Cavopulmonary pathway modification in patients with heterotaxy and newly diagnosed or persistent pulmonary arteriovenous malformations after a modified Fontan operation

Abstract

Pulmonary arteriovenous malformations are an important but uncommon complication of cavopulmonary connection, particularly in patients with heterotaxy. Absence of hepatic venous effluent in pulmonary arterial blood seems to be a predisposing factor. Pulmonary arteriovenous malformations are most common after superior cavopulmonary anastomosis, but may develop, progress, or persist in 1 lung after Fontan completion if hepatic venous blood streams completely or primarily to the contralateral lung. Among 53 patients with heterotaxy and inferior vena cava interruption who underwent a modified Fontan procedure from 1985 to 2005, 8 had unilateral streaming of hepatic venous flow and clinically significant pulmonary arteriovenous malformations after hepatic venous inclusion and underwent reconfiguration of the cavopulmonary pathway. In all 8 patients, the hepatic vein-pulmonary artery pathway was contralateral to and offset from the pulmonary artery anastomosis of the single or dominant superior vena cava. Pathway reconfiguration included pulmonary arterial stenting (n=2), revision of the superior vena cava-pulmonary artery connection (n=1), construction of a branched hepatic vein-pulmonary artery conduit (n=2), and surgical or transcatheter construction of a direct hepatic vein-azygous vein pathway (n=5). Hepatic vein-azygous vein connection led to improvement in 4 of 5 patients; other approaches typically did not lead to improvement. Resolution of hypoxemia after cavopulmonary pathway reconfiguration in patients with unilateral pulmonary arteriovenous malformations and hepatic venous flow-streaming after Fontan completion supports the importance of hepatic venous effluent in the pathogenesis of pulmonary arteriovenous malformations and the practice of cavopulmonary pathway revision in such patients. Completion or reconfiguration of the Fontan circulation with direct hepatic vein-azygous vein connection may provide the most reliable mixing and bilateral distribution of hepatic venous blood in this population of patients.