Diagnostic usefulness of NT-proBNP in asymptomatic left ventricular dysunction in black hypertensive patients

Abstract

Background: Hypertensive patients with left ventricular (LV) dysfunction, may be asymptomatic early in the disease process but tend to develop overt heart failure later on. While the usefulness of NT-proBNP in the early detection of LV dysfunction has been well studied among the Western population, there remains a relative paucity of information about its usefulness among black hypertensive patients. The aim of this study was to determine the diagnostic usefulness of NT-proBNP in the early detection of asymptomatic LV dysfunction in black hypertensive patients. Methodology: The LV function of 134 patients with hypertension who were never in heart failure and 89 age- and sex-matched normotensive individuals were assessed using echocardiography and serum NT-proBNP assay. However, due to various factors (such as drop out and abnormal laboratory results), 131 hypertensives and 79 controls were eventually analyzed. Echocardiography was used as gold standard in determining LV functions. NT-proBNP levels were measured using enzyme-linked immunosorbent assay. Data obtained were summarized with appropriate descriptive and inferential statistics at a 5% level of significance using the Statistical Package for the Social Science (SPSS) Version 22.0 software. Results: Asymptomatic LV dysfunction was present in 107 hypertensive individuals (81.7%): 102 (77.9%) had isolated diastolic dysfunction and 5 (3.8%) had combined diastolic and systolic dysfunction; whereas the remaining 24 patients (18.3%) had normal LV function. NT-proBNP were 175.21 ± 227.75 and 430.13 ± 491.88 pg/ml, P = 0.017, in hypertensive individuals without and with asymptomatic LV dysfunction, respectively. Using the NT-proBNP level of 56 pg/ml obtained among the controls, NT-proBNP level had a sensitivity of 62.8% and specificity of 60.9%. NT-proBNP level also had a positive predictive value of 88.0% and negative predictive value of 26.4%. Conclusion: NT-pro-BNP could be incorporated as a screening tool for early detection of asymptomatic LV dysfunction and possibly, stratify patients for further evaluation and treatment.