Risk factors in the Glenn bidirectional shunt as an intermediate procedure before Fontan correction

OBJECTIVE: The bidirectional Glenn shunt is the most common palliation before the Fontan repair, especially in high-risk patients. We studied the influence of certain risk factors in bidirectional Glenn results, with and without an additional source of pulmonary blood flow. METHODS: Between 1993 and 1998 twenty patients (6-53 months of age) underwent a bidirectional Glenn shunt as the intermediate repair for the Fontan procedure. Diagnoses were: 7 cases of double inlet single ventricle, 4 of tricuspid atresia, 3 of unbalanced AV septal defect, 4 of mitral atresia, 1 hypoplastic left heart syndrome and 1 TGA with hypoplasia of the right ventricle. 17 patients had undergone previous operations. Mean preoperative arterial oxygen saturation was 78.5%. In 6 patients an auxiliary source of pulmonary blood flow was added. RESULTS: Hospital mortality was 15%. In 4 patients the bidirectional Glenn failed. By univariate analysis low weight, preoperative functional status and high pulmonary pressure were factors associated with early death. In bidirectional Glenn failure only the duration of ventilatory support was significant. By multivariate analysis, preoperative functional status and pulmonary pressure were significant. Mean postoperative arterial oxygen saturation at a mean follow-up of 10 months was 84%. CONCLUSIONS: Bidirectional Glenn shunt is an effective and low-risk palliation for patients with univentricular hearts. Only low weight and high pulmonary pressure were significant in hospital mortality, and we advise the association of an additional source of pulmonary blood flow in these patients at the start. Early extubation provides correct performance of the shunt.     

Single ventricle palliation: greater risk of complications with the Fontan procedure than with the bidirectional Glenn procedure alone

BACKGROUND: This study was performed to evaluate and compare the early, intermediate, and long-term outcomes of the bidirectional Glenn procedure and Fontan procedure in patients who live at moderately high altitude. METHODS: The outcome of each method of palliation for patients with a functionally single ventricle was retrospectively evaluated from a review of medical records. RESULTS: The bidirectional Glenn procedure was performed in 177 patients from October 1984 to June 2004. The Fontan procedure was performed in 149 patients from June 1978 to June 2004. Cardiovascular death or heart transplantation occurred in 8% of patients after the bidirectional Glenn procedure and 17% of patients after the Fontan procedure. Complications of systemic thromboembolic events, bleeding associated with anticoagulation therapy, protein losing enteropathy, and arrhythmias requiring implantation of a pacemaker, cardioversion, or radiofrequency ablation occurred in 7% of patients after the bidirectional Glenn procedure and 47% of patients after the Fontan procedure. Cardiovascular deaths and heart transplantation occurred less frequently when the Fontan procedure was performed in patients with a previous bidirectional Glenn procedure. However, the actuarial transplant-free survival and freedom from complications was not superior for a subgroup of patients who had a Fontan procedure after a bidirectional Glenn procedure in comparison to a subgroup of patients who had a bidirectional Glenn procedure alone. CONCLUSIONS: The bidirectional Glenn procedure can be used for long-term palliation of patients with a functionally single ventricle. Additional palliation with a Fontan procedure may increase the risk of stroke, protein losing enteropathy and arrhythmias without improving survival.     

A novel technique for creation of a systemic-to-pulmonary arterial shunt

A systemic-to-pulmonary arterial shunt is still widely used for palliation of some neonates with cyanotic congenital cardiac lesions. This procedure, however, is well known to be associated with some degree of morbidity and mortality. To reduce the incidence of iatrogenic pulmonary arterial deformities, we have devised a new and simple technique to create the shunt using a partial sternotomy, and have used our technique in 10 neonates with cyanotic cardiac malformations. All but one of our patients survived, and an early reoperation was needed in only one further patient for revision of the shunt. Successful bidirectional Glenn procedures were performed in five of the nine surviving patients within 18 months of the initial procedure. We believe that our technique provides superior palliation by permitting equal enlargement of the right and left pulmonary arteries, and thus facilitates subsequent completion of the Fontan circulation.     

