Background: Repair of total anomalous pulmonary venous drainage (TAPVD) in neonates remains a challenge. It is associated with a high mortality. We aimed at determining a method for risk stratification of this group of patients., Methods: From 1994 to 2008, 54 patients underwent simple TAPVD operations during the first month of life. Mean pulmonary arterial pressure (PAP), mean systemic arterial pressure (MAP), systolic blood pressure, diastolic blood pressure, central venous pressure, and left atrial pressure were recorded in 44 of the 54 patients for the first 36 hours postoperatively. The remaining 10 patients were excluded because data from invasive pressure monitoring were not available., Results: There were overall 8 deaths (18.2%, 8/44), including 4 (9%, 4/44) early deaths, and 5 reoperations (11.4%, 5/44). The mean PAP was 23.1 ± 6.4 mm Hg, the mean MAP was 50.3 ± 5 mm Hg, and the PAP-to MAP-ratio (PAP/MAP) was 0.80 ± 0.36. By multivariable logistic analysis, the risk factors for mortality were a higher PAP/MAP (p = 0.037) and lower operative weight (p = 0.02). All deaths had either a PAP/MAP of greater than 0.80 or an operative weight of less than 2.5 kg. Hemodynamic index (PAP/MAP divided by operative weight) was predictive of mortality (p = 0.007). Furthermore, the hemodynamic index (p = 0.003) predicted prolonged length of stay in the intensive care unit by regression analysis., Conclusions: The hemodynamic index (PAP/MAP/weight) ≥0.25 in the first 36 hours after TAPVD repair in neonates is predictive of mortality. A higher index predicted longer stay in the intensive care unit. This hemodynamic index may be a useful adjunct for risk stratification in neonates undergoing TAPVD repair., (Copyright © 2012 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)