Abdominal circumference in fetuses with congenital diaphragmatic hernia: correlation with hernia content and pregnancy outcome

Value of liver herniation in prediction of outcome in fetal congenital diaphragmatic hernia: a systematic review and meta-analysis

OBJECTIVES

Intrathoracic liver herniation (ILH) is being used to estimate prognosis and hence guide antenatal interventions in fetal congenital diaphragmatic hernia (CDH). However, the literature regarding its utility in this role is conflicting. This review systematically examines the currently available evidence of ILH use in fetal CDH.

METHODS

MEDLINE and EMBASE databases were searched for the terms ((congenital diaphragmatic hernia) OR CDH) AND liver. Inclusion criteria were human case series of fetuses diagnosed with CDH using either ultrasound or magnetic resonance imaging. Included studies were required to have reported the antenatal liver position and the outcome (survival or not). Case reports, reviews and eventration series were excluded. Studies reporting similar cases from the same center over an overlapping time period were considered duplicates; only the larger of the studies were therefore included. Absolute totals were extracted and sums calculated. Fisher's exact test (FET) was used to compare survival rates in different groups.

RESULTS

The original search retrieved 338 studies. Applying inclusion/exclusion criteria and removing duplicates left 21 case series in 20 studies. Retrieved studies differed in the definitions of liver herniation, survival and treatment modality. In total, there were 407 fetuses in the liver-up (herniated) and 303 in the liver-down (not herniated) groups. Survival rates were 45.4% and 73.9%, respectively. The difference was statistically significant (FET = 56.4, P < 0.005). Sensitivity analysis for cases that had only conventional postnatal treatment was still significant (FET = 52.8, P < 0.005).

CONCLUSIONS

Liver herniation is associated with poorer prognosis in fetal CDH. Grading liver herniation or using it as part of a panel of markers may enhance the value of liver herniation as a prognostic test in fetal CDH.

Tracheal occlusion for fetal congenital diaphragmatic hernia: the US experience

Congenital diaphragmatic hernia (CDH) is characterized by a defect in the diaphragm that permits abdominal viscera to herniate into the chest. These herniated viscera are thought to compress the growing lung and cause lung parenchymal and vascular hypoplasia. The genetic defects that cause the diaphragmatic defect may also contribute primarily to lung hypoplasia. Postnatal reduction of the herniated abdominal viscera and correction of the diaphragmatic defect are easily achievable, but the lung hypoplasia persists, often leading to persistent fetal circulation and respiratory failure. This article reviews the experimental basis of fetal therapy for CDH and the US clinical experience with tracheal occlusion.

Prenatal prediction of survival in isolated diaphragmatic hernia using observed to expected total fetal lung volume determined by magnetic resonance imaging based on either gestational age or fetal body volume

OBJECTIVES

To compare the predictive value of the prenatal observed to expected (o/e) lung volume as measured by fetal magnetic resonance imaging (MRI), based on an algorithm using either the gestational age or fetal body volume (FBV), for neonatal survival of fetuses with isolated congenital diaphragmatic hernia (CDH).

METHODS

We included 53 fetuses with a prenatal diagnosis of isolated CDH, 26 without and 27 with prenatal tracheal occlusion, who were assessed by fetal MRI, liveborn after 32 weeks, and in whom follow-up until discharge from the neonatal care unit was available. Measurements of lung volumes were expressed as a percentage of the appropriate mean (o/e total fetal lung volume (TFLV) x 100) either for gestational age or for FBV. Measurements of FBV were expressed as a percentage of the appropriate mean (o/e FBV x 100) for gestation. Fetuses with prenatal intervention were all assessed > or = 24 h after balloon removal. Regression analysis was used to examine the effect on postnatal survival of either o/e TFLV based on gestational age or based on FBV, gestation at delivery, side of CDH, intrathoracic position of the liver and prenatal intervention. Receiver-operating characteristics (ROC) curves were constructed for the prediction of survival by o/e TFLV based on gestational age and o/e TFLV based on FBV, for all fetuses, as well as for those with o/e FBV between 90 and 110% and those with values beyond that range. A power calculation for the number of fetuses needed to show a difference between the ROC curves was performed.

RESULTS

Regression analysis demonstrated that o/e TFLV based on gestational age and on FBV were the only independent predictors of postnatal survival. The area under the ROC curve for prediction of postnatal survival from the o/e TFLV based on gestational age was 0.811, and for that based on FBV it was 0.868 (P < 0.001 for both). For fetuses with o/e FBV between 90 and 110%, and those with values < 90% and > 110%, the area for measurements based on gestational age was 0.895 and 0.733, respectively; when based on FBV it was 0.906 and 0.833 (P < 0.01 for all). A minimum of 273 patients would be needed to provide a probability of 90% of detecting a difference between the areas under both ROC curves.

