Protein-losing enteropathy after Fontan operation: resolution after baffle fenestration

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.

The failing Fontan

Nearly 50 years back, Francis Fontan pioneered an operation for tricuspid atresia that bears his name today. The operation has since undergone numerous modifications and continues to be widely applied to an array of single ventricles. Despite restoring normal oxygen levels in the body, the operation creates a neoportal system where adequate cardiac output can be generated only at the expense of increased systemic venous congestion. This results in slow but relentless damage to the end organ systems especially the liver. Continuous surveillance of the patient to monitor this circulation, that will ultimately fail, is of paramount importance. Timely medical and cardiac catheterization and surgical intervention can extend the life span of Fontan patients. Ultimately a change of the hemodynamic circuit in the form of heart transplantation or ventricular assist device will be required to salvage the failing Fontan circuit.

End-organ consequences of the Fontan operation: liver fibrosis, protein-losing enteropathy and plastic bronchitis

The Fontan operation, although part of a life-saving surgical strategy, manifests a variety of end-organ complications and unique morbidities that are being recognised with increasing frequency as patients survive into their second and third decades of life and beyond. Liver fibrosis, protein-losing enteropathy and plastic bronchitis are consequences of a complex physiology involving circulatory insufficiency, inflammation and lymphatic derangement. These conditions are manifest in a chronic, indolent state. Management strategies are emerging, which shed some light on the origins of these complications. A better characterisation of the end-organ consequences of the Fontan circulation is necessary, which can then allow for development of specific methods for treatment. Ideally, the goal is to establish systematic strategies that might reduce or eliminate the development of these potentially life-threatening challenges.

Hypoplastic left heart syndrome: current considerations and expectations

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

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

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

The Fontan pathway: What's down the road?

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

Successful Surgical Treatment of Protein-Losing Enteropathy Complicating Rheumatic Tricuspid Regurgitation

Protein-losing enteropathy may uncommonly complicate cardiac disease. While well described as a complication for patients having undergone previous Fontan surgery for congenital heart disease, pericardial and valvular aetiologies are much less frequent. We report a 35-year-old female presenting with marked hypoalbuminaemia and peripheral oedema on a background of known rheumatic valvular heart disease. After extensive investigation for gastrointestinal, hepatic and renal causes of protein loss, echocardiography demonstrated severe tricuspid valve incompetence. Subsequent invasive testing confirmed severe tricuspid valve regurgitation in the absence of pericardial constriction. The patient proceeded to tricuspid valve repair with resolution of the protein-losing state and correction of hypoalbuminaemia. While cardiac causes of gastrointestinal protein loss are uncommon, they should be considered when initial diagnostic work up is negative. The importance of correction of haemodynamic precipitants of protein-losing enteropathy is also discussed.

Medical management of the failing Fontan

The Fontan operation accomplishes complete separation of systemic venous blood from pulmonary venous circulation in patients with single ventricle anatomy. Operative survival since the first description of the Fontan operation is excellent in the current era through modifications in surgical techniques, identification of patient-specific risk factors, and advances in postoperative care. Improved early outcomes have also resulted in a decline in late mortality for patients who have undergone staged palliation with the Fontan operation. As the number of late survivors from the Fontan operation increases, caregivers will be evermore faced with the challenge of recognizing and managing the patient with failing Fontan physiology. Even after excellent early results, patients with single ventricle lesions remain at risk of progressive ventricular dysfunction, dysrhythmias, progressive hypoxemia, elevated pulmonary vascular resistance, and protein-losing enteropathy, which can result in morbidities including but not limited to, myocardial failure, thromboembolism, and stroke. Consequently, continued long-term survival of patients who undergo the Fontan operation is dependent upon preservation of single ventricle function, avoidance of late complications, and, in the patient with a failing Fontan, recognition and treatment of the underlying pathophysiologic process that has resulted in Fontan failure.

Late complications associated with the Fontan circulation

The recent significant reduction in operative mortality associated with surgical completion of the Fontan circulation is clearly multi-factorial. Better understanding of the fundamental physiological and anatomical issues have led to refinements in operative technique, early neutralization of potential risk factors, widespread use of a staged approach, and selective application of the concept of fenestration or incomplete partitioning. While further reduction of operative mortality is important, and may be anticipated in the future, major emphasis now must be placed on optimizing functional outcome, and understanding and managing the late complications associated with the unique physiology produced by the Fontan circulation.

