Fisiopatología de la hernia diafragmática congénita en el recién nacido / Pathophysiology of congenital diaphramatic hernia in the newborn

La hernia diafragmática congénita es una discontinuidad del diafragma con herniación de los órganos abdominales a la cavidad torácica, actualmente se postula una hipótesis dual para su origen. Su fisiopatología está determinada por la hipoplasia pulmonar, la hipertensión pulmonar y la disfunción ventricular, entender estos elementos es necesario para un adecuado manejo y la mejoría del pronóstico.

Congenital diaphragmatic hernia is a discontinuity of the diaphragm with herniation of the abdominal organs into the thoracic cavity, currently a dual hypothesis for its origin is postulated. Its pathophysiology is determined by pulmonary hypoplasia, pulmonary hypertension and ventricular dysfunction, understanding these elements is necessary for adequate management and improve prognosis.

Survival outcome in severe left-sided congenital diaphragmatic hernia with and without fetal endoscopic tracheal occlusion in a country with suboptimal neonatal management.

OBJECTIVE: To evaluate the impact of fetal endoscopic tracheal occlusion (FETO) on improving survival of fetuses with severe left-sided congenital diaphragmatic hernia (CDH), as compared with contemporaneous cases managed expectantly during pregnancy, in a country with suboptimal neonatal management. METHODS: In this prospective cohort study, consecutive fetuses with isolated left-sided CDH, normal karyotype and severe pulmonary hypoplasia (defined as liver herniation and observed/expected lung-to-head circumference ratio below 26%) were selected for FETO at less than 32 weeks of gestation in a single tertiary referral center in Queretaro, Mexico. Postnatal outcome (survival up to 28 days after birth) was compared between fetuses treated with FETO and contemporaneous cases with similar lung size managed expectantly during pregnancy. RESULTS: Twenty-five fetuses with isolated severe left-sided CDH treated with FETO were matched individually with 25 cases managed expectantly during pregnancy. Endotracheal placement of the balloon was performed successfully on the first attempt in all cases. The median gestational age (GA) at balloon placement was 29.1 (range, 25.6-31.8) weeks and 34.1 (range, 30.0-36.1) weeks at balloon removal. There were no technical problems with the introduction or removal of the balloon in any cases. The median GA at delivery was significantly lower in the group treated with FETO than in those managed expectantly (35.3 vs 37.7 weeks; P = 0.04). The survival rate was significantly higher in the group treated with FETO than in those without fetal intervention (32% vs 0%; P < 0.001). CONCLUSION: In settings with suboptimal neonatal management, FETO was associated with improved neonatal survival in fetuses with isolated left-sided CDH and severe pulmonary hypoplasia. Copyright © 2020 ISUOG. Published by John Wiley & Sons Ltd.

Resultado de supervivencia en una hernia diafragmática congénita grave del lado izquierdo, con y sin oclusión traqueal endoscópica fetal en un país con un tratamiento neonatal subóptimo OBJETIVO: Evaluar el impacto de la oclusión traqueal endoscópica fetal (OTEF) en la mejora de la supervivencia de los fetos con hernia diafragmática congénita (HDC) grave del lado izquierdo, en comparación con los casos actuales tratados como embarazo gestante, en un país con un tratamiento neonatal subóptimo. MÉTODOS: En este estudio prospectivo de cohortes, se seleccionaron fetos consecutivos con HDC aislada del lado izquierdo, cariotipo normal e hipoplasia pulmonar grave (definida como hernia hepática y una proporción observada/esperada de la circunferencia pulmonar-cabeza inferior al 26%) para una OTEF antes de las 32 semanas de gestación, en un único centro de medicina especializada terciaria en Querétaro (México). El resultado postnatal (supervivencia hasta los 28 días después del nacimiento) se comparó entre fetos tratados con OTEF y los casos contemporáneos con tamaño pulmonar similar, tratados como embarazo gestante. RESULTADOS: Veinticinco fetos con HDC grave aislada del lado izquierdo que habían sido tratados con OTEF fueron emparejados individualmente con 25 casos tratados como embarazo gestante. La colocación endotraqueal del globo se realizó con éxito en el primer intento en todos los casos. La mediana de la edad gestacional (EG) en el momento de la colocación del globo fue de 29,1 (rango, 25,6-31,8) semanas y 34,1 (rango, 30,0-36,1) semanas cuando se retiró el globo. En ningún caso hubo problemas técnicos con la introducción o la retirada del globo. La mediana de la EG en el momento del parto fue significativamente menor en el grupo tratado con OTEF que en el grupo tratado como gestante (35,3 vs 37,7 semanas; P=0,04). La tasa de supervivencia fue significativamente más alta en el grupo tratado con OTEF que en los casos sin intervención fetal (32% vs 0%; P<0,001). CONCLUSIÓN: En los entornos con un tratamiento neonatal subóptimo, la OTEF se asoció con una mejora de la supervivencia neonatal en los fetos con HDC aislada del lado izquierdo y con hipoplasia pulmonar grave. Copyright © 2020 ISUOG. Published by John Wiley & Sons Ltd.

