Abstract 20454: Left and Right Ventricular Myocardial Vector Velocity Imaging In Fetuses Undergoing Prenatal Intervention for Aortic Stenosis
In fetuses with severe aortic stenosis (AS), in utero balloon dilation of the aortic valve (IUBD) has been shown to prevent progression to hypoplastic left heart syndrome in some patients. Anatomic and circulatory factors associated with postnatal outcome after IUBD have been assessed, but our understanding of the ventricular functional impact of this therapy has not been defined. We used vector velocity imaging (VVI) to evaluate changes in RV and LV strains on fetal echo before and late after IUBD for AS. We studied 36 fetuses that had adequate images pre- and post-IUBD. In a retrospective and blinded fashion, we used VVI to analyze RV and LV myocardial longitudinal strain (LS, 4-chamber view) and LV circumferential strain (CS, short-axis view). We analyzed data acquired 1 day pre-IUBD (gestational age 24±3 wks) and at the last prenatal follow-up echo (34±3 wks), and compared ventricular strains between the 2 studies. We also assessed the relationship between strain and postnatal outcome. Pre-IUBD, global LS of RV and LV and LV CS were −9.5±3.2, −2.5±1.4, and −2.3±2.4%, respectively, whereas in control fetuses they were −16.0±3.2, −15.2±2.6 and −18.7±3.3%. All LV and RV strain parameters (except basal RV lateral wall) were higher than normal (p≤0.001). At follow-up fetal echo after IUBD, fetuses that went on to have a biventricular circulation postnatally (n=13) had decreases in LV LS in the basal (−3.2±2.7 to −8.4±6.4% p=0.008) and mid-lateral wall segments (−3.1±2.6 to −10.3±9.7% p=0.01), in the mid septum (−1.9±1.6 to −4.1±3.5% p=0.05), and in CS in all segments except posterior and posterolateral (global CS improved from −2.5±3.5 to −7.0±4.7%; p=0.01). In contrast, fetuses that went on to have a univentricular circulation (n=17) did not have decreases in strain in any LV segment. The univentricular repair group had decreased mid-RV septal LS (−3.1±2.6 to −7.0 ±5.3%, p=0.001), but no other RV strain parameters changed in either group. VVI evaluation of LV and RV strain, not previously used in this unique population, shows that IUBD for fetal AS can Results in improved LV LS and CS. These changes may be an early indication of patients likely to achieve a biventricular outcome after birth. Further study is warranted in this unique population.
- © 2010 by American Heart Association, Inc.