Rare problems associated with the Fontan circulation

Effect of patient factors, center, and era on Fontan timing: An observational study using the Pediatric Health Information Systems Database

BACKGROUND

There are no consensus guidelines defining optimal timing for the Fontan operation, the last planned surgery in staged palliation for single-ventricle heart disease.

OBJECTIVES

Identify patient-level characteristics, center-level variation, and secular trends driving Fontan timing.

METHODS

A retrospective observational study of subjects who underwent Fontan from 2007 to 2021 at centers in the Pediatric Health Information Systems database was performed using linear mixed-effects modeling in which age at Fontan was regressed on patient characteristics and date of operation with center as random effect.

RESULTS

We included 10,305 subjects (40.4% female, 44% non-white) at 47 centers. Median age at Fontan was 3.4 years (IQR 2.6-4.4). Hypoplastic left heart syndrome (-4.4 months, 95%CI -5.5 to -3.3) and concomitant conditions (-2.6 months, 95%CI -4.1 to -1.1) were associated with younger age at Fontan. Subjects with technology-dependence (+4.6 months, 95%CI 3.1-6.1) were older at Fontan. Black (+4.1 months, 95%CI 2.5-5.7) and Asian (+8.3 months, 95%CI 5.4-11.2) race were associated with older age at Fontan. There was significant variation in Fontan timing between centers. Center accounted for 10% of variation (ICC 0.10, 95%CI 0.07-0.14). Center surgical volume was not associated with Fontan timing (P = .21). Operation year was associated with age at Fontan, with a 3.1 month increase in age for every 5 years (+0.61 months, 95%CI 0.48-0.75).

CONCLUSIONS

After adjusting for patient-level characteristics there remains significant inter-center variation in Fontan timing. Age at Fontan has increased. Future studies addressing optimal Fontan timing are warranted.

Pulmonary Complications in Patients With Fontan Circulation: JACC Review Topic of the Week

The Fontan operation has resulted in significant improvement in survival of patients with single ventricle physiology. As a result, there is a growing population of individuals with Fontan physiology reaching adolescence and adulthood. Despite the improved survival, there are long-term morbidities associated with the Fontan operation. Pulmonary complications are common and may contribute to both circulatory and pulmonary insufficiency, leading ultimately to Fontan failure. These complications include restrictive lung disease, sleep abnormalities, plastic bronchitis, and cyanosis. Cyanosis post-Fontan procedure can be attributed to multiple causes including systemic to pulmonary venous collateral channels and pulmonary arteriovenous malformations. This review presents the unique cardiopulmonary interactions in the Fontan circulation. Understanding the cardiopulmonary interactions along with improved recognition and treatment of pulmonary abnormalities may improve the long-term outcomes in this growing patient population. Interventions focused on improving pulmonary function including inspiratory muscle training and endurance training have shown a promising effect post-Fontan procedure.

Practical guidance for the diagnosis and management of secondary hypogammaglobulinemia: A Work Group Report of the AAAAI Primary Immunodeficiency and Altered Immune Response Committees

Secondary hypogammaglobulinemia (SHG) is characterized by reduced immunoglobulin levels due to acquired causes of decreased antibody production or increased antibody loss. Clarification regarding whether the hypogammaglobulinemia is secondary or primary is important because this has implications for evaluation and management. Prior receipt of immunosuppressive medications and/or presence of conditions associated with SHG development, including protein loss syndromes, are histories that raise suspicion for SHG. In patients with these histories, a thorough investigation of potential etiologies of SHG reviewed in this report is needed to devise an effective treatment plan focused on removal of iatrogenic causes (eg, discontinuation of an offending drug) or treatment of the underlying condition (eg, management of nephrotic syndrome). When iatrogenic causes cannot be removed or underlying conditions cannot be reversed, therapeutic options are not clearly delineated but include heightened monitoring for clinical infections, supportive antimicrobials, and in some cases, immunoglobulin replacement therapy. This report serves to summarize the existing literature regarding immunosuppressive medications and populations (autoimmune, neurologic, hematologic/oncologic, pulmonary, posttransplant, protein-losing) associated with SHG and highlights key areas for future investigation.

The use of steroids in treating chylothorax following cardiac surgery in children: a unique perspective

BACKGROUND

Chylothorax is the accumulation of chyle fluid in the pleural space. The incidence of chylothorax is quite common post-cardiac surgeries in pediatrics especially in Fontan procedures. Although several treatment lines are known for the management of chylothorax, steroids were scarcely reported as a treatment option. We present a unique case of a 4-year-old child who underwent Fontan procedure and suffered a long-term consequence of chylothorax. The chylothorax only fully resolved after introducing corticosteroids as part of her management.

METHODS

A literature review about management of chylothorax post-cardiac surgery in children using Ovid Medline (19462021), PubMed, and google scholar was performed.

