Protein-losing enteropathy after the Fontan operation: an international multicenter study. PLE study group

Protein-losing enteropathy after fontan surgery: insights from Vietnamese clinical experience and the need for global collaboration

Protein-losing enteropathy remains a formidable and underrecognised complication following Fontan surgery, contributing significantly to morbidity and mortality among affected patients. Despite substantial progress in managing single-ventricle CHDs, protein-losing enteropathy persists as a major clinical challenge, particularly in resource-constrained environments where specialised diagnostic modalities are scarce. This manuscript discusses the prevalence, clinical presentation, diagnostic hurdles, and management of protein-losing enteropathy in post-Fontan patients, drawing from clinical experiences in Vietnam. Among 95 post-Fontan patients reviewed, the prevalence of protein-losing enteropathy was 4.2%, with considerable morbidity necessitating invasive interventions and, in some cases, resulting in mortality. Diagnostic limitations, including restricted access to alpha-1-antitrypsin clearance testing, highlight the urgent need for heightened clinical suspicion and pragmatic diagnostic approaches. We advocate for integrating low-cost, widely accessible screening measures, such as routine serum protein monitoring, into standard post-Fontan care protocols to enhance early detection and management of protein-losing enteropathy. Furthermore, we underscore the critical importance of global collaboration and multicentre research initiatives to address the worldwide burden of protein-losing enteropathy, facilitate resource-sharing, and develop evidence-based interventions. Coordinated international efforts are essential to closing diagnostic and treatment gaps, ultimately improving survival and quality of life for patients living with the Fontan circulation.

Phase 2 Open-label, Single-arm, Multi-center Clinical Trial to Evaluate the Efficacy and Safety of Camostat Mesylate in Patients with Protein-losing Enteropathy After Fontan Operation

Protein-losing enteropathy (PLE) is a serious complication after the Fontan operation with limited treatment options. This phase 2, multi-center, open-label trial evaluated the efficacy and safety of Camostat Mesylate (CM), a serine protease inhibitor, as adjunctive therapy for PLE. Nineteen patients aged 4 years and older with PLE after the Fontan operation were enrolled. CM was administered for six months in addition to their individualized conventional treatments. Assessments were made at 1, 3, and 6 months of CM administration, and at one month after CM discontinuation. Outcomes evaluated were the changes in serum albumin level, stool alpha-1 antitrypsin, and clinical symptoms such as, diarrhea, edema, weight change, and ascites. Of the 19 patients enrolled, 4 voluntarily withdrew consent, and the data from the 15 patients who completed the study were analyzed. Their median age was 15.0 years (interquartile range, 12.0-21.5) and the median time between the Fontan surgery and PLE diagnosis was 2.4 years. Serum albumin levels increased from 2.2 to 2.5 g/dL (p = 0.183), while stool alpha-1 antitrypsin levels significantly decreased from 215.6 to 75.5 mg/dL (p = 0.016) over six months. Patients with baseline diarrhea showed notable improvements: serum albumin increased from 1.8 to 2.4 g/dL (p = 0.138) and stool alpha-1 antitrypsin decreased from 220.3 to 75.5 mg/dL (p = 0.075) over 6 months. No serious adverse events occurred. CM demonstrated significant reductions in gastrointestinal protein losses, particularly in patients with baseline diarrhea. Trial registration NCT05474664.

Fontan-Associated Liver Disease

Fontan-associated liver disease (FALD) occurs in all patients who have undergone Fontan palliation for functional single ventricle congenital heart defects. While liver fibrosis is universal in patients who have undergone Fontan palliation, FALD may lead to more serious consequences including portal hypertension, cirrhosis, and hepatocellular carcinoma. Scientific studies of the pathophysiology and clinical management of FALD have been limited to date by the heterogeneous nature of the disease, relatively small population of patients with Fontan physiology, and inaccuracy of noninvasive staging tests. As survival after the Fontan procedure improves, the population of adults with Fontan physiology is growing, leading to more severe extracardiac complications related to the Fontan circulation and growing demand for heart and liver transplantation. The accurate evaluation, staging, and management of FALD comprises a clinical challenge which requires expert multidisciplinary input.

Biventricular Repair of Univentricular Heart Lowers Risk of Liver Disease Compared With the Fontan Operation

Background

The Fontan operation is associated with chronic venous hypertension, liver and renal disease, and several other sequelae. The alterative surgical approach, when feasible, a biventricular conversion (BiV), may diminish some of these long-term risks.

Objectives

The aim of this study was to compare long-term outcomes of patients undergoing BiV with those undergoing a destination Fontan operation.

Methods

We identified all patients with univentricular physiology cared for at Boston Children's Hospital between 2007 and 2022 and divided them into those who received BiV or Fontan operations. Outcomes included 10-year incidences of modified major adverse cardiovascular events (MACE), liver dysfunction, renal dysfunction, and transplant-free survival. Outcomes in the 2 groups were compared using propensity matching.

Results

A total of 927 patients were evaluated, 341 BiV and 586 Fontan. Following propensity matching, 258 patients from each group were compared. There were no differences between groups in estimated 10-year freedom from MACE (P = 0.70), transplant-free survival (P = 0.70), or freedom from renal disease (P = 0.60). However, estimated 10-year freedom from liver disease was greater in BiV patients (82% BiV vs 71% Fontan, P = 0.02). Incidence rate per 100 person-years follow-up of surgical interventions and readmissions was higher among BiV patients (10.11 vs 1.85, P < 0.001 and 13.09 vs 9.6, P = 0.002), while catheter-based interventions were higher among Fontan patients (8.41 vs 4.63, P < 0.001).

Conclusions

Among a contemporary cohort of patients with single ventricle anatomy, BiV provide comparable long-term survival and lower risk of liver disease when compared to patients who have undergoing Fontan operations.

Fontan-associated liver disease: the importance of multidisciplinary teamwork in its management

The Fontan operation, which directly connects the superior and inferior vena cava to the pulmonary artery, is a palliative surgery for children with a functional or anatomic single ventricle. This procedure leads to hemodynamic changes (Fontan circulation) in patients, who tend to develop congestive hepatic fibrosis characterized by sinusoidal fibrosis and dilatation beginning approximately 10 years after the procedure. In addition, in the context of severe fibrosis and cirrhosis, hepato-gastrointestinal complications including hepatocellular carcinoma, focal nodular hyperplasia, and portal hypertension can arise. Fontan-associated liver disease (FALD) encompasses the broad spectrum of liver alterations secondary to postoperative hemodynamic changes, and the effective management of FALD requires contributions from specialists in hepatology, gastroenterology, surgery, radiology, histopathology, and pediatric and adult cardiology. In this article, we outline the pathogenesis of FALD and discuss the importance of a multidisciplinary collaborative approach to its management.

