Progression of mean pulmonary arterial pressure in idiopathic pulmonary fibrosis with mild to moderate restriction

Background and objectiveElevation of mean pulmonary arterial pressure (MPAP) is associated with poor prognosis in patients with idiopathic pulmonary fibrosis (IPF), yet the progression of MPAP in patients with IPF has not been sufficiently elucidated. We evaluated serial changes in MPAP and its determinants in patients with IPF with mild to moderate restriction. MethodsWe retrospectively reviewed patients with IPF who underwent initial evaluations including right heart catheterization (RHC) in our institute from May 2007 to December 2013 with follow-up RHC at least 1year later. Patients with forced vital capacity (FVC)<50% predicted or those with pulmonary artery wedge pressure>15mm Hg were excluded. ResultsA total of 95 patients were included. Median follow-up time of second RHC was 1.8years. MPAP increased significantly at follow-up (from 16.8 to 20.2mm Hg; P<0.001), and annual change in MPAP (MPAP) was 1.8mm Hg/year. In multiple regression analysis, the lowest oxygen saturation (SpO(2) ) at 6-min walk test (6MWT) was an independent predictor of MPAP. When adjusted for age, sex, baseline MPAP and FVC % predicted, MPAP was a significant predictor of mortality (hazard ratio: 1.21; P=0.001). ConclusionMPAP was significantly associated with desaturation in the 6MWT, and with increased mortality in patients with IPF with mild to moderate restriction. We reviewed patients with idiopathic pulmonary fibrosis with mild to moderate restriction and showed that mean pulmonary arterial pressure (MPAP) was progressive. The lowest oxygen saturation (SpO(2) ) in the 6-min walk test at baseline was an independent predictor of annual change in MPAP.