Diprosopus: Systematic review and report of two cases

BACKGROUND

Diprosopus is a subtype of symmetric conjoined twins with one head, facial duplication and a single trunk. Diprosopus is a very rare congenital anomaly.

METHODS

This is a systematic review of published cases and the presentation of two new cases born in Argentina. We estimated the prevalence of conjoined twins and diprosopus using data from the National Network of Congenital Anomalies of Argentina (RENAC).

RESULTS

The prevalence of conjoined twins in RENAC was 19 per 1,000,000 births (95% confidence interval, 12-29). Diprosopus prevalence was 2 per 1,000,000 births (95% confidence interval, 0.2-6.8). In the systematic review, we identified 31 diprosopus cases. The facial structures more frequently duplicated were nose and eyes. Most frequent associated anomalies were: anencephaly, duplication of cerebral hemispheres, craniorachischisis, oral clefts, spinal abnormalities, congenital heart defects, diaphragmatic hernia, thoracic and/or abdominal visceral laterality anomalies. One of the RENAC cases and three cases from the literature had another discordant nonmalformed twin.

CONCLUSION

The conjoined twins prevalence was similar to other studies. The prevalence of diprosopus was higher. The etiology is still unknown. The presence of visceral laterality anomalies may indicate the link between diprosopus and the alteration or duplication of the primitive node in the perigastrulation period (12-15 days postfertilization). Pregnancies of more than two embryos may be a risk factor for diprosopus. Given the low prevalence of this defect, it would be useful to perform studies involving several surveillance systems and international consortiums. Birth Defects Research (Part A), 2016. © 2016 Wiley Periodicals, Inc. Birth Defects Research (Part A) 106:993-1007, 2016. © 2016 Wiley Periodicals, Inc.

Anesthetic Challenges and Management in a case of Jarcho-Levin Syndrome with a Neural Tube Defect in a Newborn

Jarcho-Levin syndrome (JLS) is a rare axial skeletal growth disorder characterized by the presence of multi-level costovertebral malformations, a short neck, a short trunk, and kyphoscoliosis at birth. Neural tube defects appear to be common findings in patients with JLS, and chest hypoplasia frequently leads to respiratory insufficiency and death in early childhood. There have been no previous studies in the literature on the anesthetic management of JLS with neural tube defects and hydrocephalus. Therefore, we have reported a case of JLS in a female full-term newborn, who underwent surgery for myelomeningocele repair and ventriculoperitoneal shunting, with the associated anesthetic challenges and their management.

Thoracoscopic Approach for Repair of Diaphragmatic Hernia Occurring After Pediatric Liver Transplant

Diaphragmatic hernias (DH) occurring after pediatric liver transplantation (LT) are rare. However, such complications have been previously reported in the literature and treatment has always been surgical repair via laparotomy. We report our experience of minimally invasive thoracoscopic approach for repair of DH occurring after LT in pediatric recipients.From April 2010 to December 2014, 7 cases of DH were identified in pediatric LT recipient in Samsung Medical Center. Thoracoscopic repair was attempted in 3 patients. Patients' medical records were retrospectively reviewed.Case 1 was a 12-month-old boy, having received deceased donor LT for biliary atresia (BA) 5 months ago. He presented with dyspnea and left-sided DH was detected. Thoracoscopic repair was successfully done and the boy was discharged at postoperative day 7. Case 2 was a 13-month-old boy, having received deceased donor LT for BA 2 months ago. He presented with vomiting and right-sided DH was detected. Thoracoscopic repair was done along with primary repair of herniated small bowel that was perforated while attempting reduction into the peritoneal cavity. The boy recovered from the surgery without complications and was discharged on the 10th postoperative day. Case 3 was a 43-month-old girl, having received deceased donor LT for Alagille syndrome 28 months ago. She was diagnosed with right-sided DH during steroid pulse therapy for acute rejection. Thoracoscopic repair was attempted but a segment of necrotic bowel was noticed along with bile colored pleural effusion and severe adhesion in the thoracic cavity. She received DH repair with small bowel resection and anastomosis via laparotomy.Thoracoscopic repair was attempted in 3 cases of DH occurring after LT in pediatric recipients. With experience and expertise in pediatric minimally invasive surgery, thoracoscopic approach is feasible in this rare population of patients.

Pulmonary artery endothelial cell dysfunction and decreased populations of highly proliferative endothelial cells in experimental congenital diaphragmatic hernia

Decreased lung vascular growth and pulmonary hypertension contribute to poor outcomes in congenital diaphragmatic hernia (CDH). Mechanisms that impair angiogenesis in CDH are poorly understood. We hypothesize that decreased vessel growth in CDH is caused by pulmonary artery endothelial cell (PAEC) dysfunction with loss of a highly proliferative population of PAECs (HP-PAEC). PAECs were harvested from near-term fetal sheep that underwent surgical disruption of the diaphragm at 60-70 days gestational age. Highly proliferative potential was measured via single cell assay. PAEC function was assessed by assays of growth and tube formation and response to known proangiogenic stimuli, vascular endothelial growth factor (VEGF), and nitric oxide (NO). Western blot analysis was used to measure content of angiogenic proteins, and superoxide production was assessed. By single cell assay, the proportion of HP-PAEC with growth of >1,000 cells was markedly reduced in the CDH PAEC, from 29% (controls) to 1% (CDH) (P < 0.0001). Compared with controls, CDH PAEC growth and tube formation were decreased by 31% (P = 0.012) and 54% (P < 0.001), respectively. VEGF and NO treatments increased CDH PAEC growth and tube formation. VEGF and VEGF-R2 proteins were increased in CDH PAEC; however, eNOS and extracellular superoxide dismutase proteins were decreased by 29 and 88%, respectively. We conclude that surgically induced CDH in fetal sheep causes endothelial dysfunction and marked reduction of the HP-PAEC population. We speculate that this CDH PAEC phenotype contributes to impaired vascular growth in CDH.

Diagnosis and treatment of pulmonary hypertension in infancy

Normal pulmonary vascular development in infancy requires maintenance of low pulmonary vascular resistance after birth, and is necessary for normal lung function and growth. The developing lung is subject to multiple genetic, pathological and/or environmental influences that can adversely affect lung adaptation, development, and growth, leading to pulmonary hypertension. New classifications of pulmonary hypertension are beginning to account for these diverse phenotypes, and or pulmonary hypertension in infants due to PPHN, congenital diaphragmatic hernia, and bronchopulmonary dysplasia (BPD). The most effective pharmacotherapeutic strategies for infants with PPHN are directed at selective reduction of PVR, and take advantage of a rapidly advancing understanding of the altered signaling pathways in the remodeled vasculature.

Early fetoscopic tracheal occlusion for extremely severe pulmonary hypoplasia in isolated congenital diaphragmatic hernia: preliminary results

OBJECTIVE

To evaluate the effect of early fetoscopic tracheal occlusion (FETO) (22-24 weeks' gestation) on pulmonary response and neonatal survival in cases of extremely severe isolated congenital diaphragmatic hernia (CDH).

METHODS

This was a multicenter study involving fetuses with extremely severe CDH (lung-to-head ratio < 0.70, liver herniation into the thoracic cavity and no other detectable anomalies). Between August 2010 and December 2011, eight fetuses underwent early FETO. Data were compared with nine fetuses that underwent standard FETO and 10 without fetoscopic procedure from January 2006 to July 2010. FETO was performed under maternal epidural anesthesia, supplemented with fetal intramuscular anesthesia. Fetal lung size and vascularity were evaluated by ultrasound before and every 2 weeks after FETO. Postnatal therapy was equivalent for both treated fetuses and controls. Primary outcome was infant survival to 180 days and secondary outcome was fetal pulmonary response.

RESULTS

Maternal and fetal demographic characteristics and obstetric complications were similar in the three groups (P > 0.05). Infant survival rate was significantly higher in the early FETO group (62.5%) compared with the standard group (11.1%) and with controls (0%) (P < 0.01). Early FETO resulted in a significant improvement in fetal lung size and pulmonary vascularity when compared with standard FETO (P < 0.01).

CONCLUSIONS

Early FETO may improve infant survival by further increases of lung size and pulmonary vascularity in cases with extremely severe pulmonary hypoplasia in isolated CDH. This study supports formal testing of the hypothesis with a randomized controlled trial.

