Abstract
Abnormal pulmonary venous flow patterns on fetal echocardiography and a nutmeg lung pattern on fetal magnetic resonance imaging are seen in patients with pulmonary venous stenosis. The association between these findings and the degree of pulmonary venous stenosis remains unknown. We report an extremely rare case of a fetus diagnosed with hypoplastic left heart syndrome complicated by an absent atrial septum and supracardiac total anomalous pulmonary venous connection with left pulmonary venous congestion. This case suggests that compared to non-pulsatile continuous pulmonary venous flow, the nutmeg lung pattern can only be observed with severe pulmonary congestion and advanced pulmonary lymphangiectasia.
Keywords: case report, hypoplastic left heart syndrome, absent atrial septum, supracardiac total anomalous pulmonary venous connection
Introduction
Hypoplastic left heart syndrome is rarely complicated by the absence of an atrial septum.1 In addition, the incidence of complications of total anomalous pulmonary venous connection (TAPVC) in patients with hypoplastic left heart syndrome is low (2.3%), and the prognosis is poor. The prognosis may even be poorer if the condition is further complicated by pulmonary venous stenosis.2,3
The nutmeg lung pattern refers to the heterogeneous appearance of the lung parenchyma, identified as the presence of subtle T2-hyperintense branching tubular structures that emanate from the hila on fetal magnetic resonance imaging (MRI). Previous studies have shown that this pattern suggests the presence of pulmonary lymphangiectasia and, in relation to congenital heart disease, may be considered indicative of secondary lymphangiectasia caused by pulmonary venous congestion.4,5 However, few studies have investigated this condition. The association of the nutmeg lung pattern with the degree of pulmonary congestion and prognosis remains unclear. This study reports an extremely rare case of hypoplastic left heart syndrome complicated by an absent atrial septum and a mixed form of supracardiac TAPVC accompanied by pulmonary venous stenosis. This article discusses fetal echocardiographic and MRI findings as well as the postnatal course of the neonate.