Chylothorax and pleural effusion in contemporary extracardiac fenestrated fontan completion

Background: We hypothesized that chylothorax could be a sign of intolerance to the Fontan physiology, and thus patients who develop chylothorax or pleural effusion have worse medium-term to long-term survival. Methods: A total of 324 patients who underwent the Fontan operation between 2000 and 2013 were included. Chylothorax was defined as ≥5 mL/kg/day of chylomicron-positive chest drainage fluid no earlier than postoperative day 5 or drainage with >80% lymphocytes. Outcomes were compared between the chylothorax and non-chylothorax groups by the Kaplan–Meier method and log-rank test. Independent predictors of chylothorax and number of days of any chest drainage were analyzed with multivariable logistic regression and multivariable generalized negative binomial regression for count data, respectively. Results: Chylothorax occurred in 78 patients (24%). Compared with the non-chylothorax group, the chylothorax group had a longer duration of chest tube requirement (median, 18 days vs 9 days; P <.000) and a longer length of hospital stay (median, 19 days vs 10 days; P <.000). Eight patients (10.3%) required thoracic duct ligation. The chylothorax group had lower freedom from death (P =.013) and from composite adverse events (P =.021). No predictor was found for chylothorax. Pulmonary atresia (P =.031) and pre-Fontan pulmonary artery pressure (P =.01) were predictive of prolonged pleural effusion (>14 days). Conclusions: Occurrence of chylothorax following the Fontan operation can be a marker of poorer medium-term clinical outcomes. It is difficult to predict occurrence of chylothorax owing to its multifactorial nature and involvement of lymphatic compensatory capacity that is unmasked only after the Fontan operation.