Noninvasive tests for the diagnostic evaluation of dyspnea among outpatients: The multi-ethnic study of atherosclerosis lung study

BACKGROUND: Dyspnea on exertion is a common and debilitating symptom, yet evidence for the relative value of cardiac and pulmonary tests for the evaluation of chronic dyspnea among adults without known cardiac or pulmonary disease is limited. METHODS: The Multi-Ethnic Study of Atherosclerosis (MESA) enrolled participants aged 45 to 84 years who were free of clinical cardiovascular disease from 6 communities; participants with clinical pulmonary disease were excluded from this report. Dyspnea on exertion was assessed via structured interview. Tests included electrocardiograms, cardiac computed tomography (CT) for coronary artery calcium, cardiac magnetic resonance imaging, spirometry, percent emphysema (percent of lung regions <-950 HU) on CT, inflammatory biomarkers, and N-terminal pro-brain natriuretic peptide (NT-proBNP). Logistic regression was used to identify independent correlates of dyspnea after adjustment for age, sex, body mass index, physical activity, anxiety, and leg pain. RESULTS: Among 1969 participants without known cardiopulmonary disease, 9% had dyspnea. The forced expiratory volume in 1 second (FEV₁) (P <.001), NT-proBNP (P =.004), and percent emphysema on CT (P =.004) provided independent information on the probability of self-reported dyspnea. Associations with the FEV₁ were stronger among smokers and participants with other recent respiratory symptoms or seasonal allergies; associations with NT-proBNP were present only among participants with coexisting symptoms of lower-extremity edema. Only the FEV₁ provided a significant improvement in the receiver operating curve. CONCLUSIONS: Among adults without known cardiac or pulmonary disease reporting dyspnea on exertion, spirometry, NT-proBNP, and CT imaging for pulmonary parenchymal disease were the most informative tests.