Evaluation of left ventricular mass in children with left-sided congenital diaphragmatic hernia

Congenital Diaphragmatic Hernia Patients with Left Heart Hypoplasia and Left Ventricular Dysfunction Have Highest Odds of Mortality

OBJECTIVES

To describe the scope of left ventricular (LV) dysfunction and left heart hypoplasia (LHH) in infants with congenital diaphragmatic hernia (CDH), to determine associations with CDH severity, and to evaluate the odds of extracorporeal membrane oxygenation (ECMO) and death with categories of left heart disease.

STUDY DESIGN

Demographic and clinical variables were collected from a single-center, retrospective cohort of patients with CDH from January 2017 through May 2022. Quantitative measures of LV function and LHH were prospectively performed on initial echocardiograms. LHH was defined as ≥2 of the following: z score ≤ -2 of any left heart structure or LV end-diastolic volume <3 mL. LV dysfunction was defined as shortening fraction <28%, ejection fraction <60%, or global longitudinal strain <20%. The exposure was operationalized as a 4-group categorical variable (LV dysfunction +/-, LHH +/-). Logistic regression models evaluated associations with ECMO and death, adjusting for CDH severity.

RESULTS

One hundred eight-two patients (80.8% left CDH, 63.2% liver herniation, 23.6% ECMO, 12.1% mortality) were included. Twenty percent demonstrated normal LV function and no LHH (LV dysfunction-/LHH-), 37% normal LV function with LHH (LV dysfunction-/LHH+), 14% LV dysfunction without LHH (LV dysfunction+/LHH-), and 28% both LV dysfunction and LHH (LV dysfunction+/LHH+). There was a dose-response effect between increasing severity of left heart disease, ECMO use, and mortality. LV dysfunction+/LHH + infants had the highest odds of ECMO use and death, after adjustment for CDH severity [OR (95% CI); 1.76 (1.20, 2.62) for ECMO, 2.76 (1.63, 5.17) for death].

CONCLUSIONS

In our large single-center cohort, patients with CDH with LV dysfunction+/LHH + had the highest risk of ECMO use and death.

Inhaled Nitric Oxide Utilization in Congenital Diaphragmatic Hernia Treated With Extracorporeal Life Support: A Propensity Score Analysis

Although used commonly, ability of inhaled nitric oxide (iNO) to improve outcomes in infants with congenital diaphragmatic hernia (CDH) who receive extracorporeal life support (ECLS) remains controversial. We sought to determine the association between pre-ECLS use of iNO and mortality in infants with CDH from the Extracorporeal Life Support Organization (ELSO) Registry. Neonates who underwent ECLS for CDH were identified from the ELSO Registry from 2009 to 2019. Patients were categorized into those treated with iNO versus not prior to initiating ECLS. Patients were then matched 1:1 for case-mix based on pre-ECLS covariates using the propensity score (PS) for iNO treatment. The matched groups were compared for mortality. The matched cohorts were also compared for ELSO-defined systems-based complications as secondary outcomes. There were a total of 3,041 infants with an overall mortality of 52.2% and a pre-ECLS iNO use rate of 84.8%. With 1:1 matching, there were 461 infants with iNO use and 461 without iNO use. Following matching, use of iNO was not associated with a difference in mortality (odds ratio [OR] = 0.805; 95% confidence interval [CI], 0.621-1.042; p = 0.114). Results were similar in unadjusted analyses, and after controlling for covariates in the full cohort of patients and in the 1:1 matched data. Patients receiving iNO had significantly higher odds of renal complications (OR = 1.516; 95% CI, 1.141-2.014; p = 0.004), but no other significant differences were observed among secondary outcomes. ECLS use of iNO in CDH patients was not associated with a difference in mortality. Future randomized controlled studies are needed to delineate the utility of iNO in CDH patients.

The myocardial capillary network is altered in congenital diaphragmatic hernia in the fetal rabbit model

Congenital diaphragmatic hernia (CDH) is associated with thoracic compression of the lungs and heart caused by the herniated abdominal content, leading to cardiac modifications including pressure and vascular changes. Our aim was to investigate the experimental immunoexpression of the capillary proliferation, activation, and density of Ki-67, VEGFR2, and lectin in the myocardium after surgical creation of a diaphragmatic defect. Pregnant New Zealand rabbits were operated on the 25th gestational day in order to create left-sided CDH (LCDH, n=9), right-sided CDH (RCDH, n=9), and Control (n=9), for a total of 27 fetuses in 19 pregnant rabbits. Five days after the procedure, animals were sacrificed, and histology and immunohistochemistry studies of the harvested hearts were performed. Total body weight and heart weight were not significantly different among groups (P=0.702 and 0.165, respectively). VEGFR2 expression was increased in both ventricles in the RCDH group (P<0.0001), and Ki-67 immunoexpression was increased in the left ventricle in the LCDH group compared to Control and RCDH groups (P<0.0001). In contrast, capillary density was reduced in the left ventricle in the LCDH compared to the Control and RCDH groups (P=0.002). Left and right ventricles responded differently to CDH in this model depending on the laterality of the diaphragmatic defect. This surgical model of diaphragmatic hernia was associated with different expression patterns of capillary proliferation, activation, and density in the myocardium of the ventricles of newborn rabbits.

Diagnosis & management of pulmonary hypertension in congenital diaphragmatic hernia

Congenital diaphragmatic hernia (CDH) contributes to neonatal morbidity and mortality worldwide. Pulmonary hypertension (PH) is a key component of CDH pathophysiology and critical consideration for management and therapeutic options. PH associated with CDH has traditionally been attributed to pulmonary vascular maldevelopment and associated lung parenchymal hypoplasia, leading to pre-capillary increase in pulmonary vascular resistance (PVR). However, there is increasing recognition that left ventricular hypoplasia, dysfunction and elevated end diastolic pressure may contribute to post-capillary pulmonary hypertension in CDH patients. The interplay of these mechanisms and associated dysfunction in the right and left ventricles results in variable hemodynamic phenotypes in CDH. Clinical assessment of individual phenotype may help guide personalized management strategies, including effective use of pulmonary vasodilators and extra-corporeal membrane oxygenation. Ongoing investigation of the underlying mechanisms of PH in CDH, and efficacy of physiology-based treatment approaches may support improvement in outcomes in this challenging condition.

Congenital Diaphragmatic Hernia Repair in a Patient With Pallister-Killian Mosaic Syndrome and Left Ventricular Hypoplasia

We present the case of a two-week-old infant with congenital diaphragmatic hernia (CDH) and Pallister-Killian mosaic syndrome (PKS) for CDH repair. We discuss the pathophysiologic findings of both conditions and the resulting anesthetic challenges from their interplay.

Use of Prostaglandin E1 in the Management of Congenital Diaphragmatic Hernia-A Review

Congenital diaphragmatic hernia (CDH) is a rare congenital anomaly, whose presentation is complicated by pulmonary hypertension (PH), pulmonary hypoplasia, and myocardial dysfunction, each of which have significant impact on short-term clinical management and long-term outcomes. Despite many advances in therapy and surgical technique, optimal CDH management remains a topic of debate, due to the variable presentation, complex pathophysiology, and continued impact on morbidity and mortality. One of the more recent management strategies is the use of prostaglandin E1 (PGE1) infusion in the management of PH associated with CDH. PGE1 is widely used in the NICU in critical congenital cardiac disease to maintain ductal patency and facilitate pulmonary and systemic blood flow. In a related paradigm, PGE1 infusion has been used in situations of supra-systemic right ventricular pressures, including CDH, with the therapeutic intent to maintain ductal patency as a "pressure relief valve" to reduce the effective afterload on the right ventricle (RV), optimize cardiac function and support pulmonary and systemic blood flow. This paper reviews the current evidence for use of PGE1 in the CDH population and the opportunities for future investigations.

Expected small left heart size in the presence of congenital diaphragmatic hernia: Fetal values and Z-scores for infants confirmed to have no heart disease postnatally

OBJECTIVES

In fetuses with left-sided congenital diaphragmatic hernia (CDH), left heart structures may appear small, but usually normalize after birth in the absence of structural cardiac anomalies. To decrease the possibility of an erroneous diagnosis of structural heart disease, we identify normal values for left heart structures in the presence of left CDH and secondarily investigate the relationship of left heart size and survival to neonatal hospital discharge.

METHODS

Left heart structures [mitral valve (MV) and aortic valve (AoV) annulus diameter, left ventricle (LV) length and width] were measured by fetal echocardiogram in fetuses with left CDH and no congenital heart disease. We generated linear regression models to establish the relationship of gestational age for each left heart structure using data from fetuses who survived after birth. We calculated z-scores (normalized to gestational age), and assessed the relationship of survival to the size of each structure.

