Fig. 1

Flowchart of the data used in this study. The data were collected from the Jeonbuk National University Hospital Neonatal Intensive Care Unit from 2014 to 2023 and labeled by a pediatric cardiologist. The labeling criteria to diagnose severe PDA were as follows: a transductal diameter of 1.5 mm or more, or a left atrial diameter:aortic diameter ratio of 1.4:1 or more. Abbreviations: JBUH, Jeonbuk National University Hospital; NICU, Neonatal intensive care unit; CXR, Chest X-ray; sPDA, severe patent ductus arteriosus.