Long-term follow-up after staged reconstruction or transplantation for patients with functionally univentricular heart

As recently as 35 years ago, children born with a functionally single ventricle were destined to a lifetime of multiple palliative operations, and disrupted growth and development. Physical signs of their cardiac disease were evidenced by chronic hypoxemia, polycythemia, clubbing, small stature, and severely reduced exercise ability. A normal lifestyle, with typical landmarks such as uninterrupted adolescence and potential childbearing, was unlikely. The successful application of right heart bypass by Fontan and Kreutzer in the early 1970s heralded an era of multiple medical and surgical breakthroughs that have systematically improved the quality of life and long-term outlook for these children.

Intestinal protein loss and hypoalbuminemia in children with pneumonia

BACKGROUND

Intestinal protein loss has been reported mainly in diseases affecting the gastrointestinal tract. Intestinal protein loss during pneumonia with effusion has not been reported to date. The authors attempted to assess the associations between pneumonia with effusion and intestinal protein loss and hypoalbuminemia in children.

METHODS

This was a prospective consecutive case series study of in children hospitalized with pneumonia and effusion during a period of 4(1/2) years. Serum albumin, C-reactive protein (CRP), and fecal alpha-1 antitrypsin (alpha-1-AT) were measured in the first 72 hours of hospitalization. Two control groups were studied: one consisted of 50 febrile children hospitalized because of viral or mild bacterial infections, and the other consisted of 20 afebrile children hospitalized because of convulsive disorders.

RESULTS

Sixty-seven children ages 4 months to 14 years hospitalized with pneumonia and effusion were enrolled in the study. Fifty-nine percent (40 children) were found to have elevated fecal alpha-1-AT excretion (range, 2-10 mg/g) compared with none in the two control groups (P < 0.000).Fifty-two percent (35 children) of the children with pneumonia and effusion had mild to moderate hypoalbuminemia (range, 22-34 g/L). Only one child (2%) in the febrile control group had a low albumin of 34 g/L; none were found in the afebrile control group. The level of fecal alpha-1-AT was inversely correlated with serum albumin level.

CONCLUSIONS

Pneumonia with effusion in children is often associated with an intestinal protein loss that can be monitored by measuring gastrointestinal loss of protein, namely fecal alpha-1-AT. In most cases the development of hypoalbuminemia correlates with the development of intestinal protein loss.

Protein-losing enteropathy after Fontan surgery: resolution after cardiac transplantation

Protein-losing enteropathy (PLE), defined as severe loss of serum protein into the intestine, occurs in 4% to 13% of patients after the Fontan procedure. We report a case of PLE reversal after heart transplantation in a 14-year-old boy with Fontan circulation who previously was treated unsuccessfully with medical therapy. The protein loss continued after heart transplantation. We administered total parenteral nutrition to rest the bowel. After 16 months, we observed a gradual decrease in protein loss. The patient is doing well 5 years after heart transplantation and had has a normal serum albumin level.

Fenestration of the Fontan baffle: Benefits and complications

Using a baffle fenestration or adjustable atrial septal defect in a modified Fontan operation is now a common practice. Hemodynamic benefits include increased cardiac index and systemic oxygen transport, as well as lower systemic venous pressure. The incidence and duration of pleural effusions is also reduced by this approach. Potential complications include those associated with the closure mechanism (snare or umbrella) as well as the possibility of paradoxical embolism. This review addresses our current understanding of the risks and benefits of this procedure. Copyright 1998 by W.B. Saunders Company

Effect of fenestration on the sub-diaphragmatic venous hemodynamics in the total-cavopulmonary connection

OBJECTIVE

To understand differences in the sub-diaphragmatic venous physiology between patients with fenestrated and non-fenestrated total-cavopulmonary connections (TCPC).

