Echocardiographic predictors of neonatal illness severity in fetuses with critical left heart obstruction with intact or restrictive atrial septum.

BACKGROUND

Neonates with critical left heart obstruction and intact atrial septum (IAS) or restrictive atrial septum (RAS) are at risk for hypoxia within hours of birth and remain a group at high risk for mortality.

METHODS

Prenatally diagnosed fetuses with critical left heart obstruction and IAS or RAS with follow-up from January 1, 2005, to February 14, 2017, were included. Primary outcome was a composite measure of severe neonatal illness (pH < 7.15, venous pH < 7.10, bicarbonate < 16 mmol/L, lactic acid > 5 mmol/L, or median oxygen saturation < 60% within 2 hours of birth).

RESULTS

Of 68 live born fetuses, 52 (76.5%) had hypoplastic left heart syndrome, 14 (20.5%) had critical aortic stenosis, and two (3%) had complex anatomy with mitral stenosis/atresia. There were 27 (39.7%) fetuses with IAS and 41 (60.3%) with RAS. Severe neonatal illness was present in 36 (52.9%). The strongest discriminators for severe neonatal illness were a pulmonary vein A:R VTI ≤ 2.7 (P < 0.001, AUC 0.93) and larger pulmonary vein diameter (P = 0.025, AUC 0.77). A:R VTI ≤ 2.7 predicted death or transplant (log-rank P = 0.03).

CONCLUSIONS

In neonates with hypoplastic left heart syndrome and IAS or RAS, A:R VTI ≤ 2.7 is predictive of severe neonatal instability. This threshold can help guide resource planning, delivery management, and improve fetal intervention criteria.