Venous Properties in a Fontan Patient with Successful Remission of Protein-Losing Enteropathy.

We present the case of a 1-year-old boy who developed protein-losing enteropathy (PLE) within 2 months of a fenestrated Fontan procedure. His fenestration rapidly closed despite bilateral pulmonary stenosis (BPS). Subsequent to PLE onset, both fenestration and the bilateral pulmonary artery were reconstructed, and the patient's PLE had been in remission, with additive use of medications, for more than 2 years. Notably, although fenestration closed again and central venous pressure (CVP) reduction was minimal, the surrogates of venous return resistance were markedly suppressed as shown by increased blood volume, reduced estimated mean circulatory filling pressure, and suppressed CVP augmentation against a contrast agent. Taken together, dynamic characteristics of venous stagnation, rather than the absolute value of CVP, were ameliorated by the pulmonary reconstruction and use of medications, suggesting a significant role of venous property in the physiology of PLE. In addition, simultaneous measures of CVP and ventricular end-diastolic pressure during the abdominal compression procedure suggested a limited therapeutic role of fenestration against PLE in this patient.

Novel Case Report: A Previously Reported, but Pathophysiologically Unexplained, Association Between Collagenous Colitis and Protein-Losing Enteropathy May Be Explained by an Undetected Link with Collagenous Duodenitis.

Collagenous colitis (CC) is associated with non-bloody, watery diarrhea, which is pathophysiologically reasonable because normal colonic absorption (or excretion) of water and electrolytes can be blocked by the abnormally thick collagen layer in CC. However, CC has also been associated with six previous cases of protein-losing enteropathy (PLE), with no pathophysiologic explanation. The colon does not normally absorb (or excrete) amino acids/proteins, which is primarily the function of the small bowel. Collagenous duodenitis (CD) has not been associated with PLE. This work reports a novel case of CD (and CC) associated with PLE; a pathophysiologically reasonable mechanism for CD causing PLE (by the thick collagen layer of CD blocking normal intestinal amino acid absorption); and a novel association of PLE with severe COVID-19 infection (attributed to relative immunosuppression from hypoproteinemia, hypoalbuminemia, hypogammaglobulinemia, and malnutrition from PLE).

Treatment strategies for protein-losing enteropathy in Fontan-palliated patients.

OBJECTIVE: Protein-losing enteropathy is an infrequent but severe condition occurring after Fontan procedure. The multifactorial pathogenesis remains unclear and no single proposed treatment strategy has proven universally successful. Therefore, we sought to describe different treatment strategies and their effect on clinical outcome and mortality. MATERIAL AND METHODS: We performed a retrospective observational study. From the total cohort of 439 Fontan patients treated in our institution during the study period 1986-2019, 30 patients (6.8%) with protein-losing enteropathy were identified. Perioperative, clinical, echocardiographic, laboratory, and invasive haemodynamic findings and treatment details were analysed. RESULTS: Median follow-up after disease onset was 13.1 years [interquartile range 10.6]. Twenty-five patients received surgical or interventional treatment for haemodynamic restrictions. Medical treatment, predominantly pulmonary vasodilator and/or systemic anti-inflammatory therapy with budesonide, was initiated in 28 patients. In 15 patients, a stable remission could be achieved by medical or surgical procedures (n = 3 each), by combined multimodal therapy (n = 8), or ultimately by cardiac transplantation (n = 1). Phrenic palsy, bradyarrhythmia, Fontan pathway stenosis, and absence of a fenestration were significantly associated with development of protein-losing enteropathy (p = 0.001-0.48). Ten patients (33.3%) died during follow-up; 5-year survival estimate was 96.1%. In unadjusted analysis, medical therapy with budesonide and pulmonary vasodilator therapy in combination was associated with improved survival. CONCLUSIONS: Protein-losing enteropathy is a serious condition limiting survival after the Fontan procedure. Comprehensive assessment and individual treatment strategies are mandatory to achieve best possible outcome. Nevertheless, relapse is frequent and long-term mortality substantial. Cardiac transplantation should be considered early as treatment option.

Protein-losing enteropathy.

