Sarcoidosis - The value of exercise testing

Study objectives: To evaluate exercise testing for the assessment of the ex tent of pulmonary disease in patients with sarcoidosis, Design: Retrospective analysis of consecutive patients with sarcoidosis ref erred to the Pulmonary Physiology Laboratory between 1992 and 1997, who com pleted at least 6 min of progressive bicycle exercise. Resting and exercise pulmonary function measurements were compared to radiographic stage of dis ease. Setting: Pulmonary Physiology Laboratory at Washington, DC, Veterans Affair s Medical Center. Patients: Forty-eight outpatient veterans with biopsy specimen-proven sarco idosis. Results: Across all radiographic stages of sarcoidosis, total lung capacity , resting diffusing capacity, and exercise gas exchange measurements had a significant variance with radiographic stage. Across the early radiographic stage disease (stages 0 to 2), the change in alveolar-arterial oxygen pres sure gradient between rest;md exercise, normalized for oxygen uptake, was t he most significant measurement in its variation with radiographic stage. Conclusions: Changes in gas exchange with exercise may be the most sensitiv e physiologic measurements to assess the extent of disease in early radiogr aphic stages of sarcoidosis.