Fetal Risk Stratification and Outcomes in Children with Prenatally Diagnosed Lung Malformations

Abstract

Objective: The aim of this study was to assess current clinical outcomes in children with prenatally diagnosed congenital lung malformations (CLMs) and to identify prenatal characteristics associated with adverse outcomes. Summary Background Data: Despite a wide spectrum of clinical disease, the identification of fetal CLM subgroups at increased risk for hydrops and respiratory compromise at delivery has not been well defined. Methods: A retrospective cohort study was conducted using an operative database of prenatally diagnosed CLMs managed at 11 children’s hospitals from 2009 to 2016. Statistical analyses were performed using nonparametric bivariate or multivariable logistic regression. Results: Three hundred forty-four children were analyzed. Fifteen (5.5%) fetuses were managed with maternal steroids in the setting of hydrops, and prenatal surgical intervention was uncommon (1.7%). Seventy-five (21.8%) had respiratory symptoms at birth, and 34 (10.0%) required neonatal lung resection. Congenital pulmonary airway malformation volume ratio (CVR) measurements were recorded in 169 (49.1%) cases and were significantly associated with perinatal outcome, including hydrops, respiratory distress at birth, need for supplemental oxygen, neonatal ventilator use, and neonatal resection (P < 0.001). An initial CVR ≤1.4 was significantly correlated with a reduced risk for hydrops [area under the curve (AUC), 0.93; 95% confidence interval (CI), 0.87–1.00]. A maximum CVR <0.9 (AUC, 0.72; 95% CI, 0.67–0.85) was associated with a low risk for respiratory symptoms at birth. Conclusions: In this large, multi-institutional study, an initial CVR ≤ 1.4 identifies fetuses at very low risk for hydrops, and a maximum CVR < 0.9 is associated with asymptomatic disease at birth. These findings represent an opportunity for standardization and quality improvement for prenatal counseling and delivery planning.

Narrative review of congenital lung lesions

“…The overall perinatal prognosis of a fetus affected by the lung malformation is strongly associated with its overall growth during pregnancy rather than by its underlying histology (5). This concept has been supported in numerous studies, all which have shown that mass size, as opposed to type of lesion, is most predictive of perinatal outcome based on a variety of outcome measures, including fetal hydrops, neonatal respiratory symptoms, and likelihood of lung resection in the newborn period (5,20,22,23). The most common metric for lesion size is the CPAM volume ratio (CVR), which measures the three-dimensional size of the lesion relative to the fetal head circumference (24).…”

“…Approximately 70% of all congenital lung malformations are now detected during fetal anatomic survey (Figure 5) (20). While ultrasound is a useful tool for the detection of hyperechoic and cystic lung lesions, there is definite potential to misdiagnose primary fetal lung masses for other anomalies.…”

“…CVRs are helpful since they are adjusted for fetal size and therefore can be used to track relative growth of the lung lesion over time. Although many maternal-fetal medicine providers have historically focused on secondary parameters, such as polyhydramnios or mediastinal shift, more recent multicenter data suggests that the maximum CVR during gestation is the best predictor of perinatal outcome (20). In the majority of children with small lung lesions, prenatal MRI usually adds little additional diagnostic information that would change management and is therefore probably not costeffective (25).…”

“…A proposed CVR-based algorithm based on recent data from the Midwest Pediatric Surgery Consortium is shown in Figure 6 (20). Peak CVRs less than 0.9-1.0 throughout the pregnancy are highly predictive (>90%) of asymptomatic disease at birth (Figure 7) (5).…”

“…Fortunately, hydrops probably occurs in fewer than 10% of cases based on a multi-institutional report (1). Fetuses at increased hydrops risk are those with an initial CVR of at least 1.4 (20,24). Although many fetuses with high CVRs will not develop hydrops, this group remains clearly at increased risk for respiratory symptoms and may require ventilator support in the neonatal intensive care unit, emergency lung resection, and less commonly, extracorporeal membrane oxygenation (ECMO).…”