Severe fetal valvar AS with an abnormal mitral valve (MV) and MR can lead to left heart dilation, with consequent compression of the right ventricle (RV); hydrops and low cardiac output are often associated.
This is a retrospective review of fetuses diagnosed with AS, severe MR, and LA dilation (2002 to 2009) and neonates with the same combination of abnormalities (1988 to 2009).
Fourteen fetuses and 7 neonates were investigated. Eleven fetuses had severe hydrops; all had polyhydramnios and a structurally abnormal MV, abnormal MV inflow pattern, restrictive/intact atrial septum, retrograde flow in the transverse aortic arch, and compression of the right heart. The mean indexed RV output was 326 ± 160 ml/kg/min, lower than the normal average fetal combined ventricular output of 550 ± 150 ml/kg/min. Ten fetuses underwent pre-natal cardiac intervention: aortic valvuloplasty (n = 8) and/or atrial septal dilation/stenting (n = 5). Seven of these, and 11 overall, were live born. Nine patients died (median age 6 days), and 2 patients are currently alive. All 7 patients diagnosed in the neonatal period died (median age 1 day).
Aortic stenosis associated with significant MR in the fetus can cause severe LA and LV enlargement, leading to low cardiac output and hydrops. Despite the potential advantages of early pre-natal diagnosis and both fetal and neonatal interventions, this rare complex of anomalies carries a poor prognosis.