PURPOSE OF REVIEW: The present review offers its readers a practical overview of protein-losing enteropathy, particularly with regard to diagnostic and therapeutic approaches. The aim is to support clinicians in their daily practice with a practical tool to deal with protein-losing enteropathy. RECENT FINDINGS: The literature covering protein-losing enteropathy does not appear to be quite recent and also guidelines are scanty. The main innovations during the last decade probably regard the introduction of enteroscopic techniques in the diagnostic flowchart. The use of video-capsule and device-assisted enteroscopy has enabled the direct exploration of the small bowel and the identification of the damage causing the loss of proteins from the gastrointestinal tract. Other innovations are to do with the therapies of the disorder underlying protein-losing enteropathy, although the support with nutritional supplementation are the direct remedies to tackle the protein loss. SUMMARY: Protein-losing enteropathy represents an important clinical aspect of different gastrointestinal and extra-intestinal diseases. An established flowchart is still unavailable, but the use of enteroscopy has deeply changed the modern diagnostic approach. Nutritional support and therapy of the underlying disease are pivotal to patients' management.

Decompression of the thoracic duct: A novel transcatheter approach.

In patients with total cavopulmonary connections, elevated central venous pressures (CVP) have detrimental effects on the lymphatic system causing an imbalance in fluid production and drainage of the interstitium. This combination may result in life-threatening lymphatic complications including plastic bronchitis (PB), protein losing enteropathy (PLE), chylothorax, and ascites. While embolization of the abnormal lymphatics has greatly improved outcomes from these complications, alternative treatment strategies have been proposed that would result in improved lymphatic drainage while leaving the lymphatic system intact. We report two novel transcatheter approaches for thoracic duct (TD) decompression in two patients who developed PLE after completion of the Fontan procedure as part of staged palliation for congenital heart disease. In addition, one patient had severe concurrent PB. In both patients, a connection was created between a left superior vena cava (LSVC) to the left atrium allowing for a nonsurgical method to decompress the TD. This procedure resulted in significant clinical and laboratory improvement of both patients' PLE and other symptoms of lymphatic dysfunction.

Protein-Losing Enteropathy Following Fontan Palliation.

Protein-losing enteropathy (PLE) is a chronic condition involving multiple organ systems that may develop any time following Fontan completion. The pathogenesis of PLE is complex and multifactorial. Chronic venous hypertension, low cardiac output, and abnormal lymphatics may all play a role in the pathogenesis of PLE. Common signs and symptoms include chronic diarrhea, abdominal pain, and ascites. Diagnosis is based on the presence of signs and symptoms in addition to hypoalbuminemia and elevated stool alpha 1 antitrypsin. Early identification and a comprehensive approach to evaluation and treatment are important, as they may affect survival. The initial evaluation should include cardiac catheterization for hemodynamic assessment. Although an evidence base for treatment is lacking, various medical, interventional, and surgical approaches have been described with variable degrees of success. Commonly used therapies include nutritional support, diuretics, subcutaneous unfractionated heparin, budesonide, and sildenafil. Limited data exist for Fontan conversion or takedown. Assessment for heart transplantation should be considered. PLE mortality is high-approximately 50%-but may be mitigated by aggressive investigation and management. The evolving understanding of the role of lymphatics in the pathophysiology of PLE and the emerging role of interventional lymphatic procedures may further improve outcomes in this patient population.

Comparative pathophysiology and management of protein-losing enteropathy.

Protein-losing enteropathy, or PLE, is not a disease but a syndrome that develops in numerous disease states of differing etiologies and often involving the lymphatic system, such as lymphangiectasia and lymphangitis in dogs. The pathophysiology of lymphatic disease is incompletely understood, and the disease is challenging to manage. Understanding of PLE mechanisms requires knowledge of lymphatic system structure and function, which are reviewed here. The mechanisms of enteric protein loss in PLE are identical in dogs and people, irrespective of the underlying cause. In people, PLE is usually associated with primary intestinal lymphangiectasia, suspected to arise from genetic susceptibility, or "idiopathic" lymphatic vascular obstruction. In dogs, PLE is most often a feature of inflammatory bowel disease (IBD), and less frequently intestinal lymphangiectasia, although it is not proven which process is the true driving defect. In cats, PLE is relatively rare. Review of the veterinary literature (1977-2018) reveals that PLE was life-ending in 54.2% of dogs compared to published disease-associated deaths in IBD of <20%, implying that PLE is not merely a continuum of IBD spectrum pathophysiology. In people, diet is the cornerstone of management, whereas dogs are often treated with immunosuppression for causes of PLE including lymphangiectasia, lymphangitis, and crypt disease. Currently, however, there is no scientific, extrapolated, or evidence-based support for an autoimmune or immune-mediated mechanism. Moreover, people with PLE have disease-associated loss of immune function, including lymphopenia, severe CD4+ T-cell depletion, and negative vaccinal titers. Comparison of PLE in people and dogs is undertaken here, and theories in treatment of PLE are presented.

Atypical Clinical Presentation of Crohn's Disease with Superior Mesenteric Vein Obstruction and Protein-losing Enteropathy.

