437 - Critical Congenital Heart Disease Screening at Altitude: A Review of Performance, Cost, and Diagnostic Implications

Publication Number: 3422.437

Angela J. Shin, University of Colorado School of Medicine, Aurora, CO, United States; Sheila Pahlavan, Children's Hospital Colorado, Denver, CO, United States

Background: Pulse oximetry screening (POS) for critical congenital heart disease (CCHD) improves early detection and outcomes, including morbidity and mortality. At high altitudes, physiologic reductions in neonatal oxygen saturation increase false-positive rates, leading to more echocardiograms and potential overutilization of healthcare services. Altitude-related hypoxemia may influence decisions around home oxygen use in newborns.

Objective: 1. Assess the impact of altitude on CCHD screening, diagnostic yield, healthcare utilization, and cost-effectiveness
2. Evaluate the utility of altitude-adjusted screening algorithms

Design/Methods: We conducted a literature review of peer-reviewed, scholarly journal articles through August 2025. Databases searched included PubMed, Scopus, and the Cochrane Library. Search terms included “CCHD,” “pulse oximetry,” “altitude,” “echocardiogram,” and “healthcare utilization.” Studies were included if they reported CCHD screening outcomes of neonates born at moderate or high altitude and included data on outcomes with echocardiogram use or related interventions. Excluded articles included case reports without systematic screening data, studies lacking POS, studies focused on prenatal CCHD detection, and studies lacking altitude-relevant analyses.

Results: Healthy neonates at altitude exhibit mean oxygen saturation 2–3% lower than at sea level. Above ~6,000 ft, first-pass rates decline under standard thresholds. Modified screening algorithms that lower the pass threshold to ≥93% improve first-pass rates without documented missed CCHD. Two altitude-specific algorithms demonstrated high specificity and negative predictive value, further supporting tailored screening. Altitude-aware algorithms reduce repeat screens and unnecessary testing, with variable trade-offs in specificity. Altitude-related hypoxemia may increase healthcare utilization relative to sea level. Cost analyses show that POS remains cost-effective, but altitude-related false-positive rates increase diagnostic costs.

Conclusion(s): Most studies are single-center and observational, use variable definitions of altitude, and report inconsistent post-discharge outcomes. Few studies directly measure cardiology referral rates or home oxygen use. Altitude-adjusted thresholds maintain detection rates while reducing unnecessary echocardiograms and may help mitigate costs and overutilization of resources. Further research is needed to quantify the downstream impact of home oxygen prescriptions and to validate screening protocols across high-altitude regions.