Cardiovascular complications in patients with interstitial lung disease and their correlation with 6-minute walk test and spirometry: A single-center study

INTRODUCTION: Pulmonary hypertension and other cardiac complications occur frequently due to chronic hypoxia induced by interstitial lung diseases (ILD) or due to connective tissue disorder itself. Two-dimensional (2D) echocardiography is ideal for identifying abnormalities at a given time. In this study, we tried to detect cardiovascular complications in patients with ILD using 2D echocardiography and correlate them with a 6-minute walk test (6 MWT) and spirometry. MATERIALS AND METHODS: This study was carried out for 18 months including 100 consecutive cases of ILD. The diagnosis was made using the latest criteria as per the disease and high-resolution computed tomography (HRCT) thorax. All patients were evaluated with 2D echocardiography, 6 MWT, and spirometry along with routine investigations. Their results were analyzed using STATA 15.1 software. RESULT: Cardiovascular involvement was detected in 68% of cases. Pulmonary hypertension predominated with a prevalence of 50%. In spirometry, mean Forced expiratory volume in first second (FEV(1))and Forced vital capacity (FVC) were found to be 54.96 (L) and 53.49 (L), respectively, with a predominant restrictive pattern (89%). There was a significant correlation between baseline saturation of oxygen (SpO(2)) and pulmonary arterial systolic pressure (PASP) with a P value of <0.05. Baseline SpO(2) and distance covered in 6 MWT had a significant correlation (P = 0.014). CONCLUSION: A baseline or nighttime hypoxia is responsible for developing PAH. Pulmonary arterial hypertension should be suspected in patients unable to perform 6 MWT or having low baseline SpO(2). A routine follow-up with a 6 MWT and baseline SpO(2) should be performed in each visit to identify early deterioration of the disease.