Ultrasound evaluation of fetal critical aortic stenosis using the left atrium area/cardiac area ratio and the Doppler patterns in the pulmonary veins.

In fetal critical aortic stenosis (AS), a double reverse pattern in the pulmonary veins (PVs) is associated with a poor prognosis. We evaluated the hemodynamic changes using PV Doppler and the left atrium area/cardiac area (LA/CA) ratio in a fetus at 28 weeks of gestation with critical AS complicated with hydrops fetalis, polyhydramnios, and cardiac abnormality. A markedly enlarged LA and severe mitral regurgitation with critical AS were detected, with LA/CA ratio = 0.40 and double reverse pattern with forward/reverse velocity time integral ratio (FRVR) = 1.18 on PV Doppler. After amniotic reduction at 31 weeks, the LA/CA ratio decreased (0.24) and the FRVR in PV increased (7.11). Forward flow through the fetal aorta was seen spontaneously, and hydrops fetalis was relieved with LA volume reduction. A male neonate weighing 2171 g was delivered via cesarean section at 36 weeks with an Apgar score of 5 and 6 at 1 and 5 min, respectively. He required atrial septal opening and bilateral pulmonary artery banding after birth, followed by Norwood operation. The double reverse pattern in PVs might be reversible. The change in FRVR in PVs and LA/CA ratio would be helpful in understanding the hemodynamic change in fetal critical AS.