Outcome of Glenn anastomosis for heterotaxy syndrome with single ventricle

A retrospective study was undertaken of 157 patients who underwent a Glenn anastomosis between January 1996 and May 2001. Of these, 33 had heterotaxy syndrome: 20 males and 13 females, with a mean age of 1.26 +/- 2.8 years. Twenty-five had right atrial isomerism and 5 had left isomerism. A common atrioventricular valve was found in 24 patients, 18 had bilateral superior venae cavae, and 18 had anomalous pulmonary venous return. Repair was carried out in 8 patients with anomalous pulmonary venous return, and pulmonary artery augmentation was performed in 11. Compared to the 124 patients who had a Glenn operation for single ventricle without heterotaxy, there were significantly longer durations of mechanical ventilation, intensive care unit stay, and inotropic support, as well as higher mortality in the heterotaxy group. Heterotaxy syndrome with single ventricle still has a high rate of morbidity and mortality. Patients with severe atrioventricular valve regurgitation are at risk of early death. Complete Fontan circulation may not be possible in all patients, and Glenn anastomosis may be their final palliation.     

Growth of children with a functionally single ventricle following palliation at moderately increased altitude

The bidirectional Glenn and Fontan procedures are empirically performed as interim and definitive procedures in children with a functionally single ventricle. The optimal stage of palliation, nonetheless, remains unknown. During childhood, growth is a fundamental measure of response to therapy. Growth may be influenced by the degree of cyanosis, the volume load on the ventricle, and cardiac performance. Thus, the weight and stature of children with a functionally single ventricle who underwent a bidirectional Glenn procedure or a Fontan procedure were studied to determine the effect of each intervention on growth. Z scores for weight and stature were retrospectively determined prior to palliation, at yearly intervals for 4 years, and from long-term measurements until 18 years of age in all patients with at least 2 years of observation following palliation. Growth was evaluated in 54 patients with a bidirectional Glenn procedure, and 65 patients with a Fontan procedure. The Z scores for weight were improved after each method of surgical palliation. Stature, however, was improved only following the bidirectional Glenn procedure. Growth was impaired in patients who developed protein losing enteropathy. Weight improved only during the initial 2 years after the Fontan procedure in patients who had a surgical fenestration. Over the long-term, patients who underwent a Fontan procedure were more likely to have a Z score less than -2.0 for weight and stature than patients who underwent only a bidirectional Glenn procedure. Late mortality and the incidence of heart transplantation were increased in patients who experienced a decrease in their rate of growth, defined as a negative change of more than one Z score in weight or stature, following the Fontan procedure. In conclusion, at moderately increased altitude, children with a functionally single ventricle grow more appropriately following the bidirectional Glenn procedure than following the Fontan procedure. A decrease in the rate of growth is associated with a poor prognosis following the Fontan procedure.     

Catheter closure of accessory pulmonary blood flow after bidirectional Glenn anastomosis using Amplatzer duct occluder.

Additional source of pulmonary blood flow in patients with bidirectional cavopulmonary anastomosis (Glenn shunt) may cause elevation of the pulmonary artery pressure precluding safe completion of the Fontan operation. A case is presented with single-ventricle bidirectional cavopulmonary anastomosis and additional flow from the ventricle to the pulmonary artery resulting in elevated Glenn pressure. The communication was successfully occluded using Amplatzer duct occluder with satisfactory reduction in the Glenn pressure.     

An Unusual Cause of Irritability in a Single Ventricle Patient after Bidirectional Glenn Shunt

The differential diagnosis for irritability in children is broad. In patients with congenital heart disease, one must strongly consider cardiac etiologies such as low cardiac output or elevated central venous pressure (CVP). In patients with single-ventricle physiology, the second stage of palliation includes bidirectional Glenn, which involves anastomosis of the superior vena cava to the pulmonary artery resulting in volume offloading of the single systemic ventricle. Typically, early in the post-operative period, patients may experience a headache due to the acute increase in CVP, and symptoms improve over time. Idiopathic intracranial hypertension (IIH), also known as pseudotumor cerebri, is a rare neurologic disorder in children, characterized by raised intracranial pressure (ICP) in the absence of brain parenchymal lesions or cerebrospinal fluid (CSF) abnormalities. While the pathogenesis of IIH is unknown, early recognition and treatment of IIH are important to prevent permanent vision loss. There are only rare reports of IIH in patients with Fontan circulation. To our knowledge, we report the first case of IIH in a 2-year-old female after bidirectional Glenn.     

