Pulmonary function testing in patients with pulmonary arterial hypertension
Received 22 November 2008; accepted 2 March 2009. published online 29 April 2009.
Summary
Background
Although previous studies have shown that peripheral airway obstruction can occur in idiopathic PAH (IPAH), pulmonary function tests have not been well-studied in patients with PAH associated with congenital heart disease (CHD-PAH) and connective tissue disease (CTD-PAH).
Methods
A multicenter prospective study was performed in PAH patients in China. Pulmonary function tests were evaluated in 190 PAH patients.
Results
Total lung capacity (TLC), residual volume (RV) and total airway resistance (Rtot) were similar in PAH patients and controls. However, measures of airflow, including vital capacity (VC), forced vital capacity (FVC), forced expiratory volume in 1s (FEV1), FEV1/FVC and MEF50 were decreased in PAH group. Single-breath diffusion capacity for carbon monoxide (DLCO) was also decreased in PAH patients. Expiratory flow–volume curves showed reduction and a curvilinear appearance in patients with PAH. Similar changes were observed among the various subgroups of IPAH, CHD-PAH, and CTD-PAH patients. More CTD-PAH patients had abnormal DLCO.
Conclusions
Airway obstruction is common in IPAH, CHD-PAH and CTD-PAH patients. CTD-PAH patients have lower DLCO. Hemodynamics, serum markers and exercise capacity parameters did not correlate well with pulmonary function indices.
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