(1063) Change in Congenital Pulmonary Airway Malformations Volume Ratio Following Prenatal Steroids

Congenital pulmonary airway malformations (CPAM) are lung lesions typically diagnosed on prenatal ultrasound. The CPAM volume ratio (CVR) prognosticates outcomes, with a value > 1.6 concerning for fetal hydrops and demise. Type II CPAMs are microcystic lesions thought to be the most responsive to maternal steroids; however, a majority of providers administer steroids for all lung lesions with a CVR > 1.6.  Little is known, however, about the change in CVR following steroids. Thus, we sought to determine the effects of steroids on CVR.

Study Design:

We performed a retrospective review of CPAMs managed at our institution between January 1, 2012 and July 1, 2022. CVR was calculated by dividing the cyst volume by the head circumference on ultrasound.   We divided the cohort into four groups:  all lung lesions that did not receive steroids, Type II CPAMs that did not receive steroids, all lung lesions that did receive steroids, and Type II CPAMs that did receive steroids.  Type II CPAMs were diagnosed by post-resection pathology.

Results:

During the study period, we evaluated 199 fetuses with a lung lesion.  Among them, 79 fetuses had longitudinal ultrasounds sufficient for analysis, and 27 (34.0%) were treated with steroids.  While the all lung lesions group not receiving steroids initially had a slight increase in CVR after diagnosis, all other groups had a marginal reduction in CVR (Table).  By 32 weeks’ gestation, all groups had a substantial reduction in CVR; however, this change was more pronounced within the two groups receiving steroids (Table).  The Figure illustrates changes in CVR throughout gestation for all groups.    

Conclusion:

The natural progression for all lung lesions is a reduction in size throughout gestation.  Despite the notion that Type II CPAMs are more responsive to steroids, all lung lesions that received steroids had a greater than 45% reduction between diagnosis and 32 weeks’ gestation.  This is the first report to describe changes in CVR following steroid administration in utero.  Future studies will focus on effects of steroids on hydrops and postnatal outcomes.