Prognostic Value of Pulmonary Doppler to Predict Response to Tracheal Occlusion in Fetuses with Congenital Diaphragmatic Hernia

Abstract

Pulmonary Doppler may play an important role in the prediction of survival and postnatal morbidity in fetuses with congenital diaphragmatic hernia treated with fetoscopic tracheal occlusion (FETO). Spectral Doppler indexes such as pulsatility index and peak early diastolic reversed flow could help to refine the selection of fetuses that might benefit from fetal therapy. When combined with lung-to-head ratio (LHR), these Doppler indices allow to discriminate cases with moderate-to-high survival rates from fetuses with extremely low chances to survive after FETO. In addition, they discriminate groups with a high or low risk of serious neonatal morbidity in surviving fetuses. After therapy, the combined evaluation of the relative increase of LHR with the increase in lung tissue perfusion by power Doppler seems to improve the prediction of fetal survival. In conclusion, while LHR remains the strongest predictive index, Doppler measurements allow to substantially improve the accuracy in the prediction of the chances of survival of fetuses with congenital diaphragmatic hernia treated with FETO.

Use of Data from Predictive Tests following Fetoscopic Endoluminal Tracheal Occlusion for Congenital Diaphragmatic Hernia

“…First, as shown by the same group, many of these measurements are not easily reproducible [5] . Second, as suggested by the same authors, it would be prudent to wait for external validation of these observations by other, independent researchers [2,6] . Third, most of the data were collected on a small subset of patients with isolated left-sided CDH and severe pulmonary hypoplasia who underwent prenatal therapy.…”

“…Third, most of the data were collected on a small subset of patients with isolated left-sided CDH and severe pulmonary hypoplasia who underwent prenatal therapy. Clinical experience with FETO has, however, revealed significant individual variability in the response to FETO, both in lung size as well as vascularization [1][2][3]7] . Fourth, at fetal surgery centers, the population of patients with less severe hypoplasia, and those who despite severe hypoplasia, are expectantly managed during pregnancy, are under-represented.…”

“…It would be more comforting to know whether the pulmonary vascular assessment test can perform well also in the latter group of We have read with interest the recent papers by our partners in the European Program on Soft Tissue Engineering for Children (EuroSTEC -www.eurostec.eu) on the prognostic value of pulmonary Doppler in predicting survival and morbidity of fetoscopic endoluminal tracheal occlusion (FETO) in fetuses with severe isolated left congenital diaphragmatic hernia (CDH) and liver herniation. The value of pulmonary circulation assessment for the prediction of outcome of fetal therapy has been investigated either by using Doppler to evaluate blood vessel resistance and/or actual blood flow, or as response to maternal hyperoxygenation [1][2][3] .On a theoretical basis, the investigation of pulmonary circulation provides independent information that can be combined with that already obtained by measuring the size of the airway compartment and/or the position of the liver. Recent studies also by the FETO consortium confirm that the data obtained with each parameter is not the same.…”

Learning Curve for Intrapulmonary Artery Doppler in Fetuses with Congenital Diaphragmatic Hernia

“…Doppler evaluation of fetal lung circulation has been suggested as a surrogate of lung hypoplasia and intrapulmonary hypertension [2,3,4,5], allowing stratification of CDH cases with a high risk to develop severe neonatal pulmonary hypertension [6,7,8], neonatal morbidity [9] and mortality [6,10,11]. However, intrapulmonary artery Doppler evaluation is a demanding measurement in CDH fetuses due to the difficult observation and insonation of the intrapulmonay artery under a reduced lung size, and concerns exist whether the clinical application of such parameters could be influenced by the operator competences [5]. …”

Left Heart Structures in Human Neonates with Congenital Diaphragmatic Hernia and the Effect of Fetal Endoscopic Tracheal Occlusion

“…During pregnancy, the fetal lungs secrete fluid into the airways, which drain to the amniotic cavity during fetal breathing movements [22]. In animal models and in human work, FETO prevents egress of pulmonary fluid leading to lung tissue stretch, thus triggering lung growth and inducing vascular changes [13,14,15,23,24]. Theoretically, inflation of this balloon also causes an increase in intrathoracic pressure while it also accelerates fetal lung growth, which may minimize the compression effect on the heart from the herniated abdominal structures [8].…”