CONCLUSION

Conservative management without additional surgical intervention is adequate in most patients. Additionally, somatostatin can be used with variable success rate. However, a few cases mentioned using steroids in such cases. More research and reporting on the use of steroids in the treatment of chylothorax post-cardiac surgeries in children is needed to prove its effectivity. In this article, we describe a case of chylothorax post-Fontan procedure that supports the use of steroids.

Current Treatment Options for the Failing Fontan Circulation

The Fontan operation was introduced in 1968. For congenital malformations, where biventricular repair is unsuitable, the Fontan procedure has provided a long-term palliation strategy with improved outcomes compared to the initially developed procedures. Despite these improvements, several complications merely due to a failing Fontan circulation, including myocardial dysfunction, arrhythmias, increased pulmonary vascular resistance, protein-losing enteropathy, hepatic dysfunction, plastic bronchitis, and thrombo-embolism, may occur, thereby limiting the life-expectancy in this patient cohort. This review provides an overview of the most common complications of Fontan circulation and the currently available treatment options.

Intrahepatic Dynamic Contrast-Enhanced Magnetic Resonance Lymphangiography: Potential Imaging Signature for Protein-Losing Enteropathy in Congenital Heart Disease

Background

Protein‐losing enteropathy (PLE) is a significant cause of morbidity and mortality in congenital heart disease patients with single ventricle physiology. Intrahepatic dynamic contrast‐enhanced magnetic resonance lymphangiography (IH‐DCMRL) is a novel diagnostic technique that may be useful in characterizing pathologic abdominal lymphatic flow in the congenital heart disease population and in diagnosing PLE. The objective of this study was to characterize differences in IH‐DCMRL findings in patients with single ventricle congenital heart disease with and without PLE.

Methods and Results

This was a single‐center retrospective study of IH‐DCMRL findings and clinical data in 41 consecutive patients, 20 with PLE and 21 without PLE, with single ventricle physiology referred for lymphatic evaluation. There were 3 distinct duodenal imaging patterns by IH‐DCMRL: (1) enhancement of the duodenal wall with leakage into the lumen, (2) enhancement of the duodenal wall without leakage into the lumen, and (3) no duodenal involvement. Patients with PLE were more likely to have duodenal involvement on IH‐DCMRL than patients without PLE (P<0.001).

Conclusions

IH‐DCMRL findings of lymphatic enhancement of the duodenal wall and leakage of lymph into the duodenal lumen are associated with PLE. IH‐DCMRL is a useful new modality for characterizing pathologic abdominal lymphatic flow in PLE and might be useful as a risk‐assessment tool for PLE in at‐risk patients.

Pulmonary vascular disease in Fontan circulation-is there a rationale for pulmonary vasodilator therapies?

The Fontan circulation is a palliative concept for patients with univentricular hearts. The central veins are connected directly to the pulmonary arteries (cavo-pulmonary connection) to separate the pulmonary and the systemic circulation. There is no sub-pulmonary ventricle that generates pressure to drive blood through the pulmonary arteries. Pulmonary blood flow is determined by central venous pressure (CVP) and pulmonary vascular resistance (PVR). The capability of the Fontan circulation to compensate for alterations in PVR is limited, as CVP can only be increased within narrow ranges without adverse clinical consequences. Consequently, systemic ventricular preload and cardiac output are dependent on a healthy lung with low PVR. Failure of the Fontan circulation is relatively common. In addition to ventricular dysfunction, maladaptive pulmonary vascular remodeling resulting in increased pulmonary resistance may play a key role. The pathophysiology of the maladaptive vascular processes remains largely unclear and diagnosis of an increased PVR is challenging in Fontan circulation as accurate measurement of pulmonary arterial blood flow is difficult. In the absence of a sub-pulmonary ventricle, pulmonary artery pressure will almost never reach the threshold conventionally used to define pulmonary arterial hypertension. There is a need for markers of pulmonary vascular disease complementary to invasive hemodynamic data in Fontan patients. In order to treat or prevent failure of the Fontan circulation, pathophysiological considerations support the use of pulmonary vasodilators to augment pulmonary blood flow and systemic ventricular preload and lower CVP. However, to date the available trial data have neither yielded enough evidence to support routine use of pulmonary vasodilators in every Fontan patient nor have they been helpful in defining subgroups of patients that might benefit from such therapies. This review discusses potential pathomechanisms of pulmonary vascular disease; it summarizes the current knowledge of the effects and efficacy of pulmonary vasodilator therapy in Fontan patients and tries to outline areas of potential future research on the diagnosis and treatment of pulmonary vascular disease and Fontan failure.