Designing therapeutic strategies for patients with a dominant left ventricle, discordant ventriculo-arterial connections, and unobstructed flow of blood to the lungs

The palliation of the cyanotic child with a dominant morphologically left ventricle, discordant ventriculo-arterial connections, and obstruction to the pulmonary outflow tract has continued to evolve and mature. The evolution began in the early days of surgical palliation with the Blalock-Taussig shunt, extended to construction of cavopulmonary shunts, if required, and then to the Fontan procedure and its subsequent modifications. This journey took nearly 30 years to complete. There is increasing clinical data to document the beneficial effects of this approach, with ever-improving outcomes. Some aspects of the history of the cavopulmonary shunt have been previously reviewed in this journal and elsewhere, as have analysis of outcomes for some groups of patients considered for surgical completion of the Fontan circulation. While there has been some ongoing interest in ventricular septation since the early success of Sakakibara et al., this approach has largely been abandoned. Considerably more challenges and debate resonate in the surgical algorithms defined for patients whose hearts are characterized by a dominant left ventricle, discordant ventriculo-arterial connections, and unobstructed flow of blood to the lungs. This latter group will be the focus of this review, as will the aetiology of the myocardial hypertrophy that is particularly frequent in this group of patients, its clinical recognition, indeed its anticipation, and the multiple surgical strategies designed to prevent or treat it. All these manoeuvres are considered to optimise suitability for, and outcome from, creation of the Fontan circulation.     

Catheter conversion of classic glenn to bidirectional glenn with closure of left central shunt years after surgical attempts

Bidirectional Glenn shunt is usually performed in patients with single ventricle in preparation for a total cavo‐pulmonary connection. We present a patient born with complex congenital heart disease consisting of single ventricle, pulmonary atresia, non confluent pulmonary arteries, and anomalous pulmonary venous return in whom surgical bidirectional Glenn was attempted. After multiple surgical attempts she was converted to a Classic Glenn and a central ascending aorta to left pulmonary artery shunt. Several years later by the aid of radiofrequency wire the occluded pulmonary artery segment was canalized establishing continuity between the two pulmonary artery branches with stenting of the intervening segment. The central shunt to the left pulmonary artery was subsequently embolized. Thus this patient was converted in the catheterization laboratory from the physiology of a classic Glenn to the more preferred bidirectional Glenn physiology. © 2011 Wiley Periodicals, Inc.     

Management algorithm in pulmonary atresia with intact ventricular septum.

Pulmonary atresia with intact ventricular septum (PAIVS) is a disease with remarkable morphologic variability, affecting not only the pulmonary valve but also the tricuspid valve, the RV cavity and coronary arteries. With advances in interventional techniques and congenital heart surgery, the management of PAIVS continues to evolve. This review is an attempt at providing a practical approach to the management of this disease. The basis of our approach is morphologic classification as derived from echocardiography and angiography. Group A, patients with good sized RV and membranous atresia, the primary procedure at presentation is radiofrequency (RF) valvotomy. Often it is the only procedure required in this group with the most favourable outcome. Patients with severely hypoplastic RV (Group C) are managed along the lines of hearts with single ventricle physiology. The treatment at presentation is patent ductus arteriosus (PDA) stenting with balloon atrial septostomy or conventional modified Blalock Taussig (BT) shunt. Bidirectional Glenn shunt may be done 6-12 months later followed by Fontan completion after a suitable interval. Patients in Group B, the intermediate group, are those with borderline RV size, usually with attenuated trabecular component but well developed infundibulum. The treatment at presentation is RF valvotomy and PDA stenting +/- balloon atrial septostomy. Surgical re-interventions are not uncommonly required viz. bidirectional Glenn shunt when the RV fails to grow adequately (11/2 - ventricle repair) and right ventricular outflow tract (RVOT) reconstruction for subvalvar obstruction or small pulmonary annulus. Catheter based interventions viz. repeat balloon dilatation or device closure of patent foramen ovale (PFO) may also be required in some patients.     