Thoracic Lymphatic Perfusion Patterns Assessed by Magnetic Resonance Imaging and Late Fontan Failure

BACKGROUND

Fontan circulation maintains an elevated venous pressure; this promotes venous and lymphatic congestion and may lead to late circuit failure. Our objective was to determine the association between thoracic lymphatic perfusion patterns assessed by magnetic resonance imaging and late Fontan failure.

METHODOLOGY

A retrospective study was performed. We included patients who underwent the Fontan procedure between January 2005 and December 2019 and who were evaluated with lymphatic mapping using magnetic resonance imaging. Lymphatic abnormalities were classified into four types. The prevalence of late failure was determined, and logistic regression analysis was performed to establish the association between the variables of interest and the outcome.

RESULTS

Fifty-four patients were included with a mean age at surgery of 8.8 years ± 3.5 years; 42.6% (n = 23) were men. The most frequent diagnosis was tricuspid atresia (50%, n = 27), and the Fontan procedures were mainly performed using an extracardiac conduit (96.3%, n = 52). The prevalence of late Fontan failure was 35.2%. The lymphatic perfusion patterns observed were Type 1 in 25.9% (n = 14), Type 2 in 46.3% (n = 25), Type 3 in 25.9% (n = 14), and Type 4 in 1.8% (n = 1), with no differences in relation to late failure. (p = 0.42). The age at surgery was found to be a factor associated with the late Fontan failure (OR: 1.23; 95% CI: 1.02-1.48; p = 0.02).

CONCLUSIONS

One-third of patients with Fontan circulation may experience late failure, not significantly associated with lymphatic changes, but when the total cavopulmonary connection is completed at an older age.

The Long-term Outcomes and Risk Factors of Complications After Fontan Surgery: From the Korean Fontan Registry (KFR)

BACKGROUND AND OBJECTIVES

This study aimed to analyze the outcomes of Fontan surgery in the Republic of Korea, as there were only a few studies from Asian countries.

METHODS

The medical records of 1,732 patients who underwent Fontan surgery in 10 cardiac centers were reviewed.

RESULTS

Among them, 1,040 (58.8%) were men. The mean age at Fontan surgery was 4.3±4.2 years, and 395 (22.8%) patients presented with heterotaxy syndrome. According to the types of Fontan surgery, 157 patients underwent atriopulmonary (AP) type; 303, lateral tunnel (LT) type; and 1,266, extracardiac conduit (ECC) type. The overall survival rates were 91.7%, 87.1%, and 74.4% at 10, 20, and 30 years, respectively. The risk factors of early mortality were male, heterotaxy syndrome, AP-type Fontan surgery, high mean pulmonary artery pressure (mPAP) in pre-Fontan cardiac catheterization, and early Fontan surgery year. The risk factors of late mortality were heterotaxy syndrome, genetic disorder, significant atrioventricular valve regurgitation (AVVR) before Fontan surgery, high mPAP in pre-Fontan cardiac catheterization, and no fenestration.

CONCLUSIONS

In Asian population with a high incidence of heterotaxy syndrome, the heterotaxy syndrome was identified as the poor prognostic factors for Fontan surgery. The preoperative low mPAP and less AVVR are associated with better early and long-term outcomes of Fontan surgery.

Combined Percutaneous Transhepatic Lymphatic Embolization and Peroral Duodenal Mucosal Radiofrequency Ablation to Manage Protein-Losing Enteropathy

Percutaneous transhepatic lymphatic embolization (PTLE) and peroral esophagogastroduodenoscopy (EGD) duodenal mucosal radiofrequency (RF) ablation were performed to manage protein-losing enteropathy (PLE) in patients with congenital heart disease. Five procedures were performed in 4 patients (3 men and 1 woman; median age, 49 years; range, 31-71 years). Transhepatic lymphangiography demonstrated abnormal periduodenal lymphatic channels. After methylene blue injection through transhepatic access, subsequent EGD evaluation showed methylene blue extravasation at various sites in the duodenal mucosa. Endoscopic RF ablation of the leakage sites followed by PTLE using 3:1 ethiodized oil-to-n-butyl cyanoacrylate glue ratio resulted in improved symptoms and serum albumin levels (before procedure, 2.6 g/dL [SD ± 0.2]; after procedure, 3.5 g/dL [SD ± 0.4]; P = .004) over a median follow-up of 16 months (range, 5-20 months). Transhepatic lymphangiography and methylene blue injection with EGD evaluation of the duodenal mucosa can help diagnose PLE. Combined PTLE and EGD-RF ablation is an option to treat patients with PLE.

Thrombocytopenia is Associated with Higher Fontan Pressure and Increased Morbidity in Patients with Fontan Circulation

After the Fontan procedure, patients require lifelong follow-up due to significant late morbidity and mortality. Thrombocytopenia is seen frequently post-Fontan, likely due to secondary hypersplenism from elevated Fontan pressure. We investigated platelet counts in patients with a Fontan circulation and assessed associations with catheterization data and clinical outcomes. This retrospective study included 92 patients (33% female) post-Fontan who had a complete blood count performed between January 2011 and July 2023. The age at evaluation was 24.0 ± 8.9 years. Outcomes measured included elevated Fontan pressure (≥ 15 mmHg), Fontan-associated liver disease (FALD), unscheduled admissions, transplant, and death. Participants with thrombocytopenia (≤ 150,000/µL) had significantly higher rates of elevated Fontan pressure (OR 8.1, 95% CI 1.3-52.7, p = 0.03), FALD (OR 4.1, 95% CI 1.6-10.6, p = 0.004), and unscheduled admissions (362 ± 577 versus 115 ± 185 admissions per 1000 patient-years, p = 0.02). Thrombocytopenia post-Fontan is associated with elevated Fontan pressure, FALD, and increased morbidity. Platelet count could serve as a non-invasive factor in identifying patients at risk of decompensation.

Lymphatic interventions in congenital heart disease

Congenital heart disease affects 1/100 live births and is one of the most common congenital abnormalities. The relationship between congenital heart disease and lymphatic abnormalities and/or dysfunction is well documented and can be grossly divided into syndromic and non-syndromic etiologies. In patients with genetic syndromes (as examples listed above), there are known primary abnormal lymphatic development leading to a large pleiotropic manifestation of lymphatic dysfunction. Non-syndromic patients, or those without clear genetic etiologies for their lymphatic dysfunction, are often thought to be secondary to physiologic abnormalities as sequelae of congenital heart disease and palliative surgeries. Patients with congenital heart disease and lymphatic dysfunction have a wide variety of clinical manifestations for which there were not many therapeutic interventions available. The development of new imaging techniques allows us to understand better the pathophysiology of these problems and to develop different percutaneous interventions aiming to restore normal lymphatic function.

