The failing Fontan circulation: successful conversion of atriopulmonary connections

Long-term Outcome of Fontan-Associated Protein-Losing Enteropathy: Treatment Modality and Predictive Factor of Mortality

We conducted the first retrospective study on Fontan-associated protein-losing enteropathy (PLE) in Korea. Fontan-associated PLE is still challenging to treat, although the survival rate has improved. There is no best treatment for PLE, and relapse occurs frequently. However, selected patients show promising results after various treatments. It would be helpful to identify the risk factors of mortality in patients with Fontan-associated PLE. High-risk patients should undergo comprehensive evaluations and receive more aggressive therapies for PLE. This study emphasizes the necessity for developing aggressive and individually targeted treatment strategies by sharing our long-term experience on Fontan-associated PLE in the current era.

Background and Objectives

Protein-losing enteropathy (PLE) is a devastating complication after the Fontan operation. This study aimed to investigate the clinical characteristics, treatment response, and outcomes of Fontan-associated PLE.

Methods

We reviewed the medical records of 38 patients with Fontan-associated PLE from 1992 to 2018 in 2 institutions in Korea.

Results

PLE occurred in 4.6% of the total 832 patients after the Fontan operation. After a mean period of 7.7 years after Fontan operation, PLE was diagnosed at a mean age of 11.6 years. The mean follow-up period was 8.9 years. The survival rates were 81.6% at 5 years and 76.5% at 10 years. In the multivariate analysis, New York Heart Association Functional classification III or IV (p=0.002), low aortic oxygen saturation (<90%) (p=0.003), and ventricular dysfunction (p=0.032) at the time of PLE diagnosis were found as predictors of mortality. PLE was resolved in 10 of the 38 patients after treatment. Among medical managements, an initial heparin response was associated with survival (p=0.043). Heparin treatment resulted in resolution in 4 patients. We found no evidence on pulmonary vasodilator therapy alone. PLE was also resolved after surgical Fontan fenestration (2/6), aortopulmonary collateral ligation (1/1), and transplantation (1/1).

Conclusions

The survival rate of patients with Fontan-associated PLE has improved with the advancement of conservative care. Although there is no definitive method, some treatments led to the resolution of PLE in one-fourth of the patients. Further investigations are needed to develop the best prevention and therapeutic strategies for PLE.

Long-term therapeutic effect of Fontan conversion with an extracardiac conduit

OBJECTIVES

The aim of this study was to identify the long-term therapeutic effect of total cavopulmonary connection (TCPC) conversion with an extracardiac conduit.

METHODS

Between 1991 and 2014, 36 patients underwent TCPC conversion with an extracardiac conduit. Half of these patients were diagnosed with tricuspid atresia or its variant. The left ventricle was dominant in 26 patients (72.2%). Median age at conversion and interval from initial Fontan operation to conversion were 24.1 years (interquartile range 18.9-29.2) and 17.8 years (15.4-20.9), respectively. Surgical cryoablation was concomitantly performed in 32 patients (88.9%). Cardiac catheter examination was performed preoperatively (36 patients, 100%) and at 1 year (31 patients, 86%), 5 years (25 patients, 69%) and 10 years (13 patients, 36%) after TCPC conversion. Symptom-limited treadmill exercise with expired gas analysis was performed preoperatively (32 patients, 88.9%) and at 1 year (27 patients, 75.0%), 5 years (20 patients, 55.6%) and 10 years (12 patients, 33.3%) after conversion.

RESULTS

All patients received follow-up; the mean follow-up period was 8.2 ± 4.8 years. Actuarial survival rate, protein-losing enteropathy-free survival rate and rate of survival with sinus rhythm maintenance at 10 years were 79.2%, 67.8% and 48.5%, respectively. The survival curve declined steeply when the duration of Fontan circulation exceeded 25 years. New cases of protein-losing enteropathy developed postoperatively in 2 patients. Permanent pacemakers were implanted in 12 patients (33%), but atrial tachyarrhythmia was not sustained in any of the remaining patients. Pulmonary arterial pressure (11.0 ± 3.1 to 9.5 ± 3.6 mmHg, P = 0.003), pulmonary vascular resistance (2.1 ± 0.7 to 1.3 ± 0.5 WU/m2, P < 0.0001) and cardiac index (2.0 ± 0.3 to 2.9 ± 0.6 l/min/m2, P < 0.0001) significantly improved from preoperative evaluation to 1 year after the conversion, and these improvements were maintained during the entire follow-up period. Peak oxygen uptake remained unchanged from the preoperative evaluation (49.7 ± 11.5% predicted) to 1 year (52.5 ± 12.0%), 5 years (56.2 ± 9.6%) and 10 years (51.2 ± 9.4%) after conversion (P = 0.19).

CONCLUSIONS

Owing to its anti-arrhythmic effect and Fontan pathway recruitment effect, TCPC conversion with an extracardiac conduit prevented the natural decline of exercise tolerance that is seen in classic Fontan patients.

