Prominent Eustachian Valve in Newborns: A Report of Four Cases

Abstract

The Eustachian valve (EV) is located in the superior portion of the inferior vena cava (IVC) and protrudes into the right atrial cavity. It is considered to be a functional valve in the fetus that helps direct oxygenated blood from the IVC toward the foramen ovale, thereby bypassing the pulmonary circulation. 1 After birth and upon closure of the foramen ovale, the valve has no particular function and tends to regress. There is a large variability in the nature and characteristics of the EV in regards to shape, size, thickness, texture, and length. 1,2 Historically, a prominent EV is essentially benign in nature and requires no treatment. However, it can cause significant intracardiac shunting of deoxygenated blood from right-to-left atrium. In this report, we present clinical case vignettes of four newborn infants who were admitted to the neonatal intensive care unit (NICU) with cyanosis and oxygen (O 2) desaturation. They were all found to have prominent EV with significant intracardiac right-to-left shunting. Case 1 A 3.15 kg term female newborn was admitted to the NICU due to cyanosis and stridor while crying. She was born via vacuum-assisted vaginal delivery. Her mother had gestational diabetes treated with glyburide. Prolonged fetal decelerations were recorded during external fetal heart rate monitoring. At birth, the baby required positive pressure ventilation for 60 seconds and was assigned Apgar scores of 5 and 8 at 1 and 5 minutes, respectively. At 26 hours of life, the baby was observed to turn pale with crying. The baby was placed on a pulse oximeter, and with crying, would desaturate to the low 70s. Saturations would return to the high 90s immediately upon the administration of 2 L of free flow O 2. When not agitated, her saturations on room air were 95 to 100%. On examination, she was noted to have circumoral cyanosis, as well as stridor with suprasternal retractions apparent only when she was crying. Mild micrognathia was also noted. Airway and lungs were clear on chest X-ray (CXR) and without consolidations, atelectasis, pneumothorax, or pleural effu-sion. Echocardiography (Echo) showed normal anatomy with good left ventricular (LV) function. A prominent EV was visible, causing blood to shunt right-to-left from the IVC to the left atrium (LA). A patent foramen ovale (PFO) was present with intermittent right-to-left shunting mainly in diastole (►Fig. 1). Echo study also ruled out the Chiari network (CN) and cor triatriatum dexter (CTD). No other anomaly seen and the coronary sinus ostium looked normal. No other Keywords ► Eustachian valve ► newborn ► cyanosis ► echocardiogram ► infant Abstract The Eustachian valve (EV) is an embryological remnant of the inferior vena cava that during fetal life helps divert oxygenated blood from the IVC toward the foramen ovale to escape the pulmonary circulation. This remnant usually regresses after birth and is considered a benign finding in the majority of cases. However, EV can lead to complications in the neonatal period or later in life. In this short case series, we present four newborn infants with prominent EV who were symptomatic after birth and required admission to the neonatal intensive care unit.