RESULTS

One hundred forty-two fetuses underwent fetal echocardiogram (median 25 weeks' gestation, IQR 23, 27 weeks). Left heart structures were deemed small when using published normative data from unaffected fetuses (z-scores: MV -1.09 ± 1.35, AoV -2.12 ± 1.16, LV length -1.36 ± 1.24, LV width -4.79 ± 0.79). CDH-specific models derived from log-transformed values yielded left-shifted distributions, reflecting the small structures (mean z-score lower by: MV 0.99 ± 0.30, AoV 2.04 ± 0.38, LV length 1.30 ± 0.36, and LV width 4.69 ± 0.28; p < 0.0001 for all comparisons). Non-survivors had worse z-scores than survivors for all measurements, but this did not reach statistical significance.

CONCLUSIONS

Log-transformed linear models generated new normative data for fetal left heart structures in left CDH, which may be used to allay antenatal concerns regarding structural left heart anomalies. There were no significant differences in z-scores between survivors and non-survivors, suggesting that in the absence of true structural disease, cardiac evaluation is not predictive in isolation and that causes of mortality are likely multifactorial in this population.

The heart in congenital diaphragmatic hernia: Knowns, unknowns, and future priorities

There is growing recognition that the heart is a key contributor to the pathophysiology of congenital diaphragmatic hernia (CDH), in conjunction with developmental abnormalities of the lung and pulmonary vasculature. Investigations to date have demonstrated altered fetal cardiac morphology, notably relative hypoplasia of the fetal left heart, as well as early postnatal right and left ventricular dysfunction which appears to be independently associated with adverse outcomes. However, many more unknowns remain, not least an understanding of the genetic and cellular basis for cardiac dysplasia and dysfunction in CDH, the relationship between fetal, postnatal and long-term cardiac function, and the impact on other parts of the body especially the developing brain. Consensus on how to measure and classify cardiac function and pulmonary hypertension in CDH is also required, potentially using both non-invasive imaging and biomarkers. This may allow routine assessment of the relative contribution of cardiac dysfunction to individual patient pathophysiological phenotype and enable better, individualized therapeutic strategies incorporating targeted use of fetal therapies, cardiac pharmacotherapies, and extra-corporeal membrane oxygenation (ECMO). Collaborative, multi-model approaches are now required to explore these unknowns and fully appreciate the role of the heart in CDH.

Lung Metabolomics Profiling of Congenital Diaphragmatic Hernia in Fetal Rats

Congenital diaphragmatic hernia (CDH) is characterized by the herniation of abdominal contents into the thoracic cavity during the fetal period. This competition for fetal thoracic space results in lung hypoplasia and vascular maldevelopment that can generate severe pulmonary hypertension (PH). The detailed mechanisms of CDH pathogenesis are yet to be understood. Acknowledgment of the lung metabolism during the in-utero CDH development can help to discern the CDH pathophysiology changes. Timed-pregnant dams received nitrofen or vehicle (olive oil) on E9.5 day of gestation. All fetal lungs exposed to nitrofen or vehicle control were harvested at day E21.5 by C-section and processed for metabolomics analysis using nuclear magnetic resonance (NMR) spectroscopy. The three groups analyzed were nitrofen-CDH (NCDH), nitrofen-control (NC), and vehicle control (VC). A total of 64 metabolites were quantified and subjected to statistical analysis. The multivariate analysis identified forty-four metabolites that were statistically different between the three groups. The highest Variable importance in projection (VIP) score (>2) metabolites were lactate, glutamate, and adenosine 5'-triphosphate (ATP). Fetal CDH lungs have changes related to oxidative stress, nucleotide synthesis, amino acid metabolism, glycerophospholipid metabolism, and glucose metabolism. This work provides new insights into the molecular mechanisms behind the CDH pathophysiology and can explore potential novel treatment targets for CDH patients.

Fetal cerebrovascular impedance is reduced in left congenital diaphragmatic hernia

OBJECTIVES

Congenital diaphragmatic hernia (CDH) can cause a significant mass effect in the fetal thorax, displacing the heart into the opposite hemithorax. In left-sided CDH (L-CDH), this is associated with smaller left-sided cardiac structures and reduced left-ventricular cardiac output (LVCO). The effect of these physiologic changes on cerebral blood flow is not well understood. We sought to describe the middle cerebral artery (MCA) pulsatility index (PI), a measure of cerebrovascular impedance, in fetuses with L-CDH and those with right-sided CDH (R-CDH) compared with unaffected fetuses, and the relationship between MCA-PI and LVCO. We hypothesized that MCA-PI would be lower in fetuses with L-CDH and similar in those with R-CDH compared to controls, and that MCA-PI would be correlated with LVCO.

METHODS

We identified all fetuses with CDH evaluated at The University of California San Francisco, San Francisco, CA, USA from 2011 to 2018. Fetal echocardiograms and ultrasound scans were reviewed. Umbilical artery and MCA Doppler examinations were assessed to calculate pulsatility indices. Ventricular outputs were calculated using Doppler-derived stroke volume and fetal heart rate. Lung-to-head ratio (LHR), estimated fetal weight, biparietal diameter (BPD) and head circumference (HC) were obtained from fetal sonograms. Measurements in fetuses with CDH, according to the side of the defect, were compared with those in unaffected, gestational age-matched controls. A subset of CDH survivors had available data on neurodevelopmental outcome, as assessed using the Bayley Scales of Infant Development, 3^rd edition.

RESULTS

A total of 64 fetuses with CDH (L-CDH, n = 53; R-CDH, n = 11) comprised the study groups, with 27 unaffected fetuses serving as controls. Mean gestational age at evaluation was similar between the three groups. Compared to controls, fetuses with L-CDH had significantly lower LVCO expressed as a percentage of combined cardiac output (CCO) (32%; 95% CI, 29-35% vs 38%; 95% CI, 33-42%; P = 0.04) and lower MCA-PI Z-score (-1.3; 95% CI, -1.7 to -1.0 vs 0.08; 95% CI, -0.5 to 0.6; P < 0.001), while they did not differ between the R-CDH group and controls. There was a strong positive association between LVCO as a percentage of CCO and MCA-PI Z-score in the overall cohort of CDH and control fetuses (P = 0.01). BPD and HC were similar between the three groups. At neurodevelopmental follow-up, mean cognitive, motor and language scores in the CDH group were within 1 SD of those in the general population.

CONCLUSION

MCA-PI values are significantly lower in fetuses with L-CDH as compared to controls, and lower LVCO was correlated with lower MCA vascular impedance. The neurodevelopmental effect of changes in MCA-PI in response to decreased LVCO is unknown, although, on average, CDH survivors had neurodevelopmental scores in the normal range. This may reflect a fetal compensatory mechanism in response to diminished antegrade cerebral blood flow. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

Update on Congenital Diaphragmatic Hernia

Congenital diaphragmatic hernia (CDH) is a rare developmental defect of the diaphragm, characterized by herniation of abdominal contents into the chest that results in varying degrees of pulmonary hypoplasia and pulmonary hypertension (PH). Significant advances in the prenatal diagnosis and identification of prognostic factors have resulted in the continued refinement of the approach to fetal therapies for CDH. Postnatally, protocolized approaches to lung-protective ventilation, nutrition, prevention of infection, and early aggressive management of PH have led to improved outcomes in infants with CDH. Advances in our understanding of the associated left ventricular (LV) hypoplasia and myocardial dysfunction in infants with severe CDH have allowed for the optimization of hemodynamics and management of PH. This article provides a comprehensive review of CDH for the anesthesiologist, focusing on the complex pathophysiology, advances in prenatal diagnosis, fetal interventions, and optimal postnatal management of CDH.

Early postnatal changes of circulating N-terminal-pro-B-type natriuretic peptide in neonates with congenital diaphragmatic hernia

BACKGROUND

Severity of lung hypoplasia, pulmonary hypertension (PH) and cardiac dysfunction are major contributors to mortality in congenital diaphragmatic hernia (CDH). Therefore, early assessment and management is important to improve outcome. NT-proBNP is an established cardiac biomarker with only limited data for early postnatal risk assessment in CDH newborns.

AIMS

To investigate the correlation of NT-proBNP at birth, 6 h, 12 h, 24 h, and 48 h with PH and cardiac dysfunction and the prognostic information of NT-proBNP for the use of ECMO support or mortality.