Innominate Vein Turn-down Procedure for Failing Fontan Circulation

After the Fontan, systemic venous hypertension induces pathophysiologic changes in the lymphatic system that can result in complications of pleural effusion, ascites, plastic bronchitis, and protein losing enteropathy. Advances in medical therapy and novel interventional approaches have not substantially improved the poor prognosis of these complications. A more physiological approach has been developed by decompression of the thoracic duct to the lower pressure common atrium with a concomitant increase of preload. Diverting the innominate vein to the common atrium increases the transport capacity of the thoracic duct, which in most patients enters the circulation at the left subclavian-jugular vein junction. Contrary to the fenestrated Fontan circulation, in which the thoracic duct is drained into the high pressure Fontan circulation, turn down of the innominate vein to the common atrium effectively decompresses the thoracic duct to the lower pressure system with "diastolic suctioning" of lymph. Innominate vein turn-down may be considered for medical-refractory post-Fontan lymphatic complications of persistent chylothorax, plastic bronchitis, and protein losing enteropathy. Prophylactic innominate vein turn-down may also be considered at time of the Fontan operation for patients that are higher risk for lymphatic complications.

Optimized Computed Tomography Angiography Protocol for the Evaluation of Thrombus in Patients with Fontan Anatomy

The Fontan procedure is the final stage in the palliative surgical approach to patients with single-ventricle physiology. These patients have an increased risk for thromboembolic disease in the Fontan circuit, which can be evaluated by chest computed tomography angiography (CTA) in acute settings. However, false-positive results are common secondary to unusual streaming patterns in the Fontan circuit. A biphasic CTA protocol was evaluated for the capability to clearly identify structures of the Fontan circuit that are critical for the evaluation of thromboembolic disease. The study was a retrospective chart review of Fontan patients with a chest CTA scan obtained between 2011 and 2017. Two pediatric cardiologists with additional training in cardiac CT imaging independently reviewed each CTA and awarded one point for each of 5 Fontan circuit structures clearly identified resulting in a score range of 0-5. A score of 0-2 considered not capable, 3-4 partially capable, and 5 capable to clearly identify critical structures of the Fontan circuit. During the study period, 46 CTA scans were performed on 21 patients. Of the CTA scans using a biphasic protocol, 62.5% (10/16) were considered capable to clearly identify all 5 critical structures of the Fontan circuit vs 27% (8/30) of the CTA scans using a monophasic protocol (p = 0.027). Overall our results suggest that the single-site biphasic CTA protocol has greater diagnostic capability to detect the presence of Fontan thromboembolic disease when compared to the more traditional monophasic CTA protocol. Future prospective studies are needed to confirm these findings.

Reduced Parasympathetic Activity in Patients With Different Types of Congenital Heart Disease and Associations to Exercise Capacity

PURPOSE

Current research indicates an imbalance in the autonomic nervous system (ANS) pathway activities in patients with congenital heart disease (CHD). The heart rate variability (HRV) is a measure to quantify activities of the parasympathetic and sympathetic branches. This study evaluated the parasympathetic activity by means of HRV in patients with CHD, regarding diagnostic subgroups and CHD severity, and the association to exercise capacity.

METHODS

From July 2016 to August 2018, a total of 222 patients with different types of CHD (28.4 ± 10.1 yr; 44% female) received breathing-controlled HRV measurement in the supine position. Based on 130 adjacent heartbeats, the root mean square of successive differences (RMSSD), a parasympathetic activity surrogate was estimated and log-transformed. Additionally, all patients underwent a cardiopulmonary exercise test. For comparison, a control group (CG) of 57 (29.0 ± 7.1 yr; 61% female) healthy volunteers was recruited.

RESULTS

Patients with CHD exhibited reduced parasympathetic activity in comparison to the CG (lnRMSSD CHD: 3.55 ± 0.57 ms vs CG: 3.93 ± 0.55 ms; P < .001), with the lowest parasympathetic activity in patients with Fontan circulation (3.07 ± 0.54 ms; P < .001). Complex CHD (3.40 ± 0.54 ms) had worse values compared with patients with simple (3.87 ± 0.55 ms; P < .001) and moderate severity (3.74 ± 0.54 ms; P < .001). Better parasympathetic activity in CHD patients was associated with increased exercise capacity (r = 0.322; P < .001).

CONCLUSIONS

Impaired parasympathetic activity suggests limited function of the ANS in patients with CHD. Further studies should focus on the association of exercise capacity and ANS to possibly improve parasympathetic activity and functional outcomes.

Comparison of pleural effusion between fenestrated and nonfenestrated extracardiac Fontan: A prospective randomized study

BACKGROUND

Fenestration of the baffle/conduit is believed to reduce pleural effusion following the Fontan operation. However, equivocal results have been observed with or without fenestration. This study aims to evaluate the efficacy of fenestration on the amount and duration of pleural effusion following the Fontan operation.

METHODS

About 40 patients undergoing extracardiac Fontan (ECF) were randomized into two groups: one with fenestration (ECF-F; n = 20) or without fenestration (ECF-NF; n = 20). Primary outcome was the amount and duration of pleural effusions. Secondary outcomes were time to removal of the chest tubes, hospital stay, and readmission to the hospital because of recurrent pleural within 30 days of the operation.

