Chylothorax in children with congenital heart disease: incidence of thrombosis.

Postoperative chylothorax is a frequently encountered pathology occurring in up to 4% of patients undergoing surgery for repair of congenital heart disease. Symptomatic thrombosis is associated with chylothorax and may contribute to its severity and duration. Furthermore, vessel thrombosis resulting in persistent vessel occlusion may impede future treatments, diagnostic studies and cardio-surgical interventions. The objective of this study was to determine the incidence of upper system thrombosis in pediatric congenital heart patients with confirmed chylothorax with ultrasound screening of all patients diagnosed with chylothorax. All pediatric patients with confirmed with chylothorax underwent doppler ultrasound of the upper venous system as per hospital standard. This retrospective cohort study enrolled all children between February 1, 2010-August 2012, post cardiac surgery with confirmed chylothorax to determine the incidence of all thrombosis. There were 1396 children who underwent 1396 cardiac surgical procedures during the study time with 760 undergoing cardiopulmonary bypass. Development of chylothorax occurred in 54 of 1396, 3.9% (95%CI 3.0;5.0) procedures in all children. In those children with chylothorax, 28 of 54 episodes, 51.8% (95%CI 38.9;64.6) had confirmed VTE. The 51.8% incidence in this study demonstrates a 2.6 fold increase in risk of thrombosis compared to 20% in children with heart disease and central venous lines and may result in serious clinical consequences. The contribution of upper venous system thrombosis to chylothorax is unknown. Often, clinical suspicion of chylothorax exists, however the lack of a standardized approach to objective diagnosis results in delayed confirmation. Approaches to therapy either treatment of confirmed thrombosis or prevention of thrombosis in patients with chylothorax require formal evaluation. Future studies are urgently needed.