Lymphatic failure and lymphatic interventions: Knowledge gaps and future directions for a new frontier in congenital heart disease

Lymphatic failure is a broad term that describes the lymphatic circulation's inability to adequately transport fluid and solutes out of the interstitium and into the systemic venous circulation, which can result in dysfunction and dysregulation of immune responses, dietary fat absorption, and fluid balance maintenance. Several investigations have recently elucidated the nexus between lymphatic failure and congenital heart disease, and the associated morbidity and mortality is now well-recognized. However, the precise pathophysiology and pathogenesis of lymphatic failure remains poorly understood and relatively understudied, and there are no targeted therapeutics or interventions to reliably prevent its development and progression. Thus, there is growing enthusiasm towards the development and application of novel percutaneous and surgical lymphatic interventions. Moreover, there is consensus that further investigations are needed to delineate the underlying mechanisms of lymphatic failure, which could help identify novel therapeutic targets and develop innovative procedures to improve the overall quality of life and survival of these patients. With these considerations, this review aims to provide an overview of the lymphatic circulation and its vasculature as it relates to current understandings into the pathophysiology and pathogenesis of lymphatic failure in patients with congenital heart disease, while also summarizing strategies for evaluating and managing lymphatic complications, as well as specific areas of interest for future translational and clinical research efforts.

Contemporary Management of the Failing Fontan

Adult patients with congenital heart disease have now surpassed the pediatric population due to advances in surgery and improved survival. One such complex congenital heart disease seen in adult patients is the Fontan circulation. These patients have complex physiology and are at risk for several complications, including thrombosis of the Fontan pathway, pulmonary vascular disease, heart failure, atrial arrhythmias, atrioventricular valve regurgitation, and protein-losing enteropathy. This review discusses the commonly encountered phenotypes of Fontan circulatory failure and their contemporary management.

Are dynamic measurements of central venous pressure in Fontan circulation during exercise or volume loading superior to resting measurements?

BACKGROUND

The main objective measure to assess the health of the Fontan circulation is the pressure measurement of the superior vena cava or pulmonary arteries. We reviewed the literature for benefits of measuring resting pressure in the Fontan circuit and explored whether dynamic measurement by volume loading or exercise has the potential to refine this diagnostic tool.

METHODS

PubMed was searched for articles showing a relationship between resting post-operative central venous pressure or pulmonary artery pressure and Fontan failure. Relationships between post-operative central venous pressure or pulmonary artery pressure and volume loading changes, such as during exercise or volume loading during cardiac catheterization, were also queried.

RESULTS

A total of 44 articles mentioned relationships between resting central venous pressure or pulmonary artery pressure and Fontan failure. Only 26 included an analysis between the variables and only seven of those articles found pressure to be predictive of Fontan failure. Ten articles examined the relationship between exercise or volume loading and outcomes and demonstrated a large individual variation of pressures under these dynamic conditions.

CONCLUSIONS

Based on current literature, there is not a lot of strong evidence to show that elevated resting central venous pressure or pulmonary artery pressure is predictive of Fontan failure. Some individuals experience dramatic increases in central venous pressure or pulmonary artery pressure under increased loading conditions with exercise or bolus fluid infusion, while others experience increases closer to that of a healthy control population. Further studies are needed to examine whether more dynamic and continuous monitoring of systemic venous pressures might better predict outcomes in patients with Fontan circulation.

Fontan surgery failure: risk factors and experience in a Colombian reference centre

BACKGROUND

The Fontan procedure is considered one of the most remarkable achievements in paediatric cardiology and cardiac surgery. Its final anatomical objective is a venous return through the superior and inferior vena cava. The complications inherent to this procedure and subsequent failure are its limitations.

OBJECTIVE

To describe the clinical and haemodynamic characteristics of patients with Fontan failure and define the risk factors associated with it, with its short- and long-term outcomes during a 21-year observation period.

METHODS

This is a retrospective follow-up study in which 15 patients diagnosed with Fontan failure in the single-ventricle programme of a high-complexity hospital in Medellín, Colombia, between 2001 and 2022 were included.

RESULTS

One hundred and eight patients were identified in whom the Fontan procedure was performed, and 17 met the failure criteria. 82.4% were men, with a median age of 4.3 years. Ebstein's anomaly was the most common diagnosis, 29.4%. All patients underwent Fontan with an extracardiac tube following the procedure. According to the type of failure, 58.8% of patients presented protein-losing enteropathy and 17.6% plastic bronchitis. During follow-up, 5.9% of patients died.

CONCLUSION

Fontan surgery in our centre is an option for patients with univentricular physiology. The correct selection of the patient is essential to mitigate failure risks.

Dysbiosis of gut microbiota in patients with protein-losing enteropathy after the Fontan procedure

BACKGROUND

There is a lack of predictive biomarkers for the onset or activity of protein-losing enteropathy (PLE), a Fontan procedure-associated complication. Here, we aimed to identify the gut microbiota composition of patients with active PLE and investigate its relationship with PLE activity.

METHODS

This multicenter case-control study involved patients who developed PLE (n = 16) after the Fontan procedure and those who did not (non-PLE; n = 20). Patients with PLE who maintained a serum albumin level of ≥3 g/dL for >1 year were included in the remissive-stage-PLE group (n = 9) and those who did not maintain this level were included in the active-PLE group (n = 7). 16S rRNA gene sequencing analysis of fecal samples was performed using QIIME2 pipeline. Alpha (Shannon and Faith's phylogenetic diversity indices) and beta diversity was assessed using principal coordinate analysis based on unweighted UniFrac distances.

RESULTS

Shannon and Faith's phylogenetic diversity indices were lower in the active-PLE group than in the remissive-stage- (q = 0.028 and 0.025, respectively) and non-PLE (q = 0.028 and 0.017, respectively) groups. Analysis of beta diversity revealed a difference in the microbiota composition between the active-PLE and the other two groups. Linear discriminant effect size analysis demonstrated differences in the relative abundance of Bifidobacterium and Granulicatella spp., and Ruminococcus torques between patients with active- and those with remissive-stage-PLE.

CONCLUSIONS

Gut microbiota dysbiosis was observed in patients with active PLE. Changes in the bacterial composition of the gut microbiota and decreased diversity may be associated with the severity of PLE.

