ROUTINE ILD TESTS

When your patient with ILD is getting worse, don't assume it's due to ILD—it may be PH⁴

Questions to consider asking your patients:

Why do they need supplemental oxygen now?²

Why is there a need to increase their supplemental oxygen?²

Do they have other signs of PH, like D_LCO >40%?^3-6

Can you confirm your ILD patient doesn’t have PH?

Was there evidence of PA enlargement during their last CT scan?²

Might poor results during exercise testing be due to PH?^2-4,11,12

Maintain a high degree of suspicion for PH.²

*Declining FVC and D_LCO are both measures of ILD disease progression and severity. In ILD, the decline in D_LCO is thought to be due to alveolar destruction and thickening/compression of pulmonary capillaries. PH can cause damage to the microvasculature, resulting in an additional decline in D_LCO that does not always correlate with FVC impairment.^{2-4,17-20
†}CPFE is commonly associated with the combination of preserved lung volumes and extremely low D_LCO and also carries a high risk for PH. WSPH recommends using an FVC/D_LCO ratio >1.6 as a threshold for suspecting PH in patients with ILD.^4,21
‡Based on studies using the 6MWT.^2-4

6MWT=6-minute walk test; BNP=B-type natriuretic peptide; CPFE=combined pulmonary fibrosis and emphysema; CT=computed tomography; D_LCO=diffusing capacity of the lung for carbon monoxide; FVC=forced vital capacity; ILD=interstitial lung disease; LV=left ventricle; NT-proBNP=N-terminal pro–B-type natriuretic peptide; PA=pulmonary artery; PFT=pulmonary function test; PH=pulmonary hypertension; RV=right ventricular/right ventricle; WSPH=World Symposium on Pulmonary Hypertension.