Protein-losing Enteropathy after the Fontan Operation: Associations and Predictors of Clinical Outcome

Fontan-Associated Anatomical Variants and Hepatic Fibrosis

OBJECTIVE

We hypothesized that a relationship between post-Fontan hepatic fibrosis and anatomical variants might exist.

METHODS

Attempting to limit confounding variables, we analyzed data from living, stable, post-extracardiac Fontan patients who underwent cardiac catheterization and transvenous hepatic biopsy procedures between March 2012 and June 2020.

RESULTS

We identified 120 patients who met the inclusion criteria. Of the 120, 35 (29%) had pulmonary artery stents. For the 35 with pulmonary artery stents, the average total fibrosis score was 3.2 ± 1.9 and the fibrosis progression rate was 0.36 ± 0.33, and for those with no pulmonary artery stents, the total fibrosis score was 2.6 ± 1.8 and the fibrosis progression rate was 0.27 ± 0.33 (P = .13 and P = .11, respectively). Of the 120, 65 had functional univentricles of right ventricular type. Of these 65, 27 had pulmonary artery stents. For the 27 with pulmonary artery stents, the average total fibrosis score was 3.4 ± 1.8 and the average fibrosis progression rate was 0.39 ± 0.30, and for the 38 without pulmonary artery stents, the average fibrosis score was 2.3 ± 1.5 and the average fibrosis progression rate was 0.23 ± 0.21 (P = .01 for comparison of both values).

CONCLUSIONS

This study's findings suggest that a post-extracardiac Fontan with a functional univentricle of right ventricular type plus a pulmonary artery stent may have more advanced liver pathology than those without a pulmonary artery stent at similar Fontan duration years and ages at liver biopsy.

The Glenn procedure: Clinical outcomes in patients with congenital heart disease in pakistan

Objectives:

Congenital heart defects (CHDs) affect more than 40,000 children annually in Pakistan. Approximately 80% of patients require at least one surgical intervention to achieve a complete or palliative cardiac repair. The Glenn shunt, a palliative procedure is established between superior vena cava (SVC) and the right pulmonary artery to provide an anastomosis offering minimal risk to patients with univentricular heart disease. The aim of this study was to assess the clinical outcomes of the Glenn shunt procedure in patients with complex congenital heart diseases in a developing country like Pakistan.

Materials and Methods:

A retrospective chart review was conducted on patients who underwent a bidirectional Glenn shunt procedure from July 2006 to June 2017. Data were collected on a structured questionnaire and analyses performed on SPSS version 22. Frequencies and percentages were computed for categorical variables while mean and standard deviation for continuous variables where appropriate.

Results:

A total of 79 patients underwent the Glenn shunt procedures. The median age was 1.9 years and 54.5% were male. Tricuspid atresia was the primary diagnosis in 30.4% of the patients. Common morbidities included arrhythmias (6.3%), pleural effusion (8.9%), wound infection (3.8%), pneumonia (2.5%), and seizures (3.8%); reopening was required in 2.5% of the patients and 8.8% were readmitted within 30 days of index operation. There were three (3.8%) deaths in total.

Conclusions:

Bidirectional Glenn shunt procedure can be performed safely in patients with ideal characteristics as the first stage palliation and has favorable results with acceptable rate of complications.

Impact of protein-losing enteropathy in children who underwent the Fontan operation

