Predicting High-Risk Fetal Cardiac Disease Anticipated to Need Immediate Postnatal Stabilization and Intervention with Planned Pediatric Cardiac Operating Room Delivery.

BACKGROUND: Distances between delivery and cardiac services can make the care of fetuses with cardiac disease at risk of acute cardiorespiratory instability at birth a challenge. In 2013 we implemented a fetal echocardiography-based algorithm targeting fetuses considered high risk for acute cardiorespiratory instability at ≤2 hours of birth for delivery in our pediatric cardiac operating room of our children's hospital, and, herein, examine our experience. METHODS AND RESULTS: We reviewed maternal and postnatal medical records of all fetuses with cardiac disease encountered January 2013 to March 2022 considered high risk for acute cardiorespiratory instability. Secondary analysis was performed including all fetuses with diagnoses of d-transposition of the great arteries/intact ventricular septum (d-TGA/IVS) and hypoplastic left heart syndrome (HLHS) encountered over the study period. Forty fetuses were considered high risk for acute cardiorespiratory instability: 15 with d-TGA/IVS and 7 with HLHS with restrictive atrial septum, 4 with absent pulmonary valve syndrome, 3 with obstructed anomalous pulmonary veins, 2 with severe Ebstein anomaly, 2 with thoracic/intracardiac tumors, and 7 others. Pediatric cardiac operating room delivery occurred for 33 but not for 7 (5 with d-TGA/IVS, 2 with HLHS with restrictive atrial septum). For high-risk cases, fetal echocardiography had a positive predictive value of 50% for intervention/extracorporeal membrane oxygenation/death at ≤2 hours and 70% at ≤24 hours. Of "low-risk" cases, 6/46 with d-TGA/IVS and 0/45 with HLHS required intervention at ≤2 hours. Fetal echocardiography for predicting intervention/extracorporeal membrane oxygenation/death at ≤2 hours had a sensitivity of 67%, specificity 93%, and positive and negative predictive values of 80% and 87%, respectively, for d-TGA/IVS, and 100%, 95%, 71%, and 100% for HLHS, respectively. CONCLUSIONS: Fetal echocardiography can predict the need for urgent intervention in a majority with d-TGA/IVS and HLHS and in half of the entire spectrum of high-risk cardiac disease.

Impact of Neonatal Intervention on Left Ventricular Performance in Ebstein's Anomaly and Tricuspid Valve Dysplasia.

BACKGROUND: Severe neonatal Ebstein's anomaly (EA) and tricuspid valve dysplasia (TVD) are associated with high perinatal morbidity and mortality. The authors recently demonstrated left ventricular (LV) dysfunction and dyssynchrony to be prevalent in affected newborns and to contribute to poor outcomes. The aim of this study was to investigate the impact of patent ductus arteriosus (PDA) closure, spontaneous or surgical ligation, or right ventricular exclusion (Starnes procedure) on LV performance in neonatal EA and TVD. METHODS: Neonates with EA or TVD encountered from 2004 to 2018 at three institutions were identified. Pre- and postoperative LV function was assessed using two-dimensional, Doppler-derived deformation (six-segment vector velocity imaging) and two measures of mechanical dyssynchrony (the SD of time to peak and global dyssynchrony index), and values were compared using paired t test analysis or the Wilcoxon rank sum test. RESULTS: Before the intervention, LV function was impaired in the PDA (n = 18) and Starnes (n = 6) groups and was similar between groups. After PDA closure, LV performance did not change. After the Starnes procedure, however, LV function, including synchrony, improved significantly: fractional area change from 45 ± 5% to 58 ± 8% (P = .003), global circumferential strain from -18.2 ± 5.0% to -32.5 ± 5.5% (P = .01), cardiac index from 1.9 ± 0.3 to 3.9 ± 1.5 L/min/m2 (P = .05), and circumferential strain dyssynchrony (dyssynchrony index from 0.19 ± 0.09 to 0.04 ± 0.02 [P = .009] and SD of time to peak from 59.8 ± 18.5 to 29.9 ± 8.2 [P = .02]). CONCLUSION: The Starnes procedure results in early improvements in LV dysfunction and dyssynchrony, not observed after PDA closure in neonatal severe EA and TVD, which may benefit critically unwell neonates.

Perinatal iron restriction is associated with changes in neonatal cardiac function and structure in a sex-dependent manner.