Surgical Improvement of Hepatic Venous Mixing to Resolve Systemic Arterial Hypoxemia Associated with Post-Fontan Pulmonary Arteriovenous Fistulae

Pulmonary arteriovenous fistulae are known to develop in patients who have functional single-ventricle heart disease and interruption of the inferior vena cava with direct hepatic drainage to the heart, in which a bidirectional Glenn shunt is the only source of pulmonary blood flow. The progressive systemic arterial hypoxemia that is associated with pulmonary arteriovenous fistulae can have important clinical consequences. Baffling the hepatic venous return to the pulmonary circulation can alleviate pulmonary arteriovenous fistulae.Herein, we present the case of a 13-year-old patient with modified Fontan anatomy and pulmonary arteriovenous fistulae, in whom redirection of a previously placed hepatic venous-to-right pulmonary artery conduit was required in order to increase systemic arterial oxygen saturation. Revision of the conduit improved mixing of hepatic venous effluent with blood flow from the bidirectional Glenn shunt. Three years after this revision, the patient''s oxygen saturation remained stable at 90%, and his physical activity was markedly improved. We present our rationale for selected redirection of the conduit and discuss other surgical options that can improve hypoxemia that is associated with pulmonary arteriovenous fistulae.Key words: Arteriovenous fistula/physiopathology/surgery, arteriovenous malformations/etiology/surgery, Fontan procedure/adverse effects/methods, heart defects, congenital/surgery, hepatic veins/physiology/surgery, postoperative complications/etiology/physiopathology/surgery, vena cava, inferior/abnormalities/surgery, pulmonary artery/surgery, regional blood flow/physiology, reoperationPulmonary arteriovenous fistula (PAVF) can develop in patients who have undergone placement of a bidirectional Glenn shunt for single-ventricle heart disease that is associated with interruption of the inferior vena cava (IVC) and direct hepatic venous drainage to the heart.^1,2 The progressive systemic arterial hypoxemia that is associated with PAVF can have important clinical manifestations. It has been reported that baffling hepatic venous return to the pulmonary circulation can alleviate PAVF. Here, we present and discuss the case of a 13-year-old modified-Fontan patient with PAVF, in whom redirection of a previously placed hepatic venous-to-right pulmonary artery (PA) conduit was required in order to overcome unfavorable streaming and to increase systemic arterial oxygen saturation levels.     

Fontan procedure--indication and clinical results

Twenty-six patients with tricuspid atresia (15), univentricular heart (7), and single ventricle (4) underwent 27 Fontan or modified Fontan procedures between 1975 and 1981. The age of the patients varied between 4 and 26 years. Twenty patients had had a total of 33 palliative operations prior to correction. The original Fontan procedure was performed in 10 patients from 1975 to 1977. According to the various anatomical findings modifications of the Fontan procedure, such as direct anastomosis or implantation of a valveless conduit, were introduced in 1977. Early mortality among all the patients was 22% (6 patients died). Three deaths occurred in the initial period 1975 to 1977. Among the last 20 patients (1978 to 1981) there were 3 early deaths. Three patients with single ventricle survived, one died due to pulmonary failure. There were 2 late deaths (sepsis, sudden cardiac death). Postoperative cardiac catheterization performed in 17 patients revealed excellent results in 13 patients; the remaining 4 displayed diminished arterial oxygen saturation, three of them had Glenn palliation prior to corrective surgery. Postoperative right atrial mean pressure varied from 10 to 23 mmHg. The left ventricular parameters were within the normal range.     

Surgical considerations of univentricular heart with total anomalous pulmonary venous connection

Out of the 600 patients undergoing univentricular repair during the last 11 years, 20 children had associated total anomalous pulmonary venous connection. The objective was to outline the clues to establish the diagnosis of this rare disease combination and the various surgical options available to manage the same. Bidirectional Glenn, bilateral bidirectional Glenn, total cavopulmonary connection and atriopulmonary connection were performed in combination with rechannelling of various types of total anomalous pulmonary venous connection in 20 children aged 6 months to 36 months (mean +/- SD 17.65 +/- 9.02 months). Diagnosis could be established pre-operatively in only 13 (65%) patients. Out of 6 early deaths (30%), 4 were directly attributable to missed diagnosis. No late deaths occurred over a follow-up period ranging from 1 month to 132 months. None of the surviving children required reoperation and all are in NYHA functional class I. Doppler echocardiography of the surviving children revealed unrestricted atrio/cavopulmonary anastomosis and pulmonary vein to atrium connection in all survivors. Our own experience, coupled with a review of the literature, indicates that a missed diagnosis increases the hospital mortality. Cross sectional 2D echocardiography is a superior method of detection of associated total anomalous pulmonary venous connection compared to angiocardiography. Exclusion of the diagnosis of anomalous pulmonary venous connection is imperative in all univentricular hearts pre-operatively and on operation table. Failure to recognise this disease combination results in formation of a closed systemic circuit after bidirectional Glenn or a modified Fontan of connection and is lethal as happened in our early experience. It is suggested that one-stage Fontan operation should be performed only if other criteria for Fontan procedure are satisfied.     

