Feasibility, reproducibility and diagnostic usefulness of right ventricular strain by 2-dimensional speckle-tracking echocardiography in ARDS patients: the ARD strain study.

Background: Right ventricular (RV) function evaluation by echocardiography is key in the management of ICU patients with acute respiratory distress syndrome (ARDS), however, it remains challenging. Quantification of RV deformation by speckle-tracking echocardiography (STE) is a recently available and reproducible technique that provides an integrated analysis of the RV. However, data are scarce regarding its use in critically ill patients. The aim of this study was to assess its feasibility and clinical usefulness in moderate-severe ARDS patients.

Results: Forty-eight ARDS patients under invasive mechanical ventilation (MV) were consecutively enrolled in a prospective observational study. A full transthoracic echocardiography was performed within 36 h of MV initiation. STE-derived and conventional parameters were recorded. Strain imaging of the RV lateral, inferior and septal walls was highly feasible (47/48 (98%) patients). Interobserver reproducibility of RV strain values displayed good reliability (intraclass correlation coefficients (ICC) > 0.75 for all STE-derived parameters) in ARDS patients. ROC curve analysis showed that lateral, inferior, global (average of the 3 RV walls) longitudinal systolic strain (LSS) and global strain rate demonstrated significant diagnostic values when compared to several conventional indices (TAPSE, S', RV FAC). A RV global LSS value > - 13.7% differentiated patients with a TAPSE < vs > 12 mm with a sensitivity of 88% and a specificity of 83%. Regarding clinical outcomes, mortality and cumulative incidence of weaning from MV at day 28 were not different in patients with normal versus abnormal STE-derived parameters.

Conclusions: Global STE assessment of the RV was highly achievable and reproducible in moderate-severe ARDS patients under MV and additionally correlated with several conventional parameters of RV function. In our cohort, STE-derived parameters did not provide any incremental value in terms of survival or weaning from MV prediction. Further investigations are needed to evaluate their theranostic usefulness. Trial registration NCT02638844: NCT.