RESULTS

Mean age was 11.5 ± 5.07 (range, 8.7-13.5) years in the ECF-F group and 13.6 ± 0.4 years (range, 10.5-15.5) in the (ECF-NF) group. The total drain output was 7.89 mL/kg/d in ECF-NF compared with 6.9 mL/kg/d in the ECF-group (P = .14). Time for removal of pleural tubes was 14.6 ± 0.95 days in the ECF-NF group compared with 11.6 ± days in the ECF-F group. Total duration of hospital stay was higher but not significant in the ECF-NF group compared with the ECF-F group. Two patients in ECF-NF required readmission to the hospital within 30 days following discharge, while there were no readmissions in the ECF-F group.

CONCLUSION

Contrary to the literature, the creation of a fenestration in the ECF circuit was not clearly associated with a reduction in the amount and duration of pleural effusion compared with a non-fenestrated Fontan. These findings may be debatable in high risks versus low risk candidates. However in the present study, in a low risk canditates undergoing the Fontan operation, the daily amount of pleural drainage was no different. Larger studies are needed to confirm these findings.

CHAPLE syndrome uncovers the primary role of complement in a familial form of Waldmann's disease

Primary intestinal lymphangiectasia (PIL) or Waldmann's disease was described in 1961 as an important cause of protein-losing enteropathy (PLE). PIL can be the sole finding in rare individuals or occur as part of a multisystemic genetic syndrome. Although genetic etiologies of many lymphatic dysplasia syndromes associated with PIL have been identified, the pathogenesis of isolated PIL (with no associated syndromic features) remains unknown. Familial cases and occurrence at birth suggest genetic etiologies in certain cases. Recently, CD55 deficiency with hyperactivation of complement, angiopathic thrombosis, and PLE (the CHAPLE syndrome) has been identified as a monogenic form of PIL. Surprisingly, loss of CD55, a key regulator of complement system leads to a predominantly gut condition. Similarly to other complement disorders, namely paroxysmal nocturnal and hemoglobinuria (PNH) and atypical hemolytic uremic syndrome (aHUS), CHAPLE disease involves pathogenic cross-activation of the coagulation system, predisposing individuals to severe thrombosis. The observation that complement system is overly active in CHAPLE disease introduced a novel concept into the management of PLE; anti-complement therapy. While CD55 deficiency constitutes a treatable subgroup in the larger pool of patients with isolated PIL, the etiology remains to be identified in the remaining patients with intact CD55.

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).

Fontan-associated protein-losing enteropathy and post‒heart transplant outcomes: A multicenter study

BACKGROUND

The influence of Fontan-associated protein-losing enteropathy's (PLE) severity, duration, and treatment on heart transplant (HTx) outcomes is unknown. We hypothesized that long-standing PLE and PLE requiring more intensive therapy are associated with increased post-HTx mortality.

METHODS

This 12-center, retrospective cohort study of post-Fontan patients with PLE referred for HTx from 2003 to 2015 involved collection of demographic, medical, surgical, and catheterization data, as well as PLE-specific data, including duration of disease, intensity/details of treatment, hospitalizations, and complications. Factors associated with waitlist and post-HTx outcomes and PLE resolution were sought.

RESULTS

Eighty patients (median of 5 per center) were referred for HTx evaluation. Of 68 patients listed for HTx, 8 were removed due to deterioration, 4 died waiting, and 4 remain listed. In 52 patients undergoing HTx, post-HTx 1-month survival was 92% and 1-year survival was 83%. PLE-specific factors, including duration of PLE pre-HTx, pre-HTx hospitalizations, need for/frequency of albumin replacement, PLE therapies, and growth parameters had no association with post-HTx mortality. Immunosuppressant regimen was associated with mortality; standard mycophenolate mofetil immunotherapy was used in 95% of survivors compared with only 44% of non-survivors (p = 0.03). Rejection (53%) and infection (42%) post-HTx were common, but not associated with PLE-specific factors. PLE resolved completely in all but 1 HTx survivor at a median of 1 month (interquartile range 1 to 3 months); resolution was not affected by PLE-specific factors.

CONCLUSIONS

PLE severity, duration, and treatment do not influence post-HTx outcome, but immunosuppressive regimen may have an impact on survival. PLE resolves in nearly all survivors.

Prevalence of non-cardiovascular findings on CT angiography in children with congenital heart disease

BACKGROUND

CT angiography is gaining broader acceptance in the evaluation of children with known or suspected congenital heart disease. These studies include non-cardiovascular structures such as the mediastinum, lung parenchyma and upper abdominal organs. It is important to inspect all these structures for potential abnormalities that might be clinically important and, in some cases, may impact care plans.

OBJECTIVE

To determine the prevalence of non-cardiovascular findings in CT angiography of children with congenital heart disease.

MATERIALS AND METHODS

During 28 months, 300 consecutive children (170 males; mean age: 7.1 years, age range: 6 h-26 years), referred from a tertiary pediatric cardiology center, underwent clinically indicated CT angiography to evaluate known or suspected congenital heart disease. Slightly more than half (n = 169) of the patients were postoperative or post-intervention. Examinations were retrospectively reviewed, and non-cardiovascular findings were recorded and tabulated by organ system, congenital heart disease and operative procedure in conjunction with outcomes from medical charts.