Hemiazygos Venous Additional Pulmonary Flow for Successful Total Cavo‐pulmonary Connection

Patients who underwent only Glenn procedure after being deemed unsuitable candidates for Fontan completion are not small in number, and may develop arterio‐venous (AV) pulmonary malformations during the follow‐up period. We present the case of a 17‐year‐old woman with severe systemic desaturation 13 years after Glenn procedure and repair of total anomalous pulmonary venous return. Among other anomalies, the patient disclosed hemiazygos continuation to a persistent left superior vena cava. This case supports the concept that returning flow from the abdominal vein plays an important role in the well‐balanced growth of the pulmonary artery and in the inhibition of the pulmonary AV malformation.     

Treatment of elevated pulmonary artery pressure in a child after Glenn procedure: transcatheter closure of pulmonary artery banding with subsequent sildenafil therapy

An additional source of pulmonary blood flow in a patient with bidirectional Glenn procedure (BGD) may cause elevation of mean pulmonary artery pressure (MPAP), precluding safe completion of the Fontan operation. We present a case of single ventricle physiology after pulmonary artery banding (PAB) and Glenn procedure. At the age of six years, cardiac catheterisation revealed in the patient elevated MPAP (22 mm Hg). The PAB was closed through the right internal jugular vein with an Amplatzer Atrial Septal Occluder. After the procedure, MPAP remained at a similar level. Sildenafil oral therapy was applied for six months. Subsequent heart catheterisation confirmed complete closure of PAB and decrease of MPAP to 10 mm Hg. The abovementioned complex treatment of elevated MPAP pressure in a child after Glenn therapy allowed safe completion of the Fontan operation.     

Transcatheter creation of an atriopulmonary communication in the Hemi-Fontan or Glenn circulation

There have been several modifications of the Fontan procedure, which has been used for palliation of the functionally univentricular circulation since its conception in the early 1970s. The development of intrahepatic veno-venous fistulas, pulmonary arteriovenous fistulas, and communications from the hepatic vein to the pulmonary venous atrium, are some of the complications encountered by patients with cavo-pulmonary communications. We describe transcatheter creation of an atriopulmonary communication, with simultaneous implantation of a stent, as a method of reducing or preventing pulmonary arteriovenous fistulas and associated right-to-left shunting in this setting. The intervention has been undertaken in two patients following a Hemi-Fontan procedure, itself created subsequent to a Glenn anastomosis. The combination of these procedures creates communicating atriopulmonary and cavopulmonary circulations.     

The bidirectional Glenn operation in 100 cases with complex congenital heat diseases: factors influencing surgical results]

OBJECTIVE: The bidirectional Glenn shunt is a well established surgical technique in children with complex congenital heart disease. The present study is a retrospective analysis of patients undergoing this operation in order to assess the influence of different variables in the outcome. PATIENTS AND METHOD: From December 1990 to June 2000, 100 patients received a bidirectional Glenn shunt.Two groups were defined, based on the outcome. Group A (n = 15, unsuccessfully result) including death and need to reoperate, and Group B (n = 85, patients with good outcome). RESULTS: The mortality was 8%. Eight patients were reoperated at follow-up. The survivors were followed for a mean of 3.5 years. Mean pulmonary artery pressure 7 mmHg was a factor associated with poor clinical progress. Other variables (age less than 1 year, excessive pulmonary blood flow, double Glenn operation, significant anatomic anomalies, and arrythmias), were also associated with outcome. Significant variations were observed in the time of by-pass or the need for aortic clamp in cases with simultaneous operative repair of pulmonary branch stenosis. Actuarial survival rate, most more than 1 year was 92%, and freedom from reoperation at 3 years was 90%. CONCLUSIONS: The bidirectional Glenn shunt is an excellent palliation in patients with functionally single ventricle. Mean pulmonary artery pressure was the most important variable related with the outcome. We are encouraged to continue with tendency to perform bidirectional Glenn shunt preferably early, avoiding, whenever possible, previous palliative surgery.     

