CASE 1:
A girl weighing 2,520 g was born at 37 weeks’ gestation. The patient developed difficulty in breathing, cough, and failure to thrive since the age of 3 months. Her oxygen saturation was 89% in air when she was admitted to our hospital at 4 months. Chest X-ray showed mildly increased diffuse pulmonary infiltrates. An echocardiogram revealed severe pulmonary hypertension and three left-to-right shunts: a small patent ductus arteriosus (PDA), atrial and ventricular septal defect. Chest computed tomography (CT) showed partial atelectasis in the bilateral dorsal region and hyperinflation in the upper lobe (Figure 1a, b). Cardiac catheterization revealed pulmonary arterial pressure of 56/28 mmHg (mean, 37 mmHg) and the ratio of the pulmonary to systemic blood flow (Qp/Qs) was 1.1 in room air. Ambrisentan in addition to her regular dose of sildenafil was started. At the age of 5 months, the patient required intubation, ventilation for more than a month, and inhaled nitric oxide due to bronchiolitis caused by respiratory syncytial virus. Magnetic resonance imaging of the brain demonstrated bilateral PVNH. We performed exome analysis and identified a novel frameshift mutation c.4318delG:p.(Val1440Serfs*6) in FLNA. Sanger sequencing confirmed it was de novo.
The patient was re-intubated and ventilated at 7 months of age due to the sudden onset of desaturation without infection. She underwent PDA ligation with the use of an Amplatzer Vascular Plug device because of exacerbated pulmonary hypertension, pulmonary arterial pressure of 44/25 mmHg (mean, 34 mmHg), and Qp/Qs of 2.6. Her atrial and ventricular septal defects were closed to reduce the risk of increased afterload. The value of N-terminal pro-B-type natriuretic peptide (NT-proBNP) was 6,280 pg/mL when the patient was 5 months old, which decreased to 139 pg/mL following shunt closure, and the chest radiographs improved (Figure 1c-e). Her respiratory condition continued to improve, and she was discharged with high-flow nasal cannula oxygen therapy at the age of 1 year.