Forns Index is a predictor of cardiopulmonary bypass time and outcomes in Fontan conversion

Recent reports suggested that cardiopulmonary bypass (CPB) time is one of the risk factors for postoperative complications after Fontan conversion. Although Fontan conversion may be performed for the patients with hepatic fibrosis after initial Fontan procedure, there is no predictive indicator regarding the liver function associated with hemostasis which can affects CPB time. Thirty-one patients who underwent Fontan conversion using the same surgical procedure (extracardiac conduit conversion with right atrium exclusion) were enrolled. In multivariate analyses including age at Fontan conversion, interval from initial Fontan to conversion, hemodynamic data such as right atrial pressure, ventricular end-diastolic pressure, and cardiac index, hepatic data such as platelet count, prothrombin time international normalized ratios, serum total bilirubin, hyaluronic acid levels, five known indices for hepatic fibrosis (Forns Index, APRI, FIB4, FibroIndex, and MELD-XI), and liver stiffness measured by ultrasound elastography, only the Forns Index remained independently associated with the CPB time (P < 0.01) and blood transfusions (plasma transfusions and platelet concentrations: P < 0.01 for both). The cutoff level for Forns Index to predict the prolonged CPB time (exceeding 240 min) was 4.85 by receiver-operating characteristic curve (area under the curve 0.823, sensitivity 76.9%, and specificity 72.2%). Three patients with Forns Index > 7.0 had poor outcomes with long CPB time and massive blood transfusions in contrast with the other 28 patients. In conclusion, Forns Index could serve as a practical predictor of CPB time and is associated with blood transfusion volume in Fontan conversion.

Arrhythmias in Congenital Heart Disease

Cardiac defects are the most common congenital defects, accounting for approximately 9 per 1000 births. Patients with structural heart disease related to congenital diseases are prone to develop intrinsic rhythm abnormalities as a result of altered physiology. In addition, they are at an increased risk of developing acquired arrhythmias secondary to the nature of surgical interventions done to improve physiologic function in the setting of these defects. Arrhythmia management and risk stratification pose particularly complex challenges to clinicians managing this population.

Protein-Losing Enteropathy and Plastic Bronchitis After the Fontan Operation

Protein-losing enteropathy and plastic bronchitis remain challenging to treat despite recent treatment advances. Protein-losing enteropathy and plastic bronchitis have been diagnosed in patients with cardiomyopathy, constrictive pericarditis, and congestive heart failure. This article focuses on patients with protein-losing enteropathy or plastic bronchitis following the Fontan procedure. Patients with single-ventricle physiology who have undergone the Fontan procedure are at risk for these conditions. Fontan physiology predisposes patients to chronically low cardiac output, increased central venous pressure, and congestive heart failure. These altered hemodynamics lead to increased mesenteric vascular resistance, resulting in venous hypertension and congestion in protein-losing enteropathy. Plastic bronchitis is a complex disease in which chronic high lymphatic pressures from Fontan physiology cause acellular bronchial casts to develop. These entities may also occur in patients with normal Fontan hemodynamics. This article also covers medical and surgical interventions for protein-losing enteropathy and plastic bronchitis. (Critical Care Nurse 2018;38[6]:e5-e12).

The Long-Term Management of Children and Adults with a Fontan Circulation: A Systematic Review and Survey of Current Practice in Australia and New Zealand

Although long-term survival is now the norm, Fontan patients face significant morbidity and premature mortality. Wide variation exists in long-term Fontan management. With an aim of improving their long-term management, we conducted a systematic review to identify best available evidence and gaps in knowledge for future research focus. We also surveyed cardiologists in Australia and New Zealand managing Fontan patients, to determine the alignment of current local practice with best available evidence. A systematic review was conducted using strict search criteria (PRISMA guidelines), pertaining to long-term Fontan management. All adult congenital and paediatric cardiologists registered with The Australia and New Zealand Fontan Registry were invited to respond to an online survey. Reasonable quality evidence exists for non-inferiority of aspirin over warfarin for thromboprophylaxis in standard-risk Fontan patients. No strong evidence is currently available for the routine use of ACE inhibitors, beta blockers or pulmonary vasodilators. Little evidence exists regarding optimal arrhythmia treatment, exercise restriction/prescription, routine fenestration closure, elective Fontan conversion and screening/management of liver abnormalities. Although pregnancy is generally well tolerated, there are high rates of miscarriage and premature delivery. Thirty-nine out of 78 (50 %) cardiologists responded to the survey. Heterogeneity in response was demonstrated with regard to long-term anti-coagulation, other medication use, fenestration closure and pregnancy and contraception counselling. Substantial gaps in our knowledge remain with regard to the long-term management of Fontan patients. This is reflected in the survey of cardiologists managing these patients. We have identified a number of key areas for future research.

Outcomes of Fontan conversion for failing Fontan circulation: mid-term results

OBJECTIVES

We investigated the results of a revision of a previous Fontan connection to total cavopulmonary connection (TCPC) in patients with failing Fontan circulation.

METHODS

From July 1998 to April 2013, 21 patients who had failing Fontan circulation underwent revision of the previous Fontan operation to TCPC. The median age at TCPC conversion was 17.9 years (range, 4.6-38.1 years) and the median interval between initial Fontan operation and TCPC was 13.8 years (range, 2.1-25.4 years). There were 37 indications for Fontan revision in 21 patients. The indications were huge right atrium (n = 15), atrial arrhythmia (n = 8), intra-atrial thrombi (n = 6), protein-losing enteropathy (PLE) (n = 3) and more than mild atrioventricular valve regurgitation (n = 5). The previous Fontan operation was revised to extracardiac conduit replacement (n = 20) and intra-atrial lateral tunnel (n = 1). Concomitant surgery for atrial arrhythmia was performed in 8 patients. Fenestration was performed in 7 patients. The median follow-up duration was 7.1 years (range, 0.3-13.4 years).