Previous reports have identified risk factors associated with development of post-Fontan protein-losing enteropathy. Less is known about the economic impact and resource utilisation required for post-Fontan protein-losing enteropathy in the current era. We conducted a single-centre retrospective study to assess the impact of post-Fontan protein-losing enteropathy on transplant-free survival. We also described resource utilisation and treatment variations among post-Fontan protein-losing enteropathy patients. Children who received care at our centre between 2009 and 2017 after the Fontan surgery were eligible. Initial admissions for the Fontan operative procedure were excluded. Demographics, hospital admissions, resource utilisation, medications and charges were reviewed. Patients were divided into two groups based on the presence of post-Fontan protein-losing enteropathy. Of the 343 patients screened, 147 met the eligibility criteria. Of these, 28 (19%) developed protein-losing enteropathy. After adjusting for follow-up duration, the protein-losing enteropathy group had higher number of encounters (2.15 ± 2.16 versus 1.47 ± 2.56, p 0.002), hospital length of stay (days) (25 ± 51.3 versus 11.4 ± 41.7, p < 0.0001) and total charges (2018US$) (388,489 ± 759,859 versus 202,725 ± 1,076,625, p < 0.0001). Encounters for patients with protein-losing enteropathy utilised more therapies. Among those with protein-losing enteropathy, use of digoxin was associated with slightly decreased odds for mortality and/or transplant (0.95, confidence interval 0.90-0.99, p 0.021). The 10-year transplant-free survival for patients with/without protein-losing enteropathy was 65.7/97.3% (p 0.002), respectively. Post-Fontan protein-losing enteropathy is associated with reduced 10-year transplant-free survival, higher resource utilisation, charges and medication use compared with the non-protein-losing enteropathy group. Practice variation among post-Fontan protein-losing-enteropathy patients is common. Further larger studies are needed to assess the impact of standardisation on the well-being of children with post-Fontan protein-losing enteropathy.

Longitudinal changes in echocardiographic measures of ventricular function after Fontan operation

BACKGROUND

While numerous indices have been developed in an attempt to quantify ventricular function in patients with single ventricle heart disease after Fontan, there are little data on how these parameters change over time.

METHODS

A retrospective observational study was performed of individuals who underwent Fontan operation at Children's Hospital of Philadelphia (CHOP) in 2006 and 2007. Measurements of fractional area change (FAC), tricuspid annular planar systolic excursion (TAPSE), myocardial performance index (MPI), systolic to diastolic (s/d) ratio, and myocardial strain and strain rate were made offline. A composite outcome of protein-losing enteropathy (PLE), plastic bronchitis, transplant, or death was created, and change in function was compared between those who did and those who did not meet the outcome.

RESULTS

There were 312 echocardiograms from 40 unique patients (75% male, 55% dominant right ventricle). The aggregate mean values for most assessed parameters were worse than what would be expected for a healthy age-matched population. The global longitudinal strain rate increased (worsened) by 0.014 (1/s) per year (P = .02), and the global circumferential strain rate increased (worsened) by 0.011 (1/s) per year (P = .01). There was no difference in the rate of change of ventricular function in the 6 patients who met the composite endpoint vs those who did not.

CONCLUSION

This study demonstrates that global longitudinal strain rate and global circumferential strain rate decrease over 10 years following Fontan operation. These measures of ventricular performance may be early signs of cardiac dysfunction that predate more obvious echocardiographic signs of deterioration.

The Rate of Hepatic Fibrosis Progression in Patients Post-Fontan

This investigation analyzed the rate of hepatic fibrosis progression in post-Fontan patients that underwent hepatic biopsy. The study cohort comprised post-Fontan patients that underwent cardiac catheterization and transvenous liver biopsy between March 2012 and September 2019. We identified 126 patients that met inclusion criteria. Of the 126, 27 (21%) had a lateral tunnel Fontan, and 99 (79%) had an extracardiac Fontan. For the 27 lateral tunnel Fontan patients, age at Fontan was 4 ± 2 years, and for the 99 extracardiac Fontan patients age at Fontan was 4 ± 2 years (p = 0.98). For the 27 lateral tunnel Fontan patients, the average total fibrosis score was 3.0 ± 1.5; and for the 99 extracardiac Fontan patients, the average total fibrosis was 2.7 ± 1.7 (p = 0.48). For the lateral tunnel Fontan patients, the average Fontan duration was 20 ± 6 years; and for the 99 extracardiac Fontan patients, the average Fontan duration was 11 ± 5 years (p < 0.001). For the 27 lateral tunnel Fontan patients, the average rate of fibrosis progression was 0.16 ± 0.10 total fibrosis score/year; and for the 99 extracardiac Fontan patients, the average rate of fibrosis progression was 0.30 ± 0.23 total fibrosis score/year (p < 0.001). In conclusion, our findings suggest that those with extracardiac Fontans have a faster rate of hepatic fibrosis progression than those with lateral tunnel Fontans. More extensive or multi-institutional studies will be needed to confirm these findings and define the clinical significance of discrepant rates of hepatic fibrosis in post-Fontan patients.