Complex Congenital Heart Disease in the Adult

Congenital heart disease (CHD), a heterogeneous group of structural abnormalities of the cardiovascular system, is the most frequent cause of severe birth defects. Related to improved pediatric outcomes, there are now more adults living with CHD, including complex lesions, than children. Adults with CHD are at high risk for complications related to their underlying anatomy and past surgical palliative interventions. Adults with CHD require close monitoring and proactive management strategies to improve outcomes.

Anorexia nervosa in a postoperative patient with Ebstein's anomaly

Background

Along with the improved prognosis of patients with congenital heart disease, the associated diverse complications are under scrutiny. Due to various medical restrictions on their upbringing, patients with congenital heart disease often have coexisting mental disorders. However, reports on patients with congenital heart disease and coexisting eating disorders are rare. Here, we report the case of a patient who developed anorexia nervosa (AN) following surgery for Ebstein's anomaly.

Case Presentation

A 21-year-old female with Ebstein's anomaly who underwent Fontan surgery was transferred to our institution with suspected AN after >2 years of intermittent stays at a medical hospital for decreased appetite. Initially, she did not desire to lose weight or fear obesity, and we suspected that she was suffering from appetite loss due to a physical condition associated with Fontan circulation. However, the eating disorder pathology gradually became more apparent.

Conclusion

Our experience suggests that patients with congenital heart disease are more likely to have a psychological background and physical problems that might contribute to eating disorders than the general population.

Protein-Losing Enteropathy and Plastic Bronchitis Following the Total Cavopulmonary Connections

BACKGROUND

We aimed to evaluate incidence, outcomes, and predictors of protein-losing enteropathy (PLE) and plastic bronchitis (PB) in a cohort of total cavopulmonary connection (TCPC).

METHODS

We included 620 consecutive patients undergoing TCPC between 1994 and 2021. Prevalence and predictors for onset of PLE/PB were evaluated. Death and heart transplantation after onset of PLE/PB were examined.

RESULTS

A total of 41 patients presented with PLE/PB (31 with PLE, 15 with PB, and 5 developed both PLE and PB). Their median age at TCPC was 2.2 (interquartile ranges [IQRs], 1.7-3.7) years, and time period to onset for PLE was 2.6 (IQR: 1.0-6.6) years and for PB was 1.1 (IQR: 0.3-4.1) years after TCPC. Independent factors for developing PLE/PB were dominant right ventricle (RV, hazard ratio [HR], 2.243; 95% confidence interval [CI], 1.129-4.458, P = .021) and prolonged pleural effusion after TCPC (HR, 2.101; 95% CI, 1.090-4.049, P = .027). In PLE/PB population, freedom from death or transplantation after PLE/PB diagnosis at 5 and 10 years were 88.7% and 76.4%, respectively. Eleven surgical interventions were performed in 10 patients, comprising atrioventricular valve repairs (n = 4), Fontan pathway revisions (n = 2), pacemaker implantation (n = 2), secondary fenestration (n = 1), diaphragm plication (n = 1), and ventricular assist device implantation (n = 1). In nine patients, a recovery from PLE with the resolution of PLE symptoms and normal protein levels was achieved. Eight patients died and the remaining continued to have challenging protein loss.

CONCLUSIONS

Protein-losing enteropathy and PB remain severe complications in the cohort of TCPC. Patients with dominant RV, and prolonged pleural effusions, were at risk for PLE/PB.

The Fontan immunophenotype and post-transplant outcomes in children: A multi-institutional study

BACKGROUND

Patients after Fontan palliation represent a growing pediatric population requiring heart transplant (HTx) and often have lymphopenia (L) and/or hypogammaglobinemia that may be exacerbated by protein-losing enteropathy (PLE, P). The post-HTx effects of this altered immune phenotype are not well studied.

METHODS

In this study of the Pediatric Heart Transplant Society Registry, 106 Fontan patients who underwent HTx between 2005 and 2018 were analyzed. The impact of lymphopenia and PLE on graft survival, infection, rejection, and malignancy was analyzed at 1 and 5 years post-HTx.

RESULTS

The following combinations of lymphopenia and PLE were noted: +L+P, n = 37; +L-P, n = 23; -L+P, n = 10; and -L-P, n = 36. Graft survival between the groups was similar within the first year after transplant (+L+P: 86%, +L-P: 86%, -L+P: 87%, -L-P: 89%, p = .9). Freedom from first infection post-HTx was greatest among -L-P patients compared to patients with either PLE, lymphopenia, or both; with a 22.1% infection incidence in the -L-P group and 41.4% in all others. These patients had a significantly lower infection rate in the first year after HTx (+L+P: 1.03, +L-P: 1, -L+P: 1.3, -L-P: 0.3 infections/year, p < .001) and were similar to a non-single ventricle CHD control group (0.4 infections/year). Neither freedom from rejection nor freedom from malignancy 1 and 5 years post-HTx, differed among the groups.

CONCLUSIONS

Fontan patients with altered immunophenotype, with lymphopenia and/or PLE, are at increased risk of infection post-HTx, although have similar early survival and freedom from rejection and malignancy. These data may encourage alternative immunosuppression strategies and enhanced monitoring for this growing subset of patients.

Surrogates of Muscle Mass on Cardiac MRI Correlate with Exercise Capacity in Patients with Fontan Circulation

BACKGROUND

Sarcopenia is an increasingly recognized marker of frailty in cardiac patients. Patients with a history of congenital heart disease and Fontan procedure have a higher risk of developing progressive muscle wasting. Our objective was to determine if we could use routine cardiac MRI (CMR) for the surveillance of muscle wasting.

METHODS

A retrospective study of all Fontan patients (n = 75) was conducted at our institution, with CMR performed from 2010 to 2022 and exercise stress testing performed within 12 months (4.3 ± 4.2 months). The skeletal muscle area (SMA) for the posterior paraspinal and anterior thoracic muscles were traced and indexed for body surface area (BSA). Patients were stratified by percentile into the upper and lower quartiles, and the two groups were compared. Multivariable regression was performed to control for sex and age.

RESULTS

There was a significant positive association of both anterior (r = 0.34, p = 0.039) and paraspinal (r = 0.43, p = 0.007) SMA to peak VO2. Similarly, paraspinal but not anterior SMA was negatively associated with the VE/VCO2 (r = -0.45, p = 0.006). The upper quartile group had significantly more males (18/19 vs. 8/20; p = 0.0003) and demonstrated a significantly higher peak VO2 (32.2 ± 8.5 vs. 23.8 ± 4.7, p = 0.009), a higher peak RER (1.2 ± 0.1 vs. 1.1 ± 0.04, p = 0.007), and a significantly lower VE/VCO2 (32.9 ± 3.6 vs. 40.2 ± 6.2, p = 0.006) compared to the lowest quartile. The association of SMA to VO2 peak and VE/VCO2 was redemonstrated after controlling for sex and age.