Iron deficiency (ID) is common during gestation and in early infancy and can alter developmental trajectories with lasting consequences on cardiovascular health. While the effects of ID and anemia on the mature heart are well documented, comparatively little is known about their effects and mechanisms on offspring cardiac development and function in the neonatal period. Female Sprague-Dawley rats were fed an iron-restricted or iron-replete diet before and during pregnancy. Cardiac function was assessed in a cohort of offspring on postnatal days (PD) 4, 14, and 28 by echocardiography; a separate cohort was euthanized for tissue collection and hearts underwent quantitative shotgun proteomic analysis. ID reduced body weight and increased relative heart weights at all time points assessed, despite recovering from anemia by PD28. Echocardiographic studies revealed unique functional impairments in ID male and female offspring, characterized by greater systolic dysfunction in the former and greater diastolic dysfunction in the latter. Proteomic analysis revealed down-regulation of structural components by ID, as well as enriched cellular responses to stress; in general, these effects were more pronounced in males. ID causes functional changes in the neonatal heart, which may reflect an inadequate or maladaptive compensation to anemia. This identifies systolic and diastolic dysfunction as comorbidities to perinatal ID anemia which may have important implications for both the short- and long-term cardiac health of newborn babies. Furthermore, therapies which improve cardiac output may mitigate the effects of ID on organ development.

Left Ventricular Dysfunction in Neonatal Ebstein's Anomaly and Tricuspid Valve Dysplasia.

BACKGROUND: The mechanisms and prognostic importance of left ventricular (LV) dysfunction in neonatal Ebstein's anomaly (EA) and tricuspid valve dysplasia (TVD) are not well understood. The authors recently demonstrated reduced cardiac output and dyssynchrony to be common in fetal EA/TVD and therefore hypothesized that LV dysfunction may be associated with worse outcomes in neonatal EA/TVD. METHODS: A multicenter retrospective case-control study was conducted among neonatal patients with EA/TVD (n = 32) and a healthy control cohort (n = 17) encountered from 2004 to 2019. The left ventricle was assessed in the first 48 hours after birth using two-dimensional, Doppler-derived, six-segment global and segmental longitudinal strain and circumferential strain (CS) and dyssynchrony indices (the SD of time-to-peak strain and a novel global dyssynchrony index [DI], calculated as [peak segmental average - peak global average]/peak segmental average). RESULTS: Neonates with EA/TVD demonstrated reduced combined cardiac index (4.2 ± 1.5 L/min/m2 vs 6.5 ± 2.2 L/min/m2 in control subjects, P < .001), impaired LV CS (-15.4 ± 6.9 vs -26.2 ± 5.8, P < .001), and increased circumferential dyssynchrony (CS DI 0.20 ± 0.16 vs 0.09 ± 0.04 [P = .019]; SD of time-to-peak CS 63 ± 25 vs 40 ± 15 [P = .003]). Transplantation-free survival occurred in 20 of 32 patients (63%) at 6 months. Increased CS DI and absence of pulmonary valve flow (PVF) were most predictive of mortality; CS DI > 0.2 was associated with 25% survival in subjects without PVF, whereas all patients with CS DI < 0.1 survived. CONCLUSIONS: In neonates with EA/TVD and absence of PVF, there is abnormal LV deformation and compromised cardiac output in association with increased dyssynchrony. Increased CS DI is associated with increased risk for mortality in EA/TVD with no forward PVF.

Influence of extreme prematurity and bronchopulmonary dysplasia on cardiac function.

OBJECTIVE: Prematurity and bronchopulmonary dysplasia (BPD) are associated with poorly understood abnormalities of ventricular function. We therefore comprehensively compared biventricular function in infants with and without BPD. METHODS: Prospective observational study in extremely preterm infants with (n = 20) and without (n = 38) BPD using conventional and advanced echocardiography at 28 days (T1) and near-term (T2). RESULTS: Infants with BPD had lower birth gestational age (26.7±1.9 vs 27.4±1.1 weeks, p = 0.047) and weight (884±207 vs 1108±190 g, p = 0.0001). BPD was associated with larger right ventricles (RV) and reduced RV systolic strain rate at T1 and pulmonary hypertensive indicators at T2 (pulmonary artery acceleration time BPD 51±17 vs no BPD 63±12 ms, p = 0.017). At T1/T2, infants with BPD had lower RV tissue Doppler velocities (e', a' and s) and higher E/e' ratios (T1: BPD 10.4±2.4 vs no BPD 6.2±3.1 cm/sec, p = 0.001; T2: BPD 8.0±3.1 vs no BPD 5.6±2.6 cm/sec, p = 0.02), altered LV diastolic function (apical circumferential T1 early diastolic strain rate BPD 2.8±0.8 vs no BPD 3.6±1.0 /sec, p = 0.04; T2 late diastolic strain rate, BPD 2.29 ± 0.99 vs no BPD 1.67±0.84 /sec, p = 0.03) and LV rotational mechanics (T1: twist rate BPD 90±16 vs no BPD 130±48 deg/sec, p = 0.008; untwist rate (UTR) BPD -69±90 vs no BPD -147±68 deg/sec, p = 0.008; torsion BPD 2.78±0.56 vs no BPD 4.48±1.74 deg/cm, p = 0.009; and T2: UTR BPD -132±69 vs no BPD -179±57 deg/sec, p = 0.013). CONCLUSION: BPD is associated with altered RV diastolic function that persists near term, with elevated pulmonary vascular resistance, and with persistent alterations in LV apical strain rate and rotational mechanics.