Longitudinal changes in lung size and intrapulmonary-artery Doppler during the second half of pregnancy in fetuses with congenital diaphragmatic hernia.

OBJECTIVES: The objectives of the study are to evaluate longitudinal changes in lung size and intrapulmonary-artery (IPa) Doppler in fetuses with congenital diaphragmatic hernia (CDH) and assess their contribution in predicting neonatal survival. METHODS: The observed/expected lung-to-head ratio (O/E-LHR) and IPa-pulsatility index (PI) and peak early diastolic reversed flow (PEDRF) were evaluated in a cohort of left-sided CDH fetuses managed expectantly during pregnancy. Longitudinal changes were analyzed by multilevel analysis, and their value to predict survival using the multiple logistic regression and decision-tree analysis was assessed. RESULTS: A total of 232 scans were performed on 69 CDH fetuses. The O/E-LHR values remained unchanged during fetal monitoring, whereas IPa-PI and PEDRF showed a progressive increase throughout follow-up, becoming abnormal on average at 30 weeks of gestation. Absent/reversed end-diastolic velocity (EDV) in the IPa was observed in 20.3%. O/E-LHR and IPa Doppler indices were significantly associated with probability of survival (O/E-LHR ≥ 26%, odds ratio [OR] 19.0; IPa-PI <+2.0 z score, OR 3.0; and positive EDV, OR 7.4). All cases with IPa-reversed EDV died after birth. CONCLUSION: While lung size remains stable during pregnancy, CDH fetuses show progressive deterioration in intrapulmonary blood flow. IPa Doppler evaluation may aid in predicting survival of CDH fetuses managed expectantly during pregnancy.

Hernia diafragmática congénita / Congenital diaphragmatic hernia

The congenital diaphragmatic hernia (CDH) is a congenital defect of the formation and /or closure of the diaphragm that permits the herniation of abdominal contents into the thorax. It occurs when the diaphragmatic muscle fails to close during the prenatal development, and the contain of the abdomen migrate into the chest through this hole. When the abdominal organs are in the chest, there is limited room for the lungs to grow. This prevents the lungs for developing normally, resulting in pulmonary hypoplasia (or underdeveloped lungs). This can cause reduced blood flow to the lungs and pulmonary hypertension, as well as gastrointestinal reflux, feeding disorders and developmental delays. CDH can occur on the left side, right side or, very rarely, on both sides, and it can be life-threatening. The etiology is usually unknown. The incidence of CDH may be as high as 1 in 2000 to 1 in 5000 newborns alive. The sex relationship male/female is 1:1.8. Because of associated persistent pulmonary hypertension of the newborn and pulmonary hypoplasia, medical therapy in patients with CDH is directed toward optimizing oxygenation while avoiding definitive therapy. No time for repair of CDH is ideal, but it is suggested that the opportunity is 24-48 hours after birth to achieve pulmonary development. The key to survival lies in prompt diagnosis and treatment. Over the past two decades antenatal diagnosis rates have increased the knowledge of the pathophysiology of CDH and has become better understand with advances in clinical care including prenatal surgery, with a reported mortality of almost 35 % in live-born patients and a higher mortality when in utero deaths are conected. All these considerations are described in the article, with special reference to pre and post-natal treatment, complications management, diagnosis and prognosis

Spontaneous prematurity in fetuses with congenital diaphragmatic hernia: a retrospective cohort study about prenatal predictive factors.

