Left Ventricular Strain, Arch Angulation, and Velocity-Time Integral Ratio Improve Performance of a Clinical Pathway for Fetal Diagnosis of Neonatal Coarctation of the Aorta.

INTRODUCTION: Neonatal presentation of coarctation of the aorta (CoA) is a potentially life-threatening condition that is difficult to diagnose in fetal life. We therefore sought to validate and compare novel metrics that may add diagnostic value for fetal CoA, including the diastolic to systolic aortic isthmus VTI ratio (VTId:VTIs), ascending aorta to descending aorta angle (AAo-DAo), transverse aorta to descending aorta angle (TAo-DAo), and LV longitudinal strain (LVS), then to evaluate whether these novel metrics improve specificity to identify fetuses at the highest risk for postnatal CoA without compromising sensitivity. METHODS: Retrospective cohort study of fetuses followed a prospective clinical pathway and previously classified as mild, moderate, or high-risk for CoA based on standard fetal echo metrics. Novel metrics were retrospectively measured in a blinded manner. RESULTS: Among fetuses with prenatal concern for CoA, VTId:VTIs, AAo-DAo angle, TAo-DAo angle, and LVS were significantly different between surgical and non-surgical cases (p < 0.01 for all variables). In the subgroup of moderate- and high-risk fetuses, the standard high-risk criteria (flow reversal at the foramen ovale or aortic arch) did not discriminate effectively between surgical and non-surgical cases. VTId:VTIs, AAo-Dao angle, Tao-DAo angle, and LVS all demonstrated greater discrimination than standard high-risk criteria, with specificity of 100% and PPV (positive predictive value) of 78-100%. CONCLUSIONS: The incorporation of novel metrics added diagnostic value to our clinical pathway for fetal CoA with higher specificity than the previous high-risk criteria. The incorporation of these metrics into the evaluation of fetuses at moderate- or high-risk for surgical CoA may improve prenatal counseling, allow for more consistent surgical planning, and ultimately optimize hospital resource allocation.

A Fetal Risk Stratification Pathway for Neonatal Aortic Coarctation Reduces Medical Exposure.

OBJECTIVE: To test the hypothesis that a fetal stratification pathway will effectively discriminate between infants at different levels of risk for surgical coarctation and reduce unnecessary medicalization. STUDY DESIGN: We performed a pre-post nonrandomized study in which we prospectively assigned fetuses with prenatal concern for coarctation to 1 of 3 risk categories and implemented a clinical pathway for postnatal management. Postnatal clinical outcomes were compared with those in a historical control group that were not triaged based on the pathway. RESULTS: The study cohort comprised 109 fetuses, including 57 treated along the fetal coarctation pathway and 52 historical controls. Among mild-risk fetuses, 3% underwent surgical coarctation repair (0% of those without additional heart defects), compared with 27% of moderate-risk and 63% of high-risk fetuses. The combined fetal aortic, mitral, and isthmus z-score best discriminated which infants underwent surgery (area under the curve = 0.78; 95% CI, 0.66-0.91). Compared with historical controls, infants triaged according to the fetal coarctation pathway had fewer delivery location changes (76% vs 55%; P = .025) and less umbilical venous catheter placement (74% vs 51%; P = .046). Trends toward shorter intensive care unit stay, hospital stay, and time to enteral feeding did not reach statistical significance. CONCLUSIONS: A stratified risk-assignment pathway effectively identifies a group of fetuses with a low rate of surgical coarctation and reduces unnecessary medicalization in infants who do not undergo aortic surgery. Incorporation of novel measurements or imaging techniques may improve the specificity of high-risk criteria.

Fetal Echocardiographic Parameters and Surgical Outcomes in Congenital Left-Sided Cardiac Lesions.

