Hemodynamic and Echocardiographic Predictors of Mortality in Pediatric Patients on Venoarterial Extracorporeal Membrane Oxygenation: A Multicenter Investigation.

BACKGROUND: Venoarterial extracorporeal membrane oxygenation (ECMO) supports patients with advanced cardiac dysfunction; however, mortality occurs in a significant subset of patients. The authors performed a multicenter, prospective study to determine hemodynamic and echocardiographic predictors of mortality in children placed on ECMO for cardiac support. METHODS: Over 8 years, six heart centers prospectively assessed echocardiographic and hemodynamic variables on full and minimum ECMO flow. Sixty-three patients were enrolled, ranging in age from 1 day to 16 years. Hemodynamic measurements included heart rate, vasoactive inotropic score, arteriovenous oxygen difference, pulse pressure, and lactate. Echocardiographic variables included shortening fraction, ejection fraction (EF), right ventricular fractional area change, outflow tract Doppler-derived stroke distance (velocity-time integral [VTI]), and degree of atrioventricular valve regurgitation. Patients were stratified into two groups: those who were able to wean within 48 hours of assessment and survived without ventricular assist devices or orthotopic heart transplantation (successful wean group) and those with unsuccessful weaning. For each patient, variables were compared between full and minimum ECMO flow for each group. RESULTS: Thirty-eight patients (60%) formed the unsuccessful group (two with ventricular assist devices, four with orthotopic heart transplantation, 24 deaths), and 25 constituted the successful wean group. At minimum flow, higher EF (53 ± 16% vs 40 ± 20%, P = .0094), less mitral regurgitation (0.8 ± 0.9 vs 1.4 ± 0.9, P = .0329), and lower central venous pressure (12.0 ± 3.9 vs 14.7 ± 5.4 mm Hg), along with higher VTI (9.0 ± 2.9 vs 6.8 ± 3.7 cm, P = .0154), correlated successful weaning. A longer duration of ECMO (8 vs 5 days, P < .0002) was associated with unsuccessful weaning. Multivariate logistic regression predicted minimum-flow EF and VTI to independently predict successful weaning with cutoff values by receiver operating characteristic analysis of EF > 41% (area under the curve, 0.712; P = .0005) and VTI > 7.9 cm (area under the curve, 0.729; P = .0010). CONCLUSIONS: Diminished VTI or EF during ECMO weaning predicts the need for orthotopic heart transplantation or ventricular assist device support or death in children on ECMO for cardiac dysfunction. Increased postwean central venous pressure or mitral regurgitation along with a prolonged ECMO course also predicted these adverse outcomes. These measurements should be used to help discriminate which patients will require alternative methods of circulatory support for survival.

Impact of Udenafil on Echocardiographic Indices of Single Ventricle Size and Function in FUEL Study Participants.

BACKGROUND: The FUEL trial (Fontan Udenafil Exercise Longitudinal) demonstrated statistical improvements in exercise capacity following 6 months of treatment with udenafil (87.5 mg po BID). The effect of udenafil on echocardiographic measures of single ventricle function in this cohort has not been studied. METHODS: The 400 enrolled participants were randomized 1:1 to udenafil or placebo. Protocol echocardiograms were obtained at baseline and 26 weeks after initiation of udenafil/placebo. Linear regression compared change from baseline indices of single ventricle systolic, diastolic and global function, atrioventricular valve regurgitation, and mean Fontan fenestration gradient in the udenafil cohort versus placebo, controlling for ventricular morphology (left ventricle versus right ventricle/other) and baseline value. RESULTS: The udenafil participants (n=191) had significantly improved between baseline and 26 weeks visits compared to placebo participants (n=195) in myocardial performance index (P=0.03, adjusted mean difference [SE] of changes between groups -0.03[0.01]), atrioventricular valve inflow peak E (P=0.009, 3.95 [1.50]), and A velocities (P=0.034, 3.46 [1.62]), and annular Doppler tissue imaging-derived peak e' velocity (P=0.008, 0.60[0.23]). There were no significant differences in change in single ventricle size, systolic function, atrioventricular valve regurgitation severity, or mean fenestration gradient. Participants with a dominant left ventricle had significantly more favorable baseline values of indices of single ventricle size and function (lower volumes and areas, E/e' ratio, systolic:diastolic time and atrioventricular valve regurgitation, and higher annular s' and e' velocity). CONCLUSIONS: FUEL participants who received udenafil demonstrated a statistically significant improvement in some global and diastolic echo indices. Although small, the changes in diastolic function suggest improvement in pulmonary venous return and/or augmented ventricular compliance, which may help explain improved exercise performance in that cohort. REGISTRATION: URL: https://clinicaltrials.gov; Unique Identifier: NCT02741115.

Predictors and clinical significance of pericardial effusions after pediatric heart transplantation.