SUBJECTS

44 CDH newborns treated at our institution (December 2014-October 2017) were prospectively enrolled.

OUTCOME MEASURES

Primary clinical endpoint was either need for ECMO or death within the first 48 h (group A). Infants not receiving ECMO support were allocated to group B. Mortality was tested as secondary endpoint.

RESULTS

NT-proBNP levels measured at 6 h, 12 h, 24 h and 48 h postpartum correlated significantly with PH severity following NICU admission and at 24 h, and with severity of cardiac dysfunction at birth, 24 h, 48 h and after 7 days of life. There was no difference in NT-proBNP levels between survivors and non-survivors. NT-proBNP levels were significantly higher in group A at 6 h (p = 0.007), 12 h (p = 0.036), and 24 h (p = 0.007), but not at birth (p = 0.785) or 48 h (p = 0.15) compared to group B.

CONCLUSION

NT-proBNP analysis in the first 48 h of life may be useful to assess PH and cardiac dysfunction in CDH newborns and to predict the need for ECMO support.

Left-sided congenital diaphragmatic hernia: can we improve survival while decreasing ECMO?

BACKGROUND

Mortality and ECMO rates for congenital diaphragmatic hernia (CDH) remain ~30%. In 2016, we changed our CDH guidelines to minimize stimulation while relying on preductal oxygen saturation, lower mean airway pressures, stricter criteria for nitric oxide (iNO), and inotrope use. We compared rates of ECMO, survival, and survival without ECMO between the two epochs.

DESIGN/METHODS

Retrospective review of left-sided CDH neonates at the University of Utah/Primary Children's Hospital NICUs during pre (2003-2015, n = 163) and post (2016-2019, n = 53) epochs was conducted. Regression analysis controlled for defect size and intra-thoracic liver.

RESULTS

Following guideline changes, we identified a decrease in ECMO (37 to 13%; p = 0.001) and an increase in survival without ECMO (53 to 79%, p = 0.0001). Overall survival increased from 74 to 89% (p = 0.035).

CONCLUSION(S)

CDH management guideline changes focusing on minimizing stimulation, using preductal saturation and less aggressive ventilator/inotrope support were associated with decreased ECMO use and improved survival.

Inhaled Nitric Oxide Is Associated with Improved Oxygenation in a Subpopulation of Infants with Congenital Diaphragmatic Hernia and Pulmonary Hypertension

OBJECTIVES

To determine which patients with congenital diaphragmatic hernia (CDH) and pulmonary hypertension (PH) benefit from inhaled nitric oxide (iNO) treatment by comparing characteristics and outcomes of iNO responders to nonresponders.

STUDY DESIGN

We performed a retrospective chart review of infants with CDH treated at our center between 2011 and 2016. In a subset of patients, iNO was initiated for hypoxemia or echocardiographic evidence of extrapulmonary right to left shunting. Initial post-treatment blood gases were reviewed, and patients were classified as responders (increased PaO₂ >20 mm Hg) or nonresponders. Baseline characteristics, echocardiograms and outcomes were compared between groups with Fisher exact tests and Mann-Whitney t tests, as appropriate.

RESULTS

During the study period, 95 of 131 patients with CDH (73%) were treated with iNO. All patients with pretreatment echocardiograms (n = 90) had echocardiographic evidence of PH. Thirty-eight (40%) patients met treatment response criteria. Responders had significant improvements in PaO₂ (51 ± 3 vs 123 ± 7 mm Hg, P < .01), alveolar-arterial gradient (422 ± 30 vs 327 ± 27 mm Hg, P < .01), and PaO₂ to FiO₂ ratio (82 ± 10 vs 199 ± 15 mm Hg, P < .01). Nonresponders were more likely to have left ventricular systolic dysfunction (27% vs 8%, P = .03) on echocardiogram. Responders were less likely to require extracorporeal membrane support (50 vs 24%, P = .02).

CONCLUSIONS

iNO treatment is associated with improved oxygenation and reduced need for ECMO in a subpopulation of patients with CDH with PH and normal left ventricular systolic function.

Implications of Atrial-Level Shunting by Echocardiography in Newborns with Congenital Diaphragmatic Hernia

OBJECTIVE

To determine whether postnatal echocardiographic indices of left ventricular (LV) size and function are associated with atrial-level shunt direction and investigate whether a relationship exists between LV function and LV size in patients with congenital diaphragmatic hernia (CDH).

STUDY DESIGN

This was a single-center retrospective study of 51 neonates with CDH evaluated at Children's Hospital Colorado. Initial postnatal echocardiograms were analyzed for cardiac dimensions, valvar integrity, cardiac time intervals, and biventricular function. Comparisons were made between neonates with left-to-right vs right-to-left atrial-level shunting, as well as between those with decreased (ejection fraction <55%) vs normal (ejection fraction ≥55%) LV function.

RESULTS

The majority (82.4%) of infants with CDH had a left-to-right atrial-level shunt, and 84.3% had systemic or suprasystemic pulmonary artery pressure. Decreased LV function was demonstrated in 37.2% and was associated with smaller LV volumes and worse outcomes, including the need for extracorporeal membrane oxygenation (ECMO) and survival.

CONCLUSIONS

Left-to-right atrial-level shunting is common in neonates with severe CDH, even in the presence of suprasystemic pulmonary artery pressure. LV dysfunction correlates with decreased LV volumes and is associated with adverse neonatal outcomes, including increased need for ECMO and decreased survival.

Left ventricular cardiac output is a reliable predictor of extracorporeal life support in neonates with congenital diaphragmatic hernia

OBJECTIVE

Congenital diaphragmatic hernia (CDH) is a treatable condition but despite optimal management, some patients require extracorporeal life support (ECLS). This study evaluates the association of left ventricular (LV) cardiac output and the need for ECLS.

STUDY DESIGN

Single center, retrospective chart review from 1/1/2012 through 7/1/2018. Twenty-seven patients met criteria for evaluation with six patients (22%) requiring ECLS. Echocardiography was used to assess ventricular function.

RESULTS

There was a statistically significant decrease in LV cardiac index of 1.33 L /min/m² vs 1.80 L /min/m² (p = 0.04) for patients requiring ECLS and non-ECLS, respectively. There was no difference between the 2 groups with regards to vasoactive medication use, surfactant use, iNO use, severity of pulmonary hypertension, or right ventricular (RV) function.

CONCLUSION

In newborns with CDH, decreased LV cardiac output is more strongly associated with need for ECLS than severity of pulmonary hypertension or RV dysfunction.

Early Postnatal Ventricular Dysfunction Is Associated with Disease Severity in Patients with Congenital Diaphragmatic Hernia

OBJECTIVE

To assess patterns of postnatal ventricular function and their relationship to prenatal and postnatal markers of disease severity in infants with congenital diaphragmatic hernia (CDH).

STUDY DESIGN

In this observational case-control study of cardiac function in infants with CDH in the first 5 days of life, systolic and diastolic function in the right ventricle (RV) and left ventricle (LV) were assessed using speckle tracking echocardiography-derived global strain and tissue Doppler imaging. Correlation between cardiac function and prenatal observed:expected total fetal lung volume (TFLV), oxygenation index (OI), duration of intubation, and hospital length of stay were assessed.

RESULTS

All measures of systolic and diastolic function were significantly reduced in the CDH group (n = 25) compared with controls (n = 20) at <48 hours, and were improved by 72-120 hours. LV global systolic longitudinal strain (GLS) correlated with prenatal TFLV (R² = 0.32; P = .03), OI (R² = 0.35; P < .001), duration of intubation (R² = 0.24; P = .04), and length of stay (R² = 0.4; P = .006). Mean (SD) LV GLS at <48 hours was significantly lower in infants with CDH who did not survive and/or required ECMO compared with those who did not: -11.5 (5.3)% vs -16.9 (5.3)% (P = .02).

CONCLUSIONS

RV and LV function are impaired in the transitional period in infants with CDH. Early LV systolic function correlates with prenatal and postnatal markers of clinical disease severity and may be an important determinant of disease severity and therapeutic target in CDH. These findings support regular assessment of cardiac function in CDH and investigational trials of targeted cardiovascular therapies.

Effects of Simvastatin on Fetal Cardiac Impairment in the Diaphragmatic Experimental Hernia Model

BACKGROUND

Statins and sildenafil have been shown to exert beneficial effects in cardiac injury. We hypothesized that antenatal maternal administration of simvastatin and/or sildenafil might also promote benefits in cardiac remodeling of congenital diaphragmatic hernia (CDH). Therefore, we performed micro-CT image analysis and histology of the heart after antennal treatment in experimental nitrofen-induced CDH.

