PURPOSE: Recognising heart disease is relevant to pulmonologists because many patients suspected to have dyspnea of pulmonary origin harbor heart disease. This study investigated the role of NT-proBNP in identifying a wide range of cardiac disorders.
METHODS: The study group comprised 697 consecutive outpatients (57.5±16.4 years) referred to a hospital-based pulmonology service for evaluation of dyspnea. The cardiological findings were pooled in the 5 predefined characteristic groups mentioned below.
RESULTS: Prevalence of left ventricular systolic dysfunction was only 4.3%. After adjusting for age, sex and body mass index by multiple linear regression, all 5 characteristic groups were associated with an increase in NT-proBNP in the following order: (5) left ventricular systolic dysfunction (regression coefficient [β]=1.90, p<0.0001), (4) atrial fibrillation, left bundle branch block or exercise-induced myocardial ischemia (β=1.17, p<0.0001), (3) pulmonary hypertension (β=1.17, p<0.0001), (2) valvular or congenital heart disease or pericardial effusion (β=0.93, p<0.0001), and (1) left ventricular hypertrophy (β=0.33, p=0.03)]. Pulmonary dysfunction had no effect on NT-proBNP. Using NT-proBNP cut-off values of 93 pg/ml (men) and 144 pg/ml (women), sensitivity was 96.7% and specificity was 68.2% when left ventricular systolic dysfunction was required for the diagnosis of heart disease. The positive predictive values increased from 12.0% to over 50% with more inclusive definitions of heart disease without the negative predictive values falling below 90%.
CONCLUSION: NT-proBNP is not only an almost perfect rule-out test for systolic heart failure but also a global marker of heart disease. An elevated NT-proBNP often identifies cardiac disorders other than systolic dysfunction that can contribute to dyspnea and may be precursors of overt heart failure.
CLINICAL IMPLICATIONS: NT-proBNP helps the pulmonologist to appropriately select candidates for cardiological evaluation. If the pulmonologist proceeds with cardiologic evaluation at a NT-proBNP above 93 pg/ml in men and 144 pg/ml in women aged ≥65 years, the cardiologist would identify left ventricular systolic dysfunction in 1 out of 5 cases and at least 1 finding of the cardiological characteristic groups 1–5 in 5 out of 7 cases.
DISCLOSURE: Siegfried Wieshammer, No Financial Disclosure Information; No Product/Research Disclosure Information