CONCLUSION

Thoracic skeletal muscle area may be an effective surrogate of muscle mass and is correlated to several measures of cardiorespiratory fitness post-Fontan. CMR would be an effective tool for the surveillance of sarcopenia in post-Fontan patients given its accessibility and routine use in these patients.

Lymphatic Intervention, the Frontline of Modern Lymphatic Medicine: Part II. Classification and Treatment of the Lymphatic Disorders

Lymphatic disorders encompass a broad spectrum of diseases involving the lymphatic system, ranging from traumatic lymphatic leaks to lymphatic malformations. Lymphatic disorders can be categorized into traumatic and non-traumatic disorders according to their etiology. These two categories may be further divided into subgroups depending on the anatomical location of the lymphatic pathology and their association with clinical syndromes. Thoracic duct embolization was a milestone in the field of lymphatic intervention that encouraged the application of percutaneous embolization techniques to treat leaks and reflux disorders in the lymphatic system. Additional access routes for embolization, including retrograde thoracic duct and transhepatic lymphatic access, have also been developed. This article comprehensively reviews a variety of options for the treatment of lymphatic disorders, from conservative management to the most recent embolization techniques.

Quantification of lymphatic burden in patients with Fontan circulation by T2 MR lymphangiography and associations with adverse Fontan status

AIMS

To quantify thoracic lymphatic burden in paediatric Fontan patients using MRI and correlate with clinical status.

METHODS AND RESULTS

Paediatric Fontan patients (<18-years-old) with clinical cardiac MRI that had routine lymphatic 3D T2 fast spin echo (FSE) imaging performed from May 2017 to October 2019 were included. 'Lymphatic burden' was quantified by thresholding-based segmentation of the 3D T2 FSE maximum intensity projection image and indexed to body surface area, performed by two independent readers blinded to patient status. There were 48 patients (27 males) with median age at MRI of 12.9 (9.4-14.7) years, time from Fontan surgery to MRI of 9.1 (5.9-10.4) years, and follow-up time post-Fontan surgery of 9.4 (6.6-11.0) years. Intraclass correlation coefficient between two observers for lymphatic burden was 0.96 (0.94-0.98). Greater lymphatic burden correlated with post-Fontan operation hospital length of stay and duration of chest tube drainage (rs = 0.416, P = 0.004 and rs = 0.439, P = 0.002). Median lymphatic burden was greater in patients with chylous effusions immediately post-Fontan (178 (118-393) vs. 113 (46-190) mL/m2, P = 0.028), and in patients with composite adverse Fontan status (n = 13) defined by heart failure (n = 3), transplant assessment (n = 2), recurrent effusions (n = 6), Fontan thrombus (n = 2), and/or PLE (n = 6) post-Fontan (435 (137-822) vs. 114 (51-178) mL/m2, P = 0.003). Lymphatic burden > 600 mL/m2 was associated with late adverse Fontan status with sensitivity of 57% and specificity of 95%.

CONCLUSION

Quantification of MR lymphatic burden is a reliable tool to assess the lymphatics post-Fontan and is associated with clinical status.

27 years of experience with the Fontan procedure: characteristics and clinical outcomes of children in a tertiary referral hospital

BACKGROUND

The Fontan operation has improved the survival of children born with congenital heart disease with single ventricle physiology. The most widely adopted variations of the Fontan procedure are the extracardiac conduit, the lateral tunnel ve the intra/extracardiac conduit with fenestration. Despite advances in the treatment and prevention of early and late complications that may develop after Fontan surgery, morbidity still remains an important problem.

METHODS

304 patients who underwent Fontan surgery in our center between 1995 and 2022 were included in our study. The complications that developed in patients who underwent primary Fontan or lateral tunnel surgery and extracardiac conduit Fontan application were compared.

RESULTS

Classic Fontan surgery and lateral tunnel surgery were performed in 26 of the patients, and extracardiac Fontan surgery was performed in 278 patients. 218 of 304 cases were patients with single ventricular pathology. 86 cases were patients with two ventricular morphologies but complex cardiac pathology. Fenestration was performed in only 6 patients, other patients did not require fenestration. The mean follow-up period of our patients was 12 years (3 months-27 years). When the complications between Fontan procedures were compared in our study, it was found that the length of hospital stay and mortality were statistically significantly reduced in patients who underwent extracardiac Fontan surgery. There was no significant difference in terms of complications that can be seen after Fontan surgery and the length of stay in the intensive care unit.

CONCLUSION

Fontan complex is a palliative surgery for children with complex heart disease. Palliative surgical operations aimed at the preparation of the Fontan circulation lead to the preparation of the pulmonary vascular bed and the preservation of ventricular function. The techniques applied in Fontan surgery affect the early and long-term complications and the survival of the patients. In our study, when we examined the patients who extracardiac conduit Fontan procedure for the non-cardiac route, we found that mortality and morbidity were minimal.

Fontan failure: phenotypes, evaluation, management, and future directions

OBJECTIVES

Management of "failing" and "failed" Fontan circulation, particularly the indications, timing, and type of re-intervention, currently remains nebulous. Factors contributing to pathogenesis and mortality following Fontan procedure differ between children and adults.

METHODS

Since organ systems in individual patients are affected differently, we searched the extant literature for a "failing" and "failed" Fontan reviewing the clinical phenotypes, diagnostic modalities, pharmacological, non-pharmacological, and surgical techniques employed, and their outcomes.

RESULTS

A total of 410 investigations were synthesised. Although proper candidate selection, thoughtful technical modifications, timely deployment of mechanical support devices, tissue-engineered conduits, and Fontan takedown have decreased the peri-operative mortality from 9 to 15% and 1 to 3% per cent in recent series, pernicious changes in organ function are causing long-term patient attrition. In the setting of a failed Fontan circulation, literature documents three surgical options: Fontan revision, Fontan conversion, or cardiac transplantation. The reported morbidity of 25% and mortality of 8-10% among Fontan conversion continue to improve in select institutions. While operative mortality following cardiac transplantation for Fontan failure is 30% higher than for other CHDs, there is no difference in long-term survival with actuarial 10-year survival of around 54%. Mechanical circulatory assistance, stem cells, and tissue-engineered Fontan conduit for destination therapy or as a bridge to transplantation are in infancy for failing Fontan circulation.

