Discriminating between cardiac and pulmonary dysfunction in the general population with dyspnea by plasma pro-B-type natriuretic peptide.

OBJECTIVES This study was designed to determine whether measurement of plasma pro-B-type natriuretic peptide (proBNP) could be used in discriminating between cardiac and pulmonary dyspnea in the general population. BACKGROUND Natriuretic peptides are useful markers in ruling out acute cardiac dyspnea in the emergency department, but their diagnostic significance in evaluating chronic dyspnea in the general population is unknown. METHODS Within the Copenhagen City Heart Study, a large, community-based population study, dyspnea was evaluated by spirometry, oxygen saturation, echocardiography, and plasma proBNP. RESULTS Of 2,929 participants, 959 reported dyspnea. The plasma proBNP concentration was higher in the group with dyspnea (mean 17.8 pmol/l; 95% confidence interval [CI] 16.3 to 19.4 pmol/l) than in the group without (10.6 pmol/l; 95% CI 10.0 to 11.4 pmol/l; p < 0.001). In the group with dyspnea, left ventricular hypertrophy and/or systolic dysfunction was associated with a 2.6-fold increase in plasma proBNP concentration (p < 0.001), whereas pulmonary dysfunction was not associated with increased plasma proBNP (p = 0.66). Using multivariable regression analysis, a model to estimate the expected concentration of plasma proBNP based on age and gender was established for dyspneic subjects: an actual plasma proBNP concentration below half of the expected value ruled out left ventricular systolic and diastolic dysfunction (sensitivity 100%, 95% CI 100% to 100%; specificity 15%, 95% CI 12% to 17%). CONCLUSIONS In the general population with dyspnea, plasma proBNP concentrations are increased in left ventricular dilatation, hypertrophy, systolic dysfunction, or diastolic dysfunction, but are unaffected by pulmonary dysfunction.