Is it necessary to routinely fenestrate an extracardiac fontan?

OBJECTIVES: This study was conducted to assess the need for, and use of, fenestration of an extracardiac conduit Fontan. BACKGROUND: Fenestration of a Fontan connection has been proposed as a means of improving outcomes of single ventricle palliation. The benefit of fenestration is likely to be greatest in the early postoperative period when patients may experience increased pulmonary vascular resistance and decreased ventricular function due to the effects of cardiopulmonary bypass, aortic cross-clamping and positive pressure ventilation. However, there are potential drawbacks to fenestration. The utility of fenestration with extracardiac Fontan operation has not been determined. METHODS: Since 1992, 81 patients have undergone a modification of the Fontan procedure in which an extracardiac inferior cavopulmonary conduit is used in combination with a previously staged bidirectional Glenn anastomosis. We conducted a retrospective review of these patients. RESULTS: Fenestration was performed selectively in 32 patients (39%), including only 2 of the last 38 (5%). In seven patients, a fenestration was placed or clipped in the early postoperative period without cardiopulmonary bypass. There were two operative deaths. Prolonged (>2 weeks) pleural drainage occurred in 13 patients, 8 with fenestration and 5 without. In addition to undergoing earlier Fontan in our experience, patients who had a fenestration placed had significantly higher preoperative pulmonary vascular resistance, significantly higher common atrial pressure after Fontan and significantly lower post-Fontan systemic arterial oxygen saturation. Fontan pressure did not differ between nonfenestrated and fenestrated patients. At follow-up ranging to five years, there were two late deaths and no patients developed protein losing enteropathy. CONCLUSIONS: Fenestration is not necessary in most Fontan patients when an extracardiac conduit technique is performed as described in this article, and therefore, should not be performed routinely with the extracardiac conduit Fontan. The need for fenestration should be assessed after cardiopulmonary bypass when hemodynamics can be evaluated accurately. Fenestration can be placed and revised easily without bypass and with minimal intervention in patients with an extracardiac conduit Fontan.     

Longevity of Neonatal Ductal Stenting for Congenital Heart Diseases with Duct‐dependent Pulmonary Circulation

Introduction. Ductal stent (DS) in duct‐dependent pulmonary circulation is less morbid than neonatal Blalock–Taussig shunt. However, there is concern if DS provides an adequately long palliation before definitive repair. Methods. This is a retrospective review of clinical follow‐up of all consecutive infants after successful DS performed by a single operator. They were divided into three anatomic groups. Group A neonates had balloon valvotomy for critical pulmonary stenosis or pulmonary atresia with intact ventricular septum, who needed DS patency until the right ventricle was adequate to provide antegrade pulmonary flows. Group B patients with tetralogy of Fallot and pulmonary atresia suited for later biventricular repair needed ductal patency until conduit surgery was completed. Group C patients with functionally univentricular hearts needed DS patency until bidirectional Glenn shunt completion. Results. Among 22 infants, four Group A patients followed for 26–54 months after balloon pulmonary valvotomy had adequate oxygen saturation and needed only short‐term DS patency. In six out of nine Group B patients, corrective biventricular repair using conduits was performed after 5–14 months at a body weight of 5–7.5 kg. Bidirectional Glenn shunt and confluence repair were performed in seven of nine Group C patients weighing 6–8.5 kg after 8–15 months. The hilar pulmonary artery growth in B and C groups was adequate for surgical repair. No patient needed stent redilatations or additional shunts on follow‐up for hypoxia. Four patients had sudden death. Conclusions. The short‐term patency of DS was adequate after balloon valvotomy for critical pulmonary stenosis or pulmonary atresia with intact ventricular septum. Duration of palliation by DS was also sufficient in univentricular hearts to allow adequate somatic growth before Glenn surgery. In patients with biventricular anatomy treated by DS, conduit repair had to be performed at a relatively early age. Interstage mortality was 18%.