METHODS

We studied the effects of respiration, retrograde flow, and gravity on the sub-diaphragmatic venous flows in 20 normal healthy volunteers (control), 25 Fontan patients with non-fenestrated TCPC, and 21 with fenestrated TCPC. Subhepatic inferior vena cava (IVC), hepatic vein (HV), and portal vein (PV) flow rates were measured with Doppler ultrasonography during inspiration and expiration in both supine and upright positions. The supine inspiratory-to-expiratory flow rate ratio was calculated to reflect the effect of respiration, the supine-to-upright flow rate ratio was calculated to assess the effect of gravity, and the magnitude of retrograde flow was evaluated with respect to total antegrade flow. Mean IVC, HV, and wedged hepatic venous (WHV) pressures were measured during cardiac catheterization in four TCPC patients before and after fenestration closure. The transhepatic venous pressure gradient (TVPG) was calculated as the difference between the HV and WHV pressure.

RESULTS

Compared with control, HV flow in TCPC was heavily dependent on respiration; this inspiratory capacity was greater in fenestrated than non-fenestrated subjects (inspiratory-to-expiratory flow ratio 1.7, 4.4, and 3.0, respectively P<0.001). Normal retrograde HV flow was diminished in TCPC patients, furthermore, fenestrated subjects had less flow reversal than non-fenestrated (retrograde as percent of antegrade flow 43, 19, and 30%, respectively P<0.001). Gravity decreased IVC and HV flows more in TCPC subjects than control, but this effect was not different between the two TCPC groups. Closure of the fenestration resulted in higher IVC and HV pressures (pre-closure versus post-closure pressures [mmHg]: 11.2 +/- 4.0 vs. 12.3 +/- 3.9, and 11.5 +/- 3.8 vs. 12.4 +/- 3.8, respectively P< or =0.001). The normal TVPG was reduced in fenestrated TCPC, and worsened after fenestration closure (0.9 +/- 0.3 and 0.7 +/- 0.4, respectively P < 0.04).

CONCLUSIONS

Fenestration of the inferior venous connection has important influences on sub-diaphragmatic venous return in TCPC patients. Although fenestration lowers venous pressures and partially restores TVPG, its beneficial effects on flow in TCPC patients are mediated primarily by an increase in inspiration-derived forward HV flow and reduced flow reversal. These observations suggest fenestration results in a more efficient and less congested splanchnic circulation in TCPC patients, and may have important implications in the early and late management of Fontan patients.

Conversion of atriopulmonary or lateral atrial tunnel cavopulmonary anastomosis to extracardiac conduit Fontan modification

OBJECTIVE

Obstruction of the atriopulmonary anastomosis or the lateral atrial tunnel cavopulmonary anastomosis in the Fontan circulation for univentricular physiology may result in dilation of the right atrium or the right atrial free wall that is incorporated in the lateral atrial tunnel, respectively. Secondary detrimental sequelae may consist of supraventricular dysrhythmias, thromboembolism, right pulmonary vein compression, pleural effusions, and protein-losing enteropathy. Conversion of these Fontan connections to an extracardiac conduit cavopulmonary anastomosis may improve central systemic venous flow patterns and provide clinical improvement in these patients.

METHODS

Eighteen patients (7-40 years old) with atriopulmonary anastomosis (n = 15) or obstructed lateral atrial tunnel cavopulmonary anastomosis (n = 3) presented at 5.7 +/- 3.9 years with moderate to severe right atrial dilation (n = 15), Fontan pathway obstruction (n = 12), atrial dysrhythmia (n = 13), pleural effusion (n = 8), right atrial thrombus (n = 3), right pulmonary vein compression (n = 3), and protein-losing enteropathy (n = 3). All patients underwent conversion to an extracardiac conduit cavopulmonary anastomosis.

RESULTS

Two of the three patients with protein-losing enteropathy died (2/18; 11%) on the 30th and 52nd postoperative days. At a mean follow-up of 19 months, the remaining 16 patients had marked (n = 11) or moderate (n = 5) clinical improvement. The SaO2 improved from 90.7 +/- 5.3% to 96.0 +/- 4.1%. None of the patients had obstruction in the systemic venous pathway. In the 13 surviving patients with previous atriopulmonary anastomosis there was a drastic reduction in right atrial size. Four of 13 patients with atrial dysrhythmias converted to sinus rhythm. The right pulmonary vein compression as present in three patients resolved after conversion. Pleural effusions disappeared in four patients.