CONCLUSIONS

In fetuses with isolated CDH, lung volume as measured by fetal MRI was significantly correlated with survival. Prediction tended to be better by o/e TFLV based on FBV rather than gestational age. The difference in the prediction of survival between o/e TFLV based on FBV or gestational age was dependent on fetal biometry.

How useful is the lung-to-head ratio in predicting outcome in the fetus with congenital diaphragmatic hernia? A systematic review and meta-analysis

OBJECTIVE

Fetal surgery to improve lung growth comprises tracheal occlusion in selected 'high-risk' fetuses with congenital diaphragmatic hernia (CDH). Sonographically measured fetal lung-to-head ratio (LHR) is utilized to recruit candidates for fetal surgery. This study provides a meta-analysis of the evidence regarding the prognostic use of lung-to-head ratio measurements in fetal CDH.

METHODS

MEDLINE, SCOPUS and ISI PROCEEDINGS databases were searched for MeSH terms: lung, head, hernia and ratio. References in retrieved studies were also searched. Studies were categorized as follows: Phase I studies measured normal fetal LHR; Phase II studies compared fetal LHR in CDH survivors and non-survivors (if LHR informed therapy decisions or LHR was not measured during the window for intervention (< 32 weeks' gestation), studies were excluded); Phase III studies used LHR to guide selection for fetal surgery (non-randomized trials were excluded); Phase IV studies measured CDH survival before and after LHR application in clinical practice.

RESULTS

The one Phase I study showed that LHR varied substantially with gestation and technique. No complete studies met the selection criteria for Phase II: meta-analysis of subgroups revealed similar LHR in CDH survivors and non-survivors. A single Phase III study revealed no benefit for LHR-directed fetal surgery. No Phase IV studies were identified.

CONCLUSION

The prognostic use of LHR in fetal CDH entered clinical practice prior to publication of robust normal data and is not supported by current evidence. Application of a structured approach to any 'new' prognostic test could improve its validity and clinical application.

Pleural and pericardial effusion: a potential ultrasonographic marker for the prenatal differential diagnosis between congenital diaphragmatic eventration and congenital diaphragmatic hernia

OBJECTIVES

To determine whether or not the presence of pleural and/or pericardial effusion can be used prenatally as an ultrasonographic marker for the differential diagnosis between diaphragmatic eventration and diaphragmatic hernia.

METHODS

We present two case reports of non-isolated diaphragmatic eventration associated with pleural and/or pericardial effusion. Additionally, we reviewed the literature for all cases of congenital diaphragmatic hernia (CDH) and diaphragmatic eventration that met the following criteria: (1) prenatal diagnosis of a diaphragmatic defect and (2) definitive diagnosis by autopsy or surgery. The frequencies of pleural effusion, pericardial effusion and hydrops were compared between the two conditions using Fisher's exact test. A subanalysis was conducted of cases with isolated diaphragmatic defects (i.e. diaphragmatic defects not associated with hydrops and other major structural or chromosomal anomalies).

RESULTS

A higher proportion of fetuses with diaphragmatic eventration had associated pleural and pericardial effusions compared with fetuses with diaphragmatic hernia (58% (7/12) vs. 3.7% (14/382), respectively, P < 0.001). This observation remained true when only cases of diaphragmatic defects not associated with hydrops and other major structural or chromosomal anomalies were compared (29% (2/7) with eventration vs. 2.2% (4/178) with CDH, P < 0.02).

CONCLUSIONS

The presence of pleural and/or pericardial effusion in patients with diaphragmatic defects should raise the possibility of a congenital diaphragmatic eventration. This information is clinically important for management and counseling because the prognosis and treatment for CDH and congenital diaphragmatic eventration are different. Published by John Wiley & Sons, Ltd.

Outcomes of congenital diaphragmatic hernia: a population-based study in Western Australia

OBJECTIVES

There have been many recent reports of improved survival rates for congenital diaphragmatic hernia (CDH), largely derived from institution-based data. These are often flawed by case selection bias. The objectives of this study were to document the true incidence, management, and outcomes of CDH in a geographically defined population over a 12-year period and to determine the changing trends in these over time. We also sought to ascertain the prenatal and postnatal factors associated with morbidity and death among these infants.

