Diagnostic value of reversed differential cyanosis in (supra)cardiac total anomalous pulmonary venous return.

Abstract

To investigate the occurrence of reversed differential cyanosis (RDC) in case of (supra)cardiac total anomalous pulmonary venous return (TAPVR), we explored the hemodynamic changes and oxygen saturation levels during the fetal-to-neonatal transition in (supra)cardiac TAPVR, thereby revealing determinant factors of RDC. A computational model was used to simulate the cardiovascular fetal-to-neonatal transition up to 24 h after birth. Abnormalities associated with TAPVR, like patent ductus arteriosus (PDA) and persistent pulmonary hypertension of the neonate (PPHN), were imposed on the model. Hemodynamic impact on flow distribution and right-sided pressures as well as oxygen saturations were assessed. Model findings demonstrated that RDC in (supra)cardiac TAPVR was dependent on two key factors: (1) the type of pulmonary venous connection being supracardiac or cardiac, and (2) the presence of a patent ductus arteriosus exhibiting right-to-left shunting. Persistence of RDC was mainly determined by the latter; an increase in pulmonary-to-systemic pressure difference by PPHN or PDA-induced pulmonary over-circulation contributed to persistence of RDC. This study highlights the significance of RDC in (supra)cardiac TAPVR and suggests to incorporate early screening ( < 24 h after birth) and to consider RDC as an immediate fail in screening protocols to ensure prompt detection of (supra)cardiac TAPVR. Utilizing a validated computational model for the cardiovascular fetal-to-neonatal transition, this study sheds light on the complex hemodynamics in neonates with (supra)cardiac Total Anomalous Pulmonary Venous Return (TAPVR). Model findings suggest that the often-present pulmonary over-circulation in neonates with TAPVR might significantly contribute to the anomaly's frequent omission during pulse-oximetry screening beyond the first 24 h after birth. This study highlights the diagnostic value of reversed differential cyanosis in early screenings within the first 24 h after birth. By including RDC as an immediate fail in early pulse-oximetry screenings, the likelihood of missing (supra)cardiac TAPVR cases could be reduced.