Predictors of neonatal morbidity in fetuses with severe isolated congenital diaphragmatic hernia undergoing fetoscopic tracheal occlusion

OBJECTIVES

To investigate neonatal morbidity in fetuses with severe congenital diaphragmatic hernia (CDH) treated with fetoscopic endoluminal tracheal occlusion (FETO) and compare it with historical controls with less severe forms of CDH that were managed expectantly.

METHODS

This was a prospective, multicenter study on neonatal outcomes and prenatal predictors in 90 FETO survivors (78 left-sided, 12 right) and 41 controls from the antenatal CDH registry with either severe or moderate hypoplasia who were managed expectantly. We also investigated early neonatal morbidity indicators, including the need for patch repair, duration of mechanical ventilation and supplemental oxygen, age at full enteral feeding and incidence of pulmonary hypertension.

RESULTS

Gestational age at delivery was predictive of duration of assisted ventilation (P = 0.046), days on supplemental oxygen (P = 0.019) and age at full enteral feeding (P = 0.020). When delivery took place after 34 weeks' gestation, neonatal morbidity of FETO cases was comparable with that of expectantly managed cases with moderate hypoplasia.

CONCLUSIONS

Fetal intervention for severe CDH is associated with neonatal morbidity that is comparable with that of an expectantly managed group with less severe disease.

A simplified formula using early blood gas analysis can predict survival outcomes and the requirements for extracorporeal membrane oxygenation in congenital diaphragmatic hernia

The aims of this study were to investigate whether early arterial blood gas analysis (ABGA) could define the severity of disease in infants with congenital diaphragmatic hernia (CDH). We conducted a retrospective study over a 21-yr period of infants diagnosed with CDH. Outcomes were defined as death before discharge, and extracorporeal membrane oxygenation requirements (ECMO) or death. A total 114 infants were included in this study. We investigated whether simplified prediction formula [PO2-PCO2] values at 0, 4, 8, and 12 hr after birth were associated with mortality, and ECMO or death. The area under curve (AUC) of receiver operating characteristic curve was used to determine the optimum ABGA values for predicting outcomes. The value of [PO2-PCO2] at birth was the best predictor of mortality (AUC 0.803, P < 0.001) and at 4 hr after birth was the most reliable predictor of ECMO or death (AUC 0.777, P < 0.001). The value of [PO2-PCO2] from ABGA early period after birth can reliably predict outcomes in infants with CDH.

Spatiotemporal disorder in the axial skeleton development of the Mesp2-null mouse: a model of spondylocostal dysostosis and spondylothoracic dysostosis

Spondylocostal dysostosis (SCDO) is a genetic disorder characterized by severe malformation of the axial skeleton. Mesp2 encodes a basic helix-loop-helix type transcription factor that is required for somite formation. Its human homologue, Mesp2, is a gene affected in patients with SCDO and a related vertebral disorder, spondylothoracic dysostosis (STDO). This work investigated how the loss of Mesp2 affects axial skeleton development and causes the clinical features of SCDO and STDO. We first confirmed, by three-dimensional computed tomography scanning, that Mesp2-null mice exhibited mineralized tissue patterning resembling the radiological features of SCDO and STDO. Histological observations and in situ hybridization probing for extracellular matrix molecules demonstrated that the developing vertebral bodies in Mesp2-null mice were extensively fused with rare insertions of intervertebral tissue. Unexpectedly, the intervertebral tissues were mostly fused longitudinally in the vertebral column, instead of exhibiting extended formation, as was expected based on the caudalized properties of Mesp2-null somite derivatives. Furthermore, the differentiation of vertebral body chondrocytes in Mesp2-null mice was spatially disordered and largely delayed, with an increased cell proliferation rate. The quantitative three-dimensional immunofluorescence image analyses of phospho-Smad2 and -Smad1/5/8 revealed that these chondrogenic phenotypes were associated with spatially disordered inputs of TGF-β and BMP signaling in the Mesp2-null chondrocytes, and also demonstrated an amorphous arrangement of cells with distinct properties. Furthermore, a significant delay in ossification in Mesp2-null vertebrae was observed by peripheral quantitative computed tomography. The current observations of the spatiotemporal disorder of vertebral organogenesis in the Mesp2-null mice provide further insight into the pathogenesis of SCDO and STDO, and the physiological development of the axial skeleton.

[Surgery of the diaphragm in the planned thoracic surgery]

122 patients with different diseases of the diaphragm were operated on during 1963-2011 yy. The majority of patients - 76 (62.3%) - had hernias of the weak phrenic zones. 14 (11.5%) and 17 (14.0%) patients had posttraumatic hernia and phrenic relaxation, respectively. The majority of patients had no complaints and the disease was diagnosed on the X-ray examination. Rarely, the compression syndrome, caused by the translocation of the bowel into the thoracic cavity, was registered. That clinically emerged as short breath, heaviness sensation and cardiac rhythm disorders. The worked out reconstructive operations allow to cure such patients with minimal risk.

Deficiency of FRAS1-related extracellular matrix 1 (FREM1) causes congenital diaphragmatic hernia in humans and mice

Congenital diaphragmatic hernia (CDH) is a common life-threatening birth defect. Recessive mutations in the FRAS1-related extracellular matrix 1 (FREM1) gene have been shown to cause bifid nose with or without anorectal and renal anomalies (BNAR) syndrome and Manitoba oculotrichoanal (MOTA) syndrome, but have not been previously implicated in the development of CDH. We have identified a female child with an isolated left-sided posterolateral CDH covered by a membranous sac who had no features suggestive of BNAR or MOTA syndromes. This child carries a maternally-inherited ~86 kb FREM1 deletion that affects the expression of FREM1's full-length transcripts and a paternally-inherited splice site mutation that causes activation of a cryptic splice site, leading to a shift in the reading frame and premature termination of all forms of the FREM1 protein. This suggests that recessive FREM1 mutations can cause isolated CDH in humans. Further evidence for the role of FREM1 in the development of CDH comes from an N-ethyl-N-nitrosourea -derived mouse strain, eyes2, which has a homozygous truncating mutation in Frem1. Frem1(eyes2) mice have eye defects, renal agenesis and develop retrosternal diaphragmatic hernias which are covered by a membranous sac. We confirmed that Frem1 is expressed in the anterior portion of the developing diaphragm and found that Frem1(eyes2) embryos had decreased levels of cell proliferation in their developing diaphragms when compared to wild-type embryos. We conclude that FREM1 plays a critical role in the development of the diaphragm and that FREM1 deficiency can cause CDH in both humans and mice.

Sonographic assessment of fetal cardiac function: indirect measurements of fetal cardiac function, newer techniques and clinical applications

Noninvasive blood flow measurements based on Doppler ultrasound studies are the main clinical tool for studying the cardiovascular status of fetuses at risk for circulatory compromise. Usually, qualitative analysis of peripheral arteries and in particular clinical situations such as severe growth restriction or volume overload also of venous vessels close to the heart or of flow patterns in the heart is being used to gauge the level of compensation in a fetus. However, quantitative assessment of the driving force of the fetal circulation, the cardiac output remains an elusive goal in fetal medicine. This article reviews the methods for direct and indirect assessment of cardiac function and explains new clinical applications. Part 1 of this review describes the concept of cardiac function and cardiac output and the techniques that have been used to quantify output. Part 2 summarizes the use of arterial and venous Doppler studies in the fetus and gives a detailed description of indirect measurements of cardiac function (like indices derived from the duration of segments of the cardiac cycle) with current examples of their application.

A randomized controlled trial of fetal endoscopic tracheal occlusion versus postnatal management of severe isolated congenital diaphragmatic hernia

OBJECTIVE

Severe pulmonary hypoplasia and pulmonary arterial hypertension are associated with reduced survival in congenital diaphragmatic hernia (CDH). We aimed to determine whether fetal endoscopic tracheal occlusion (FETO) improves survival in cases of severe isolated CDH.

METHODS

Between May 2008 and July 2010, patients whose fetuses had severe isolated CDH (lung-to-head ratio < 1.0, liver herniation into the thoracic cavity and no other detectable anomalies) were assigned randomly to FETO or to no fetal intervention (controls). FETO was performed under maternal epidural anesthesia supplemented with fetal intramuscular anesthesia. Tracheal balloon placement was achieved with ultrasound guidance and fetoscopy between 26 and 30 weeks of gestation. All cases that underwent FETO were delivered by the EXIT procedure. Postnatal therapy was the same for both treated fetuses and controls. The primary outcome was survival to 6 months of age. Other maternal and neonatal outcomes were also evaluated.

