Received on June 23, 2005
Accepted on September 23, 2005

Proteomics and Protein Markers

Capability of B-Type Natriuretic Peptide (BNP) and Amino-Terminal proBNP as Indicators of Cardiac Structural Disease in Asymptomatic Patients with Systemic Arterial Hypertension

¹ Departments of Laboratory Medicine and Internal Medicine, Konventhospital Barmherzige Brueder, Linz, Austria, and Laboratory Medicine
² Departments of Laboratory Medicine and Internal Medicine, Konventhospital Barmherzige Brueder, Linz, Austria, and Internal Medicine, Konventhospital Barmherzige Brueder, Linz, Austria
³ Departments of Laboratory Medicine and Internal Medicine, Konventhospital Barmherzige Brueder, Linz, Austria, and Institute for Applied System Sciences and Statistics, University of Linz, Linz, Austria

^* To whom correspondence should be addressed. E-mail: thomas.mueller{at}bblinz.at.

Background: The aim of the present study was to prospectively evaluate the diagnostic utility of B-type natriuretic peptide (BNP) and amino-terminal proBNP (NT-proBNP) measurements for the detection of cardiac structural disease in asymptomatic patients with systemic arterial hypertension and to test the hypothesis that the 2 analytes are equally useful in this clinical setting.

Methods: A consecutive series of 149 asymptomatic patients referred for echocardiographic evaluation of the cardiac effects of systemic arterial hypertension were studied. Diagnosis of cardiac structural disease was based on the presence of systolic or diastolic dysfunction, left atrial dilatation, left ventricular dilatation or hypertrophy, pulmonary hypertension, and wall motion or valvular abnormalities. Blood concentrations of BNP and NT-proBNP were measured by 2 commercially available assays (Abbott AxSYM and Roche Elecsys, respectively). Diagnostic accuracies of BNP and NT-proBNP were assessed by ROC curve analysis. Areas under the curve were compared by analysis of equivalency.

Results: In distinguishing between hypertensive patients with cardiac structural disease (n = 118) and hypertensive patients without (n = 31), areas under the curves were 0.740 (95% confidence interval, 0.662-0.808) for BNP and 0.762 (0.685-0.828) for NT-proBNP and were significantly equivalent (P = 0.015). Cutoff values with a 90% sensitivity for cardiac structural disease were 17 ng/L for BNP and 39 ng/L for NT-proBNP, with 29% and a 32% specificity, respectively.

Conclusions: BNP and NT-proBNP have similar capabilities for the detection of cardiac structural disease in asymptomatic patients with systemic arterial hypertension. However, in the setting evaluated, a screening strategy measuring BNP or NT-proBNP may be of limited value because of the low specificity at the selected cutoff values.