Surveillance and screening practices of New England congenital cardiologists for patients after the Fontan operation

INTRODUCTION

Surveillance and management guidelines for Fontan patients are lacking due to the paucity of evidence in the literature of screening efficacy on outcome measures.

METHODS

The Fontan Working Group within the New England Congenital Cardiology Association designed an electronic survey to assess surveillance practices for patients with Fontan procedures among New England congenital cardiologists and to explore variability in screening low-risk vs high-risk Fontan patients across regional programs.

RESULTS

Fifty-six cardiologists representing 12 regional programs responded to the survey, comprising ~40% of the total New England congenital cardiac physicians. The majority of desired testing and consultation was available within 50 miles of the patient's home institution with some limitations of cardiac catheterization and cardiac magnetic resonance imaging availability. Surveillance and screening were less frequent in low-risk Fontan patients compared to high-risk Fontan patients. Counseling practices were similar for both low-risk and high-risk Fontan patients. Aspirin monotherapy was recommended by 82% of providers for low-risk Fontan patients, while anticoagulation regimens were more varied for the high-risk population. Practitioners with ≤15 years of experience were more likely to provide quality of life testing in both low-risk and high-risk Fontan patients. There were no other major differences in testing frequencies by years of practice, quaternary vs nonquaternary care facility, or the number of Fontan patients in a practice.

CONCLUSION

This survey provides insight into regional practices of screening and surveillance of Fontan patients. These data may be used to design future research studies and evidence-based guidelines to streamline the approach to manage these complex patients.

Transplantation in the single ventricle population

The single ventricle patient population comprises the most complex cohort presenting to the cardiac transplant team, in terms of demographics, anatomic substrate, and unique physiology. It is also the most rapidly growing diagnostic group presenting for heart transplantation. In this manuscript, we aim to describe the changing landscape of transplantation in single ventricle conditions through reflection on our own institution's practice and experience, alongside contemporary literature review. Single ventricle patients are heterogeneous in terms of age, anatomic diagnosis and physiology according to surgical stage of repair. Progress in surgical palliative strategies has impacted upon the present composition of the population, with growing numbers of hypoplastic left heart syndrome patients and those with late physiology failure following Fontan completion. Multiple prior surgeries, immunological sensitivity and multi-organ involvement impart high peri-operative risk but can be mitigated in part by careful pre-operative planning by a dedicated multi-disciplinary team addressing issues such as planning of concurrent reconstructive surgery, minimizing the post-operative effect of collaterals, timely harvesting, oversizing of donor organs to minimize graft failure, and strategies to address anticipated post-operative elevation in pulmonary vascular resistance. Determining optimal timing for transplant in these patients remains unclear, but understanding the risk of alternative surgical options can help guide decision making with regards to listing.

Diverse multi-organ histopathologic changes in a failed Fontan patient

We report multi-organ histopathological changes in a patient with protein-losing enteropathy (PLE) over 12 years after Fontan operation. A 14-year-old boy with right isomerism heart and single ventricle had undergone Fontan procedure at 19 months of age, and PLE was diagnosed at 28 months. He had several episodes of intestinal bleeding and pre-renal failure with elevated creatine, and eventually died of pneumonia. The intrapulmonary small arteries showed medial and intimal thickening resembling pulmonary hypertension. No major ulcerative lesions were found in the small or large intestines. Dilated lymph ducts, one of the characteristic features of PLE, were not seen in mucosal and submucosal areas. Liver cirrhosis was obvious despite little increase in liver enzymes. Histological changes in bilateral kidneys were subtle despite repeated episodes of renal failure. Thus, there may be significant discrepancies between clinical manifestations and multi-organ histological changes in failed Fontan patients.

