227 - Predictive Value of Patent Foramen Ovale Measured at Birth for Development of Atrial Septal Defect in Extremely Low Birthweight Infants

Poster Number: 227
Publication Number: 227.221

Sheema Gaffar, Keck School of Medicine of the University of Southern California, Los Angeles, CA, United States; Rowena G. Cayabyab, LAC+USC MEDICAL CENTER, LOS ANGELES, CA, United States; Bijan Siassi, LAC+USC Medical Center, Los Angeles, CA, United States; Mahmood Ebrahimi, Keck School of Medicine of the University of Southern California, Los Angeles, CA, United States; Merujan Uzunyan, LAC+USC, LOS ANGELES, CA, United States; Lorayne Barton, LAC+USC Med Ctr, Los Angeles, CA, United States; Rangasamy Ramanathan, Keck School of Medicine of USC, Los Angeles, CA, United States

Background: The foramen ovale (FO) is a fetal channel that allows right-to-left (R-L) shunting throughout cardiovascular development. After birth, some term infants have minor incompetence of the flap valve, allowing a small left to right (L-R) shunt that usually resolves, while a higher percentage of premature infants have persistent FO which lasts after birth.

Objective: The aim of this study is to evaluate the echocardiographic change in FO size with postnatal growth to determine if progression to atrial septal defect (ASD) can be predicted in extremely low birth weight (ELBW) infants.

Design/Methods: This descriptive study encompassed all inborn ELBW infants admitted to neonatal intensive care unit between 2015 and 2021 who had echocardiograms (ECHO) performed in the first week of life and before discharge. Size of valve-incompetent FO was determined by measuring the width of L-R color doppler flow in subcostal coronal posterior and sagittal subcostal viewing windows. The largest measurement was taken as diameter of the septal defect.

Results: Forty-six infants with median gestational age (GA) of 25 weeks (IQR; 24-26) and median birth weight (BW) of 765 grams (IQR; 645-840) were included. First ECHO was obtained at median postnatal day of life (DOL) 2 (range 1-3). Forty-four infants had initial median FO diameter of 1.9 mm at birth that grew to 2.1 mm by 36 weeks median postmenstrual age (PMA). Majority of infants at birth (33/45, 73%) and at discharge (34/43, 79%) had L-R atrial shunt seen. Only 1 infant (1/46, 2.2%) at birth and 3 infants (3/46, 6.5%) at discharge had no flow seen, suggesting closed FO. In contrast, 2 ELBW infants born at median GA of 25 weeks (range 24-25) and median BW of 690 grams (range 644-735) had initial FO diameter of 3.7 mm (range 3.4-4.0) on median postnatal DOL 1 (range 0-2) that grew into a 7.0 mm (range 6.4-7.5) septal defect by 40 weeks PMA. Both infants had L-R atrial-level shunt on discharge. Table shows other echocardiographic parameters measured that were within normal limits.Conclusion(s): This study demonstrated that in ELBW infants, FO greater than 3 mm in diameter at birth enlarges with postnatal growth to possibly become an ASD that needs echocardiographic follow-up as outpatient compared to FO less than 3 mm, which does not increase in size with advancing postnatal age. If these large defects are confirmed as ASD on follow-up echocardiograms, our data shows 4% incidence at the time of discharge, suggesting higher incidence of secundum ASD in ELBW infants compared to term infants. Further study of a larger population of ELBW infants is needed to confirm this finding.
Gaffar Sheema CV for PAS.pdf