Right Ventricular Remodeling in Hypoplastic Left Heart Syndrome is Minimally Impacted by Cardiopulmonary Bypass: A Comparison of Norwood vs. Hybrid.

Right ventricular (RV) remodeling in hypoplastic left heart syndrome (HLHS) begins prenatally and continues through staged palliations. However, it is unclear if the most marked observed remodeling post-Norwood is secondary to cardiopulmonary bypass (CPB) exposure or if it is an adaptation intrinsic to the systemic RV. This study aims to determine the impact of CPB on RV remodeling in HLHS. Echocardiograms of HLHS survivors undergoing stage 1 Norwood (n = 26) or Hybrid (n = 20) were analyzed at pre- and post-stage 1, pre- and post-bidirectional cavo-pulmonary anastomosis (BCPA), and pre-Fontan. RV fractional area change (FAC), vector velocity imaging for longitudinal & derived circumferential deformation (global radial shortening (GRS) = peak radial displacement/end-diastolic diameter), and deformation ratio (longitudinal/ circumferential) were assessed. Both groups had similar age, clinical status and functional parameters pre-stage 1. No difference in RV size and sphericity at any stage between groups. RVFAC was normal (> 35%) throughout for both groups. Both Norwood and Hybrid patients had increased GRS (p = 0.0001) post-stage 1 and corresponding unchanged longitudinal strain, resulting in decreased deformation ratio (greater relative RV circumferential contraction), p = 0.0001. Deformation ratio remained decreased in both groups in subsequent stages. Irrespective of timing of the first CPB exposure, both Norwood and Hybrid patients underwent similar RV remodeling, with relative increase in circumferential to longitudinal contraction soon after stage 1 palliation. The observed RV remodeling in HLHS survivors were minimally impacted by CPB.

Quantitative Assessment of Left Ventricular Dysfunction in Fetal Ebstein's Anomaly and Tricuspid Valve Dysplasia.

BACKGROUND: Fetal Ebstein's anomaly and tricuspid valve dysplasia (EA/TVD) are associated with high perinatal mortality relative to pulmonary atresia with intact ventricular septum (PAIVS), despite both requiring redistribution of the cardiac output (CO) to the left ventricle (LV). LV dysfunction is suspected to contribute to adverse outcomes in EA/TVD. OBJECTIVE: We sought to examine global and segmental LV function in fetal EA/TVD with comparison to normal controls and PAIVS. We hypothesized that LV dysfunction in EA/TVD is associated with abnormal LV remodeling and interventricular mechanics. METHODS: We retrospectively identified 63 cases of fetal EA/TVD (40 with retrograde ductal flow) and 22 cases of PAIVS encountered from 2004 to 2015 and compared findings to 77 controls of comparable gestational age. We measured the combined CO and global LV function using two-dimensional, Doppler-derived, deformational (six-segmental vector velocity imaging) and dyssynchrony indices (DIs; SD of time to peak), and a novel global DI. RESULTS: EA/TVD fetuses demonstrated abnormal LV global systolic function with reduced ejection fraction, fractional area change, and CO, while in PAIVS we observed a normal ejection fraction, fractional area change, and CO. PAIVS, but not EA/TVD, demonstrated increased LV sphericity, suggestive of remodeling, and associated enhanced radial function in the third trimester. In contrast, while EA/TVD fetuses had normal LV segmental longitudinal strain, there was abnormal radial segmental deformation and LV dyssynchrony with increased SD of time to peak and DI. CONCLUSIONS: Fetal EA/TVD is associated with a lack of spherical remodeling and presence of mechanical dyssynchrony, which likely contribute to reduced CO and ejection fraction. Clinical monitoring of LV function is warranted in fetal EA/TVD. Further studies incorporating quantification of LV function into prediction models for adverse outcomes are required.

Hypoplastic Left Heart Syndrome Is Not a Predictor of Worse Intermediate Mortality Post Fontan.