CONCLUSIONS

An individualised management strategy according to clinical phenotypes may delay the organ damage in patients with a failing Fontan circulation. At present, cardiac transplantation remains the last stage of palliation with gradually improving outcomes.

Early Experience With Reverse Double Switch Operation for the Borderline Left Heart

This study reviews our early experience with the "reverse" double switch operation (R-DSO) for borderline left hearts. A retrospective review of children with borderline left hearts who underwent R-DSO between 2017 and 2021 was conducted. Patient characteristics and early hemodynamic and clinical outcomes were collected. R-DSO was performed in 8 patients with no operative or postoperative deaths; 5 underwent decompressing bidirectional Glenn. Left ventricular (LV) poor-compliance was the dominant pathophysiology. Four patients had undergone staged LV recruitment but were not candidates for anatomical biventricular circulation due to LV hypoplasia and/or diastolic dysfunction. 7/8 patients had risk factors for Fontan circulation including pulmonary vein stenosis, pulmonary hypertension, and pulmonary artery stenosis. Median age at R-DSO was 3.7 years (19 months-12 years). All patients were in sinus rhythm at discharge. At median follow-up of 15 months (57 days-4.1 years) no mortalities, reoperations or heart transplants had occurred. All patients had normal morphologic LV systolic function. In one patient, pre-existing pulmonary hypertension (HTN) resolved after R-DSO. Reinterventions included transcatheter mitral valve replacement for residual mitral stenosis and neo-pulmonary balloon valvuloplasty. In 4 patients follow-up catheterization done at a median of 519 days (320 days-4 years) demonstrated median cardiac index of 3.2 L/min/m2 (2.2-4); median sub-pulmonary left ventricular end diastolic pressure was 9 mm Hg (7-15); median inferior vena cava/baffle pressure was 8 mm Hg (7-13). R-DSO is an alternative to anatomical biventricular repair or single ventricle palliation in patients with borderline left hearts and can result in low inferior vena cava pressures and favorable early results. This approach can also relieve pulmonary HTN and allow future transplant candidacy.

Protein-losing enteropathy recurrence after pediatric heart transplantation: Multicenter case series

BACKGROUND

Protein-losing enteropathy (PLE) is a devastating complication of the Fontan circulation. Although orthotopic heart transplantation (HTx) typically results in resolution of PLE symptoms, isolated cases of PLE relapse have been described after HTx.

METHODS

Patients with Fontan-related PLE who had undergone HTx at participating centers and experienced relapse of PLE during follow-up were retrospectively identified. Available data related to pre- and post-HTx characteristics and PLE events were collected.

RESULTS

Eight patients from four different centers were identified. Median time from Fontan procedure to the development of PLE was 8 years, and median age at HTx was 17 years (range 7.7-21). In all patients, PLE resolved at a median time of 1 month after HTx (0.3-5). PLE recurrences occurred at a median time of 7.5 months after HTx (2-132). Each occurrence was associated with one or more significant clinical events; most commonly cellular- or antibody-mediated rejection; and less commonly graft dysfunction, infection, thrombosis, and posttransplant lymphoproliferative disease. PLE recurrences resolved after the successful treatment of the concomitant event, after a median time of 2 months in seven cases, while persisted and recurred in one patient in association with atypical mycobacterium infection and subsequent PTLD onset and relapses. Six patients were alive during follow-up at a median time of 4 years (1.3-22.5) after HTx.

CONCLUSIONS

This is the largest series of PLE recurrence after HTx. All cases were associated with one or more concomitant and significant clinical events. PLE typically resolved after resolution of the inciting clinical event.

Extracardiac manifestations of the Fontan circulation in adults: Beyond the liver

Patients with Fontan circulation are now surviving longer into adulthood and experience a multitude of extracardiac, non-hepatic sequelae that impact their quality of life and prognosis. These sequelae include pulmonary complications (pulmonary vascular disease, sleep-disordered breathing, restrictive lung disease, plastic bronchitis), gastrointestinal manifestations (protein losing enteropathy), chronic venous insufficiency, kidney abnormalities, reproductive issues (pregnancy, contraception and sexual dysfunction), neurocognitive changes, endocrinopathies (glycemic abnormalities, thyroid disorders) and hematological abnormalities (thromboembolic complications and secondary erythrocytosis). This review article aims to present a contemporary overview of the extracardiac, non-hepatic sequelae observed in adults with Fontan circulation.

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.

Protein-losing enteropathy in Fontan circulation: Pathophysiology, outcome and treatment options of a complex condition

Protein-losing enteropathy (PLE) represents a rare but severe and potentially life-threatening complication following Fontan operation in patients with a functional single ventricle. PLE is characterized by enteric protein loss, leading to devastating multiorgan involvement with increased morbidity and mortality. In spite of remarkable advances in the care of congenital heart disease in recent years, treatment of PLE is still one of the most challenging tasks due to limited understanding of the underlying mechanisms and lack of high-quality evidence from large scale, controlled studies to test the real efficacy of the several treatment strategies, which have been proposed. For this reason, we herewith aim to discuss the pathogenesis and diagnosis of PLE in Fontan patients as well as provide a comprehensive overview on potential advantages and disadvantages of the currently available therapeutic strategies, in order to propose a stepwise approach for the management of this unique condition.

Protein losing enteropathy after the Fontan operation

The Fontan or Fontan Kreutzer procedure is the culmination of staged, surgical palliation of functional single ventricle congenital heart disease, offering the potential for survival and good quality of life well into adulthood. As more patients with Fontan circulation age, a variety of complications involving almost every organ system may occur. Protein-losing enteropathy is a major cause of morbidity and mortality after the Fontan operation, occurring more often in patients with adverse hemodynamics and presenting weeks to years after Fontan surgery. The causes are not well understood, but likely include a combination of lymphatic insufficiency, high central venous pressure, loss of heparan sulfate from intestinal epithelial cells, abnormal mesenteric circulation, and intestinal inflammation. A comprehensive evaluation including multimodality imaging and cardiac catheterization is necessary to diagnose and treat any reversible causes. In advanced cases, early referral for heart transplantation evaluation or lymphatic decompression procedures (if the single ventricle function remains adequate) is indicated. Despite the improvement in detection and management options, the mortality remains high. Standardization of protein-losing enteropathy definition and management strategies will help facilitate interpretation of research and clinical experience, potentially fostering the identification of new therapies. Based on the published data, this review suggests a standardized approach to diagnosis and treatment.

