NT-proBNP for pulmonologists: not only a rule-out test for systolic heart failure but also a global marker of heart disease.

BACKGROUND

Recognizing heart disease is relevant to pulmonologists because many patients suspected to have dyspnea of pulmonary origin harbor heart disease.

OBJECTIVES

To investigate the role of N-terminal pro-brain natriuretric peptide (NT-proBNP) in identifying heart disease and cardiac causes of dyspnea among patients referred for evaluation by a pulmonologist.

METHODS

697 consecutive outpatients (aged 57.5 +/- 16.4 years) with chronic dyspnea prospectively underwent a diagnostic work-up for heart and lung diseases.

RESULTS

The prevalence of patients with heart disease was 25.3%. The cardiac findings were placed into 6 groups which were associated with an increase in NT-proBNP in the following order: (1) left ventricular hypertrophy [regression coefficient (beta) = 0.33, p = 0.03]; (2) exercise-induced myocardial ischemia (beta = 0.73, p = 0.02);(3) valvular or congenital heart disease or pericardial effusion (beta = 0.93, p < 0.0001); (4) pulmonary hypertension (beta = 1.14, p < 0.0001); (5) atrial fibrillation or left bundle branch block (beta = 1.22, p < 0.0001), and (6) left ventricular systolic dysfunction (beta = 1.94, p < 0.0001). Using predefined cut-off values of 93 pg/ml (men) and 144 pg/ml (women), sensitivity was 0.75 and specificity was 0.79 for identifying heart disease. The negative predictive value was 0.90. If heart disease had to be considered as a cause of the dyspnea, sensitivity and the negative predictive value went up to 0.90 and 0.97, respectively.

CONCLUSIONS

NT-proBNP performs well as a test for ruling out cardiac dyspnea. It is also useful as a rule-in test for heart disease, which enables the pulmonologist to appropriately select candidates for in-depth evaluation by cardiology.