Reversed Differential Cyanosis in Two Neonates with Obstructed Supracardiac Total Anomalous Pulmonary Venous Drainage

Generalized cyanosis in newborn can be caused by many pathological conditions and cyanotic congenital heart disease represents one of the important causes. Differential cyanosis refers to the situation where upper limb saturation is higher than lower limb and it is well documented to be caused by persistent pulmonary hypertension in newborn (PPHN) [1] or patients with patent ductus arteriosus and Eisenmenger syndrome in adults [2-4]; Table 1. This has been also reported in a neonate with critical aortic stenosis, hypoplastic aortic arch, pulmonary hypertension and PDA [2]. Reversed differential cyanosis (RDC) refers to the situation when the oxygen saturation of upper limb is lower than that of lower limb, which was classically reported in neonates with transposition of great arteries (TGA) with pulmonary hypertension [2] or TGA with aortic arch obstruction or interruption [5-12]; Table 1. Other causes included supracardiac total anomalous pulmonary venous drainage (TAPVD) [13], isolated right subclavian artery [14], and infants on veno-arterial extracorporeal membrane oxygenation using right carotid artery for cannulation [15]. We herewith reported two cases of obstructed supracardiac TAPVD manifested reversed differential cyanosis.