RESULTS

Non-cardiovascular findings were identified in 83% (n = 250 / 300) of the studies for a total of 857 findings. In 221 patients (n = 73.7% of 300) a total of 813 non-cardiovascular findings were clinically significant, while in 9.7% (n = 29 / 300) of patients, 5.1% (n = 44 / 857) of the findings were nonsignificant. In 38.3% (n = 115 / 300) of patients with significant non-cardiovascular pathology, the findings were unexpected and directly impacted patient care plans. Commonly involved organs with non-cardiovascular findings were the lungs with 280 non-cardiovascular findings in 176 / 300 (58.7%) of patients, the airway with 139 non-cardiovascular findings in 103 / 300 (34.3%) of patients and the liver with 108 non-cardiovascular findings in 72 / 300 (24.0%) of patients. Syndromic associations were noted in 22% (n = 66 / 300) of the patients.

CONCLUSION

Non-cardiovascular findings are common in children with congenital heart disease who undergo CT angiography. Based upon our study population, if a child with congenital heart disease has a CT angiography, five out of six will have non-cardiovascular findings, while nearly three out of four (73.7%; 221 / 300) will have significant non-cardiovascular findings. Close attention to the non-cardiovascular structures in children with congenital heart disease presenting for a CT angiography is recommended as in nearly 40% of these children, findings were unexpected and directly altered patient care.

Hypoplastic left heart syndrome: a review

BACKGROUND

Hypoplastic left heart syndrome (HLHS) is an etiologically multifactorial congenital heart disease affecting one in 5,000 newborns. Thirty years ago there were no treatment options for this pathology and the natural course of the disease led to death, usually within the first weeks of life. Recently surgical palliative techniques have been developed allowing for a five-year survival in more than half the cases.

MATERIALS AND METHODS

We reviewed literature available on HLHS, specifically its anatomy, embryology and pathophysiology, and treatment. The Pubmed and ClinicalKey databases were searched using the key words hypoplastic left heart syndrome, foetal aortic valvuloplasty, foetal septoplasty, Norwood procedure, bidirectional Glenn procedure, Fontan procedure, hybrid procedure. The relevant literature was reviewed and included in the article. We reported a case from Children's Clinical University Hospital, Riga, to illustrate treatment tactics in Latvia.

RESULTS

There are three possible directions for therapy in newborns with HLHS: orthotopic heart transplantation, staged surgical palliation and palliative non-surgical treatment or comfort care. Another treatment mode - foetal therapy - has arisen. Staged palliation and full Fontan circulation is a temporary solution, however, the only means for survival until heart transplantation. Fifty to 70% of patients who have gone through all three stages of palliation live to the age of five years.

CONCLUSIONS

The superior mode of treatment is not yet clear and the management must be based on each individual case, the experience of each clinic, as well as the financial aspects and will of the patient's parents.

Creating a Fontan fenestration in a child with dextrocardia and interrupted inferior vena cava

Plastic bronchitis is a rare life-threatening complication of the Fontan operation. Transcatheter Fontan fenestration can ameliorate symptoms by decompressing elevated venous pressures. Transcatheter creation of a fenestration can be technically challenging in cases with complex venous anatomy. We report a case of a 5-year-old boy with heterotaxy, dextrocardia with unbalanced atrioventricular canal (AVC), atrial and visceral situs inversus, left-sided superior vena cava (SVC), and left-sided interrupted inferior vena cava (IVC) with azygos continuation. With few modifications to the equipment, a successful Fontan fenestration with stent implantation was performed via transjugular approach. At 2-year follow-up, his symptoms of plastic bronchitis improved significantly.

A multifaceted approach to the management of plastic bronchitis after cavopulmonary palliation

BACKGROUND

Plastic bronchitis is a rare, potentially life-threatening complication after Fontan operation. Hemodynamic alterations (elevated central venous pressure and low cardiac output) likely contribute to the formation of tracheobronchial casts composed of inflammatory debris, mucin, and fibrin. Pathologic studies of cast composition support medical treatment with fibrinolytics such as inhaled tissue plasminogen activator (t-PA).

METHODS

This was a retrospective case series of medical, surgical, and catheter-based treatment of patients with plastic bronchitis after cavopulmonary palliation.

RESULTS

Included were 14 patients (86% male, 93% white). Median age at Fontan operation was 2.7 years (range, 1.2 to 4.1 years), with median interval to plastic bronchitis presentation of 1.5 years (range, 9 days to 15.4 years). Cast composition was available for 11 patients (79%) and included fibrin deposits in 7. All patients were treated with pulmonary vasodilators, and 13 (93%) were treated with inhaled t-PA. Hemodynamically significant lesions in the Fontan pathway were addressed by catheter-based (n=9) and surgical (n=3) interventions. Three patients (21%) underwent heart transplantation. Median follow-up was 2.7 years (range, 0.6 to 8.7 years). Symptoms improved, such that 6 of 13 patients (46%) were weaned off t-PA. Rare or episodic casts are successfully managed with outpatient t-PA in most of the other patients. Of the 3 patients who underwent heart transplant, 2 are asymptomatic and 1 has recurrent casts in the setting of elevated filling pressures and rejection.

