid atresia--1 patient; and pulmonary valve atresia with hypoplastic right ventricle--1 patient. The patients' age ranged from 1 day to 72 months (median = 8 months) and weights ranged from 2.7 to 14.5 kg. In patients with transposition the systemic saturation increased from an average of 62% to 74.6% (p less than 0.001) and the inter-atrial mean pressure gradient was reduced from 7.74 +/- 5.3 to 1.4 +/- 2.04 mm Hg. Patients with mitral atresia had no significant increase in systemic arterial saturation but a significant decrease in the mean inter-atrial gradient from 19.6 +/- 12.4 to 3.8 +/- 5.3 mm Hg. In three patients the blade septostomy was unsuccessful for technical reasons and the condition of the patient. Complications included one death due to atrial laceration, blood loss requiring transfusion in 5 patients, transient CVA in one patient, and failure of the blade to close in one patient. We have found the palliative use of the blade catheter in conjunction with balloon atrial septostomy to be an effective and safe procedure.

Balloon dilation catheters

Catheter therapy has gained an important role in the treatment of congenital heart disease. The cumulative experience with vascular and valvular balloon dilations has demonstrated low mortality and morbidity with short-term results similar to surgery. Currently, balloon dilation is an accepted treatment for valvular pulmonary stenosis, distal pulmonary artery stenosis, recurrent coarctation, rheumatic mitral stenosis, congenital valvular aortic stenosis, and intra-atrial baffle obstruction. Except for patients at high surgical risk, balloon dilation of native coarctation is considered investigational at most institutions but accepted at others. No conclusive evaluation is yet possible for dilation of bioprosthetic valves and membranous subaortic stenosis. Individual pulmonary veins appear undilatable. Various devices are available for closure of extra- and intracardiac communications. Transcatheter closure of aortopulmonary collaterals and arteriovenous malformations is now well established at some centers. In selected patients, therapeutic embolization of surgical shunts can replace surgery. Transcatheter closure of the patent ductus arteriosus has become routine at some centers. Nonsurgical closure of atrial and ventricular septal defects has entered clinical trials, and preliminary results appear very promising. Blade atrioseptostomy and foreign body retrieval are well established. Improvement of existing procedures and implementation of new concepts will consolidate the role of catheter therapy in congenital and acquired heart disease.

Transcatheter closure of atrial septal defects. Experimental studies

Recent experience with the spring-loaded patent ductus arteriosus (PDA) occluder has demonstrated several advantages of this device in the closure of intracardiac defects compared with previously described techniques. Pathologic and animal model studies were performed to identify which atrial septal defects (ASDs) might be suitable for device closure and to test a new septal closure double umbrella. Fifty specimens from the Cardiac Registry with unrepaired ASD secunda (2 degrees) were analyzed. Mean ASD size was 8 x 10 mm (range, 3 x 4 to 30 x 30 mm); 80% (n = 40) of ASDs were judged closable with the new device. ASD closure was attempted in four lambs with the Rashkind (hooked single umbrella) ASD occluder. One of four umbrellas was correctly positioned; no ASDs were closed. A new double-hinged ("clamshell") umbrella device was designed: eight ASD closures were attempted with this device (defects ranged from 8 to 20 mm in diameter). Six of eight umbrellas were correctly positioned; four of four animals observed more than 1 day appeared to have complete closure on postmortem examination with endothelialization of the device. We conclude that 1) most ASD 2 degrees are far enough from vital structures to permit closure, 2) initial placement of hooked umbrellas is often incorrect and cannot be altered, 3) clamshell double umbrellas were successfully placed in six of eight attempts, and 4) endothelialization of closed ASDs appears complete within weeks of implantation. These preliminary studies appear promising and support testing the clamshell ASD device in clinical trials.

Creation and maintenance of an adequate interatrial communication in left atrioventricular valve atresia or stenosis

Patients with left atrioventricular (AV) valve atresia or stenosis were studied retrospectively to determine the incidence of early and late failures of procedures to enlarge an interatrial communication. The 61 patients underwent 80 procedures: 5 balloon atrial septostomies, 12 blade atrial septostomies and 63 surgical septectomies. No balloon septostomy provided adequate long-term palliation. Of 12 blade septostomies, 4 resulted in gradients across the atrial septum of 5 to 8 mm Hg and 8 in gradients 3 mm Hg or less. Results from blade septostomy were unrelated to underlying diagnosis, age, gradient before the procedure, number of previous procedures, pulmonary blood flow or size of the postprocedure defect by balloon sizing, but were related to size of the postoperative defect estimated by echocardiography. Among 8 patients with gradients of 3 mm Hg or less after blade septostomy, 7 were followed 9 +/- 7 months and showed no evidence of restenosis. Of 63 surgical septectomies, 11 (17.5%) were inadequate, and in at least 7 cases the failure was due to restenosis of the defect as documented by serial catheterizations or echocardiograms. Outcome after surgical septectomy was unrelated to underlying diagnosis, age or number of previous procedures, but was related to size of the defect created. Our results reveal improved results in terms of residual gradient for blade septostomy compared with previous studies and the need to follow these patients carefully, even those undergoing surgical septectomy.

Interventional procedures in congenital heart disease

Balloon septostomy changed the natural history of transposition of the great arteries. Relatively little more occurred in catheter treatment of congenital heart disease until the development of the balloon catheter for transluminal angioplasty. Modification of these catheters led to successful treatment of valvular pulmonic stenosis, peripheral pulmonic stenosis, and coarctation restenosis. Possible future applications of balloon valvuloplasty include valvar aortic stenosis, stenotic shunts, and palliative operations. Pulmonary arteriovenous malformations are well managed by detachable balloon techniques, and balloons and coils are used for occluding large systemic collaterals. Interventional techniques have made a significant impact on the treatment of congenital heart disease, and it is anticipated that as technology improves further advances will occur.

Progressive obstruction of the foramen ovale in patients with left atrioventricular valve atresia

Thirteen patients with left atrioventricular (AV) valve atresia and a normal aortic root were studied to evaluate the status of the interatrial communication with advancing age. Six patients had cardiac catheterization within the first 2 weeks of age; of these, five had repeat studies before 7 months of age. The seven other patients initially underwent catheterization after 2 weeks of age. In the group with catheterization before 2 weeks of age, the mean left atrial pressure was 7.8 +/- 5.5 mm Hg and the left atrial-right atrial mean pressure gradient was 1.7 +/- 2.4 mm Hg. In the combined group of patients with catheterization after 2 weeks of age, the mean left atrial pressure was 25.9 +/- 5.6 mm Hg and the mean left atrial-right atrial pressure gradient was 21.1 +/- 5.1 mm Hg. Seven of the 13 patients have survived and have now reached a median age of 6.5 years. Balloon atrial septostomy was adequate for long-term survival in one patient; all of the others have required surgical atrial septectomy. Progressive obstruction of the foramen ovale is part of the natural history of left AV valve atresia, and obstruction develops despite the absence of a left atrial-right atrial gradient during newborn study. Balloon atrial septostomy is recommended during the neonatal period in all patients with left AV valve atresia, even in the absence of an interatrial gradient. Because early surgical atrial septectomy is usually necessary for long-term survival, these patients should have serial noninvasive evaluation of the patency of the interatrial communication.