Role of NT-ProBNP in Differentiating Cardiac and Non-Cardiac Causes of Dyspnea in Patients Presenting to the Emergency Department of a Tertiary Care Teaching Hospital

Background: Dyspnea is a common presenting symptom in emergency departments (ED), with diverse etiologies ranging from cardiac to pulmonary causes.Rapid differentiation between cardiac and non-cardiac origins is crucial for appropriate management.This pilot study aimed to evaluate the diagnostic utility of N-terminal pro-brain natriuretic peptide (NT-proBNP) in distinguishing cardiac from non-cardiac causes of dyspnea in ED patients at a tertiary care teaching hospital.Methods: A prospective observational study was conducted over 3 months.Fifty adult patients presenting to the ED with acute dyspnea were enrolled.Clinical assessment, routine investigations, and NT-proBNP levels were measured upon admission.Receiver operating characteristic (ROC) curve analysis was performed to determine the optimal NT-proBNP cutoff value.Results: Of the 50 enrolled patients (mean age 62.514.3years, 54% male), 28 (56%) were diagnosed with cardiac causes of dyspnea, while 22 (44%) had non-cardiac etiologies.The median NT-proBNP level was significantly higher in patients with cardiac causes (1,850 pg/mL, IQR: 980-3,200) compared to non-cardiac causes (210 pg/mL, IQR: 90-450, p<0.001).ROC curve analysis yielded an area under the curve of 0.89 (95% CI: 0.80-0.98).An NT-proBNP cutoff value of 800 pg/mL demonstrated a sensitivity of 82% and specificity of 86% for identifying cardiac causes of dyspnea.The positive and negative predictive values were 88% and 79%, respectively.Conclusion: NT-proBNP showed promising results as a biomarker for differentiating cardiac from non-cardiac causes of dyspnea in ED patients.