METHODS

At 9.5 days post conception (dpc), pregnant rats were exposed to nitrofen. At 16 and 20 dpc fetuses were treated with simvastatin and/or sildenafil. At 21 dpc postmortem micro-CT and autopsy were performed.

RESULTS

All nitrofen-treated fetuses had a lower birth weight compared to controls; in the simvastatin-treated group, a significant improvement in CDH was noted. Impairment of the lung and liver was also noted in CDH. Compared to controls, CDH rats showed lower ventricular mass, with greater left ventricular thickness; simvastatin decreased the ventricular mass and improved wall thickness. CDH rats exhibited myocardial hypotrophy, severe vascular depression in the left ventricle, and intense interstitial edema compared to controls and nitrofen-exposed animals without CDH. In CDH, the cardiac morphology appeared deformed with left ventricular wall verticalization. Simvastatin improved cardiac myocyte appearance and heart morphology.

CONCLUSION

The potential to treat CDH with antenatal simvastatin may improve the management of this malformation.

Assessment of Carina Position Antenatally and Postnatally in Infants with Congenital Diaphragmatic Hernia

OBJECTIVE

To determine whether endotracheal tube (ETT) insertion depth should be modified in infants with congenital diaphragmatic hernia (CDH) to reduce the risk of main-stem intubation.

STUDY DESIGN

The distance from the thoracic inlet to the carina was measured antenatally by fetal magnetic resonance imaging (MRI) between 20-28 weeks' (early) and 30-34 weeks' (late) gestation in 30 infants with CDH and compared with 12 early and 36 late MRIs in control infants without CDH. Postnatal tube position was assessed by chest radiograph in the same 30 infants with CDH and compared with 20 control infants with postnatal birth depression.

RESULTS

The carina position was displaced upward in fetuses and newborns with CDH. Distance from the thoracic inlet to the carina compared with controls was 1.04 ± 0.1 cm vs 1.42 ± 0.07 cm on early MRI (P < .05), 1.43 ± 0.14 cm vs 1.9 ± 0.04 cm on late MRI (P < .01), and 2.36 ± 0.07 cm vs 3.28 ± 0.05 cm on postnatal radiographs (P < .01). Adjusting the ETT depth by 1 cm resulted in a median distance of 1.27 cm from the tip of the ETT to the carina.

CONCLUSION

Cephalad displacement of the carina in infants with CDH may predispose them to right main-stem intubation and subsequent development of pneumothorax. We speculate that modifying the ETT insertion depth to 5.5 cm + weight in newborns born at term may prevent pneumothoraces and improve outcomes for infants with CDH.

Milrinone in congenital diaphragmatic hernia - a randomized pilot trial: study protocol, review of literature and survey of current practices

Background

Congenital diaphragmatic hernia (CDH) is commonly associated with pulmonary hypoplasia and pulmonary hypertension (PH). PH associated with CDH (CDH-PH) is frequently resistant to conventional pulmonary vasodilator therapy including inhaled nitric oxide (iNO) possibly due to right and left ventricular dysfunction. Milrinone is an intravenous inotrope and lusitrope with pulmonary vasodilator properties and has been shown anecdotally to improve oxygenation in PH. We developed this pilot study to determine if milrinone infusion would improve oxygenation in neonates ≥36 weeks postmenstrual age (PMA) with CDH.

Methods/design

Data on pulmonary vasodilator management and outcome of CDH patients was collected from 18 university NICUs affiliated with the Neonatal Research Network (NRN) from 2011 to 2012. The proposed pilot will be a masked, placebo–controlled, multicenter, randomized trial of 66 infants with CDH with an oxygenation index (OI) ≥10 or oxygen saturation index (OSI) ≥5. The primary outcome is the oxygenation response, as determined by change in OI at 24 h after initiation of study drug. As secondary outcomes, we will determine oxygenation at 48 h and 72 h post-infusion, right ventricular pressures on echocardiogram and the incidence of systemic hypotension, arrhythmias, intracranial hemorrhage, survival without extracorporeal membrane oxygenation, and chronic lung disease (oxygen need at 28 days postnatal age). Finally, we will evaluate the pulmonary and nutritional status at 4, 8 and 12 months of age using a phone questionnaire.

Results

Three hundred thirty-seven infants with CDH were admitted to NRN NICUs in 2011 and 2012 of which 275 were ≥36 weeks PMA and were exposed to the following pulmonary vasodilators: iNO (39%), sildenafil (17%), milrinone (17%), inhaled epoprostenol (6%), intravenous epoprostenol (3%), and intravenous PGE1 (1%). ECMO was required in 36% of patients. Survival to discharge was 71%.

Discussion

CDH is an orphan disease with high mortality with few randomized trials evaluating postnatal management. Intravenous milrinone is a commonly used medication in neonatal/pediatric intensive care units and is currently used in 17% of patients with CDH within the NRN. This pilot study will provide data and enable further studies evaluating pulmonary vasodilator therapy in CDH.

Trial registration

ClinicalTrials.gov; NCT02951130; registered 14 October 2016.

Congenital diaphragmatic hernias: from genes to mechanisms to therapies

Congenital diaphragmatic hernias (CDHs) and structural anomalies of the diaphragm are a common class of congenital birth defects that are associated with significant morbidity and mortality due to associated pulmonary hypoplasia, pulmonary hypertension and heart failure. In ∼30% of CDH patients, genomic analyses have identified a range of genetic defects, including chromosomal anomalies, copy number variants and sequence variants. The affected genes identified in CDH patients include transcription factors, such as GATA4, ZFPM2, NR2F2 and WT1, and signaling pathway components, including members of the retinoic acid pathway. Mutations in these genes affect diaphragm development and can have pleiotropic effects on pulmonary and cardiac development. New therapies, including fetal endoscopic tracheal occlusion and prenatal transplacental fetal treatments, aim to normalize lung development and pulmonary vascular tone to prevent and treat lung hypoplasia and pulmonary hypertension, respectively. Studies of the association between particular genetic mutations and clinical outcomes should allow us to better understand the origin of this birth defect and to improve our ability to predict and identify patients most likely to benefit from specialized treatment strategies.

Cardiac dysfunction in congenital diaphragmatic hernia: Pathophysiology, clinical assessment, and management

Cardiac dysfunction is an important consequence of pulmonary hypertension in congenital diaphragmatic hernia and a determinant of disease severity. Increased afterload leads to right ventricular dilatation and diastolic dysfunction. Septal displacement and dysfunction impair left ventricular function, which may also be compromised by fetal hypoplasia. Biventricular failure contributes to systemic hypotension and hypoperfusion. Early and regular echocardiographic assessment of cardiac function and pulmonary artery pressure can guide therapeutic decision-making, including choice and timing of pulmonary vasodilators, cardiotropes, ECMO, and surgery.

Fetal left-sided cardiac structural dimensions in left-sided congenital diaphragmatic hernia - association with severity and impact on postnatal outcomes

OBJECTIVES

Fetuses with congenital diaphragmatic hernia (CDH) demonstrate varying degrees of left heart hypoplasia. Our study assesses the relationship between fetal left-sided cardiac structural dimensions, lung size, percentage liver herniation, lung-to-head ratio, postnatal left-sided cardiac structural dimensions, and postnatal outcomes.

METHODS

We performed a retrospective cohort study of fetuses with left-sided CDH who had prenatal echocardiographic, ultrasound, and magnetic resonance imaging examinations at our institution between January 2007 and March 2015. Postnatal outcomes assessed include use of inhaled nitric oxide (iNO), use of extracorporeal membrane oxygenation, and death.

RESULTS

Fifty-two fetuses with isolated left-sided CDH were included. Multivariate logistic regression models indicated that smaller fetal aortic valve z-score was associated with postnatal use of iNO (p = 0.03). Fetal mitral valve z-score correlated with lung-to-head ratio (p = 0.04), postnatal mitral valve z-score correlated with percent liver herniation (p = 0.03), and postnatal left ventricular end-diastolic dimension z-score correlated with liver herniation <20% (p = 0.04).

CONCLUSION

We identified associations between smaller fetal left-sided cardiac structural dimensions and classic CDH indices. Smaller aortic valve z-score was associated with iNO use; however, left heart dimensions showed no association with extracorporeal membrane oxygenation or mortality. Further study into the impact of left-sided hypoplasia on outcomes in CDH is worthy of evaluation in a larger, prospective study. © 2017 John Wiley & Sons, Ltd.