RESULTS

Twenty patients were enrolled randomly to FETO and 21 patients to standard postnatal management. The mean gestational age at randomization was similar in both groups (P = 0.83). Delivery occurred at 35.6 ± 2.4 weeks in the FETO group and at 37.4 ± 1.9 weeks in the controls (P < 0.01). In the intention-to-treat analysis, 10/20 (50.0%) infants in the FETO group survived, while 1/21 (4.8%) controls survived (relative risk (RR), 10.5 (95% CI, 1.5-74.7), P < 0.01). In the received-treatment analysis, 10/19 (52.6%) infants in the FETO group and 1/19 (5.3%) controls survived (RR, 10.0 (95% CI, 1.4-70.6) P < 0.01).

CONCLUSION

FETO improves neonatal survival in cases with isolated severe CDH.

The right ventricular systolic to diastolic duration ratio: a simple prognostic marker in congenital diaphragmatic hernia?

AIMS

(i) To compare the ratio of right ventricular systolic to diastolic duration (SD/DD) in infants with congenital diaphragmatic hernia (CDH) and normal controls and (ii) to examine its association, if any, with outcomes in CDH.

METHODS

  Retrospective chart and echocardiographic review of consecutive neonates (<1 month old) with CDH and term controls without structural heart defects. Right ventricular SD/DD was calculated by a single reader.

RESULTS

Infants with CDH (n = 29) were comparable to controls (n = 27) in their mean (SD) age [2.2 (3.3) vs. 2 (4.0) days], birthweight [3 (0.67) vs. 3 (0.69) kg] and proportion of males (48.2% vs. 72.4%). The DD and SD/DD were significantly abnormal in the CDH group, compared to controls. Among infants with CDH, those who died (n = 15) and those who died or required ECMO (n = 17) had significantly shorter DD and higher SD/DD ratio. At a cut-off of 1.3, SD/DD ratio had a sensitivity of 92.8 (95% CI 64-99%) and specificity of 61.5 (32-85%) for prediction of mortality. Significant independent associations with mortality were observed with antenatal diagnosis (p = 0.003) and higher SD/DD ratio (p = 0.04).

CONCLUSION

The right ventricular SD/DD ratio is a sensitive objective prognostic marker in infants with CDH. Further studies incorporating SD/DD ratio as a guide to intervention are warranted.

Laparoscopic repair of late presenting congenital Bochdalek diaphragmatic hernia

Bochdalek diaphragmatic hernia is a common congenital anomaly presenting in the neonatal period and managed by open surgical procedures. Late presentation is usually associated with better prognosis. Here a case of a 10 years old boy presenting with Bochdalek hernia, managed primarily by laparoscopic approach is reported.

Perioperative course of pulmonary hypertension in infants with congenital diaphragmatic hernia: impact on outcome following successful repair

BACKGROUND

Pulmonary hypertension (PH) associated with congenital diaphragmatic hernia (CDH) remains a significant cause of morbidity and mortality. For improved outcomes, preoperative stabilization is commonly practiced to control the PH in infants with CDH. Some CDH infants who have been considered stabilized and ready for surgery have nevertheless developed significant PH after surgical repair. In fact, the markers and consequences of the preoperative stabilization are still unclear. Therefore, we examine the perioperative course of PH to evaluate the impact of preoperative PH severity on mortality and morbidity of infants who underwent surgical repair of CDH.

METHODS

The medical charts of all newborns (n = 49) with CDH who were treated at our institution between January 2000 and December 2009 were reviewed. General management and perioperative data were evaluated for all infants. The ratio of estimated pulmonary artery pressure to systemic pressure (P/S ratio or PSR), based on echocardiographic data, was used to assess the PH severity during the perioperative period.

RESULTS

The overall survival rate in our group of infants with CDH was 71.4%. Of the 49 infants with CDH, 9 (18.4%) died during the preoperative phase. Forty infants underwent CDH repair at a median age of 3.5 days (range, 1-46 days). Five of these infants (12.5%) subsequently deteriorated and died after surgery. Using receiver operating characteristic curve analysis, a PSR cutoff value before surgery of 0.9 predicted mortality in CDH infants with a sensitivity of 100% and specificity of 84% and with an area under the curve of 0.93 (P = .002). Accordingly, 2 groups of infants with distinct outcomes were identified, as follows: a low-PSR cohort (PSR ≤0.9) with a survival rate of 100% and a high-PSR cohort (PSR >0.9) with a survival rate of 50% (P = .001). The rate of pneumothorax and the frequency of use of several inotropic agents after surgery were significantly higher in the high-PSR group (P = .001 and .007, respectively). Compared with low-PSR infants, infants with high PSR were operated on later (P = .03) and were postoperatively ventilated longer (P = .01). During the entire perioperative period, significant differences in the PH severity were noted between the 2 PSR groups. During the first week of life, infants in the high-PSR group had significantly higher PSRs than those in the low-PSR group (P = .001); and similar tendencies continued to be significant between the 2 groups after CDH repair (P = .04).

CONCLUSIONS

During the perioperative period, PH severity monitoring via the serial assessment of PSR is beneficial. Better outcomes were observed with a preoperative PSR less than or equal to 0.9, and this association needs to be confirmed by prospective study.

Fetal cerebral blood flow velocities in congenital diaphragmatic hernia

OBJECTIVES

Left ventricular cardiac output is decreased in fetuses with congenital diaphragmatic hernia (CDH). Our aim was to assess whether this alters cerebral perfusion or growth in utero.

METHODS

Fetal head circumference, biparietal diameter, lung-to-head ratio and middle cerebral artery (MCA) Doppler flow patterns were assessed by ultrasonography in 103 fetuses with prenatally diagnosed CDH. Total fetal lung volume and cerebral volume were measured using magnetic resonance imaging. Values were transformed to gestational age-independent scores (multiples of the median (MoM)) and compared with controls. Subanalyses were made according to whether the CDH was left- (n = 86) or right-sided (n = 17) and to whether it was isolated (n = 86) or associated with other anomalies (n = 17).

RESULTS

MCA flow velocity was significantly lower in fetuses with CDH than in healthy fetuses (0.79 ± 0.19 MoM; P < 0.0001) but MCA pulsatility index was unchanged (0.99 ± 0.25 MoM; P = 0.79). Cranial biometry and cerebral volume in CDH fetuses fell in the normal range. Gestational age-adjusted lung area was correlated with MCA peak systolic velocity, which was in turn correlated with brain volume.

CONCLUSIONS

Fetal cerebral blood flow velocities are decreased in CDH yet cranial and cerebral growth are conserved. Further work will be needed to address whether part of the neurologic impairment observed in long-term survivors of CDH finds its origin in the prenatal period.

Motor-function and exercise capacity in children with major anatomical congenital anomalies: an evaluation at 5 years of age

BACKGROUND

Children with major anatomical congenital anomalies (CA) often need prolonged hospitalization with surgical interventions in the neonatal period and thereafter. Better intensive care treatment has reduced mortality rates, but at the cost of more morbidity.

AIM

To study motor-function and exercise capacity in five-year-old children born with CA, and to determine whether motor-function and exercise capacity differ according to primary diagnosis.

STUDY DESIGN

Descriptive study.

SUBJECTS

One-hundred-and-two children with the following CA: congenital diaphragmatic hernia (CDH) n=24, esophageal atresia (EA) n=29, small intestinal anomalies (SIA) n=25, and abdominal wall defects (AWD) n=24.

OUTCOME MEASURES

Overall and subtest percentile scores of the Movement-Assessment Battery for Children (M-ABC) were used to measure motor skills. Endurance time on the Bruce treadmill test was used to determine maximal exercise capacity.

RESULTS

Motor-function: Seventy-three children (71.6%) had an overall percentile score within the normal range, 18 (17.6%) were classified as borderline, and 11 (10.8%) had a motor problem. This distribution was different from that in the reference population (Chi square: p=0.001). Most problems were encountered in children with CDH and EA (p=0.001 and 0.013, respectively). Ball skills and balance were most affected. Exercise capacity: Mean standard deviation score (SDS) endurance time=-0.5 (SD: 1.3); p=0.001; due to poor exercise performance in CDH and EA patients.

CONCLUSIONS

Children with major anatomical CA and especially those with CDH and EA are at risk for delayed motor-function and disturbed exercise capacity.