Secondary Combined Immunodeficiency in Pediatric Patients after the Fontan Operation: Three Case Reports

The Fontan operation or total cavopulmonal connection (TCPC) is a palliative surgical correction of rare and complex inborn cardiac malformations that are characterized by univentricular circulation. Protein-losing enteropathy (PLE) develops in 4-13% of patients after the Fontan procedure. Fontan-related PLE leads to secondary combined immunodeficiency marked by hypogammaglobulinemia and predominantly CD4+ lymphocytopenia. Here, we present 3 case reports of patients with secondary immunodeficiency after the Fontan operation. The severity of hypogammaglobulinemia correlated with the nature of the infectious complications; however, clinical manifestations of T cell deficiency such as severe viral or opportunistic infections were not observed. The clinical consequences of the secondary combined immunodeficiency were modified by immunoglobulin replacement treatment and antibiotic prophylaxis. Heart transplantation led to the resolution of PLE signs and the restitution of IgG levels in 1 transplanted patient. Our experience shows that the immunological follow-up was delayed in all 3 patients. We suggest that all patients should be followed regularly by a clinical immunologist after the Fontan surgery.

Fontan circulation over 30 years. What should we learn from those patients?

Background

This study aimed to evaluate Fontan circulation which was observed over 30 years.

Methods

Forty patients who underwent a Fontan operation between 1974 and 1986 and survived (group S, n = 20) or died in the late period (group LD, n = 20) were evaluated. The median age at operation was 10 years (range 2–32 years). The diagnoses were tricuspid atresia in 21, single ventricle in 9, and others in 10. The Fontan procedure was a right atrium-pulmonary artery graft in 2, atriopulmonary connection in 28, and right atrium-right ventricle anastomosis in 10 (Björk in 4, graft in 6).

Results

Causes of late death were congestive heart failure in 6, sudden death in 4, arrhythmia in 4, and others in 6. Sixteen patients underwent reoperation 23.3 ± 6.5 years after Fontan. Cardiac catheterization was performed at 1 month and 12 years. There were no significant differences in central venous pressure, ventricular ejection fraction, or pulmonary vascular resistance between the two groups. However, changes in ventricular end-diastolic volume suggested volume and pressure overload in group LD. In group S, the latest chest radiographs showed cardiothoracic ratio 51.3% ± 7.6%, oxygen saturation 94% ± 2%, brain natriuretic peptide 153 ± 111 pg ċ mL−1, and Holter monitoring revealed sinus rhythm in 10 patients. New York Heart Association class was I in 12 patients, II in 6, and III in 2.

Conclusions

For long-term Fontan survival, timely total cavopulmonary connection conversion and medication to decrease ventricular volume and pressure load might be important.

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.

Hypoalbuminemia and poor growth predict worse outcomes in pediatric heart transplant recipients

Children with end-stage cardiac failure are at risk of HA and PG. The effects of these factors on post-transplant outcome are not well defined. Using the PHTS database, albumin and growth data from pediatric heart transplant patients from 12/1999 to 12/2009 were analyzed for effect on mortality. Covariables were examined to determine whether HA and PG were risk factors for mortality at listing and transplant. HA patients had higher waitlist mortality (15.81% vs. 10.59%, p = 0.015) with an OR of 1.59 (95% CI 1.09-2.30). Survival was worse for patients with HA at listing and transplant (p ≤ 0.01 and p = 0.026). Infants and patients with congenital heart disease did worse if they were HA at time of transplant (p = 0.020 and p = 0.028). Growth was poor while waiting with PG as risk factor for mortality in multivariate analysis (p = 0.008). HA and PG are risk factors for mortality. Survival was worse in infants and patients with congenital heart disease. PG was a risk factor for mortality in multivariate analysis. These results suggest that an opportunity may exist to improve outcomes for these patients by employing strategies to mitigate these risk factors.