Congenital Diaphragmatic hernia - a review

Congenital Diaphragmatic hernia (CDH) is a condition characterized by a defect in the diaphragm leading to protrusion of abdominal contents into the thoracic cavity interfering with normal development of the lungs. The defect may range from a small aperture in the posterior muscle rim to complete absence of diaphragm.

The pathophysiology of CDH is a combination of lung hypoplasia and immaturity associated with persistent pulmonary hypertension of newborn (PPHN) and cardiac dysfunction. Prenatal assessment of lung to head ratio (LHR) and position of the liver by ultrasound are used to diagnose and predict outcomes. Delivery of infants with CDH is recommended close to term gestation. Immediate management at birth includes bowel decompression, avoidance of mask ventilation and endotracheal tube placement if required. The main focus of management includes gentle ventilation, hemodynamic monitoring and treatment of pulmonary hypertension followed by surgery. Although inhaled nitric oxide is not approved by FDA for the treatment of PPHN induced by CDH, it is commonly used.

Extracorporeal membrane oxygenation (ECMO) is typically considered after failure of conventional medical management for infants ≥ 34 weeks’ gestation or with weight >2 kg with CDH and no associated major lethal anomalies. Multiple factors such as prematurity, associated abnormalities, severity of PPHN, type of repair and need for ECMO can affect the survival of an infant with CDH. With advances in the management of CDH, the overall survival has improved and has been reported to be 70-90% in non-ECMO infants and up to 50% in infants who undergo ECMO.

Short-term weight gain velocity in infants with congenital diaphragmatic hernia (CDH)

BACKGROUND

Appropriate post-natal growth remains a mainstay of therapeutic goals for infants with CDH, with the hypothesis that optimizing linear growth will improve survival through functional improvements in pulmonary hypoplasia. However, descriptions of growth and the effect on survival are limited in affected infants.

OBJECTIVE

Describe in-hospital weight gain related to survival among infants with CDH.

DESIGN/METHODS

Children's Hospitals Neonatal Database (CHND) identified infants with CDH born ≥34weeks' gestation (2010-14). Exclusion criteria were: admission age>7days, death/discharge age<14days, or surgical CDH repair prior to admission. Weight gain velocity (WGV: g/kg/day) was calculated using an established exponential approximation and the cohort stratified by Q1: <25%ile, Q2-3: 25-75%ile, and Q4: >75%ile. Descriptive measures and unadjusted Kaplan-Meier analyses describe the implications of WGV on mortality/discharge.

RESULTS

In 630 eligible infants, median WGV was 4.6g/kg/day. After stratification by WGV [Q1: (n=156; <3.1g/kg/day); Q2-3 (n=316; 3.1-5.9g/kg/day), and Q4 (n=158, >5.9g/kg/day)] infants in Q1 had shortest median length of stay, less time on TPN and intervention for gastro-esophageal reflux relative to the other WGV strata (p<0.01 for all). Unadjusted survival estimates revealed that Q1 [hazard ratio (HR)=9.5, 95% CI: 5.7, 15.8] and Q4 [HR=2.9, 95% CI: 1.7, 5.1, p<0.001 for both] WGV were strongly associated with NICU mortality relative to Q2-3 WGV.

CONCLUSION

Variable WGV is evident in infants with CDH. Highest and lowest WGV appear to be related to adverse outcomes. Efforts are needed to develop nutritional strategies targeting optimal growth.

The Upturned Superior Mesenteric Artery Sign for First-Trimester Detection of Congenital Diaphragmatic Hernia and Omphalocele

OBJECTIVES

The aim of this study was to follow the course of the superior mesenteric artery (SMA) in first-trimester fetuses to predict the location of the small bowel. Its abnormal course aids in early detection of congenital diaphragmatic hernia (CDH) and assessment of the contents of omphalocele.

METHODS

The SMA can be easily identified in a sagittal section of the fetus by using color Doppler sonography at the 11- to 14-week scan, and normally, it has a downward course caudally to supply the intestines. The course of the SMA points to the location of the bowel.

RESULTS

We report a series of 7 cases detected in first trimester with an abnormal course of the SMA, 3 of which had CDH and 4 of which had omphalocele. In CDH, the intestines herniate into the thoracic cavity; hence, the SMA tends to have an upward course toward the thorax. In 4 cases of omphalocele, the SMA follows the exteriorized bowel into the base of the umbilical cord.

CONCLUSIONS

Second-trimester sonography for detection of congenital malformations is a standardized protocol, but a careful anatomic survey at the 11- to 14-week scan is often rewarding. When there is a suspicion of an intrathoracic mass or a mediastinal shift, the upturned course of SMA serves as a valuable sign in confirmation of CDH. Chromosomal abnormalities are often reported in cases of omphalocele containing small bowel only, and the upward course of the SMA toward the base of the cord helps in its early prenatal diagnosis, which facilitates early genetic assessment in these fetuses.

Differences in preductal and postductal arterial blood gas measurements in infants with severe congenital diaphragmatic hernia

OBJECTIVE

To determine whether right-to-left shunting across the ductus arteriosus (DA) in patients with congenital diaphragmatic hernia (CDH) with suprasystemic pulmonary hypertension (PH) results in differences between preductal and postductal arterial blood gas (ABG) measurements.

DESIGN

Demographics, baseline echocardiographic parameters and differences in simultaneous right upper extremity (preductal) and umbilical artery (postductal) ABG samples were determined in newborns with PH and CDH.

SETTING

Newborn intensive care unit at Children's Hospital Colorado.

PATIENTS

30 newborns with CDH and systemic or suprasystemic PH.

INTERVENTIONS

Simultaneous preductal and postductal ABGs were compared in 30 newborns with PH and CDH, and ventilator settings and fraction of inspired oxygen (FiO2) were adjusted based on preductal ABG samples. Differences in respiratory support before and after obtaining preductal ABG samples were compared.

RESULTS

All patients had severe PH by echocardiogram with right-to-left DA shunting. However, only two newborns (6.6%) had right-to-left shunting across the foramen ovale. When compared with postductal ABG samples, preductal arterial pH was 7.35±0.02 vs 7.30±0.02, PaCO2 40.8±1.9 vs 48.3±1.9, PaO2 99.3±7.8 vs 46±3, oxygen saturation 95.6±1.2 vs 85.2±1.7 and oxygenation index 14.1±2.3 vs 30.1±5.1 (p<0.05 for all comparisons). Targeting preductal ABG measurements allowed for significant weaning of FiO2.

CONCLUSIONS

Right-to-left DA shunting decreases postductal PaO2, oxygen saturation and pH, and increases PaCO2. Targeting preductal ABG measurements may allow for a more physiological approach to ventilator management, and potentially reduce lung injury.

Myocardial effects of fetal endoscopic tracheal occlusion in lambs with CDH

INTRODUCTION

Fetal endoscopic tracheal occlusion in congenital diaphragmatic hernia (CDH) may reduce pulmonary hypertension and ameliorate postnatal cardiac output. The effects of sustained early (ETO) and late (LTO) tracheal occlusion on left ventricular (LV) cells in the lamb model have not been described.

MATERIALS AND METHODS

CDH was created in lambs at 70 days' gestation (term = 145 days). ETO (85 days) or LTO (105 days) was sustained till term. After cesarean section (140 days) fetuses were euthanized and hearts harvested. LV myocardial cells were studied by histological and immunofluorescence (TGF-beta 1, endothelin-1) assays in CDH, ETO, LTO, and the control group (two subjects per group). Small intramyocardial arteries were evaluated by traditional histology.

RESULTS

LV myocardial histology in CDH and LTO was similar. ETO-induced LV myocardial cell enlargement and increased endothelin-1 and TGF-beta 1 staining; a weaker immunofluorescence signal was observed in LTO compared with ETO. Myocardial vascular wall thickness was greater in CDH than in controls. ETO was associated with a vascular wall thickness within the range of controls.

CONCLUSION

With only two fetuses in each group, only an explorative evaluation was possible. The time point at which TO is performed seems to have an effect on cardiac morphology. Functional studies as well as confirmation in clinical samples are mandatory.

Severe left diaphragmatic hernia limits size of fetal left heart more than does right diaphragmatic hernia

OBJECTIVES

To assess whether severity of congenital diaphragmatic hernia (CDH) correlates with the degree of left heart hypoplasia and left ventricle (LV) output, and to determine if factors leading to abnormal fetal hemodynamics, such as compression and reduced LV preload, contribute to left heart hypoplasia.