BACKGROUND: To evaluate possible predictive factors of spontaneous prematurity in fetuses with congenital diaphragmatic hernia (CDH). METHODS: A retrospective cohort study was performed. Inclusion criteria were presence of CDH; absence of fetoscopy; absence of karyotype abnormality; maximum of one major malformation associated with diaphragmatic hernia; ultrasound monitoring at the Obstetrics Clinic of Clinicas Hospital at the University of São Paulo School of Medicine, from January 2001 to October 2014. The data were obtained through the electronic records and ultrasound system of our fetal medicine service. The following variables were analyzed: maternal age, primiparity, associated maternal diseases, smoking, previous spontaneous preterm birth, fetal malformation associated with hernia, polyhydramnios, fetal growth restriction, presence of intrathoracic liver, invasive procedures performed, side of hernia and observed-to- expected lung to head ratio (o/e LHR). On individual analysis, variables were assessed using the Chi-square test and the Mann-Whitney test. A multiple logistic regression model was applied to select variables independently influencing the prediction of preterm delivery. A ROC curve was constructed with the significant variable, identifying the values with best sensitivity and specificity to be suggested for use in clinical practice. RESULTS: Eighty fetuses were evaluated, of which, 21 (26.25%) were premature. O/e LHR was the only factor associated with prematurity (p = 0.020). The ROC curve showed 93% sensitivity with 48.4% specificity for the cutoff of 40%. CONCLUSION: O/e LHR was the only predictor of prematurity in this sample.

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.

Longitudinal assessment of lung area measurements by two-dimensional ultrasound in fetuses with isolated left-sided congenital diaphragmatic hernia.

OBJECTIVE: To evaluate lung growth in healthy fetuses and those with congenital diaphragmatic hernia (CDH) using two-dimensional (2D) ultrasound. METHODS: Fetal right lung measurements obtained by 2D ultrasound between 19 and 37 weeks' gestation were evaluated longitudinally in 66 healthy fetuses and 52 fetuses with isolated left-sided CDH. Right lung areas were determined by the 'tracing' and 'longest-diameters' methods and, subsequently, lung area-to-head circumference ratios (LHRs) were calculated. Functions fitted to these size parameters with respect to gestational age were evaluated for three sets of group-wise comparisons: (1) healthy vs CDH fetuses; (2) different degrees of severity of CDH; and (3) CDH fetuses that survived vs those that died by 6 months postpartum. RESULTS: There was a significantly slower increase in right lung areas and LHRs with advancing gestational age in CDH fetuses than in healthy individuals (P < 0.05). Compared to those with milder forms of CDH, lung areas and LHRs of fetuses with more severe forms displayed a smaller increase (P < 0.05) and LHRs of fetuses with severe CDH did not increase during pregnancy (P > 0.05). Individuals who died postpartum did not show any increase in LHR (P > 0.05) throughout gestation. CONCLUSIONS: The right lung area and LHR, calculated using either the longest-diameters or tracing method, display reduced growth rates during gestation in cases of isolated left-sided CDH as compared with healthy fetuses. The growth curve characteristics of fetal lung areas and LHRs may be useful for predicting neonatal mortality.

Effect of corticosteroids and lung ventilation in the VEGF and NO pathways in congenital diaphragmatic hernia in rats.

PURPOSE: The use of dexamethasone (Dx) stimulates growth, fetal lung maturation and can improve pulmonary hypertension in congenital diaphragmatic hernia (CDH). Our aim was to evaluate the effect of Dx on the lung after fetal pulmonary ventilation in the CDH rat model. METHODS: Some groups underwent prenatal treatment with dexamethasone (0.4 mg/kg) that was given at 18.5 gestational day (GD). Sprague-Dawley rat fetuses were divided into groups: control (C); ventilated control (CV); control exposed to dexamethasone (CDx); ventilated control exposed to dexamethasone (CVDx); congenital diaphragmatic hernia (CDH), ventilated CDH (CDHV), CDH exposed to dexamethasone (CDHDx) and ventilated CDH exposed to dexamethasone (CDHVDx). At 21.5 GD fetuses were delivered by C-section, weighed and ventilated for 30 min. We analyzed the lung morphometry by Masson's Trichrome stain, and VEGF, VEGFR1, VEGFR2 and NOS3 expression by immunohistochemistry. RESULTS: All fetuses with CDH, with or without prenatal dexamethasone showed lung and body weight lower than control fetuses (p < 0.05). All groups that received dexamethasone showed a decrease in the medial muscular layer of arterioles, the internal diameter of the air spaces (Lma) and length of parenchymal transection/airspace ratio (p < 0.05). In the immunohistochemistry, VEGF decreased more in CDHDV group (p < 0.05). VEGFR1 showed no difference, whereas VEGFR2 decreased significantly in the CDHDV group (p < 0.05). NOS3 increased in the group CDHDV (p < 0.05). CONCLUSION: The use of prenatal dexamethasone added to ventilation alters the VEGF and NO pathways.