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.

Left ventricular cardiac function in fetuses with congenital diaphragmatic hernia and the effect of fetal endoscopic tracheal occlusion

OBJECTIVES

The pre-existing compression of the left ventricle in congenital diaphragmatic hernia (CDH) could be aggravated by the amplified lung growth after fetoscopic endoluminal tracheal occlusion (FETO). Our aim was to document left ventricular (LV) size and function in fetuses with isolated left-sided CDH and to document the effect of FETO on the fetal heart.

METHODS

We determined cardiac axis, LV diameters, ejection fraction, shortening fraction, mitral E/A index and myocardial performance index (MPI) in 27 fetuses with isolated left-sided CDH, and compared these with values in a reference population (n = 117). In fetuses with severe CDH that subsequently underwent FETO and/or reversal of occlusion, additional measurements were obtained 24 h before and after each fetal intervention. We recorded fetal electrocardiograms non-invasively in six CDH fetuses and compared the duration of the QRS complex with data obtained from 12 controls.

RESULTS

LV end-diastolic diameter was 32% smaller in CDH fetuses than in controls (P < 0.0001) but LV function was comparable. QRS duration was no different between CDH and control fetuses. FETO did not affect cardiac size but reduced the MPI (P = 0.004). Reversal of FETO had no significant effect on cardiac size and function.

CONCLUSIONS

CDH fetuses have a smaller left ventricle than do healthy fetuses. There is no overall adverse impact of CDH and FETO on LV cardiac function.

[Effect of hemin on the lung development and pulmonary arterial structural remodeling in congenital diaphragmatic hernia: experiment with rats]

OBJECTIVE

To assay the effects of prenatal hemin therapy on pulmonary hypoplasia (PH) and pulmonary arterial structural remodeling in congenital diaphragmatic hernia (CDH).

METHODS

Six pregnant female SD rats were randomly divided into 3 equal groups: control group, undergoing gastric perfusion of olive oil once on day 9.5 and intraperitoneal injection of normal saline on days 11-14; CDH group, undergoing gastric perfusion of nitrofen 125 mg once on day 9.5 and intraperitoneal injection of normal saline on days 11-14; and hemin group, undergoing gastric perfusion of nitrofen 125 mg once on day 9.5 and intraperitoneal injection of hemin 15 mg x kg(-1) x d(-1) on days 11-14. On the gestational day 21 caesarean section was performed to take out the fetuses to undergo histological examination and image analysis.

RESULTS

CDH were detected in 28 of the 44 (63.6%) fetuses from the 2 groups receiving nitrofen. The lungs of all CDH group fetuses were hypoplastic, and the fetuses of the hemin group showed improved lung development. The right lung/body weight ratio and pulmonary alveolar area ratio (PAA%) of the hemin group were (16.6 +/- 1.0) mg/g and (45 +/- 6)% respectively, both significantly higher than those of the CDH group [(14.6 +/- 1.7) mg/g and (28 +/- 6)% respectively, P = 0.03 and P < 0.01]. The alveolar septum area ratio (ASA%) of the hemin group was (44 +/- 6)%, significantly lower than that of the CDH group [(64 +/- 8)%, P < 0. 01]. The media thickness percentages (MT%) of pre-acinar artery (PAPA) and intra-acinar artery (IAPA) of the fetuses of the hemin group were (21.2 +/- 2.2)% and (18.2 +/- 2.1)% respectively, both significantly lower than those of the CDH group [(24.3 +/- 4.0)% and (21.9 +/- 3.9)% respectively, both P < 0.05], which were significantly higher than those of the control group [(20.0 +/- 2.4)% and (17.2 +/- 2.3)% respectively, both P < 0.01]. The component ratio of nonmuscularized artery (NMA) in the IAPA level of the hemin group was (78.2 +/- 3.0)%, significantly higher than that of the CDH group [(72.8 +/- 3.2)%, P = 0.001].

CONCLUSION

PH and pulmonary arterial structural remodeling are present in CDH. Although prenatal administration of hemin cannot prevent the genesis of CDH in rats, it may improve the pulmonary development, inhibit medial hypertrophy, and reduce the percentage of muscularized IAPA.

Lung volumes and distribution of ventilation in survivors to congenital diaphragmatic hernia (CDH) during infancy

The assessment of lung volumes, particularly functional residual capacity (FRC), is crucial for understanding lung development during infancy in CDH patients.

AIM

To evaluate changes in lung function during infancy in subjects with CDH treated with a "gentle ventilation" technique and delayed surgery strategy in the neonatal period.

METHODS

13 CDH infants were studied twice and compared with a population of 28 healthy infants (HI). Tidal-Volume (Vt), respiratory rate (RR) and time to peak expiratory flow/expiratory time ratio (tPTEF/Te) were measured with an ultrasonic flow meter; Compliance (Crs) and Resistance (Rrs) of the respiratory system were studied with the single occlusion technique; FRC and Lung Clearance Index (LCI), were assessed with the sulfur hexafluoride (SF6) wash-in/wash-out technique. The differences between the first (T1) and second (T2) measurement in the CDH group were assessed by the Student's t-test for paired values. For each set of measurement (T1 and T2) the values were compared with HI by Student's t-test.

RESULTS

Mean age at test was 7.5 +/- 5.2 months for HI, 4.5 +/- 2.5 at T1 and 11.9 +/- 4.5 months at T2 for CDH infants. At T1 there were no significant differences between CDH infants and HI in Vt, Crs, and FRC, while tPTEF/te ratio was lower and RR, Rrs, and LCI were higher in CDH patients than in HI. At T2 Vt, Crs, and FRC remained normal in CDH patients as well as RR that, at this time was not different between CDH and healthy infants; tPTEF/te remained below and Rrs and LCI remained above normal ranges, indicating a persistent impairment in lower airways patency.

CONCLUSIONS

Lung function in infants with severe CDH is characterized by a persistent impairment in airways patency and significant inhomogeneity of ventilation, suggesting a peripheral bronchial obstruction even if the other lung function tests are within normal ranges.

Lung tissue mechanics predict lung hypoplasia in a rabbit model for congenital diaphragmatic hernia

Several animal models have been proposed to study the pathophysiology of congenital diaphragmatic hernia (CDH). Surgical induction of CDH in fetal rabbits during the pseudoglandular phase has been shown to induce severe pulmonary hypoplasia, but functional studies in this model are scarce. We aimed to measure neonatal pulmonary impedance and related it to the severity of lung hypoplasia. CDH was surgically created in rabbits at 23 days of gestation. Following cesarean delivery at term (31 days) pups were subjected to measurement of total lung capacity (TLC), lung to body weight ratio (LBWR) and lung impedance by forced oscillation technique (FOT). Airway resistance (R(aw)), tissue elastance (H(L)), tissue damping (G(L)), and hysteresivity (eta) (G(L)/H(L)) were calculated from impedance data. Twelve CDH fetuses and 15 controls were available for final analysis. LBWR and TLC were significantly lower in the CDH group compared to gestational and age matched controls (P<0.001). R(aw), H(L), and G(L) were significantly increased in CCDH fetuses. eta and H(L) best reflected lung hypoplasia (LBWR) (r(2) = 0.42 and 0.43; P=0.001), indicating a dominant contribution of lung tissue mechanics to CDH-induced lung hypoplasia. We successfully introduced lung impedance measurement by FOT in neonatal rabbits. Following surgical induction of CDH in the pseudoglandular phase, they have, next to morphological evidence of pulmonary hypoplasia, changes in lung mechanics. Our results for lung tissue mechanics support the concept of delayed pulmonary tissue modeling. We propose to employ functional studies in future experiments when evaluating prenatal interventions aimed at reversing pulmonary hypoplasia.

Stephen L. Gans Distinguished Overseas Lecture. The neural crest in pediatric surgery

AIM

This review highlights the relevance of the neural crest (NC) as a developmental control mechanism involved in several pediatric surgical conditions and the investigative interest of following some of its known signaling pathways.

METHODS

The participation of the NC in facial clefts, ear defects, branchial fistulae and cysts, heart outflow tract and aortic arch anomalies, pigmentary disorders, abnormal enteric innervation, neural tumors, hemangiomas, and vascular anomalies is briefly reviewed. Then, the literature on clinical and experimental esophageal atresia-tracheoesophageal fistula (EA-TEF) and congenital diaphragmatic hernia (CDH) is reviewed for the presence of associated NC defects. Finally, some of the molecular signaling pathways involved in both conditions (sonic hedgehog, Hox genes, and retinoids) are summarized.

