Objective: To determine the diagnostic value of pulmonary function testing in Chinese patients with known pulmonary arterial hypertension (PAH) without history of lung/heart valve diseases.
Methods: Pulmonary function testing was performed in 41 PAH patients diagnosed by right heart catheterization and in 17 healthy controls.
Results: Normal pulmonary function testing results were found in 5 PAH patients (12.2%). Total lung capacity, vital capacity and FEV1 were significantly decreased in PAH patients [(80.27 +/- 11.46)% vs. (94.24 +/- 6.82)%; (79.09 +/- 14.89)% vs. (97.35 +/- 9.51)%; (75.40 +/- 16.58)% vs. (95.12 +/- 12.01)%, respectively, all P < 0.001], the ratio of residual volume/total lung capacity was significantly increased [(117.67 +/- 25.73)% vs. (93.39 +/- 10.87)%, P < 0.001]; FEV1/FVC and maximal expiratory flow of 25% to 75% tended to be lower (-6.0% and -19.4%, P = 0.21 and 0.09) while DLCO and DLCO/VA were significantly decreased by 36.6% and 29.8% (P < 0.001) compared with healthy controls.
Conclusions: Increased peripheral airway obstruction and normal lung resistance were found in these PAH patients. Normal pulmonary function testing results could not rule out the diagnosis of PAH.