This study aimed to evaluate fetal echocardiographic parameters associated with neonatal intervention and single-ventricle palliation (SVP) in fetuses with suspected left-sided cardiac lesions. Initial fetal echocardiograms (1/2002-1/2017) were interpreted by the contemporary fetal cardiologist as coarctation of the aorta (COA), left heart hypoplasia (LHH), hypoplastic left heart syndrome (HLHS), mitral valve hypoplasia (MVH) ± stenosis, and aortic valve hypoplasia ± stenosis (AS). The cohort comprised 68 fetuses with suspected left-sided cardiac lesions (COA n = 15, LHH n = 9, HLHS n = 39, MVH n = 1, and AS n = 4). Smaller left ventricular (LV) length Z score, aortic valve Z score, ascending aorta Z score, and aorta/pulmonary artery ratio; left-to-right shunting at the foramen ovale; and retrograde flow in the aortic arch were associated with the need for neonatal intervention (p = 0.005-0.04). Smaller mitral valve (MV) Z score, LV length Z score, aortic valve Z score, ascending aorta Z score, aorta/pulmonary artery ratio, and LV ejection fraction, as well as higher tricuspid valve-to-MV (TV/MV) ratio, right ventricular-to-LV (RV/LV) length ratio, left-to-right shunting at the foramen ovale, abnormal pulmonary vein Doppler, absence of prograde aortic flow, and retrograde flow in the aortic arch were associated with SVP (p < 0.001-0.008). The strongest independent variable associated with SVP was RV/LV length ratio (stepwise logistical regression, p = 0.03); an RV/LV length ratio > 1.28 was associated with SVP with a sensitivity of 76% and specificity of 96% (AUC 0.90, p < 0.001). A fetal RV/LV length ratio of > 1.28 may be a useful threshold for identifying fetuses requiring SVP.

Impact of Fetal Somatic Growth on Pulmonary Valve Annulus Z-Scores During Gestation and Through Birth in Patients with Tetralogy of Fallot.

Previous studies have suggested reduced pulmonary valve annulus (PVA) growth and progression of pulmonary outflow obstruction in fetuses with tetralogy of Fallot (TOF). The goals of this study were to (1) investigate the trajectory of PVA growth in utero, and (2) compare two methods of z-score determination for fetal and postnatal PVA size by echocardiography in order to improve prenatal counseling for patients with TOF. Fetal echocardiograms (FE) at a single institution with a diagnosis of TOF between 8/2008 and 12/2015 were retrospectively reviewed. Patients included had at least 2 FEs and 1 immediate postnatal echocardiogram (TTE). Fetal and postnatal demographic, clinical, and echocardiographic data were collected. Fetal body surface area (BSA) was calculated by estimating fetal weight and height; z-scores were determined based on fetal gestational age (GA) and BSA for both FEs and TTEs. Fetal PVA z-scores by GA or BSA were then compared to postnatal PVA z-scores by BSA. Twenty-two patients with 44 FEs and 22 TTEs were included. GA at the first FE was 23 weeks ± 3.4 and 32 weeks ± 3.1 at the second FE. There was no difference in PVA z-scores (by BSA) between the first and second FE (p = 0.34), but a decrease in PVA z-scores (by BSA) between the second FE and TTE (- 1.6 ± 0.5 vs. - 2.0 ± 0.7; p = 0.01). Repeat comparison with fetal PVA z-scores indexed to GA revealed no difference in z-scores between the first and second FE, but an increase in PVA z-scores between the second FE (by GA) and TTE (by BSA) (- 4.1 ± 1.0 vs. - 2.0 ± 0.7; p < 0.0001). The rate of PVA growth between the two FEs (23 µm/day ± 9.8) and between the second FE and TTE (28 µm/day ± 42) remained comparable (p = 0.57); however, the rate of BSA increase was greater in later gestation (9 cm2/day ± 3 vs. 20 cm2/day ± 11; p = 0.001). In patients with TOF, the rate of PVA growth appears to remain consistent through gestation; however, somatic growth rate increases in late gestation. Fetal PVA z-scores indexed to GA are thus inaccurate in predicting postnatal PVA z-scores typically indexed to BSA. This observation should be considered during prenatal consultation and delivery planning.

Chronic antepartum maternal hyperoxygenation in a case of severe fetal Ebstein's anomaly with circular shunt physiology.

Perinatal mortality remains high among fetuses diagnosed with Ebstein's anomaly of the tricuspid valve. The subgroup of patients with pulmonary valve regurgitation is at particularly high risk. In the setting of pulmonary valve regurgitation, early constriction of the ductus arteriosus may be a novel perinatal management strategy to reduce systemic steal resulting from circular shunt physiology. We report the use of chronic antepartum maternal oxygen therapy for constriction of the fetal ductus arteriosus and modulation of fetal pulmonary vascular resistance in a late presentation of Ebstein's anomaly with severe tricuspid valve regurgitation, reversal of flow in the ductus arteriosus, and continuous pulmonary valve regurgitation.