Pulmonary Score as a Marker of Pulmonary Hypertension Risk Among Preterm Infants

Lindsey Beer, Nationwide Children's Hospital, United States; Waceys Jama, The Abigail Wexner Research Institute at Nationwide Children's Hospital, United States; Brian K. Rivera, The Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH, United States; Sara Conroy, Center for Perinatal Research, The Abigail Wexner Research Institute, Nationwide Children’s Hospital, United States; Carl Backes, Nationwide Children's Hospital, United States; Matthew Kielt, Nationwide Children's Hospital, United States

Background: Pulmonary arterial hypertension (PAH) is a serious complication among extremely preterm infants (EPI; < 28 weeks’ gestation). Most health care providers perform echocardiographic (ECHO) screening for PAH at 36 weeks corrected gestational age (CGA), but the burden of this practice is considerable. While Pulmonary Score has emerged as a valuable indicator of cardiorespiratory disease severity, it’s value in estimating the probability of PAH on ECHO among EPIs has not been previously evaluated.

Objectives: We sought to determine: 1) the prevalence of PAH on ECHO at 36 weeks’ CGA among EPIs and identify variables associated with a positive PAH screen; 2) Pulmonary Score values to estimate the probability of PAH on ECHO at 36 weeks’ CGA.

Design/Methods: Retrospective study at a single, large, pediatric care center (1/2011-1/2021). All EPIs were on nasal cannula [NC], continuous positive airway pressure [CPAP], or mechanical ventilation [MV] at 36 weeks CGA. A PAH-positive ECHO was defined by peak tricuspid regurgitation velocity ≥2.5 m/s and/or 2 or more of the following: right atrial/ventricular enlargement or hypertrophy, ventricular septal flattening, and pulmonary artery dilation. ECHOs were independently reviewed and adjudicated. Patient characteristics (gestational age, birthweight) were compared to identify factors associated with PAH. Pulmonary Scores were calculated as (FiO2respiratory support)+respiratory medications; the score assigns more weight (numeric value) to support that reflects a greater severity of disease (MV=2.5, CPAP=1.5, NC=1.0). Estimated odds ratios and probabilities of PAH for a given Pulmonary Score were from logistic regression models.

Results: Overall, 1,044 ECHOs were reviewed. Among 285 EPIs, 263 (96.8%) received an ECHO at 36 weeks’ CGA (range 35-38 weeks); 75 (25.4%; 95% confidence interval [CI] 24.1%-26.2%) had a PAH-positive ECHO. We observed no difference in patient characteristics among infants with and without PAH. Controlling for gestational age (weeks), the odds ratio of PAH for an infant with a given Pulmonary Score was 1.30 (95% CI: 1.18-1.43); the odds of PAH increases as Pulmonary Score (calculated) increases (figure).

Conclusion: Pulmonary Score is a potential marker to estimate the risk of PAH at 36 weeks CGA among EPIs. Additional studies are needed to better determine if Pulmonary Score can risk-stratify EPIs according to baseline risk of PAH, with a goal towards optimizing patient care and reducing health care burden and cost.