We herein report a 44-year-old man suffering from systemic edema due to protein-losing enteropathy (PLE) with superior mesenteric vein (SMV) obstruction and development of collateral veins, which subsequently proved to be a chronic result of thrombosis and a complication of Crohn's disease (CD). PLE was supposedly induced by both intestinal erosion and thrombosis-related lymphangiectasia, which was histologically proven in his surgically-resected ileal stenosis. Elemental diet and anti-TNFα agent improved his hypoalbuminemia after surgery. The rarity of the simultaneous coexistence of SMV obstruction and PLE and the precedence of these complications over typical abdominal symptoms of CD made the clinical course complex.

Successful Treatment of Protein-Losing Enteropathy and Plastic Bronchitis by Biphasic Cuirass Ventilation in a Patient with Failing Fontan Circulation.

We present a 16-year-old male patient with hypoplastic left heart syndrome who developed protein-losing enteropathy (PLE) and plastic bronchitis (PB) after a Fontan operation. He received medical therapies, including albumin infusion, unfractionated heparin, and high-dose anti-aldosterone therapy but could not obtain clinical relief. Biphasic cuirass ventilation (BCV) led to expectoration of bronchial casts and prompt resolution of PB. Notably, clinical symptoms related to PLE were dramatically improved after starting BCV. A brief period of BCV increased stroke volume from 26±1.4 to 39±4.0 mL. This case suggests that BCV could be an effective treatment for PLE in patients with failing Fontan circulation.

Protein-Amino Acid Metabolism Disarrangements: The Hidden Enemy of Chronic Age-Related Conditions.

Proteins are macro-molecules crucial for cell life, which are made up of amino acids (AAs). In healthy people, protein synthesis and degradation are well balanced. However, in the presence of hypercatabolic stimulation (i.e., inflammation), protein breakdown increases as the resulting AAs are consumed for metabolic proposes. Indeed, AAs are biochemical totipotent molecules which, when deaminated, can be transformed into energy, lipids, carbohydrates, and/or biochemical intermediates of fundamental cycles, such as the Krebs' cycle. The biochemical consequence of hyper-catabolism is protein disarrangement, clinically evident with signs such as sarcopenia, hypalbuminemia, anaemia, infection, and altered fluid compartmentation, etc. Hypercatabolic protein disarrangement (HPD) is often underestimated by clinicians, despite correlating with increased mortality, hospitalization, and morbidity quite independent of the primary disease. Simple, cheap, repeatable measurements can be used to identify HPD. Therefore, identification and treatment of proteins' metabolic impairment with appropriate measurements and therapy is a clinical strategy that could improve the prognosis of patients with acute/chronic hypercatabolic inflammatory disease. Here, we describe the metabolism of protein and AAs in hypercatabolic syndrome, illustrating the clinical impact of protein disarrangement. We also illustrate simple, cheap, repeatable, and worldwide available measurements to identify these conditions. Finally, we provide scientific evidence for HPD nutritional treatment.

Echocardiographic characteristics in Fontan patients before the onset of protein-losing enteropathy or plastic bronchitis.

BACKGROUND: It was this study's objective to evaluate the echocardiographic characteristics and flow patterns in abdominal arteries of Fontan patients before the onset of protein-losing enteropathy (PLE) or plastic bronchitis (PB). DESIGN: In this retrospective cohort investigation, we examined 170 Fontan patients from 32 different centers who had undergone echocardiographic and Doppler ultrasound examinations between June 2006 and May 2013. Follow-up questionnaires were completed by 105 patients a median of 5.3 (1.5-8.5) years later to evaluate whether one of the complications had occurred since the examinations. RESULTS: A total of 91 patients never developed PLE or PB ("non-PLE/PB"); they were compared to 14 affected patients. Eight of the 14 patients had already been diagnosed with "present PLE/PB" when examined. Six "future PLE/PB" patients developed those complications later on and were identified on follow-up. The "future PLE/PB" patients presented significantly slower diastolic flow velocities in the celiac artery (0.1 (0.1-0.5) m/s vs 0.3 (0.1-1.0) m/s (P = .04) and in the superior mesenteric artery (0.0 (0.0-0.2) m/s vs 0.2 (0.0-0.6) m/s, P = .02) than the "non-PLE/PB" group. Median resistance indices in the celiac artery were significantly higher (0.9 (0.8-0.9) m/s vs 0.8 (0.6-0.9) m/s, (P = .01)) even before the onset of PLE or PB. CONCLUSION: An elevated flow resistance in the celiac artery may prevail in Fontan patients before the clinical manifestation of PLE or PB.

