Background: Pulmonary arteriovenous malformations (PAVMs) are a known complication after some types of cavopulmonary anastomoses (CVPAs). Their cause is unknown, but they may be related to the absence of pulsatile flow or the presence or absence of circulating factors. These PAVMs are diffuse and are presumed to be progressive and irreversible.
Methods and results: All patients with congenital heart disease (CHD) seen at Children's Hospital, Boston, Mass, between 1970 and 1993 were reviewed. We report on the 10 patients with CHD who were found to have developed PAVMs, as diagnosed by cardiac catheterization. Diagnoses included heterotaxy syndrome/polysplenia, with interrupted inferior vena cava and hepatic veins draining to the right atrium (n = 6); heterotaxy/asplenia (n = 1); corrected transposition with pulmonary stenosis (n = 1); and biliary atresia and associated CHD (n = 2). PAVMs were diagnosed 0.1 to 7.0 years (median, 3.5 years) after creation of a CVPA that resulted in exclusion of hepatic venous flow from one or both lungs in 8 of the 10 patients; the remaining 2 patients had normal drainage of hepatic veins to the lungs but had biliary atresia. In all, the common anatomic feature was the exclusion of normal hepatic venous return from the affected pulmonary arterial circulation. All patients with interrupted inferior vena cava, azygous continuation to the superior vena cava, and hepatic veins draining to the right atrium (polysplenia syndrome) were reviewed to determine the incidence of PAVMs in those with CVPA (ie, hepatic venous flow excluded from the pulmonary arteries) and without CVPA. Six of 28 (21%) of those with versus 1 of 56 (1.8%) of those without CVPA developed PAVMs (P = .004). The 1 patient without CVPA who had PAVMs also had biliary atresia. Among patients with CVPA, the probability of developing PAVMs was 15% and 28% at 3 and 5 years, respectively, after CVPA. The histological and angiographic appearances of PAVMs after CVPA are similar to those seen in PAVMs associated with hepatic cirrhosis.
Conclusions: We postulate that PAVMs after CVPA are related to the diversion of normal hepatic venous flow from the pulmonary circulation. In this sense, these PAVMs may be analogous to those associated with liver disease, which have been found to resolve after liver transplantation. Redirection of hepatic flow to the pulmonary bed in some patients with CHD and PAVMs may lead to reversibility of the PAVMs.