OC181: In utero aortic valvuloplasty for aortic stenosis with evolving hypoplastic left heart syndrome

Aortic stenosis (AS) in the mid-gestation fetus with a normal size or dilated left ventricle (LV) frequently progresses to hypoplastic left heart syndrome (HLHS). Our goal was to determine if prenatal balloon dilation of the aortic valve can increase blood flow through and improve growth and function of the left heart, possibly preventing progression to HLHS. Since 2000, selected fetuses with AS and evolving HLHS have undergone prenatal aortic valvuloplasty. Fetal echocardiographic data were collected prior to the procedure and at regular intervals after the procedure and at birth. Postnatal outcomes were recorded. Between 3/00 and 5/07, 57 fetuses underwent attempted in utero aortic valvuloplasty for critical AS with evolving HLHS at a median gestational age of 23 wks (20–31 wks). The procedure was technically successful in 43 fetuses (75%). Eight pregnancies (14%) did not reach a viable term or preterm birth. Compared with 24 untreated control fetuses, subsequent prenatal growth of the LV, aortic valve, and mitral valve were improved after intervention. Eleven patients were born with or later converted to a biventricular circulation. Multivariable scores were derived for predicting postnatal biventricular outcome on the basis of pre-intervention Z-scores of left heart structures. Technically successful prenatal aortic valvuloplasty alters the growth of left heart structures in fetuses with AS and evolving HLHS. In 29% of cases, this improved growth resulted in a biventricular circulation after birth. Multivariable scoring systems that incorporated LV dimension and aortic annulus Z-scores allow highly sensitive and moderately specific identification of fetuses that survive postnatally with a biventricular circulation.