Protein-losing enteropathy in biventricular circulation precipitated by mild stenosis of the inferior caval vein in conjunction with total occlusion of the superior caval vein: a word of caution.

We report the case of a young boy with a history of total occlusion of the superior caval vein, diagnosed early after complex neonatal cardiac surgery, who developed severe protein-losing enteropathy. Protein-losing enteropathy was precipitated by a relatively mild stenosis at the junction of the inferior caval vein with the right atrium. Percutaneous stent dilation of the veno-atrial junction definitively relieved the stenosis, and the protein-losing enteropathy subsequently resolved.

Inflammatory bowel disease versus chronic enteropathy in dogs: are they one and the same?

The aim of this review is to discuss why "chronic enteropathy" might be a better term than "inflammatory bowel disease" in dogs, because the treatment and outcome of the disease is very different from that of inflammatory bowel disease in humans. The effect of food, antibiotics and immunosuppressant drugs on chronic enteropathy will be reviewed. New treatments under investigation will also be introduced. Although there are several studies evaluating treatment of chronic enteropathy in dogs, the quality and quantity of evidence supporting individual therapies remains scarce and more work is needed to improve management of this disease. Finally, new findings about dogs with chronic enteropathy complicated by protein-losing enteropathy will be discussed. Although prognosis for these dogs is poor, recent data might help improve their treatment.

Assessment of intestinal malabsorption.

Significant efforts have been made in the last decade to either standardize the available tests for intestinal malabsorption or to develop new, more simple and reliable techniques. The quest is still on and, unfortunately, clinical practice has not dramatically changed. The investigation of intestinal malabsorption is directed by the patient's history and baseline tests. Endoscopy and small bowel biopsies play a major role although non-invasive tests are favored and often performed early on the diagnostic algorithm, especially in paediatric and fragile elderly patients. The current clinically available methods and research tools are summarized in this review article.

Proposal for Prevention or Alleviation of Protein/Lymph-Losing Enteropathy (PLE/LLE) After Fontan Circulation Treatment of Univentricular Hearts: Restoration of Lymph Balance With a "Lymphatic Right-to-Left Shunt."

In Fontan circulations created for univentricular hearts, systemic venous return is diverted to the lungs before returning to the heart. The Total Cavopulmonary Connection (TCPC) is often the preferred surgical procedure whereby a 4-way anastomosis is created with inflow from the superior vena cava (SVC) and inferior vena cava (IVC) and outflow to the right and left branches of the pulmonary artery. In this arrangement, the systemic venous pressure must be elevated sufficiently to perfuse the lungs passively without the normal boost of the right ventricle. Hence, unlike surgical corrections for other congenital heart conditions, the systemic venous pressures in a Fontan circuit must be elevated to make the circulation work. It is proposed here that the incidence of PLE/LLE is directly related to elevated venous and lymphatic pressures, which cause leakage of proteins/lymph into the gastrointestinal tract (GIT) and expulsion from the body. It is commonly held that elevated venous pressures are relatively better tolerated in the upper body, but much less so in the heptatosplanchnic circulation and the lower body. It is also well established that elevated venous pressure increases lymph formation, most of which is produced in the hepatosplanchnic region (liver and intestine). It is further argued here that the increase in lymph filling pressure arising from the higher lymph flow, in association with the backpressure exerted by elevated venous pressure at the main drainage point into the venous system, results in a substantial increase in pressure in the thoracic duct. This pressure is transmitted back to the intestinal lymphatics, causing dilatation with lacteal rupture and protein or bulk lymph leakage into the intestine. We propose in this paper a new approach, based on experimental evidence, to prevent and/or alleviate this condition by draining or redirecting the thoracic duct (or, alternatively, a more localized intestinal lymphatic vessel) into one of the pulmonary veins or the left atrium, which are typically at near-normal pressure in a Fontan circulation. This "lymphatic-venous right-to-left" shunt maneuver would significantly reduce the venous backpressure on the lymphatics as well as improve lymph circulation, resulting in a decrease in the intestinal lymphatic pressure and thereby prevent or alleviate protein/lymph loss, i.e. lymph balance would be restored. Moreover, the greatly facilitated lymphatic flow would encourage further capillary filtration to relieve excessive venous pressure in the hepatosplanchnic region and protect the liver and kidneys. This paper is intended as a discussion document for elicitation of comments on the soundness and viability of this proposal as well as on technical challenges and steps to explore and advance it.

Early Impact of Fontan Operation on Enteric Protein Loss.

