The interrelationship between usual interstitial Pneumonia, pulmonary hypertension and pulmonary vascular remodelling

Abstract

Aims To determine whether vascular remodelling differs between fibrotic and non-fibrotic lung in usual interstitial pneumonia (UIP) and whether this correlates with pulmonary hypertension (PH). Methods External diameter, media and intima were measured in muscular arteries ( n = 4) was used for comparison. Results Increases 0.64-fold ( p 0.0001) and 6.50-fold ( p 0.0001) in medial and intimal thickening were determined in fibrotic versus non-fibrotic lung in UIP. Increases 0.63-fold ( p = 0.0032) and 5.47-fold ( p 0.0001) in medial and intimal thickening were found in UIP with PH. Increases 1.20-fold ( p = 0.00055) and 1.50-fold (p = 0.0041) in intimal thickening were determined between non-fibrotic lung in UIP and controls, and in a subset of cases with PH and controls, respectively. A linear correlation was determined between systolic pulmonary artery pressure PAP and intima in fibrotic lung in UIP [r(23) = 0.569, p = 0.0030]. Discussion Vascular remodelling was found in fibrotic lung in UIP and in UIP-associated PH, and a linear correlation was found between vascular remodelling and PH in UIP. A lesser extent of vascular remodelling was determined in non-fibrotic lung, indicating that fibrosis is critical to pulmonary vascular remodelling.