BACKGROUND: An increasing proportion of those living with single ventricle physiology have hypoplastic left heart syndrome (HLHS). Our objective was to assess the association between HLHS and outcomes post Fontan operation. METHODS: All pediatric patients who underwent a Fontan procedure at the University of Alberta between 1996 and 2016 were included. Follow-up clinical data collected included early and late surgical or catheter reintervention, echocardiography, and long-term transplant-free survival. Characteristics were compared between those with and without HLHS, and the association between outcomes and HLHS were assessed. RESULTS: A total of 320 children (median age 3.3 years, interquartile range 2.8 to 3.9 years; 121 [43.4%] female) underwent a Fontan procedure over the course of the study. Nearly one third of subjects had HLHS (107, 33.4%). Patients with HLHS were more likely to have abnormal ventricular function (19.6% versus 7.0%, p = 0.003) and worse than mild atrioventricular valve (AVV) regurgitation (23.4 versus 9.2%, p = 0.001) preoperatively. HLHS was not predictive of in-hospital Fontan failure (odds ratio 0.82, 95% CI 0.28, 2.39), late reintervention (hazard ratio [HR] 1.08, 95% CI 0.66, 1.76), or transplant-free survival (HR 1.58, 95% CI 0.72, 3.44). Subjects with HLHS were more likely to have more than mild AVV regurgitation (31.6% versus 13.3%, p = 0.028) and abnormal ventricular function (29.8% versus 10.7%, p < 0.0001) at late follow-up. CONCLUSIONS: Patients with HLHS who survive to the Fontan procedure do no worse with the operation than those with other anatomy. Given worse late ventricular function and AVV regurgitation, equivalent survival may not persist throughout a patient's life course.

Timing of diagnosis affects mortality in critical congenital heart disease.

OBJECTIVE: Screening for critical congenital heart disease (CHD) with prenatal ultrasound or postnatal pulse oximetry has the potential to improve outcome. To guide screening recommendations, this study aimed to identify the proportion and outcome of major CHD diagnosed before (early) or after (late) postnatal discharge prior to the introduction of postnatal oximetry screening. DESIGN: A retrospective, population-based review of all major CHD in New Zealand from 2006 to 2010. The timing of diagnosis relative to discharge and to intervention in critical and non-critical cases with intention to treat was determined, as was the relationship of diagnostic timing to mortality at 1 year of age. RESULTS: Late diagnosis occurred in 20% of critical and 51% of non-critical cases. Mortality occurred in 18% of critical vs 8% of non-critical cases. Mortality was lower with an early diagnosis of critical CHD (early diagnosis 16% vs late diagnosis 27%, p=0.04). Isolated critical CHD benefited most from early diagnosis (mortality, early diagnosis 12% vs late diagnosis 29%, p=0.002). Early diagnosis occurred in >90% critical complex CHD and hypoplastic left heart syndrome, 85% d-transposition of the great arteries (d-TGA) and 53% critical left ventricular outflow tract obstruction (LVOTO). Deaths in d-TGA and LVOTO primarily occurred prior to intervention and for d-TGA most often when birth was distant from the cardiac centre. CONCLUSIONS: Excess mortality occurs following late diagnosis of critical CHD, and for d-TGA even with early diagnosis if intervention is not immediately available. Antenatal detection retains an important role in reducing mortality related to critical CHD.

Two cases of warfarin-induced tracheobronchial calcification after Fontan surgery.

This study identified tracheobronchial cartilage calcification in children with congenital heart disease. Calcification of the tracheobronchial airways has been found previously in adults receiving warfarin and in children receiving warfarin after mitral valve replacement. A 9-year-old girl who had received a Fontan repair 6 years previously underwent a cardiac computed tomography (CT) scan to evaluate pulmonary artery size. The result was an incidental finding of extensive tracheobronchial cartilage calcification. A retrospective review of all pediatric Fontan patients who had undergone cardiac CT was conducted to search for calcification of the tracheobronchial cartilage. The study investigated ten pediatric Fontan patients who had undergone cardiac CT scanning. Two patients with extensive calcification of the tracheobronchial airways were identified. The index case had hypoplastic left heart syndrome, and the patient had undergone a staged repair with the Fontan at the age of 3 years. A 16-year-old boy with tricuspid atresia had undergone staged repair and Fontan at the age of 3.5 years. These two patients had received continuous warfarin therapy for 6 and 13 years, respectively. Other common causes of airway calcification were excluded from the study. This report describes warfarin-induced tracheobronchial calcification in patients after the Fontan procedure. This finding has possible implications for airway growth and vascular calcification.