Risk factors of severe chylothorax after cardiac surgery in children

Objective. To identify risk factors of severe chylothorax after cardiac surgery in children. Material and methods. A retrospective study included 84 patients after heart surgery and postoperative chylothorax. Patients underwent surgery between January 2015 and January 2024. Results. The median of age was 0.5 months [0.5; 3.0], body weight — 3.4 kg [3.0; 4.7], ICU-stay — 17 days [11.2; 27.7], mortality — 22.6%. Superior vena cava thrombosis increases the risk of severe chylothorax by 4.14 times (OR 4.14; 95% CI 1.16—3.92; p=0.042), redo surgery — by 2.17 times (OR 2.17; 95% CI 1.09—4.18; p=0.026), aortic arch surgery — by 1.7 times (OR 1.7; 95% CI 0.02—2.81; p=0.027), arterial switch surgery — by 1.9 times (OR 1.9; 1.15—3.76; p=0.038). In chylothorax associated with superior vena cava thrombosis, the risk of death increased by 1.93 times (OR 1.93; 95% CI 1.01—2.67; p=0.006). In patients with genetic pathology, the risk of death increased by 3.71 times (OR 3.71; 95% CI 1.12—4.98; p=0.017). Positive fluid balance (>30 ml/kg) on the first day after surgery increases the risk of death by 1.87 times (OR 1.87; 95% CI 1.16—2.01; p=0.011). Conclusion. Predictors of severe chylothorax are superior vena cava thrombosis, redo cardiac surgery, aortic arch and arterial switch surgery. Superior vena cava thrombosis, genetic diseases and fluid balance >30 ml/kg on the first day after surgery increase the risk of death in patients with chylothorax. Modifiable risk factors of unfavorable outcomes in patients with chylothorax are superior vena cava thrombosis and fluid balance >30 ml/kg on the first day after surgery.