RESULTS

There were no operative deaths and two late deaths occurred 7.9 and 8.1 years after operation. Actuarial 5- and 10-year survival rates were 92.3 and 83.1%, respectively. Postoperative complications included bleeding (n = 3), deep sternal infection (n = 1) and prolonged pleural effusion for more than 2 weeks (n = 5). During follow-up, atrial arrhythmia recurred in 6 patients, PLE recurred in 2 patients and pleural effusion recurred in 2 patients. All patients were classified as New York Heart Association Class I (n = 15) or Class II (n = 4).

CONCLUSIONS

Fontan conversion to TCPC in patients with failing Fontan circulation can be performed with low risk of morbidity and mortality. The procedure confers better quality of life and is functional for patients with failed Fontan circulation.

Fontan Conversion

Early survival after the Fontan operation has improved significantly leading to a lifetime of Fontan circulation for patients. There is a natural progression of pulmonary artery pressure during the human lifetime that is easily tolerated in two-ventricle physiology but is deleterious for single-ventricle physiology. Obstructions in the venous to pulmonary artery pathway and pulmonary venous return or ventricular outflow, atrioventricular valve dysfunction (regurgitation), pulmonary arteriovenous malformations, venous thrombosis, and the development of atrial arrhythmias can lead to reduced functional status. These complications have been demonstrated in older patients with largely atriopulmonary connections owing to time accrual and unfavorable flow characteristics. Various surgical and catheter interventions aimed at reducing morbidity and mortality have been attempted to treat these identifiable abnormalities. The purpose of this article is to review the extant literature on Fontan Conversion and to assess the lessons learned over 20 years.

Postoperative care of the adult with congenital heart disease

An increasing number of children with congenital heart disease survive to adulthood, but many adults require surgical intervention and can present complex management challenges in the perioperative period. This review will address common considerations that surgeons, anesthesiologists, and intensivists are likely to face in caring for this growing population.

Total Cavopulmonary Connection is Superior to Atriopulmonary Connection Fontan in Preventing Thrombus Formation: Computer Simulation of Flow-Related Blood Coagulation

The classical Fontan route, namely the atriopulmonary connection (APC), continues to be associated with a risk of thrombus formation in the atrium. A conversion to a total cavopulmonary connection (TCPC) from the APC can ameliorate hemodynamics for the failed Fontan; however, the impact of these surgical operations on thrombus formation remains elusive. This study elucidates the underlying mechanism of thrombus formation in the Fontan route by using a two-dimensional computer hemodynamic simulation based on a simple blood coagulation rule. Hemodynamics in the Fontan route was simulated with Navier-Stokes equations. The blood coagulation and the hemodynamics were combined using a particle method. Three models were created: APC with a square atrium, APC with a round atrium, and TCPC. To examine the effects of the venous blood flow velocity, the velocity at rest and during exercise (0.5 and 1.0 W/kg) was measured. The total area of the thrombi increased over time. The APC square model showed the highest incidence for thrombus formation, followed by the APC round, whereas no thrombus was formed in the TCPC model. Slower blood flow at rest was associated with a higher incidence of thrombus formation. The TCPC was superior to the classical APC in terms of preventing thrombus formation, due to significant blood flow stagnation in the atrium of the APC. Thus, local hemodynamic behavior associated with the complex channel geometry plays a major role in thrombus formation in the Fontan route.

A practical and less invasive total cavopulmonary connection sheep model

Our goal was to develop a less invasive total cavopulmonary connection (TCPC) sheep model for testing total cavopulmonary assist (CPA) devices. Thirteen sheep underwent a right fourth intercostal lateral thoracotomy. In series I (n = 6), a polytetrafluoroethylene (PTFE) extracardiac conduit (ECC) was connected to inferior vena cava (IVC) and superior vena cava (SVC) by end-to-side anastomosis. The SVC/IVC remained connected to right atrium (RA). A PTFE graft bridged ECC to right pulmonary artery (RPA). Clamps between SVC/IVC anastomoses and RA diverted total venous blood to pulmonary circulation. In series II (n = 7), temporary bypasses between SVC/IVC and RA allowed SVC/IVC to be cut off from RA for better RPA exposure. The ECC-SVC/IVC were end-end anastomosed and ECC-RPA side-side anastomosed for total SVC/IVC to pulmonary artery (PA) conversion. In each series, one sheep died of bleeding. In five sheep in series I and six sheep in series II, the TCPC model was successfully created with significantly increased central venous pressure and significantly decreased PA pressure/arterial blood pressure. Our acute TCPC sheep model has a less traumatic right thoracotomy with no cardiopulmonary bypass and less blood loss with no blood transfusion, facilitating future long-term CPA device evaluation.

Clinical outcomes and improved survival in patients with protein-losing enteropathy after the Fontan operation

BACKGROUND

Patients with protein-losing enteropathy (PLE) following the Fontan operation have a reported 50% mortality at 5 years after diagnosis.

OBJECTIVES

The aim of this study was to review outcomes in patients with PLE following the Fontan operation.

METHODS

From 1992 to 2010, 42 patients (55% male) with PLE following the Fontan operation were identified from clinical databases at the Mayo Clinic. Data were collected retrospectively.

