Echocardiographic Assessment of Biventricular Mechanics in Patients with Mild-to-Moderate Idiopathic Pulmonary Fibrosis: A Systematic Review and Meta-Analysis

Background: Over the last few years, a few imaging studies have performed con- ventional transthoracic echocardiography (TTE) implemented with speckle tracking echocar- diography (STE) for the assessment of biventricular mechanics in patients with non-advanced idiopathic pulmonary fibrosis (IPF). This systematic review and meta-analysis aimed at evalu- ating the overall effect of mild-to-moderate IPF on the main indices of biventricular systolic function assessed by TTE and STE. Methods: All imaging studies assessing right ventricu- lar (RV)-global longitudinal strain (GLS), left ventricular (LV)-GLS, tricuspid annular plane systolic excursion (TAPSE), and left ventricular ejection fraction (LVEF) in IPF patients vs. healthy controls, selected from PubMed, Scopus, and EMBASE databases, were included. Continuous data (RV-GLS, LV-GLS, TAPSE, and LVEF) were pooled as standardized mean differences (SMDs) comparing the IPF group with healthy controls. The SMD of RV-GLS was calculated using the random-effect model, whereas the SMDs of LV-GLS, TAPSE, and LVEF were calculated using the fixed-effect model. Results: The full texts of 6 studies with 255 IPF patients and 195 healthy controls were analyzed. Despite preserved TAPSE and LVEF, both RV-GLS and LV-GLS were significantly, although modestly, reduced in the IPF patients vs. the controls. The SMD was large (−1.01, 95% CI −1.47, −0.54, p < 0.001) for RV-GLS, medium (−0.62, 95% CI −0.82, −0.42, p < 0.001) for LV-GLS, small (−0.42, 95% CI −0.61, −0.23, p < 0.001) for TAPSE, and small and not statistically significant (−0.20, 95% CI −0.42, 0.03, p = 0.09) for LVEF assessment. Between-study heterogeneity was high for the studies assessing RV-GLS (I2 = 80.5%), low-to-moderate for those evaluating LV-GLS (I2 = 41.7%), and low for those measuring TAPSE (I2 = 16.4%) and LVEF (I2 = 7.63%). The Egger’s test yielded a p-value of 0.60, 0.11, 0.31, and 0.68 for the RV-GLS, LV-GLS, TAPSE, and LVEF assessment, respectively, indicating no publication bias. On meta-regression analysis, none of the mod- erators was significantly associated with effect modification for RV-GLS (all p > 0.05). The sensitivity analysis supported the robustness of the results. Conclusions: RV-GLS impairment is an early marker of subclinical myocardial dysfunction in mild-to-moderate IPF. STE should be considered for implementation in clinical practice for early detection of RV dysfunction in IPF patients without advanced lung disease.