Pulmonary arteriovenous malformations after the superior cavopulmonary shunt: mechanisms and clinical implications

Children with functional single ventricle heart disease are commonly palliated down a staged clinical pathway toward a Fontan completion procedure (total cavopulmonary connection). The Fontan physiology is fraught with long-term complications associated with lower body systemic venous hypertension, eventually resulting in significant morbidity and mortality. The bidirectional Glenn shunt or superior cavopulmonary connection (SCPC) is commonly the transitional stage in single ventricle surgical management and provides excellent palliation. Some studies have demonstrated lower morbidity and mortality with the SCPC when compared with the Fontan. Unfortunately the durability of the SCPC is significantly limited by the development of pulmonary arteriovenous malformations (PAVMs) which have been commonly attributed to the absence of hepatic venous blood flow and the lack of pulsatile flow to the affected lungs. Abnormal angiogenesis has been suggested as a final common pathway to PAVM development. Understanding these fundamental mechanisms through the investigation of angiogenic pathways associated with the pathogenesis of PAVMs would help to develop medical therapies that could prevent or reverse this complication following SCPC. Such therapies could improve the longevity of the SCPC, potentially eliminate or significantly postpone the Fontan completion with its associated complications, and improve long-term survival in children with single ventricle disease.

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.

The relationship of patient medical and laboratory characteristics to changes in functional health status in children and adolescents after the Fontan procedure

Despite hypothesized concerns about deterioration beginning in adolescence, longitudinal data and associated factors regarding standardized assessment of physical functioning are not available for Fontan patients. Parents who participated in the Fontan Cross-Sectional Study completed the Child Health Questionnaire at 2 time points for 245 subjects ages 6-18 years. Associations between change in Physical Functioning Summary Score and baseline patient, medical, and laboratory characteristics (mean age 9.5 ± 1.7 years) and follow-up patient and medical characteristics (mean age 16.2 ± 1.6 years) were determined by regression analyses. During a mean of 6.7 ± 0.4 years, a small (not clinically important) but statistically significant decrease in score from 46.2 ± 11.7 to 44.5 ± 12.1 (p < 0.03) was noted. Subjects with higher baseline scores had a greater decrease in score (r = -0.48; p < 0.001). A multivariable model of patient and medical characteristics (R(2) = 0.11) showed that a greater decrease in score was significantly associated with interim development of asthma (n = 13; parameter estimate [PE] -6.6; p < 0.05) or other chronic respiratory, lung, or breathing problems (n = 13; PE -12.5; p < 0.001) and the presence of protein-losing enteropathy at any time (n = 12; PE -9.4; p = 0.006). Change in score was not significantly associated with baseline laboratory measures of exercise capacity and ventricular characteristics and function. Therefore, although physical functioning may be stable during adolescence for many Fontan patients, deterioration occurs in some in association with respiratory conditions and protein-losing enteropathy. Further longitudinal study is necessary to better understand the relationship between clinical morbidities and functional health status as these patients transition into adulthood.

Long-term Issues After the Fontan Procedure

The Fontan procedure is used to treat various serious congenital heart defects. Although many people who have had the procedure live productively into adulthood, as they age, they face several health issues due to the physiology of the Fontan circulation. This article reviews the 4 types of Fontan procedures and the changes caused by the surgery, including single-ventricle physiology, nonpulsatile pulmonary perfusion, systemic venous hypertension, and intracardiac scarring, as well as their sequelae. Key nursing assessment items and possible treatment strategies are reviewed. Additional topics, including pregnancy in patients who have undergone the procedure, infective endocarditis prophylaxis, and health-related quality of life, are briefly discussed. Options for Fontan failure, including Fontan conversion or transplantation, are presented. Potential future solutions are outlined.

Anesthetic considerations for adults undergoing fontan conversion surgery

There are currently in North America more adults with congenital heart disease than children. This article discusses the anesthetic considerations in adults with single-ventricle physiology and prior repairs who present for Fontan conversion surgery as a demonstration of the challenges of caring for adults undergoing interventions for the repair of congenital heart defects. The care of these patients requires an understanding of the impact of passive pulmonary blood flow and single systemic ventricular physiology. The perioperative morbidity in this patient population remains high.