CONCLUSIONS

A systematic step-wise algorithm that includes optimization of hemodynamics, aggressive pulmonary vasodilation, and inhaled t-PA is an effective treatment strategy for patients with plastic bronchitis after cavopulmonary connection.

MR assessment of abdominal circulation in Fontan physiology

The Fontan operation allows for longer survival of those born with functionally single ventricle physiology. Although it effectively eliminates cyanosis, increased systemic venous pressure is an unavoidable consequence and low cardiac output is frequent. The abdomen is particularly vulnerable to these alterations in hemodynamics because the hepatic blood flow consists predominantly of portal venous flow, which relies on a low pressure gradient between the portal and hepatic veins. Therefore, any subtle increase in systemic venous pressure will adversely affect the hemodynamic balance of the liver as well as the intestine. As the clinical manifestations and routine laboratory findings of abdominal complications can lag behind the hemodynamic and pathologic changes in the abdominal organs, regular imaging surveillance is critical. Magnetic resonance (MR) provides excellent visualization of both cardiovascular and abdominal systems. It provides robust anatomic and hemodynamic data which can be used for timely implementation of treatment options. In this review paper, we discuss the pathogenesis and MR findings of abdominal complications following the Fontan operation. Specifically we explore the utility of phase-contrast MR for assessment of the abdominal circulation in children following the Fontan palliation.

Immunophenotyping and protein profiling of Fontan-associated plastic bronchitis airway casts

RATIONALE

Plastic bronchitis (PB) is a rare and deadly condition that is characterized by the formation of airway casts. It most frequently occurs in children with underlying congenital heart disease that has been surgically palliated by the Fontan procedure. The Fontan circulation results in above-normal central venous pressure, and it has been hypothesized that the formation of airway casts is due to lymph leak. Knowledge of plastic bronchitis pathogenesis is poor and stems mostly from published case reports.

OBJECTIVES

To garner information about cast pathogenesis by characterizing inflammatory cell phenotypes in existing formalin-preserved, paraffin-embedded samples and generating protein and cytokine-chemokine profiles of airway cast homogenates.

METHODS

We used immunofluorescence confocal microscopy, state-of-the-science proteomics, and a cytokine array assay to immunophenotype cellular content and to generate protein and cytokine profiles of plastic bronchitis airway casts, respectively.

MEASUREMENTS AND MAIN RESULTS

Neutrophils, eosinophils, macrophages, and B lymphocytes were identified in cast samples; there were notably fewer T lymphocytes. Fibrin(ogen) was an abundant protein in the cast proteome. Histone H4 was also abundant, and immunofluorescence microscopy demonstrated it to be mostly extracellular. The cytokine profile of plastic bronchitis casts was proinflammatory.

CONCLUSIONS

Plastic bronchitis airway casts from children with Fontan physiology are composed of fibrin and are cellular and inflammatory in nature, providing evidence that their formation cannot be explained simply by lymph leak into the airways. Consequences of cellular necrosis including extracellular histones and the apparent low number of T cells indicate that a derangement in inflammation resolution likely contributes to cast formation.

Laparoscopic antireflux surgery in infants with single ventricle physiology: a review

Laparoscopic fundoplication and gastrostomy tube placement have grown in popularity within the pediatric population for treatment of gastroesophageal reflux disease and failure to thrive, respectively. One population that has an increased need for gastric surgery in infancy is patients with congenital heart defects, especially those with "single ventricle physiology." The most common defect included in this population is hypoplastic left heart syndrome (HLHS). Because of the abnormal physiology present in this condition, there are concerns with regard to the use of laparoscopic procedures for gastric surgery in patients treated with a three-staged reconstruction. We review the staged reconstruction of infants with HLHS, address safety concerns of interstage noncardiac procedures on this patient population, and review the current literature regarding outcomes of laparoscopic gastric surgery on patients with single ventricle physiology.

Pharmacotherapy challenges of Fontan-associated plastic bronchitis: a rare pediatric disease

Pediatric pharmacotherapy is often challenging due to the paucity of available clinical data on the safety and efficacy of drugs that are commonly used in children. This quandary is even more prevalent in children with rare diseases. Although extrapolations for dosing and administration are often made from available adult data with similar disease states, this translation becomes even more problematic in rare pediatric diseases. Understanding of rare disease pathophysiology is typically poor, and few, if any, effective therapies have been studied and identified. One condition that illustrates these issues is plastic bronchitis, a rare, most often pediatric disease that is characterized by the production of obstructive bronchial airway casts. This illness primarily occurs in children with congenital heart disease, often after palliative surgery. Plastic bronchitis is a highly clinically relevant and therapeutically challenging problem with a high mortality rate, and, a generally accepted effective pharmacotherapy regimen has yet to be identified. Furthermore, the disease is ill defined, which makes timely identification and treatment of children with plastic bronchitis difficult. The pharmacotherapies currently used to manage this disease are largely anecdotal and vary between the use of macrolide antibiotics, mucolytics, bronchodilators, and inhaled fibrinolytics in a myriad of combinations. The purpose of this review is 2-fold: first, to highlight the dilemma of treating plastic bronchitis, and second, to bring attention to the continuing need for studies of drug therapies used in children so safe and effective drug regimens can be established, particularly for rare diseases.

