Postoperative chylothorax following congenital heart surgery: Incidence, risks, therapy, and possible mechanisms

To determine the incidence, risks factors, outcomes, and mechanisms of postoperative chylothorax (PCT) following congenital heart surgery.

Among all patients who underwent congenital heart surgery between 2001 and 2024, those who developed PCT during the same hospitalization were identified. The prevalence of chylothorax was analyzed, along with associated procedures, risk factors, and hemodynamics.

Among 9892 congenital heart surgeries performed during the study period, 312 patients (3.2%) developed PCT. Patients with PCT had a higher proportion of males (64% vs 56%; P = .009), younger age at surgery (median, 0.6 years vs 1.2 years; P < .001), and lower weight at surgery (median, 6.1 kg vs 8.6 kg; P < .001) compared to those without PCT. Regarding surgical types, the most frequently performed operation was the Fontan procedure (20.5%), followed by repair of tetralogy of Fallot (TOF) with atrioventricular septal defect (11.8%), arterial switch operation (ASO), ventricular septal defect (VSD) closure, and aortic arch repair (10.0%). Younger age at operation (P < .001; hazard ratio [HR], 0.745), the Fontan procedure (P < .001; HR, 16.198), ASO, VSD closure, and aortic arch repair (P < .001; HR, 2.835) were strong risk factors for PCT. Postoperative lower mean arterial pressure and higher central venous pressure were associated with PCT in patients following the Fontan procedure and TOF repair.

This large, single-center study of approximately 10,000 congenital heart surgeries reported a 3.2% incidence of PCT. The Fontan procedure had the highest incidence of PCT, followed by complex biventricular repair in neonates and young infants. Early postoperative lower mean arterial pressure and higher central venous pressure may trigger PCT.