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.

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.

Oral budesonide as a therapy for protein-losing enteropathy in patients having undergone Fontan palliation

BACKGROUND

  Protein-losing enteropathy is associated with Fontan palliation for single-ventricle physiology and has been difficult to treat. Limited data suggest the successful use of oral budesonide (Entocort, AstraZeneca) as a palliative measure.

METHODS

  We examine our single-institution retrospective experience in eight patients who were treated with this therapy.

RESULTS

  Median pretherapy albumin level was 1.7 g/dL (range 1.0-2.7 g/dL), 3 months after therapy was 3.1 g/dL (range 2-4.8 g/dL), and by the end of the first year was 3.4 g/dL (range 2.1-5.3 g/dL). All patients had at least a transient improvement, and at latest follow-up (median 29 months, range 3-51 months) five patients remain on therapy. Five of eight patients had required pretherapy albumin transfusions; one patient required albumin infusions after therapy. Four patients had side effects associated with the medication.

CONCLUSIONS

  Oral budesonide is an additional therapy that has the potential to improve symptoms and delay need for heart transplantation in this patient population.

A new multiparameter approach to computational simulation for Fontan assessment and redesign

INTRODUCTION

Despite an abundance of prior Fontan simulation articles, there have been relatively few clinical advances that are a direct result of computational methods. We address a few key limitations of previous Fontan simulations as a step towards increasing clinical relevance. Previous simulations have been limited in scope because they have primarily focused on a single energy loss parameter. We present a multi-parameter approach to Fontan modeling that establishes a platform for clinical decision making and comprehensive evaluation of proposed interventions.

METHODS

Time-dependent, 3-D blood flow simulations were performed on six patient-specific Fontan models. Key modeling advances include detailed pulmonary anatomy, catheterization-derived pressures, and MRI-derived flow with respiration. The following performance parameters were used to rank patients at rest and simulated exercise from best to worst performing: energy efficiency, inferior and superior vena cava (IVC, SVC) pressures, wall shear stress, and IVC flow distribution.

RESULTS

Simulated pressures were well matched to catheterization data, but low Fontan pressure did not correlate with high efficiency. Efficiency varied from 74% to 96% at rest, and from 63% to 91% with exercise. Distribution of IVC flow ranged from 88%/12% (LPA/RPA) to 53%/47%. A "transcatheter" virtual intervention demonstrates the utility of computation in evaluating interventional strategies, and is shown to result in increased energy efficiency.

CONCLUSIONS

A multiparameter approach demonstrates that each parameter results in a different ranking of Fontan performance. Ranking patients using energy efficiency does not correlate with the ranking using other parameters of presumed clinical importance. As such, current simulation methods that evaluate energy dissipation alone are not sufficient for a comprehensive evaluation of new Fontan designs.

Liver disease after the Fontan procedure: what the hepatologist needs to know

Fifty years ago, only a quarter of infants born with congenital heart disease (CHD) survived beyond the first year of life. It has been estimated that 80% to 85% of patients can expect to reach adulthood. Today, there are close to 1 million adults living with CHD in the United States alone. Since its introduction, the Fontan operation has become established as the dominant surgical repair in patients with univentricular heart physiology. Long-term morbidity associated with this procedure is being more commonly appreciated and liver complications have become more frequently apparent. Hepatologist awareness and familiarity in managing this population alongside the CHD specialist is important for the care of these patients. This dual perspective can provide comprehensive integrated care.

Four decades of Fontan palliation

The Fontan palliation was introduced in 1968 to treat cardiac malformations unsuitable for biventricular repair. This procedure has transformed the surgical management of congenital heart disease. In this Review, we reflect on the outcomes and clinical problems associated with this unique circulation after more than 40 years of experience. We also summarize the evolution of the Fontan procedure, highlight the long-term clinical issues and their management, and consider future expectations of a circulation driven by a single ventricle with the systemic and pulmonary blood flow in series rather than in parallel.

