584 - Pulmonary Vasodilator Use In Very Preterm Infants Admitted to United States Children’s Hospitals

Pulmonary hypertension (PH) is a serious complication of very preterm birth (gestational age (GA) < 32 wk), particularly among infants with bronchopulmonary dysplasia (BPD). Pulmonary vasodilators (PV) are a common yet understudied treatment for these infants. Characterization of contemporary use is needed to inform the design of comparative effectiveness studies.

Objective: To describe PV use and clinical characteristics associated with exposure among very preterm infants admitted to US children’s hospitals.  

Design/Methods:

We used the Pediatric Health Information System (PHIS) to conduct a multi-center retrospective cohort study including very preterm infants born between 22-31 wk GA and discharged between 2011-21 from PHIS hospitals. We excluded infants with major chromosomal or cardiopulmonary abnormalities other than atrial septal defect, ventricular septal defect (VSD) and patent ductus arteriosus (PDA). Each study period day between PHIS hospital admission and the first of death, discharge or one year of age was assessed for exposure to pre-specified PV medications (Table 1). Clinical characteristics associated with PV exposure in bivariable analyses at p < 0.20 were included in multivariable cluster-robust logistic regression models to identify characteristics independently associated with exposure. Bimodal distribution of use identified post-hoc, with early iNO and later use of other PV, motivated independent assessment of characteristics associated with early (< 28 d chronologic age, Table 2) and late ( > 36 wk PMA, Table 3) exposures.

Results: We identified 37428 eligible infants, of which 2358 (6.3%) were exposed to PV for a median of 7.7% of study period days. Inhaled nitric oxide (iNO) (5.8%) was the most common, followed by sildenafil (1.6%) and bosentan (0.4%) (Table 1). Median ages of first exposure to iNO were 28.4 wk PMA and 2.0 wk chronologic age. For all other assessed PV, median ages of first exposure were > 40 wk PMA and > 16 wk chronologic age. Lower GA and SGA status were associated with both early and late PV exposure at p < 0.001. PDA, black race, higher BPD grade and early exposure were all associated with late PV exposure at p < 0.001.

Conclusion(s): Very preterm infants receive PV in early and late peaks. Early exposure in more preterm and SGA infants was significantly associated with later exposure, as were higher BPD grades, PDA and other known risk factors for PH. Characterizing PV use in a large contemporary cohort of very preterm infants is important for identifying opportunities for effective prevention and treatment of PH in future comparative effectiveness studies.