METHODS

A retrospective study of all cases of CDH in Western Australia from 1991 to 2002 was conducted. Cases were identified from 5 independent databases within the Western Australian health network, including the Western Australian Birth Defects Registry. All fetuses and neonates diagnosed with CDH in Western Australia during this period were identified, including miscarriages, stillbirths, and terminations of pregnancies in which a diagnosis of fetal CDH had been made, as well as those diagnosed postnatally. Cases not known to involve CDH until diagnosis at autopsy were also included. Infants with diaphragmatic eventration were excluded from the study. Detailed information was obtained from review of maternal and infant medical records.

RESULTS

One hundred sixteen cases of CDH were identified. Of these, 71 (61%) infants were born alive and 37 survived beyond 1 year of age (52% of live-born infants, 32% of all cases of CDH). Pregnancies involving 38 (33%) fetuses were terminated electively, 4 (3%) fetuses were aborted spontaneously, and 3 (3%) fetuses were stillborn. Another major congenital anomaly was present in 54 (47%) cases. Twenty-one (18%) cases had other anomalies that were likely to be fatal. Of all cases with an additional major anomaly, 42 (78%) died. Twenty-seven (71%) of 38 fetuses for whom the pregnancy was terminated had another major anomaly. Twenty-three (32%) live-born infants had another major anomaly (4 of which were considered fatal conditions); however, this did not affect their survival rates. Fifty-three percent of cases were diagnosed prenatally, and 49% of these pregnancies were then terminated. Of live-born infants with prenatally diagnosed CDH, 10 (33%) survived beyond 1 year of age. The gestational age at diagnosis did not affect the survival rate for live-born infants. Postnatal diagnosis occurred in 55 (47%) cases. Of these, 41 (74%) case subjects were born alive and diagnosed on clinical grounds after birth. In the remaining 14 cases, the diagnosis was made in postmortem examinations of fetuses from pregnancies that were terminated for other reasons (8 cases) or after spontaneous abortion or stillbirth (5 cases). Significant differences were found between prenatally and postnatally diagnosed live-born infants. Among live-born infants, prenatal diagnosis was associated with a significantly reduced survival rate (33%, compared with 66% for postnatally diagnosed infants). Prenatally diagnosed live-born infants were of lower birth weight and were born at an earlier gestational age. There was no statistically significant difference between the 2 groups in the onset of labor (spontaneous or induced) or in the rate of elective cesarean sections. Prenatally diagnosed live-born infants were more likely to be delivered in a tertiary perinatal center and were intubated more commonly at delivery. No difference was found in the Apgar scores at either 1 or 5 minutes between the groups. Of 71 live-born infants, 37 (52%) survived to 1 year of age. The majority of deaths occurred within the first 7 days of life (44%). Preoperative air leaks occurred for 16 (22%) infants, of whom 14 (88%) died. Factors found to predict death of live-born infants included prenatal diagnosis, right-sided hernia, major air leak, earlier gestational age at birth, lower birth weight, and lower Apgar scores at 1 and 5 minutes. Over the course of the decade, there were significant increases in the proportion of cases in which the diagnosis of CDH was made with prenatal ultrasonography and in the number of live-born infants born at the tertiary perinatal center. The mortality rate for all cases, the mortality rate for live-born infants, and the proportion of pregnancies involving prenatally diagnosed cases that were terminated electively were all greater in the later epoch but not significantly so.

CONCLUSIONS

This was a comprehensive, population-based study of CDH, with full case ascertainment, large sample size, and complete outcome data for all cases. The majority of published studies of CDH examined specific patient populations, such as neonates referred to tertiary pediatric surgical centers. Invariably, those studies failed to detect the demise of cases with CDH before arrival at the referral center, whether through termination of pregnancy, in utero fetal demise, or postnatal death occurring before transfer. Exclusion of these cases from calculations of mortality rates results in significant case selection bias. In our study, 35% of live-born infants died before referral or transport. The population of infants reaching the tertiary surgical center represented only 40% of the total cases of CDH. Wide variations in reported survival rates occur throughout the literature. These differences reflect the influence of this case selection bias, as well as variable referral policies and management practices. For our study population, survival rates differed vastly depending on the subgroup analyzed. Ninety-two percent of postoperative infants survived beyond 1 year of age, as did 80% of infants who reached the surgical referral center. However, only 52% of live-born infants, 32% of all cases, and 16% of all prenatally diagnosed cases survived. Therefore, the overall mortality rate for this condition remains high, despite increased prenatal detection, transfer to tertiary institutions for delivery, and advances in neonatal care, and is influenced significantly by the rate of prenatal termination. In our study, 33% of all cases of CDH and 49% of prenatally diagnosed fetuses underwent elective termination of pregnancy. This large number of fetal terminations confounds the accurate assessment of the true outcomes of this condition.