VEGF receptor expression decreases during lung development in congenital diaphragmatic hernia induced by nitrofen.

Changes in vascular endothelial growth factor (VEGF) in pulmonary vessels have been described in congenital diaphragmatic hernia (CDH) and may contribute to the development of pulmonary hypoplasia and hypertension; however, how the expression of VEGF receptors changes during fetal lung development in CDH is not understood. The aim of this study was to compare morphological evolution with expression of VEGF receptors, VEGFR1 (Flt-1) and VEGFR2 (Flk-1), in pseudoglandular, canalicular, and saccular stages of lung development in normal rat fetuses and in fetuses with CDH. Pregnant rats were divided into four groups (n=20 fetuses each) of four different gestational days (GD) 18.5, 19.5, 20.5, 21.5: external control (EC), exposed to olive oil (OO), exposed to 100 mg nitrofen, by gavage, without CDH (N-), and exposed to nitrofen with CDH (CDH) on GD 9.5 (term=22 days). The morphological variables studied were: body weight (BW), total lung weight (TLW), left lung weight, TLW/BW ratio, total lung volume, and left lung volume. The histometric variables studied were: left lung parenchymal area density and left lung parenchymal volume. VEGFR1 and VEGFR2 expression were determined by Western blotting. The data were analyzed using analysis of variance with the Tukey-Kramer post hoc test. CDH frequency was 37% (80/216). All the morphological and histometric variables were reduced in the N- and CDH groups compared with the controls, and reductions were more pronounced in the CDH group (P<0.05) and more evident on GD 20.5 and GD 21.5. Similar results were observed for VEGFR1 and VEGFR2 expression. We conclude that N- and CDH fetuses showed primary pulmonary hypoplasia, with a decrease in VEGFR1 and VEGFR2 expression.

VEGF receptor expression decreases during lung development in congenital diaphragmatic hernia induced by nitrofen

Changes in vascular endothelial growth factor (VEGF) in pulmonary vessels have been described in congenital diaphragmatic hernia (CDH) and may contribute to the development of pulmonary hypoplasia and hypertension; however, how the expression of VEGF receptors changes during fetal lung development in CDH is not understood. The aim of this study was to compare morphological evolution with expression of VEGF receptors, VEGFR1 (Flt-1) and VEGFR2 (Flk-1), in pseudoglandular, canalicular, and saccular stages of lung development in normal rat fetuses and in fetuses with CDH. Pregnant rats were divided into four groups (n=20 fetuses each) of four different gestational days (GD) 18.5, 19.5, 20.5, 21.5: external control (EC), exposed to olive oil (OO), exposed to 100 mg nitrofen, by gavage, without CDH (N-), and exposed to nitrofen with CDH (CDH) on GD 9.5 (term=22 days). The morphological variables studied were: body weight (BW), total lung weight (TLW), left lung weight, TLW/BW ratio, total lung volume, and left lung volume. The histometric variables studied were: left lung parenchymal area density and left lung parenchymal volume. VEGFR1 and VEGFR2 expression were determined by Western blotting. The data were analyzed using analysis of variance with the Tukey-Kramer post hoc test. CDH frequency was 37% (80/216). All the morphological and histometric variables were reduced in the N- and CDH groups compared with the controls, and reductions were more pronounced in the CDH group (P<0.05) and more evident on GD 20.5 and GD 21.5. Similar results were observed for VEGFR1 and VEGFR2 expression. We conclude that N- and CDH fetuses showed primary pulmonary hypoplasia, with a decrease in VEGFR1 and VEGFR2 expression.