METHODS

This was a retrospective cross-sectional study of fetuses at 16-37 weeks' gestation that were diagnosed with CDH between 2000 and 2010. Lung-to-head ratio (LHR), liver position and side of the hernia were determined from stored ultrasound images. CDH severity was dichotomized based on LHR and liver position. The dimensions of mitral (MV) and aortic (AV) valves and LV were measured, and right and left ventricular outputs were recorded.

RESULTS

In total, 188 fetuses with CDH were included in the study, 171 with left CDH and 17 with right CDH. Fetuses with severe left CDH had a smaller MV (Z = -2.24 ± 1.3 vs -1.33 ± 1.08), AV (Z = -1.39 ± 1.21 vs -0.51 ± 1.05) and LV volume (Z = -4.23 ± -2.71 vs -2.08 ± 3.15) and had lower LV output (26 ± 10% vs 32 ± 10%) than those with mild CDH. MV and AV in fetuses with right CDH (MV, Z = -0.83 ± 1.19 and AV, Z = -0.71 ± 1.07) were larger than those in fetuses with left CDH, but LV outputs were similarly diminished, regardless of hernia side. Severe dextroposition and abnormal liver position were associated independently with smaller left heart, while LHR was not.

CONCLUSION

The severity of left heart hypoplasia correlates with the severity of CDH. Altered fetal hemodynamics, leading to decreased LV output, occurs in both right- and left-sided CDH, but the additional compressive effect on the left heart is seen only when the hernia is left-sided. Improved knowledge of the physiology of this disease may lead to advances in therapy and better risk assessment for use in counseling affected families.

Early neonatal echocardiographic findings in an experimental rabbit model of congenital diaphragmatic hernia

This study aimed to demonstrate that congenital diaphragmatic hernia (CDH) results in vascular abnormalities that are directly associated with the severity of pulmonary hypoplasia and hypertension. These events increase right ventricle (RV) afterload and may adversely affect disease management and patient survival. Our objective was to investigate cardiac function, specifically right ventricular changes, immediately after birth and relate them to myocardial histological findings in a CDH model. Pregnant New Zealand rabbits underwent the surgical procedure at 25 days of gestation (n=14). CDH was created in one fetus per horn (n=16), and the other fetuses were used as controls (n=20). At term (30 days), fetuses were removed, immediately dried and weighed before undergoing four-parameter echocardiography. The lungs and the heart were removed, weighed, and histologically analyzed. CDH animals had smaller total lung weight (P<0.005), left lung weight (P<0.005), and lung-to-body ratio (P<0.005). Echocardiography revealed a smaller left-to-right ventricle ratio (LV/RV, P<0.005) and larger diastolic right ventricle size (DRVS, P<0.007). Histologic analysis revealed a larger number of myocytes undergoing mitotic division (186 vs 132, P<0.05) in CDH hearts. Immediate RV dilation of CDH hearts is related to myocyte mitosis increase. This information may aid the design of future strategies to address pulmonary hypertension in CDH.

Acute Neonatal Respiratory Failure

Acute respiratory failure requiring assisted ventilation is one of the most common reasons for admission to the neonatal intensive care unit. Respiratory failure is the inability to maintain either normal delivery of oxygen to the tissues or normal removal of carbon dioxide from the tissues. It occurs when there is an imbalance between the respiratory workload and ventilatory strength and endurance. Definitions are somewhat arbitrary but suggested laboratory criteria for respiratory failure include two or more of the following: PaCO₂ > 60 mmHg, PaO₂ < 50 mmHg or O₂ saturation <80 % with an FiO₂ of 1.0 and pH < 7.25 (Wen et al. 2004).

Outcome of congenital diaphragmatic hernia with indication for Fontan procedure

BACKGROUND

The aim of this study was to clarify the outcome of patients with cardiovascular malformation (CVM) among those with congenital diaphragmatic hernia (CDH) who are indicated for the Fontan procedure.

METHODS

The subjects included 76 CDH patients with CVM recruited from a national survey of 614 CDH patients. The outcomes were evaluated between two groups divided according to indication for the Fontan procedure. Patients with functional univentricular disease were considered to be candidates for the Fontan procedure.

RESULTS

Sixteen (21.1%) of the 76 patients were candidates for the Fontan procedure, accounting for 2.6% of all 614 patients with CDH. None of these patients, however, underwent the Fontan procedure. Among the 16 patients, the absence of obstruction of the left ventricular outflow tract (LVOTO) was significantly associated with better 90 day survival (71.4%, 5/7, for those without LVOTO vs 0.0%, 0/9, for those with LVOTO, P = 0.0007). After excluding 22 patients with chromosomal and/or genetic abnormalities or syndromes, the 90 day survival rate was significantly better in neonates without than with indication for the Fontan procedure (62.5%, 25/40 vs 28.6%, 4/14, P = 0.0271).

CONCLUSIONS

Patients with indications for the Fontan procedure are rare, and the outcome of patients with LVOTO among those with CDH is especially poor.

Vasopressin improves hemodynamic status in infants with congenital diaphragmatic hernia

OBJECTIVE

To assess the ability of vasopressin to stabilize hemodynamics in infants with systemic hypotension secondary to congenital diaphragmatic hernia (CDH).

STUDY DESIGN

A retrospective chart review was performed to identify 13 patients with CDH treated with vasopressin for refractory hypotension to assess the effect of vasopressin on pulmonary and systemic hemodynamics and gas exchange in this setting. Data collected included demographics, respiratory support, inotropic agents, pulmonary and systemic hemodynamics, urine output, and serum and urine sodium levels during vasopressin therapy.

RESULTS

Vasopressin therapy increased mean arterial pressure and decreased pulmonary/systemic pressure ratio, heart rate, and fraction of inspired oxygen. In 6 of 13 patients, extracorporeal membrane oxygenation therapy was no longer indicated after treatment with vasopressin. Improvement in left ventricular function and oxygenation index after vasopressin initiation was associated with a decreased need for extracorporeal membrane oxygenation therapy. Prolonged vasopressin treatment was associated with hyponatremia, increased urine output, and increased urine sodium.

CONCLUSIONS

Vasopressin stabilized systemic hemodynamics without adverse effects on pulmonary hemodynamics in a subset of infants with CDH. Our results suggest a potential role for vasopressin therapy in patients with CDH with catecholamine-resistant refractory hypotension.

Clinical characteristics and outcomes of patients with cardiac defects and congenital diaphragmatic hernia

OBJECTIVE

To evaluate the impact of associated heart defects on outcomes to discharge, and identify factors affecting survival of all infants born with congenital diaphragmatic hernia (CDH) in last decade using Congenital Diaphragmatic Hernia Study Group data.

STUDY DESIGN

This was a retrospective review of all infants with CDH enrolled in Congenital Diaphragmatic Hernia Study Group database from January 2000 to December 2010. The study cohort was divided into 3 groups (GRP): GRP 1, CDH with major heart defects; GRP 2, CDH with minor heart defects; and GRP 3, CDH with no reported heart defects.

RESULTS

The 4268 enrolled infants included 345 (8%) in GRP 1, 412 (10%) in GRP 2, and 3511 (82%) in GRP 3. Survival was significantly lower in GRP 1 compared with GRP 2 and GRP 3 (36% vs 73%). In GRP 1, the most common defects were left heart obstructive lesions (34%). Survival was lowest in infants with transposition of great arteries (0%) and single ventricle physiology (16%). There was no change in survival rate for any group between 2000-2005 and 2006-2010. In GRP 1, factors that predicted lower survival were birth weight <2.5 kg, associated noncardiac anomalies, single ventricle physiology, no sildenafil therapy, no CDH repair, and no cardiac repair.

CONCLUSION

Survival is significantly lower in patients with CDH and major heart defects compared with patients with minor or no heart defects. Outcomes of newborns with CDH and major heart defects have not improved over the last decade.

The pulmonary circulation in neonatal respiratory failure

The pulmonary circulation rapidly adapts at birth to establish lungs as the site of gas exchange. Abnormal transition at birth and/or parenchymal lung disease can result in neonatal hypoxemic respiratory failure. This article reviews the functional changes in pulmonary hemodynamics and structural changes in pulmonary vasculature secondary to (1) normal and abnormal transition at birth, and (2) diseases associated with neonatal hypoxemic respiratory failure. Various management strategies to correct respiratory failure are also discussed.

Right- versus left-sided congenital diaphragmatic hernia: postnatal outcome at a specialized tertiary care center

OBJECTIVE

To systematically investigate the impact of the location of the defect in congenital diaphragmatic hernia on neonatal mortality and morbidity with a special focus on survival at discharge, extracorporeal membrane oxygenation requirement, and the development of chronic lung disease.