Fetal Relative Lung Volume: Quantification by Using Prenatal MR Imaging Lung Volumetry

PURPOSE

To retrospectively determine a biometric algorithm for calculating relative lung volume in fetuses with normal lungs and of a wide range of gestational ages by using proved independent variables and to retrospectively investigate the use of this algorithm in fetuses with pulmonary hypoplasia.

MATERIALS AND METHODS

Total lung volume (TLV) was measured by using planimetry on single-shot rapid acquisition with relaxation enhancement magnetic resonance (MR) images obtained in 91 fetuses with ultrasonographically (US) normal chests and 28 fetuses with US-determined pulmonary hypoplasia. All fetuses were aged between 18 and 38 weeks gestation. Analysis of covariance was used to identify parameters that were not different between the fetuses with US-determined normal and those with US-determined abnormal chests, and these variables were used to construct an algorithm for calculating predicted lung volume. The relative lung volume-that is, the observed lung volume expressed as a percentage of the predicted lung volume-was then calculated in fetuses with pulmonary hypoplasia.

RESULTS

There was no significant difference in mean maternal or gestational age between the two fetus groups. Stepwise regression analysis was used to generate the following equation for predicting fetal lung volume on the basis of independent biometric indexes, with a correlation coefficient of 0.93: TLV = (0.52 . LV) + (0.33 . BD) - (0.06 . FL) - 13.7, with TLV and liver volume (LV) in milliliters and biparietal diameter (BD) and femoral length (FL) in centimeters. In the fetuses with normal chests, relative lung volume varied between 51% and 134%. In the fetuses with pulmonary hypoplasia, relative lung volume varied between 6% and 70%.

CONCLUSION

The predicted lung volume in fetuses of a wide range of gestational ages can be calculated with a high degree of accuracy, enabling prenatal MR imaging lung volumetry in which relative lung volume is used to quantify fetal pulmonary hypoplasia.

Current therapy of infants with congenital diaphragmatic hernia

Congenital diaphragmatic hernia (CDH) is a life-threatening anomaly with a significant mortality rate. Despite widespread prenatal diagnosis, few parameters have been well defined to aid in prediction of outcome of these infants. Antenatal maternal steroid administration and foetal surgery are not proven interventions. Postnatal treatment has changed over the last 10 years, with avoidance of hyperventilation and ventilator-induced lung injury resulting in improved survival. Therapies such as inhaled nitric oxide, exogenous surfactant administration and extracorporeal membrane oxygenation (ECMO) have undergone limited study, but show no clear benefit in this population. With improved outcome, principally due to avoidance of barotrauma, greater opportunity exists for long-term evaluation of survivors. To date, continuing problems with pulmonary function, nutrition and growth, effects of right ventricular hypertension and developmental issues have been identified. Through co-ordinated, multidisciplinary evaluation of CDH survivors, improved long-term outcome for these challenging patients can be attained.

Congenital diaphragmatic hernia in Scandinavia from 1995 to 1998: Predictors of mortality

BACKGROUND/PURPOSE

There is a lack of large contemporary studies on the management of congenital diaphragmatic hernia (CDH), and the prediction of mortality remains difficult. The aim of this study was to investigate the influence of perinatal factors on mortality rate in a contemporary multicenter study.

METHODS

The authors conducted a retrospective multicenter cohort study. Twelve of 13 Scandinavian pediatric surgical centers participated in the study. During a 4-year period (1995 through 1998) 195 children with CDH were included. The main endpoints were hospital mortality rate and total mortality rate (before 2001). Bivariate and multivariate survival analyses were performed using Kaplan-Meier plots, Log-rank test, and Cox regression.

RESULTS

Overall hospital mortality rate was 30%. Among 168 neonates with symptoms within 24 hours (early presenters) 35% died before discharge. All 61 deaths occurred in 157 neonates with symptoms within the first 2 hours of life. Among early presenters, 27% had prenatal ultrasound diagnosis, 26% were delivered by cesarean section, and 21% had associated major malformations. Bivariate analysis of early presenters showed increased risk of death in neonates with prenatal diagnosis, associated anomalies, right-sided diaphragmatic hernia (RCDH), low 1-minute and 5-minute Apgar scores, low birth weight, short gestational age, and cesarean delivery. Neonates with prenatal diagnosis were characterized by significantly lower Apgar scores, lower birth weight, and increased frequency of associated anomalies than those diagnosed after birth. Multivariate analysis found that prenatal diagnosis (P =.004), 1-minute Apgar (P =.001), and RCDH (P =.042) were independent predictors of total mortality rate.

