Sarcoidosis: the value of exercise testing.

STUDY OBJECTIVES

To evaluate exercise testing for the assessment of the extent of pulmonary disease in patients with sarcoidosis.

DESIGN

Retrospective analysis of consecutive patients with sarcoidosis referred to the Pulmonary Physiology Laboratory between 1992 and 1997, who completed at least 6 min of progressive bicycle exercise. Resting and exercise pulmonary function measurements were compared to radiographic stage of disease.

SETTING

Pulmonary Physiology Laboratory at Washington, DC, Veterans Affairs Medical Center.

PATIENTS

Forty-eight outpatient veterans with biopsy specimen-proven sarcoidosis.

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 pressure gradient between rest and exercise, normalized for oxygen uptake, was the most significant measurement in its variation with radiographic stage.

CONCLUSIONS

Changes in gas exchange with exercise may be the most sensitive physiologic measurements to assess the extent of disease in early radiographic stages of sarcoidosis.