RESULTS

The association of facial, cardiovascular, thymic, parathyroid, and C-cell defects together with anomalies of extrinsic and intrinsic esophageal innervation in babies and/or animals with both EA-TEF and CDH strongly supports the hypothesis that NC is involved in the pathogenesis of these malformative clusters. On the other hand, both EA-TEF and CDH are observed in mice mutant for genes involved in the previously mentioned signaling pathways.

CONCLUSIONS

The investigation of NC-related molecular pathogenic pathways involved in malformative associations like EA-TEF and CDH that are induced by chromosomal anomalies, chemical teratogens, and engineered mutations is a promising way of clarifying why and how some pediatric surgical conditions occur. Pediatric surgeons should be actively involved in these investigations.

Fetal Tracheal Occlusion for the Treatment of Congenital Diaphragmatic Hernia

BACKGROUND

Congenital diaphragmatic hernia (CDH) continues to be associated with significant mortality and morbidity rates despite advances in neonatal care. Fetal intervention for CDH has been studied for 25 years. After initial difficulties encountered with open fetal repair, attention has turned to tracheal occlusion (TO) as a method to correct pulmonary hypoplasia before birth. This article reviews our contribution to this field of research and outlines the current status of this treatment modality.

MATERIALS AND METHODS

Using the fetal lamb model, we have studied the effects of fetal TO on tracheal fluid pressure, lung growth and type II pneumocyte maturation, and surfactant production. We developed a minimally invasive and reversible technique of TO, using a detachable balloon placed using single-port tracheoscopy. We examined differential lung growth, structural maturation, pulmonary artery remodeling, and lung function during an 8-h resuscitation period in lambs, comparing normal controls, lambs with a surgically created CDH, those with CDH+TO, and those with CDH+TO and release of TO 1 week before delivery. We also studied the potential benefits of maternal betamethasone administration and the administration of surfactant at birth. Using a neonatal piglet model, we examined the effect of postnatal pulmonary distension with perfluorocarbon on lung growth. More recently, we turned to the rat nitrofen-induced CDH model to study the effects of TO on bronchial branching and some molecular markers of lung growth (Shh and LGL1).

CONCLUSIONS

Fetal TO is being used to treat human CDH, but its application remains limited by the absence of reliable and widely reproducible prenatal prognostic criteria. A better understanding of the molecular events guiding the lung growth seen with TO may help to refine its use in humans.

Congenital hernias of the diaphragm in children

BACKGROUND

Congenital diaphragmatic hernia (CDH) is a major congenital malformation. Different types have been described. Bochdalek hernia (BH) remains most prevalent with high mortality rates. Other variants are less common and carry good prognosis. Although, the diagnosis can be made antenatally, the presentation may be delayed. There is paucity of national literature on CDHs. We present our experience with these challenging paediatric malformations.

METHODS

Medical records of 18 patients (< or =14 years) treated by the group of authors between October 1998 and April 2002 were retrospectively reviewed and demographic data, clinical presentation, morbidity and outcome were studied.

RESULTS

There were 13 (72%) children with Bochdalek hernia, 2 (11%) with eventration of the diaphragm, 2 (11%) with hiatus hernia and 1(6%) with a Morgagni hernia. The lesions were more common in girls and all the defects were left sided. The average age at the time of presentation of BH was 23 hours (2 to 72 hours) commonly presenting with cyanosis and respiratory distress. Associated anomalies were documented in 10 (77%) cases; six had multiple malformations and four died before surgery. In other types of CDHs, the mean age at presentation was 39 (18-60) months and they mostly presented with recurrent respiratory tract infections and/or mild gastrointestinal symptoms. Diagnosis was made on history, physical examination, plain x-ray chest, and gastrointestinal contrast study, when required. 14 (78%) children were operated and a sac was present in 5. Post-operative complications occurred in 5 (55%) patients with Bochdalek hernia, which were managed conservatively. The overall survival rate was 67% (n=12).

CONCLUSION

The different types of CDHs presented from neonatal age to later childhood with distinct symptoms. Surgery was safe and effective. Higher morbidity and mortality was observed in newborns with Bochdalek hernia.

Pulmonary function and exercise testing in adult survivors of congenital diaphragmatic hernia

Congenital diaphragmatic hernia (CDH) is accompanied by pulmonary hypoplasia and structural abnormalities of the pulmonary vascular bed. It is unknown whether pulmonary function, exercise capacity, and gas exchange during exercise are impaired in adult CDH survivors. The objective of this study was to assess the long-term pulmonary function, exercise capacity, and gas exchange during exercise and relate these findings with quality of life. Of the 23 patients eligible for this study, 12 adult CDH survivors (mean age, 24.3 +/- 4.1 years) with high-risk CDH agreed to participate. Pulmonary function tests, diffusion capacity, and a cardiopulmonary exercise test (CPET) were performed. The FEV1 (mean z-score +/- SD; -1.30 +/- 1.37), FEF25-75% (-1.49 +/- 1.14), and the KCO (-1.03 +/- 1.24) were found to be lower in CDH survivors. The RV/TLC ratio (28.2% +/- 5.0%) was found to be higher. Despite these abnormalities, percent predicted work load (102% +/- 17.2%) and percent predicted maximal oxygen uptake (90.8% +/- 18.9%) were normal in most of the patients. The quality of life of CDH survivors, assessed with the SF-36 questionnaire, is comparable to the general population. Comparison of participants to non-participants did not reveal significant differences in clinical characteristics. In this first study assessing pulmonary function in adult survivors of CDH, mild airway obstruction was observed in most of the patients together with a slightly reduced diffusion capacity for CO. Exercise capacity and gas exchange parameters were normal in this group, indicating that patients do not have a physical impairment, as reflected by a normal quality of life of CDH patients.

Kidney development in the nitrofen-induced pulmonary hypoplasia and congenital diaphragmatic hernia in rats

BACKGROUND/PURPOSE

The relationship of the developing lung and kidney is not completely understood. Renal enlargement has been reported in association with pulmonary hypoplasia in congenital diaphragmatic hernia (CDH). Recent studies suggest that retinoids may be involved in the pathogenesis of CDH. The aims of this study were to investigate the effects of pulmonary hypoplasia on renal development and to evaluate retinoids status of kidneys in the nitrofen model of CDH.

METHODS

Pregnant rats were exposed to either olive oil or 100 mg of nitrofen on day 9.5 of gestation. Fetuses were recovered at term and divided into 3 groups: 1, control (n = 69); 2, nitrofen without CDH (n = 25); and 3, nitrofen with CDH (n = 40). Kidneys were dissected, weighed, and processed for biochemical measurements of DNA, proteins, total retinol content, and for immunohistochemical staining of proliferating cells.

RESULTS

Kidneys were smaller in nitrofen-exposed animals vs control animals (group 3, 0.65 +/- 0.08; group 2, 0.62 +/- 0.09 vs group 1, 0.73 +/- 0.09% of body weight, P < .001), and there were no differences between right and left kidney weight in all the 3 groups. Regression of total kidney weight on body weight showed a linear direct correlation between them in all the groups. Total amount of DNA was significantly reduced in nitrofen-exposed animals vs controls (group 3, 80.58 +/- 35.65; group 2, 64.71 +/- 20.28 vs group 1, 110.34 +/- 42.15 microg, P < .01), but the DNA concentration remained the same in the 3 groups (group 3, 3.59 +/- 1.26; group 2, 3.06 +/- 1.19; group 1, 3.43 +/- 1.05 microg DNA/mg kidney). Total protein content (group 3, 1145.59 +/- 500.36; group 2, 993.2 +/- 276.62; group 1, 1287.48 +/- 312.52 microg), protein concentration (group 3, 49.76 +/- 11.12; group 2, 43.95 +/- 6.79; group 1, 47.38 +/- 6.93 microg protein/mg kidney), and protein-to-DNA ratio (group 3, 15.12 +/- 5.98; group 2, 16.22 +/- 6.85; group I, 16.16 +/- 7.02 microg/microg) were similar in all groups. Retinol concentration was significantly reduced in both nitrofen-exposed groups compared with the control group (group 3, 1.35 +/- 0.24; group 2, 1.28 +/- 0.11; group 1, 2.53+/-0.61 microg retinol/g kidney). Proliferation index was similar in all 3 groups (group 3, 50.43 +/- 8.81; group 2, 47.96 +/- 6.01; group 1, 47.64 +/- 5.76% of proliferating cells).

