N-terminal Pro Brain Natriuretic Peptide (NT-proBNP) as a Marker for Risk Stratification and Prediction of Functional Outcome in Acute Ischaemic Stroke

Abstract

Introduction: Stroke is the second leading cause of mortality and disability worldwide. A large proportion of stroke survivors are left with significant disability. Assessing stroke severity and predicting morbidity and mortality is essential for treatment decisions and counseling. Traditionally used tools like the National Institutes of Health Stroke Scale (NIHSS) are not reliable in predicting mortality. Studies have shown that B-type Natriuretic Peptide (BNP) and N-terminal pro Brain Natriuretic Peptide (NT-proBNP) are elevated in acute stroke. Aim: To assess the prognostic importance of NT-proBNP in stroke. Materials and Methods: A prospective cohort study was conducted at Sri Devaraj URS Medical College (SDUMC), SDUAHER, Kolar, Karnataka, India involving 64 consecutive stroke patients from July 2018 to September 2019. Serum NTproBNP levels were measured on both the day of admission and on day 7. Stroke severity was assessed using the NIHSS on admission day, and functional disability was determined using the Barthel Index (BI) at the 3-month mark. Data were entered into MS Excel for statistical analysis, where a p-value of <0.05 was considered statistically significant. Results: The average age of the subjects was 62.36 years with a standard deviation of 12.15 years. The average NIHSS on the day of admission was 12.81 (7), and it was 20.2 (5.882) among deceased patients. The mean NT-proBNP on admission was 776.70 (1023.6) pg/mL, significantly elevated in deceased patients at 2014.65 (1320.546) compared to survivors at 328.94 (239.353). NT-proBNP is strongly associated with stroke severity (NIHSS) (R2=0.522; Spearman’s correlation coefficient=0.843, p-value <0.001) and functional outcome (BI) (R2=0.824; Spearman’s correlation coefficient -0.923, p-value <0.001) at three months.On Receiver Operating Characteristic (ROC) analysis, a serum NT-proBNP level of 960 pg/mL had a sensitivity and specificity of 94.1% and 97.9% in predicting mortality, and a value of 435.1 pg/mL had a sensitivity and specificity of 90% and 81% in predicting disability. Conclusion: Serum NT-proBNP was significantly elevated in patients after stroke and was strongly associated with stroke severity and functional outcome at three months. Measuring serum NT-proBNP on the day of admission can predict mortality and functional dependence after acute ischaemic stroke.