The role of N terminal pro-brain natriuretic peptide in the evaluation of left ventricular diastolic dysfunction: correlation with echocardiographic indexes in hypertensive patients

Abstract

The utility of N-Terminal pro Brain Natriuretic Peptide (NT-proBNP) and Brain Natriuretic Peptide (BNP) for detecting left ventricular (LV) diastolic dysfunction in hypertensive patients without heart failure symptoms is unclear. In this study, we investigated the relation between NT-proBNP plasma levels and LV diastolic dysfunction in hypertensive patients without systolic dysfunction. We studied 40 ambulatory patients (26 women, mean age 52 +/- 5) with controlled hypertension. LV diastolic function was assessed with conventional Doppler, by means of mitral inflow and with tissue Doppler echocardiography by means of mitral annulus. The ratio of early diastolic transmitral E wave velocities to tissue Doppler mitral annulus early diastolic E' wave velocities (E/E'), was used to detect LV filling pressures. Patients were divided in three groups according to E/E' ratios < 10 (group I), E/E' ratios ''between'' 10 and 15 (group II) and E/E' ratios > 15 (group III). Plasma concentrations of NT-proBNP were measured by electro chemiluminescence's immunoassay. The NT-proBNP blood levels were positively correlated significantly with E/E' ratio (r = 0.80, P < 0.0001). Patients with elevated LV end diastolic pressure (LVEDP), defined as E/E' > 15 (n = 8) had highest NT-proBNP (203 +/- 75 pg/ml) levels. E/E' 10 to 15 group (n = 16) had a mean NT-proBNP level of 71 +/- 26 pg/ml, and those with E/E' < 10 (n = 16) had 39 +/- 20 pg/ml. A NT-proBNP value of 119 pg/ml had a sensitivity of 87%, a specificity of 100% for predicting E/E' > 15. The assessment of the blood concentration of NT-proBNP is of potential value for identification of those patients with hypertension to detect early cardiovascular changes, especially LV diastolic dysfunction.