BACKGROUND: We aimed to describe the incidence, risk factors, and clinical outcomes of pericardial effusions within 6 months after pediatric heart transplantation (HT). METHODS: A single-center retrospective cohort study was performed on all pediatric HT recipients from 2004 to 2018. Logistic regression was used to identify factors associated with pericardial effusions post-HT, and survival was compared using log-rank test. RESULTS: During the study period, 97 HTs were performed in 93 patients. Fifty patients (52%) had a ≥small pericardial effusion within 6 months, 16 of which were, or became, ≥moderate in size. Pericardial drain was placed in 8 patients. In univariate analysis, larger recipient body surface area (p = .01) and non-congenital heart disease (p = .002) were associated with pericardial effusion development. Donor/recipient size ratios, post-HT hemodynamics, and rejection did not correlate with pericardial effusion development. In multivariable analysis, non-congenital heart disease (adjusted odds ratio 3.3, p = .01) remained independently associated with development of pericardial effusion. There were no significant differences in post-HT survival between patients with and without ≥small (p = .68) or ≥moderate pericardial effusions (p = .40). CONCLUSIONS: Pericardial effusions are common after pediatric HT. Patients with cardiomyopathy, or non-congenital heart disease, were at higher risk for post-HT pericardial effusions. Pericardial effusions increased morbidity but had no effect on mortality in our cohort. The risk factors identified may be used for anticipatory guidance in pediatric HT.

Pediatric Heart Network Echocardiographic Z Scores: Comparison with Other Published Models.

BACKGROUND: Different methods have resulted in variable Z scores for echocardiographic measurements. Using the measurements from 3,215 healthy North American children in the Pediatric Heart Network (PHN) echocardiographic Z score database, the authors compared the PHN model with previously published Z score models. METHODS: Z scores were derived for cardiovascular measurements using four models (PHN, Boston, Italy, and Detroit). Model comparisons were performed by evaluating (1) overlaid graphs of measurement versus body surface area with curves at Z = -2, 0, and +2; (2) scatterplots of PHN versus other Z scores with correlation coefficients; (3) Bland-Altman plots of PHN versus other Z scores; and (4) comparison of median Z scores for each model. RESULTS: For most measurements, PHN Z score curves were similar to Boston and Italian curves but diverged from Detroit curves at high body surface areas. Correlation coefficients were high when comparing the PHN model with the others, highest with Boston (mean, 0.99) and lowest with Detroit (mean, 0.90). Scatterplots suggested systematic differences despite high correlations. Bland-Altman plots also revealed poor agreement at both extremes of size and a systematic bias for most when comparing PHN against Italian and Detroit Z scores. There were statistically significant differences when comparing median Z scores between the PHN and other models. CONCLUSIONS: Z scores from the multicenter PHN model correlated well with previous single-center models, especially the Boston model, which also had a large sample size and similar methodology. The Detroit Z scores diverged from the PHN Z scores at high body surface area, possibly because there were more subjects in this category in the PHN database. Despite excellent correlation, significant differences in Z scores between the PHN model and others were seen for many measurements. This is important when comparing publications using different models and for clinical care, particularly when Z score thresholds are used to guide diagnosis and management.

Third trimester predictors of interventional timing and accuracy of fetal anticipatory guidance in tetralogy of Fallot: A multi-center study.

OBJECTIVE: The objective was to evaluate and improve accuracy of anticipatory counseling regarding neonatal intervention for prenatally diagnosed tetralogy of Fallot (TOF) by assessing new and previously published predictors of neonatal intervention. METHODS: This is a multi-center, retrospective study from three centers of 112 fetal TOF patients undergoing third trimester fetal echocardiograms from 2004 to 2017. Additional cardiac defects requiring neonatal intervention were excluded. Fetal echocardiographic, clinical, and consultation data were compared between neonatal and late intervention. Optimal echocardiographic values were determined. RESULTS: Twenty-six infants (23%) required neonatal intervention. Those infants had significantly different pulmonary valve (PV) z-scores, PV:aortic valve (AoV) ratios, PV:AoV z-score differences (absolute difference between z-scores), and increased likelihood of abnormal ductal flow. Counseling during fetal echocardiogram regarding interventional timing was accurate for 50% needing neonatal intervention and 86% undergoing late intervention (P = .002). The best neonatal intervention predictors were PV:AoV ratio of <0.6 and counseling for neonatal intervention. PV:AoV z-score difference ≥5 provided 89% negative predictive value for excluding patients from neonatal repair. CONCLUSIONS: Third trimester fetal echocardiograms can predict interventional timing. The best predictors of neonatal intervention are PV:AoV ratio <0.6, PV:AoV z-score difference ≥5, and cardiologist counseling that neonatal intervention was likely.

Biventricular Badness: Rare Images of Ebstein Anomaly of the Tricuspid Valve in a Patient with Hypoplastic Left Heart Syndrome.

We report a rare case of hypoplastic left heart syndrome coexisting in a patient with Ebstein anomaly of the tricuspid valve, which has previously been described only in pathological studies. A fetal echocardiogram at 27-weeks gestation showed severe aortic stenosis with evolving hypoplastic left heart syndrome, significant endocardial fibroelastosis, a dysplastic tricuspid valve with moderate regurgitation, right atrial and ventricular dilation, and signs of fetal congestive heart failure. Due to inadequate left heart size, the patient was not a candidate for fetal intervention for critical aortic stenosis, and repeat studies showed progression of the lesion through the pregnancy. The infant was delivered at 36-weeks gestation with signs of hydrops, and a postnatal echocardiogram confirmed hypoplastic left heart syndrome as well as severe Ebstein anomaly of the tricuspid valve. The infant did not survive to intervention.

