Incidence, Risk Factors, and Outcomes of Chylothorax after Cardiac Procedure in the United States

Background: To examine the epidemiology and risk factors of chylothorax after cardiac procedure in the United States using a contemporary nationally representative database. Methods: We identified postoperative chylothorax events through National Inpatient Sample database (2016 -2019) and compared baseline demographics, comorbidities, and in -hospital outcomes between hospitalizations with and without postoperative chylothorax. The CochraneArmitage test was used to analyze trends in incidence rates. Multivariable Poisson regression models were used to identify potential risk factors for postoperative chylothorax after cardiac procedure. Results: A total of 819 (0.24%) admissions were associated with postoperative chylothorax. The crude and standardized incidence rates of chylothorax were 23.7 (95%CI, 22.1 -25.4) and 61.5 per 10,000 cardiac procedure -related admissions, respectively, with no significant temporal change in incidence rate over the study period (P trend = 0.5249). Infants [adjusted rate ratio (aRR), 117.3, 95% confidence interval (CI), 94.5 -145.5] and children (aRR, 60.2, 95%CI, 48.0 -75.5) were more likely to develop chylothorax compared to adults. Heart and great vessel procedures (aRR, 4.36, 95%CI, 3.61 -5.26), septal repair (aRR, 1.91, 95%CI, 1.58 -2.29), heart transplant (aRR, 5.68, 95%CI, 4.55 -7.10) and pericardial procedures (aRR, 4.04, 95%CI, 3.32 -4.91) were associated with elevated risk for chylothorax. Admissions with chylothorax were associated with higher inpatient mortality (4.9% vs. 3.0%, p< 0.0001), longer inpatient stay, higher costs and greater perioperative complication burden. Conclusions: Following cardiac procedures, chylothorax is an uncommon but serious complication that affects the prognosis. The analysis reveals varying incidence rates across age groups and specific surgical procedures, with infants at elevated risk.