RESULTS

Mean age at PLE diagnosis was 18.9 ± 11.0 years. Initial Fontan operation was performed at 10.1 ± 10.8 years of age. Mean time from Fontan operation to PLE diagnosis was 8.4 ± 14.2 years. Survival was 88% at 5 years. Decreased survival was seen in patients with high Fontan pressure (mean >15 mm Hg; p = 0.04), decreased ventricular function (ejection fraction <55%; p = 0.03), and New York Heart Association functional class >2 at diagnosis (p = 0.04). Patients who died had higher pulmonary vascular resistance (3.8 ± 1.6 Wood units [WU] vs. 2.1 ± 1.1 WU; p = 0.017), lower cardiac index (1.6 ± 0.4 l/min/m(2) vs. 2.7 ± 0.7 l/min/m(2); p < 0.0001), and lower mixed venous saturation (53% vs. 66%; p = 0.01), compared with survivors. Factors were assessed at the time of PLE diagnosis. Treatments used more frequently in survivors with PLE included spironolactone (21 [68%]), octreotide (7 [21%]), sildenafil (6 [19%]), fenestration creation (15 [48%]), and relief of Fontan obstruction (7 [23%]).

CONCLUSIONS

PLE remains difficult to treat; however, in the current era, survival has improved with advances in treatment. Further study is needed to better understand the mechanism of disease and ideal treatment strategy.

Pediatric heart transplantation-indications and outcomes in the current era

Pediatric heart transplantation (HTx) remains an important treatment option in the care of children with end-stage heart disease, whether it is secondary to cardiomyopathy or congenital heart disease (CHD). As surgical outcomes for CHD have improved, the indications for pediatric HTx have had to be dynamic, not only for children with CHD but also for the growing population of adults with CHD. As the field of pediatric HTx has evolved, the outcomes for children undergoing HTx have improved. This is undoubtedly due to the continued research efforts of both single-center studies, as well as research collaboratives such as the International Society for Heart and Lung Transplantation (ISHLT) and the Pediatric Heart Transplant Study (PHTS) group. Research collaboratives are increasingly important in pediatric HTx as single center studies for a limited patient population may not elicit strong enough evidence for practice evolution. Similarly, complications that limit the long term graft survival may occur in a minority of patients thus pooled experience is essential. This review focuses on the indications and outcomes for pediatric HTx, with a special emphasis on studies generated by these research collaboratives.

Pediatric heart transplantation-indications and outcomes in the current era

Pediatric heart transplantation (HTx) remains an important treatment option in the care of children with end-stage heart disease, whether it is secondary to cardiomyopathy or congenital heart disease (CHD). As surgical outcomes for CHD have improved, the indications for pediatric HTx have had to be dynamic, not only for children with CHD but also for the growing population of adults with CHD. As the field of pediatric HTx has evolved, the outcomes for children undergoing HTx have improved. This is undoubtedly due to the continued research efforts of both single-center studies, as well as research collaboratives such as the International Society for Heart and Lung Transplantation (ISHLT) and the Pediatric Heart Transplant Study (PHTS) group. Research collaboratives are increasingly important in pediatric HTx as single center studies for a limited patient population may not elicit strong enough evidence for practice evolution. Similarly, complications that limit the long term graft survival may occur in a minority of patients thus pooled experience is essential. This review focuses on the indications and outcomes for pediatric HTx, with a special emphasis on studies generated by these research collaboratives.

Atrial and ventricular mechanics in patients after Fontan-type procedures: atriopulmonary connection versus extracardiac conduit

BACKGROUND

Differences in systemic venous flow dynamics and energy losses exist in various Fontan-type procedures, which may affect atrial and ventricular filling. The aim of this study was to test the hypothesis that atrial and ventricular mechanics differ between two types of Fontan procedures, atriopulmonary connection (APC) and extracardiac conduit, which have distinctly different systemic venous hemodynamics.

METHODS

This was a cross-sectional, case-control study of 28 Fontan patients (13 with APC, 15 with extracardiac conduit) aged 19.8 ± 6.5 years and 26 healthy controls. Atrial and systemic ventricular myocardial deformation was determined using speckle-tracking echocardiography, while ventricular volumes and systolic dyssynchrony index were assessed using three-dimensional echocardiography.

RESULTS

Compared with controls, patients had significantly lower values of global ventricular longitudinal, circumferential, and radial systolic strain in all three directions, reduced systolic and early diastolic strain rates (SRs) in more than one dimension, lower ejection fractions, and worse ventricular dyssynchrony. For atrial deformation, patients had lower global and positive strain and conduit and reservoir SRs and delayed electromechanical coupling. Among patients, those with APC had significantly lower ventricular longitudinal strain and early diastolic SRs, worse ventricular dyssynchrony, and reduced atrial positive and negative strain and conduit and active contractile SRs. Atrial global strain (r = 0.60, P = .001) and conduit SR (r = 0.49, P = .008) correlated positively with systemic ventricular early diastolic SR.

CONCLUSIONS

Atrial and ventricular mechanics are impaired in patients after Fontan-type operation, which is worse with APC than extracardiac conduit.

Electrophysiological interventions for treatment of congestive heart failure in pediatrics and congenital heart disease

Heart failure therapy, while well tested in the adult population, therapeutic interventions are less well defined in the pediatric population. Several treatment strategies are available for the adult patient with heart failure, thought few of these therapies have been proven in children. Morbidity and mortality in the pediatric population with a failing heart is significant, and rhythm management as well as strategies to improve hemodynamics are important in the care of these children. This review will address issues of rhythm management and resynchronization therapy in pediatric and congenital heart disease patients with heart failure.

Surgical outcome of Fontan conversion and arrhythmia surgery: Need a pacemaker?