Perioperative management of shock in two fontan patients with plastic bronchitis

Plastic bronchitis is potentially a life-threatening complication of long-standing surgically palliated single ventricle congenital heart disease. Patients can present with hypoxia requiring urgent bronchoscopy for removal of bronchial casts. Perioperative care for these patients is challenging and anesthesia is associated with significant cardiac risk. As more surgically corrected single ventricle patients survive to adulthood, these patients are expected to present more frequently. This report details the perioperative management of 2 Fontan patients with hypoxia and significant plastic bronchitis disease burden.

Demographic characteristics and estimated prevalence of Fontan-associated plastic bronchitis

Plastic bronchitis (PB) is a poorly understood disease that can complicate any underlying pulmonary disease. However, it appears to most often occur in patients with surgically palliated congenital heart disease, particularly after the Fontan procedure. Few data exist about the prevalence and etiology of PB in this population. In an effort to establish data about prevalence, we conducted a retrospective study of an existing Fontan surgery database (n = 654) comprised of data, including sex, age at date of surgery, alive/dead status, New York Heart Association classification at last follow-up, right-ventricular end-diastolic pressure and pulmonary artery pressure before Fontan surgery, and the presence of a Fontan fenestration. An initial medical record review of 173 patients in the database who were followed at the University of Michigan identified seven patients with PB resulting in an estimated prevalence of 4 %. Subsequently, 14 % of 211 surveyed patients reported that they presently expectorate mucus or fibrin plugs (casts). Demographic and clinical variables did not differ between patients with or without possible PB. Collectively, these findings suggest that Fontan patients presently with PB may range from 4 to 14 %, indicating potential under-diagnosis of the disease. There were no remarkable physical or hemodynamic indicators that differentiated patients with or without possible PB. These data also highlight the need for more elaborate, prospective studies to improve our understanding of PB pathogenesis so that more definitive diagnostic criteria for this devastating disease can be established and its prevalence more accurately determined.

Orthotopic heart transplantation in patients with univentricular physiology

Parallel advancements in surgical technique, preoperative and postoperative care, as well as a better understanding of physiology in patients with duct-dependent pulmonary or systemic circulation and a functional single ventricle, have led to superb results in staged palliation of most complex congenital heart disease (CHD) [1]. The Fontan procedure and its technical modifications have resulted in markedly improved outcomes of patients with single ventricle anatomy [2,3,4]. The improved early survival has led to an exponential increase of the proportion of Fontan patients surviving long into adolescence and young adulthood [5]. Improved early and late survival has not yet abolished late mortality secondary to myocardial failure, therefore increasing the referrals for cardiac transplantation [6]. Interstage attrition [7] is moreover expected in staged palliation towards completion of a Fontan-type circulation, while Fontan failure represents a growing indication for heart transplantation [8]. Heart transplantation has therefore become the potential “fourth stage” [9] or a possible alternative to a high-risk Fontan operation [10] in a strategy of staged palliation for single ventricle physiology. Heart transplant barely accounts for 16% of pediatric solid organ transplants [11]. The thirteenth official pediatric heart transplantation report- 2010 [11] indicates that pediatric recipients received only 12.5% of the total reported heart transplants worldwide. Congenital heart disease is not only the most common recipient diagnosis, but also the most powerful predictor of 1-year mortality after OHT. Results of orthotopic heart transplantations (OHT) for failing single ventricle physiology are mixed. Some authors advocate excellent early and mid-term survival after OHT for failing Fontan [9], while others suggest that rescue-OHT after failing Fontan seems unwarranted [10]. Moreover, OHT outcome appears to be different according to the surgical staging towards the Fontan operation and surgical technique of Fontan completion [12].

The focus of this report is a complete review of the recent literature on OHT for failing single ventricles, outlining the clinical issues affecting Fontan failure, OHT listing and OHT outcome. These data are endorsed reporting our experience with OHT for failing single ventricle physiology in recent years.

Health considerations for children with congenital heart disease in school: part 1

School participation for children with congenital heart disease (CHD) can be challenging. Despite advances in treatment that have increased survival to adulthood and decreased morbidity, concerns remain about their health and safety in the school environment. This article, the first in a two-part series, provides an overview of the health issues involving school-age children with CHD. School nurses are in a unique position to advocate for the child's health care needs in the school setting, facilitate communication with the health care team, educate school personnel, and participate in the individualized educational planning process.