CONCLUSIONS

In a series of 195 CDH patients, all 61 deaths occurred in the 157 neonates presenting with symptoms within the first 2 hours of life. Prenatal diagnosis, 1-minute Apgar score, and RCDH were significant independent predictors of total mortality.

Ultrasonographic measurement of the abdominal circumference in fetuses with congenital diaphragmatic hernia

OBJECTIVE

To determine whether ultrasonographic measurements of the abdominal circumference are smaller in fetuses with congenital diaphragmatic hernia and whether this is reflected as an underestimation of the estimated fetal weight.

STUDY DESIGN

A retrospective review of 225 abdominal circumference measurements made between 24 and 41 weeks of gestation in 85 fetuses with congenital diaphragmatic hernia was performed. The individual and mean abdominal circumference value at each week of gestation versus gestational age was plotted and compared with normative data. Comparisons between abdominal circumference measurements and hernia variables were made with the chi(2) test. The Pearson correlation was used to examine the accuracy of ultrasonographic determination of the estimated fetal weight.

RESULTS

The mean measurements of abdominal circumference were not found to differ significantly from normative data until term, although fetuses with liver herniation were less likely to have measurements more than 2 standard deviations below the mean. Calculation of estimated fetal weight was similar in accuracy to that in normal fetuses.

CONCLUSION

Small abdominal circumference measurements should not be expected in fetuses with congenital diaphragmatic hernia. Abnormalities of the abdominal circumference or an abdominal circumference-dependent estimated fetal weight should not be attributed to the anatomic defect without considering other etiologies.

Outcome of congenital diaphragmatic hernia

The outcome of congenital diaphragmatic hernia (CDH) differs for different stages of the fetus or infant's life (i.e., antenatal, immediate postnatal, and postoperative). Assessing combined data from nonrandomized studies is technically difficult. Following recognized methods of reviewing such trials, we aimed to review the available literature on the outcome of CDH to provide a guide to clinicians when counselling parents who have a fetus/infant with this condition. Thirty-five studies reporting data for CDH from 1985 to March 1998 were identified using a high sensitive search strategy, hand-searching journals, and reviewing references of relevant studies. These were systematically reviewed. The median overall mortality was 58% (interquartile range (IQR), 43-65%) for babies diagnosed in utero, 48% (IQR, 35-55%) if born alive, and 33% (IQR, 18-54%) postoperatively. Diagnosis before 25 weeks of gestation is not a uniformly bad prognostic indicator (median mortality, 60%). Outcome was worse for those fetuses with other anomalies (median mortality, 93%). The median percentage mortality for all infants born alive and treated in extracorporeal membrane oxygenation (ECMO) centers was 34% (IQR, 26-47%). Median percentage mortality for all ECMO-treated infants was 44% (IQR, 35-50%). Different treatment strategies may have a variable impact on outcome. These figures, together with local data, may help in parental counselling on prognosis for fetuses/infants with CDH.

Congenital diaphragmatic hernia: a meta-analysis of mortality factors

PURPOSE

The aim of this study was to review all available studies reported in the English-language literature from 1975 through 1998, and by meta-analysis assess the importance of prenatal diagnosis, associated malformations, side of hernia, timing of surgery, and study population on mortality rates in patients with congenital diaphragmatic hernia (CDH).

METHODS

One-hundred-two studies were identified, and 51 studies (2,980 patients) fulfilled the prespecified inclusion criteria. Studies were grouped according to study population into: (I) fetuses diagnosed prenatally; (II) neonates admitted to a treatment center; and (III) population-based studies.

RESULTS

Pooled total mortality rate was significantly higher in category I than in category III (75.6% v 58.2%, P < .001). Pooled hidden postnatal mortality rate (deaths before admittance to a treatment center) in population-based studies was 34.9%. Prenatally diagnosed patients in both category II and III had significantly higher mortality rates than those diagnosed postnatally. Mortality rates were significantly higher among CDH infants with associated major malformations compared with isolated CDH in all 3 categories. An increased mortality rate in right-sided CDH was found in category II and III.

CONCLUSIONS

Prenatal diagnosis of CDH, presence of associated major malformations, and the study population have a major influence on mortality rate. The very high mortality rate in studies of fetuses with a prenatal diagnosis of CDH should be taken into account in prenatal counselling.