Background: Obstruction of the superior vena cava is one of the potential complications of neonatal extracorporeal membrane oxygenation. Chylothorax is a known complication of surgery involving the thoracic cavity in children, and of extracorporeal membrane oxygenation. The aim of this study was to evaluate the association between chylothorax and superior vena cava obstruction after neonatal extracorporeal membrane oxygenation.
Methods and Results: Twenty-two patients diagnosed with superior vena cava obstruction at ≤6 months of age (median 1.8 months) after neonatal extracorporeal membrane oxygenation were compared with a randomly selected cohort of 44 neonatal extracorporeal membrane oxygenation patients without superior vena cava obstruction. Among patients with superior vena cava obstruction, 18 underwent extracorporeal membrane oxygenation for respiratory disease and four for cardiac insufficiency. Chylothorax was more prevalent among patients with superior vena cava obstruction than controls (odds ratio 9.4 [2.2–40], p = .01) and was associated with extension of obstruction into the left innominate vein. Patients with superior vena cava obstruction were supported by extracorporeal membrane oxygenation for a longer duration than controls. Nineteen patients with superior vena cava obstruction (86%) underwent transcatheter balloon angioplasty and/or stent implantation (median 7 days after diagnosis), which decreased the superior vena cava pressure and superior vena cava-to-right atrium pressure gradient and increased the superior vena cava diameter (all p < 0.001). There were no serious procedural adverse events. Six study patients died within 30 days of the diagnosis of superior vena cava obstruction (including three of nine with chylothorax), which did not differ from controls. During a median follow-up of 2.7 yrs, two additional patients died and nine underwent 14 superior vena cava reinterventions.
Conclusions: Among neonates treated with extracorporeal membrane oxygenation, superior vena cava obstruction is associated with an increased risk of chylothorax. In neonates with chylothorax after extracorporeal membrane oxygenation, evaluation for superior vena cava obstruction may be warranted. Although mortality is high in this population, transcatheter treatment can relieve superior vena cava obstruction and facilitate symptomatic improvement.