Abstract 4547: Anatomic Predictors of Technical Success and Postnatal Biventricular Outcome after 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). Prenatal balloon aortic valvuloplasty may improve growth and function of the left heart, possibly preventing progression to HLHS Since 2000, we have performed prenatal aortic valvuloplasty in selected fetuses with AS and evolving HLHS. Our experience with this procedure was reviewed, with a focus on left heart growth and postnatal survival with a biventricular circulation. Between 3/00 and 5/07, 57 fetuses underwent attempted aortic valvuloplasty for critical AS with evolving HLHS at a median gestational age of 23 wks. The procedure was technically successful in 43 fetuses (75%). The risk of technical failure was highest in fetuses with a smaller, more globular LV. Compared with 24 untreated control fetuses, subsequent prenatal growth of the LV, aortic valve, and mitral valve were improved after technically successful intervention. Eight pregnancies (14%) did not reach a viable term or preterm birth. Eleven patients were born with or later converted to a biventricular circulation postnatally. Discriminant, logistic regression, and threshold scores were derived that allowed prediction of postnatal biventricular outcome on the basis of Z-scores of left heart structures at the time of intervention. The combination of LV long-axis Z-score <3.6, LV short-axis Z-score <4.6, and aortic annulus Z-score <−2.0 was always associated with univentricular outcome. Technically successful aortic valvuloplasty alters left heart growth in fetuses with AS and evolving HLHS. In 29% of successful cases, this improved growth resulted in a biventricular circulation after birth. Fetal aortic valvuloplasty carries a risk of fetal demise that must be emphasized to prospective candidates. Fetuses without a severely dilated LV and/or a normal sized aortic valve at the time of intervention are poor candidates for in utero aortic valvuloplasty aimed at achieving a biventricular circulation postnatally.