Background

Atrial tachyarrhythmias are frequent complications in the late period after the Fontan procedure, and important risk factors for a poor prognosis. The impact of Fontan conversion and arrhythmia surgery in failed Fontan patients has been described in many reports.

Objective

We evaluated our experience with Fontan conversion procedures, concomitant arrhythmia surgery, and pacemaker implantation.

Methods

We reviewed the hospital records of 25 consecutive patients who underwent a Fontan conversion procedure from January 2004 to March 2012. Twenty-four patients had arrhythmia surgery using cryoablation and radiofrequency ablation at the time of conversion. A bilateral atrial maze procedure was performed in 6 patients, right-side maze in 15, and isthmus block in 3. Three patients with a diagnosis of corrected transposition of the great arteries underwent simultaneous pacemaker implantation electively.

Results

There was no early death and one late death during a mean follow-up period of 21.2 months. Three tachyarrhythmia recurrences developed, and there were 4 occurrences of sinus bradycardia. Five of these patients required postoperative pacemaker implantation.

Conclusion

The mid-term results of Fontan conversion and arrhythmia surgery in our institute were satisfactory. The occurrence of unexpected postoperative pacemaker requirement was high in the patients who underwent a right atrial or bilateral atrial maze procedure. Pacemaker or lead implantation is recommended for patients planned to undergo a right-side or full maze procedure.

Protein-losing enteropathy and the Fontan operation

Protein-losing enteropathy (PLE) is a complex disorder characterized by enteric protein loss and often is associated with cardiovascular abnormalities, particularly those with elevated central venous pressure. The Fontan operation is a surgical procedure used to palliate patients with a functional single ventricle. Although the Fontan operation eliminates cyanosis and decreases the workload of the functionally single ventricle, it also elevates central venous pressure. This can result in hepatic and enteric congestion as well as PLE. Despite the universal elevation in central venous pressure, only a fraction of patients who have had a Fontan operation develop PLE. However, PLE is associated with significant morbidity and mortality. Presenting signs and symptoms of PLE include abdominal bloating, diarrhea, edema, pleural effusions, ascites, and failure to thrive. In this review, the authors discuss the diagnosis and prevalence of PLE after the Fontan operation and review currently available therapeutic strategies.

Hypoplastic left heart syndrome: current considerations and expectations

In the recent era, no congenital heart defect has undergone a more dramatic change in diagnostic approach, management, and outcomes than hypoplastic left heart syndrome (HLHS). During this time, survival to the age of 5 years (including Fontan) has ranged from 50% to 69%, but current expectations are that 70% of newborns born today with HLHS may reach adulthood. Although the 3-stage treatment approach to HLHS is now well founded, there is significant variation among centers. In this white paper, we present the current state of the art in our understanding and treatment of HLHS during the stages of care: 1) pre-Stage I: fetal and neonatal assessment and management; 2) Stage I: perioperative care, interstage monitoring, and management strategies; 3) Stage II: surgeries; 4) Stage III: Fontan surgery; and 5) long-term follow-up. Issues surrounding the genetics of HLHS, developmental outcomes, and quality of life are addressed in addition to the many other considerations for caring for this group of complex patients.

12th Annual C. Walton Lillehei Memorial Lecture in Cardiovascular Surgery: Fontan conversion--the Chicago experience

Between 1994 and 2011, we performed 133 Fontan conversions with arrhythmia surgery. Most patients had tricuspid atresia or double-inlet left ventricle with prior atriopulmonary connection. Operative mortality was 1.5%, and mean length of stay was 14 days. A total of eight patients (6%) have had late cardiac transplantation. Freedom from arrhythmia recurrence is 85% at 10 years. For properly selected patients with a functionally univentricular heart who have had an atriopulmonary Fontan procedure, Fontan conversion with arrhythmia surgery significantly improves quality of life.

Fontan conversion with concomitant arrhythmia surgery for the failing atriopulmonary connections: mid-term results from a single centre

OBJECTIVES

Classical Atriopulmonary Fontan connections tend to fail in the long term due to progressive anastomotic site obstruction, right atrial enlargement, and refractory atrial arrhythmias. Conversion to total cavopulmonary connection with concomitant arrhythmia surgery is a promising treatment but optimal timing of the procedure remains controversial.

METHODS

Between the years 2002 and 2009, 15 patients with a median age of 26.2 (12-43) years underwent Fontan conversion operation with concomitant arrhythmia surgery. All were symptomatic and 14 out of the 15 patients had refractory arrhythmias. The duration of pre-operative arrhythmia and the outcome of surgery were correlated to study the impact of delay in surgical intervention on post-operative survival and arrhythmia control.

RESULTS

There were two patients who died in the early post-operative period (13.3%). At the mid-term follow-up, 53 (20-86) months, late atrial arrhythmias had recurred in two of the 13 surviving patients (15.30%) and one patient developed late sinus node dysfunction. The need for anti-arrhythmic drugs decreased considerably from 93.5% to 15.3% on mid-term follow-up. There was no late death or need for cardiac transplantation. The duration of arrhythmia before surgery was prolonged for more than 10 years in patients who died as well as in those who had complications like late recurrence of arrhythmias, dependence on anti-arrhythmic medications, and worsening of ventricular dysfunction.

CONCLUSIONS

Fontan conversion is a well-established treatment option for salvaging the failing atriopulmonary connections. Concomitant arrhythmia surgery effectively resolves the refractory atrial arrhythmias and improves survival, but we need to optimise the timing of Fontan conversion to improve the long-term outcome.

