Low DLCO in idiopathic pulmonary arterial hypertension - clinical correlates and prognostic significance

Abstract

INTRODUCTION: Decreased diffusing capacity of the lung for carbon monoxide (DLCO) is observed in some idiopathic pulmonary arterial hypertension (IPAH) patients, but its clinical significance is uncertain. We aimed to assess clinical correlates and prognostic significance of low DLCO in IPAH patients. MATERIAL AND METHODS: In the group of 65 IPAH patients the cut off value for low DLCO was set up based on histogram as < 55% of predicted value. Demographic data, exercise capacity, lung function tests, hemodynamic parameters and survival of the patients were compared depending on DLCO value. RESULTS: Low DLCO was found in 18% of the patients, and it was associated with male sex, older age, worse functional status and exercise capacity, and higher prevalence of coronary artery disease. Low DLCO carried a 4-fold increase of death risk in 5-year perspective. CONCLUSIONS: Low DLCO was a marker of worse functional capacity and increased risk of death in studied IPAH patients.