TOP 60 - Screening Above Sea Level: The Impact of Updated AAP CCHD Guidelines in a High-Altitude Birthing Hospital

Publication Number: 4765.TOP 60

Sheila Pahlavan, University of Colorado School of Medicine, Denver, CO, United States; Megan J.. Turner, University of Colorado School of Medicine, Denver, CO, United States; Angela J. Shin, University of Colorado School of Medicine, Aurora, CO, United States

Background: Critical Congenital Heart Disease (CCHD) is a leading cause of neonatal morbidity and mortality, affecting about 6 in 1,000 live births. In 2024, the AAP revised its CCHD screening guidelines, classifying a screen as passing when both pre- and post-ductal oxygen saturations are ≥95% with an absolute difference of ≤3%; any value < 90% is considered an immediate failure. More conservative CCHD screening thresholds may lead to more screen failures in high-altitude birth hospitals, where lower partial pressure of inspired oxygen contributes to delayed transitional newborn lung physiology. Evidence guiding altitude-adjusted thresholds remains limited.

Objective: 1. Compare CCHD screening classifications using the 2011 versus 2024 AAP guidelines
2. Describe the incidence of failed CCHD screenings under each guideline
3. Evaluate downstream healthcare utilization, including echocardiogram use, among newborns with failed CCHD screens in a high-altitude birthing hospital

Design/Methods: We conducted an IRB-exempt retrospective cohort study of all live births at a high-altitude (>5,000 ft) urban safety-net hospital. Eligibility included infants with complete CCHD screen data from January 2019 to October 2025 (n = 23,789). From the EHR, we extracted pre-ductal and post-ductal SpO₂ values along with echocardiographic evaluations and other types of healthcare utilization within 60 days of discharge, when available. Relative to the AAP-defined pass criteria, we defined altitude-modified pass thresholds at ≥90% and ≥93%. Analysis will include descriptive statistics, chi-square tests, and logistic regression to assess associations between screening outcomes and clinical variables.
Preliminary analysis shows 92.6% passed using the AAP ≥95% criteria, 98.8% passed using a ≥93% threshold, and 99.6% passed using a ≥90% cutoff. This reclassifies approximately 6% of newborns as failed solely due to altitude-related lower saturations, although statistical significance has yet to be determined.
In this high-altitude cohort, applying sea-level thresholds substantially increases failed screens and potential downstream testing. Data analysis is ongoing. We will compare past versus present AAP guidelines. Pending outcome linkage, we will quantify false-positive and potential false-negative implications and assess altitude-adjusted thresholds to balance sensitivity and resource utilization. These findings will inform practical, evidence-based screening recommendations for high-altitude birthing hospitals.