INCIDENCE, RISK FACTORS AND OUTCOMES OF PULMONARY HYPERTENSION IN PRETERM INFANTS WITH BRONCHOPULMONARY DYSPLASIA: A SINGLE CENTRE EXPERIENCE

BACKGROUND: Pulmonary hypertension (PH) is a known complication of bronchopulmonary dysplasia (BPD). At our centre, all patients with BPD are screened for PH but its exact incidence and impact on clinical outcomes remains unclear. OBJECTIVES: To determine the incidence of and risk factors for PH in preterm infants with moderate-severe BPD and to compare short-term outcomes in BPD patients with PH and without PH. DESIGN/METHODS: This was a single centre cohort study of preterm infants < 32 weeks GA born between August 2013 and July 2015 with moderate-severe BPD at 36 weeks postmenstrual age. Patients were categorized into BPD+PH (exposure) and BPD alone (control). PH was defined as right ventricular systolic pressure (RVSP) > 40 mmHg or septum flattening in absence of RVSP. Cases of a) RVSP between 30-40 mmHg with normal/unknown septum status and b) RVSP < 40 mmHg with flat septum were defined as “possible PH” (classified as exposure). Predictors of BPD+PH were sought using logistic regression analyses. Outcomes included mortality, growth parameters and NICU resource utilization. Sensitivity analyses were conducted for all outcomes by re-categorizing “possible PH” cases from exposure to control group. A p value of < 0.05 was considered significant. RESULTS: Among 92 BPD patients in study period, 87 had echocardiograms completed of whom 24 (28%) had PH. Baseline characteristics were similar in the two groups with the exception of GA and number of surfactant doses (Table). On multiple logistic regression, after correcting for GA and sex, lack of receipt of antenatal corticosteroids was identified as a significant risk factor for PH (adjusted OR 5.3, 95% CI 1.1-25.1, p = 0.039). There were no significant differences in any outcomes (Table). Similar results were obtained with sensitivity analyses. CONCLUSION: Almost 1 in 3 patients with BPD was identified as having (or possibly having) PH at our centre, with lack of antenatal corticosteroid administration identified as a significant risk factor. No significant differences in outcomes were noted. However, larger prospective studies and long term outcome evaluations are required prior to definitive recommendations regarding screening. Table 1. Selected baseline characteristics and outcomes in BPD patients with and without PH Baseline Characteristics BPD+PH (n=24) BPD alone (n=63) P value GA 24.7 (2.3) 26.4 (3.7) 0.015 BW 785 (458) 840 (268) 0.409 Sex (Female) 37.5 37.1 0.972 Antenatal Steroids 79.2 83.7 0.107* Chorioamnionitis 34.8 26.3 0.449 Prolonged Rupture of Membranes (> 24 h) 25.0 20.6 0.66 Oligohydramnios 4.2 14.3 0.273* Snap II Score 14.0 (13.5) 16.0 (17.0) 0.32 Number of Surfactant doses 1.5 (1.0) 1.0 (1.0) 0.015 Outcome variables BPD+PH (n=24) BPD alone (n=63) P value Survival to discharge 95.8 98.4 0.478 Discharge weight (grams) 3355 (739) 3260 (1146) 0.851 Discharge head-circumference (cm) 35.0 (2.2) 34.3 (3.7) 0.631 Discharged on oxygen 20.8 19.1 1.000 Length of Stay (days) 93.5 (25.5) 93.0 (38.0) 0.566 Duration of invasive ventilation (days) 17.5 (46.0) 13.0 (33.0) 0.905 Duration of non-invasive ventilation (days) 58.0 (22.5) 67.0 (29.0) 0.072 Duration on supplemental oxygen (days) 81.0 (53.0) 66.5 (43.0) 0.435 Note: All categorical variables reported as percentages and all continuous variables as medians (IQR). Selected baseline characteristics and outcomes in BPD patients with and without PH Note: All categorical variables reported as percentages and all continuous variables as medians (IQR).