Chromosomal Imbalances in Patients with Congenital Cardiac Defects: A Meta-analysis Reveals Novel Potential Critical Regions Involved in Heart Development.

OBJECTIVE: Congenital cardiac defects represent the most common group of birth defects, affecting an estimated six per 1000 births. Genetic characterization of patients and families with cardiac defects has identified a number of genes required for heart development. Yet, despite the rapid pace of these advances, mutations affecting known genes still account for only a small fraction of congenital heart defects suggesting that many more genes and developmental mechanisms remain to be identified. DESIGN: In this study, we reviewed 1694 described cases of patients with cardiac defects who were determined to have a significant chromosomal imbalance (a deletion or duplication). The cases were collected from publicly available databases (DECIPHER, ISCA, and CHDWiki) and from recent publications. An additional 68 nonredundant cases were included from the University of Michigan. Cases with multiple chromosomal or whole chromosome defects (trisomy 13, 18, 21) were excluded, and cases with overlapping deletions and/or insertions were grouped to identify regions potentially involved in heart development. RESULTS: Seventy-nine chromosomal regions were identified in which 5 or more patients had overlapping imbalances. Regions of overlap were used to determine minimal critical domains most likely to contain genes or regulatory elements involved in heart development. This approach was used to refine the critical regions responsible for cardiac defects associated with chromosomal imbalances involving 1q24.2, 2q31.1, 15q26.3, and 22q11.2. CONCLUSIONS: The pattern of chromosomal imbalances in patients with congenital cardiac defects suggests that many loci may be involved in normal heart development, some with very strong and direct effects and others with less direct effects. Chromosomal duplication/deletion mapping will provide an important roadmap for genome-wide sequencing and genetic mapping strategies to identify novel genes critical for heart development.

Functional analysis of candidate genes in 2q13 deletion syndrome implicates FBLN7 and TMEM87B deficiency in congenital heart defects and FBLN7 in craniofacial malformations.

Recurrent 2q13 deletion syndrome is associated with incompletely penetrant severe cardiac defects and craniofacial anomalies. We used an atypical, overlapping 1.34 Mb 2q13 deletion in a patient with pathogenically similar congenital heart defects (CHD) to narrow the putative critical region for CHD to 474 kb containing six genes. To determine which of these genes is responsible for severe cardiac and craniofacial defects noted in the patients with the deletions, we used zebrafish morpholino knockdown to test the function of each orthologue during zebrafish development. Morpholino-antisense-mediated depletion of fibulin-7B, a zebrafish orthologue of fibulin-7 (FBLN7), resulted in cardiac hypoplasia, deficient craniofacial cartilage deposition and impaired branchial arch development. TMEM87B depletion likewise resulted in cardiac hypoplasia but with preserved branchial arch development. Depletion of both fibulin-7B and TMEM87B resulted in more severe defects of cardiac development, suggesting that their concurrent loss may enhance the risk of a severe cardiac defect. We postulate that heterozygous loss of FBLN7 and TMEM87B account for some of the clinical features, including cardiac defects and craniofacial abnormalities associated with 2q13 deletion syndrome.

5/6 Area length method for left-ventricular ejection-fraction measurement in adults with repaired tetralogy of Fallot: comparison with cardiovascular magnetic resonance.

In patients with repaired tetralogy of Fallot (rTOF), left-ventricular ejection fraction (LVEF) predicts adverse outcomes. Two-dimensional echocardiographic (2DE) methods of measuring LVEF require geometric assumptions and may be limited in this population due to altered ventricular geometry. This study evaluated the performance of the 5/6 area × length (AL) method in this population as well as which factors limit agreement with the results of cardiovascular magnetic resonance (CMR). In 20 patients with rTOF (28.5 ± 14.7 years old) and CMR and 2DE within 3 months, two investigators blinded to CMR measured LVEF from 2DE by the AL method, biplane Simpson's (BiS) method, and visual estimate. Two investigators blinded to 2DE measured LVEF from CMR by Simpson's and AL methods. The AL method on 2DE more closely approximated LVEF by CMR (r = 0.73, p = 0.0003) than BiS method (r = 0.53, p = 0.02). AL method was not limited by geometric assumptions, as AL method on CMR closely approximated Simpson's method on CMR (r = 0.90, p < 0.0001) despite median left-ventricular diastolic eccentricity index of 1.24. AL method on 2DE was primarily limited by short-axis area measurement rather than foreshortening of the ventricle. In conclusion, in adults with rTOF, AL method on 2DE moderately approximates LVEF by CMR, even in the context of altered left-ventricular geometry. Although the AL method may be the most appropriate 2DE method in this population, significant limitations remain for LVEF assessment by 2DE, and strategies to optimize image position and border detection are essential.