Pulmonary venous Doppler as a marker of restrictive atrial physiology in fetal critical aortic stenosis after fetal valvuloplasty.

Fetal balloon aortic valvuloplasty (fBAV) is performed in carefully selected fetuses with critical aortic stenosis to prevent progression to hypoplastic left heart syndrome. We report a fetus with critical aortic stenosis who underwent successful fBAV at 26 weeks' gestation with restoration of antegrade aortic flow. Serial fetal echocardiography subsequently demonstrated progressive restriction and eventual functional closure of the foramen ovale despite technically successful valvuloplasty. Pulmonary venous Doppler revealed a prominent atrial reversal wave with prolonged reversal duration, while mitral inflow showed marked E-wave predominance, indicating elevated left atrial pressure and severe left ventricular diastolic dysfunction. After birth, the neonate developed pulmonary hypertension physiology with persistently elevated left ventricular end-diastolic pressure despite postnatal balloon aortic valvotomy. This case highlights that pulmonary venous Doppler provides a valuable noninvasive marker of restrictive atrial physiology and may identify fetuses at risk of adverse neonatal hemodynamics despite successful relief of aortic valve obstruction.