Lymphatic vessel dysplasia is associated with Fontan-associated protein-losing enteropathy. Extra nodal non-Hodgkin lymphomas including mucosa-associated lymphoid tissue (MALT lymphoma) are associated with lymphatic vessel dysplasia. Here, we describe the case of a 7-year-old with Fontan-associated protein-losing enteropathy who developed MALT lymphoma with a clinical course indicative of interaction between these pathologies and improvement in protein-losing enteropathy after MALT lymphoma treatment. This case suggests a pathophysiologic overlap which has implications for the management of Fontan-associated protein-losing enteropathy.

Severe cyanosis due to pulmonary arteriovenous fistulas occurs often after a bidirectional superior cavopulmonary anastomosis (Glenn operation) and also in some congenital anomalies in which hepatic venous blood bypasses the lungs in the first passage. Relocation of hepatic flow into the lungs usually causes these fistulas to disappear. Similar pulmonary arteriovenous fistulas are observed in hereditary haemorrhagic telangiectasia, and in liver disease (hepatopulmonary syndrome). There is no convincing identification yet of a responsible hepatic factor that produces these lesions. Candidates for such a factor are reviewed, and the possibility of angiotensin or bradykinin contributing to the fistulas is discussed.

Pulmonary arteriovenous malformations are a frequent cause of progressive cyanosis after construction of a cavopulmonary anastomosis. Their formation complicates the management of children with single ventricle physiology after a bidirectional Glenn shunt or the Kawashima procedure. The key role of the liver in this phenomenon is suggested by the observation that providing modifications of the Fontan procedure which permit hepatic venous effluent to reach the pulmonary arterial circulation limit further development of the malformations. In addition, it is known that patients with end-stage hepatic failure develop pulmonary arteriovenous malformations that diminish after liver transplantation. We have begun purification of a factor derived from hepatocyte-conditioned media that is inhibitory for the proliferation of cultured endothelial cells. This substance is heat sensitive, and binds avidly to a copper-containing chromatography column. These clinical observations, and this preliminary experimental work, support the concept that hepatic-derived angiogenic factors may play a role in the development of pulmonary arteriovenous malformations after construction of cavopulmonary anastomoses.

To demonstrate the use of transthoracic contrast echocardiography in the detection of pulmonary arteriovenous fistulas in patients with a previously constructed anastomosis between the superior caval vein and the right pulmonary artery (Glenn shunt), and to examine their prevalence in this special population, we evaluated prospectively all patients followed up in the Grown-Up Congenital Heart Unit subsequent to construction of a classical or bi-directional Glenn shunt. We studied 12 patients, aged from 21 to 38 (mean 28 ± 4.8) years who had had a previous cavopulmonary shunt in place for a period of 4 to 33 years (mean 24±9 years). All were examined with cross-sectional contrast echocardiography, 11 patients had cardiac catheterisation and angiography, and 6 patients had magnetic resonance imaging. Systemic arterial oxygen saturations at rest, and during exercise using the modified Bruce protocol, were measured in all patients. Contrast echocardiography showed evidence of pulmonary arteriovenous fistulas in 7 of the 12 patients, with appearance of echo contrast in the left atrium 1–8 seconds after peripheral venous injection in the arm. Simultaneous appearance of microbubbles in the right atrium revealed a residual communication between the superior caval vein and the right atrium in 2 patients, and presence of collaterals between the superior and inferior caval veins in one. Cardiac catheterisation and angiography showed obvious fistulas in 4 patients, and revealed suggestive findings in 2. In patients deemed to have pulmonary arteriovenous fistulas on contrast echocardiography, arterial oxygen saturations at rest (51–94%, mean 75±15.3%) and on exercise (23–91%, mean 53±24.2%) were significantly lower compared to patients judged to be without fistulas (p<0.005). Pulmonary hypertension in the contralateral lung was more common in patients with fistulas (mean left pulmonary arterial pressure 22–110 mm Hg, p=0.014). In patients with cavopulmonary anastomoses, pulmonary arteriovenous fistulas occur frequently in the long term (10–33, mean 25.7±8 years), and are associated with worsening systemic arterial desaturation. Contrast echocardiography should be included in the regular evaluation of these patients as a simple and sensitive technique for the detection of pulmonary arteriovenous fistulas, particularly with the devel opment of increasing cyanosis.

The classical option for surgical repair in patients with congenitally corrected transposition takes advantage of the physiologic correction provided by nature. At the end of the surgical procedures, however, the morphologically right ventricle remains as the systemic ventricle. Surgical intervention is essentially the correction of associated lesions, including closure of ventricular septal defects, pulmonary valvotomy, placement of a conduit from the morphologically left ventricle to the pulmonary arteries, replacement of the morphologically tricuspid valve, and placement of pacemakers for third degree atrioventricular block. For many years, the classical approach was the “standard” surgical approach.1–4 More recently, newer alternatives have become available, including forms of anatomic repair, the “one-and-a half” ventricular option, and conversion to the Fontan circulation. The goal of anatomic repair is to craft connections such that the morphologically left ventricle becomes the systemic ventricle. Surgical techniques that accomplish this are a Rastelli procedure combined with an atrial baffle,5 and the combination of an arterial switch with an atrial baffle, be it a Mustard or Senning procedure.6

Aims: To determine the accuracy of data relating to pulmonary vascular resistance data in patients with a bidirectional Glenn anastomosis as calculated using predicted versus measured uptake of oxygen. Methods: We studied retrospectively the data from 33 patients with a bidirectional Glenn anastomosis who underwent cardiac catheterisation prior to surgery to complete the Fontan circulation. Their weight ranged from 5.4 to 51.7 kg, and they were aged up to 12 years. Uptake of oxygen was measured using the Deltatrac II metabolic monitor. From the calculated indexed pulmonary vascular resistance, cases were stratified according to the risk of failure of the subsequent Fontan circulation. The six patients with a resistance of greater than 4 Um2 were deemed at high risk, the six with a resistance from 3 to 4 Um2 at moderate risk, and the 21 patients with a resistance less than 3 Um2 at low risk. Uptake of oxygen was also estimated from the predictive formulas of Lindahl, Lundell et al. and LaFarge and Miettinen. The indexed resistance was similarly calculated using these formulas and a comparable stratification of risk made from this data. Results: The predicted values for uptake of oxygen were consistently higher than those measured, leading to an underestimation of indexed resistance, with mean difference between −0.62 and −1.57 Um2. This difference resulted in misclassification of between five and nine of the 12 patients considered at moderate or high risk as being at low-risk. No other haemodynamic data could reliably separate the subjects deemed at low-risk from those considered to be at high-risk. A transpulmonary gradient of greater than 7 mm of mercury was found to be 100 percent specific for elevated indexed resistance, but only 60 percent sensitive. Conclusions: In patients with bidirectional Glenn anastomoses, all formulas based on predictive uptake of oxygen lead to underestimation of the true indexed pulmonary vascular resistance, to an extent that could significantly influence clinical decision-making. The transpulmonary gradient is not a reliable surrogate for indexed pulmonary vascular resistance.