Pulmonary hypertension in interstitial lung disease

In the lungs, parenchymal and vascular remodelling share pathomechanisms that may explain the relatively high prevalence (30-40%) of pulmonary hypertension (PH) in interstitial lung disease (ILD) patients. Notably, PH significantly contributes to exercise limitation and dismal prognosis of ILD patients. The absence of specific clinical symptoms commonly leads to delayed diagnosis. Besides clinical judgment and out-of-proportion reduction in diffusing capacity, severe hypoxaemia or exercise oxygen desaturation, echocardiography and biomarkers such as B-type natriuretic peptide (BNP) and N-terminal pro-hormone BNP are potentially helpful tools in identifying PH. However, right heart catheterisation is still necessary to confirm the diagnosis. Management of PH in ILD comprises treatment of the underlying disease process and long-term oxygen therapy. Affected patients should be listed for lung transplantation without delay, when appropriate. However, due to age and comorbidities only a minority of ILD patients will be eligible for lung transplantation. In the absence of satisfactory therapies for many ILDs, and considering the clinical burden of PH in affected patients, specific vasomodulatory therapies presently approved for PAH may be promising options for ILD patients. Consequently, there is an urgent need for adequately designed clinical trials to assess the effectiveness of specific PH therapy in the context of ILDs.