Lung ultrasound plus transthoracic echocardiography for severity stratification in pulmonary fibrosis: a cross-sectional diagnostic study

BACKGROUND: Lung ultrasonography (LUS) is well-established for assessing pneumonia but underutilized in pulmonary fibrosis (PF). This study aimed to investigate the feasibility of LUS combined with transthoracic echocardiography (TTE) for assessment and stratification of PF. METHODS: In this cross-sectional study, consecutive patients with interstitial lung disease were enrolled and underwent LUS, TTE, chest high-resolution computed tomography (HRCT), and pulmonary function tests. The correlations between LUS, TTE findings, and disease severity were explored, and receiver operating characteristic (ROC) curve analysis was performed to evaluate the diagnostic accuracy for PF stratification. RESULTS: = 0.734 and 0.786, adjusted P < 0.001) and showed significant negative correlations with lung function. TTE assessment in severe PF revealed abnormalities including elevated echocardiographic probability of pulmonary hypertension, higher right ventricular diastolic dysfunction incidence, and lower tricuspid annular plane systolic excursion (TAPSE), among other parameters. For distinguishing severe from mild-moderate PF, the combination of LUS and TTE achieved an area under the ROC curve (AUC) of 0.962 (91.38% sensitivity, 87.76% specificity), which was significantly higher than that of either modality alone (P = 0.028). CONCLUSIONS: This study demonstrated that the findings of LUS were correlated with disease severity and pulmonary function of patients with PF. LUS score showed a good capacity for diagnosing severe PF, and this capacity was enhanced by combining with TTE.