Children with protein-losing enteropathy after the Fontan operation are at risk for abnormal bone mineral density

Protein-losing enteropathy (PLE) is a rare but potentially devastating complication of single-ventricle physiology after the Fontan operation. Although abnormal bone mineral density (BMD) is a known complication of chronic disease and congenital heart disease, no reports have described BMD in patients with PLE. This study investigated a cross-sectional sample of children and young adults with a confirmed diagnosis of PLE. Serum levels of 25(OH)D, calcium, total protein, and albumin were recorded from the first outpatient encounter with each subject. Corrected calcium (cCa) was calculated from the serum calcium and albumin levels. Dual-energy X-ray absorptiometry (DXA) was used to measure BMD, and z-scores were generated using appropriate software. DXA results were available for 12 patients (eight males and four females). The age at DXA ranged from 7.2 to 25.2 years. The mean z-score was -1.73 standard deviation (SD) for the entire cohort, with 42 % z-scores below -2 SDs. Serum 25(OH)D levels were abnormal in 58 % of the patients. There was a positive correlation between cCa and DXA z-score and a negative correlation between total protein and DXA z-score. Patients receiving corticosteroid therapy had a significantly lower DXA z-score than those not receiving corticosteroids (-3.15 vs. -0.31; p = 0.02). Children with PLE are at risk for abnormal BMD compared with age- and sex-matched control subjects. In the study cohort, corticosteroid exposure, a marker of disease severity, appeared to be associated with decreased BMD. Routine bone health screening is warranted for children with PLE, particularly those receiving corticosteroid therapy.

Management of plastic bronchitis with topical tissue-type plasminogen activator

Plastic bronchitis or cast bronchitis is a rare disease of unclear etiology characterized by formation of airway casts that can lead to life-threatening airway obstruction. There is currently limited data regarding optimal treatment of plastic bronchitis. Several therapies have been suggested, but recurrences are common and mortality remains high. We report the case of a 6-year-old boy with refractory eosinophilic bronchial casts, unresponsive to low-dose systemic corticosteroids, inhaled corticosteroids, azithromycin, and dornase alfa, who was treated successfully and safely with direct instillation of tissue-type plasminogen activator (tPA) to the obstructing casts during flexible bronchoscopy and inhaled tPA. Our case illustrates that the current therapy for plastic bronchitis remains inadequate. To our knowledge, this case is the first to show that direct instillation of tPA can be used safely for treatment of this disease. The use of tPA via direct administration into the airways during bronchoscopy and via a nebulizer appeared to be a safe and effective therapy for plastic bronchitis and should be considered early in the course of the disease to prevent complications of severe airway obstruction.

Barotrauma as aetiological cascade of fatal intrapulmonary plastic bronchitis in a post-Fontan child

The role of barotrauma in the exaggeration of plastic bronchitis after Fontan circulation has yet to be examined. We aim to describe a case of a 4-year old post-Fontan circulation girl where barotrauma suffered during commercial air travel played a role in the aetiological cascade of plastic bronchitis.

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.

Long term respiratory outcomes of congenital diaphragmatic hernia, esophageal atresia, and cardiovascular anomalies

Intrathoracic congenital malformations may be associated with long-term pulmonary morbidity. This certainly is the case for congenital diaphragmatic hernia, esophageal atresia and cardiac and aortic arch abnormalities. These conditions have variable degrees of impaired development of both the airways and lung vasculature, with a postnatal impact on lung function and bronchial reactivity. Pulmonary complications are themselves frequently associated to non-pulmonary morbidities, including gastrointestinal and orthopaedic complications. These are best recognized in a structured multidisciplinary follow-up clinic so that they can be actively managed.

Prospective, longitudinal study of plastic bronchitis cast pathology and responsiveness to tissue plasminogen activator

Plastic bronchitis (PB) is a rare disease that often occurs in patients with congenital heart disease (CHD) who have undergone staged single-ventricle palliation. It is characterized by the formation of rubbery "casts" in the airways. PB treatment frequently includes inhaled tissue plasminogen activator (tPA). However, the efficacy of tPA to reduce cast burden is unknown. This is further complicated by our lack of knowledge of cast composition. We obtained spontaneously expectorated PB casts from children (n = 4) with CHD and one adult patient with idiopathic PB. Pathological assessment was made from paraffin-preserved samples. Casts were treated with phosphate-buffered saline (PBS) or tPA. Cast response to tPA was assessed by changes in cast weight and the production of fibrin D-dimer. Independent of dose, tPA reduced cast weight compared with PBS-treatment (P = 0.001) and increased D-dimer levels. Histological staining showed that PB casts from all patients were composed of fibrin and contained notable numbers of lymphocytes. Cast composition did not change over time. Collectively, these data support that in our PB patients, casts are composed of fibrin and are responsive to tPA treatment. This makes inhaled tPA a potentially viable option for symptomatic relief of PB while we work to unravel the complexity of PB pathogenesis.