Balloon dilation of severe aortic stenosis in the fetus: potential for prevention of hypoplastic left heart syndrome: candidate selection, technique, and results of successful intervention.
BACKGROUND
Preventing the progression of fetal aortic stenosis (AS) to hypoplastic left heart syndrome (HLHS) requires identification of fetuses with salvageable left hearts who would progress to HLHS if left untreated, a successful in utero valvotomy, and demonstration that a successful valvotomy promotes left heart growth in utero. Fetuses meeting the first criterion are undefined, and previous reports of fetal AS dilation have not evaluated the impact of intervention on in utero growth of left heart structures.


RESULTS
We offered fetal AS dilation to 24 mothers whose fetuses had AS. At least 3 echocardiographers assigned a high probability that all 24 fetuses would progress to HLHS if left untreated. Twenty (21 to 29 weeks' gestation) underwent attempted AS dilation, with technical success in 14. Ideal fetal positioning for cannula puncture site and course of the needle (with or without laparotomy) proved to be necessary for procedural success. Serial fetal echocardiograms after intervention demonstrated growth arrest of the left heart structures in unsuccessful cases and in those who declined the procedure, while ongoing left heart growth was seen in successful cases. Resumed left heart growth led to a 2-ventricle circulation at birth in 3 babies.


CONCLUSIONS
Fetal echocardiography can identify midgestation fetuses with AS who are at high risk for developing HLHS. Timely and successful aortic valve dilation requires ideal fetal and cannula positioning, prevents left heart growth arrest, and may result in normal ventricular anatomy and function at birth.
Tworetzky
Wayne
W
Department of Cardiology, Children's Hospital Boston, 300 Longwood Ave, Boston MA 02115, USA. wayne.tworetzky@cardio.chboston.org
Wilkins-Haug
Louise
L
Jennings
Russell W
RW
van der Velde
Mary E
ME
Marshall
Audrey C
AC
Marx
Gerald R
GR
Colan
Steven D
SD
Benson
Carol B
CB
Lock
James E
JE
Perry
Stanton B
SB
D001024:Aortic Valve Stenosis / Q000000981:diagnostic imaging / Q000196:embryology / Q000628:therapy*; D002404:Catheterization; D005318:Fetal Heart / Q000000981:diagnostic imaging / Q000254:growth & development / Q000473:pathology; D046128:Fetal Therapies / Q000379:methods*; D005865:Gestational Age; D006801:Humans; D018636:Hypoplastic Left Heart Syndrome / Q000517:prevention & control*; D010865:Pilot Projects; D016896:Treatment Outcome; D016216:Ultrasonography, Prenatal; D018487:Ventricular Dysfunction, Left / Q000196:embryology