Protein-losing enteropathy: integrating a new disease paradigm into recommendations for prevention and treatment

Protein-losing enteropathy is a relatively uncommon complication of Fontan procedures for palliation of complex congenital cardiac disease. However, the relative infrequency of protein-losing enteropathy belies the tremendous medical, psychosocial and financial burdens it places upon afflicted patients, their families and the healthcare system that supports them. Unfortunately, because of the complexity and rarity of this disease process, the pathogenesis and pathophysiology of protein-losing enteropathy remain poorly understood, and attempts at treatment seldom yield long-term success. The most comprehensive analyses of protein-losing enteropathy in this patient population are now over a decade old, and re-evaluation of the prevalence and progress in treatment of this disease is needed. This report describes a single institution experience with the evaluation, management, and treatment of protein-losing enteropathy in patients with congenital cardiac disease in the current era, follows with a comprehensive review of protein-losing enteropathy, focused upon what is known and not known about the pathophysiology of protein-losing enteropathy in this patient population, and concludes with suggestions for prevention and treatment.

The Fontan pathway: What's down the road?

The Fontan circulation results from routing of the systemic venous blood to the pulmonary circulation without a hydraulic source of a ventricle. Although a hypertrophied right atrium was thought to be essential for this circulation, the current form of the operation has neither the right atrium nor any valves in the venous circulation that is connected to the pulmonary arteries directly. Modifications in the operative model was one of the early steps in improving outcome. Use of fenestration, staging of Fontan completion and better perioperative management have led to a significant drop in mortality rates in the current era. Despite this, there is late attrition of patients with complications such as arrhythmias, ventricular dysfunction, and unusual clinical syndromes of protein-losing enteropathy (PLE) and plastic bronchitis. Management of failing Fontan includes a detailed hemodynamic and imaging assessment to treat any correctable lesions such as obstruction within the Fontan circuit, early control of arrhythmia and maintenance of sinus rhythm, symptomatic treatment for PLE and plastic bronchitis, manipulation of systemic and pulmonary vascular resistance, and Fontan conversion of less favorable atriopulmonary connection to extra-cardiac total cavopulmonary connection with arrythmia surgery. Cardiac transplantation remains the only successful definitive palliation in the failing Fontan patients.

Practical stepwise approach to rhythm disturbances in congenital heart diseases

Patients with congenital heart diseases (CHD) are confronted with early- and late-onset complications, such as conduction disorders, arrhythmias, myocardial dysfunction, altered coronary flow, and ischemia, throughout their lifetime despite successful hemodynamic and/or anatomical correction. Rhythm disturbance is a well-known and increasingly frequent cause of morbidity and mortality in patients with CHD. Predisposing factors to rhythm disturbances include underlying cardiac defects, hemodynamic changes as part of the natural history, surgical repair and related scarring, and residual hemodynamic abnormalities. Acquired factors such as aging, hypertension, diabetes, obesity, and others may also contribute to arrhythmogenesis in CHD. The first step in evaluating arrhythmias in CHD is to understand the complex anatomy and to find predisposing factors and hemodynamic abnormalities. A practical stepwise approach can lead to diagnosis and prompt appropriate interventions. Electrophysiological assessment and management should be done with integrated care of the underlying heart defects and hemodynamic abnormalities. Catheter ablation and arrhythmia surgery have been increasingly applied, showing increasing success rates with technological advancement despite complicated arrhythmia circuits in complex anatomy and the difficulty of access. Correction of residual hemodynamic abnormalities may be critical in the treatment of arrhythmia in patients with CHD.

Renal function of patients with a failing Fontan circuit undergoing total cavopulmonary revision surgery

This report characterizes renal dysfunction after total cavopulmonary (TCPC) revision surgery for atriopulmonary Fontan (APF) circulations, a known risk factor for a poor outcome. The perioperative data for 23 consecutively identified patients were reviewed. The preoperative mean glomerular filtration rate (GFR) was 101 +/- 30 ml/min/1.73 m(2), decreasing to 65 +/- 41 ml/min/1.73 m(2) early in the postoperative period. The preoperative GFR was highly correlated with age at APF (r = -0.5; p = 0.024), age at TCPC (r = -0.5; p = 0.01), and mixed venous saturation (r = 0.6; p = 0.01). Three of four patients requiring renal replacement therapy (RRT) died at a median age of 3 months (range, 18 days to 9 months). Determinants of early GFR and RRT were preoperative GFR (p = 0.016) and creatinine (p = 0.035). Younger age at primary Fontan (p = 0.008), higher preoperative mixed venous saturation (p = 0.019), and higher preoperative blood pressure (p = 0.006) independently predicted better GFRs at the latest follow-up evaluation. Renal function declines acutely after TCPC revision, often necessitating RRT. A requirement for RRT marks greater mortality. Higher preoperative creatinine levels identify those at greatest risk.

Survival and prognostic factors in patients with an absent atrioventricular connection

INTRODUCTION AND OBJECTIVES

To identify anatomical and functional characteristics associated with survival in adult patients with an absent atrioventricular connection and to highlight the diagnostic importance of echocardiography.

METHODS

The clinical histories and echocardiographic and hemodynamic test results of 24 patients were recorded.