CONCLUSIONS

Our data clearly show that renal enlargement in association with pulmonary hypoplasia is not seen in the nitrofen-induced CDH. These results rule out any possible relationship between lung and kidney development. Moreover, kidneys are hypoplastic in both nitrofen-exposed groups and have reduced retinol content, suggesting that a retinoid pathway disruption could be the common mechanism in the pathogenesis of lung and kidney hypoplasia in the nitrofen model of CDH.

Predicting inadequate long-term lung development in children with congenital diaphragmatic hernia: an analysis of longitudinal changes in ventilation and perfusion

PURPOSE

Infants born with congenital diaphragmatic hernia (CDH) demonstrate a wide variability in postnatal catch-up lung growth. The goals of this study were to assess the pulmonary development of children born with CDH using sequential ventilation-perfusion (V/Q) scintigraphy and to identify the perinatal factors that correspond to a progressive V/Q mismatch.

METHODS

The records of 137 patients seen between 1990 and 2005 in a multidisciplinary CDH clinic were reviewed. Changes in the ipsilateral V/Q quotient were compared in 46 patients who had 2 or more studies with the following variables: sex, patch repair, laterality, gestational age, and use of extracorporeal membrane oxygenation. An abnormal V/Q quotient was defined as greater than 1.2 (reference range, 0.8-1.2).

RESULTS

Abnormal V/Q scans were identified in 28 (61%) of the 46 patients at the time of the last V/Q study. Patients who underwent a patch repair had nearly 7 times the risk (P < .001) of developing an ipsilateral V/Q mismatch. The use of extracorporeal membrane oxygenation had a variable effect on the probability of an abnormal V/Q study finding. No other variable was significant.

CONCLUSIONS

Many children with CDH develop significant and progressive V/Q mismatches. Although some perinatal variables appear to be predictive of this phenomenon, they may simply be surrogates for a greater degree of pulmonary hypoplasia present at birth. This subpopulation of CDH survivors is an identifiable group clearly at risk and thus requires long-term follow-up.

Cardiovascular effects of sildenafil in neonates and infants with congenital diaphragmatic hernia and pulmonary hypertension

BACKGROUND

Pulmonary hypertension is a common problem in patients with congenital diaphragmatic hernia (CDH). In a subset of these patients, pulmonary hypertension persists despite optimized ventilatory management and supportive care. Sildenafil, a phosphodiestrase V inhibitor, has been used in the treatment of pulmonary hypertension in adults and children. Cardiovascular effects of sildenafil in patients with CDH and pulmonary hypertension are not known.

OBJECTIVE

To describe the changes in cardiovascular and respiratory parameters in newborn infants with CDH and persistent pulmonary hypertension refractory to inhaled nitric oxide (iNO) during the first 2 weeks of sildenafil administration.

METHODS

Retrospective data analysis of seven patients with CDH (birth weight = 2,573 +/- 1,019 g; gestational age = 35.6 +/- 4.3 weeks) receiving oral sildenafil for pulmonary hypertension refractory to iNO. Findings of serial echocardiograms and data on cardiovascular and respiratory status were assessed.

RESULTS

Right cardiac output increased and left cardiac output tended to increase 1.5-4 h after initiation of sildenafil and the increase was sustained throughout the study. Echocardiographic indices of pulmonary hypertension showed an apparent reduction in abnormally high pulmonary vascular resistance. Systemic blood pressure tended to decrease. Shortening fraction did not change. Ventilatory index and the need for iNO tended to decrease in the five surviving infants.

CONCLUSIONS

These preliminary findings suggest that sildenafil may improve cardiac output by reducing pulmonary hypertension refractory to iNO in patients with CDH.

Role of ATP-dependent potassium channels in pulmonary vascular tone of fetal lambs with congenital diaphragmatic hernia

High mortality in newborn babies with congenital diaphragmatic hernia (CDH) is principally due to persistent pulmonary hypertension. ATP-dependent potassium (K(ATP)) channels might modulate pulmonary vascular tone. We have assessed the effects of Pinacidil, a K(ATP) channel opener, and glibenclamide (GLI), a K(ATP) channel blocker, in near full-term lambs with and without CDH. In vivo, pulmonary hemodynamics were assessed by means of pressure and blood flow catheters. In vitro, we used isolated pulmonary vessels and immunohistochemistry to detect the presence of K(ATP) channels in pulmonary tissue. In vivo, pinacidil (2 mg) significantly reduced pulmonary vascular resistance (PVR) in both controls and CDH animals. GLI (30 mg) significantly increased pulmonary arterial pressure (PAP) and PVR in control animals only. In vitro, pinacidil (10 microM) relaxed, precontracted arteries from lambs with and without CDH. GLI (10(-5) microM) did not raise the basal tone of vessels. We conclude that activation of K(ATP) channels could be of interest to reduce pulmonary vascular tone in fetal lambs with CDH, a condition often associated with persistent pulmonary hypertension of the newborn.

Lung function in infants after repair of congenital diaphragmatic hernia

BACKGROUND/PURPOSE

Congenital diaphragmatic hernia (CDH) is initially characterized by severe restrictive lung defect and low lung compliance, but survivors have relatively few abnormalities later in life. We studied the changes in lung growth and function in infants after the repair of CDH.

METHODS

Retrospective analysis of pulmonary function tests was performed during the first 24 months of life in 56 infants (33 male and 23 female) after repair of CDH. Lung function (functional residual capacity [FRC], respiratory system compliance [C(rs)] and resistance [R(rs)], and maximum expiratory flow rate at FRC [V'(maxFRC)]) were compared among 4 different ages (0-3, 4-6, 7-12, and 13-24 months).

RESULTS

All indices of lung function (mean +/- SD of z scores) were abnormal during the first 6 months of life but were almost normalized by 24 months (P < .0001): FRC, from -0.84 +/- 0.5 to 3.26 +/- 2.07; C(rs), from -0.87 +/- 0.4 to 1.84 +/- 1.75; R(rs), from 2.85 +/- 2.71 to -0.23 +/- 2.03, and V'(maxFRC), from -1.63 +/- 0.4 to -0.09 +/- 0.94. There was significant correlation (P < .001) between lung function and increase in age, height, and especially weight.

CONCLUSIONS

Lung growth and function gradually normalize between 6 and 24 months of life after repair of CDH.

Resting and exercise cardiorespiratory function in survivors of congenital diaphragmatic hernia

Our objective was to study exercise capacity and cardiorespiratory response to exertion in survivors of congenital diaphragmatic hernia (CDH). This was a cross-sectional cohort study of 23 CDH survivors, aged 10-16 years, and 23 gender- and age-matched controls. Exercise testing was performed on a cycle ergometer, with cardiac output measurements made using exponential CO2 rebreathing. Pretest cardiorespiratory assessment was done by echocardiography and pulmonary function testing. Statistical analysis was performed using Student's t-test, regression analysis, and longitudinal model computing with spatial covariance structure. No echocardiographic evidence for pulmonary hypertension was found at rest (right ventricular systolic pressures, 27 +/- 6 mmHg). Mean pulmonary artery diameter on the side of the CDH was significantly smaller than contralaterally, but was within normal range (z-score, 0 +/- 1.1 vs. 1.2 +/- 1.6, P < 0.01). Exercise capacity was mildly reduced in CDH compared to controls and predictive data (maximum workload, 77% +/- 12% vs. 91% +/- 16% of predicted, P < 0.01). Cardiorespiratory response to exertion was not significantly different between groups. In conclusion, most adolescent CDH survivors have nearly normal exercise capacity and cardiorespiratory response to exertion. This study may prove useful in comparisons with future cohorts comprising more severely affected individuals now surviving due to improved neonatal care.