DESIGN

Retrospective tertiary care center study with a matched-pair analysis of all fetuses that were treated for congenital diaphragmatic hernia between 2004 and 2009.

SETTING

A specialized tertiary care center for fetuses with congenital diaphragmatic hernia.

PATIENTS

Complete sets of data were available for 106 patients with congenital diaphragmatic hernia. For 17 of 18 infants with right-sided congenital diaphragmatic hernia we were able to allocate infants with left-sided congenital diaphragmatic hernia with no relevant difference in previously described prognostic factors, such as pulmonary hypoplasia and liver herniation.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

There was a strong trend toward better survival in infants with right-sided congenital diaphragmatic hernia than with left-sided congenital diaphragmatic hernia (94% vs. 70%; p = .07). More neonates with left-sided congenital diaphragmatic hernia died of severe pulmonary hypertension despite extracorporeal membrane oxygenation. Fewer neonates with right-sided congenital diaphragmatic hernia died, yet higher degrees of pulmonary hypoplasia and oxygen requirement were observed despite extracorporeal membrane oxygenation.

CONCLUSIONS

In congenital diaphragmatic hernia, the location of the defect has a substantial impact on postnatal survival and the development of chronic lung disease. In left-sided congenital diaphragmatic hernia, pulmonary hypertension resistant to therapeutic management, including extracorporeal membrane oxygenation, is more common and is associated with a higher rate of neonatal demise. Right-sided congenital diaphragmatic hernia infants have an increased benefit from extracorporeal membrane oxygenation but the better survival entails a higher rate of chronic lung disease.

Significance and outcome of left heart hypoplasia in fetal congenital diaphragmatic hernia

OBJECTIVE

In patients with a left-sided congenital diaphragmatic hernia (CDH), the left ventricle (LV) is often compressed and smaller than normal. The objective of this study was to investigate whether small left heart dimensions prenatally normalize after birth in patients with CDH, or whether prenatal indices of left heart size and flow predict postnatal outcome.

METHODS

Clinical and echocardiographic data were reviewed for patients diagnosed with left-sided CDH prenatally. Cardiac dimensions and flows were compared with normative data. Among liveborn patients, pre- and postnatal Z-scores of left heart structures were compared, and associations between prenatal indices and outcome were assessed.

RESULTS

Of 125 patients diagnosed prenatally with CDH, 111 had a left-sided defect. Of these, 85 were liveborn, including 20 with congenital heart disease. Gestational age-adjusted dimensions of fetal left heart structures, including aortic valve diameter, mitral valve (MV) diameter, LV long-axis, LV short-axis and LV volume, were all smaller than normal (P < 0.001). On average, the LV contributed 33 +/- 8% of combined ventricular output, lower than the normal 40-50%. Z-scores of left heart structures increased from the prenatal echocardiogram to the postnatal study, with average changes ranging from 0.56 +/- 1.68 (aortic valve) to 1.39 +/- 1.85 (LV volume). Among liveborn patients, there was no association between prenatal left heart Z-scores and postnatal survival.

CONCLUSIONS

Hypoplasia of and reduced flow through the left heart are common among fetuses with CDH. After birth and CDH repair, left heart dimensions generally normalize, with adequate size to support a biventricular circulation, even when there is very low flow through the left heart in mid- and late-gestation.

CONTEMPORARY NEONATAL INTENSIVE CARE MANAGEMENT IN CONGENITAL DIAPHRAGMATIC HERNIA: DOES THIS OBVIATE THE NEED FOR FETAL THERAPY?

The management of congenital diaphragmatic hernia (CDH) in the newborn infant has changed radically since the first successful outcomes were reported 60 years ago. Then it seemed a surgical problem with a surgical solution – do an operation, remove the intestines and solid viscera from the thoracic cavity, repair the defect and allow the lung to expand. CDH in that era was regarded as the quintessential neonatal surgical emergency. The expectation was that urgent surgery would result in improvement in lung function and oxygenation. That approach persisted up to the 1980s when it was realized that the problem was far more complex and involved both an abnormal pulmonary vascular bed as well as pulmonary hypoplasia. The use of systemically delivered pulmonary vasodilator therapy, principally tolazoline, became a focus of interest in the 1980s with small case reports and case series suggesting improved survival. In the 1990s, based on studies that showed worsening thoracic compliance and gas exchange following surgical repair, deferred surgery and pre-operative stabilization became the standard of care. At the same time extracorporeal membrane oxygenation (ECMO) was increasingly used either as part of pre-operative stabilization or as a rescue therapy after repair. Other centres chose to use high frequency oscillatory ventilation (HFOV). Despite all these innovations the survival in live born infants with CDH did not improve to more than 50% in large series published from high volume centres. However, in the past 10 years there has been an appreciable improvement in survival to the extent that many centres are now reporting survival rates of greater than 80%. Probably the biggest impact on this improvement has been the recognition of the role that ventilation induced lung injury plays in mortality and the need for ECMO rescue. This has ushered in an era of a lung protective or “gentle ventilation” strategy which has been widely adopted as a standard approach. While there have been these radical changes in postnatal management attempts have been made to improve outcome with prenatal interventions, starting with prenatal repair, which was abandoned because of preterm labour. More recently there has been increasing experience in the use of balloon occlusion of the trachea as a prenatal intervention strategy with patients being selected based on prenatal predictors of poor outcome. This approach can only be justified if those predictors can be validated and the outcomes (death or serious long term morbidity) can be shown to be better than those currently achievable, namely 80% survival in high volume CDH centres rather than the 50–60% survival frequently quoted in historical papers.

Congenital diaphragamatic hernia associated with aortic coarctation: a case report

Congenital diaphragmatic hernia associated with cardiac anomalies is a major therapeutic challenge. We report a case of Congenital diaphragmatic hernia associated with coarctation of the aorta.

Congenital diaphragmatic hernia: a systematic review and summary of best-evidence practice strategies

OBJECTIVES

Recent reports suggest that specific care strategies improve survival of infants with congenital diaphragmatic hernia (CDH). This review presents details of care from centers reporting high rates of survival among CDH infants.

STUDY DESIGN

We conducted a MEDLINE search (1995 to 2006) and searched all citations in the Cochrane Central Register of Controlled Trials. Studies were included if they contained reports of >20 infants with symptomatic CDH, and >75% survival of isolated CDH.

RESULT

Thirteen reports from 11 centers met inclusion criteria. Overall survival, including infants with multiple anomalies, was 603/763 (79%; range: 69 to 93%). Survival for isolated CDH was 560/661 (85%; range: 78 to 96%). The frequency of extracorporeal membrane oxygenation (ECMO) use for isolated CDH varied widely among reporting centers 251/622 (40%; range: 11 to 61%), as did survival for infants with isolated CDH placed on ECMO: 149/206 (73%; range: 33 to 86%). There was no suggestion of benefit from use of antenatal glucocorticoids given after 34 weeks gestation or use of postnatal surfactant. Low mortality was frequently attributed to minimizing lung injury and adhering to center-specific criteria for ECMO.

CONCLUSION

Use of strategies aimed at minimizing lung injury, tolerance of postductal acidosis and hypoxemia, and adhering to center-specific criteria for ECMO were strategies most consistently reported by successful centers. The literature lacks randomized clinical trials of these or other care strategies in this complex patient population; prospective studies of safety and long-term outcome are needed.

Predictors of outcome in patients with congenital diaphragmatic hernia requiring extracorporeal membrane oxygenation

BACKGROUND

The role of extracorporeal membrane oxygenation (ECMO) in patients with congenital diaphragmatic hernia is still evolving. The use of ECMO is invasive with potential complications during instrumentation for cannulation and heparinization. There are no reliable predictors of outcome in patients requiring ECMO. We aimed to identify (a) the factors that could predict outcome and (b) the incidence and relation of complications during ECMO to outcome.

METHODS

"Pre" ECMO (age, sex, birth weight, blood gasses, and ventilator settings) and "on" ECMO variables (mode of ECMO, use of nitric oxide, surfactant, liquid ventilation, inotropes, timing of repair, and complications on ECMO) were analyzed to identify predictors of outcome.

RESULTS

Fifty-two patients were included. The overall survival was 58%. Mean duration of ECMO (181 +/- 120 vs 317 +/- 156 hours, P = .001), use of nitric oxide (6 vs 10, P = .049), and renal complications (4 vs 14; P < .001) differed between survivors and nonsurvivors. The survival of patients requiring ECMO support for more than 2 weeks is significantly lower than that of patients requiring ECMO support for less than 2 weeks (18% vs 68%, P = .005). Multiple logistic regression revealed ECMO duration of 2 weeks or more and renal complications to be associated with mortality.

