NT-proBNP: a marker of preclinical cardiac damage in arterial hypertension.

Background: The cardiac left ventricle responds to pressure overloads with mechanisms culminating in irreversible structural/functional cardiac alterations (left ventricular hypertrophy and/or diastolic dysfunction), inducing myocardial cells to secrete natriuretic peptides (NT-proBNP) antagonists of the renin-angiotensin-aldosterone system. The aim of this study was to evaluate the diagnostic accuracy of serum NT-proBNP levels in order to detect structural/functional cardiac diseases assessed by echocardiography.

Methods: A total of 126 consecutive newly diagnosed, never before treated, hypertensive patients (30-67 years) were enrolled, and clinical, echocardiography parameters and biochemical data were collected. Our reference was the presence of structural/functional cardiac disease (CSFD) and our index text was the serum NT-proBNP levels.

Results: NT-proBNP levels in CSFD patients were ~2 times higher than in non-CSFD subjects (median 61 vs 29 ng/L, n=50 and 76, respectively); in addition, 60% of CSFD subjects (only 14% of which with pathological levels, >125 ng/L), and 30% without CSFD showed NT-proBNP concentrations higher than 50 ng/L. However, ROC curves demonstrated a low specificity (38%) (calculated at 90% sensitivity at a cut-off of 22.5 ng/L).

Discussion: NT-proBNP levels, as a screening tool for cardiac structural/functional disease, appear to be limited, because of the low specificity. However, the strong association between its concentration and the establishment of irreversible cardiac hypertrophy prompts successive studies aimed to ascertain the use of its serum levels as an early alert indicator of disease severity.