SUPERIORITY OF BRAIN NATRIURETIC PEPTIDE AS A HORMONAL MARKER OF VENTRICULAR SYSTOLIC AND DIASTOLIC DYSFUNCTION AND VENTRICULAR HYPERTROPHY

Atrial and brain natriuretic peptides (ANP and BNP) are produced by th e heart, and their plasma concentrations are increased in human chroni c congestive heart failure. Although separate studies have suggested t hat circulating levels of the biologically active C-terminal ANP, the biologically inactive N-terminal ANP, and BNP may have diagnostic util ity in the detection of left ventricular systolic dysfunction or left ventricular hypertrophy, no studies have directly assessed the relativ e value of these peptides prospectively. We therefore designed this st udy to compare the relative ability of the different natriuretic pepti des to detect abnormal left ventricular systolic and diastolic functio n and left ventricular hypertrophy. Using a prospective study design, we investigated 94 patients referred for cardiac catheterization and 1 5 age-matched normal subjects. The diagnostic abilities of elevated pl asma C-terminal ANP, N-terminal ANP(1-30), and BNP concentrations to i dentify systolic dysfunction !ejection fraction <45%), diastolic dysfu nction (time constant of left ventricular relaxation >55 milliseconds, left ventricular end-diastolic pressure > 18 mm Hg), and left ventric ular hypertrophy (left ventricular mass index >120 g/m(2)) were object ively com pared by receiver operating characteristic analysis. The are as under the receiver operating characteristic curve of BNP for detect ing each of these abnormalities ranged from 0.715 to 0.908 and were si gnificantly greater than those of C-terminal ANP or N-terminal ANP-(1- 30). The sensitivity and specificity of an elevated plasma BNP, which we defined as greater than the mean + 3 SD of the 15 age-matched norma l subjects, were 0.83 and 0.77, respectively, for detecting ejection f raction less than 45%, 0.85 and 0.70 for detecting the time constant o f left ventricular relaxation greater than 55 milliseconds, 0.63 and 0 .76 for detecting left ventricular end-diastolic pressure greater than 18 mm Hg, and 0.81 and 0.85 for detecting left ventricular mass index greater than 120 g/m(2). The use of BNP and one other peptide increas ed sensitivity (0.80 to 0.96), albeit with lower specificity (0.56 to 0.71). An elevated plasma BNP was a more powerful marker of left ventr icular systolic dysfunction, left ventricular diastolic dysfunction, a nd left ventricular hypertrophy than C-terminal ANP or N-terminal ANP- (1-30) in this population of patients with suspected cardiac disease. Measurement of BNP alone or in combination with C-terminal ANP or N-te rminal ANP-(1-30) has potential utility for the detection of altered l eft ventricular structure and function in a patient population at risk for cardiovascular disease.