Pulmonary arteriovenous malformations after a Fontan operation in the left isomerism and absent inferior vena cava.

OBJECTIVE To evaluate the occurrence of pulmonary arteriovenous malformations after a Fontan operation in the left isomerism and absent inferior vena cava. METHODS We retrospectively reviewed 19 patients with the left isomerism and absent inferior vena cava who underwent Fontan operations at our institution. We divided the patients into two groups: bilateral superior vena cava (group A, n=9), and single superior vena cava (group B, n=10). Median age at Fontan operation was 6.2 years (1.0-24.1). Diagnosis of pulmonary arteriovenous malformations was made by pulmonary angiography and bubble contrast echocardiography. RESULTS Median follow-up was 5.3 years (0.2-17.3) with one hospital death. Seven patients suffered from pulmonary arteriovenous malformations. In six out of the seven patients, the occurrence of pulmonary arteriovenous malformations was related to biased pulmonary perfusion of the hepatic venous flow. In group A, the distance between the dominant superior vena cava (which the venous flow from the lower half of the body drains into) and the hepatic venous channel over the distance between the smaller superior vena cava and the hepatic venous channel was larger in patients with pulmonary arteriovenous malformations than in patients without pulmonary arteriovenous malformations (3.83+/-1.28 vs 1.53+/-1.45, p=0.071). In group B, pulmonary arteriovenous malformations developed in two patients whose venous channels did not overlap. Pulmonary arteriovenous malformations developed in only one patient after we changed the hepatic venous channel design to approximate the hepatic venous channel to the dominant superior vena cava as closely as possible. CONCLUSIONS We might prevent pulmonary arteriovenous malformations in patients with the left isomerism and absent inferior vena cava by designing the venous channels to achieve better mixing of the superior vena cava and the hepatic venous flow.