Prenatal Diagnosis and Evaluation of Sonographic Predictors for Intervention and Adverse Outcome in Congenital Pulmonary Airway Malformation

Abstract

Objective: To describe antenatal findings and evaluate prenatal risk parameters for adverse outcome or need for intervention in fetuses with congenital pulmonary airway malformation (CPAM).

Methods: In our retrospective study all fetuses with a prenatal diagnosis of CPAM detected in our tertiary referral center between 2002 and 2013 were analyzed. Sonographic findings were noted and measurements of mass-to-thorax-ratio (MTR), congenital pulmonary airway malformation volume-ratio (CVR) and observed to expected lung-to head-ratio (o/e LHR) were conducted and correlated to fetal or neonatal morbidity and mortality and/or need for prenatal intervention.

Results: 67 fetuses with CPAM were included in the study. Hydropic fetuses were observed in 16.4% (11/67) of cases, prenatal intervention was undertaken in 9 cases; 7 pregnancies were terminated. The survival rate of non-hydropic fetuses with conservatively managed CPAM was 98.0% (50/51), the survival rate for hydropic fetuses with intention to treat was 42.9% (3/7). 10 (18.2%) children needed respiratory assistance. Fetuses with a CVR of <0.91 were significantly less likely to experience adverse outcome or need for prenatal intervention with sensitivity, specificity and positive/negative predictive value of 0.89, 0.71, 0.62 and 0.93, respectively. A MTR (mass-to-thorax-ratio) of < 0.51 had a positive predictive value of 0.54 and a negative predictive value of 0.96 of adverse events with a sensitivity of 0.95 and a specificity of 0.63. The negative predictive value for o/e LHR of 45% was 0.84 with sensitivity, specificity and positive predictive value of 0.73, 0.68 and 0.52, respectively.

Conclusions: The majority of cases with CPAM have a favorable outcome. MTR and CVR are able to identify fetuses at risk, the o/e LHR is less sensitive.

Fig 1. Flow chart showing management and pregnancy outcome of 67 fetuses with prenatally diagnosed CPAM.

Fig 2. Transverse section of the fetal thorax at 25 weeks of gestation demonstrating a macrocystic congenital pulmonary airway malformation (CPAM) drained by an inserted double pigtail catheter (Harrison Fetal Bladder Stent Set).

Fig 3. Transverse and longitudinal section of the fetal thorax demonstrating a large microcystic congenital pulmonary airway malformation (CPAM) with mediastinal shift at 19 weeks of gestation.

CVR (CPAM volume ratio): 2.88 x 1.77 x 2.31 x 0.52/16.1 (head circumference) = 0.38.

Fig 4. Receiver operator characteristics curve for the congenital pulmonary airway malformation-volume ratio (CVR) and composite adverse outcome or need for intervention.

Fig 5. Transverse section of the fetal thorax at 19 weeks of gestation demonstrating a large macrozystic congenital pulmonary airway malformation (CPAM) with severe mediastinal shift.

MTR (Mass-to-thorax ratio): 26.9 / 42.3 = 0.63.

Fig 6. Receiver operator characteristics curve for Mass-to-thorax ratio (MTR) and composite adverse outcome or need for intervention.

Fig 7. Receiver operator characteristics curve for observed to expected lung-to-head ratio (o/e LHR) and composite adverse outcome or need for intervention.

Fig 8. Detectionrate in % of adverse events (perinatal death, hydrops, prenatal intervention or need for respiratory assistance) at a cutoff of 0.51 mass-to-thorax rate (MTR) in comparison to fetuses without adverse events.

Fig 9. Detectionrate in % of adverse events (perinatal death, hydrops, prenatal intervention or need for respiratory assistance) at a cutoff of 0.91 CPAM volume ratio (CVR) in comparison to fetuses without adverse events.

Fig 10. Detectionrate in % of adverse events (perinatal death, hydrops, prenatal intervention or need for respiratory assistance) at a cutoff of 45% observed to expected Lung to head ratio (LHR) in comparison to fetuses without adverse events.