Cardiac Effect of Interstitial Lung Disease Correlated with Spirometry and Six Minute Walk Test

Introduction The cardiac effect of different pulmonary functions, six minute walk distance, arterial blood gases and saturation in Interstitial Lung Disease (ILD) is not much known. So this study, a tertiary care hospital experience that entails to know the various factors in Pulmonary Hypertension (PH) mentioned above causing PH and their correlation with PH. Aim To study the correlation of PH in patients with ILD with spirometry and six minute walk test (6MWT). Materials and methods All consecutive patients with confirmed diagnosis of ILD taken over a period of 1½year in tertiary care hospital. 6MWT and spirometry were performed as per the American Thoracic Guidelines. Percent predicted 6 minute walk distance was calculated using Enright et al., and Indian reference equation. PH was diagnosed using 2-D echo. The spirometry variables and 6MWT were then correlated with the mean pulmonary artery pressure. Results There were 75 patients. About 66.66 % had PH on 2-D echo. The mean% predicted six minute walk distance as per the Indian reference equation, pre- and post- exercise PaO2 as well as desaturation had a significant correlation with PH. Spirometry variables Forced Expiratory Volume in First Second (FEV1) and Forced Vital Capacity (FVC) did not correlate with PH. Conclusion Thus, the 6MWT correlated significantly with PH while spirometry did not.