Airway smooth muscle dysfunction precedes teratogenic congenital diaphragmatic hernia and may contribute to hypoplastic lung morphogenesis

Fetal intervention aims to improve lung growth and survival in congenital diaphragmatic hernia (CDH). Airway smooth muscle (ASM) is important in lung development: ASM progenitors produce a key growth factor for lung morphogenesis (fibroblast growth factor 10); ASM contractility is also coupled to growth. ASM hyperreactivity occurs in postnatal CDH and may exacerbate barotrauma via impaired lung compliance. We hypothesize that ASM hyperreactivity and its sequelae are based on an early developmental lesion of ASM activity in hypoplastic lung. Sprague-Dawley rats were fed 100 mg nitrofen on Day 9.5 of pregnancy to induce lung hypoplasia in offspring (controls had vehicle alone). Normal and hypoplastic lung primordia were cultured from Day 13.5 of gestation at 37 degrees C in 5% CO(2) and loaded at 54 or 78 h with Ca(2+)-sensitive indicators: Fluo-4 for confocal imaging and Indo-1 or Fura-2 for photometric measurements of [Ca(2+)](i). Hypoplastic lung features spontaneous propagating ASM Ca(2+) transients with reduced frequency, increased amplitude, and significantly prolonged plateau duration, relative to control lung. Nonetheless, hypoplastic lung exhibits normal requirement for extracellular calcium entry and intracellular calcium release in initiation and regulation of ASM Ca(2+) waves. Early ASM dysfunction in lung hypoplasia is apparent as specific anomalies of Ca(2+) transients that indicate a problem with plasmalemmal ion channels/action potential generation. Elucidation of such an ASM lesion may allow pharmacologic amelioration not only of ASM hyperreactivity and its sequelae, but also of hypoplastic lung growth itself.

Case report: Morgagni hernia

The case reported here is a 32-year-old man with a sudden onset of chest pain and an acute deterioration of lung function. An incarcerated Morgagni hernia was diagnosed with a computer tomographic CT scan, and repaired electively via a midline laparotomy. Morgagni hernia is a rare type of congenital diaphragmatic hernia, which may not be symptomatic until adulthood when the patient presents with acute symptoms or incarceration.

Sex and congenital diaphragmatic hernia

BACKGROUND AND PURPOSE

Human studies note sex reversal syndromes and sex difference(s) in the incidence of congenital diaphragmatic hernia (CDH). Epidemiology surveys record a higher incidence of CDH in females, whilst other reports cite a higher frequency in males. Nitrofen, a teratogen, produces experimental CDH. This agent is speculated to interfere with retinoid acid-steroid signalling pathways and may also be linked with sexual differentiation. This study was designed therefore to test the hypothesis that nitrofen may influence sexual phenotype and frequency of CDH.

METHODS

Time mated Sprague Dawley rats were dosed with nitrofen at day 9.5 to generate predominantly left sided CDH. Fetuses were delivered by caesarean section on days 20 or 21 of gestation (term=day 22). External genitalia were examined to define external genital phenotype. The abdominal cavity was opened and the genito-urinary system carefully examined. The internal genital organs were assigned a phenotype and findings correlated with external appearances. The diaphragm of each fetus was studied for the absence or presence of CDH and the laterality of defect recorded. Controls (non nitrofen fed) were used for all comparative analysis.

RESULTS

Control (n=600) and nitrofen exposed offspring (n=504) had equal frequencies of males and females. CDH occurred with similar incidence in male and female nitrofen treated pups. In all nitrofen exposed fetuses and normal controls, internal and external genitalia concorded without evidence of significant genital tract malformations or intersex states.

CONCLUSIONS

Prenatal nitrofen exposure is not associated with significant gender differences (or prenatal loss) in the risk of CDH. Genital tract malformations do not appear to accompany CDH in the nitrofen model.

Retinoic acid rescues lung hypoplasia in nitrofen-induced hypoplastic foetal rat lung explants

There is increasing evidence to suggest that the retinoid pathway is involved in the pathogenesis of congenital diaphragmatic hernia (CDH). We hypothesised that retinoids are involved in the pathogenesis of associated pulmonary hypoplasia in CDH and therefore designed this study to investigate the effects of retinoid acid on nitrofen-induced hypoplastic lungs. Pregnant rats were exposed to either olive oil or 100 mg nitrofen on day 9.5 of gestation. Foetal lungs were harvested on embryonic day 13.5 and were cultured for 96 h with or without exogenous retinoic acid (RA) (1 muM) added daily to the culture medium. Lungs were divided into four study groups: control (n=31); control + RA (n=19); nitrofen (n=19); and nitrofen + RA (n=12). Lung growth was assessed in each group by measuring branching morphogenesis, total DNA content and the proportion of proliferating cells stained by immunohistochemistry. One-way ANOVA test was used for statistical analysis. Retinoic acid significantly increased the growth of nitrofen-induced hypoplastic lungs, whilst growth of control lungs did not change. The number of lung buds and lung area of nitrofen-exposed hypoplastic lungs after 96 h of culture significantly increased after the addition of RA compared to the non-treated hypoplastic lungs (25.75+/-6.47 vs 15.11+/-3.29 and 0.98+/-0.18 mm(2) vs 0.65+/-0.13 mm(2), respectively; P<0.0001). Lung perimeter was also higher when RA was added to hypoplastic lungs compared to the non-treated ones, although it did not reach significance (12.51+/-2.53 mm vs 11.19+/-2.56 mm; P=0.17). Conversely, the addition of RA to control lungs did not affect the number of lung buds, lung area or lung perimeter after 96 h in culture compared to the non-treated ones (31.28+/-4.66 vs 31.81+/-6.67; 1.29+/-0.18(2) vs 1.29+/-0.23 mm(2) and 18.47+/-3.47 mm vs 17.89+/-2.94 mm, respectively; P=NS). Retinoic acid also increased the total DNA content and the proportion of proliferating cells in hypoplastic lungs compared to the non-treated ones (2.59+/-0.58 mug vs 1.96+/-0.31 mug and 57.89+/-9.46% vs 36.76+/-8.15%, respectively; P<0.001). The addition of RA did not affect either total DNA content or the proportion of proliferating cells in control lungs compared to the non-treated ones (4.04+/-0.64 mug vs 3.79+/-0.85 mug and 58.67+/-11.23% vs 56.03+/-10.36%, respectively; P=NS). This study demonstrates for the first time that RA rescues lung hypoplasia in nitrofen-induced hypoplastic lungs. These results suggest that retinoid pathway may be involved in the pathogenesis of associated pulmonary hypoplasia in CDH.

Mid- and long-term effects on pulmonary perfusion, anatomy and diaphragmatic motility in survivors of congenital diaphragmatic hernia

The aim of the present study was to evaluate the pulmonary sequelae and diaphragmatic motility in infant, adolescent and adult patients (pts) who had undergone the repair of a congenital diaphragmatic hernia. Thirty-one (81.5%) out of 38 survivors after left side CDH repair, without using a patch, were followed-up. They were subdivided in two groups. Group A (mid-term follow-up): 12 pts (39%) (5 males, 7 females) with a mean age of 4.5 years; Group B (long-term follow-up): 19 pts (61%) (9 males, 10 females) with a mean age of 21.0 years. All pts underwent physical examination, chest X-ray, diaphragmatic ultrasonographic (US) examination, pulmonary perfusion scintigraphy. Patients of the group B were also submitted to spirometry. All pts had a normal life-style and no one complained of respiratory symptoms. The chest X-ray revealed pathologic findings in 12 pts (39%). 8 pts (26%) showed chest wall alterations. The profile of the left diaphragmatic dome appeared irregular in 9 pts (29%). In all pts M-mode sonography disclosed a reduced diaphragmatic motility on the treated side. The mean pulmonary perfusion scintigraphy value on the affected side was 39.2+/-0.7%. The spirometric study showed normal values. We noted that the lung perfusion significantly and rapidly improved after CDH repair even the apparently hypoplastic and small lungs, the diaphragm maintained a good contractility during forced respiration.

Nitrovasodilator responses in pulmonary arterioles from rats with nitrofen-induced congenital diaphragmatic hernia

BACKGROUND/PURPOSE

Many infants with congenital diaphragmatic hernias (CDHs) experience persistent pulmonary hypertension that is refractory to treatment with inhaled nitric oxide (NO). We have examined the responses of isolated pulmonary arterioles from prenatal and postnatal rats with and without nitrofen (2,4-dichlorophenyl-p-nitrophenyl ether)-induced CDH to a variety of activators of the NO-cyclic guanosine monophosphate (cGMP) pathway.