Angiopoietin-2 in experimental colitis

BACKGROUND

The pathophysiology of inflammatory bowel disease (IBD) includes leukocyte infiltration, blood and lymphatic remodeling, weight loss and protein enteropathy. The roles of angiopoietin-2 (Ang-2) in initiating gut inflammation, leukocyte infiltration and angiogenesis are not well understood.

METHODS

Disease activity index, histopathological scoring, myeloperoxidase assay, immunohistochemistry and sodium dodecyl sulphate- polyacrylamide gel electrophoretic methods were employed in the present study to address the roles of Ang-2 in experimental colitis.

RESULTS

Several important differences were seen in the development of experimental IBD in Ang-2(-/-) mice. Although weight change and disease activity differ only slightly in WT and Ang-2(-/-) + DSS treated mice, leukocyte infiltration, inflammation and blood and lymphatic vessel density is significantly attenuated compared to WT + DSS mice. Gut capillary fragility and water export (stool blood and form) appear significantly earlier in Ang-2(-/-) + DSS mice vs. WT. Colon lengths were also significantly reduced in Ang-2(-/-) and gut histopathology was less severe in Ang-2(-/-) compared to WT + DSS. Lastly, the decrease in serum protein content in WT + DSS was less severe in Ang-2(-/-) + DSS, thus protein losing enteropathy (PLE) a feature of IBD is relieved by Ang-2(-/-).

CONCLUSION

These data demonstrate that in DSS colitis, Ang-2 mediates inflammatory hemangiogenesis, lymphangiogenesis and neutrophil infiltration to reduce some, but not all clinical features of IBD. The implications for Ang-2 manipulation in the development of IBD and other inflammatory diseases and treatments involving Ang-2 are discussed.

Protein-losing enteropathy: case illustrations and clinical review

Protein-losing enteropathy (PLE) is a rare syndrome of gastrointestinal protein loss that may complicate a variety of diseases. The primary causes can be divided into erosive gastrointestinal disorders, nonerosive gastrointestinal disorders, and disorders involving increased central venous pressure or mesenteric lymphatic obstruction. The diagnosis of PLE should be considered in patients with hypoproteinemia after other causes, such as malnutrition, proteinuria, and impaired protein synthesis due to cirrhosis, have been excluded. The diagnosis of PLE is most commonly based on the determination of fecal alpha-1 antitrypsin clearance. Treatment of PLE targets the underlying disease but also includes dietary modification, supportive care, and maintenance of nutritional status. In this article, cases illustrating a variety of clinical presentations and etiologies of PLE are presented, and its diagnostic approach and treatment are reviewed.

Evaluating failing Fontans for heart transplantation: predictors of death

BACKGROUND

Late complications of the Fontan operation represent a significant management challenge. Failing Fontan patients have two modes of presentation: impaired ventricular function (IVF) and those with preserved ventricular function (PVF) but with failing Fontan physiology (protein-losing enteropathy [PLE] and plastic bronchitis [PB]). This study evaluated whether failing Fontan patients referred for heart transplantation had a different outcome based on the mode of presentation.

METHODS

The medical records of all Fontan patients evaluated for heart transplantation at a single institution from 1994 to 2008 were retrospectively reviewed. Demographic, hemodynamic, and laboratory data were collected. Patients were stratified into an IVF or PVF group by echocardiographic criteria. Descriptive statistics and Kaplan-Meier analysis were used for hypothesis testing.

RESULTS

Thirty-four Fontan patients were evaluated for heart transplantation. According to echo description of systolic function, 18 were categorized as IVF and 16 as PVF. The IVF group had a significantly lower cardiac index and venous oxygen saturation, and significantly higher systemic vascular resistance vs the PVF group (p < 0.05). PLE or PB was present in 13 PVF patients and none in the IVF group. Twenty patients underwent transplantation, with similar rates amongst the IVF and PVF groups. Within 1 year from evaluation, 2 IVG patients and 7 PVF patients had died (p = 0.052).

CONCLUSIONS

Failing Fontan patients with PVF have decreased overall survival independent of whether they underwent transplantation. This trend indicates a need to improve the management and timing for transplantation amongst this population.