CONCLUSIONS

Conversion to an extracardiac cavopulmonary connection may lead to clinical improvement in patients with atriopulmonary or lateral atrial tunnel Fontan connection associated with specific target conditions such as obstruction, pulmonary vein compression, right atrial enlargement, atrial dysrhythmia, or atrial thrombus. The conversion operation should not be unduly delayed to prevent irreversible deterioration of clinical status with chronic rhythm disturbances or protein-losing enteropathy. The benefit of the conversion operation is questionable in patients with poor clinical condition and protein-losing enteropathy.

Reversal of protein-losing enteropathy after ligation of systemic-pulmonary shunt

A 21-year-old white woman, born with a univentricular heart, had undergone staged procedures before Fontan correction. She then began to develop edema, protein-losing enteropathy, and ascites refractory to diuretic therapy. Cardiac angiography showed a patent right Blalock-Taussig shunt, with turbulent cavopulmonary circulation. After undergoing an unsuccessful attempt at coil embolization she then underwent shunt ligation, with resolution of symptoms and normalization of protein levels. This report draws attention to the importance of cavopulmonary laminar flow to prevent the development of protein-losing enteropathy.

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

OBJECTIVE

This multicenter study retrospectively analyzes the data on 114 patients with protein-losing enteropathy after Fontan-type surgery. Special attention was given to the different treatment strategies used and their effect on outcome.

METHODS AND RESULTS

In 35 participating centers 3029 Fontan operations were performed. The incidence of protein-losing enteropathy in the survivors was 3.7%. The median age at Fontan-type surgery was 8.2 years (range: 0.6 to 32.9 years). Median age at diagnosis of protein-losing enteropathy was 11.7 years with a median time interval between surgery and diagnosis of 2.7 years (range: 0.1 to 16.4 years). Most patients had edema (79%) and effusions (75%). Hemodynamic data revealed a mean right atrial pressure of 17 +/- SD 5.3 mm Hg with a cardiac index of 2.4 +/- 0.8 L/min/m2. Medical treatment only (n = 52) resulted in a complete resolution of symptoms in 25%, no improvement in 29%, and death in 46%. Surgical treatment (n = 52) was associated with relief of protein-losing enteropathy in 19%, no improvement in 19%, and death in 62%. In 13 patients 16 percutaneous interventions were performed. This resulted in symptomatic improvement after 12 interventions and no improvement after 4 interventions.

CONCLUSIONS

We conclude that the current treatment of protein-losing enteropathy after Fontan operation is associated with a very high mortality and morbidity rate. Preventive strategies and new therapeutic approaches are necessary.

Surgical variations and flow dynamics in cavopulmonary connections: A historical review

Cavopulmonary connections (CPC) have been extensively used in the palliation of complex forms of congenital heart disease requiring some form of right heart bypass. The concept has evolved from unilateral CPC to total CPC (TCPC) in an attempt to prolong the palliated state, but the physiological implications remain only partially understood. We summarize some of the modifications and experimental data and their impact on flow distribution after the Fontan procedure. Copyright 1998 by W.B. Saunders Company

Catastrophic transcatheter baffle fenestration for failing Fontan physiology

Transcatheter fenestration and balloon dilation of an atrial baffle created from native atrial tissue was attempted in a 15-year-old girl with failing Fontan physiology and protein-losing enteropathy. After transseptal puncture, initial dilations with a 10-mm and 12-mm diameter balloon resulted in an inadequate fenestration, with no significant decrease of right atrial pressure or systemic arterial saturation. Dilation of the fenestration with a 16-mm-diameter balloon produced a tear of the atrial septum and subsequent death. Balloon dilation of native atrial tissue may result in uncontrolled tears of the atrial septum.

Reversal of protein-losing enteropathy with heparin therapy in three patients with univentricular hearts and Fontan palliation

We studied three pediatric patients with protein-losing enteropathy in conjunction with univentricular hearts and right atrial to pulmonary artery anastomosis (Fontan operation) before and during heparin therapy. Each patient showed dramatic improvements in symptoms, marked elevations in serum albumin levels, and quantitative reversal of enteric protein loss within a few weeks of beginning therapy. These findings suggest that heparin may be an important treatment for this poorly understood condition.