RESULTS

Some 87.5% of patients were in New York Heart Association (NYHA) functional class I/II. In 92%, the ECG demonstrated sinus rhythm and left ventricular dilatation. Chest X-ray showed grade-II cardiomegaly in 83%. Situs solitus and an absent right atrioventricular connection were found on echocardiography in 92%. The ventriculoarterial connection was most frequently concordant (in 71%). All patients had an atrial septal defect, 21 had a ventricular septal defect and 21 had decreased pulmonary flow. The ejection fraction of the main ventricle in the whole patient group was 55% +/- 10%; 52% +/- 12% in those who did not undergo surgery and 58% +/- 8% in those who did (P=NS). Factors associated with poor survival were an ostium secundum atrial septal defect, hemoglobin <16 g/dL and a main ventricle ejection fraction <50%. Of the 54% of patients who underwent surgery, 85% are alive and the majority are in NYHA functional class I/II. Among those who did not, 82% are alive and 73% are in NYHA functional class I/II.

CONCLUSIONS

The presence of a wide atrial septal defect, a normal hemoglobin level and a normal main ventricle ejection fraction were associated with the survival of these patients into adulthood. Echocardiography can provide clinicians and surgeons with information that is valuable for selecting treatment and monitoring follow-up.

Survival and prognostic factors in patients with an absent atrioventricular connection

INTRODUCTION AND OBJECTIVES

To identify anatomical and functional characteristics associated with survival in adult patients with an absent atrioventricular connection and to highlight the diagnostic importance of echocardiography.

METHODS

The clinical histories and echocardiographic and hemodynamic test results of 24 patients were recorded.

RESULTS

Some 87.5% of patients were in New York Heart Association (NYHA) functional class I/II. In 92%, the ECG demonstrated sinus rhythm and left ventricular dilatation. Chest X-ray showed grade-II cardiomegaly in 83%. Situs solitus and an absent right atrioventricular connection were found on echocardiography in 92%. The ventriculoarterial connection was most frequently concordant (in 71%). All patients had an atrial septal defect, 21 had a ventricular septal defect and 21 had decreased pulmonary flow. The ejection fraction of the main ventricle in the whole patient group was 55% +/- 10%; 52% +/- 12% in those who did not undergo surgery and 58% +/- 8% in those who did (P=NS). Factors associated with poor survival were an ostium secundum atrial septal defect, hemoglobin <16 g/dL and a main ventricle ejection fraction <50%. Of the 54% of patients who underwent surgery, 85% are alive and the majority are in NYHA functional class I/II. Among those who did not, 82% are alive and 73% are in NYHA functional class I/II.

CONCLUSIONS

The presence of a wide atrial septal defect, a normal hemoglobin level and a normal main ventricle ejection fraction were associated with the survival of these patients into adulthood. Echocardiography can provide clinicians and surgeons with information that is valuable for selecting treatment and monitoring follow-up.

Protein-losing enteropathy after Fontan operation

Protein-losing enteropathy (PLE) is a poorly understood and enigmatic disease process affecting patients with single ventricle after Fontan operation. In those afflicted, PLE after Fontan operation results in significant morbidity and mortality. The pathophysiology of the disease is unknown; however, a proposed mechanism incorporates a combination of phenomena including: (1) altered hemodynamics, specifically low cardiac output; (2) increased mesenteric vascular resistance; (3) systemic inflammation; and (4) altered enterocyte basal membrane glycosaminoglycan make-up. A paradigm for the clinical management of PLE after Fontan operation is proposed.

Arrhythmia management in the Fontan patient

With longer duration of follow-up, as many as 50% of Fontan patients will develop atrial tachycardia, usually in association with significant hemodynamic abnormalities. Arrhythmia management in the Fontan patient is reviewed. The incidence and type of arrhythmia occurrence are examined, including macro-reentrant rhythm which involves the right atrium, reentrant rhythm localized to the pulmonary venous atrium (seen in patients with lateral tunnel procedures), and atrial fibrillation. Risk factors for development of these arrhythmias are considered, and short- and long-term therapeutic options for medical and surgical treatment are discussed. Surgical results are presented for 117 patients undergoing Fontan conversion and arrhythmia surgery (isthmus ablation (9), modified right atrial maze (38) or Cox-maze III (70)). Operative mortality is low (1/117, 0.8%). Seven late deaths occurred, and include two patients who died shortly following cardiac transplantation (2/6, 33%) after Fontan conversion and arrhythmia surgery. Overall arrhythmia recurrence is 12.8% during a mean follow-up of 56 months. Fontan conversion with arrhythmia surgery can be performed with low operative mortality, low risk of recurrent tachycardia, and marked improvement in functional status in most patients. Because the development of tachycardia is usually an electromechanical problem, attention to only the arrhythmia with medications or ablation may allow progression of hemodynamic abnormalities to either a life-threatening outcome or a point at which transplantation is the only potential option. Because cardiac transplantation in Fontan patients is associated with high early mortality, earlier consideration for surgical intervention is warranted.

Hepatic fibrosis and cirrhosis in the Fontan circulation: a detailed morphological study

Aims:

To describe the histological features of the liver in patients with a Fontan circulation.

Methods:

Specimens from liver biopsies carried out as part of preoperative assessment prior to extracardiac cavopulmonary conversion of an older style Fontan were examined and scored semi-quantitatively for pertinent histological features. To support the use of the scoring, biopsy specimens were also ranked by eye for severity to allow correlation with assigned scores.

