Biomarkers and Peak Oxygen Uptake in Patients with Chronic Lung Disease.

Background: Peak oxygen uptake (peak VO₂) is a predictor of outcome in patients with lung disease. In these patients, peak VO₂ is typically determined by ventilation and gas exchange. However, it is not well known whether cardiac strain contributes to peak VO₂ in patients with chronic lung disease. Objective: To assess the relationship between several novel biomarkers reflecting different aspects of cardiac function and peak VO₂ in patients with chronic lung disease. Methods: Plasma concentrations of midregional pro-A-type natriuret- ic peptide (MR-proANP), midregional proadrenomedullin (MR-proADM), C-terminal proendothelin-1 (CT-proET-1), and C-terminal provasopressin (copeptin) were measured in 85 patients with a variety of chronic pulmonary diseases [age 57 ± 14 years, forced expiratory volume in the 1st second (FEV₁) 76 ± 23% of the predicted value] undergoing maximal cardiopulmonary exercise testing (peak VO₂ 18.6 ± 6.6 ml/kg/min). Results: Raised MR-proANP (r = -0.54), MR- proADM (r = -0.54), and CT-proET-1 (r = -0.49; p < 0.001 for all) but not copeptin (r = -0.05; p = 0.68) concentrations were associated with lower peak VO₂, and these associations were independent of age, gender, medication, FEV₁ and oxygenation. The relationship between MR-proANP, MR-proADM, and CT-proET-1 and peak VO₂ was significant whether patients had an obstructive ventilatory disease or not. Conclusions: In patients with chronic lung disease, several biomarkers known to reflect measures of cardiac function were associated with peak VO₂ independent of lung function, indicating that cardiac strain may contribute to exercise limitation in these patients due to concomitant cardiac disease or in the context of a pulmonary-cardiac interaction. Copyright © 2010 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]