Role of N-Terminal Pro–B-Type Natriuretic Peptide (NT-proBNP) in the Diagnosis of Diastolic Heart Failure and Its Correlation with Echocardiographic Findings

Background: Diastolic heart failure, currently referred to as heart failure with preserved ejection fraction (HFpEF), is a common cardiovascular disorder characterized by impaired ventricular relaxation despite preserved left ventricular systolic function. Early diagnosis remains challenging because clinical manifestations often overlap with other cardiopulmonary conditions. Echocardiography is considered the standard diagnostic modality; however, serum N-terminal pro-B-type natriuretic peptide (NT-proBNP) has emerged as a valuable biomarker for the diagnosis and assessment of disease severity. Aim: To evaluate the role of serum NT-proBNP in the diagnosis of diastolic heart failure and to determine its correlation with echocardiographic findings. Methods: A hospital-based observational analytical study was conducted among 150 patients with clinically suspected diastolic heart failure attending the Department of General Medicine of a tertiary care teaching hospital. Patients fulfilling the inclusion criteria underwent detailed clinical evaluation, laboratory investigations, electrocardiography, chest radiography, and comprehensive two-dimensional Doppler echocardiography. Serum NT-proBNP levels were estimated using an automated electrochemiluminescence immunoassay analyzer. Patients were categorized according to echocardiographic findings, and NT-proBNP levels were compared with demographic characteristics, cardiovascular risk factors, and clinical variables. Statistical analysis was performed using SPSS version 26.0, and a p value of <0.05 was considered statistically significant. Results: Among the 150 study participants, 70.7% were non-diabetic and 29.3% had Type 2 Diabetes Mellitus. Chest radiography was normal in 56.0% of patients, while cardiomegaly (26.7%) and pleural effusion (14.7%) were the most common abnormal findings. Patients with left ventricular hypertrophy demonstrated significantly higher mean NT-proBNP levels than those without LVH (1398.54±806.32 pg/ml vs. 642.81±724.18 pg/ml; p<0.001). No statistically significant difference in NT-proBNP levels was observed between males and females (p=0.479). Patients with systemic hypertension had significantly higher NT-proBNP levels compared to normotensive patients (p=0.002). Similarly, smokers exhibited significantly elevated NT-proBNP levels compared to non-smokers (p=0.003), indicating a strong association between NT-proBNP concentration and important cardiovascular risk factors. Conclusion: Serum NT-proBNP is a reliable and clinically useful biomarker for the diagnosis of diastolic heart failure and demonstrates a significant correlation with echocardiographic findings. Elevated NT-proBNP levels are strongly associated with left ventricular hypertrophy, systemic hypertension, and smoking, supporting its role as a non-invasive adjunct to echocardiography for early diagnosis, disease severity assessment, and risk stratification in patients with diastolic heart failure.