METHODS

Right-sided CDH was induced in fetal rats by feeding nitrofen to pregnant rats on day 12 of gestation. Control rats were fed olive oil (vehicle). Third-generation pulmonary arterioles were isolated from the right lung of prenatal rats at term and from newborn rats within 8 hours after birth. Responses to increasing concentrations of sodium nitroprusside (SNP), atrial natriuretic peptide, or 8-bromo-cGMP were measured in pulmonary arterioles from control rats and from rats with nitrofen-induced CDH. Postnatal responses to 8-bromo-cGMP were also recorded in the presence of zaprinast, a type V phosphodiesterase inhibitor.

RESULTS

Pulmonary arterioles from prenatal rats did not dilate in response to SNP, atrial natriuretic peptide, or 8-bromo-cGMP. Vasodilatory responses of postnatal pulmonary arterioles from control rats to SNP and 8-bromo-cGMP were significantly greater than for arterioles from rats with CDH. Zaprinast pretreatment resulted in similar responses for postnatal CDH and control arterioles to 8-bromo-cGMP.

CONCLUSIONS

Postnatal pulmonary arterioles from CDH rats exhibit altered nitrovasodilator responsiveness, which may be due to rapid degradation of cGMP.

Neonatal lung remodeling: structural, inflammatory, and ventilator-induced injury

The developing lung is subject to events, both prenatal and postnatal, that alter the normal developmental process. The degree of insult or injury affects how the lung functions at birth and then responds to the insult throughout childhood. In this article, only 3 of the influences are examined: structural, inflammatory, and mechanical. It is recognized that there is a plethora of other factors that influence lung remodeling.

Lung development is not necessary for diaphragm development in mice

BACKGROUND/PURPOSE

Congenital diaphragmatic hernia affects approximately 1 in every 2000 live births. The etiology of these diaphragmatic defects is unknown. Using mice with a targeted deletion of fibroblast growth factor 10 (FGF10), which display a complete lack of lung tissue, we have examined the relationship between lung hypoplasia and diaphragmatic development.

METHODS

The diaphragms of FGF10 null mice were examined at 2 embryonic time-points and compared with their heterozygous and wild-type littermates.

RESULTS

FGF10 null mice had phenotypically normal diaphragms when compared with wild-type littermates at both time-points studied.

CONCLUSION

Normal diaphragm development appears to occur independent of lung development in mice.

Congenital diaphragmatic hernia: searching for answers

BACKGROUND

Pulmonary hypoplasia and hypertension are the primary causes of morbidity and mortality in infants with congenital diaphragmatic hernia (CDH). At present, the origin of CDH and the causes of pulmonary hypoplasia and hypertension are unknown.

DATA SOURCES

This article reviews the available published data regarding the origin of CDH and the pathogenesis of the associated pulmonary hypertension and hypoplasia. These investigations have employed human tissues as well as two types of CDH animal models.

CONCLUSIONS

Investigations performed to date have not yet provided definitive answers regarding the pathogenesis of CDH. However, they have yielded many new and exciting discoveries and several opportunities for intervention. Ongoing research should open new possibilities to improve the outcome for these unfortunate babies with CDH.

The co-occurrence of congenital diaphragmatic hernia, esophageal atresia/tracheoesophageal fistula, and lung hypoplasia

BACKGROUND

Two severe birth defects, congenital diaphragmatic hernia (CDH) and esophageal atresia (EA) with or without tracheoesophageal fistula (TEF), have traditionally been analyzed separately in epidemiological studies. Lung hypoplasia (LH), part of the CDH spectrum, is not usually associated with EA/TEF, yet both are foregut malformations.

METHODS

We conducted an epidemiological study of two combinations of the defects in the population of 3,318,966 live births and stillbirths monitored from 1983 to 1996 by the California Birth Defects Monitoring Program (CBDMP).

RESULTS

A total of 433 cases had a Bochdalek type CDH/LH (0.13 per 1000 births), 893 had EA/TEF (0.27 per 1000 births), and 646 had LH (0.19 per 1000 births). Among them, 18 cases had CDH/LH with EA/TEF (0.005 per 1000 births), and 53 had EA/TEF and LH (0.02 per 1000 births); both prevalences are significantly higher than expected. Sixteen of 17 cases of CDH/LH with EA/TEF, and 34 of 40 cases of EA/TEF with LH were stillborn or died; 72% and 74%, respectively, had an autopsy. The male to female sex ratios were 1.43 and 1.13, respectively. In both groups, infants had similar proportions of additional severe defects, except for genitourinary and anal defects and syndromes/associations, which were more prevalent in the EA/TEF with LH group. We reviewed human studies and experimental animal models for factors reported to cause any combination of the defects.

CONCLUSIONS

Several genetic and environmental factors could affect the significant co-occurrence of the defects. Future studies should include storage of patients' biological materials for DNA analysis, karyotyping, and environmental exposure evaluation.

Surfactant metabolism in the neonate

With the use of stable isotope-labeled intravenous precursors for surfactant phosphatidylcholine (PC) synthesis, it has been shown that the de novo synthesis rates in preterm infants with respiratory distress syndrome (RDS) are very low as are turnover rates. This is consistent with animal data. Surfactant therapy does not inhibit endogenous surfactant synthesis, and prenatal corticosteroids stimulate it. With the use of stable isotope-labeled PC given endotracheally, surfactant pool size was estimated. It turned out to be low in RDS, as expected. Similar studies were performed in term neonates with severe lung diseases. In general, patients with lung injury show a lower surfactant synthesis. The controversy around surfactant in congenital diaphragmatic hernia (CDH) persists: studies on CDH with and without extracorporeal membrane oxygenation yielded different results. In severe meconium aspiration syndrome surfactant synthesis was found to be decreased but surfactant pool size was maintained. It is possible and safe to study surfactant metabolism in human neonates with the use of stable isotopes. This can help in answering clinical questions and has the potential to bring new in vitro and animal findings about surfactant metabolism to the patient.

Congenital diaphragmatic hernia: intensive care unit or operating room?

Despite improvements in prenatal diagnosis and neonatal intensive care, the Congenital Diaphragmatic Hernia (CDH) Registry still records a 64% survival rate. Many reports demonstrate, however, that approximately 80% of CDH patients with no other malformations may survive if managed with permissive hypercapnia, gentle ventilation, high-frequency oscillatory ventilation (HFOV), surfactant, inhaled nitric oxide (iNO) and extracorporeal membrane oxygenation (ECMO), and delayed surgical repair. We wished to define the evolving outcome of CDH newborns using a protocol approach to management, which includes surgery in the neonatal intensive care unit (NICU) or operating room (OR). From January 1996, data were collected prospectively on 42 consecutive live-born infants with CDH. Newborns symptomatic at birth were sedated and paralyzed in the delivery room, and treated with elective HFOV, iNO, surfactant, and ECMO as necessary, delaying surgical repair until their clinical conditions were stable. Once the CDH newborn was stabilized, a trial on conventional ventilation was started at least 24 hours before surgery; however, if the patient was unstable, therapy was switched back to HFOV and surgery was performed in the NICU. Demographic and clinical parameters were compared between CDH newborns who underwent surgery in the NICU and in the OR. The two groups were comparable in terms of clinical characteristics and baseline ventilatory and blood gas values. Mean age at surgery was 3 +/- 2 days. After surgery, the NICU group had more infectious complications. However, the survival rate of uncomplicated CDH was 78% and a low rate of chronic lung disease was reported. A prolonged phase of presurgery stabilization is proposed and strict control of infection is recommended for the CDH newborns who might benefit from an exclusive HFOV and NICU surgery.

The genetics of congenital diaphragmatic hernia

Congenital diaphragmatic hernia (CDH) is a common birth defect with a high mortality and morbidity. A clear understanding of the pathogenesis of CDH is critical for determining prognosis and planning treatment, but to date, information on the genetic etiology of both nonsyndromic and syndromic CDH is limited. This paper summarizes the current knowledge concerning the genes, syndromes, and chromosome aberrations associated with CDH in humans and in animal model systems. Mutations in several different genes have been described in syndromic CDH, but there is only one mutation that has been reported in non-syndromic CDH to date. However, animal models suggest that genes involved in cell migration, myogenesis, and connective tissue formation are critical to normal diaphragm formation, and these data provide a starting point for the search for other genes involved in the pathogenesis of CDH.

Nasopharyngeal teratoma and diaphragmatic hernia: a non random association?

We describe a female affected by diaphragmatic hernia and nasopharyngeal teratoma. The case is compared with one already reported and possible diagnoses discussed. These cases appear to represent a new syndrome.