Dynamic Contrast Magnetic Resonance Lymphangiography Localizes Lymphatic Leak to the Duodenum in Protein-Losing Enteropathy

OBJECTIVES

Protein-losing enteropathy (PLE) is a disorder of intestinal lymphatic flow resulting in leakage of protein-rich lymph into the gut lumen. Our primary aim was to report the imaging findings of dynamic contrast magnetic resonance lymphangiography (DCMRL) in patients with PLE. Our secondary objective was to use these imaging findings to characterize lymphatic phenotypes.

METHODS

Single-center retrospective cohort study of patients with PLE unrelated to single-ventricle circulation who underwent DCMRL. We report imaging findings of intranodal (IN), intrahepatic (IH), and intramesenteric (IM) access points for DCMRL.

RESULTS

Nineteen patients 0.3-58 years of age (median 1.2 years) underwent 29 DCMRL studies. Primary intestinal lymphangiectasia (PIL) was the most common referring diagnosis (42%). Other etiologies included constrictive pericarditis, thoracic insufficiency syndrome, and genetic disorders. IN-DCMRL demonstrated a normal central lymphatic system in all patients with an intact thoracic duct and localized duodenal leak in one patient (1/19, 5%). IH-DCMRL detected a duodenal leak in 12 of 17 (71%), and IM-DCMRL detected duodenal leak in 5 of 6 (83%). Independent of etiology, lymphatic leak was only visualized in the duodenum.

CONCLUSIONS

In patients with PLE, imaging via DCMRL reveals that leak is localized to the duodenum regardless of etiology. Comprehensive imaging evaluation with three access points can provide detailed information about the site of duodenal leak.

Cardiac Imaging in Patients After Fontan Palliation: Which Test and When?

The Fontan operation represents the final stage of a series of palliative surgical procedures for children born with complex congenital heart disease, where a "usual" biventricular physiology cannot be restored. The palliation results in the direct connection of the systemic venous returns to the pulmonary arterial circulation without an interposed ventricle. In this unique physiology, systemic venous hypertension and intrathoracic pressures changes due to respiratory mechanics play the main role for propelling blood through the pulmonary vasculature. Although the Fontan operation has dramatically improved survival in patients with a single ventricle congenital heart disease, significant morbidity is still a concern. Patients with Fontan physiology are in fact suffering from a multitude of complications mainly due to the increased systemic venous pressure. Consequently, these patients need close clinical and imaging monitoring, where cardiac exams play a key role. In this article, we review the main cardiac imaging modalities available, summarizing their main strengths and limitations in this peculiar setting. The main purpose is to provide a practical approach for all clinicians involved in the care of these patients, even for those less experienced in cardiac imaging.

Non-invasive assessment of liver abnormalities in pediatric Fontan patients

Liver abnormalities are well known among long-term survivors of Fontan palliation, which remains the definite surgery for complex congenital heart disease and single ventricle physiology. Pediatric data however are scarce. We assessed the prevalence and degree of liver abnormalities in pediatric Fontan patients through non-invasive investigations suitable for longitudinal follow-up. Thirty-five patients with a median age of 11.8 years (5.2-16.6) and median time since Fontan of 6 years (1.17-13.83) were studied. Each child underwent a blood test, liver Doppler ultrasound (US), and transient elastography (TE). Healthy children were used as controls for TE measurement. AST, ALT, γGT, and direct bilirubin were abnormal in respectively 12 (34%), 5 (14%), 24 (69%), and 7 (20%) patients, while platelet count was decreased in 7 (20%). Splenomegaly was present in 7 (20%) patients. Portal vein mean flow velocity was < 15 cm/s in 19 (54%) patients indicative of portal hypertension. Twenty-two patients (63%) showed inferior vena cava collapsibility index values below 17%, indicating venous congestion. Hepatic artery and superior mesenteric artery resistance index were inversely correlated with time post Fontan (p < 0.05). TE values in Fontan patients were significantly higher than controls, with a median of 12.6 versus 4.6 kPa (p < 0.001) and were already increased shortly after Fontan completion. Conclusion: Liver abnormalities are frequently observed in pediatric Fontan patients. The non-invasive investigations used were not able to confirm liver fibrosis or differentiate hepatic congestion from fibrosis. Based on our findings, we propose a prospective screening protocol with serial measurements of laboratory, (Doppler) US, and TE parameters. What is Known: • Hepatic dysfunction is a well-known consequence of the Fontan circulation. • The natural history of Fontan-associated liver disease in the pediatric age group remains unclear. What is New: • Liver abnormalities are frequently observed in pediatric Fontan patients; however, differentiating liver fibrosis and hepatic congestion with non-invasive investigations remains challenging. Sonographic Doppler measurements may improve our insight in both Fontan-associated liver disease development and the functioning of the Fontan circulation. • A prospective screening protocol is proposed to improve our ability to detect Fontan-associated liver disease early on and understand its natural history.

Management of circulatory failure after Fontan surgery

With improvement in survival after Fontan surgery resulting in an increasing number of older survivors, there are more patients with a Fontan circulation experiencing circulatory failure each year. Fontan circulatory failure may have a number of underlying etiologies. Once Fontan failure manifests, prognosis is poor, with patient freedom from death or transplant at 10 years of only about 40%. Medical treatments used include traditional heart failure medications such as renin-angiotensin-aldosterone system blockers and beta-blockers, diuretics for symptomatic management, antiarrhythmics for rhythm control, and phosphodiesterase-5 inhibitors to decrease PVR and improve preload. These oral medical therapies are typically not very effective and have little data demonstrating benefit; if there are no surgical or catheter-based interventions to improve the Fontan circulation, patients with severe symptoms often require inotropic medications or mechanical circulatory support. Mechanical circulatory support benefits patients with ventricular dysfunction but may not be as useful in patients with other forms of Fontan failure. Transplant remains the definitive treatment for circulatory failure after Fontan, but patients with a Fontan circulation face many challenges both before and after transplant. There remains significant room and urgent need for improvement in the management and outcomes of patients with circulatory failure after Fontan surgery.

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.

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.

Use of Pulmonary Arterial Hypertension Therapies in Patients with a Fontan Circulation: Current Practice Across the United Kingdom

Background

The Fontan circulation is a successful operative strategy for abolishing cyanosis and chronic volume overload in patients with congenital heart disease with single ventricle physiology. “Fontan failure” is a major cause of poor quality of life and mortality in these patients. We assessed the number and clinical characteristics of adult patients with Fontan physiology receiving pulmonary arterial hypertension (PAH) therapies across specialist centers in the United Kingdom.

