Abstract 17268: Resolution of Aortic Regurgitation following Fetal Balloon Aortic Valvuloplasty
Background. Fetal balloon aortic valvuloplasty (FAV) can improve left heart growth and function, preventing evolution to HLHS in some patients. Aortic regurgitation (AR) is frequently observed by color Doppler after technically successful FAV. In contrast to neonatal valvuloplasty, fetal AR has been observed to improve and even resolve by birth. Our aim is to analyze anatomic and technical factors that might result in AR post FAV and characterize the resolution of AR in the perinatal period.
Methods. Fetuses who underwent a technically successful FAV were reviewed and the following variables analyzed: aortic valve diameter; balloon to annulus ratio (BAR); and gestational age (GA) at FAV.
Results. Sixty-five fetuses had a technically successful FAV at a median GA of 23 (19-31) weeks. AR was observed immediately after the FAV in 40 fetuses (62%); trivial or mild in 19 and moderate or severe in 21 fetuses. The BAR was larger in fetuses that developed significant AR (1.20±0.13 versus 1.06±0.14; P=0.003). Two of 16 fetuses (13%) with a BAR ≤1 developed significant AR compared to 39% of fetuses with a BAR >1. Three of 21 fetuses with significant AR died after the procedure. The AR resolved completely in 9 of 18 survivors (50%), improved to trivial or mild in 7 (39%), and remained severe until birth in 2 (11%). Both patients with persistent severe AR died as newborns.
Conclusions. FAV carries a risk of AR. However, in most fetuses the AR improves by late gestation. A larger BAR (>1) is a risk factor for significant AR. The mechanism of AR resolution might be wound healing factors unique to the fetus. These include rapid cell division and the ability to repair and remodel tissue as demonstrated in animal studies. Moreover, unique hemodynamic factors such as reduced diastolic afterload due to the placenta and elevated LV end-diastolic pressure could mitigate the degree of AR, allowing for valve remodelling.
- © 2011 by American Heart Association, Inc.