CONCLUSION

No pre-ECMO variable could be identified as predictor of mortality. Prolonged duration of ECMO and renal complications on ECMO were independently associated with mortality.

Myocardium expression of connexin 43, SERCA2a, and myosin heavy chain isoforms are preserved in nitrofen-induced congenital diaphragmatic hernia rat model

BACKGROUND

Previous morphological studies had produced controversial results with regard to heart development in congenital diaphragmatic hernia (CDH), whereas a few publications investigated cardiac function and myocardial maturation. Myocardium maturation is associated with age-dependent increasing of gene expression of gap junction protein connexin 43 (Cx43), adenosine triphosphatase of the sarcoplasmic reticulum (SERCA2a), as well as switching of myosin heavy chains (MHCs) from beta to alpha isoforms. Our aim was to evaluate myocardium maturity in nitrofen-induced CDH rat model.

METHODS

Fetuses from dated pregnant Sprague-Dawley rats were assigned to 3 experimental groups: control, nitrofen (exposed to nitrofen, without CDH), and CDH (exposed to nitrofen, with CDH). Myocardial samples collected from left ventricle free wall were processed to (i) quantification of messenger RNA (mRNA) of Cx43, SERCA2a, alpha and beta MHC isoforms, as well as beta-actin (housekeeping gene); and (ii) separation of MHC isoforms (alpha and beta isoforms) by sodium dodecyl sulfate polyacrylamide gel electrophoresis silver stained.

RESULTS

We demonstrated that there is no difference in myocardial gene expression of Cx43 (control, 1.0 +/- 0.1; nitrofen, 1.1 +/- 0.2; CDH, 1.3 +/- 0.2) and SERCA2a (control, 1.0 +/- 0.1; nitrofen, 0.9 +/- 0.1; CDH, 1.0 +/- 0.2). Myocardial gene expressions of alpha and beta mRNA of MHC isoforms were slightly decreased both in nitrofen and CDH fetuses when compared with control fetuses, but evaluation of the alpha-to-beta ratios of MHC isoforms at protein level revealed no significant differences between CDH and control (control, 16.9 +/- 2.5; CDH, 17.0 +/- 2.0).

CONCLUSIONS

Myocardial quantification of Cx43 and SERCA2a mRNA, as well as the expression pattern of MHC isoforms at protein levels, was similar in all studied groups. We predict, therefore, that acute heart failure commonly observed in CDH infants might be attributed predominantly to cardiac overload secondary to severe pulmonary hypertension rather than to myocardial immaturity.

Expression of Connexin 43 in the hearts of rat embryos exposed to nitrofen and effects of vitamin A on it

Rats with experimental congenital diaphragmatic hernia (CDH) have heart hypoplasia and conotruncal and great vessel malformations that are likely related to disturbed neural crest developmental control. Neural crest cells communicate through intercellular gap junctions whose main protein is Connexin 43 (Cx43). The migration and participation of neural crest cells in heart development is likely influenced by this protein which might be also directly involved in myocardial development. Vitamin A is beneficial for heart hypoplasia in CDH rats. The aims of this study were to examine the status of Cx43 in the heart of embryonal rats exposed to nitrofen and to assess if vitamin A reverts these effects. Pregnant rats received either 100 mg nitrofen or olive oil on E9.5. Each group was divided into two subgroups according to the subsequent treatment with intragastric vitamin A (15,000 i.u.) or vehicle on E10.5 and E11.5. The pups were recovered on E13, E15, and E21 and the hearts were dissected out and pooled. Cx43 mRNA expression was determined by quantitative real-time PCR. Comparisons among groups were made with ANOVA and Bonferroni post hoc tests with a threshold of significance of P<0.05. In control rats Cx43 mRNA was minimally expressed on E13 and E15 and fully expressed on E21. Nitrofen significantly increased Cx43 mRNA on E15. Additional treatment with vitamin A tended to moderate this increase on E15. Cx43 was overexpressed in the hearts of nitrofen-exposed embryonal rats on day E15 of gestation. Vitamin A tended to normalize this expression. The mechanism of action of Cx43 deserves further investigation.

Effects of prenatal vitamins A, E, and C on the hypoplastic hearts of fetal rats with diaphragmatic hernia

BACKGROUND/AIM

Nitrofen induces heart hypoplasia together with congenital diaphragmatic hernia (CDH) in rats. Intracellular oxidative stress might be one of the mechanisms of action of the teratogen, and vitamin A has been shown to reverse in part these effects when administered simultaneously or shortly after it. This study aims at testing the hypothesis that vitamin A and other antioxidant vitamins, such as E and C, could improve myocardial development even when administered late in gestation, a likely useful period for prenatal medication.

MATERIAL AND METHODS

Time-mated Sprague-Dawley female rats were exposed to either vehicle (control) or 100 mg of nitrofen (experimental) on day 9.5 of gestation. In 3 additional groups, the animals were exposed to vitamin A (total 15000 IU), vitamin E (total 150 IU), or vitamin C (total 150 IU) on days 16, 17, and 18. The fetuses were recovered on day 21, and randomly selected hearts of those with CDH were processed for histologic studies (hematoxylin-eosin and periodic acid-Schiff stainings), DNA and protein contents, and ki-67 (proliferation) and terminal deoxynucleotidyl transferase-mediated dUTP-biotin end labeling (apoptosis) studies. The differences among groups were assessed by analysis of variance with Bonferroni/Dunn post hoc tests and a threshold of significance of P < .05.

RESULTS

Nitrofen induced heart hypoplasia in terms of decreased heart/body weight, cell mass (less DNA and protein), and proportion of proliferating cells with increased apoptosis. Vitamin C alleviated weight hypoplasia and the 3 vitamins were able to restore cell mass and to reestablish near-normal figures of proliferation and apoptosis.

CONCLUSIONS

Antioxidant vitamins A, E, and C given late in gestation alleviate heart hypoplasia that accompanies CDH in the rat model. This timing suggests that the beneficial effects are exerted on the maturational phase of development.

Cardiac anomalies in patients with congenital diaphragmatic hernia and their prognosis: a report from the Congenital Diaphragmatic Hernia Study Group

BACKGROUND/PURPOSE

Patients with congenital diaphragmatic hernia (CDH) are known to have associated cardiac anomalies. Data from the Congenital Diaphragmatic Hernia Study Group has allowed better definition of the types of heart defects (HDs) and survival for these patients.

METHODS

Since 1995, 2636 patients were enrolled in the Congenital Diaphragmatic Hernia Study Group from 82 centers. Patients with hemodynamically significant HD, excluding patent ductus arteriosus (PDA); patent foramen ovale (PFO); and atrial septal defect (ASD), were selected. Cardiac anatomy and survival data for all patients were reviewed.

RESULTS

Two hundred eighty (10.6%) patients had significant HDs: ventricular septal defect (VSD); (42.2%), aortic arch obstruction (15%), univentricular anatomy (13.9%), tetralogy of Fallot variants (11.1%), total anomalous pulmonary venous return (3.9%), double outlet right ventricle (RV) (3.2%), pulmonary stenosis (2.5%), transposition of the great arteries (2.5%), and various other defects in 5.7%. Survival for the entire group was 67.1%; survival for patients without HD was 70.2% and for patients with HD was 41.1% (P < .001). Patients with biventricular cardiac anatomy had a 47% survival, whereas those with univentricular anatomy had a 5% survival (P < .001).

CONCLUSION

Significant HD is associated with 10.6% of CDH. Survival for patients with HD is significantly lower than for patients with normal cardiac anatomy. Patients with CDH and univentricular cardiac anatomy have a poor prognosis.

Pulmonary vasodilator therapy in congenital diaphragmatic hernia: acute, late, and chronic pulmonary hypertension

Pulmonary hypertension complicates the course of many newborns with congenital diaphragmatic hernia. In the most severe cases, the fetal condition of markedly elevated pulmonary vascular resistance persists after birth and is associated with hypoxemic respiratory failure and severe disturbances in cardiac performance. Late pulmonary hypertension (weeks to months after birth) is increasingly recognized in this population, and chronic pulmonary vascular abnormalities (months to years after birth) are now being discovered. In this review, we will discuss the pathophysiology of acute, late, and chronic pulmonary hypertension in patients with congenital diaphragmatic hernia. We will also review the role of currently available pulmonary vasoactive drugs in the management of pulmonary hypertension in this population.