Acute exacerbations and pulmonary hypertension in advanced idiopathic pulmonary fibrosis

The aim of this study was to evaluate the risk factors for and outcomes of acute exacerbations in patients with advanced idiopathic pulmonary fibrosis (IPF), and to examine the relationship between disease severity and neovascularisation in explanted IPF lung tissue. 55 IPF patients assessed for lung transplantation were divided into acute (n=27) and non-acute exacerbation (n=28) groups. Haemodynamic data was collected at baseline, at the time of acute exacerbation and at lung transplantation. Histological analysis and CD31 immunostaining to quantify microvessel density (MVD) was performed on the explanted lung tissue of 13 transplanted patients. Acute exacerbations were associated with increased mortality (p=0.0015). Pulmonary hypertension (PH) at baseline and acute exacerbations were associated with poor survival (p<0.01). PH at baseline was associated with a significant risk of acute exacerbations (HR 2.217, p=0.041). Neovascularisation (MVD) was significantly increased in areas of cellular fibrosis and significantly decreased in areas of honeycombing. There was a significant inverse correlation between mean pulmonary artery pressure and MVD in areas of honeycombing. Acute exacerbations were associated with significantly increased mortality in patients with advanced IPF. PH was associated with the subsequent development of an acute exacerbation and with poor survival. Neovascularisation was significantly decreased in areas of honeycombing, and was significantly inversely correlated with mean pulmonary arterial pressure in areas of honeycombing.