Navigating the Unique Challenge of Pulmonary Hypertension From Left-to-Right PDA Shunts in Two Cases of Congenital Diaphragmatic Hernia.

Pulmonary hypertension (PH) in congenital diaphragmatic hernia (CDH) is nearly universal yet incredibly complex. A patent ductus arteriosus (PDA) is increasingly utilized to both monitor echocardiographically and manage CDH-PH. However, as pulmonary pressures are driven by both vascular resistance and blood flow, there is a risk that as the former improves, PH may in fact worsen from pathologic left-to-right (LtR) PDA shunting. Herein, we describe two cases of neonatal CDH whose PH was complicated by pathologic LtR PDA shunting and pulmonary overcirculation and improved following resolution of the transductal shunt, highlighting the underrecognized risk of pathologic PDA shunts in CDH.