Transient Oxygen Desaturation Associated with Persistent Right Venous Valve-Mediated Right-to-Left Atrial Shunt in Term Neonates.

BACKGROUND

Persistent right venous valve (PRVV), a remnant of the fetal right valve of the sinus venosus, may facilitate right-to-left atrial shunting through the patent foramen ovale (PFO). Although PRVV has been reported to cause severe neonatal cyanosis requiring surgical intervention, its clinical significance in otherwise healthy term neonates remains poorly defined.

METHODS

We retrospectively analyzed consecutive term neonates (≥ 37 weeks' gestation) with stable general conditions who exhibited periodic breathing-like oxygen saturation (SpO2) fluctuations and were found to have PRVV-associated right-to-left atrial shunting on transthoracic echocardiography. Clinical characteristics and SpO2 values recorded during routine monitoring were reviewed, and the minimum, median, and maximum SpO2 values during hospitalization were assessed.

RESULTS

Ten term neonates were included. Minimum SpO2 values ranged from 81% to 94% (median, 87%), whereas median SpO2 values remained high (95-100%) in all cases. These desaturation episodes occurred predominantly during sleep and were frequently synchronized with inspiration, suggesting a circulatory rather than respiratory mechanism. Although some neonates experienced transient desaturation reaching as low as 80%, none developed sustained hypoxemia, required prolonged oxygen supplementation, or underwent additional respiratory investigations or therapeutic interventions. All neonates remained clinically stable throughout hospitalization.

CONCLUSION

In otherwise healthy term neonates, PRVV with PFO-related right-to-left atrial shunting may cause transient oxygen desaturation, occasionally reaching as low as 80%; however, it is generally self-limiting and clinically benign. Recognition of this hemodynamic mechanism may help clinicians appropriately interpret transient SpO2 decreases and avoid unnecessary respiratory evaluations in selected neonates.