99 - Urinary N-Terminal-Pro-Brain Natriuretic Peptide (NT-pro-BNP) As A Predictor of Outcomes in Congenital Diaphragmatic Hernia - A Prospective Pilot Study

Poster Number: 99
Publication Number: 99.2217

Background: Pulmonary hypertension (PH), and cardiac dysfunction seen in Congenital Diaphragmatic Hernia (CDH) is best assessed using echocardiography (echo). A biomarker of cardiac dysfunction or severity of PH would be very valuable clinically (cheap and faster turnaround time) as an adjunct to echo. N-terminal brain Natriuretic Peptide (NT-Pro BNP) is one such biomarker that is secreted from the cardiac ventricles in response to wall stress. Plasma NT-proBNP has been studied in the CDH population.

Objective: Our objective was to investigate the utility of urinary NT-proBNP as a novel adjunct to predict PH and cardiac dysfunction in CDH.

Design/Methods: Prospective observational study of neonates with CDH enrolled from May 2022. Urine samples to detect NT-proBNP levels and corresponding plasma NT-proBNP levels were collected at 24 Hours of life (HOL) and at the time of the first echo. Urinary NT-proBNP and its ratio to urinary creatinine (UNBCR) were analyzed using VITROS 7600 ECi/ECiQ Immunodiagnostic Systems. Spearman’s correlation was used to quantify the association between urinary and plasma NT-ProBNP values. Logistic regression and receiver operating characteristic (ROC) curve analyses were used to test the association of the 24-HOL values with the need for ECMO. The Kruskal-Wallis test was used to test the association between echo parameters with urinary NT-ProBNP and UNBCR values.

Results: In our preliminary analysis of 21 enrolled patients, urinary NT-proBNP (r = 0.492, p = 0.028), and UNBCR (r = 0.665, p = 0.001), exhibited a significant positive correlation with plasma NT-proBNP. Three of the 20 (15%) patients with biomarker data required ECMO. Higher urinary NT-proBNP at the first echo was marginally associated with increased odds of ECMO (p = 0.063, area under ROC curve = 90.2%). Patients with right ventricle systolic pressure (RVp) greater than 2/3rd of systemic pressure had significantly higher urinary NT-proBNP levels at 24 HOL (p=0.044). UNBCR levels (first echo) were significantly higher in patients with moderately depressed qualitative left ventricular (LV) systolic function compared to normal on the first echo (p=0.023).

Conclusion(s): We report that levels at 24 HOL was significantly associated with elevated RVp in CDH. UNBCR level (first echo) was significantly associated with LV dysfunction on the first echo. Although these biomarkers appear to provide good accuracy in predicting the need for ECMO, the small sample size and rarity of ECMO in this data set limited statistical power to find significant associations. Further research with a larger sample size is needed to confirm the results.