Results:

Liver biopsy specimens from 18 patients with a Fontan circulation were assessed. All specimens showed sinusoidal fibrosis. In 17 cases there was at least fibrous spur formation, with 14 showing bridging fibrosis and 2 showing frank cirrhosis. In 17 cases at least some of the dense or sinusoidal fibrosis was orcein positive, although a larger proportion of the dense fibrous bands were orcein positive compared with the sinusoidal component. All specimens showed marked sinusoidal dilatation, and 14 showed bile ductular proliferation; 1 showed minimal iron deposition, and 1 showed mild lobular lymphocytic inflammation. There was no cholestasis or evidence of hepatocellular damage. Similar appearances were observed in 2 patients with severe tricuspid regurgitation.

Discussion:

The histological features of the liver in patients with a Fontan circulation are similar to those described in cardiac sclerosis. Sinusoidal dilatation and sinusoidal fibrosis are marked in the Fontan series. The presence of a significant amount of orcein negative sinusoidal fibrosis suggests there may be a remediable component, although the dense fibrous bands are predominantly orcein positive, suggesting chronicity and permanence. No inflammation or hepatocellular damage is evident, suggesting that fibrosis may be mediated by a non-inflammatory mechanism.

Hepatic changes in the failing Fontan circulation

BACKGROUND

The failing Fontan circulation is associated with hepatic impairment. The nature of this liver injury is poorly defined.

OBJECTIVE

To establish the gross and histological liver changes of patients with Fontan circulation relative to clinical, biochemical and haemodynamic findings.

METHODS

Patients were retrospectively assessed for extracardiac Fontan conversion between September 2003 and June 2005, according to an established clinical protocol. Twelve patients, mean age 24.6 (range 15.8-43.4) years were identified. The mean duration since the initial Fontan procedure was 14.1 (range 6.9-26.4) years.

RESULTS

Zonal enhancement of the liver (4/12) on CT was more common in patients with lower hepatic vein pressures (p = 0.007), and in those with absent cardiac cirrhosis on histological examination (p = 0.033). Gastro-oesophageal varices (4/12) were more common in patients with higher hepatic vein pressure (21 (6.3) vs 12.2 (2.2) mm Hg, p = 0.013) and associated with more advanced cirrhosis (p = 0.037). The extent of cirrhosis (7/12) was positively correlated with the hepatic vein pressure (r = 0.83, p = 0.003). A significant positive correlation was found between the Fontan duration and the degree of hepatic fibrosis (r = 0.75, p = 0.013), as well as presence of broad scars (r = 0.71, p = 0.021). Protein-losing enteropathy (5/12) occurred more frequently in patients with longer Fontan duration (11.7 (3.2) vs 17.9 (6.1) years, p = 0.038).

CONCLUSIONS

Liver injury, which can be extensive in this patient group, is related to Fontan duration and hepatic vein pressures. CT scan assists non-invasive assessment. Cardiac cirrhosis with the risk of developing gastro-oesophageal varices and regenerative liver nodules, a precursor to hepatocellular carcinoma, is common in this patient group.

New Technique for Fenestration of the Interatrial Septum

Achieving controlled flow between the systemic and pulmonary venous circulations is desirable in many complex congenital heart diseases. This includes the Fontan circulation, primary pulmonary hypertension, double inlet ventricles, or hypoplastic left heart with obstruction to the atrioventricular valve. As no specific device is available for this purpose, we developed a balloon-mounted stent technique to achieve a predetermined-sized fenestration of an atrial baffle in a patient with Fontan circulation. The details of the technique are described.

Effectiveness of carvedilol for congestive heart failure that developed long after modified Fontan operation

We report a case of a patient with severe heart failure after Fontan procedure in whom carvedilol was very effective. A 27-year-old man had intractable congestive heart failure due to severe ventricular dysfunction after Fontan operation. Central venous pressure was elevated to 29 mmHg. A right-to-left shunt was noted across a large collateral vessel between the innominate vein and the pulmonary vein. He was administered carvedilol (initial dose, 2 mg/day; maximum dose, 30 mg/day). Cardiac catheterization performed 1 year after carvedilol administration revealed a decrease in atrial pressure and improvement of ventricular function. He underwent a conversion operation to total cavopulmonary connection (TCPC) and ligation of a collateral vein communicating with the innominate and pulmonary veins. Carvedilol may be a legitimate treatment before TCPC conversion or heart transplantation for the high-risk group of patients with a failed Fontan circulation.

Successful Left Ventricular Assist Device Bridge to Transplantation After Failure of a Fontan Revision

A Fontan operation will eventually fail in many patients. Fontan conversion to extracardiac conduit has been recommended but is not always successful. We present a case of a patient who went into intractable heart failure after reoperation, was rescued by left ventricular assist device implantation, and was finally bridged to heart transplantation.

Conversion of the failed Fontan circulation

Many patients with a functional univentricular heart were treated in the 1970s and 1980s, using an atriopulmonary connection to create the Fontan circulation.1–3Although this procedure, in many patients, was initially successful, and provided arterial saturations of oxygen close to normal, as these patients were followed over the years, in some cases they developed significant complications. One complication of the atriopulmonary connection is progressive right atrial dilation, which leads to atrial arrhythmias, such as atrial flutter or fibrillation.4,5The combination of these two problems leads to low cardiac output, diminished quality of life, and poor categorization within the classification of the New York Heart Association. This, and other issues, has led most centres to abandon the atriopulmonary connection as a means of creating the Fontan circulation in favour of the lateral tunnel with cavopulmonary connections,6or the extracardiac conduit.7