BACKGROUND: Protein-losing enteropathy (PLE) is a challenging complication after a Fontan operation. Subclinical enteric protein loss may precede development of overt PLE. We evaluated the acute effects of Fontan circulation on enteric protein loss and mesenteric vascular resistance. METHODS: A prospective cohort study was performed evaluating enteric protein loss in children undergoing Fontan operations. Stool alpha-1 antitrypsin (A1AT) concentration was measured in the preoperative, early postoperative, and intermediate postoperative (3-9 months) periods. The intestinal circulation was characterized by Doppler-derived resistance indices of the superior mesenteric artery (SMA), and serum albumin and protein levels were obtained. RESULTS: We enrolled 33 participants at a median age at operation of 3.0 years (interquartile range [IQR], 2.5-3.3 years). No clinical PLE was observed. Six of the 93 stool samples obtained had elevated A1AT levels (>54 mg/dL), with 2 abnormal samples at each of the 3 time points. Two of the 5 participants with elevated stool A1AT values had significant hemodynamic disturbances requiring intervention (junctional bradycardia or tricuspid stenosis). There was no difference in SMA resistance in the preoperative versus early postoperative periods (p = 0.9). Serum albumin levels were lower in the early postoperative period compared with the preoperative period (3.2 mg/dL [{IQR}, 2.9-3.5] versus 4.1 mg/dL; IQR, 3.4-4.5; p = 0.01) but did not correlate with abnormal stool A1AT concentration or SMA resistance indices. CONCLUSIONS: The Fontan operation does not commonly result in acute development of increased enteric protein loss. However, increased enteric protein loss may occur in children before or after a Fontan operation, particularly when hemodynamic disturbances are present.

Prognostic factors in dogs with protein-losing enteropathy.

Canine protein-losing enteropathy (PLE) is associated with severe gastrointestinal disorders and has a guarded to poor prognosis although little information is available regarding factors affecting prognosis. The purpose of this study was to identify the prognostic factors for survival of dogs with PLE. Ninety-two dogs diagnosed with PLE from 2006 to 2011 were included in a retrospective cohort study. Survival analysis was performed using the Kaplan-Meier method and log-rank test. Variables recorded at the time of diagnosis were statistically analysed for possible prognostic factors in a univariate and multivariate Cox proportional hazard model. In the multivariate analysis, the predictors for mortality in dogs with PLE were more highly scored in terms of canine inflammatory bowel disease activity index (CIBDAI) (P = 0.0003), clonal rearrangement of lymphocyte antigen receptor genes (P = 0.003), and elevation of blood urea nitrogen (BUN) (P = 0.03). Using histopathological diagnosis, both small- and large-cell lymphomas were associated with significantly shorter survival times than chronic enteritis (CE) and intestinal lymphangiectasia (IL). Normalization of CIBDAI and plasma albumin concentration within 50 days of initial treatment was associated with a longer survival time. In conclusion, CIBDAI, clonal rearrangement of lymphocyte antigen receptor genes, histopathological diagnosis, and response to initial treatments would be valuable in separating the underlying causes and could be important in predicting prognosis in dogs with PLE.

Linfangiectasia intestinal primaria como causa de hipoalbuminemia / Primary intestinal lymphangiectasia as a cause of hypoalbuminemia

La linfangiectasia intestinal primaria es una malformación congénita de los vasos linfáticos subserosos asociada a una enteropatía pierde-proteínas. La obstrucción del drenaje linfático del intestino origina una rotura de los vasos linfáticos intestinales con salida de linfa hacia la luz intestinal, lo que causa edemas por hipoproteinemia, inmunodeficiencia por hipogammaglobulinemia, linfopenia y esteatorrea. Presentamos el caso clínico de un lactante de 6 meses con infecciones graves, hipoalbuminemia, edemas y esteatorrea, en el que se confirmó el diagnóstico de linfangiectasia intestinal por biopsia intestinal y se descartó una causa desencadenante mediante otras pruebas complementarias (AU)

Primary intestinal lymphangiectasia is a congenital malformation of the subserosal lymph vessels associated to a protein-losing enteropathy. The obstruction of the lymphatic drainage of the intestine leads to a rupture of the intestinal lymph vessels in which the lymph spreads to the intestinal lumen, which causes hypoproteinemia-related edemas, hypogammaglobulinemia-related immunodeficiency, lymphocytopenia and steatorrhea. We present a clinical case of a lactating 6-months old infant with severe infections, hypoalbuminemia, edemas and steatorrhea in which an intestinal biopsy confirmed the diagnosis of intestinal lymphangiectasia and a triggering cause was ruled out with other complementary tests (AU)