Methods and Results

We identified all adult patients with a Fontan‐type circulation under active follow‐up in 10 specialist congenital heart disease centers in England and Scotland between 2009 and 2019. Patients taking PAH therapies were matched to untreated patients. A survey of experts was also performed. Of 1538 patients with Fontan followed in specialist centers, only 76 (4.9%) received PAH therapies during follow‐up. The vast majority (90.8%) were treated with a phosphodiesterase‐5 inhibitor. In 33% of patients, PAH therapies were started after surgery or during hospital admission. In the matched cohort, treated patients were more likely to be significantly limited, have ascites, have a history of protein‐losing enteropathy, or receive loop diuretics (P<0.0001 for all), also reflecting survey responses indicating that failing Fontan is an important treatment target. After a median of 12 months (11–15 months), functional class was more likely to improve in the treated group (P=0.01), with no other changes in clinical parameters or safety issues.

Conclusions

PAH therapies are used in adult patients with Fontan circulation followed in specialist centers, targeting individuals with advanced disease or complications. Follow‐up suggests stabilization of the clinical status after 12 months of therapy.

Predictors of long-term mortality among perioperative survivors of Fontan operation

AIMS

The criteria for 'good' Fontan haemodynamics have been poorly defined in relation to long-term outcomes. The aim of this study was to identify the risk factors for mortality among haemodynamic parameters obtained early after the Fontan operation.

METHODS AND RESULTS

Clinical data of all perioperative survivors of the Fontan operation performed before 2011, from nine institutions, were collected through a retrospective chart review. In total, 1260 patients were included. The median age at the time of Fontan operation was 3.6 years. Post-operative cardiac catheterization was conducted in 1117 patients at a median period of 1.0 years after the operation. During the median follow-up period of 10.2 years, 107 patients died. The mortality rates at 10, 20, and 25 years after the operation were 5%, 12%, and 22%, respectively. On multivariable analysis, older age at the time of the operation {≥15 years, hazard ratio (HR) [95% confidence interval (CI)]: 3.2 (1.7-5.9)} and haemodynamic parameters obtained at post-operative catheterization, such as low ejection fraction [<30%, HR (95% CI): 7.5 (3.2-18)], low systemic oxygen saturation [<80%, HR (95% CI): 3.8 (1.6-9.1)], high central venous pressure [≥16 mmHg, HR (95% CI): 2.3 (1.3-3.9)], and low mean systemic arterial pressure [<60 mmHg, HR (95% CI): 3.0 (1.4-6.2)] were identified as independent predictors of mortality. The predictive model based on these parameters had a c-index of 0.75 at 10 years.

CONCLUSIONS

Haemodynamic parameters obtained at a median period of 1.0 years, post-operatively, can accurately identify patients with a high mortality risk, who may need intensive management to improve long-term outcomes.

KEY QUESTION

What defines 'worse' Fontan haemodynamics?

KEY FINDING

Older age at Fontan (≥15 years), low ejection fraction (<30%), low oxygen saturation (<80%), high central venous pressure (≥16 mmHg), and low mean systemic arterial pressure (<60 mmHg) were identified as independent predictors of mortality.

TAKE HOME MESSAGE

Haemodynamic parameters obtained at a median period of 1.0 years, post-operatively, can accurately identify patients with a high mortality risk, who may need intensive management to improve long-term outcomes.

Protein-losing enteropathy managed with percutaneous enlargement of a restrictive atrial septal defect

Protein-losing enteropathy is one of the most feared complications of the Fontan circulation. The diagnosis of protein-losing enteropathy in this setting should prompt a thorough investigation for the presence of a treatable hemodynamic impairment. In this report, we describe a complete reversal of protein-losing enteropathy following percutaneous enlargement of a restrictive atrial septal defect in a patient with a fenestrated lateral tunnel Fontan and severe mitral stenosis.

In-Vitro Validation of Self-Powered Fontan Circulation for Treatment of Single Ventricle Anomaly

Around 8% of all newborns with a Congenital Heart Defect (CHD) have only a single functioning ventricle. The Fontan operation has served as palliation for this anomaly for decades, but the surgery entails multiple complications, and the survival rate is less than 50% by adulthood. A rapidly testable novel alternative is proposed by creating a bifurcating graft, or Injection Jet Shunt (IJS), used to “entrain” the pulmonary flow and thus provide assistance while reducing the caval pressure. A dynamically scaled Mock Flow Loop (MFL) has been configured to validate this hypothesis. Three IJS nozzles of varying diameters 2, 3, and 4 mm with three aortic anastomosis angles and pulmonary vascular resistance (PVR) reduction have been tested to validate the hypothesis and optimize the caval pressure reduction. The MFL is based on a Lumped-Parameter Model (LPM) of a non-fenestrated Fontan circulation. The best outcome was achieved with the experimental testing of a 3 mm IJS by producing an average caval pressure reduction of more than 5 mmHg while maintaining the clinically acceptable pulmonary flow rate (Qp) to systemic flow rate (Qs) ratio of ~1.5. Furthermore, alteration of the PVR helped in achieving higher caval pressure reduction with the 3 mm IJS at the expense of an increase in Qp/Qs ratio.

T2-Weighted High-Resolution Isotropic Magnetic Resonance Lymphangiography of the Thoracic and Abdominal Lymphatic Vessels with and without Previous High-Fat Meal

RATIONALE AND OBJECTIVES

The aim of this study was to assess the potential benefit of a high-fat meal for preparation of patients before lymphangiography of the thoracic and abdominal lymphatic vessels by a heavily T2-weighted 3D magnetic resonance sequence at 3T.

MATERIALS AND METHODS

A heavily T2-weighted 3D Fast-Spin-Echo sequence was applied twice for lymphangiography in 15 healthy volunteers. One examination was performed following overnight fasting and the second examination was conducted 3 hours after a drinking of 200 ml of cream and a solid meal. The effect of a high-fat meal on the visualization of different segments of the thoracic and abdominal lymphatic vessels was analyzed by scoring of the image quality.

RESULTS

Evaluation of the summarized score of all four segments of the thoracic duct showed significantly improved general visualization of the lymphatic system in the postprandial examination when compared to the results obtained after overnight fasting (mean ± SD: 4.5 ± 1.7 vs. 5.9 ± 1.8, p = 0.007*). Regarding different segments of the lymphatic system significant differences between pre and post cream lymphangiographies were found in the cervical segment (p = 0.012*), the inferior thoracic segment (p = 0.003*) and the abdominal segment (p = 0.035*). In contrast, the visualization of the superior thoracic segment was not significantly improved by high fat meal preparation of the subjects (p = 0.388).

CONCLUSION

A high-fat meal 3 hours prior to T2-weighted MR-lymphangiography improves the visualization of the main lymphatic thoracic and abdominal vessels, particularly the abdominal and cervical part as well as the inferior segment of the thoracic duct.