Evaluation of N-Terminal Pro-Brain Natriuretic Peptide as A Diagnostic Marker in Acute Heart Failure
Background: The rapid and accurate differentiation of heart failure from other causes of dyspnea remains a clinical challenge in the emergency setting. The present work aimed at evaluating the role of N-terminal probrain natriuretic peptide (NTproBNP) as a marker for diagnosis or ruling out of acute ventricular heart failure
Patients and methods: forty male patients presented with symptoms and signs of acute heart failure were recruited. They were in their first presentation or were acute cases on top of chronic heart failure. Blood samples were taken twice from each patient; once on admission day and five days later after receiving treatment. Twenty healthy matched adult males were recruited as controls. NTproBNP was quantitatively assayed using competitive enzyme linked immunosorbant assay.
Results: The median level of NTproBNP showed a statistically significant difference between the patients whether before or after treatment and the controls P(<0.001) and between the two subgroups of patients before and after treatment where the median level of NT-proBNP was markedly decreased in patients after treatment (<0.001). The median level of NTproBNP showed a statistically significant difference between the functional classes of heart failure as categorized by echocardiogram both before and after treatment; where cases with normal echocardiographic findings showed marked reduction with statistical significant difference P(<0.001) while cases with abnormal echocardiographic findings showed more marked reduction in level with statistically significant difference P(<0.001) .The receiver operating characteristic (ROC) curve at a cut off level of 147.7 fmol/ml of NTproBNP before treatment showed a sensitivity of 100% and a specificity of 80%;Positive predictive value of 93.8; negative predictive value of 100 ; accuracy of 95% with area under the curve (AUC)of 5,while the level of NTproBNP after treatment at the same cut off level showed marked reduction in sensitivity of 46.7% and a
specificity was 80% Positive predictive value of 87.5; negative predictive value of 87.5 ; accuracy of 55 % with area under the curve (AUC)of 2.3. Conclusions:Measurement of NTproBNP in subjects presented with dyspnea and other signs of heart failure to the emergency department; may provide a reliable diagnostic laboratory tool for diagnosis of heart failure. The number of echo needed and the cost of screening can hence be reduced. NTproBNP marker could be used in acute heart failure cases when firsly presented but not previously treated.
Key words: NTproBNP: N terminal pro brain natriuretic peptide , ROC curve : receiver operating characteristic , AUC : area under the curve , HF : Heart failure , COPD : chronic obstructive pulmonary disease.