Responses to exercise in systemic sclerosis‐associated interstitial lung disease

• Published in: Clinical physiology and functional imaging Vol. 43; no. 4; pp. 253 - 262
• Main Authors: Donnelly, Ronan P., Smyth, Anita E., Mullan, Charles, Riley, Marshall S., Nicholls, D. Paul
• Format: Journal Article
• Language: English
• Published: England Wiley Subscription Services, Inc 01.07.2023
• Subjects: Abnormalities; Alveoli; Atrial natriuretic peptide; Blood; Carbon dioxide; exercise test; Exercise Test - methods; Gas exchange; Gas sampling; Humans; Hypertension, Pulmonary; Lung; Lung diseases; Lung Diseases, Interstitial - complications; Lung Diseases, Interstitial - etiology; Morbidity; neurohumoral responses; Neurotransmitters; Oxygen consumption; pulmonary fibrosis; Pulmonary functions; pulmonary gas exchange; Respiratory function; Scleroderma; Scleroderma, Systemic - complications; Scleroderma, Systemic - diagnosis; Systemic sclerosis; neurohumoral responses; exercise test; scleroderma; pulmonary fibrosis; pulmonary gas exchange
• ISSN: 1475-0961; 1475-097X; 1475-097X
• DOI: 10.1111/cpf.12813

Introduction Pulmonary complications in systemic sclerosis (SSc) significantly increase morbidity and mortality. Our aim was to determine the factors limiting exercise capacity in SSc patients with and without interstitial lung disease (ILD), and to identify and quantify abnormalities during exercise that might assist in clinical assessment of this complication. Methods Fifteen patients with SSc and ILD (SSc‐ILD) were compared with 10 patients with SSc without ILD and 9 age‐ and sex‐matched normal volunteers. Subjects performed symptom‐limited incremental treadmill exercise with online measurement of respiratory gas exchange, arterial blood gas sampling and measurement of neurohormones in venous blood. Results Patients with SSc‐ILD had lower exercise capacity than SSc patients without ILD or normal subjects (peak oxygen consumption (PV̇O2) (17.1 [4.2] vs. 22.0 [4.7] and 23.0 [5.4] ml kg−1 min−1, respectively, mean [SD], p < 0.01 ANOVA), but PV̇O2 did not correlate with static pulmonary function measurements. Ventilatory equivalent for CO2 (V̇E/V̇CO2; nadir) was higher in SSc‐ILD patients than the other two groups (36.6 [8.0] vs. 29.9 [4.4] and 30.0 [2.5], p < 0.005) as were peak exercise dead‐space tidal volume ratio (0.44 [0.06] vs. 0.26 [0.09] and 0.26 [0.05], p < 0.001) and peak exercise alveolar–arterial difference (28.9 [16.9] vs. 18.8 [14.0] and 11.5 [6.9] mmHg, p < 0.05). Atrial natriuretic peptide was elevated in both SSc patient groups. Conclusions SSc‐ILD results in lower exercise capacity than SSc without ILD, and abnormalities of gas exchange are seen. The possible use of cardiopulmonary exercise testing to identify disease and quantify impairment in SSc‐ILD merits further study.